Modelling and Analyzing Electric Vehicles with Geared Transmission Systems: Enhancement of Energy Consumption and Performance (original) (raw)
Related papers
International Journal of Engineering Research and Technology (IJERT), 2013
https://www.ijert.org/modelling-and-analyzing-electric-vehicles-with-geared-transmission-systems-enhancement-of-energy-consumption-and-performance https://www.ijert.org/research/modelling-and-analyzing-electric-vehicles-with-geared-transmission-systems-enhancement-of-energy-consumption-and-performance-IJERTV2IS110249.pdf The main aim of this paper is to study the potential impacts in performance and energy consumption by utilising a geared transmission in electric vehicle driveline. This is achieved by modelling and analysing the powertrain of a generic electric vehicle using Matlab/Simulink-QSS Toolkit, with and without a transmission system of varying levels of complexity, to investigate whether the addition of a gearbox results in significant values of predicted efficiency gains. Predicted results are compared for a typical electrical vehicle (EV) in three cases: without a gearbox, with a continuously variable transmission (CVT), and with a conventional stepped gearbox. Predictions are made over the standard driving cycles. One of the critical features in this paper is the usage of the electric motor in its region of high efficiency. Consequently, two motors are modeled in this work in order to understand the sensitivity of the results to the assumptions about motor efficiency maps. These motors will be referred to as a theoretical motor derived from generic equations and a practical motor which is effectively a look-up map from the manufacturers’ data. The results showed that it is possible to improve overall performance and energy consumption levels using a continuously variable ratio gearbox.
Model-Based Estimation of Transmission Gear Ratio for Driving Energy Consumption of an EV
Electronics, 2021
This paper presents a numerical study of the effect of the transmission configuration on the energy consumption of an electric vehicle. The first part of this study is related to a vehicle simulation model that takes into consideration vehicle resistances such as aerodynamic, rolling and inertial resistance as well as the traction force. The model was then validated by means of vehicle acceleration time, from 0 to 100 km/h in the case of a single-speed gearbox. Vehicle power demand and electrical energy consumption were then evaluated over three standardized test cycles: WLTC-Class 3, NEDC and FTP-75. For each cycle, two cases were studied: a single-speed and dual-speed gearbox. Very different power demand was observed between the cycles in terms of maximum and average driving power. The most power-demanding cycle was WLTC, while NEDC was less power demanding. However, the specific driving energy per kilometer was very similar for NEDC and FTP-75, as it respectively accounted to 0.1...
Energy use efficiency of electric automobile depending on transmission gear ratio
2018
When converting an internal combustion vehicle to electric power, it is important to choose the right transmission gear ratio to ensure optimum performance of the vehicle. A converted automobile is usually equipped with a standard transmission gearbox, while the motor control block is programmed for one particular gear. During the operation of an electric automobile, the gears could be shifted, when the automobile is stopped, as the clutch is not used by the electric automobile. In choosing a gear ratio, a priority could be to ensure good dynamic performance or high speed achievement. However, one of the most important parameters is energy consumption and the distance covered per charge. After identifying the optimum gear ratio or the gear to be used, the unused gears of the transmission gearbox of the converted vehicle could be dismantled, thereby reducing the weight of the vehicle and increasing the transmission gear ratio. A converted Renault Clio with a 96 V battery system and a standard 5-speed transmission gearbox was road tested. The experimental dataspeed, change in voltage and current, battery temperature and measurement time were recorded by a multichannel data logger. The road tests were carried out at constant speeds-50 and 90 km•h-1. The road tests showed that energy consumption by the electric automobile in the fourth gear at 50 km•h-1 was the lowest, consuming a power of 5.86 kW, while in the fourth gear at 90 km•h-1 it consumed 15.43 kW.
Transmission configuration effect on total efficiency of Electric Vehicle powertrain
2014
This study investigates the impact of transmission topology on the combined mechanical and electrical efficiency of an Electric Vehicle (EV) by comparing two types of transmissions. In an EV, due to space restrictions, a relatively high-speed electric motor is used with a reduction gear to provide adequate torque production. Since the electric motor's efficiency varies according to the amount of applied torque at different speeds, there is a question of whether a multi-step gearbox capable of increasing the electric efficiency by shifting operation points along constant power curves can also improve the powertrain overall efficiency. A mathematical model is developed for calculating the power losses due to movement of mechanical components. In this study, a geartrain is taken into closer analysis where a single reduction gear and a five-step gearbox are compared from an efficiency point of view.
Experimental Research of Transmissions on Electric Vehicles' Energy Consumption
The growth of electric vehicles share of total passenger-vehicle sales is evident and is expected to be a very big market segment by 2030. Range of travel and pricing are the most influencing factors that affect their gain in market share. As so, powertrain development is a key technology factor researched by the automotive industry. To explore, among others, how the energy consumption of zero emission vehicles is affected by different transmissions, we developed, built and installed a variety of them on a custom hydrogen fuel cell powered urban vehicle. In this work we present a comparison of the effect, on the energy consumption of the proposed testbed, of a prototype custom build 2-speed gearbox and a single stage transmission. Results presented show a reduction of the overall energy consumption with the use of the 2-speed gearbox, compared to single stage, as well as the effect of gear change speed, related to speed, in energy consumption. Finally, a correlation of experimental results using a custom build CVT is conducted compared to single stage transmission. A comparison to simulation results found in literature is performed for all the transmissions tested on road.
Evaluation of a 2-speed transmission on electric vehicle's energy consumption
2014
In order to explore the impact of transmission use on the energy/fuel consumption of zero emission vehicles, a 2speed gearbox was developed and tested. The gearbox is installed on a hydrogen fuel cell powered urban vehicle, the ER14, a prototype designed by the TUC Eco Racing team at the Technical University of Crete. In this work the ER14 is used as a testbed vehicle so as to measure and evaluate fuel consumption with and without gear changing. Actual road tests were conducted and experimental results are presented, showing reduction of electric vehicle energy consumption with the use of the gearbox.
Sustainability, 2020
The electric vehicle (EV) market has grown over the last few years and even though electric vehicles do not currently possess a high market segment, it is projected that they will do so by 2030. Currently, the electric vehicle industry is looking to resolve the issue of vehicle range, using higher battery capacities and fast charging. Energy consumption is a key issue which heavily effects charging frequency and infrastructure and, therefore, the widespread use of EVs. Although several factors that influence energy consumption of EVs have been identified, a key technology that can make electric vehicles more energy efficient is drivetrain design and development. Based on electric motors’ high torque capabilities, single-speed transmissions are preferred on many light and urban vehicles. In the context of this paper, a prototype electric vehicle is used as a test bed to evaluate energy consumption related to different gear ratio usage on single-speed transmission. For this purpose, r...
Advances in Automobile Engineering, 2013
The main aim of this paper is to study the potential impacts in hybrid and full electrical vehicles performance by utilising continuously variable transmissions. This is achieved by two stages. First, for Electrical Vehicles (EVs), modelling and analysing the powertrain of a generic electric vehicle is developed using Matlab/Simulink-QSS Toolkit, with and without a transmission system of varying levels of complexity. Predicted results are compared for a typical electrical vehicle in three cases: without a gearbox, with a Continuously Variable Transmission (CVT), and with a conventional stepped gearbox. Second, for Hybrid Electrical Vehicles (HEVs), a twin epicyclic power split transmission model is used. Computer programmes for the analysis of epicyclic transmission based on a matrix method are developed and used. Two vehicle models are built-up; namely: traditional ICE vehicle, and HEV with a twin epicyclic gearbox. Predictions for both stages are made over the New European Driving Cycle (NEDC).The simulations show that the twin epicyclic offers substantial improvements of reduction in energy consumption in HEVs. The results also show that it is possible to improve overall performance and energy consumption levels using a continuously variable ratio gearbox in EVs.
Increase of the energy efficiency of passenger cars using different types of transmissions
2010
One of the main parameters to increase the energy efficiency is to reduce fuel consumption. For this purpose a number of vehicles fuel economy standards (FE) are introduced. They are being implemented all over the world in order to conserve energy and for reduction in carbon dioxide emissions. In this paper, it has been discussed how different types of transmission technology could contribute on fuel economy and energy efficiency of passenger cars. Different types of transmission (automatic transmission, manual gear transmission or continuously variable transmission-CVT) differently influence fuel consumption. For examples, the CVT offers high fuel economy, presumably because it ensures a low brake specific fuel consumption (BSFC) driving condition with its continuously variable ratio characteristics. Also, it is shown that automatic transmissions are almost always less energy efficient than manual transmissions due mainly to viscous and pumping losses. The practical use of the increase of the energy efficiency of passenger cars using different types of transmissions is based on the comparison reviews investigating fuel consumption and acceleration characteristics of passenger cars with different type transmission concepts which show the significant advantages offered by new transmission concepts currently being launched as volume production models.
On the Energy Efficiency of Dual Clutch Transmissions and Automated Manual Transmissions
Energies
The main benefits of dual clutch transmissions (DCTs) are: (i) a higher energy efficiency than automatic transmission systems with torque converters; and (ii) the capability to fill the torque gap during gear shifts to allow seamless longitudinal acceleration profiles. Therefore, DCTs are viable alternatives to automated manual transmissions (AMTs). For vehicles equipped with engines that can generate considerable torque, large clutch-slip energy losses occur during power-on gear shifts and, as a result, DCTs need wet clutches for effective heat dissipation. This requirement substantially reduces DCT efficiency because of the churning and ancillary power dissipations associated with the wet clutch pack. To the knowledge of the authors, this study is the first to analyse the detailed power loss contributions of a DCT with wet clutches, and their relative significance along a set of driving cycles. Based on these results, a novel hybridised AMT (HAMT) with a single dry clutch and an electric motor is proposed for the same vehicle. The HAMT architecture combines the high mechanical efficiency typical of AMTs with a single dry clutch, with the torque-fill capability and operational flexibility allowed by the electric motor. The measured efficiency maps of a case study DCT and HAMT are compared. This is then complemented by the analysis of the respective fuel consumption along the driving cycles, which is simulated with an experimentally validated vehicle model. In its internal combustion engine mode, the HAMT reduces fuel consumption by >9% with respect to the DCT.