Yintong Liu

In-cycle combustion feedback control for abnormal combustion based on digital ion current signal:

For better stability of ion current employed for in-cycle combustion diagnosis and feedback control, this research develops a digital post-processing unit for in-cylinder ion current signals. Based on the processed digital ion current signal, abnormal combustion in gasoline direct injection engine is successfully detected, and the in-cycle remedy feedback control is achieved as well. Both re-ignition and re-injection are utilized for misfiring remedy, and only re-injection is employed for knocking inhibition. The accuracy of misfiring diagnosis is achieved no less than 94%, and the re-injection combined with re-ignition operation is shown to be feasible for misfiring remedy as well. The accuracy of knocking diagnosis is around 85% (knocking rate = 20%). The re-injection under the pre-knocking condition is shown to be effective for knocking inhibition.

An Ultra-High Power Ignition System for EGR-Diluted GDI Engine

An innovative ignition system was evaluated for its suitability for EGR-diluted GDI engine. The energy measurements showed the ultra-high power ignition system could provide about 12 kW power and generated a strong shock wave captured by a high-speed photography. The 2000 r/min@0.44 MPa BMEP engine test showed a 10% EGR ratio limit extension and the enhanced flame kernel and flame propagation helped to raise the thermal efficiency by 5.5% relatively.

Development and Application of Dual UniValve System Based on a GDI Engine with SI/HCCI Dual Combustion Modes

A full-variable-valvetrain prototype named Dual UniValve System has been developed for a GDI engine with SI/HCCI dual combustion modes, improving the fuel economy and emission performance under some of part and low load conditions. Based on the dynamic performance test, reliability of Dual UniValve System has been qualified. In addition, under the NEDC condition, UniValve system can optimize the friction loss significantly. The switching response time between valvelifts of 0–8 mm is only 0.16 s, which provides a fast response for transient conditions. Furthermore, in the engine test with Dual UniValve System, SI/HCCI combustion mode switching has been also achieved with a fast speed, which increased indicated efficiency by 10 % and reduced NOX emissions by 99 %.