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In this study, the effect of dimethyl ether enriched air (DMEA) on pollutants and performance characteristics a diesel engine was evaluated. The combustion parameters have been evaluated by simulat...

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 ...

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.

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.

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.