Performance of homogeneous charge compression ignition (HCCI) engine with common rail fuel injection

A homogeneous charge compression ignition (HCCI) engine system fuelled with dimethyl ether (DME) and methanol-reformed gas (MRG), both produced from methanol by onboard reformers using exhaust heat, has been proposed in previous research. Adjusting the proportions of DME and MRG with different ignition properties effectively controlled the ignition timing and load in HCCI combustion. The use of the single liquid fuel, methanol, also eliminates the inconvenience of carrying two fuels while maintaining the effective ignition control effect. Because reactions producing DME and MRG from methanol are endothermic, a part of the exhaust gas heat energy can be recovered during the fuel reforming. Methanol can be reformed into various compositions of hydrogen, carbon monoxide, and carbon dioxide. The present paper aims to establish the optimum MRG composition for the system in terms of ignition control and overall efficiency. The results show that an increased hydrogen fraction in MRG retards the onset of high-temperature oxidation and permits operation with higher equivalence ratios. However, the MRG composition affects the engine efficiency only a little, and the MRG produced by the thermal decomposition having the best waste-heat recovery capacity brings the highest overall thermal efficiency in the HCCI engine system fuelled with DME and MRG.

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Modeling and Model-based Control of Homogeneous Charge Compression Ignition (HCCI) Engine Dynamics

Automotive Model Predictive Control - Lecture Notes in Control and Information Sciences ◽

10.1007/978-1-84996-071-7_6 ◽

2010 ◽

pp. 89-104 ◽

Cited By ~ 2

Author(s):

Rolf Johansson ◽

Per Tunestål ◽

Anders Widd

Keyword(s):

Homogeneous Charge Compression Ignition ◽

Compression Ignition ◽

Model Based Control ◽

Hcci Engine ◽

Model Based ◽

Homogeneous Charge

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Experimental and Numerical Analysis on the Influences of Direct Fuel Injection into Oxygen-Depleted Environment of a Homogeneous Charge Compression Ignition Engine

Journal of Energy Resources Technology ◽

10.1115/1.4050051 ◽

2021 ◽

pp. 1-29

Author(s):

Ratnak Sok ◽

Kei Yoshimura ◽

Kenjiro Nakama ◽

Jin Kusaka

Keyword(s):

Homogeneous Charge Compression Ignition ◽

Fuel Injection ◽

Double Pulse ◽

Gasoline Direct Injection ◽

Oh Radicals ◽

Compression Ignition ◽

Compression Ignition Engine ◽

Intake Stroke ◽

Direct Fuel Injection ◽

Homogeneous Charge

Abstract The oxygen-depleted environment in the recompression stroke can convert gasoline fuel into light hydrocarbons due to thermal cracking, partial oxidation, and water-gas shift reactions. These reformate species can influence the combustion characteristics of gasoline direct injection homogeneous charge compression ignition (GDI-HCCI) engines. In this work, the combustion phenomena are investigated using a single-cylinder research engine under a medium load. The main combustion phases are experimentally advanced by direct fuel injection into the negative valve overlap (NVO) compared with that of intake stroke under single/double pulse injections. NVO peak in-cylinder pressures are lower than that of motoring due to the limited O2 concentration, emphasizing that endothermic reactions occur during the overlap. This phenomenon limits the oxidation reactions, and the thermal effect is not pronounced. The 0-D chemical kinetics results present the same increasing tendencies of classical reformed species of rich-mixture such as C3H6, C2H4, CH4, CO, and H2 as functions of injection timings. Predicted ignition delays are shortened due to the additions of these reformed species. The influences of the reformates on the main combustion are confirmed by 3-D CFD calculations, and the results show that OH radicals are advanced under NVO injections relative to intake stroke injections. Consequently, earlier heat release and cylinder pressure are noticeable. Parametric studies on the effects of injection pressure, double-pulse injection, and equivalence ratio on the combustion and emissions are also discussed experimentally.

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