Lean operation of spark ignition (SI) automotive engines offers attractive performance incentives. Lowered combustion temperatures inhibit NO, pollutant formation while reduced manifold throttling minimizes pumping losses, leading to higher efficiency. These benefits are offset by the reduced combustion speed of lean mixtures, which can lead to high cycle-to-cycle variation and unacceptable eng...

The concept of minimum ignition energy (MIE) has traditionally formed the basis for studying ignition hazards of fuels. However, the viewpoint of ignition as a statistical phenomenon appears to be more consistent with the inherent variability in engineering test data. We have developed a very low-energy capacitive spark ignition system to produce short sparks with fixed lengths of 1 to 2 mm, an...

The normal specifications of motor gasolines as well as their combustion characteristics in internal combustion engines are reviewed in this paper. The effective factors influencing the fuel performance, such as the molecular structure of the fuel constituents, the operating conditions and the atmospheric pressure and temperature are also discussed. A relationship between the optimum octane num...

A three-dimensional Reynolds-Averaged Navier-Stokes (RANS) simulation was carried out on an unscavanged auto-ignition prechamber-cylinder configuration in order to understand better the ignition conditions inside the engine. The sensitivity to different boundary conditions like initial gas and wall temperature was tested and flow simulations coupled with a 55 species chemical mechanism were car...

Di methyl carbonate (DMC) has a lot of good properties to be used as a blend with gasoline. In order to improve the efficiency, combustion stability and emission performance of a spark ignition engine, oxygenated fuel (DMC) is added to a gasoline. In this experimental work, the effect of using 100% gasoline and gasoline-DMC blends (D5, D10, D15 and D20) on four cylinder engine performance and e...

Abbreviations: aBDC, after bottomdead center; aTDC, aft bottomdead center; bTDC, before top dead center; CA50, cra fraction reaches to 50%; CI, compression ignition; COVime indicated mean effective pressure; DI, direct injection; DIS DOI, duration of injection (first DOI1, second DOI2); EGR, homogenous charge compression ignition; IMEP, indicat injection ratio; MPRR, maximum pressure rise rate;...

We report on the design and output performances of a diode pumped, high-peak power Nd:YAG/Cr 4+ :YAG laser with four-beam output. The system posses the ability to chose independently the focus of each laser beam, being seen as a solution for a laser spark with multiple-point ignition. The laser ignition of a gasoline direct injected engine has several advantages in comparison with ignition by e...

Homogeneous-charge compression ignition (HCCI) engines have been shown to have higher thermal efficiencies and lower NOx and soot emissions than spark ignition engines. However, HCCI engines experience very large heat release rates which can cause too rapid an increase in pressure. One method of reducing the maximum heat release rate is to introduce thermal inhomogeneities, thereby spreading th...

Laser ignition (LI) has been shown to offer many potential benefits compared to spark ignition (SI) for improving the performance of internal combustion (IC) engines. This paper outlines progress made in recent research on laser ignited IC engines, discusses the potential advantages and control opportunities and considers the challenges faced and prospects for its future implementation. An expe...