FIRCRI-a flexible injection rate common rail injector was developed. This paper presents the working principle and the configuration of the injector. As key technologies in development of the injector, a new fast response solenoid valve was developed and 4 dimensionless design parameters of hydraulic system were presented by through computer simulation and experimental study. The solenoid valve was deliberately designed so as to eliminate the hydraulic force acting on the valve. Other configuration parameters were also optimized so that the response time of the solenoid valve is 0.3ms. It is interesting to find that the response time of the injector is not only determined by the solenoid valve, but all parameters of the hydraulic system of the injector. The injector can realize pilot injection, which is less than 2.5mm3, at a controllable phase and multi-injections. The injection rate of the injector can be regulated as echelon and boot shape, according to the requirement fitting engine combustion system by change some parts of the injector.

The paper has presented a new reduced chemical kinetic model for the Homogeneous Charge Compression Ignition (HCCI) combustion of n-heptane in an engine, which contains 44 species and 72 reactions. The reduced model includes four sub-models: the first is the low-temperature reaction sub-model, which is established by determining particular aldehydes and small hydrocarbons in the Li-model developed by Li et al. The second is the sub-model for large molecules decomposing directly into small molecules that is developed for linking the low-temperature reaction with high-temperature reaction. The third one is used for high-temperature reaction, which is generated by several modifications to Griffiths-model developed by Griffiths et al., omitting several reactions, adding two oxidization reactions related to CO and CH3O. In addition, the sub-model for NOx formation from the reduced kinetic model presented by Golovitchev is also combined into the reduced model. This reduced model has been used to simulate the cool-flame and hot-flame combustion process of n-heptane as well as NOx formation in HCCI engines, and the calculation results agree well with those of the detailed model proposed by Curran et al. The CPU time of consuming in the reduced model is 1/1,000 that of the detailed model. Thus, the HCCI engine simulations using chemistry with CFD are attainable by using the reduced model.

FIRCRI-a flexible injection rate common rail injector was developed. This paper presents the working principle and the configuration of the injector. As key technologies in development of the injector, a new fast response solenoid valve was developed and 4 dimensionless design parameters of hydraulic system were presented by through computer simulation and experimental study. The solenoid valve was deliberately designed so as to eliminate the hydraulic force acting on the valve. Other configuration parameters were also optimized so that the response time of the solenoid valve is 0.3ms. It is interesting to find that the response time of the injector is not only determined by the solenoid valve, but all parameters of the hydraulic system of the injector. The injector can realize pilot injection, which is less than 2.5mm3, at a controllable phase and multi-injections. The injection rate of the injector can be regulated as echelon and boot shape, according to the requirement fitting engine combustion system by change some parts of the injector.

作者提出了基于多脉冲喷射和BUMP燃烧室的MULINBUMP-HCCI复合燃烧技术。发动机实验和CFD数值模拟研究表明，多脉冲喷射参数，特别是多脉冲喷射定时可以控制预混合气的形成，从而控制燃烧放热率。具有分布式放热率的工作过程的热效率与直喷式柴油机相当。但同时改善了NOx和碳烟排放，在不采用废气再循环的条件下，NOx排放在较低负荷时只有11×10-6，高负荷时也不超过250×10-6。碳烟排放始终小于0.5BSU。

A sequential port injection, lean-burn, fully electronically-controlled compressed natural gas (CNG)/Diesel dual-fuel engine has been developed based on a turbo-charged and inter-cooled direct injection (D.I.) diesel engine. During the optimization of engine overall performance, the effects of pilot diesel and pre-mixed CNG/air mixture equivalence ratio on emissions (CO, HC, NOx, soot), knocking, misfire and fuel economy are studied. The rich and lean boundaries of the pre-mixed CNG/air mixture versus engine load are also provided, considering the acceptable values of NOx and THC emissions, respectively. It is interesting to find that there is a critical amount of pilot diesel for each load and speed point, which proved to be the optimum amount of pilot fuel. Any decrease in the amount of pilot diesel from this optimum amount results in an increase of NOx emissions, because the pre-mixed CNG/air mixture must be made richer, otherwise THC emissions would increase. However, the soot emissions remain almost unchanged at a very low level.