The influence of multi-speed transmissions on electric vehicles energy consumption

Abstract

The electric vehicle (EV) represents an important option in the process of road transport decarbonization. The limited driving range and high speed performances are obstacles for EV customer acceptance. While until now the emphasis for the improvement was on battery, power electronics and motor technologies, it becomes obvious that the transmission must be also addressed. The extensively used single-ratio transmission can satisfy the demands of city use, but do not attain other important functional needs that are ensured by conventional and hybrid electric vehicles. The aim of this paper is to analyse the energy consumption of an EV with multi-speed transmission in five test cycles among which Worldwide Harmonized Light duty Test Cycle (WLTC) is considered. This study is done by means of simulation using a model specifically developed in a simulation environment. In the interest of analysing the performances in several test cycles, one needs to compare global parameters such as: vehicle speed fluctuation (VSF), overall transmission efficiency, energy consumption ratio (ECR). A comparison between test cycles is made taking into consideration a relative parameter (ECR). The correlation between ECR and VSF is investigated as well. The results are also compared with those produced for a vehicle with diesel engine.

Determination of the number of speeds of a mechatronic transmission of a road car based on a typical specified driving mode

“…During designing mechatronic transmissions of trucks intended for operation on the roads of the territory of the Russian Federation, characterized by a long length and high permissible speeds, the task of improving the energy efficiency of the mechatronic transmission and determining the required number of gears becomes one of the most important [2,3]. The lack of consensus among leading manufacturers and the use of their production experience does not allow us to reliably determine the required number of gears for mechatronic transmissions.…”

"DETERMINATION OF RATIONAL NUMBER OF GEARS OF MECHATRONIC TRANSMISSION BY COMPUTATIONAL EVALUATION OF VEHICLE LOADING BY DRIVING CYCLES"

“…При проектировании мехатронных трансмиссий грузовых автомобилей, предназначенных для эксплуатации на дорогах территории РФ, характеризующихся большой протяженностью и высокими допустимыми скоростями движения, задача повышения энергоэффективности мехатронной трансмиссии и определения требуемого количества передач становится одной из важнейших [2,3]. Отсутствие единого мнения среди ведущих производителей и использование их опыта производства не позволяет гарантированно определить требуемое количество передач для мехатронных трансмиссий.…”