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The focus of this paper is on the verification and validation of computational approaches commonly used for the simulation of in-cylinder processes involving intense turbulent flow and combustion. Furthermore, the tumble behavior during the intake stroke at different engine operating points is investigated since the cycle-to-cycle variability of the subsequent tumble breakdown at the end of compression stroke is reported to negatively affect the engine efficiency. In this respect, measurements with advanced laser diagnostics-based experimental techniques (TR-PIV) in an optically accessible engine have been performed and compared with LES for flow in the same engine, under identical operating conditions. The study focused on the intake stroke under wide open throttle conditions and engine speed of 1000 RPM and 1500 RPM. The ensemble averaged velocity fields of the two methods were analyzed and compared. A counter-clockwise motion and some secondary recirculation zones were identified and quantified in both methods. The same trend for tumble ratio was observed between experiments and simulations and a good agreement was found for most CAD especially at 1500 RPM. At 1000 RPM comparison showed significant variations, which after a detailed analysis of the instantaneous fields, are attributed to the strong cycle-to-cycle variability of the instantaneous tumble center. It is observed, that for relevance index values below 0.75 the ensemble averaged flow fields that the two methods predict significantly differ.

A port injection engine that supplies hydrogen to the intake manifold or port exhibits a low intake air amount and torque output. The torque output is limited by backfire. In the present study, the performance and efficiency of a port injection-type hydrogen engine using the fuel injector of a natural gas engine is investigated at various engines speeds under wide open throttle conditions and two operation strategies, i.e., limiting nitrogen oxide emission and maximizing the torque. The increase in electrode temperature is reduced by increasing the heat rating number of the spark plug or reducing the ignition energy applied to the spark plug. Even when the ignition energy is reduced, as the minimum ignition energy of hydrogen is very low, it does not eliminate backfire. However, when a cold-type spark plug is used, backfire is effectively suppressed, resulting in an increase in the maximum torque and a decrease in efficiency.

This work focuses on exctracting ethanol from waste pomegranate (Punica granatum) and the experimental investigation of impact of various mixtures on emissions and engine performance. Ethanol is produced through the fermentation process of waste pomegranate fruits. Four combinations, namely E10, E15, E20, and E25, were prepared and tested for various speeds with a wide open throttle at 10:1 compression ratio. As a result, it was found that the ethanol enrichment increased the fuel consumption and power for braking while the thermal efficiency decreased. CO-produced HC has decreased, but ethanol concentrations have increased the NOx and CO2 content emitted from the exhaust gas. The 1500RPM engine speed and the E15 combination revealed the optimal values of performance parameters among all the fuel combinations studied.

In the current investigation, a four stroke, variable speed, single cylinder, variable compression ratio (VCR) SI engine is operated with raw biogas at wide open throttle (WOT) condition and at five different CRs ranging from CR 10 to CR 14 over the operating speed range of the engine. The ignition timing (IT) of the engine is also varied from 23○CA to 47○CA before top dead centre (bTDC) at each operating CR. The optimized operating CR and IT of the engine are obtained through series of experiments and its effects on the performance, combustion and emission characteristic are analysed herein. The rise in operating CR from CR 10 to CR 12 enhanced the power output and efficiency of the biogas fueled SI engine by 12.72% and 5.68%, respectively and reduced fuel consumption by 5.42% at 1400 rpm. Enhancing the CR from CR 10 to CR 12, limited the intensification of NOx and unburnt hydrocarbon emission by 10.17% and 15.6%, respectively at 1400 rpm. Hence, CR 12 is recommended as the optimum CR and its combination with 1400 rpm and WOT setting is recommended as the best operating condition of the engine.

The main purpose of this study is to optimize engine performance and emission characteristics of off-road engines with retarded spark timing compared to MBT by repurposing the existing passenger engine. This study uses a one-dimensional (1D)-simulation to develop a non-road gasoline MPI turbo engine. The SI turbulent flame model of the GT-suite, an operational performance predictable program, presents turbocharger matching and optimal operation design points. To optimize the engine performance, the SI turbulent model uses three operation parameters: spark timing, intake valve overlap, and boost pressure. Spark timing determines the initial state of combustion and thermal efficiency, and is the main variable of the engine. The maximum brake torque (MBT) point can be identified for spark timing, and abnormal combustion phenomena, such as knocking, can be identified. Spark timing is related to engine performance, and emissions of exhaust pollutants are predictable. If the spark timing is set to variables, the engine performance and emissions can be confirmed and predicted. The intake valve overlap can predict the performance and exhaust gas by controlling the airflow and combustion chamber flow, and can control the performance of the engine by controlling the flow in the cylinder. In addition, a criterion can be set to consider the optimum operating point of the non-road vehicle while investigating the performance and exhaust gas emissions accompanying changes in boost pressure With these parameters, the design of experiment (DoE) of the 1D-simulation is performed, and the driving performance and knocking phenomenon for each RPM are predicted during the wide open throttle (WOT) of the gasoline MPI Turbo SI engine. The multi-objective Pareto technique is also used to optimize engine performance and exhaust gas emissions, and to present optimized design points for the target engine, the downsized gasoline MPI Turbo SI engine. The results of the Pareto optimal solution showed a maximum torque increase of 12.78% and a NOx decrease of 54.31%.

In this study, the engine performance and emissions of gasoline were examined by applying a response surface methodology (RSM) optimisation approach. Fusel oil–gasoline blends were used to operate an engine at various speeds and loads. The optimal fusel oil–gasoline blend mix ratio was determined to minimise fuel consumption and nitrogen oxide and hydrocarbon emissions and to maximise the brake power (BP). The results demonstrate that the engine load and speed have a significant effect on performance and emissions. In addition, the blended fuels (F10 and F20) were shown to reduce NOx emissions. Furthermore, insignificant effects on engine performance were observed for fusel oil compared with pure gasoline. The design of experiments (DoE) method, which is a statistical technique, indicated that F20 was the optimum blend ratio among the three studied fuels, based on the RSM. The optimal parameters were a load corresponding to 60% of the wide open throttle engine load and an engine speed of 4500 rpm for the F20 blend, resulting in a high desirability value of 0.852 for the test engine, with values of 67.6 kW, 235.17 g/kW.h, 0.118%vol, and 1931.4 ppm for the BP, brake-specific fuel consumption, CO emission, and NOx emission, respectively.

In the present investigation, experiments were conducted in wide open throttle condition (WOT) for different speed ranging from 1400 rpm to 1800 rpm at an interval of 200 on a single-cylinder four-...

The direct-injection concept in gasoline engines induces emission problems due to wall impingement of fuel and lack of mixing time, compared to port-fuel-injection engines. One of the solutions for these problems is optimization of the spray pattern. In this study, injector nozzle arrangement and injection timing were optimized under the wide-open-throttle condition using computational fluid dynamics. An injection pressure of 33 MPa was utilized. Mixture homogeneity, turbulent kinetic energy, and fuel film mass were monitored to evaluate the intermediate optimal design. These variables comprise the objective function. The nozzle arrangement was restricted to consider the processability and reduce computational costs. The KIVA-3V release 2 code was combined with the optimization tool. Depending on the design, the amount of leaking along the outflow to the intake port at the end of the intake process varies, however the injection quantity was maintained for simplification of optimization process. After optimization, the vapor fuel mass fraction in the intake port was considered to form a stoichiometric mixture, and mixture formation and combustion processes were analyzed. The optimal design had a narrower pattern than the reference design and targeted the downward direction when mounted on the engine because it is easy to increase in-cylinder turbulence intensity. The optimal design showed that the mixture homogeneity increased by 0.86% based on homogeneity index and the fuel film mass decreased by 51%, while the turbulent kinetic energy showed no significant change. The exhaust emissions (carbon monoxide, hydrocarbon, soot, nitrogen oxide) were reduced, while the indicated mean effective pressure remained constant.

A novel electric powertrain system with integrated motor and two-speed gearbox is developed for a pure electric and all-wheel-drive SUV (Sport Utility Vehicle) to balance the energy consumption and drive quality. The e-powertrain layout of this all-wheel-drive SUV is investigated, a traditional single-speed gearbox is selected for FDM (Front Drive Module) and a novel two-speed gearbox is adopted for RDM (Rear Drive Module). A series of verification tests are performed and the efficiency data and drag loss under different working conditions are generated through the efficiency bench test follow China GB standards. The all-wheel-drive vehicle and e-powertrain models are created based on calculation software, then the energy consumption in WLTP cycle, WOT (Wide Open Throttle) performance of the two-speed gearbox are analyzed. It finds that the RDM with two-speed e-powertrain system will bring 3.64% energy reduction thanks to extending the motor working opportunity in higher efficiency area, 3.99% energy reduction thanks to the neutral gear function to reduce the energy loss during the cruise and coast-down running conditions, totally 7.63% energy saving in WLTP cycle is achieved. Meanwhile, the dynamic performances maintain in a competitive level.

Geometrical features of combustion chamber are important factors in subsequent engine’s combustion and emissions. Control over combustion that is difficult to attain due to the complexity of the processes involved is the key objective in designing the combustion chamber. Reduction of engine emissions and fuel consumption can be reached by an improved control over the degree of homogeneity of the air–fuel mixture, cycle-to-cycle variation, and turbulence intensity. The CFD simulation to investigate the effect of piston bowl of a four-stroke direct injection compression ignition engine under the operating condition is presented. The analyses are dedicated to investigate the outcome of the piston shape differences to the fluid flow and turbulence characteristics for air–fuel mixture preparation in terms of turbulence kinetic energy. The numerical calculations were performed in a single cylinder direct injection compression ignition engine running at wide open throttle condition by using the CFD code. Two different piston bowls for certain engine speeds were considered to compare and evaluate the mentioned parameters produced during intake and compression stroke. The results obtained from the numerical analysis can be employed to examine the homogeneity of air–fuel mixture configuration for better combustion process and engine performance.

The objective of the paper is to study the environmental performance of a gasoline engine operating on methane. The study involves experiments and comparing the results obtained with the parameters of the test running of the same engine on gasoline. Multiple tests have been conducted, thus providing for collecting information about various environmental parameters of the engine operating on methane fuel and gasoline. The results presented were obtained with wide open throttle engine operation, optimal air-fuel ratios and ignition timing.

A range extender (RE) is a device used in electric vehicles (EVs) to generate electricity on-board, enabling them to significantly reduce the number of required batteries and/or extend the vehicle driving range to allow occasional long trips. In the present work, an efficiency-oriented RE based on a small motorcycle engine modified to the efficient over-expanded cycle, was analyzed, tested and simulated in a driving cycle. The RE was developed to have two points of operation, ECO: 3000 rpm, very high efficiency with only 15 kW, and BOOST: 7000 rpm with 35 kW. While the ECO strategy was a straightforward development for the over-expansion concept (less trapped air and a much higher compression ratio) the BOOST strategy was more complicated to implement and involved the need for throttle operation. Initially the concepts were evaluated in an in-house model and AVL Boost&reg, (AVL List Gmbh, Graz, Austria), and proved feasible. Then, a BMW K75 engine was altered and tested on a brake dynamometer. The running engine proved the initial concept, by improving the efficiency for the ECO condition in almost 40% in relation to the stock engine and getting well over the required BOOST power, getting to 35 kW, while keeping an efficiency similar to the stock engine at the wide open throttle (WOT). In order to protect the engine during BOOST, the mixture was enriched, while at ECO the mixture was leaned to further improve efficiency. The fixed operation configuration allows the reduction, not only of complexity and cost of the RE, but also the set point optimization for the engine and generator. When integrated as a RE into a typical European light duty vehicle, it provided a breakthrough consumption reduction relatively to existing plug-in hybrid electric vehicles (PHEVs) in the market in the charge sustaining mode. The very high efficiency of the power generation seems to compensate for the loss of efficiency due to the excess electricity production, which must be stored in the battery. The results indicate that indeed it is possible to have an efficient solution, in-line with the electric mobility sustainability paradigm, which can solve most of the shortcomings of current EVs, notably those associated with batteries (range, cost and charging time) in a sustainable way.

This work addresses the early stage calibration of a Formula SAE engine 1-D fluid dynamic model starting from limited experimental data. The availability of an engine model since the early stages of the development of a new Formula SAE vehicle allows to carry out preliminary analyses or ECU calibration. A few experimental tests have been executed at wide open throttle and variable engine speed. Then, a 1D thermo-fluid dynamic engine model has been developed starting from the geometry data of the engine. A vector optimization problem has been then solved to calibrate the engine model. In particular, the error minimization between numerical and experimental values of the torque in different engine operating conditions has been set as objective of the optimization process. Finally, starting from the results of the proposed calibration methodology, a decision-making criterion allowed the identification of a single optimal solution within the Pareto optimal front together with the related values for the set of calibration parameters. The results highlight how the proposed calibration procedure could be usefully adopted to set an early stage engine model which could be properly adopted to preliminarily detect the effects of geometric changes or control parameters variations on the main engine performance.

In this study, coke oven gas (COG), a by-product of coke manufacture with a high volumetric percentage of H2 and CH4, has been identified as auxiliary support and promising energy source in stationary internal combustion engines. Engine performance (power and thermal efficiency) and emissions (NOx, CO, CO2 and unburned hydrocarbons) of COG, pure H2 and pure CH4 have been studied on a Volkswagen Polo 1.4 L port-fuel injection spark ignition engine. Experiments have been done at optimal spark advance and wide open throttle, at different speeds (2000–5000 rpm) and various air-fuel ratios (λ) between 1 and 2. The obtained data revealed that COG combines the advantages of pure H2 and pure CH4, widening the λ range of operation from 1 to 2, with very good performance and emissions results comparable to pure gases. Furthermore, it should be highlighted that this approach facilitates the recovery of an industrial waste gas. This research is being supported by the Project “HYLANTIC”- EAPA_204/2016, which is co-financed by the European Regional Development Fund in the framework of the Interreg Atlantic program. Rafael Ortiz-Imedio thanks the Concepción Arenal postgraduate research grant from the University of Cantabria.

In this study, experiments were conducted on a four-cylinder spark-ignition engine to investigate the effects of iso-butanol additives in ethanol-gasoline blend on fuel properties, performance and emission characteristics of a SI engine. The engine tests were carried out at 50% wide open throttle and variations of engine speed from 3000 to 5000 RPM with an interval of 1000 RPM. The engine was fueled with base gasoline fuel, ethanol-gasoline blended fuel at 10% volume percentage of ethanol (E10) and three different fuel blends of iso-butanol additives; 5%, 10% and 15%, in E10 blended fuel denoted as E10B5, E10B10 and E10B15, respectively. Physicochemical properties tests were conducted in this study to evaluate the fuel heating value, kinematic viscosity and density, which have been selected due to their influences on engine performance and exhaust emissions. Results of heating value showed a decreasing pattern for the blended fuel samples compared with that of base gasoline fuel as E10, E10B5, E10B10 and E10B15 produced 2.33%, 3.14%, 5.06%, and 5.31%, respectively. However, as alcohol concentration increases in the blended fuel samples, the density and kinematic viscosity were both increased with maximum values of 0.767 g/cm3 and 1.15 mm2/s, respectively obtained for E10B15. In terms of engine performance, the blended fuel samples exhibited higher brake power than that of base gasoline fuel with mean increase of 7.71%, 10.21%, 10.89% and 11.54% for E10, E10B5, E10B10 and E10B15, respectively. Significant reduction in brake specific fuel consumption obtained with E10, E10B5, E10B10 and E10B15 by mean of 3.57%, 5.15%, 7.14% and 10.89% respectively, compared to base gasoline fuel. Noticeable improvement of brake thermal efficiency observed with the blended fuel at a maximum increment of 18.91% achieved by E10B15. High combustion temperature produced by the blended fuel samples have been contributed to the higher exhaust gas temperature. Accordingly, the emissions of carbon monoxide and hydrocarbon were all reduced; except for carbon dioxide and nitrogen oxide, with the addition of iso-butanol additive compared to those of ethanol-gasoline blend and base gasoline fuel.

YONTAR, AHMET ALPER/0000-0002-5453-5137; Dogu, Yahya/0000-0003-0474-2899 WOS: 000438692100013 In this study, a dual sequential spark ignition engine is separately tested either with gasoline or CNG at low and high loads. In addition, numerical engine analyses are performed by constructing a 1-D engine model in Ricardo-Wave software. Engine performance parameters in catalogue are generally given at full load conditions. However, during engine lifetime, vehicle engines rarely run at full load (wide open throttle) while engines work especially at the partial throttle openings. Engine characteristics (engine performance and exhaust emissions) are strong functions of throttle opening level. For this reason, determining engine characteristics at partial throttle openings at which engine mostly runs provides valuable information. In this study, partial throttle openings of 25% and 75% defined as low and high load conditions are examined for gasoline and CNG, as well. For this aim, the Honda L13A4 i-DSI (intelligent dual sequential ignition) engine was tested and engine characteristics were measured. This engine has unique features of dual sequential ignition with variable timing, asymmetrical combustion chamber, and diagonally positioned spark-plugs. Tests and numerical analyses were performed at specified low and high load conditions for gasoline and CNG by varying the engine speed from 1500 rpm to 4000 rpm with an increment of 500 rpm without excepting 2800 rpm. Engine characteristics were determined for the investigated parameters. Tests and 1-D model results are fairly matching each other. The average deviation between them is about 5.4%. Results show that the maximum torque for gasoline at 2800 rpm and 100% throttle opening reduced 12.6% and 26.3% for throttle openings of 75% and 25%, respectively. Compared to gasoline, CNG reduced the torque 15.6% and 19.6% for throttle openings of 75% and 25%, respectively. In general, CNG usage decreases all engine performance parameters (torque, power, volumetric efficiency, specific fuel consumption) and emissions (CO2, HC), except NOx formation. Scientific Research Coordination Unit of Kirikkale University, Kirikkale, Turkey; Yenmak Automotive Inc., Konya, Turkey This work was supported by the Scientific Research Coordination Unit of Kirikkale University, Kirikkale, Turkey; and Yenmak Automotive Inc., Konya, Turkey.

As vehicle interior noise control technology has significantly improved, focusing on vehicle interior sound quality has been suggested recently for improving user satisfaction. Research on the improvement of vehicle interior sound quality can be applied to the design of vehicle interior sound in order to achieve the desired image. For targeting the desired image, however, the subjective assessment of sound quality should be correlated with objective values because only quantitative and measurable data can be used for the control of vehicle interior sound. In this study, a model of psychoacoustic sportiness for vehicle interior sound was developed to target the “sporty” image of vehicles. The interior sounds of various vehicles were recorded under wide open throttle (WOT) acceleration condition, and subsequently modified to obtain additional sound samples. The loudness values of all stimuli were adjusted to the same value for excluding the impact of loudness on sportiness. In order to achieve subjective assessments of sportiness, a jury test was conducted, and sportiness was quantified using regression analysis. Therefore, the model for psychoacoustic sportiness was determined as a function of roughness, sharpness, and tonality. In a validity study, the sportiness estimated by this model was consistent with the observed sportiness of the additional jury test. Consequently, it was suggested that the sportiness model proposed in this paper is reliable and can be applied practically because the effect of loudness was excluded.

Syngas and biogas are two typical biofuels generated from biomass wastes through gasification and anaerobic digestion processes, which are considered to be the future fuels for IC engines. In this work, the utilization of biogas and syngas produced from horticultural waste in a premixed spark ignition engine was investigated. An experimentally validated KIVA4-based CFD simulation integrated with CHEMKIN was performed to evaluate engine performance fuelled by syngas and biogas under both single and blended-fuel modes. Effects of ignition timing, hydrogen content in syngas and methane content in biogas on both energetic and environmental performance have been studied. The indicated thermal efficiency (ITE) of syngas fueled engine at wide open throttle (WOT) condition under maximum brake torque (MBT) operation was found to be higher than that of biogas fueled engine, meanwhile, with much lower NOx emission. In addition, a comparison of the engine performance between the single and blended-fuel modes under different syngas mixing ratios was conducted in terms of ITE and NO X emission. The results suggest that the utilization of syngas and biogas under blended-fuel mode can not only maintain the MBT energetic performance under single-fuel mode, but also show its potential in reducing NOx emission and lessening the tendency of knock onset.

A single cylinder hydrogen fuelled internal combustion engine was experimentally evaluated and a model was developed. The optimized hydrogen engine developed a peak power of 4.8 kW @ 3600 rpm while operating under lean conditions. Lean operation in the equivalence ratio range of 0.47–0.59 resulted in low NOx emissions. The spark timing, equivalence ratio, and fuel injection timing were optimized to achieve high torque and low NOx emissions for different engine speeds at wide open throttle. A one-dimensional model was developed for the single cylinder engine, which was able to predict the trends in brake torque, brake power, brake thermal efficiency and NOx emissions for different engine speeds. It was found that the Woschni's correlation, which was originally developed for gasoline and diesel fuels under-predicted the convective heat transfer coefficient and the predicted coefficient was multiplied by a factor of 2.2 in order to simulate the actual heat losses with H2 fuelled IC engines. This is due to the high burning velocity as well as a low quenching distance of hydrogen flame which presumably results in higher cooling losses in a hydrogen engine. Using the model, a sensitivity analysis was further performed to study the effect of operating conditions such as engine speed, spark timing and equivalence ratio on the performance parameters and NOx emissions. The model was able to predict the reported trends of an increase in torque and a maximum in exhaust NOx concentration with an increase in the equivalence ratio. An increase in the exhaust NOx concentration with spark advance for all engines speeds was predicted. It was found that in order to achieve high torque, the spark energy must be provided closer to TDC for low speeds but should be advanced away from TDC for higher engine speeds.

A turbocharged Gasoline Direct Injection (GDI) engine fueled by n-butanol/gasoline blends is studied under the condition of wide-open throttle (WOT) in this paper. The effects of high n-butanol content (30% and 50% n-butanol by volume, i.e. Bu30 and Bu50) on the thermodynamic process and fuel efficiency of the GDI engine are discussed, as well as the engine emissions. Also, the results are compared with RON 93 gasoline and 10% ethanol/gasoline blended fuel (E10), which have been widely used in cars. The results show that high content of butanol addition can be realized in the GDI engine without any modification to its structure and control. Moreover, the maximum BMEP of the engine can increase to 1.99 MPa with Bu50. As compared with the gasoline and E10, high n-butanol/gasoline blends increase in-cylinder combustion pressure and pressure rise rate, promote ignition, and shorten burning duration. What is more, high n-butanol/gasoline blends improve combustion stability and decrease exhaust temperature, but they cannot deteriorate anti-knock quality. However, high n-butanol/gasoline blends increase Brake Specific Fuel Consumption (BSFC), and they decrease combustion efficiency and Brake Thermal Efficiency (BTE) at WOT. As for the engine emissions, high n-butanol/gasoline blends increase UHC and CO emissions but reduce NOx and CO2 emissions. The study implies that 0–50% butanol/gasoline blends can directly replace the existing engines fueled with regular RON 93 gasoline or E10.

In the present study, a single cylinder spark ignition (SI) engine is modified to operate with hydrogen gas with ECU (Electronic Controlled Unit) operated timely manifold injection system. Performance, emission and combustion parameters are studied at MBT (Maximum Brake Torque) spark timing with WOT (Wide Open Throttle) position. All trials are performed in the speed range of 1100 rpm–1800 rpm. Baseline observations are recorded with gasoline for comparison purpose. Results have shown that maximum brake power is reduced by 19.06% and peak brake thermal efficiency is increased by 3.16% in the case of hydrogen operation. Reduction in NOx emission is observed for hydrogen at higher engine speed. The maximum net heat release rate is two times higher and the peak cylinder pressure is 1.36 times higher for hydrogen as compared to gasoline at the engine speed of 1400 rpm.

Depletion of fossilised fuels coupled with stringent energy security has directed automotive researches to continuously investigate the use of alternative fuels in internal combustion engines. Within this subject, the research presented in this work is focused on using butanol as gasoline fuels substitution in a spark ignition engines. The present study reveals the combustion analysis specifically on cycle-to-cycle variations in spark ignition engines and performance characteristics of secondary butyl alcohol (sec-butanol) – gasoline blends at 5%, 10% and 15% by volume of sec-butanol in gasoline fuels. The engine performance characteristics was evaluated at 1000 to 4000 RPM with 50% of wide open throttle positions, while the in-cylinder pressure data were collected over 200 consecutive engine cycles for engine test at 3500 RPM. The indicated mean effective pressure time series is analyzed using the coefficient of variations and the wavelet analysis method. Comparative analysis of the performance characteristics showed that 2-butanol–gasoline blended fuel produced less brake power and brake mean effective pressure by 12.3%, 9.2% and 4.3%, for GBu5, GBu10 and GBu15, respectively, with regard to G100. From the wavelet power spectrum, it is observed that the long-term periodicities appear in gasoline fuels, while the short period oscillations become intermittently visible in blended fuels. Reduction of coefficient of variations occur as the additive of sec-butanol ratios increased, which agrees with the wavelet analysis results. Furthermore, the spectral power reduced with an increase in the additive ratio, indicating that the additive has a noticeable influence on reducing the cycle-to-cycle variations.

Natural gas is a cleaner burning alternative fuel that has the potential to widely replace conventional fuels. The use of Compressed Natural-Gas (CNG) in spark-ignited (SI) engines can reduce CO2 emissions by up to 20% compared with gasoline operation. Currently, all spark-ignited CNG engines for passenger vehicles are port-fuel injected (PFI). They suffer loss of peak torque and power due to a reduction in volumetric efficiency. Direct-Injection can overcome this drawback by injecting the fuel after intake valve closure, leading to significant improvements in torque output. In this experimental study, we present the effects of injection timing, before and after the inlet valve closure on combustion duration and engine thermal efficiency at low load and WOT (Wide Open Throttle) conditions. At low-loads, late-injection increases pumping losses compared to early-injection at a given loading condition but combustion is faster due to higher turbulence at the time of ignition. As a result, the thermal efficiencies are similar at these injection timings.

The flash boiling sprays in a single-cylinder optical gasoline direct injection (GDI) engine were studied using phase Doppler particle analyzer (PDPA) and high-speed photography. Initially, the factors which may influence the in-cylinder measurement reliability of PDPA were carefully examined under atmospheric conditions. Afterwards, engine experiments were conducted under idle and wide open throttle (WOT) conditions with the fuel temperature ranging from 20 °C to 90 °C. The results show that under idle operation, the spray collapsed towards the injector axis as the fuel temperature increased. At high fuel temperatures, the spray penetration increased so that the probability of fuel-wall impingement rises. As the fuel temperature increased from 20 °C to 60 °C, the AMD and SMD slumped by 43.6% and 33.2%, indicating the dramatic improvement in atomization quality. Concurrently, the droplet uniformity decreased sharply. As the temperature further increased to 90 °C, the AMD and SMD only dropped slightly, but the droplet uniformity became better. Under WOT operation, no distinct evidence of spray deformation was found except for the case at 90 °C. The AMD and SMD dropped steadily with the increase in fuel temperature, which is mainly attributed to the reduction in viscosity and surface tension. Besides, the droplet uniformity increased gradually along with the fuel temperature.

Lean operation is a promising approach to increase the engine efficiency. One of the main challenges for lean-burn technology is the combustion instability. Using a high laminar burning velocity fuel such as methanol might solve that problem. The potential of lean-burn limit extension with methanol was investigated through a comparison with conventional gasoline. In this work, a direct injection turbocharged SI engine was operated at wide open throttle (WOT), with the load controlled by a lean-burn strategy. The amount of fuel was decreased (or lambda increased) until the combustion became unstable. For methanol, the lambda limit was about 1.5, higher than the lambda limit for gasoline which was only about 1.2. The brake thermal efficiency for methanol increased as lambda increased and reached its peak at ~41% in a lambda range of 1.2-1.4. Then, the efficiency decreased as lambda increased. The increase of lambda also causes a change in the combustion process, e.g. prolonged flame development period (CA0-10). The relationship between the combustion characteristics and the combustion instability of methanol under lean-burn condition has not been reported previously. Values for the CA0-10 duration and the laminar burning velocity were searched for, able to define the combustion stability limit for the WOT operation with methanol. The laminar burning velocity was calculated using a previously developed correlation, with the unburned gas temperature and residual mass fraction derived from a three-pressure analysis simulation. A CA0-10 duration of 26.5 degree crank angle and a laminar burning velocity at ignition timing of ~0.4 m/s could be used to represent the combustion stability limit (5% coefficient of variance of indicated mean effective pressure). A longer CA0-10 and a smaller laminar burning velocity indicate an unstable combustion of methanol at WOT. At throttled conditions, those limits could not be employed to represent the instability limit for methanol combustion.

As part of the U.S. Environmental Protection Agency’s (EPA’s) continuing assessment of advanced light-duty automotive technologies in support of regulatory and compliance programs, a 2018 Toyota Camry A25A-FKS 4-cylinder, 2.5-liter, naturally aspirated, Atkinson Cycle engine with cooled exhaust gas recirculation (cEGR) was benchmarked. The engine was tested on an engine dynamometer with and without its 8-speed automatic transmission, and with the engine wiring harness tethered to a complete vehicle parked outside of the test cell. Engine and transmission torque, fuel flow, key engine temperatures and pressures, onboard diagnostics (OBD) data, and Controller Area Network (CAN) bus data were recorded. This paper documents the test results under idle, low, medium, and high load engine operation. Motoring torque, wide open throttle (WOT) torque and fuel consumption are measured during transient operation using both EPA Tier 2 and Tier 3 test fuels. The design and performance of this 2018 2.5-liter engine is described and compared to Toyota’s published data and to EPA’s previous projections of the efficiency of an Atkinson Cycle engine with cEGR. The Brake Thermal Efficiency (BTE) map for the Toyota A25A-FKS engine shows a peak efficiency near 40 percent, which is the highest value of any publicly available map for a non-hybrid production gasoline internal combustion (IC) engine designed to run on 91 RON fuel. Further improvement is possible by application of fixed discrete or full continuous cylinder deactivation, both of which are currently in production on other engines.

The current engine manufacturers are inclined to develop engine with higher compression ratio to increase its efficiency in accordance with the availability of gasoline in the market. Meanwhile, gasoline fuels distributed in Indonesia have research octane number (RON) between 88 to 98, i.e., gasoline 88, gasoline 92, and gasoline 98. In order to increase the octane number of gasoline, an ethanol-gasoline blend can be one of the alternatives since ethanol has higher octane number than gasoline. Nevertheless, gasoline blended with ethanol will reduce the heating value of the fuel mixture. Due to many choices of gasoline and various octane ratings available in the market, prices become the main consideration to buy specific gasoline instead of considering octane number. The objective of this research is to analyze the influence of ethanol-gasoline blend (E5) with various octane ratings on the performance of 150cc, single cylinder, four-stroke gasoline engine, with fix compression ratio. The tests were carried out using AVL dyno for engine testing which performed at maximum load (wide open throttle) and diverse engine speeds of 1000, 1500, and 2000 rpm. For each engine speed variation, we measured the engine power, torque, air-fuel ratio (AFR) and specific fuel consumption (SFC). The results indicated that in general, a higher octane number of ethanol-gasoline blend (E5) will give benefits in the form of an increase of engine power and torque, and a decrease in the value of SFC.

One of the most important parameters for engine performance is a fuel that is used, the quality of its fuel as well as the value of the octane number. Gasoline fuel that distributed in the markets in Indonesia has a lot of value of octane number. For example, there are Gasoline 88, Gasoline 92, and Gasoline 98. These three types of fuel have different octane numbers and different prices. Most people just consider the price in its use without regard to existing specifications. This paper investigates the effect of using Gasoline with different values of octane number on performance and exhaust pollutant emissions of a four strokes 150 cc single cylinder spark-ignition (SI) engine without any modifications, in AVL dyno engine test. Experiments were conducted at maximal load or wide open throttle (WOT) and different engine speeds ranging from 1000 to 2500 rpm. Engine power, torque, specific fuel consumption and exhaust pollutant emissions were measured during each experiment.

The article examines the performance of a 4-stroke gasoline engine using Bio-fuel (Ethanol). The research work was carried out on a SOLTEQ engine test bed available in university in Thermodynamics laboratory. In this study an ordinary gasoline engine was fixed on test bed. Several modifications to external parts of the engine were made to fix it on the bed such as base frame, suction port, exhaust port and oil temperature indicators. To asses engine performance the experiment setting used gasoline with 5 different blends of ethanol such as E0 (100% gasoline), E5 (95% gasoline, 5% ethanol), E10 (90% gasoline, 10% ethanol), E15 (85% gasoline, 15% ethanol) and E20 (80% gasoline, 20% ethanol). While the engine performance was evaluated at operating parameter called wide open throttle (WOT). Different charts were established to compare results. The results obtained from analysis showed significant deviations in performance curves at different fuel grades. These results were quite useful especially for utilizing ethanol additives with gasoline in ordinary gasoline engines.

This paper presents the results of an investigation on the performance characteristics of a small spark ignition (SI) engine fueled by liquefied petroleum gas (LPG) to be compared with gasoline fueled. The LPG delivery systems used was fuel injection while carburetor was used for gasoline. In the experiment, wide open throttle (WOT) was run on a four stroke single cylinder engine that was coupled to a 20 kW generator dynamometer to measure the engine performance such as engine torque, and fuel consumption. Others parameters included are brake power (BP), brake specific fuel consumption (BSFC) and brake thermal efficiencies (BTH). The results were compared, analyzed and suggestions were made for modification for further improvement of using LPG in a small SI engine. It was found that the engine fueled by LPG had a lower performance compared to the gasoline fueled engine.

Energy shortages based on current global demand requires the technological solutions to increase fuel conversion efficiency in internal combustion engines. In this context, lean combustion is a relevant technique for increasing thermal efficiency and reducing pumping losses. Another strategy to reduce engine pumping losses is operating without restrictions imposed by the throttle valve, as in wide open throttle (WOT) conditions, when load is regulated by fuel injection. This technique, already used in diesel engines, is not currently used in Otto cycle engines due to limitations of operating outside fuel stoichiometry. However, lean operation is increasingly feasible with the development of technologies such as the prechamber ignition system (PCIS), which provides high ignition energy and mixture turbulence, improving combustion. The present work compares the effects of mixture enleanment in an Otto ethanol multicylinder engine using a prototype PCIS with the original ignition system running stoichiometrically. The results indicate that the use of PCIS enables the engine load control by variations of lambda, extending the lean limit to λ = 1.35 and λ = 1.6 with the homogeneous and stratified systems respectively. The use of PCIS in SI engines could increase the efficiency of stationary generator sets and hybrid vehicles, also reducing NOx, CO and CO2 engine-out emissions at partial loads.

Opposed rotary piston (ORP) engines have advantages of high power density, few moving parts, and smooth operations, which makes ORP engines as potential power sources for hybrid vehicles and range extended electric vehicles. Ignition timing significantly affects the performance of spark ignition engines including fuel economy and emission factors. In this paper, the effect of ignition timing on the engine performance was investigated using a three-dimensional numerical simulation method. The results indicated that crank angle corresponding to the peak in-cylinder pressure over the ignition timing of −8.2° crank angle (CA) was advanced compared with other cases having earlier ignition timing; however, the crank angle of peak heat release rates were retarded. Start of combustion was delayed by retarding the ignition timing and increasing engine speed; combustion duration over the ignition timing of −18.9° CA ~ −11.1° CA changed slightly for individual engine speed. Indicated specific fuel consumption (ISFC), being hardly dependent on the ignition timing, was less than 74 g/(kW·h) over the ignition timing of −17.3° CA ~ −11.1° CA, where indicated thermal efficiency was approximately 41%, 39% and 35% for 1000 RPM, 3000 RPM and 5000 RPM respectively. When ignition timing was later than −11.1° CA, ISFC and indicated thermal efficiency were deteriorated seriously. Nitrogen oxides (NOx) emission factors increased with engine speed over early ignition timing; however, they were inverse for late ignition cases. Higher engine speed and retarded ignition timing led to higher percentage of exhaust energy in fuel chemical energy.

Under the stress of environmental pollutions and fossil fuel consumption caused by on-road transport, hybrid vehicles are attracting much attention. Opposed rotary piston (ORP) engines are a promising power source for hybrid vehicles, due to their compact designs and high power density. In this paper, combustion and emission characteristics of a turbocharged ORP engine fuelled with hydrogen were investigated to evaluate the overall performance of this engine. The results indicated that volumetric efficiency of this ORP engine was higher than 89.0% for all the given cases. Peak in-cylinder pressure was in the range of 51.0 ~ 69.0 bar; and 4000 RPM scenario had the maximum value, being benefitted from high intake temperature and pressure, and high volumetric efficiency. Combustion duration of this engine ranged 27 ~ 43° crank angle (CA), and combustion phase happened at 7.5 ~ 13°CA after top dead centre (TDC). Peak nitrogen monoxide (NO) formation rates were corresponding to 5 ~ 13°CA after TDC; accumulated NO decreased slightly after reaching the peak value for low engine speed conditions. Discharge pressure at the start of the exhaust stroke was higher than 6.0 bar, especially for 5000 RPM case whose value was approximately 11.0 bar. This ORP engine presented excellent torque characteristics, and the maximum indicated power density was approximately 104.0 kW·L−1 which was much higher than turbocharged four-stroke reciprocating engines fuelled with gasoline.

Opposed rotary piston engines are characterized by high power density, which makes them as an ideal power source for hybrid vehicles and range extended electric vehicles. Hydrogen applications can fully exhibit the merits of opposed rotary piston engines, and achieve zero carbon dioxide emissions; however, the applications seriously worsen the nitrogen oxides emissions. In this investigation, lean-burn was adopted to achieve low nitrogen oxides emissions using a three dimensional numerical simulation approach. The results indicated that engine speed of 3000 r/min presented the highest in-cylinder pressure during combustion among the given scenarios, and the pressure over 3000 r/min depended more on the equivalence ratio than that of 1000 r/min and 2000 r/min. Heat release rates were very sensitive to low equivalence ratio. Combustion duration over the equivalence ratio of 0.8 was the shortest among 1000 r/min cases; however, it decreased with equivalence ratio for 2000 r/min and 3000 r/min. Heat loss rates through cylinder walls increased significantly with engine speed, meanwhile they were more dependent on the equivalence ratio over higher engine speed. Maximum nitrogen monoxide formation rates over 3000 r/min occurred slightly earlier than those of 1000 r/min and 2000 r/min. Equivalence ratio of 0.8 showed the highest indicated thermal efficiency over corresponding engine speed, and nitrogen dioxide emission factors were quite low over the equivalence ratio of 0.7 for the given engine speed.

This paper experimentally investigates the effect of hydrogen addition on the lean burn capability of an ethanol-fuelled Wankel rotary engine at Wide Open Throttle (WOT) operating conditions in order to observe the resultant engine economy and the hydrocarbon emissions. During the tests, a monorotor Wankel engine operating at 3000 rpm was modified to run on an ethanol–hydrogen blend with 0% and 5% hydrogen energy fractions in the intake. The excess air ratio was varied from 1.7 to the Ultra-Lean Operating Limit (ULOL) of a specified hydrogen–ethanol mixture. With hydrogen addition, the test results show that the ultra-lean operation limit of pure ethanol fuelled Wankel engine was extended and the engine stability was enhanced. Moreover, the engine fuel economy was increased and Hydrocarbons (HC), Carbon Monoxide (CO) and Carbon Dioxide (CO2) emissions were reduced after hydrogen addition.

A few cases of the sudden unintended acceleration have been reported over the last few years [1-11] and some of them seemed to be somewhat related to an electronic throttle control (ETC) system [11,12]. In this experimental study, efforts were made to reproduce the cases of sudden unintended acceleration possibly related to the ETC. Typically, an ETC of the engine is managed based on signals from airflow sensor, throttle position sensor and acceleration pedal sensor. With this typical sensor configuration in mind, these sensor signals were checked for noise levels. However, none of them showed any clear relationship with the sudden unintended acceleration mainly due to the robustness of the ETC logic software. As an alternative approach, supply voltage to an engine control unit (ECU) was tempered intentionally to observe any clues for the incidents. The observed results with the supply voltage drop and fluctuation tests were rather astonishing. The throttle valve position went all the way up to 100% for around one second when the battery voltage plunged down to 7V periodically despite that the acceleration pedal position was kept steady. As an effort to confirm the case, multiple tries were made systematically on a chassis dynamometer as well as on the test road. In this paper, detailed procedures and findings are reported accordingly.Copyright © 2016 Elsevier Ireland Ltd. All rights reserved. Language: en

This paper shows the effect of 0, 5, 10 and 15 % of hydrogen by energy in compressed natural gas during lean burn and stoichio. burn combustion. All trials are performed at wide open throttle position on 3-cylinder, water-cooled 796 cc S.I engine using sequential port fuel injection system at equivalence ratio of 0.7 and 1.0. Carbon-based emission decreased with increase in hydrogen addition. MBT spark timing increased with increase in speed and decreased with increase in equivalence ratio. At 12°CA spark advance and 2500 rpm, 5 % hydrogen addition shows rise in brake thermal efficiency with optimum NOx. NOx emission increased with increase in hydrogen addition and decreased with MBT spark timing. Heat release rate and maximum rate of pressure rise increased remarkably with 5 % hydrogen addition due to increase in burning velocity. Maximum brake thermal efficiency of 25 % is observed for 5 % hydrogen addition with increase in power output at stoichiometric condition.

In this paper, the effect of hydrogen addition to ethanol in a monorotor Wankel engine at wide open throttle position and in an ultra-lean operating regime was experimentally investigated. For this aim, variation of hydrogen enrichment levels on the ethanol engine performance and emissions were considered. Experiments were carried out under a constant engine speed of 3000 rpm and fixed spark timing of 15 °BTDC. The test results showed that hydrogen enrichment improved the combustion process through shortening of the flame development and flame propagation periods and reducing the cyclic variation. Furthermore, the reduction of burn duration with the increase of hydrogen fraction enhances the thermal efficiency, reducing the brake-specific energy consumption, as well as reducing the unburned hydrocarbons emissions of the Wankel engine.

In this paper, an experimental investigation of the effect of hydrogen enrichment on a gasoline Wankel engine's Lean Operation Limit (LOL) was performed. A monorotor Wankel engine operating at 3000 rpm and wide open throttle was modified to run on gasoline and hydrogen blends. Excess air ratio varying from stoichiometric mixtures to the engine lean burn limit with 0%, 3% and 6% of hydrogen energy fractions in the intake were investigated. The experimental results proved that adding hydrogen to gasoline extends the original engine LOL while improving the engine stability. An increased thermal efficiency and reduced burn duration, brake specific energy consumption, and HC, CO and CO2 emissions were observed with hydrogen enrichment. Furthermore, the extension of the engine LOL with hydrogen addition could potentially control the NOx emissions of a gasoline Wankel engine to very low levels without using a three-way catalytic converter.

This article is aimed at exploring syngas as an alternative fuel for the modern gas engines. It presents the experimental results on the effect of start of injection on combustion, performance and emissions of a direct-injection spark-ignition engine powered by syngas of H2/CO composition. The engine was operated with wide open throttle at minimum advance to achieve maximum brake torque. Two different start of injections were selected to represent before and after inlet valve closing and the excess air ratio (λ) was set at 2.3. The engine operation at start of injection = 120° before top dead center was found to be best for combustion and performance at speed up to 2100 r/min. At engine speed higher than 2100 r/min, this start of injection does not permit maximum performance due to injection duration limitation. Hence, early injection at start of injection = 180° before top dead center was adopted at higher speed with better combustion and performance. Therefore, best performance of syngas in direct-injection spark-ignition engine could be attained by setting start of injection at 120° before top dead center for lower speeds and at 180° before top dead center for speed greater than 2100 r/min. Even though fast combustion of syngas suggested late injection for better combustion, performance and emissions, its lower calorific value resulted in operational limitations for direct-injection system particularly at higher speeds maintaining air–fuel ratio close to the stoichiometry.

This article experimentally investigates the effect of spark timing on performance and emission characteristics of high-speed spark-ignition (SI) engine operated with different hydrogen–gasoline fuel blends. For this purpose, the conventional carbureted SI engine is modified into an electronically controllable engine, wherein an electronically controllable unit was used to control the ignition timings and injection duration of gasoline. The tests were conducted with different spark timings at the wide open throttle position and 3000 rpm engine speed. The experimental results demonstrated that brake mean effective pressure and engine brake thermal efficiency increased first and then decreased with the increase in spark advance. Peak cylinder pressure, temperature and heat release rate were increased until 20% hydrogen addition and with increased spark timings. NOx emissions were continuously increased with the increment in both spark timings and hydrogen addition, whereas hydrocarbon emissions were...

This paper shows the effects of equal spark timing on hydrogen enriched compressed natural gas (HCNG) fuel blends for three cylinder SI engine using sequential port fuel injection system. All trial are performed at fixed compression ratio of 9.2 with varying fuel blends of 0, 5, 10 and 15 % hydrogen by energy with CNG at wide open throttle (WOT) position. Equal spark timing (EST) shows reduction in power output with increase in NO x emission compared to maximum brake torque (MBT) spark timing for all fuel blends. Brake thermal efficiency reduced from 23.08 % for MBT spark timing to 17.94 % for EST at 2500 rpm. Spark timing is kept constant for all fuels blends, in order to assess their interchangeability on SI engine. The maximum peak pressure for 5 % hydrogen addition is observed to be 29.36 bar occurred at 24°ATDC. At lean condition COVIMEP and heat release rate increased with EST compared to MBT spark timing.