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Low-temperature combustion (LTC) is a new combustion mode, and low cetane number fuels may be more appropriate for the LTC. Fuel properties play important roles both in the physical process...

The operation range of some new compression ignition (CI) combustion modes was extended compared to that of HCCI because of fuel stratification. Few researches tried to analyze the mechanism by comparison of flame development patterns and flame speed under different stratified conditions. In this work, high-speed imaging of natural flame luminosity was used to study the combustion process from homogeneous charge to stratified charge with a higher frame rate. Different stratification conditions were formed by adjusting the injection timings. Results show that the proportion of flame propagation increases and combustion reaction rate decreases as fuel distribution in cylinder changes from homogeneous charge to stratified charge. Flame propagation of auto-ignition kernel exists although the combustion is dominated by multipoint auto-ignition in HCCI combustion. The flame spreading speed is much higher than the flame speed because the fictitious reaction front is shorter than the actual reaction front for flame spreading speed calculation. Four principles are proposed for equivalent radius method to get more reasonable results of flame speed. For conditions that do not satisfy these principles, effective front method can be used. Flame speed in CI combustion modes is in the range of 10–50 m/s depending on different stratification conditions in current study. There is a good correlation between the flame speed and the peak heat release rate as SOI is retarded, i.e., high flame speed corresponds to high peak heat release rate. It can be concluded that controlling fuel stratification is an effective method to regulate the ratio between auto-ignition and flame propagation and achieve effective control on combustion reaction rate.

The effects of PODE and multiple fuel injection strategy on combustion and emission characteristics of a multiple-cylinder gasoline compression ignition (GCI) engine are investigated at high load (BMEP = 16 bar) operation condition with a fixed engine speed of 1660 r/min. Experimental results indicate that the sensitivity of soot emission to the variation of injection parameters is decreased by blending PODE with gasoline, mainly due to the enhanced soot oxidation through PODE’s high oxygen content. The main heat release of gasoline is more strongly affected by its pilot heat release compared to that of gasoline/PODE blends. Low PRRmax (maximum pressure rise rate) of about 4.5 bar/°CA can be obtained for gasoline with multiple-injection strategy, under which condition the advantage of gasoline/PODE blends only embodies in reducing soot emission, which is different from that with single injection strategy. The PHRRMI,max (maximum premixed heat release rate of main injection) and Kmain (heat release acceleration ratio of main injection) of gasoline show more sensitivity to the variation of EGR compared to that of PODE20 with pilot-main injection strategy, and the PHRRMI,max and PRRmax of gasoline increase more rapidly in contrast to that of gasoline/PODE blends as injection pressure increases. At higher injection pressure, the soot of all the fuels can be significantly decreased with penalty in PRRmax, especially for gasoline. It is seen that when PODE20 with triple-injection strategy, 1400 bar injection pressure and 30% EGR were employed under the operation condition with the engine speed of 1660 r/min and BMEP of 16 bar, the NOx of 1.3 g/kWh, soot of 0.007 g/kWh and BSFC of 199.67 g/kWh can be obtained while maintaining PRRmax of about 4.5 bar/°CA.

Both concentration stratification and reactivity stratification are beneficial for reducing the combustion rate and controlling the combustion phasing in HCCI (homogeneous charge compression ignition) operation. However, the different effects on combustion and emissions of concentration and reactivity stratification have not been fully explored and the interaction between the two stratification modes also needs to be clarified. Therefore, the effects of concentration stratification and reactivity stratification on combustion and emission characteristics were investigated in a single-cylinder diesel engine. The different concentration stratifications were designed by five port injection ratios to study the influence of concentration stratification. Cases with and without reactivity stratification were compared at the same overall reactivity and the same concentration stratification in the cylinder to roughly separate the impact of reactivity stratification. Results show that with the decrease of the premixed ratio, the peak heat release rate decreases, combustion phasing delays, and the thermal efficiency show the tendency of first decreasing and then increasing. For cases with same concentration stratification, the introduction of iso-octane/n-heptane reactivity stratification decreases combustion efficiency but increases indicated thermal efficiency, NOx (nitrogen oxides) emissions can be improved while CO (carbon monoxide) and HC (hydrocarbon) emissions are increased. The introduction of n-heptane/iso-octane reactivity stratification presents a positive effect on both thermal efficiency and combustion efficiency and contributes to the improvement in NOx, CO and HC emissions.

In recent years, thermal barrier coating (TBC) has been used as an effective way to reduce the heat transfer losses and to improve the thermal efficiency of internal combustion (IC) engine. In this study, a mathematic model has been proposed by taking the TBC material parameters into account, which is applied to explore the effects of TBC on engine combustion and emissions. Details of the combustion process is analyzed for the coated and uncoated engines under both low and high load conditions. The result shows that TBC has the ability of reducing wall heat transfer losses, thus improving the indicated thermal efficiency. A redistribution of different temperature regions is found with TBC and the coating shows better performance at rich mixture region due to higher temperature increase rate and at squish region due to higher surface/volume ratio. Both the soot oxidation process and NOx formation process are accelerated with TBC. However, TBC also enhances the overlap region between the high soot region and high temperature region, which accelerates the soot oxidation rate and greatly improves the soot emission.

Fuel properties play important roles both in the physical process of fuel air mixing and chemical process of combustion in the cylinder of diesel engines. There are many parameters to represent physical and chemical properties of a diesel fuel, which may affect combustion of diesel engine to different degrees. It is valuable to deeply understand the effects of fuel properties and the relations between some major properties as well. Therefore, the effects of diesel fuel properties on combustion and emissions have been experimentally investigated on a heavy-duty diesel engine in this study. In addition, the relationships among some major properties have been discussed. Twelve fuels with different fuel properties, which were produced by different refining processes from different refineries in China, were selected to ensure that the tested fuels have a wide representative. The results show that there is a strong correlation between fuel density and other fuel properties such as cetane number, aromatic hydrocarbon fraction, heat value, etc. Especially, the linear regression model between density and cetane number shows a certain reference significance. The cetane number of fuel with high density is low, which results in the delay of combustion and the rise of peak heat release rate at low load. There is no significant difference in brake thermal efficiency (BTE) for fuels with different fuel properties in the current study. However, the brake specific fuel consumption (BSFC) increases with the increase of fuel density because of the decrease in heat value. As the fuel density increases, the NOx emissions increase accordingly and the soot emissions roughly show an increasing trend as well. At low load, both CO and HC emissions obviously increase with the increase of fuel density. For example, at low load and low speed, CO and HC increase by 256%, 158% respectively as the fuel density increases from 800 kg/m3 to 920 kg/m3. Nonetheless, CO emissions remain a low level and show no obvious changes at medium and high loads, which is different from HC emissions that increase gradually especially for high speed conditions. The results of the European Steady-state Cycle (ESC) show that weighted BSFC and weighted emissions exhibit strong correlations with fuel density. When fuel density is bigger than a certain value (about 845 kg/m3), a rapid increasing trend is presented in the emissions of NOx, soot, CO and HC.

Oxygenated biofuels have become one of the research focuses of engines due to their renewability and improvement in combustion. There has been some studies concentrating on the dual fuel RCCI mode or blended combustion mode using biofuels in engines and valuable progress has been obtained. However, the comparison between biofuel RCCI and blended combustion modes has been rarely reported. Therefore, in current work, experimental study was conducted on a single-cylinder engine to investigate the differences between the two combustion modes fueled with biodiesel/n-butanol at different EGR rates (0%, 30%, 50%), n-butanol ratios (20%, 50%, 80%), injection timings and engine loads (low, medium, high). Results show that the ignition delay of blended mode is longer than that of RCCI mode, and more sensitive to n-butanol ratio and EGR rate. The optimum EGR rate is 30% considering efficiency and emissions for both combustion modes. Blended fuel mode can maintain high efficiency at all test loads and n-butanol ratios, the maximum indicated thermal efficiency (ITE) is up to 47.5%, while RCCI only shows comparable efficiency at high load. The problem of high maximum pressure rise rate (MPRR) that blended fuel mode faces can be addressed by retarded combustion phasing. Under current research conditions, blended fuel mode usually presents lower soot, HC, CO emissions and slight higher NOx compared with RCCI mode. Generally, blended mode has better performance when MPRR problem is addressed while RCCI mode shows the potential in load extension due to the low MPRR and flexible split ratio and injection timing.

The present study focuses on the experimental investigation on the optimal pilot injection strategy under GCI combustion mode in a multi-cylinder heavy-duty diesel engine. Three experiments were conducted at a high-speed high-load operating point with different operating parameters and emission targets, namely engine-out NOx target, fuel injection pressure, and main injection timing. The engine-out NOx targets were set to 5.0 g/kWh and 1.5 g/kWh, and the gasoline injection pressures were set to 100 MPa and 140 MPa. These high and low values represent different requirements of SCR efficiency and practical capability of fuel supply system when addressing the hypothetical future tailpipe NOx limit of 0.02 g/hp-hr (0.027 g/kWh). The results show that the use of optimized pilot injection always achieves lower pressure rise rate and soot emissions than the single injection baseline. The pilot gasoline fuel with low injection pressure is more ignitable than that with high injection pressures, hence a distinct heat release spike usually occurs for a pilot injection. The optimal pilot mass should be increased for a higher fuel injection pressure because the pilot fuel stratification level decreases. A relatively late pilot timing is preferable for the early main injection timing. For the late main injection timing, however, a relatively early pilot timing with large pilot mass is preferable and brings about a distinct two stage high temperature heat release, which can reduce the fuel consumption and soot emissions simultaneously. The two stage split combustion process obtained by double injection with retard combustion phasing can be considered to be an important way to alleviate the requirement of GCI fuel system.

To investigate the effect of biofuel properties on RCCI combustion and emissions, the experimental study was conducted on a single-cylinder diesel engine. Three low reactivity oxygenated biofuels, i.e. n-butanol, 2,5-dimethylfuran (DMF) and ethanol were injected in the intake port and biodiesel was directly injected into the cylinder to realize RCCI operation. Results show that the heat releases are changed from two-stage to single-peak with the increase of EGR rates. Biodiesel/ethanol presents 1 °CA longer ignition delay than the others, which indicates latent heat has significant effect on ignition delay. Under different injection timings, the trends of combustion and emissions are similar for three RCCI modes, meantime, biodiesel/ethanol shows greater potential on reducing NOx and soot emissions simultaneously (soot

Gasoline compression ignition (GCI) is a promising combustion concept with high thermal efficiency, low emissions, and minimal modification of standard engine hardware. With a relaxed constraint on the engine-out NOx emissions, different GCI operating parameters such as exhaust gas recirculation (EGR), injection timing, injection pressure, pilot-main injection interval, and pilot mass were swept to find their optimal calibrations. The entire operating map of a heavy duty diesel engine using GCI combustion with multi-injection strategies was also investigated. Results show that the use of pilot injection is effective in controlling the premixing heat release rate, reducing the combustion noise and emissions, and improving controllability, and allows for advancing combustion timing within the imposed mechanical constrains. With the engine-out NOx calibration of around 4.5 g/kW-h for typical Euro 6 compliant engines, the double injection strategy is applied over the entire operating map in GCI mode, and similar engine performance and emissions can be achieved by GCI combustion compared to conventional diesel combustion (CDC) mode, just using lower injection pressures. The peak brake thermal efficiency (BTE) of 44% over the entire operating map is demonstrated with minimal pumping and friction losses while keeping the peak cylinder pressure (PCP) within 16 MPa.

To determine the influence of physicochemical properties of fuels on emissions and operating range capacity in partially premixed combustion (PPC), n-heptane, gasoline, and n-butanol are blended into diesel by volume ratio of 80%, referred to as DH80, DG80, and DB80. Diesel is used as base fuel. Results show that the low viscosity of DH80 and DG80 has an adverse effect on their injection pressure capability and brake specific fuel consumption (BSFC). There is little difference in combustion characteristics between DH80 and diesel even with the great difference in volatility. DH80 achieves extremely high soot reductions compared to diesel at low load, while its reduction effect decreases gradually as load increases. Cetane number (CN) is the key factor influencing the mixing process for the part load, while the ignition delay of low CN fuels is sensitive to speed and load variations. As load increases, the effect of CN on the combustion process is greatly suppressed, and the molecular dilution effect on soot reduction outweighs the effect of CN. DB80 presents the best soot reduction performance due to its multi-dimensional fuel properties, but its full molecular structure potential on soot reduction at high load is limited due to its low energy density.

It is important to use hydrous ethanol in the engine due to the removal of water from fermented products of ethanol consumes lots of energy. In this study, the effect of hydrous ethanol on the combustion and emissions was investigated in dual-fuel reactivity controlled compression ignition (RCCI) mode with port-injected hydrous ethanol and direct-injected diesel. The purity of ethanol was changed from 60% to 100% in 10% increment by adding different volume water in pure ethanol. Meantime, the volume ratio of port-injected pure ethanol among the total fuel (abbreviated as RE) was set to 60% and 80%. Results show that the higher RE causes the decrease of the combustion efficiency and indicated thermal efficiency. With the decline of ethanol purity, the combustion efficiency decreases and the maximum pressure rise rate (MPRR) shows a tendency of firstly going down and then rising. The thermal efficiency has a small change in the ethanol purity range of 80%–100%, whereas the thermal efficiency is reduced remarkably at the ethanol purity of 60%. The reduction of ethanol purity can reduce NOx emissions but CO and THC emissions increase. Adjusting the intake temperature, EGR rate and injection pressure will improve the combustion and emissions.

The performances of three representative chamber geometries, i.e. the nebula, cross and reentrant geometries, in a stoichiometric operation natural gas engine with exhaust gas recirculation (EGR) were investigated through experiments and simulations. The results indicate that the cross and reentrant chambers show quite similar performances in improving the combustion and thermal efficiency, followed by the nebula chamber. The asymmetrical turbulence distribution and hence asymmetrical flame propagation, which reduce the flame development in a certain direction, should be one of the main reasons for increasing the combustion duration with nebula chamber. The cross chamber has similar issues; and its grooves could further reduce the flame surface. Its higher combustion rate than that of the nebula chamber can be mainly attributed to the stronger squish effect which results in a stronger turbulence during initial combustion stage. The reentrant chamber has the highest turbulence intensity before top dead center (TDC) and hence a higher flame surface density. Furthermore, it shows a more symmetrical flame propagation, and also a larger flame surface development during the late period of combustion. However, the effect of its turbulence on flame propagation reduces obviously after TDC since the high intensity region rapidly separates from the flame surface.

The paper presents a theoretical analysis and experimental study on the effects of parameters of two-stage turbocharging system on engine performance. A thermodynamic model was developed base on the first and second laws of thermodynamic to analyze the effects of different turbocharging parameters on engine boost pressure and pumping loss qualitatively. The numerical analysis results show that pressure ratio distribution (PRD) of compressors, inter-stage cooler, total turbine expansion ratio and turbine bypass or equivalent efficiency are the dominant factors affecting engine boost pressure, pumping loss and consequently the engine performance. Subsequently, those theoretical findings were applied in the matching and architecture optimization of a regulable two-stage turbocharging system, which comprises a high-pressure variable geometry turbocharger (VGT), a low-pressure fixed geometry turbocharger and an inter-stage cooler, for a heavy-duty diesel engine. The experiment was designed with a well matched two-stage turbocharging system to validate the theoretical findings and to optimize the engine fuel efficiency. The results indicate that inter-stage cooler does improve engine fuel efficiency by increasing intake manifold pressure and reducing pumping loss. Increasing the total turbine expansion ratio by reducing flow area of high-pressure stage VGT led to higher engine boost pressure, increased PRD and turbocharging efficiency variation, which results in increased pumping loss. The best fuel efficiency can be realized by compromising the engine boost pressure and pumping loss.

In this paper, the effects of pilot injection strategies, including various pilot injection timings and masses, on the combustion and emission characteristics of gasoline compression ignition are investigated in a multi-cylinder heavy duty diesel engine with the aim of reducing peak pressure rise rate while improving thermal efficiency and exhaust emissions. The results show that the HRR PI, max (peak heat release rate of pilot injection) becomes more sensitive to the change of pilot-main interval as the pilot injection mass increases, and the sensitivity of HRR PI, max to the change of pilot injection mass increases with the reduction of pilot-main interval. PHRR MI, max (peak premixed heat release rate of main injection) decreases with the decrease of pilot-main interval and the increase of pilot injection mass. The PRR max (peak pressure rise rate) and soot emission can be improved by 60.2% and 42.3% respectively, while still maintaining similar BSFC with optimized pilot injection strategy compared to single injection.

Natural gas (NG)-diesel dual-fuel combustion is an effective approach to reduce soot and greenhouse gas emissions and mitigate the liquid fossil fuel crisis. In this work, a comprehensive numerical study on the combustion and emission characteristics of a NG-diesel dual-fuel engine operating at the high load condition was performed. Six significant parameters such as the start of injection (SOI) timing, exhaust gas recirculation (EGR), injection and intake pressures, nozzle number, and NG substitution ratio were investigated. A pathway to achieve highly efficient and clean combustion was proposed. It was demonstrated that at least an EGR rate of 40% should be employed to meet the NOx Euro VI regulation limit. Although a higher injection pressure enhanced the diesel-air mixing process and promoted engine efficiency, the highest achievable engine efficiencies were similar using different injection pressures. An elevated intake pressure with an earlier SOI timing promoted the oxidation process. Therefore, it resulted in a lower combustion loss and thus higher engine efficiency. Furthermore, the increase of nozzle number effectively promoted the air utilization rate and expedited the combustion heat release, which resulted in a higher engine efficiency but lower soot emission. But the growing trend of engine efficiency was limited and a nozzle number of 11 was found to be the optimal option. Finally, a peak engine efficiency of about 47.6% was achieved with a NG substitution ratio of 95% and an optimized SOI timing, and meanwhile, both the NOx and soot emissions were below the Euro VI emission regulation limits.

Engine knock remains the key factor that ultimately restricts the peak thermal efficiency in modern downsized spark ignition (SI) engines. The flame propagation speed can affect knock tendency by the residence time and thermodynamic state of end-gas, which are competing with each other. The investigations in this study focus on flame propagation speed impacts on engine knock characteristics and thermal efficiency under a high load/low speed operating condition using three-dimensional numerical simulations. The results show that knock intensity (KI) increases first and thereafter decreases with the increase of SI flame speed under knocking condition. Behind the nonmonotonic relationship, the control mechanisms of end-gas auto-ignition are different. The low to moderate speed SI combustions are linked to local hot spots. Higher KI is caused by the interaction between the pressure waves induced by these hot spots. Then with the acceleration of SI flame, a homogeneous autoignition event occurs along the reaction front, leading to more intense pressure fluctuations. At the high-speed SI combustion, local hot spots disappear gradually, and the end-gas autoignition is dominated by flame-induced sequential auto-ignition. The corresponding KI decreases due to the reduction of available fresh gases. A posteriori analysis is also performed applying theories proposed by Zeldovich and Bradley. It’s shown that an increase in the SI flame speed results in lower first and thereafter higher temperature gradient in end-gas, leading to a drastic change in the auto-ignition behaviors. In addition, the relative effects of knock suppression and combustion duration reduction on thermal efficiency improvement are clarified.

In order to accelerate the flame propagation and hence to improve the thermal efficiency in the stoichiometric operation natural gas engine with exhaust gas recirculation, reentrant modification on the Cylindrical combustion chamber has been conducted in this study. The diameter ratio between chamber throat and cylinder bore (hereafter referred to as diameter ratio) has been gradually reduced from 0.64 to 0.46. The effects of the chamber reentrant level on the engine combustion and thermal efficiency were systematically investigated through experiments. Then the mechanisms of these effects were further clarified through both one-dimensional and three-dimensional simulations. The experimental results indicate that the combustion duration could be reduced continuously with higher chamber reentrant level, which is beneficial for the thermal efficiency improvement. However, this benefit will be gradually offset by the simultaneously increased knock tendency and heat transfer loss, which has been further validated through thermodynamic analysis on thermal efficiency with the help of one-dimensional simulation. As a consequence, the chamber with diameter ratio of 0.5, rather than 0.46, shows the best performance in this study, and the thermal efficiency can be improved by approximately 1.5% at full load condition and 3% at medium to high load conditions. In addition, through the experiments, it is also observed that the combustion duration with spark timing set at maximum brake torque point shows a good linear relationship with the diameter ratio. This function is greatly valuable to optimize the Reentrant combustion chamber since it could be obtained via few engine tests and then used for well predicting the effects of chamber reentrant level on thermal efficiency combined with only one-dimensional simulation. Through the three-dimensional simulation results, it is seen that the acceleration of the flame propagation with higher chamber reentrant level could be mainly attributed to the much increased flame surface wrinkle during the initial combustion period, which results from the increased turbulence level and its more obvious effect on the flame surface before top dead center during the combustion process.

In this study, experiments were conducted to improve the thermal efficiency by increasing the geometric compression ratio (GCR) to obtain higher expansion ratio, and using late intake valve closing (LIVC) Miller cycle to keep the effective compression ratio (ECR) within knock limit, in a stoichiometric operation natural gas engine with exhaust gas recirculation (EGR). The results indicate that, in a wide range of operating conditions, since the necessary exhaust gas recirculation dilution level leads to a large spark advance, the effective compression level around the spark timing has large difference and weak correlation with the effective compression ratio; in this case, the effect of the retarded intake valve closure (IVC) timing on lowering the compression temperature around the spark timing becomes much more significant; in addition, the increased geometric compression ratio could result in higher heat transfer loss around top dead center (TDC) due to the increased surface/volume (S/V) ratio. Consequently, even the effective compression ratio can be restored or further increased with higher geometric compression ratio compared to the baseline, the combustion rate is inevitably lowered or hardly increased. As engine speed and load increase, the adverse effect of the retarded intake valve closure timing on combustion rate could be further enhanced, mainly due to the increased cooling effect of the introduced and expelled charge on the cylinder wall. Through the thermodynamic analysis, it is observed that the adverse effect of the increased effective compression ratio on heat transfer loss is much more obvious compared to its positive effect on combustion rate, even within knock limit. All these factors restrict the thermal efficiency improvement potential obtained by the increased expansion ratio with higher geometric compression ratio. Finally, the net indicated thermal efficiency (ITEn) can be improved by nearly 2% at each tested operating condition with the optimization.

Gasoline partially premixed combustion (PPC) has been reported as an advancing concept for high efficient and clean combustion, while there still remains some obstacles. In this study, polyoxymethylene dimethyl ethers (PODE), which has superior properties of high oxygen content, high cetane number and no C C bond, is employed as an additive to optimize the properties of gasoline and solve the problems faced in gasoline PPC. The effects of gasoline/PODE blends with PODE volume blending ratio of 0, 10% and 20% on combustion and emission have been investigated from low to high loads in a multi-cylinder heavy-duty diesel engine. The experimental results show that the soot emission can be maximally reduced by 79% and 94% at high load when fueling PODE 10 and PODE20, respectively. The NOx-soot trade off relationship can be dramatically improved without penalty of fuel economy by fueling gasoline/PODE blends. The raw NOx and soot emissions can meet Euro V standards at high load and Euro VI standards at medium load by fueling both PODE10 and PODE20. Furthermore, the pressure rise rate can be maximally reduced by 24% and 47% when fueling PODE10 and PODE20. At medium load, the combustion controllability and sensitivity can be improved by gasoline/PODE blends. At low load, the COV IMEP can be reduced to 2.7% by fueling PODE20 which means a stable combustion can be obtained. Furthermore, the combustion efficiency can be dramatically improved from 85.1% to 99.6% by fueling PODE20, which leads to lower HC and CO emissions. Overall, PODE shows great advantage in solving the obstacles faced in gasoline PPC.

GCI (gasoline compression ignition), as one of the competitive low temperature combustion modes, has great potential to meet the increasingly stringent regulations. In order to understand the combustion mechanism of GCI through chemical kinetics, gasoline surrogates become the focus of research to reproduce the combustion and emission characteristics of real gasoline fuel. In this work, three gasoline surrogates have been compared with commercial RON92 gasoline on combustion and emission characteristics at different loads and EGR (exhaust gas recirculation) conditions. The results show that PRF (primary reference fuel) is not suitable to reproduce the combustion characteristics of RON92 gasoline. The soot emission of TRF (toluene reference fuel) is higher than that of gasoline at high load and high EGR (>20%) conditions. The THC (total hydrocarbons) of TRFDIB (toluene reference fuel with diisobutylene) is slightly higher than that of gasoline at medium and low loads. However, TRFDIB has the potential to better reproduce the NOx and soot emissions of RON92 gasoline under other conditions. The combustion characteristics can be well reproduced by TRFDIB within the whole range of test conditions. The chemical kinetics analysis results show that EGR (mainly CO2 and H2O) has inhibiting effect on the fuel with NTC (negative temperature coefficient) behavior and that the components with low NTC promote the ignition process with the increase of EGR comparatively. The addition of toluene slows down the conversion rate of iso-octane in TRF while the addition of DIB accelerates the surrogates’ oxidation rates, since DIB can produce more OH radical and CH2O to speed up the combustion process at low temperature.

The effects of low temperature reforming (LTR) of n-heptane/n-butanol blends on the flame development progress and combustion characteristic were investigated in an optical engine. The reforming temperatures were set as 423 K, 523 K and 623 K. Three n-heptane/n-butanol blending mixtures with volume fractions of n-butanol of 30% (B30), 50% (B50) and 70% (B70) were utilized. The detection, experiment and simulation methods included the gas chromatograph (GC) detection, high-speed imaging and chemical kinetics calculation. The main results are the following. Firstly, the LTR products were initially detected by the GC system. With the reforming temperature increasing, the mole fractions of aldehydes decrease. With the volume fraction of n-butanol increasing, the mole fractions of carbon monoxide, methanol and aldehydes increase while other species decrease. Secondly, the LTR products combined with the direct-injected fuel were introduced into the optical engine. For B30 and B50, the combustion phasing delays with the reforming temperature increasing. For B70, the combustion phasing initially advances and then delays with the reforming temperature increasing. Thirdly, the chemical kinetics simulation shows that most of the LTR products can decrease the mixture reactivity and delay the ignition timing, while small parts of the LTR products have the opposite effects.

In this work, a computational fluid dynamic model is established based on a natural gas engine and experimental results, and the combustion system of stoichiometric operation natural gas engine (intake manifolds and combustion chambers) is optimized based on knocking boundary extension under high load condition. In addition, the effects of Miller cycle and EGR on the combustion and knocking boundary extension are also explored. Results reveal that the intensity and distribution of in-cylinder turbulent kinetic energy will significantly affect the flame development and combustion characteristics. The combination of spiral intake manifold + K15 chamber shows better performance in antiknock because of the enhanced in-cylinder airflow motion and flame development. In addition, the Miller cycle with the late intake valve close timing of 20 °CA can effectively extend the antiknock performance of the engine under the current operating operation. EGR has limited effect on turbulent kinetic energy, and the primary affective mechanism of EGR on knocking is mainly achieved by changing the in-cylinder temperature during the combustion process. It is found that with tangential and spiral intake manifold + K15 chamber, combined with late intake valve closing (20 °CA) and EGR (30%), the indicated mean effective pressure (IMEP) can be increased by 5.21% within the knocking boundary compared to that of the original combustion system.

In this study, an experimental study has been conducted to explore the effects of soybean oil/PODE/ethanol blends on the combustion and emission characteristics in a diesel engine. Three tested fuels are 70% soybean oil/30% PODE by volume denoted as S70P30, 70% soybean oil/15% PODE/15% ethanol by volume denoted as S70P15E15 and baseline pure diesel denoted as D100. The impacts of CA50 and combustion duration at engine speed of 1415 rpm and 1.15 MPa BMEP are investigated. As the CA50 delays, BTE and NOx emissions decrease and soot emissions increase; as the combustion duration prolongs, BTE increases first and then decreases, NOx emissions decrease and soot emissions increase. CA50 has more significant effect on BTE, NOx and soot emissions than combustion duration. At the same CA50 and combustion duration, the trend in BTE and soot emissions is D100 > S70P15E15 > S70P30; for NOx emissions the trend is S70P30 > S70P15E15 > D100. For example, When CA50 is 17 °CA ATDC and the combustion duration is 25 °CA, the BTE of D100, S70P15E15 and S70P30 are 41.0%, 39.1% and 38.6%, respectively; the NOx emissions are approximately 6.4 g/kW·h, 7.0 g/kW·h and 7.8 g/kW·h, respectively; the soot emissions are 0.004 g/kW·h, 0.0011 g/kW·h and 0.0008 g/kW·h, respectively. Finally, the WHSC test cycle of Euro VI regulation is performed. Comparing two soybean oil blended fuels, S70P15E15 and S70P30 are similar in soot emissions, but S70P15E15 is lower in NOx emissions and weighted BSFC.

Partially premixed low-temperature combustion (PPC) has the potential to achieve efficient and clean combustion. Recent studies have shown that the octane number (ON) and sensitivity (S) are two of the crucial factors affecting combustion and emission in PPC. In order to improve the combustion and emission of PPC, this paper respectively used the toluene reference fuel (TRF) and ethanol reference fuel (ERF) to conduct experiments on a single-cylinder diesel engine to explore the effects of ON and S on combustion and emission of PPC. The experiments were carried out at high load with various exhaust gas recycle (EGR) rate and start of injection (SOI) timing. The results show that S shows stronger effects on combustion with RON90 fuels, and the indicated thermal efficiency (ITE) decreases when S is increased. The effect of S on the combustion and emissions of ERF70 and TRF70 is somewhat different. In terms of combustion phase control and highest ITE, the gap between ERF70 and TRF70 is close. But because the benzene ring in toluene promotes the formation of soot, while the ethanol has better volatility and the oxygen in fuels are favorable for soot oxidation, the soot emission of TRF70 is significantly higher than that of ERF70. It is found that TRF70 with low S (S

An experiment was conducted to investigate the combined impacts of biodiesel and n-pentanol properties on the performance and emissions of a common-rail diesel engine at different exhaust gas recirculation (EGR) rates. Tested fuels are noted as D100 (diesel fuel), B10P20 (10% biodiesel, 20% n-pentanol and 70% diesel, by vol.), B20P10 (20% biodiesel, 10% n-pentanol and 70% diesel, by vol.), P30 (30% n-pentanol and 70% diesel, by vol.) and B30 (30% biodiesel and 70% diesel, by vol.). The results indicate that compared to D100, the ignition delays of B20P10 and B30 show different results with increased EGR rates. That is, although the cetane number of B20P10 and B30 is lower, the ignition delays of B20P10 are shorter than that of D100 when the EGR rate is over 30%. The addition of n-pentanol to diesel will result in high maximum pressure rise rate, but ternary blends of biodiesel/n-pentanol /diesel can solve or alleviate the problem without obvious decrease of indicated thermal efficiency (ITE). At high EGR rates, ternary fuels shows the advantages in decreasing total hydrocarbons (THC). There is no significant difference in nitrogen oxides (NOx) emissions for all fuels at the same EGR rate. B10P20 and B20P10 can not only reduce soot emissions but also reduce carbon monoxide (CO) emissions under different EGR rates compared with diesel. To summarize, B20P10 fuel has a better potential for combustion and emission characteristics, especially at relatively high EGR rates.

Analysis of entropy generation and exergy loss is effective and essential in evaluating the fuel efficiency in next-generation internal combustion (IC) engines that are expected to operate at higher pressures. At such conditions, the hybrid deflagration/autoignition flame structures may exist during the combustion process. However, currently, most of the studies on entropy generation of laminar premixed flame are performed for mixtures at normal temperatures and pressures, under which the flame is stabilized by heat and mass transfer. This study compares the entropy generation and exergy loss characteristics when the transition of regime under engine-relevant conditions occurs, which is identified based on the ratio of the corresponding flame to homogeneous ignition time scales. The results indicate that when the transition from flame propagation to autoignition front occurs, the entropy generation and exergy destruction sources from heat and species mass transfer vanish and become dominated by chemical reactions. The total entropy generation from chemical reaction increases due to the larger flame thickness and variations in fuel consumption pathway. The reaction pathway analysis reveals that for the flame stabilized by autoignition with initial temperature located in the region of low-temperature and negative temperature coefficient chemistry, a great part of the entropy generation is produced by the low-temperature pathway, with the maximum flux ratio over 60%. Thus, more attention should be paid on the optimization of fuel consumption pathways to minimize the combustion irreversibility.

A combined reduced primary reference fuel (PRF)-alcohols (methanol/ethanol/propanols/butanols/n-pentanol) combustion kinetic mechanism composed of 161 species and 622 reactions was developed for engine combustion simulations. The obtained reduced PRF-alcohols mechanism was constructed with a hierarchical structure. Minor adjustments were performed to ensure the predictive performance against experimental results. The reduced PRF-alcohols mechanism adequately predicted experimental ignition delays, laminar flame speeds, and species mole fraction profiles. New homogeneous charge compression ignition experiments fueled with 75% (mol.) n-propanol/25% n-heptane, 75% i-propanol/25% n-heptane, and 75% n-pentanol/25% n-heptane blends were also collected and served as further mechanism validations. By coupled with the toluene-polycyclic aromatic hydrocarbons sub-mechanism, the reduced PRF-alcohols mechanism was used for the three dimensional modeling studies to investigate the direct injection compression ignition (DICI) combustion fueled with diesel/alcohol blends at the 5% fuel oxygen content. Zero-dimensional modeling studies were also conducted. The modeling results indicated that in DICI combustion, it was the different physical mixing qualities incurred by the different fuel reactivity dominated the soot formation but not the different carbon chain chemical structures. The O atom of the fuel molecule was more efficient than the O2 molecule for the soot oxidation.

The effects of biodiesel and its blends on the combustion and emissions were investigated on a single-cylinder diesel engine fueling three blends included biodiesel/n-butanol, biodiesel/ethanol and biodiesel/2,5-dimethylfuran. The results show that the indicated thermal efficiency (ITE) of pure biodiesel and three fuel blends are lower than that of diesel fuel at low load. With the increase of load, pure biodiesel and three fuel blends present higher ITE than that of diesel fuel, especially at high load and high EGR rates. The ability to reduce smoke can be sequenced as E20 > DMF20 > Bu20 > biodiesel. Pure biodiesel, B20 and DMF20 exhibit higher NOx emissions than that of diesel fuel, while E20 has lower NOx emissions than diesel. For three fuel blends, their HC and CO emissions are higher than those of diesel fuel at low load, but lower than diesel at higher loads. It is beneficial to further improve the thermal efficiency and reduce smoke at high load by increasing the blending ratio of high octane number oxygenated fuels. At 50% EGR rate, the soot reduction percentages are 79% and 99.4% for Bu50 and DMF50 respectively compared to diesel, and the thermal efficiency is further improved compared with 20% blending ratio.

An experimental investigation has been conducted to explore the effects of polyoxymethylene dimethyl ethers (PODE) as the direct-injection (DI) high reactivity fuel in dual-fuel reactivity controlled compression ignition (RCCI) operation on a single-cylinder, heavy-duty diesel engine. The combustion and emission characteristics, together with the combustion phasing controllability of gasoline/diesel and gasoline/PODE RCCI operation are compared and discussed. The results show that stable and controllable RCCI operation is obtainable using PODE as the DI high reactivity fuel. Improved indicated thermal efficiency (ITE) and ultra-low smoke can be achieved with PODE, with a slight penalty, but still comparable NOx emissions. The maximum load of gasoline/PODE operation could be extended to 1.76 MPa indicated mean effective pressure (IMEP) with a single injection strategy, which is significantly higher than that of gasoline/diesel operation with an optimized double-injection strategy (1.39 MPa IMEP), while still maintaining ultra-low smoke and comparable ITE and PPRR. Stoichiometric and clean gasoline/PODE dual-fuel RCCI operation was also achievable at high load. This enables the possibility to apply a low-cost three-way catalyst to further reduce the NOx, HC and CO emissions, which offers a very competitive pathway to achieve clean and highly efficient diesel combustion.

Reactivity controlled compression ignition (RCCI) is demonstrated as a promising combustion strategy to achieve high efficiency and clean combustion. However, less effort has been devoted to examine the achievable RCCI operational range over a wide range of engine speed. In addition, previous studies have found that superior EGR rate and high diesel/gasoline fuel ratio are required to ease the extension of the low-load operating range of RCCI regime. Even then, relatively high CO and HC (unburned hydrocarbon) emissions and the accompanying fuel con-sum ption penalty still remain a problem to be resolved. Therefore, in this work the potential of diesel-fueled LTC to achieve simultaneously low NOx and soot emissions while maintaining high thermal efficiency at low load (IMEP ≈0.23–0.26 MPa) is investigated and compared with the gasoline/diesel RCCI strategy. The results show that the diesel LTC operation can yield slightly higher soot and NOx emissions (soot: 0.002 g/kW h, NOx: 0.446 g/kW h), but CO and HC emissions as well as the fuel consumption are much lower than the RCCI strategy, implying the diesel LTC regime may be more suitable for low-load operations. In addition, the RCCI operational range at speeds ranging from 900 to 2500 r/min is determined, the results show that the maximum achievable load (IMEP) increases with an increase in speed, and a maximum IMEP of 1.2 MPa can be achieved at an engine speed of 2300 r/min. Ultra-low NOx and soot emissions (soot

Reactivity controlled compression ignition (RCCI) is demonstrated as a promising combustion strategy to achieve high efficiency and clean combustion. In this work, an extensive experimental investigations are performed focusing on investigating the effect of operational parameters (intake pressure, exhaust gas recirculation rate, gasoline proportion, diesel injection timing, etc.) on the combustion performance and emission characteristics at various engine loads. Then, the key limiting factors for extension of the upper and lower limits of RCCI operations are analyzed. Results suggest that ultra-low NOx and soot emissions as well as high thermal efficiency can be achieved simultaneously with gasoline/diesel dual-fuel RCCI regime at moderate-to-high loads, while diesel low temperature combustion (LTC) with single-shot fuel injection can be more suitable for low-load operations. Moreover, to extend the RCCI operating range to lower loads, the proportion of diesel injection should be raised to increase the global reactivity of the in-cylinder charge. While increasing EGR rate and gasoline proportion as well as advancing diesel injection timing can lower the global reactivity of the cylinder charge and avoid premature combustion, excessive pressure rise rate and high peak in-cylinder pressure, thereby in favor of extending RCCI operation to higher loads. However, ultra-high EGR rate or too early fuel injection can lead to unstable combustion, making combustion phasing control extremely difficult.

Polyoxymethylene dimethyl ethers (PODE) is an emerging biofuel with properties of high cetane number (CN), high oxygen content and no C–C bond, which shows a significant potential to achieve high efficient and clean combustion and to be one of the competitive alternative fuels for diesel engine. In the current study, the effects of diesel/PODE blends on the combustion and emission characteristics with the PODE volume blending ratio of 15% and 25% have been experimentally investigated in a heavy duty diesel engine. Fuel properties optimization coupled with exhaust gas recirculation (EGR) is utilized to achieve high efficient and clean combustion. The combustion and emission characteristics of diesel, PODE15 and PODE25 are compared at low, medium and high loads. The experimental results show that blending PODE can accelerate the combustion rate in the late combustion phase and it is also beneficial for soot emission reduction, especially at low excess air ratio conditions. The HC and CO emissions can be improved by fueling diesel/PODE blends. The NOx emission of diesel/PODE blends can be slightly improved, while the brake thermal efficiency (BTE) is penalized at low and medium loads. As the NOx is further decreased to relatively low values by increasing EGR at high load, the BTE of diesel/PODE blends gradually gets close to that of diesel and shows the capability to improve BTE. The NOx–soot trade off relationship can be dramatically improved by fueling diesel/PODE blends. The weighted results over the World Harmonized Stationary Cycle (WHSC) indicate that the raw soot emission of PODE25 can meet the Euro VI soot emission standard when the weighted NOx is controlled at 2.7 g/kW h, In this case, a selective catalytic reduction (SCR) device with an average conversion efficiency of 85% is adequate to meet the Euro VI NOx emission standards for PODE25, which means that the requirement on aftertreatment device for achieving low emissions can be reduced by fueling diesel/PODE blends.

An experimental study has been conducted to explore the effects of five different valve strategies, including three intake valve closure (IVC) timing strategies and two rebreathing strategies (i.e., second opening of the intake/exhaust valves during the exhaust/intake processes, called 2IVO and 2EVO) on the combustion and emission characteristics at various low loads (1–5 bar gross indicated mean effective pressure, IMEP g ) on a heavy-duty diesel engine. Then proper valve strategies to achieve clean combustion (Engine-out emission: NO x ~0.4 g/kW-hr, Smoke x emissions within low levels, the externally cooled exhaust gas recirculation (Ex-EGR) was used and combined with three IVC strategies in this study, while internal EGR (In-EGR) was used with 2IVO and 2EVO strategies. The results show that low NO x emissions can be achieved for these valve strategies with high In-EGR or Ex-EGR. However, the differences among various valve strategies on other emissions (CO, HC and Smoke) and combustion characteristics are sensitive to engine loads. Improved combustion and emissions can be achieved with rebreathing strategies at low loads (1–2 bar IMEP g ), however, higher Smoke emissions and lower thermal efficiency are observed at higher loads. The lowest Smoke emissions can be obtained with the late IVC strategy, but at the same time with high CO and HC emissions, especially at lower loads. The suggestion is to use the rebreathing valve strategies at lower engine load from 1 to 2 bar IMEP g and then change to the standard and late IVC strategies at higher loads.

With the increase of information processing speed, more and more engine optimization work can be processed automatically. The quick-response closed-loop control method is becoming an urgent demand for the combustion control of modern internal combustion engines. In this paper, artificial neural network (ANN) and polynomial functions are used to predict the emission and engine performance based on seven parameters extracted from the in-cylinder pressure trace information of over 3000 cases. Based on the prediction model, the optimal combustion parameters are found with two different intelligent algorithms, including genetical algorithm and fish swarm algorithm. The results show that combination of quadratic function with genetical algorithm is able to obtain the appropriate combustion control parameters. Both engine emissions and thermal efficiency can be virtually predicted in a much faster way, such that enables a promising way to achieve fast and reliable closed-loop combustion control.

The fuels of internal combustion (IC) engines are gradually becoming diverse. However, differences in physicochemical properties among fuels result in different efficiency potentials. In this work, the factors affecting exergy destruction and engine efficiency of various classes of fuel were identified based on the first- and second-law of thermodynamics. The results demonstrate that exergy destruction fraction (fEx_D) shows strongly positive correlation to the ratio of fuel chemical exergy (LExV) to lower heating value (LHV) (e) and dimensionless entropy change (αS), and the first-law efficiency has strongly positive correlation to the product ratio of specific-heat during combustion (γc). Specifically, small molecule fuels have lower first-law efficiency than large ones, while the second-law efficiency of hydrocarbons are higher than that of oxygenates due to their lower exergy destruction losses. However, the lower exergy destruction does not always lead to improved second-law efficiency, but increased exhaust exergy. With increasing air or EGR dilution, both the first- and second-law efficiency increase, but the increased exergy destruction results in the reduced exhaust exergy. As a result, it is more important and reasonable to design or reform fuel for increasing the thermal efficiency, rather than reducing the exergy destruction of IC engines.

The effects of fuel properties and coolant temperatures on combustion characteristic and flame development progress were investigated in an optical engine. The combustion mode was transited from homogeneous charge compression ignition (HCCI) to conventional diesel combustion (CDC) via partially premixed combustion (PPC) by changing the start of injection (SOI) timings from early to late injections. The main fuel properties were separated by using diesel, n-heptane, iso-octane, n-butanol and their mixtures. Diagnostics included conventional in-cylinder pressure and heat-release analysis, high-speed imaging and the spatially integrated flame luminosity intensity. The results show that the variation of combustion phasing (CA50) is more sensitive to the variation of fuel properties of cetane number, latent heat and atomic oxygen at all tested combustion modes. However, fuel physical properties such as dilution, viscosity and volatility only have significant effects at HCCI, while minor effects at PPC and CDC. Fuel properties have minor effects on flame development progress, but significant effects on maximum value of natural flame luminosity intensity. At SOI-15, the main factor to reduce the maximum value of natural flame luminosity intensity is the dilution, viscosity and volatility (40%) followed by the latent heat and the atomic oxygen (18.5%) and cetane number (1.6%). At SOI-5, the main factor is the cetane number (44.1%) followed by the latent heat and the atomic oxygen (36.2%) and dilution, viscosity and volatility (2.4%). Coolant temperature significantly influences combustion phasing and peak in-cylinder pressure and heat release rate at early injection timings, but these effects weaken at late injection timings.

Polyoxymethylene dimethyl ethers (PODE) is a promising alternative fuel for diesel engine with high cetane number, high oxygen content and no C C bond, which is beneficial for achieving clean combustion. Furthermore, PODE can be employed as a co-solvent for alcohol/diesel blends, and stabilizes the miscibility of ethanol/diesel blends. In this study, the effects of ethanol/diesel/PODE blends on the combustion and emissions characteristics were studied in a six-cylinder heavy duty diesel engine. The experimental results show that blending ethanol and PODE into diesel can accelerate the combustion rate in late combustion stage at all loads. Blending PODE and ethanol to diesel, the BSFC of blends increase and the BTE of blends are basically same as that of D100 at low and medium loads. As the load increases, the reduction of HC and soot emissions of blends compared with D100 weaken, and the growth of NOX emissions of blends compared with D100 increase. The performance and emissions of different fuels were also evaluated based on the World Harmonized Stationary Cycle (WHSC) test cycle. As the blending ratio of PODE and ethanol increase, the weighted BSFC increases significantly, but the weighted equivalent BSFC increase slightly. The weighted HC emissions decrease and the weighted NOX emissions increase with ethanol/diesel/PODE blends. Blending PODE and ethanol can reduce the weighted CO emissions; however, as the blending ratio of ethanol increases, the decrease trend of weighted CO emissions get weakened, and DPE15 even exhibits increasing trend compared to D100, which is attributed to the increasing CO emissions at cold idle condition. With the blending ratio of PODE and ethanol increasing, the weighted soot emissions are reduce apparently, and the highest reduction ratio is 86.9% for DPE15 fuel.

An experimental investigation on the combustion and controllability of the partially premixed combustion (PPC) fueled with n-butanol was conducted on a modified single-cylinder compression ignition engine. The effects of engine loads, intake pressure, exhaust gas recirculation (EGR), and two-stage injection strategy were studied. The results show that the controllability of the n-butanol PPC combustion is poor, which is even worse under low load. In addition, the controllability of the n-butanol PPC combustion is significantly sensitive to the EGR rate and a high EGR rate will result in the poor controllability, and it can be improved when appropriate small proportion of EGR is adopted. However, the controllability can be improved and high peak pressure rise rate (PPRR) can be reduced through adopting a high intake pressure, which is quite effective under the low-load condition. Furthermore, the deterioration of the controllability at a high EGR rate can also be improved by increasing the intake pressure. Meanwhile, compared with a single injection strategy, the adoption of the two-stage injection strategy has a remarkable effect on improving the controllability of the n-butanol PPC combustion, which however, leads to a slightly lower indicated thermal efficiency due to the longer combustion duration.

Coal to liquid (CTL) is one of the potential methods to obtain the alternative fuel used in diesel engines. There are two methods to obtain alternative fuel from coal, namely, indirect and ...

In the current study, a commercial diesel fuel was redistilled and four fuels with different distillation temperatures were obtained. The effects of fuels with different distillation temper...

In recent years, polyoxymethylene dimethyl ethers (PODE) is used for reactivity gradient enlargement in direct injection engines due to its high Cetane Number (CN). In the current study, thermal efficiency improvement of PODE/Gasoline dual-fuel reactivity controlled compression ignition (RCCI) high load operation with exhausted gas recirculation (EGR) and air dilution is experimentally investigated, together with a zero-dimension (0-D) thermodynamic analysis. The experimental result shows that 15% gross indicated thermal efficiency (ITEg) improvement can be achieved through both air dilution and EGR dilution. Air dilution under fixed intake pressure shows significant effects on ITEg improvements. EGR dilution under fixed equivalence ratio (Φ) slightly reduces the ITEg. Further study with fixed the total charge heat capacity reveals that at lean conditions, the total charge heat capacity has greater influence on the combustion processes and ITEg than equivalence ratio. Comparing the experimental results with the thermodynamic modelling results, it indicates that combustion efficiency is an important factor that determines the ITEg with air/EGR dilution. Further analysis reveals that air dilution greatly improves the CO oxidation owing to the increased oxygen concentration, which obviously improves the combustion efficiency and ITEg.

Polyoxymethylene dimethyl ethers (PODE) is an emerging alternative fuel, which has been extensively investigated and shows great potential to improve the combustion performance in both conventional diesel engine and novel combustion modes. In this paper, the spray characteristics of gasoline/PODE and diesel/PODE blends under different injection pressures and ambient pressures were investigated in a constant volume chamber under both non-evaporating and evaporating conditions. Experimental results show that under evaporating condition, the spray tip penetration of PODE is higher than gasoline, but shorter than diesel due to different volatility, along with smaller spray cone angle compared to diesel, and reduced spray cone angle can be obtained with higher injection pressure. Under non-evaporating condition, longer spray tip penetration and larger spray cone angle are observed with PODE. PODE is beneficial to reduce the equivalence ratio along the axial and radical directions for both gasoline and diesel due to its high oxygen content. In the meanwhile, PODE has larger SMD compared to gasoline, and smaller SMD for gasoline, diesel and PODE can be obtained by increasing injection pressure and lowering the ambient pressure. At last, the experiment data provided in this paper will also contribute to the spray model calibration.

The effects of three kinds of oxygenated fuel blends—i.e., ethanol-gasoline, n-butanol-gasoline, and 2,5-dimethylfuran (DMF)-gasoline-on fuel consumption, emissions, and acceleration performance were investigated in a passenger car with a chassis dynamometer. The engine mounted in the vehicle was a four-cylinder, four-stroke, turbocharging gasoline direct injection (GDI) engine with a displacement of 1.395 L. The test fuels include ethanol-gasoline, n-butanol-gasoline, and DMF-gasoline with four blending ratios of 20%, 50%, 75%, and 100%, and pure gasoline was also tested for comparison. The original contribution of this article is to systemically study the steady-state, transient-state, cold-start, and acceleration performance of the tested fuels under a wide range of blending ratios, especially at high blending ratios. It provides new insight and knowledge of the emission alleviation technique in terms of tailoring the biofuels in GDI turbocharged engines. The results of our works showed that operation with ethanol–gasoline, n-butanol–gasoline, and DMF–gasoline at high blending ratios could be realized in the GDI vehicle without any modification to its engine and the control system at the steady state. At steady-state operation, as compared with pure gasoline, the results indicated that blending n-butanol could reduce CO2, CO, total hydrocarbon (THC), and NOX emissions, which were also decreased by employing a higher blending ratio of n-butanol. However, a high fraction of n-butanol increased the volumetric fuel consumption, and so did the DMF–gasoline and ethanol–gasoline blends. A large fraction of DMF reduced THC emissions, but increased CO2 and NOX emissions. Blending n-butanol can improve the equivalent fuel consumption. Moreover, the particle number (PN) emissions were significantly decreased when using the high blending ratios of the three kinds of oxygenated fuels. According to the results of the New European Drive Cycle (NEDC) cycle, blending 20% of n-butanol with gasoline decreased CO2 emissions by 5.7% compared with pure gasoline and simultaneously reduced CO, THC, NOX emissions, while blending ethanol only reduced NOX emissions. PN and particulate matter (PM) emissions decreased significantly in all stages of the NEDC cycle with the oxygenated fuel blends; the highest reduction ratio in PN was 72.87% upon blending 20% ethanol at the NEDC cycle. The high proportion of n-butanol and DMF improved the acceleration performance of the vehicle.