Analysis of a New Form of Intrinsically Automatic Continuously Variable Transmission

2010 ◽  
Author(s):  
Timothy Cyders ◽  
Robert L. Williams
Keyword(s):  
Power Transmission ◽  
Mechanical Design ◽  
Peak Torque ◽  
Continuously Variable Transmission ◽  
Speed Ratio ◽  
Input Shaft ◽  
Positive Displacement ◽  
Variable Transmission ◽  
System Output ◽  
Human Powered

Effective continuously variable transmission (CVT) designs have been sought after for many years as their integration into many different mechanical systems can give many advantages over a discrete transmission system. Currently, CVTs are becoming popular for applications from automotive power transmission to wind power generation. Most CVT technologies, however, are friction- or hydraulic-based designs limited by both performance and system characteristics. This paper will evaluate a new, patented form of purely mechanical, intrinsically automatic CVT which is not based on belts, pulleys, gears or hydraulics. This new transmission is based on a deformable four-bar design incorporating a one-way clutch for positive displacement of the output. As torque demand on the system output is varied, the output’s displacement varies inversely to maintain a constant peak torque on the input shaft. The end result of this behavior is a possible instantaneous variation of speed ratio over an extreme range with a lightweight, simple mechanical design. This paper provides an analysis of the mechanism and its performance, as well as simulation results incorporating real-world measurement of system output into several different mechanical applications: a human-powered vehicle, an automobile and a centrifugal pump.

scholarly journals Real-Time Control Strategy for CVT-Based Hybrid Electric Vehicles Considering Drivability Constraints

2019 ◽  
Vol 9 (10) ◽  
pp. 2074 ◽  
Author(s):  
Hangyang Li ◽  
Yunshan Zhou ◽  
Huanjian Xiong ◽  
Bing Fu ◽  
Zhiliang Huang
Keyword(s):  
Real Time ◽  
Fuel Consumption ◽  
Electric Vehicles ◽  
Hybrid Electric Vehicles ◽  
Continuously Variable Transmission ◽  
Speed Ratio ◽  
Driving Pattern ◽  
Variable Transmission ◽  
Equivalent Factor ◽  
Hybrid Electric

The energy management strategy has a great influence on the fuel economy of hybrid electric vehicles, and the equivalent consumption minimization strategy (ECMS) has proved to be a useful tool for the real-time optimal control of Hybrid Electric Vehicles (HEVs). However, the adaptation of the equivalent factor poses a major challenge in order to obtain optimal fuel consumption as well as robustness to varying driving cycles. In this paper, an adaptive-ECMS based on driving pattern recognition (DPR) is established for hybrid electric vehicles with continuously variable transmission. The learning vector quantization (LVQ) neural network model was adopted for the on-line DPR algorithm. The influence of the battery state of charge (SOC) on the optimal equivalent factor was studied under different driving patterns. On this basis, a method of adaptation of the equivalent factor was proposed by considering the type of driving pattern and the battery SOC. Besides that, in order to enhance drivability, penalty terms were introduced to constrain frequent engine on/off events and large variations of the continuously variable transmission (CVT) speed ratio. Simulation results showed that the proposed method efficiently improved the equivalent fuel consumption with charge-sustaining operations and also took into account driving comfort.

Ratio Control Strategy for an Electromechanical Continuously Variable Transmission Based on Engine Models

2011 ◽  
Vol 291-294 ◽  
pp. 2861-2865 ◽  
Author(s):  
Qiang Jiang ◽  
Hong Yi Liu ◽  
Jian Jun Hao ◽  
Yue Cheng
Keyword(s):  
Pid Control ◽  
Control Algorithm ◽  
Continuously Variable Transmission ◽  
Speed Ratio ◽  
Vehicle Speed ◽  
Working Models ◽  
Special Character ◽  
Variable Transmission ◽  
New Type ◽  
Dynamical Coupling

Electromechanical control CVT (EM-CVT) is a new type of continuously variable transmission, and its ratio quality is an important parameter validated the performance of vehicle. In order to study the dynamical coupling technology between EM-CVT and engine under the running state of vehicle, the special character of two working models is obtained by engine experiment; according to the principle of the EM-CVT, the relation between vehicle speed and ration is theoretically analyzed. Based on the basic theory of PID control, the improved PID control algorithm is proposed for the speed ratio control of the EM-CVT, and experimental verification is made. The experimental results show that there is a significant effect on the system with this algorithm.

Theoretical Model of Metal V-Belt Drives During Rapid Ratio Changing

1999 ◽  
Vol 123 (1) ◽  
pp. 111-117 ◽  
Author(s):  
G. Carbone ◽  
L. Mangialardi ◽  
G. Mantriota
Keyword(s):  
Theoretical Model ◽  
Continuously Variable Transmission ◽  
Transient Condition ◽  
Speed Ratio ◽  
Dynamical Response ◽  
Rapid Variation ◽  
Axial Thrust ◽  
Belt Drives ◽  
Ratio Speed ◽  
Variable Transmission

Today the use of metal V-belt (MVB) on C.V.T. (continuously variable transmission) based systems is the rule in automotive applications. The great advantage of this kind of belt is the capability to resist the moving half-pulley’s high axial thrust necessary to transmit the large torque involved. This paper suggest a theoretical model of belt’s behavior during rapid ratio speed changes with the aim to represent the dynamical response of the system during the transient condition. The paper proposes a relation which correlates some easily measurable macroscopic quantities: axial thrust, torque transmitted and belt’s tensions on the slack and tight side. The metal V-belt consists of wedge-shaped plates that are supported by a flexible band, of which there are two types: the metal V-belt without clearance and the metal V-belt with clearance between plates. Our investigation is carried out for the first type of belt and under the hypothesis that there is a rapid variation of speed ratio. The result, that has been reached, allows to predict the behavior of the system and simplifies the planning of continuously variable transmission with metal V-belt.

Optimization of Hydraulic Pressure for Continuously Variable Transmission

2011 ◽  
Vol 317-319 ◽  
pp. 529-532
Author(s):  
Kei Lin Kuo
Keyword(s):  
Torque Converter ◽  
Transmission Efficiency ◽  
Gear Ratio ◽  
Continuously Variable Transmission ◽  
Hydraulic Pressure ◽  
Primary Input ◽  
Input Shaft ◽  
Variable Transmission ◽  
Labview Program ◽  
Set Up

Compared to conventional transmission layouts, Active continuously variable transmission (CVT) provides smoother gear shifting and gear ratio in smaller increments, and is, therefore, more accommodating the needs of both the driver and passengers. A few notable improvements are enhanced passenger comfort, higher transmission efficiency, and improved acceleration. Incorporating all of the above qualities has become a major developmental focus for the automotive industry, and the potential for improvement warrants further investigation. A CVT controls the gear ratio by changing the diameters of the primary (input) and the secondary (output) pulleys by adjusting the hydraulic pressure applied to each using valves. Hydraulic pressure in the channel is developed using a basic pump connected to the input shaft. Excess pressure produced at higher speed is wasted. This study aims to minimize this hydraulic pressure without affecting the transmission’s performance, in order to conserve energy. A user interface was set up and the CVT’s torque converter was modified such that the inner and outer shafts could be operated independently, allowing for full control of hydraulic pressure .This experiment successfully achieved, via a custom LabVIEW program, its goal of controlling the gear ratio between the primary and secondary pulleys whilst operating at lower pressures to those specified by the manufacturer. This proves that it is possible to fully control the CVT whilst operating at a reduced hydraulic pressure.

scholarly journals Intelligent Multiobjective Slip and Speed Ratio Control of a Novel Dual-Belt Continuously Variable Transmission for Automobiles

2014 ◽  
Vol 2014 ◽  
pp. 1-17
Author(s):  
Zhengchao Xie ◽  
Pak Kin Wong ◽  
Yueqiao Chen ◽  
Ka In Wong
Keyword(s):  
Analytical Model ◽  
Fuzzy Controller ◽  
Transmission Efficiency ◽  
Continuously Variable Transmission ◽  
Speed Ratio ◽  
Rule Base ◽  
Passenger Cars ◽  
Variable Transmission ◽  
Torque Capacity ◽  
Low Torque

Van Doorne’s continuously variable transmission (CVT) is the most popular CVT design for automotive transmission, but it is only applicable to low-power passenger cars because of its low torque capacity. To overcome this limitation of traditional single-belt CVT, a novel dual-belt Van Doorne’s CVT (DBVCVT) system, which is applicable to heavy-duty vehicles, has been previously proposed by the authors. This paper, based on the published analytical model and test rig of DBVCVT, further proposes an intelligent multiobjective fuzzy controller for slip and speed ratio control of DBVCVT. The controller aims to safely control the clamping forces of both the primary and the secondary pulleys in order to improve the transmission efficiency, achieve the accurate speed ratio, and avoid the belt slip under different engine loads and vehicle speeds. The slip, speed ratio, and transmission efficiency dynamics of DBVCVT are firstly analyzed and modeled in this paper. With the aid of a flexible objective function, the analytical model, and fuzzy logic, a Pareto rule base for fuzzy controller is developed for multiobjective DBVCVT control. Experimental results show that the proposed controller for slip and speed ratio regulation of DBVCVT is effective and performs well under different user-defined weights.

Sign in / Sign up

Export Citation Format

Share Document