Zhuoyao He

Bio: Zhuoyao He is an academic researcher from Shanghai Jiao Tong University. The author has contributed to research in topics: Combustion & Ignition system. The author has an hindex of 9, co-authored 41 publications receiving 258 citations.

In-cylinder thermochemical fuel reforming (TFR) in a spark-ignition natural gas engine

Abstract: This experimental study demonstrates the potential to apply the thermochemical fuel reforming (TFR) concept to simultaneously reduce emissions and improve brake specific fuel consumption in a spark-ignition natural gas engine. CH 4 , H 2 and CO are the major components of TFR exhaust gas over a range of rich equivalence ratios. A numerical analysis is conducted to illustrate the chemical reaction pathways for H 2 and CO formation, which occurs in the cylinder during the TFR process. The main reaction pathways for H 2 and CO formation under 3 modeling conditions (20%, 50% and 80% fuel consumed) are different from each other. According to the experimental analysis, thermochemical fuel reforming gas improves combustion performance and accelerates the burn rate in every phase of the natural gas engine. Combustion stability, brake thermal efficiency, brake specific fuel consumption (BSFC), brake specific hydrocarbon (BSHC) and brake specific carbon monoxide (BSCO) emissions can also be improved by TFR. The brake specific oxides of nitrogen (BSNO x ) emissions for natural gas engines, combined with a TFR system, are still lower than those of an original natural gas engine in the same operation mode. Thermochemical fuel reforming has been shown to be effective in simultaneously reducing emissions and improving thermal efficiency for a spark-ignition natural gas engine. Furthermore, a 1.2 equivalence ratio for cylinder 4 (TFR cylinder) can be recommended in future research on TFR optimization, based on BSFC and combustion stability.

Engine combustion and emission fuelled with natural gas: A review

Abstract: Natural gas (NG) is one of the most important and successful alternative fuels for vehicles. Engine combustion and emission fuelled with natural gas have been reviewed by NG/gasoline bi-fuel engine, pure NG engine, NG/diesel dual fuel engine and HCNG engine. Compared to using gasoline, bi-fuel engine using NG exhibits higher thermal efficiency; produces lower HC, CO and PM emissions and higher NOx emission. The bi-fuel mode can not fully exert the advantages of NG. Optimization of structure design for engine chamber, injection parameters including injection timing, injection pressure and multi injection, and lean burn provides a technological route to achieve high efficiency, low emissions and balance between HC and NOx. Compared to diesel, NG/diesel dual fuel engine exhibits longer ignition delay; has lower thermal efficiency at low and partial loads and higher at medium and high loads; emits higher HC and CO emissions and lower PM and NOx emissions. The addition of hydrogen can further improve the thermal efficiency and decrease the HC, CO and PM emissions of NG engine, while significantly increase the NOx emission. In each mode, methane is the major composition of THC emission and it has great warming potential. Methane emission can be decreased by hydrogen addition and after-treatment technology.

HCNG fueled spark-ignition (SI) engine with its effects on performance and emissions

Abstract: The usage of natural gas in internal combustion engines involves various difficulties, like weak lean-burn ability, low flame speed and ignitability, which demand deep studies for its usage in IC engines. For compressed natural gas (CNG) in SI engines, there is an engine efficiency sacrifice at low loads and high levels of hydrocarbon (HC) and carbon monoxide (CO) emissions which cannot be solved without using after-treatment equipment. This equipment, however, is very expensive. Therefore, an additional fuel can enhance the characteristics of the combustion of natural gas, which can be added in the intake charge. Hydrogen is an effective gas for enhancing the flame rate regarding combustion in an SI-CNG engine, in addition to increasing engine stability. Small amounts of hydrogen improve performance and reduce exhaust emissions. Thus, a number of investigators have carried out research studies on SI engines with different ratios of HCNG. This paper is comprehensive overview of CNG, H 2 and HCNG blends. The main topics discussed consist of the combustion fundamentals of natural gas, hydrogen and hydrogen-natural gas mixture. Natural gas and hydrogen usage as fuels and their characteristics have been analysed. The storage of hydrogen and HCNG is still challenging researchers and, therefore, their storage has been taken into consideration. Moreover, a comprehensive review has been performed of HCNG blends in order to understand the effect of hydrogen enriched CNG on performance and the emissions of SI engines. The combustion characteristics of HCNG engines are strongly dependent on the conditions of the engine. The air-fuel ratio, the time of injection, the compression ratio and speed play a major role in blending HCNG in an SI engine and have been discussed in this article.