Fundamental phenomena affecting low temperature combustion and HCCI engines, high load limits and strategies for extending these limits

Fuel design and management for the control of advanced compression-ignition combustion modes

Evolution, challenges and path forward for low temperature combustion engines

Combustion advancements in gasoline engines

Dual-Fuel PCI Combustion Controlled by In-Cylinder Stratification of Ignitability

The effect of injection timing and intake valve close timing on performance and emissions of diesel PCCI engine with a full engine cycle CFD simulation

Controlled Auto-Ignition (CAI) combustion, also known as HCCI or PCCI, has recently emerged as a viable alternative combustion process to the conventional spark ignition (SI) or compression ignition (CI) process for internal combustion (IC) engines, owing to its potential for high efficiency and extremely low emissions. One of the most effective and practical means of achieving CAI combustion in an engine is to retain or recycle the burnt gases. In order to understand better the effects of recycled burnt gases on CAI combustion, detailed analytical and experimental studies have been carried out. The analytical studies were performed using an engine simulation model with detailed chemical kinetics. The five effects of the recycled burned gases studied include: (1.)Charge heating effect: higher intake charge temperature due to hot burned gases; (2.)Dilution effect: the reduction of oxygen due to the presence of the burned gases; (3.)Heat capacity effect: due to higher specific heat capacity of burned gases; (4.)Chemical effect: chemical reactions involving CO2 and H2O in the burned gases (5.)Stratification effect: recycled burned gases are stratified from the fuel/air mixture. And the main conclusions are: (1.)The charge heating effect is mainly responsible for the advanced AI timing due to hot burned gases. It increases the heat release rate and shortens the combustion duration. (2.)The dilution effect does not affect AI timing, but it extends combustion duration. Its slows down the heat release rate only when large amount of burned gases is present. (3.)The heat capacity effect is mainly responsible for the reduction in the heat release rate, and it has a similar effect to extend the combustion duration as the dilution effect. (4.)The chemical effect does not affect AI timing and heat release rate. It reduces the combustion duration slightly at high concentrations of burned gases. (5.)The stratified burned gases facilitate the CAI combustion due to the presence of higher temperature region at the boundary between of the hot burned gases and combustible charge. Copyright © 2001 Society of Automotive Engineers, Inc.

Understanding the Effects of Recycled Burnt Gases on the Controlled Autoignition (CAI) Combustion in Four-Stroke Gasoline Engines

Cooled solar PV panels for output energy efficiency optimisation

Analysis the effect of advanced injection strategies on engine performance and pollutant emissions in a heavy duty DI-diesel engine by CFD modeling

Controlled autoignition (CAI) combustion has recently emerged as a viable alternative combustion process to the conventional spark ignition or compression ignition process for internal combustion engines, owing to its potential for high efficiency and extremely low NOx and particulate emissions. Since CAI combustion is a process dominated by chemical kinetics of the fuel-air mixture, an engine simulation model with detailed chemical kinetics has been developed and applied to a four-stroke gasoline engine fuelled with isooctane. After calibration and validation, the engine simulation model was used to study the effects of the intake temperature, exhaust gas recirculation (EGR), the air-fuel ratio, the compression ratio and the engine speed on CAI combustion in a four-stroke gasoline engine. The characteristics of CAI combustion investigated include the autoignition timing, the partial burning and knocking combustion and NO emission. Results show that CAI combustion could be achieved within a limited speed and load range. The lower end of the CAI combustion range was affected by partial burning, and the higher end of its operation was limited by knocking combustion. Among the engine parameters investigated, the intake charge temperature and EGR had the greatest effect on the CAI combustion process. The effect of EGR was further analysed in terms of its thermal (increase in heat capacity), dilution, chemical and charge heating effects by means of a series of simulation studies. It was found that the charge heating effect caused advanced ignition timing, faster heat release rate and moderate reduction in the CAI combustion duration. The thermal effect (increased heat capacity) retarded ignition, extended combustion duration and slowed down heat release rate. The dilution effect also resulted in longer combustion duration and slower burning but it did not affect the ignition timing. The chemical effect was found to accelerate the combustion process when the percentage of EGR was large.

Understanding of controlled autoignition combustion in a four-stroke gasoline engine

Zhijun Peng

Papers

The effect of injection timing and intake valve close timing on performance and emissions of diesel PCCI engine with a full engine cycle CFD simulation

Understanding the Effects of Recycled Burnt Gases on the Controlled Autoignition (CAI) Combustion in Four-Stroke Gasoline Engines

Cooled solar PV panels for output energy efficiency optimisation

Analysis the effect of advanced injection strategies on engine performance and pollutant emissions in a heavy duty DI-diesel engine by CFD modeling

Understanding of controlled autoignition combustion in a four-stroke gasoline engine