Chaohe Yang

Bio: Chaohe Yang is an academic researcher from China University of Petroleum. The author has contributed to research in topics: Gasoline & Octane rating. The author has an hindex of 1, co-authored 2 publications receiving 1 citations.

A Compendium of Methods for Determining the Exergy Balance Terms Applied to Reciprocating Internal Combustion Engines

Abstract: Exergy analysis of the reciprocating internal combustion (IC) engines is studied by estimating various input and output energy transfer parameters concerning a dead state reference. Exergy terms such as fuel input, work output, cooling, and exhaust gas are measured and are set into the exergy balance equation to determine the amount of loss or destruction. Exergy destructions are found in many forms such as combustion (entropy generation), cylinder wall, friction, mixing, blow-by, and others. These exergy terms have been estimated by considering various factors such as engine type, fuel type, environmental condition, and others. In this article, the different methods employed in estimating these exergy terms have been reviewed. It attempts to make a compendium of these evaluation methods and segregates them under individual exergy terms with necessary descriptions. The fuel input measurement is mostly based on Gibb's free energy and the lower heating value, whereas its higher heating value is used during the fuel exergy calculation on a molar basis. The work output of the engines is estimated either from the crankshaft or by analyzing the cylinder pressure and volume. The exergy transfer with cooling medium and exhaust gas depends on the temperature of the gas. The maximum achievable engine performance is quantified by estimating the exergy efficiency. This piece of study will not only provide plenty of information on exergy evaluation methods of IC engines but will also allow future researchers to adopt the appropriate one.

Methanol/ Ethanol/ Butanol-Gasoline Blends Use in Transportation Engine-Part 1: Combustion, Emissions, and Performance Study

Abstract: Primary alcohols such as methanol, ethanol, and butanol have exhibited excellent potential as possible alternative fuels for spark ignition (SI) engines because they are renewable, cleaner and safer to store and transport. However, it remains important to investigate the technical feasibility of adapting these primary alcohols in existing SI engines. In this research, a multi-point port fuel injection (MPFI) system equipped SI engine was used for assessing and comparing the combustion, performance, and emission characteristics of various alcohol-gasoline blends (gasohols) vis-à-vis baseline gasoline. The experiments were performed for different engine loads at rated engine speed. Experimental results exhibited relatively superior combustion characteristics of the engine fueled with gasohol than the baseline gasoline, especially at medium engine loads. Among different test fuels, the methanol-gasoline blend (GM10) exhibited relatively more stable combustion characteristics than the ethanol-gasoline blend (GE10) and butanol-gasoline blend (GB10). In this study, relatively superior engine performance of the gasohol-fueled engine was observed at all engine loads and speeds. GB10 exhibited the highest brake thermal efficiency (BTE), followed by GM10 amongst all test fuels. The effect of improved combustion was also reflected in the emission characteristics, which exhibited that GB10 emitted relatively lower carbon monoxide (CO) and hydrocarbons (HC) than other test fuels. GB10 emitted relatively higher nitrogen oxides (NOx) than GM10 and GE10. Unregulated emission results exhibited that the engine fueled with gasohols emitted relatively lower sulfur dioxide (SO2), ammonia (NH3), and various saturated and unsaturated HCs than the baseline gasoline. The GM10-fuelled engine was relatively more effective in reducing unregulated emissions among all test fuels. This study concluded that methanol and butanol blending with gasoline resulted in superior engine performance and reduced harmful emissions in MPFI transport engines. This offered an excellent option to displace fossil fuels partially and reduce emissions simultaneously.

Validation of Gasoline Surrogates through Thermodynamic Analysis of Spark-Ignition Engine

Abstract: The investigation aims to evaluate the impacts of commercial gasoline and gasoline surrogates on energy and exergy efficiencies in a spark-ignition engine. In this investigation, a new approach for formulating next generation gasoline surrogates is investigated through testing these surrogates in a multi-cylinder SI engine. Energy and exergy analyses were carried out using the primary reference fuel-methylcyclohexane (PRF-MCH) blend (82.88% iso-octane + 9.16% n-heptane + 7.96% methylcyclohexane), primary reference fuel with 1,2,4-Trimethylbenzen (PRF-1,2,4-TMB) blends (76% iso-octane + 9% n-heptane + 15% 1,2,4-Trimethylbenzene and 61% iso-octane + 9% n-heptane+ 30% 1,2,4-trimethylbenzene) and commercially available gasoline (gasoline) in an SI engine. The engine investigation results show that the PRF-MCH blend is a promising surrogate to reproduce the gasoline fuel engine characteristics such as combustion and emission characteristics of gasoline fuel. The detailed experiments were executed at the SI-engine speed conditions of 1500 rpm and 2500 rpm. It is found that PRF-MCH blend energy-exergy efficiencies are comparable to commercially available gasoline. It can also be concluded that engine testing in terms of energy-exergy analyses for proposed gasoline surrogates provides a qualitative and quantitative understanding of combustion behavior, emission characteristics, assessment of the effectiveness, and useful work potential gasoline surrogates.