共查询到20条相似文献,搜索用时 15 毫秒
1.
A modified CVT ratio map is proposed to obtain the improved fuel economy for a metal belt CVT. Since the CVT system loss,
which occupies most of the drivetrain loss, depends on the engine speed, input torque, primary and secondary actuator pressure,
a modified CVT ratio map is produced to realize the highest engine-CVT overall efficiency through the consideration of CVT
system loss. The modified CVT ratio map is constructed with respect to the demanded vehicle power and present vehicle speed
based on the steady state CVT system loss. Using the modified CVT ratio map, performance simulations are carried out using
the dynamic models of the CVT powertrain. The simulation results indicate that the modified CVT ratio control provides improved
engine-CVT overall system efficiency, and improves the fuel economy of the federal urban driving schedule by 4.9 percent. 相似文献
2.
3.
C. Zhu H. Liu J. Tian Q. Xiao X. Du 《International Journal of Automotive Technology》2010,11(2):257-261
Because of their outstanding advantages over other transmissions, rubber V-belt pulley drive CVTs have been extensively used
in low-power vehicles, such as scooters and snowmobiles. A rubber V-belt CVT installed on a snowmobile is used here to research
transmission efficiency. The power loss of CVTs, including torque loss and speed loss, is studied based on an analysis of
the transmission mechanism of CVTs. Experiments on CVT efficiency are conducted on a specific CVT test bench, on which the
values of torque, speed, and displacement, etc., are measured. Results show that the variation trend of the efficiency is
close to the operating conditions of CVTs and optimal structural parameters are given that can serve as a beneficial references
for designing and tuning CVTs. 相似文献
4.
《JSAE Review》2002,23(2):213-217
A double cavity half-toroidal CVT has two variators, which gives a hint of a new four-wheel drive without a center differential gear unit by applying each of them to drive front and rear drive shafts independently. Torque re-circulation at cornering or different tire radii between front and rear tire is avoided by compensating the speed ratio of variator. The controller adjusts the attitude angle of power roller of the front variator against the rear by measuring the steering angle at cornering. This paper describes the speed ratio control system of the 4WD-CVT with speed ratio range of 1 : 8.7 and test results of vehicle motion mounted on a 3.2L RV. 相似文献
5.
全电调节橡胶带式CVT的试验研究 总被引:1,自引:0,他引:1
在分析现有带式CVT调节方式优缺点的基础上,提出了一种采用双电机分别调节主、从动带轮工作半径以实现速比变化的全电调节方式,并以橡胶V型带CVT为应用对象研制了首台全电调节CVT样机.通过台架试验对样机进行测试.得到了其速比与执行电机转角的对应关系以及不同速比下其传递转矩和传递效率随带轮动盘夹紧力的变化规律,从而验证了全电调节无级变速的可行性. 相似文献
6.
7.
8.
9.
Arian Afrabandpey Hashem Ghariblu 《International Journal of Automotive Technology》2018,19(3):547-557
This study aims at finding an analytical model of ball continuously variable transmission (B-CVT) behavior and performance, based on the existing model of the half-toroidal traction drive. The geometrical and kinematical aspects of this model have been found. Then, force-moment equilibrium equations have been applied for a B-CVT. The contact behavior has been modeled using the isothermal elastohydrodynamic lubrication (EHL) theory, and spin and relative slip losses have been estimated for this CVT. Finally, the overall efficiencies of the B-CVT have been analyzed and compared with the halftoroidal traction drive. This study results have shown that B-CVT has higher torque efficiency and lower speed efficiency in comparison with half-toroidal CVT. Also, it has shown that the adjustment of axial forces in B-CVT leads to higher efficiency in lower input torques. 相似文献
10.
借用Shinya Kuwabara和Toru Fujii建立起的CVT功率传递的数学模型,分析了CVT各部件的受力情况,确定了各个分力之间的关系式。在此基础上,分析了CVT的滑移特性,对金属带与金属块之间以及金属块与带轮之间的滑移作了详细的分析,为确定合适的带轮夹持力提供了理论依据。 相似文献
11.
12.
13.
14.
《JSAE Review》1995,16(3):251-256
We have developed a continuously variable transmission (CVT) which has superior transfer efficiency, by thoroughly reducing transfer loss by means of using a dry hybrid belt, using no lubrication composition system around the belt, and using an electric control system of a DC motor.The fuel efficiency and driveability of the prototype vehicle equiped with the CVT were proven equivalent or even superior to a 5 speed manual transmission. 相似文献
15.
16.
In this paper, with the parameters acquired from measured and tested data, a three-phase mathematical model is applied to
the motor component of the developed electromagnetic suspension actuator. A main/inner-loop structure is used for its active
control, and the constraints of the control current and energy flow states of actuator are analyzed by simplifying the inner-loop
control system. Two different control modes, i.e., Consumptive Full Active (CFA) and Regenerative Semi Active (RSA) modes,
which emphasize vibration control of sprung mass and vibration energy regeneration caused by road roughness, respectively,
are proposed. Simulations are carried out using different road conditions, and the results demonstrate that the CFA mode can
improve vehicle ride comfort by more than 30 percent, despite battery energy consumption; in RSA mode, the ride comfort can
be improved by up to 10 percent with the battery charged by regenerated energy. 相似文献
17.
Liang-Kuang Chen A. Galip Ulsoy 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2006,44(3):223-245
Human-in-the-loop driving simulator experiments are conducted to evaluate a proposed robust steering assist controller that is designed on the basis of driver uncertainty modelling. A nominal controller (NC) that is designed without consideration of driver model uncertainty is also tested for comparison. Two types of experiments are proposed: a long driving task with nominal configurations and a short driving task with initially large lateral position error. The data are analysed using both time domain and frequency domain metrics. In the time domain, the standard deviation of lateral position error and percentage of road departure are used. In the frequency domain, the stability margins and crossover frequency are used. The driving simulator results indicate that statistically, the designed robust controller shows improvements in the short driving experiments. The improvements in the long driving experiments are less evident because of driver adaptation. The non-robust NC suffers from high gain and should be avoided. The benefits of considering driver model uncertainty in the design of vehicle steering assist controllers are, therefore, justified. 相似文献
18.
Continuously Variable Transmission (CVT) is one of the most promising automotive transmission technologies because of its
continuously variable gear ratio and reduced shift shock. CVT is different from Manual Transmission and Automatic Transmission,
and it is possible to operate the power source in its high efficiency region with CVT in the drive train. Several types of
CVT exist that can be categorized based on the mechanism of power transmission, such as the belt pulley, traction drive, and
hydrostatic types. This paper investigates the belt pulley CVT, which consists of a thrust actuator, driver pulley, belt,
driven pulley, and preload spring of the output shaft. A complete CVT is constructed, and based on that a simulation program
that analyzes the static performance of a CVT is implemented in Matlab/Simulink. From these simulation results, methods for
improving the efficiency of the CVT are discussed. The coefficient of the torque capacity factor is proposed as affecting
the matching between a power source and a CVT, and methods for improving the matching effect are also investigated. 相似文献
19.
20.
The objective of this research is geometrical and kinematical optimization of full-toroidal continuously variable transmission (CVT) in order to achieve high power transmission efficiency and low mass. At first, a dynamic analysis is performed for the system. A computer model is developed to simulate elastohydrodynamic (EHL) contact between disks and roller and consequently, calculate CVT efficiency. The validity of EHL model is investigated by comparing output of this model and experimental data. Geometrical parameters are obtained by means of Particle Swarm Optimization algorithm, while the optimization objective is to maximize CVT efficiency and minimize its mass. The algorithm is run for different values of selected input parameters that are oil temperature, roller tilting angle (speed ratio). Optimization results show that optimized geometrical parameters are approximately constant for various values of input parameters. Also, it is observed that, increasing values of oil temperature and roller tilting angle (in clockwise direction), will decrease power transmission efficiency. An average power transmission efficiency of 86.7% is achieved over a wide range of input parameters, using optimized geometry. 相似文献