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Low heat rejection (LHR) combustion has been recognized as a potential technology for further fuel economy improvement. This paper aims to simulate how the piston top’s thermal barrier coating affects the engine’s thermal efficiency and emissions. Accordingly, a Thin-wall heat transfer model in AVL Fire software was employed. The effects of increasing the piston top surface temperature, comparing different thermal barrier coating material, were simulated at the engine’s rated power operating point, so as the piston top’s surface roughness. In comparison to a standard diesel engine, the indicated thermal efficiency (ITE) could increase by 0.4% when the surface temperature of the piston top changed from 575K to 775K.

Ultra-lean combustion of GDI engine could achieve higher thermal efficiency and lower NOx emissions, but it also faces challenges such as ignition difficulties and low-speed flame propagation. In this paper, the sparked-spray is proposed as a novel ignition method, which employs the spark to ignite the fuel spray by the cooperative timing control of in-cylinder fuel injection and spark ignition and form a jet flame. Then the jet flame fronts propagate in the ultra-lean premixed mixture in the cylinder. This combustion mode is named Sparked-Spray Induced Combustion (SSIC) in this paper. Based on a 3-cylinder 1.0L GDI engine, a 3D simulation model is established in the CONVERGE to study the effects of ignition strategy, compression ratio, and injection timing on SSIC with a global equivalence ratio of 0.50. The results show it is easier to form the jet flame when sparking at the spray front because the fuel has better atomization and lower turbulent kinetic energy at the spray front.

REEV (Range-Extended Electric Vehicle) can avoid the mileage anxiety of BEV (Battery Electric Vehicle). Nevertheless, RE (Range Extender) for passenger cars prefers to use ICE (Internal Combustion Engine) with smaller displacement and lower cylinder number, which is usually with a worse vibration performance at low speeds. As RE only outputs electricity, it provides the possibility to optimize NVH (Noise, Vibration, and Harshness) of the engine by PMSM (Permanent Magnet Synchronous Motor). By real-time control, the electromagnetic torque of PMSM can track the shaft torque fluctuation during engine strokes, especially the combustion stroke. When the instability and rolling torque of RE could be suppressed, NVH performance of RE can be improved. This paper presents simulation research on speed fluctuation suppression for RE engine based on dynamic torque compensation by controlling a PMSM.