The paper proposes a novel pneumatic-fuel hybrid system,which combines a traditional internal combustion engine(ICE)and a pneumatic engine.One important merit of this concept is that the system can recover waste from cooling water of internal combustion engine to optimize the working process of pneumatic engine,and thus to improve the entire efficiency of the hybrid system.Meanwhile,energy-saving effect due to lower cooling fan power can be achieved on ICE by waste heat recovery of pneumatic engine.Based on thermodynamic analysis,an experimental system is designed and established for verification.The experimental results show that the performance of pneumatic engine is improved when the waste heat recovery concept of the hybrid system is applied.Then an application example on a 4-cylinder engine is analyzed and discussed using numerical simulation.The results show that the fan power of the ICE cooling system can be saved up to 50%by applying the hybrid system.Considering the appreciable improvements on the energy efficiency with only limited system modifications when the concept is applied to traditional ICE based power systems,the proposed hybrid concept has the potential to serve as an alternative technology aiming for energy saving and emission reduction.
建立了电液驱动气门柴油机仿真模型,利用试验获得的电液气门运动规律,分析气门重叠角、进气迟后角和排气提前角对柴油机动力性的影响,并对三者进行多参数优化,最后研究了排气迟后角对柴油机内部废气再循环(exhaust gas recirulation,EGR)率的影响。研究结果表明:应用电液驱动气门可使柴油机在中低转速时动力性和经济性有明显改善;受电液气门响应限制,随着转速升高,改善效果逐渐减弱;以1 500r/min为例,相对于排气门延迟关闭,排气门提前关闭对柴油机功率影响较大,且排气迟后角调整幅度较小时能获得较大内部EGR率。
