Petroleum based fuel consumption and greenhouse gas emissions have been reduced using hybrid applications in the automotive sector in the last decades. Parallel hybrid construction, which is equipped with internal combustion engine and electric motor, for the propulsion of vehicle is one of the most preferred alternatives for hybridization. The purpose of this study is to investigate the changes in the fuel consumption and exhaust emissions in the powertrain components for a parallel hybrid with torque coupling unit for different values of gear ratios. Investigation of the effects of gear ratios on the torque coupling unit, gearbox unit, and differential is performed by simulating the parallel hybrid powertrain in the MATLAB^® and Simulink^® environment. New European Drive Cycle speed and acceleration requirements are defined as the input parameters for this simulation. The fuel consumption, exhaust emission, and state of charge of the battery are determined according to the power requirement of internal combustion engine and electric motor. Five different gear ratio combinations are simulated. These combinations are arranged by using alternative ratios in the third stage of gearbox unit, torque coupling unit, and differential. The best gear ratio distribution among these combinations are determined for reducing the fuel consumption and the carbon dioxide (CO₂), carbon monoxide (CO), nitrogen oxides (NO_x), and hydrocarbon (HC) emissions. It is found that an improvement of 17% in the fuel consumption and reductions of 9.1% in the CO₂, 18% in the CO, 4% in the HC, and 8% in the NO_x emissions can be achieved by the proper arrangements of gear ratios in the powertrain components.

在过去的几十年中，使用混合动力技术在汽车领域减少了基于石油的燃料消耗和温室气体排放。配备有内燃发动机和电动机的，用于推进车辆的并联混合动力结构是混合动力的最优选替代方案之一。这项研究的目的是研究具有不同齿数比的带有扭矩耦合单元的并联混合动力系统的动力总成部件中燃油消耗和废气排放的变化。对扭矩传动比的耦合单元，变速箱单元，和差的影响调查是通过在MATLAB模拟并联混合动力系统进行^®和Simulink ^®环境。新的欧洲行驶周期速度和加速度要求定义为此模拟的输入参数。电池的燃料消耗，废气排放和充电状态取决于内燃机和电动机的功率要求。模拟了五种不同的齿轮比组合。这些组合是通过在变速箱单元，扭矩耦合器单元和差速器的第三级中使用替代传动比来安排的。确定这些组合中的最佳齿轮比分布以减少燃料消耗和二氧化碳（CO ₂），一氧化碳（CO），氮氧化物（NO _x）和碳氢化合物（HC）排放。研究发现，17％的燃料消耗和9.1％的减少中的CO的改进₂，在CO 18％，在HC 4％，并且在NO 8％_X的排放量可以通过适当的安排来实现动力总成组件中的齿轮比。