汽车车载油气回收技术的研究与发展

Research and development of onboard refueling vapor recovery techniques in cars

随着汽车保有量不断增大,汽车燃油蒸发排放问题愈发突出,相较于第2阶段加油站油气回收系统,车载油气回收(ORVR)系统效率更高,有利于汽车节能减排。为了明确车载油气回收技术亟需解决的关键技术难题、开发优化车载油气回收装置,该文分析了汽车车载油气回收技术的发展历程,介绍了典型的车载油气回收系统结构及工作原理;通过对加油管和炭罐的研究现状分析,指出加油管的设计是一个自液封的设计,合理的炭罐脱附机制能够减少炭罐的脱附对发动机空燃比的影响;通过对油气蒸发排放数学模型研究现状分析,明确汽车燃油蒸发排放影响因素并预测蒸发排放量;特别地,针对混合动力汽车发动机工作特性与传统汽油车发动机的不同,讨论了混合动力汽车的炭罐脱附控制策略。最后,总结并预测了汽车车载油气回收技术存在的问题及未来发展趋势,指出为减少汽车蒸发排放直至达到“零排放”的标准,车载油气回收技术需要走向自动化,提高精度控制。

With the increasing of vehicle population,the problem of evaporative emissions is becoming severer.Compared with stageⅡsystems,the onboard refueling vapor recovery(ORVR)systems have more efficiency,which is conducive to energy conservation and emission reduction.This paper reviewed the development history of onboard vapor recovery techniques to clarify the key technical problems that need to be solved urgently for developing and optimizing onboard refueling vapor recovery systems,and several typical onboard vapor recovery systems were introduced.The research status of filler pipe and carbon canister has been researched.The results indicate that the key point of filler pipe design is the liquid seal,and a reasonable control strategy of canister can reduce the influence of canister desorption on the air-fuel ratio of the engine.Also,the research status of the mathematical model of onboard vapor recovery system has been studied to understand the influencing factors and predict the evaporative emissions.In view of the difference between the operating characteristics of the hybrid electric vehicles engines and the gasoline vehicles engines,the control strategy of canister in hybrid electric vehicles has been discussed.Finally,the problems and future development trends of onboard vapor recovery techniques were summarized.The onboard vapor recovery systems need to be automated to achieve high-precision control to reduce evaporative emissions until the“zero emission”standard is met.