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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.
Psychophysiological Test Methods and Procedures
Published in Samuel G. Charlton, Thomas G. O’Brien, Handbook of Human Factors Testing and Evaluation, 2019
The effects of overnight driving on drivers and passengers was measured using blink frequency and duration, steering wheel inputs, and subjective reports (Summala, Häkkänen, Mikkola, & Sinkkonen, 1999). The drivers drove 1,200 km during one night and rode as a passenger on the same route during another night. Eye blinks were monitored via video camera. Blink frequency increased with driving time, which indicated tiredness, and was higher when driving than when riding. Further, blink frequency decreased when the driving task became more difficult, such as when approached by oncoming trucks. Steering wheel inputs did not vary systematically. Zeier (1979) evaluated the merits of driving automobiles with manual or automatic transmissions in city conditions. Each of the 12 operators served as driver and passenger. Acting as driver and driving with the manual transmission were associated with greater adrenaline secretion and higher HR and HRV and more EDAs. These results were interpreted to show that automobiles with automatic transmissions were safer and less stressful to operate in city traffic than those with manual transmissions.
What Is a Tribosystem?
Published in J. Blau Peter, Tribosystem Analysis: A Practical Approach to the Diagnosis of Wear Problems, 2017
One example of a complex tribosystem whose subassemblies can be considered tribosystems in and of themselves is the automatic transmission in an automobile. A conventional automatic transmission consists of a torque converter, a planetary gearset, clutches and bands, and the fluid system, which includes a pump and the associated valve body. Any assembly of individual gears (triboelements) could be considered a tribosystem, as could a clutch, or a seal, or a set of bearings that operate within that transmission. If a particular gear might be more problematic than others, then it would be appropriate to narrow the tribosystem of interest to include that gear and the surrounding gear or gears that come into contact with it. In bench-scale laboratory testing, the definition of tribosystem is more straightforward: The tribosystem is the test apparatus, the materials and any lubricants within it, and the immediate surroundings.
Multi-objective optimization of gearshift trajectory planning for multi-speed electric vehicles
Published in Engineering Optimization, 2022
Kegang Zhao, Ziqi Li, Yuzhong Chen, Yanwei Liu
The use of electric vehicles (EVs) is an effective way to alleviate environmental and energy problems (Shin, Jung, and Oh 2017; Li et al.2018; Li, Khajepour, and Song 2019). EVs are typically equipped with single-speed transmissions, but these can hardly meet the increasing performance demand for EVs. Research shows that the application of multi-speed transmissions can effectively reduce energy consumption and considerably improve launching and acceleration performance (Urbina Coronado, Castañón, and Ahuett-Garza 2018; Liu et al.2020). For example, Sorniotti et al. (2011) demonstrated the potential advantages of a two-speed transmission for power performance and energy consumption. Among the various multi-speed transmissions, the dual-clutch transmission (DCT) has advantages such as high transmission efficiency and uninterrupted torque transfer (Walker, Zhang, and Tamba 2011; Berkel et al.2014). Thus, research on multi-speed transmissions for EVs has garnered substantial interest, and the application of the two-speed DCT in EVs is accordingly discussed in this article.
A review on fuel cell electric vehicle powertrain modeling and simulation
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Eda Alpaslan, Sera Ayten Çetinkaya, Ceren Yüksel Alpaydın, S. Aykut Korkmaz, Mustafa Umut Karaoğlan, C. Ozgur Colpan, K. Emrah Erginer, Aytaç Gören
In full electric or hybrid vehicles, there is a gear ratio between the differential output and the wheel due to the torque/speed characteristics of the vehicle traction motors. Electric vehicles are generally equipped with only a single-speed transmission in order to optimize the energy transmission system mass, volume, losses, and cost (KoteswaraRao and Naga Srinivasulu 2019; Sieklucki 2012). Another transmission type is the single-speed transmission with a clutch. This transmission type includes a clutch for the distribution of the power to two wheels. The transmission can be a clutch, continuously variable transmission (CVT), or a separate gearbox with a fixed reduction gear (Chan, Bouscayrol, and Chen 2010). The required engine torque and speed also change with the change of the performance characteristics of the vehicle such as the maximum slope and the load value (traction force) that it can carry. A 2-speed gearbox can be used to meet these performance characteristics by increasing the wheel torque at low vehicle speeds (Knodel, 2009). In addition, the use of a 2-speed gearbox can optimize the energy distribution and control energy consumption and motor efficiency. Another gear system used in electric vehicles shown in Figure 5b is the planetary gear system with the advantages of high efficiency, various reduction ratio, stress distribution by planetary gear, and compactness in the driving system design (Wang et al. 2019a).
An integrated chance-constrained stochastic model for efficient and sustainable supplier selection and order allocation
Published in International Journal of Production Research, 2018
Hadi Moheb-Alizadeh, Robert Handfield
The required items are in fact the forged parts of two shafts called primary shaft (PS) and secondary shaft (SS), i.e. v = 2. Due to the complex chemical combinations and high-tech manufacturing processes required for these items, the company succeeded in identifying only six potential domestic suppliers across the country, each of which has two price levels for each shaft, i.e. m = 6 and Li = 2 for . This manufacturing company produces three types of transmission systems; automatic transmission (AT), manual transmission (MT) and continuous variable transmission (CVT). In the manufacturing process, one primary shaft and one secondary shaft are assembled together in each type of transmission systems. All parameter values are presented in the file uploaded into Scribd (https://www.scribd.com/document/347776772/Empirical-Study-Data). These data are derived from historical records, which are mainly available in production planning and control department, purchasing department and quality control department of this manufacturing company.