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Mechanical devices that enables the driver shifting the pair of gearing wheels in such a way as to obtain the desired transmission ratio, are called shifting mechanisms.
This tutorial is intended to provide the user with some guidelines on modelling of gear shifting in gearboxes with parallel shafts by using MESYS Shafts System. Specifically, we will design a 3-speed gearbox consisting of spur gear stages.
Gear shifting operation. Shifting gears involves two orthogonal motions of the shift lever the “selection” stroke and the “shift” stroke: the shift rail is chosen in the “selection” stroke. in the “shift” stroke, a gear is synchronized and engaged. 1.
Gear trains are multiple sets of gears meshing together to deliver power and motion more effectively than can be accomplished by one set of gears. Figure 1 shows the various types of gears that can be used in a gear train. Gears 2 and 3 can be either spur or helical gears and are mounted on parallel shafts.
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- Ngo Dac Viet
- Gear Shift Strategies for Automotive Transmissions
- Introduction
- 1.1.1 History
- 1.3 Challenges
- Realtime gear shift strategy for automotive transmissions
- Consequences with respect to the gear shift and engine start events
- Publications
- Optimal Gear Shift Strategies for Conventional Vehicles1
- 2.1.2 Research Objectives
- g + Js r2
- 2.3.1 Driveability De nition
- 2.3.4 Method 3: The Variable Power Reserve
- Vehicle performance characteristics
- 2.4 Stochastic Gear Shift Strategy
- 2.4.3 Simulation Results and Discussions
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geboren te Thua Thien Hue, Vietnam Dit proefschrift is goedgekeurd door de promotor: prof.dr.ir. M. Steinbuch Copromotor: dr.ir. T. Hofman
The development history of automotive engineering has shown the essential role of transmissions in road vehicles primarily powered by internal combustion engines. The engine with its physical constraints on the torque and speed requires a transmission to have its power converted to the drive power demand at the wheels. Under dynamic driving conditi...
Abstract - In this chapter, some historical and technological trends of automotive transmis-sions used in road vehicles are brie y presented. Moreover, the background and scope of the dissertation are presented. In addition, the challenges related to the gear shift strategy design are discussed, which motivates the research objectives and scienti c...
Invention of the automobile and utilizing it as a means of transportation have made a great contribution to the growth of society. Automotive engineering and technology have always been subject to evolution. The current state of the art in vehicular propulsion systems is characterized by the following hierarchical interrelations: environment $ tra ...
The gear shift strategy for discrete ratio transmissions is a part of the supervisory control algorithm. The supervisory control algorithm generates for example the set points for the gear shift command based on the current powertrain states to improve the operation performance of the powertrain system. In this section, the basic dynamics of the po...
In order to drive the vehicle on road, a real time implementable gear strategy for the transmission is required. When the drive power request is totally unknown, a map-based gear shift strategy is a solution for determining when to shift gears online. A static gear shift map generates the shifting points, de ned as a point-wise function of the vehi...
Incorporation of the gear shift and engine start-stop strategies into an EMS for an AMT-based HEV in order to maximize the fuel economy bene t can result in: i) an earlier upshift pattern and a higher shifting frequency, and ii) a frequent stop and start of the engine. However, it should be noted that the gear shift or engine start-stop induces add...
In the research leading to this dissertation, the following journals and conference papers have been publishing.
Abstract - This chapter aims at designing optimal gear shift strategies for conventional pas-senger vehicles equipped with discrete ratio transmissions. The fuel economy and driveability are selected as the design objectives. Three methods of addressing the vehicle driveability are proposed for a fuel-optimal gear shift algorithm based on Dynamic P...
For discrete ratio transmissions, it can be observed that improving the fuel economy while not compromising the driveability is still a challenging research problem. There is lack of a proper method to analyze the correlation, and hence not able to de ne an optimal tradeo between the fuel economy and driveability through an optimal gear shift strat...
d + mvR2 w; and mv is the vehicle weight; Rw is the wheel radius; Je is the engine inertia; Jc is the clutch inertia; Jp is the transmission primary inertia; Js is the transmission secondary inertia; a is the air density; Af is the frontal area of vehicle; cd is the aerodynamic drag coe cient; cr is the rolling friction coe cient; g is the gravity ...
The fuel-optimal gear shift strategy, proposed in Section 2.2, yields an early and frequent upshift pattern for the transmission. It renders the engine, on average, to operate at a lower speed and high torque region, and hence improving the fuel economy. As a result, the so-called torque reserve Te, de ned by a di erence between the maximum engine ...
Both Methods 1 and 2 show that, the optimal gear shift strategy is sensitive to the weight factor and the power reserve limit Pe;lim, respectively. These design parameters are kept being constant for the whole drive cycle, and hence making the obtained gear shift strategy become more conservative. To overcome this drawback, the weight factor or the...
In this section, the discrete time variable k is left out of the variables for brevity. For the functional variables, the independent variable is omitted to improve the readability, for example rg := rg ng(k) . Then, if the engine output torque is Te, the propulsion force available at the wheels is given by, Fw = rg rd Te :
A gear shift strategy based on DP requires a knowledge of the whole drive cycle to obtain a globally optimal solution, thus making it not a realtime solution. Meanwhile a realtime implementable gear shift strategy can be achieved by utilizing Model Predictive Control (MPC) or Stochastic Dynamic Programming [11]. The MPC-based algorithm solves the o...
The gear shift strategy obtained from the stochastic control algorithm is a set of shift maps. Each shift map, corresponding to each velocity cluster vl, generates the shift points for the transmission based on the current gear position and the current power request. Therefore the SDP-based gear shift strategy can be directly implemented in simulat...
Gears are generally used for one of four different reasons: To increase or decrease the speed of rotation; To change the amount of force or torque; To move rotational motion to a different axis (i.e. parallel, right angles, rotating, linear etc.); and. To reverse the direction of rotation.
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Shifting Gears For Dummies. When you change gear, you shift the chain from one pair of sprockets to another. For cycling at speed, you'll use a larger sprocket on the pedal wheel. We talk you through how to use your bicycle gears efficiently and properly. The result is smoother, more precise shifting, as the mechanical difficulties.
