Study & Development Of Electronic Control EGR System For Engines With Ethanol-Diesel Blend Fuel

In order to meet the requirement of stringent emissions control legislation increasingly and improvement of fuel consumption and power of diesel, the advanced diesel engine solicits highly criteria for its overall performances. In recent years, diesel has undergone very significant improvements in terms of fuel economy and exhaust emissions. However, it is true that a major difficulty with the diesel engine is to control the emissions of nitrogen oxides (NOx) and particulate mater (PM). Recent research showed that ethanol-diesel blend fuel can effectively reduce the emissions of PM, but the reduction of NOx is not obvious, Exhaust Gas Recirculation (EGR) is one of the more promising strategies to reduce NOx emissions within the cylinder directly. So the combination of ethanol-diesel blend fuel and EGR could meet the requirement of more stringent diesel emission regulations.Based on the research project "the research and development of ethanol/diesel blend fuel vehicle engines " funded by Guangdong Province, this paper launched the study of EGR control technology on a diesel model DL190-12 manufactured by Shunde Deli Machinery Co.Ltd. The paper analyzed the advantages and disadvantages of various types of EGR control system, selected a suitable configuration program of EGR system, carried out whole design of EGR system. It was proposed a EGR calibrating method on engine line condition to get the best vacuum of EGR valve by engine load characteristic experiment. The study carried out calibration test for EGR rate of engine. In order to integrating optimum engine performance, the paper processed the data of engine calibration by value engineering principles. It was proposed the evaluation index, given their weights, and got the best vacuum MAP of EGR valve by two-grading evaluation methods. An EGR electronic control system was developed for DL190-12 engine with ethanol-diesel blend fuel, and the hardware and software for the system were designed. It detects engine's condition by sensors, then ECU send control signals to EGR solenoid according to it's processing results. And the lift of EGR valve is controlled by the solenoid in the EGR electronic control system. It realized the control of EGR rate covering entire engine condition range.The engine dynamometer tests showed that comparing with the original diesel engine DL190-12, the NOx emission can be reduced by 50~90%, PM reduced by 20%, HC,CO is close to original data at low speed and load condition, but increased by 20% at high speed and high load condition, fuel consumption is almost at low load condition, but there is a little increase in 10% at high speed and high load condition for the ethanol-diesel blend fuel engines equipped with the electronic control EGR system developed in the paper, The above results show that it has obtained the appropriate trade-of among the fuel economy, PM ,HC and CO emissions of the engine, and the reduction of NOx emissions is significant with the EGR control system developed in the study.