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The transport sector has been considered as one of the primary reasons of the situation of rapid climate change. This paper aims to determine the real-world driving characteristics of motorcycles (MCs) in Hanoi to support further studies on MCs' emissions and fuel consumption. An infrared sensor was installed directly on the wheel of the test MC to record the revolving speed of the wheel. After that, the instantaneous speed of the test MC was calculated and pre-processed. Only about 0.82% of total data points were detected as error points and processed. Twenty-five driving kinetic parameters were calculated based on the processed instantaneous speed data to reflect the real-world driving characteristics of MCs in Hanoi. The change in the real-world driving characteristics of MCs in Hanoi from 2009 to 2020 has been recognized, particularly the share of the time proportion in different operation modes. The time proportion of the acceleration, deceleration, cruising, creeping, and idling modes in the real-world driving characteristics of MCs in Hanoi is 35.51%, 34.52%, 11.23%, 12.01%, and 7.13%, respectively. The average speed of MCs in Hanoi is about 20.49 kph. The VSP distribution in the real-world driving data of MCs in Hanoi is concentrated mainly at the bins relating to idling and low speeds.

This paper presents the study results on stress and deformation of the piston crown of a biogas engine converted from a conventional diesel engine using dedicated software. The original diesel engine was modified to reduce the compression ratio to suit biogas fuel. The original engine's combustion chamber and compression ratio were changed by modifying the piston crown to a heron type. The parameters of in-cylinder pressure and temperature were determined by the thermodynamic simulation software AVL Boost. Research results show that the in-cylinder pressure decreased compared to diesel when using biogas fuel, but the temperature increased. The infinite element method-based software was used to simulate the effects of mechanical and thermal load on stress and deformation on the piston crown of the biogas engine. As modeling with maximum pressure and temperature, the maximum stress on the piston crown was 3.425x109 N/m2 and 4.224x109 N/m2 for diesel and biogas. However, the maximum deformation in the biogas case was lesser than diesel, 0.3037 and 0.4186 mm. The minimum safety factor was 0.1012 and 0.0891 for diesel and biogas models, respectively.

This study aims to develop the models of emission and fuel consumption during idling of motorcycles (MCs) in Hanoi, including the unsteady and steady idling stages. Five MC models commonly used in ...

This research shows the analysis forces on the components of the V-12 engine. To complete this research, the thermodynamic combustion process analysis of a V-12 engine was performed to calculate th...

This research conducted the effect of different ethanol blends in a conventional gasoline engine under various load and speed conditions for its performance and emission characteristics. The experiment was tested on the test motorcycle designed initially to run by gasoline fuel. The experimental procedure was performed in the motorcycle testbed equipped, measuring power, fuel consumption, and exhaust emissions. NOx and HC emissions of the test vehicle using ethanol blends are lower than gasoline. However, NOx emissions have an opposite trend; they increased approximately 7.4% with E5, 12.3% with E10, and 18.51% with E20 due to the temperature increase. Furthermore, the ethanol contents provide the leaning effect to enhance the air-fuel equivalence ratio to a more excellent value and result in the burning closer to stoichiometric. As a result, improved combustion and increased power output are possible.

This paper conducted an experimental study on the performance and emission characteristics of bi-fuel gasoline-liquefied petroleum gas (LPG) for in-used fuel-injected motorcycles. By using an electric bi-fuel controller, the original engine can operate smoothly on either conventional fuel or alternative one. The performance was evaluated by comparing the brake power at the wheel of the test motorcycle with a different kind of fuel. The carbon balance method was used to determine the fuel consumption from instantaneous emission levels measured by the constant volume sampler system. The pollutant level was measured following the driving cycle test ECE R40. The exhaust emission of HC, CO, and NOx of the test vehicle fueled by LPG reduces 69.94%, 47.89%, and 46.48% compared to gasoline. The average fuel (kg/100km) and energy (MJ/100km) consumption were reduced by 14.78% and 12.84%, respectively. In contrast, average fuel consumption in l/100km increased by 11.10%. The degradation in engine performance was observed. The best brake power at the wheel was reduced by 19.42% on average. The developed bi-fuel system could be a feasible solution for environmental protection, fuel economy and guarantee the long life of currently used motorcycles in Vietnam's current context.

Reduction of environmental pollution and fossil fuel dependence are two worldwide concerned problems. Many research projects have addressed many solutions for these issues, in which, the trend of using bio-fuel has been widely studied and applied. Ethanol, a kind of biofuel has been used on motorcycle engines, which use carburetor system, to replace conventional gasoline. Ethanol is characterized by a higher heat of vaporization value than gasoline, thus the reduction of the intake manifold temperature which effects engine performance especially at cold starting and idling conditions. In this study, a certain amount of exhaust gas was recirculated to heat the intake manifold, thereby increasing intake mixture temperature, to improve the combustion process of the engine, results in improvement of engine performances. In experiment, an exhaust gas heating transfer system was designed to recirculate a partial mass of exhaust gas to transfer heat energy to the intake manifold of the test motorcycle fueled with ethanol. The experimental results show that, with the exhaust gas heating transfer system, the specific fuel consumption of the test engine improve remarkably and some gaseous emissions tend to be reduced; in addition, hot starting ability of the test engine with the heating transfer system improves significantly compared to the case of without the system.

This paper presents an experimental study of the performance and emission characteristics of a port fuel injection spark ignition engine modified to fuel by compressed natural gas (CNG). Consequently, the original fuel supply system of the test engine was modified to flexibly run on either gasoline or CNG. The experiment was conducted to compare operating parameters of the test engine fueled by gasoline and CNG with the same air excess ratio (λ). The study results showed that when fueled by CNG, the brake power of the test engine decreases up to 19% and the brake specific energy consumption (BSEC) increases 14%. However, the exhaust emissions of the test engine fueled by CNG are enhanced dramatically. Indeed, CO2 emissions decrease up to 50%, NOx emissions decrease 20%, especially, CO and HC emissions reduce up to 90% and 96%, respectively. For the application of CNG in real-world conditions for in used vehicles, it is recommended that we have to concentrate to solve the problem related to the low power and high fuel consumption of the original engines fueled by CNG.

Using the laboratory-based fuel consumption models for predicting real-world fuel consumption requires the measurement of data under certain conditions to obtain high accuracy of predicted result. Therefore, it is necessary to develop a logging device for measuring the real-time fuel consumption and speed of vehicle on the road. This article presents a study on developing the on-board data logging device to collect real-world data of fuel consumption and speed for motorcycles with the update rate of 1 Hz. The instantaneous speed of the motorcycle was determined based on the rotational speed of the wheel and the wheel radius. Another module was used to determine the instantaneous fuel consumption rate (FR) though measuring the duration injection pulse. The relationship between the duration injection pulse and the injected amount of fuel was established with high correlation coefficient of 0.997. In addition, a filter was designed to remove noise in the dataset collected using the data logging device. The random errors in the speed and the FR profiles were detected and replaced, the percentage of these errors is 1.8% and 2.4%, respectively. The developed method is a precise one for transient fuel consumption and speed measurement. In chassis dynamometer test, the average deviation between steady speed measured by the chassis and the data logging device is only approximately 0.35%. At transient state, the biggest deviation between these two datasets is less than 3.5%. The average FR at steady speed measured by the developed method is slightly different from the one measured by the carbon balance method. The difference is 0.9%, 2.5%, and 0.25% at the speeds of 30 km/h, 50 km/h, and 70 km/h, respectively. Following the transient test cycle, the fuel consumption measured by the developed method is 4.35% lower than that determined by the carbon balance method.

Compressed Natural Gas (CNG) has been applied worldwide for in-used engines, especially CNG engines that are converted from the conventional engines. However, it encounters the problem related to the low power and high fuel consumption of the conventional engine fueled by CNG. This paper presents an experimental study on performance enhancement of a CNG engine converted from the spark-ignition engine by the implementation of fuel additive Maz 100. In experimental work, a fuel additive supplying system was developed to impose a certain amount of fuel additive to the intake manifold of the test engine. The study results show that when using Maz 100, the brake power of the test engine improves approximately 6.75% on average at full load conditions. The brake specific fuel consumption (BSFC) reduces 6.49% on average at full load and 3.53% on average at partial load condition. In addition, besides the benefit of performance enhancement, exhaust emissions of the test engine in the case of operating with fuel additive have changed considerably. Particularly, the CO emission reduces 36.1% at full load and 18.4% on average at partial load conditions. The HC emission reduces 37.1% at full load and 35.0% on average at partial load conditions. The NOx emission increases slightly in low-speed regimes and reduces in high-speed regimes when the engine operates at the full opened throttle condition. At partial load condition and speed of 3000 rpm, the NOx emission reduces 22.6% on average. Implications: This paper presents a solution for performance enhancement and emission reduction of natural gas engine by using fuel additive. Performance and emission characteristics of the natural gas engine fueled with fuel additive have been assessed in the laboratory. The performance of the test engine improves remarkably. The brake power of the test engine improves approximately 6.75% on average at full load conditions when the engine operates with fuel additive. The brake specific fuel consumption reduces 3.53% on average at partial load condition. The emission of pollution has different trends. The CO and HC emission reduces at testing conditions. The NOx emission increases slightly in low-speed regimes and reduces in high-speed regimes when the engine operates at the full opened throttle condition. The implementation of fuel additive is a potential solution for power improvement and emission reduction of natural gas engine.

The paper presents a simulation and experimental study on using bi-fuel gasoline - liquefied petroleum gas (LPG) for currently used fuel-injected motorcycles in Vietnam. Consequently, an innovative fuel supply system was designed to make the original gasoline motorcycles can flexibly operate on either gasoline or LPG. In this research, simulation processes were conducted by using a dedicated software analysis tool to optimize the operation process of the fuel system in order to maintain its stability and efficiency based on the characteristics of each type of fuels. Meanwhile, the original fuel supply system of the test motorcycle will be modified in the experiment by developing the second Electronic Control Unit (ECU) to control LPG quantity supplied for the one. The results showed that the test motorcycle well operated on either gasoline or LPG on the new design. In addition, when running on LPG the specific fuel consumption and exhaust emissions of the test motorcycle were reduced significantly. The investigation suggests that the old generation of fuel-injected motorcycles can be run flexibly on bi-fuel in order to reduce the fuel consumption and exhaust emissions.

In Vietnam, the primary energy consumption has increased rapidly over the past decade, and the government promotes the vehicle emission standards and the development of renewable energy to complement fossil fuel. In concert with the government policy on these problems, motorcycle manufacturing companies have applied new technologies to reduce pollution emissions and fuel consumption. However, these technologies been applied only to new vehicles before selling on the market; as a result, they cannot solve the primary inducement due to a large quantity of used motorcycles in Vietnam. This research has developed a new fuel system that enables used gasoline motorcycles to operate on 100% ethanol, a type of renewable energy, which is widely used as a proportion in spark ignition engines. The research results showed satisfactorily that the motorcycles retrofitted the new fuel system can reduce significantly emission and fuel consumption.

In this paper, the environmental efficiency of the bus rapid transit (BRT) in Hanoi was analyzed through estimating the co-benefits of air quality, climate and health. First, the real-world driving data, instantaneous velocity versus time, in the city was collected using the global positioning system (GPS) technology with the signal update of 1 Hz. Then, a data processing procedure consisting of nine steps was applied to remove errors and to smooth the GPS data. After that, the processed GPS data was used to develop the typical driving cycle for BRT in Hanoi based on the Markov chain theory. Emission factors of air pollutants including CO, CO2, VOC, NOx, SO2, and PM10 were determined based on the developed driving cycle with the use of the International Vehicle Emissions (IVE) model. The health effect was estimated using the AirQ+ model. It is found that, compared to the regular buses, deploying the BRT in Hanoi can reduce the emissions of air pollutants 17.3–22.6 % and the amount of CO2eq emission up to 22.4 %. It is also indicated that at least 4.8 % of prevalence of bronchitis symptoms in asthmatic children aged 5–14 years, and 2.4 % of total mortality due to all causes except accidents in aged 30+ years in Hanoi can be reduced through deploying the BRT. Although the average speed of the current BRT in Hanoi is only 1.3 times higher than the regular bus, it could bring to significant benefits in terms of environment and health.

In developing countries, a large number of old-generation diesel engines without turbochargers have become popular, and they are the main sources of power in the area of transportation. However, these types of engines have many disadvantages, such as low power and efficiency as well as a large amount of exhaust emissions. Meanwhile, these countries cannot immediately cease their image for them due to the limitations of budge for industry development. In this research, we promote a method to improve the efficiency of operation of old model diesel engines used for agricultural machines in Vietnam by retrofitting turbochargers. Consequently, the operating characteristics of retrofitted turbocharger engines have been performed both experimentally and using simulation. The research results show that the engine performance and exhaust emission improve dramatically when retrofitting suitable turbochargers corresponding with the engines. However, after turbocharging, we also increase the thermal and mechanical stresses of engines. The results indicate that we need to perform in detail to find the best solution for the stable operation of engines.