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Power Transmission, Brakes and Cooling Systems
Published in Iqbal Husain, Electric and Hybrid Vehicles, 2021
The three primary types of transmission are: manual, automatic and continuously variable transmissions (CVTs). With the manual transmission, the driver shifts the gears manually in relation to the vehicle speed using the clutch pedal for engagement and disengagement. The driver skill plays a big role with manual transmissions for maximizing the performance of the vehicle. In automatic transmissions, the gear shifting is accomplished through the vehicle controllers without any intervention of the driver. These transmissions also allow the engine to idle when the vehicle is stopped. The CVT also does not require any driver intervention, but provides an infinite number of gear ratios rather than a fixed set. A general overview of the three transmissions is given in the following.
Fundamentals of Vehicle Propulsion and Braking
Published in Mehrdad Ehsani, Yimin Gao, Stefano Longo, Kambiz M. Ebrahimi, Modern Electric, Hybrid Electric, and Fuel Cell Vehicles, 2018
Mehrdad Ehsani, Yimin Gao, Stefano Longo, Kambiz M. Ebrahimi
An automotive power train, as shown in Figure 2.10, consists of a power plant (engine or electric motor), a clutch in a manual transmission or a torque converter in an automatic transmission, a gearbox (transmission), final drive, differential, drive shaft, and drive wheels. The torque and rotating speed from the output shaft of the power plant are transmitted to the drive wheels through the clutch or torque converter, gearbox, final drive, differential, and drive shaft. The clutch is used in a manual transmission to couple or decouple the gearbox to the power plant. The torque converter in an automatic transmission is a hydrodynamic device functioning as the clutch in a manual transmission with a continuously variable gear ratio (for more details, see Section 2.6). The gearbox supplies a few gear ratios from its input shaft to its output shaft for the power plant torque–speed profile to match the requirements of the load. The final drive is usually a pair of gears that supply a further speed reduction and distribute the torque to each wheel through the differential.
Fundamentals of Vehicle Propulsion and Brake
Published in Mehrdad Ehsani, Yimin Gao, Ali Emadi, and Fuel Cell Vehicles, 2017
Mehrdad Ehsani, Yimin Gao, Ali Emadi
An automotive power train, as shown in Figure 2.10, consists of a power plant (engine or electric motor), a clutch in manual transmission or a torque converter in automatic transmission, a gearbox (transmission), final drive, differential, drive shaft, and driven wheels. The torque and rotating speed from the output shaft of the power plant are transmitted to the driven wheels through the clutch or torque converter, gearbox, final drive, differential, and drive shaft. The clutch is used in manual transmission to couple or decouple the gearbox to the power plant. The torque converter in automatic transmission is a hydrodynamic device, functioning as the clutch in manual transmission with a continuously variable gear ratio (for more details, see Section 2.6). The gearbox supplies a few gear ratios from its input shaft to its output shaft for the power plant torque–speed profile to match the requirements of the load. The final drive is usually a pair of gears that supply a further speed reduction and distribute the torque to each wheel through the differential.
Mode switching analysis and control for a parallel hydraulic hybrid vehicle
Published in Vehicle System Dynamics, 2021
Shilei Zhou, Paul Walker, Yang Tian, Nong Zhang
The structure of the PHHV is shown in Figure 1 [2]. A hydraulic driving system is added on a traditional internal combustion engine powertrain. In the conventional engine powertrain, the engine output torque is transferred to wheels through the clutch, automated manual transmission (AMT), driveshaft, differential and halfshafts. The hydraulic driving system consists of a high-pressure accumulator, a low-pressure accumulator, a HPM and a control valve. Energy is stored in the high-pressure accumulator by compressing the inert gas. The swashplate in HPM is used to control the HPM working mode. The value of the HPM output torque is controlled through changing the swashplate angle. When the HPM works as a motor, the high-pressure oil flows from the high-pressure accumulator to the low-pressure accumulator and drives the driveshaft. Under braking conditions, the HPM switches to the pump mode. Oil is pumped from the low-pressure accumulator to the high-pressure accumulator so that the vehicle kinetic energy is recovered and stored in the high-pressure accumulator. To match the speeds of the HPM and vehicle drive shaft, an HPM gear is adopted. The HPM clutch is used to disengage the HPM from driveline under high vehicle speed to avoid the HPM overspeed.
Micro-analysis of a single vehicle driving volatility and impacts on emissions for intercity corridors
Published in International Journal of Sustainable Transportation, 2021
Elisabete Ferreira, Paulo Fernandes, Behnam Bahmankhah, Margarida C. Coelho
All measurements were carried out in fall 2018 in four different light duty diesel vehicles (c1–c4) with four different drivers (three males and one female, ages between 30 and 40 years old) to capture different driving styles. It must be noted that each driver drove always the same vehicle. The probe vehicles were equipped with a portable emission measurement system (PEMS), on-board diagnostic readers (OBD), and a Global Navigation Satellite System (GPS) data-logger, and driven along with the traffic stream by different persons for different driver behaviors. The testing vehicles vary in category, emissions standards, engine displacements, and mileage, as presented in Table 1. All vehicles have a five-gear manual transmission. Total data include 33 trips and approximately 26 000 sec of valid PEMS, OBD, and GPS data. For this research, the database consisted of 20 571 sec from 33 trips with a road coverage of approximately 355 km. Descriptive statistics are presented in Table 2, by vehicles and route. More details about the studied routes, experimental design, instruments and test conditions, field measurements and emission calculations can be found elsewhere (Fernandes et al., 2019b).
Design and feasibility analysis of a novel auto hold system in hydrostatic transmission wheeled vehicle
Published in Automatika, 2020
Lv Chang, Jianguo Dai, Shuo Liu
The driver model provided by AMESim software can be divided into two types: manual transmission driver model and automatic transmission driver model, respectively. In the present system, the driver model based on automatic transmission was adopted, as shown in Figure 7. The input port 3 of the module is speed control signal (m/s), input port 4 is actual speed signal of the vehicle (m/s), input port 2 is brake pedal opening signal (varying within 0∼1, 1 represents the maximum opening), input port 1 is accelerator pedal opening signal (varying within 0∼1, 1 represents the maximum opening).