APPLICATION OF DISC SPRING IN CLAMPING FORCE MECHANISM FOR ELECTRO-MECHANICAL CONTINUOUSLY VARIABLE TRANSMISSION

2015 ◽  
Vol 77 (22) ◽  
Author(s):  
Izhari Izmi Mazali ◽  
Kamarul Baharin Tawi ◽  
Bambang Supriyo ◽  
Mohd Sabri Che Kob ◽  
Nurulakmar Abu Husain ◽  
...  
Keyword(s):  
High Power ◽  
Fuel Economy ◽  
Continuously Variable Transmission ◽  
Clamping Force ◽  
Actuation System ◽  
Variable Transmission ◽  
High Power Consumption ◽  
Force Mechanism ◽  
Compact Design ◽  
Disc Spring

Pulley-based continuously variable transmission (CVT) with metal pushing V-belt (V-belt) offers tremendous potentials in the fuel economy of the car due to its wide and continuous ratio coverage. Nevertheless, the existing pulley-based CVTs in automotive markets use electro-hydro-mechanical (EHM) actuation system to vary its ratio and to provide sufficient clamping force on the V-belt. This, unfortunately, leads to a significant high power consumption from the engine of the car which eventually worsens the car’s fuel economy. To address this issue, researchers introduce electro-mechanical CVT (EM CVT) in which the application of the EHM actuation system is replaced by an electro-mechanical (EM) actuation system. This paper discusses the application of disc spring in clamping force mechanism of EM CVT. The selected disc spring is analyzed and evaluated to prove its workability for CVT’s application. The analysis results indicate that the application of disc spring in clamping force mechanism of EM CVT is possible and it also offers some benefits particularly in term of its compact design.  

Indirect Clamping Force Measurement Method Using Current Sensor for Electro-Mechanical Dual Acting Pulley Continuously Variable Transmission System

2014 ◽  
Vol 663 ◽  
pp. 238-242
Author(s):  
Bambang Supriyo ◽  
Kamarul Baharin Tawi ◽  
Mohd Salman Che Kob ◽  
Izhariizmi Mazali ◽  
Yusrina Zainal Abidin
Keyword(s):  
Positive Impact ◽  
Force Sensor ◽  
Dc Motor ◽  
Continuously Variable Transmission ◽  
Current Sensor ◽  
Clamping Force ◽  
Primary Input ◽  
Motor Current ◽  
Actuation System ◽  
Variable Transmission

This paper introduces an electro-mechanical dual acting pulley continuously variable transmission (EMDAP CVT) system and presents a method of measuring belt-pulley clamping force indirectly using a DC motor current sensor. The EMDAP CVT mainly consists of two movable primary (input) and secondary (output) pulley sheaves connected by metal pushing V-belt. Two DC motor’s actuation systems adjust the CVT ratio. Additionally, the secondary actuation system controls belt-pulley clamping force by adjusting the flatness of the spring discs placed at the back of each secondary pulley sheave to keep the belt tight and prevent belt slip. Ideally, a force sensor is used to measure the belt-pulley clamping force however the use of force sensor inside transmission gearbox is not feasible due to high temperature and oily environment. A viable solution for indirectly measuring the clamping force using current sensor for DC motor is proposed. Since the DC motor actuates the movable pulleys to clamp the belt, the relationship between the DC motor current and belt-pulley clamping force can then be investigated experimentally. The results will give positive impact on precisely controlling belt-pulley clamping force of EMDAP CVT using current sensor which is relatively simpler and less expensive than force sensor.

Pulleys' Axial Movement Mechanism for Electro-Mechanical Continuously Variable Transmission

2014 ◽  
Vol 663 ◽  
pp. 185-192 ◽  
Author(s):  
Kamarul Baharin Tawi ◽  
Izhari Izmi Mazali ◽  
Bambang Supriyo ◽  
Nurulakmar Abu Husain ◽  
Mohd Salman Che Kob ◽  
...  
Keyword(s):  
Continuously Variable Transmission ◽  
Hydraulic Pressure ◽  
Actuation System ◽  
Powertrain System ◽  
Axial Movement ◽  
Variable Transmission ◽  
Movement Mechanism ◽  
Potential Benefits ◽  
High Power Consumption ◽  
Axially Moving

Pulley-based continuously variable transmission (CVT) with Metal Pushing V-belt (V-belt) is a type of automotive transmission that is widely applied currently by many car manufacturers worldwide. Unlike the conventional automotive transmissions, in a pulley-based CVT with V-belt, the transmission ratio (CVT ratio) is changed continuously without the use of discrete gears. Instead, the CVT ratio is varied through the simultaneous axial movement of the primary pulley and the secondary pulley. By axially moving both pulleys simultaneously, the radius of the V-belt on both pulleys will be changed accordingly, resulting in the change of the CVT ratio. The existing pulley-based CVTs in the market use electro-hydro-mechanical (EHM) actuation system to change and to maintain the desired CVT ratio through the hydraulic pressure. However, the application of EHM actuation system leads to some disadvantages, particularly in term of the high power consumption from the engine needed to maintain the desired CVT ratio. This reduces the efficiency of the powertrain system, which eventually increases the fuel consumption of the vehicles. In addition to that, the existing pulley-based CVTs also use single acting pulley mechanism to axially move the pulleys for changing the CVT ratio. Therefore, the issue of V-belt's misalignment, which shortens the lifespan of the V-belt, is inevitable here. In this paper, the pulleys' axial movement mechanism that uses electro-mechanical (EM) actuation system is proposed. Consequently, the working principle of the proposal is described and its potential benefits are discussed.

Improvement of fuel economy by shift speed control for a metal belt continuously variable transmission

2002 ◽  
Vol 216 (9) ◽  
pp. 741-749 ◽  
Author(s):  
H Lee ◽  
H Kim
Keyword(s):  
Fuel Economy ◽  
Dynamic Models ◽  
Control Valve ◽  
Speed Control ◽  
Pressure Control ◽  
Continuously Variable Transmission ◽  
Hydraulic Loss ◽  
Variable Transmission ◽  
Line Pressure ◽  
Shift Speed

In this paper, an algorithm to improve the fuel economy of a metal belt continuously variable transmission (CVT) vehicle by CVT shift speed control is suggested. By rearranging the CVT shift dynamic equation, it is found that the CVT shift speed depends on the line pressure as well as on the primary pressure. CVT shift speed maps are constructed to evaluate the influence of the line pressure on the shift speed. To obtain a target shift speed, an algorithm to calculate the line pressure is presented. In order to estimate the shift speed and the hydraulic loss, dynamic models of the line pressure control valve and the ratio control valve are obtained by considering the CVT shift dynamics and validated by experiments. It is found from the simulation results that fuel economy can be improved by 2 per cent in spite of the increased hydraulic loss due to the increased line pressure.

Design of Control System for Automotive CVT Based on ATmega164P MCU

2012 ◽  
Vol 479-481 ◽  
pp. 1897-1900
Author(s):  
Yue Cheng
Keyword(s):  
Control System ◽  
Force Control ◽  
Hydraulic System ◽  
Continuously Variable Transmission ◽  
Clamping Force ◽  
Single Chip ◽  
Rotating Speed ◽  
Position Signal ◽  
Single Chip Computer ◽  
Variable Transmission

Control system and some functional circuits of automotive CVT (Continuously Variable Transmission) based on ATmega164P single chip computer were introduced in this paper. Hydraulic system of the CVT was controlled according to the throttle position signal, oil pressure, rotating speed of the engine and transmission output speed etc. This system has achieved the clamping force control of the metal belt.

Development of Continuously Variable Transmission Fluid for Fuel Economy

2013 ◽  
Author(s):  
Takahiro Fukumizu ◽  
Minoru Yamashita ◽  
Masashi Ogawa ◽  
Junichi Nishinosono ◽  
Takehisa Sato ◽  
...  
Keyword(s):  
Fuel Economy ◽  
Continuously Variable Transmission ◽  
Variable Transmission ◽  
Transmission Fluid

A Validated Modular Model for Hydraulic Actuation in a Pushbelt Continuously Variable Transmission

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Stan van der Meulen ◽  
Rokus van Iperen ◽  
Bram de Jager ◽  
Frans Veldpaus ◽  
Francis van der Sluis ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
First Principles ◽  
Closed Loop ◽  
Low Complexity ◽  
High Accuracy ◽  
Continuously Variable Transmission ◽  
Design Parameters ◽  
Actuation System ◽  
Modular Model ◽  
Variable Transmission

A reduction in the fuel consumption of a passenger car with a pushbelt continuously variable transmission (CVT) can be established via optimization of the hydraulic actuation system. This requires a model of the dynamic characteristics with low complexity and high accuracy, e.g., for closed-loop control design, for closed-loop simulation, and for optimization of design parameters. The hydraulic actuation system includes a large number of hydraulic components and a model of the dynamic characteristics is scarce, which is caused by the complexity, the nonlinearity, and the necessity of a large number of physical parameters that are uncertain or unknown. In this paper, a modular model for the hydraulic actuation system on the basis of first principles is constructed and validated, which is characterized by a relatively low complexity and a reasonably high accuracy. A modular approach is pursued with respect to the first principles models of the hydraulic components, i.e., a hydraulic pump, spool valves, proportional solenoid valves, channels, and hydraulic cylinders, which reduces complexity and improves transparency. The model parameters are either directly provided, directly measured, or identified. The model of the hydraulic actuation system is composed of the models of the hydraulic components and is experimentally validated by means of measurements that are obtained from a production pushbelt CVT. Several experiment types are considered. The correspondence between the measured and simulated responses is fairly good.

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