Continuously Variable Transmission (CVT) Fuel Economy

2017 ◽  
Author(s):  
Yungwan Kwak ◽  
Christopher Cleveland
Keyword(s):  
Fuel Economy ◽  
Continuously Variable Transmission ◽  
Variable Transmission

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.

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

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.  

Control of a Flywheel Assisted Driveline With Continuously Variable Transmission

2003 ◽  
Vol 125 (3) ◽  
pp. 455-461 ◽  
Author(s):  
Alex F. A. Serrarens ◽  
Shuiwen Shen ◽  
Frans E. Veldpaus
Keyword(s):  
Internal Combustion Engine ◽  
Simulation Model ◽  
Nonlinear Model ◽  
Fuel Economy ◽  
Feedback Linearization ◽  
Combustion Engine ◽  
Control Design ◽  
Continuously Variable Transmission ◽  
Control Solution ◽  
Variable Transmission

This paper proposes a control solution for a vehicular driveline with an internal combustion engine, a continuously variable transmission and an additional flywheel unit. This unit plays a part only in transient situations. It compensates for the engine inertia, enabling optimal fuel economy in stationary situations without losing driveability during transients. For control design, a simple, nonlinear model is developed and used for feedback linearization. The proposed controller is evaluated by simulations, using an advanced simulation model. The compensation of the engine inertia by the additional flywheel is demonstrated by vehicle experiments.

scholarly journals Effective optimal control strategy for hybrid electric vehicle with continuously variable transmission

2019 ◽  
Vol 11 (3) ◽  
pp. 168781401882481 ◽  
Author(s):  
Hangyang Li ◽  
Xiaolan Hu ◽  
Bing Fu ◽  
Jiande Wang ◽  
Feitie Zhang ◽  
...  
Keyword(s):  
Cost Function ◽  
Electric Vehicles ◽  
Fuel Economy ◽  
Control Strategy ◽  
Hybrid Electric Vehicle ◽  
Hybrid Electric Vehicles ◽  
Continuously Variable Transmission ◽  
Optimal Control Strategy ◽  
Variable Transmission ◽  
Hybrid Electric

Hybrid electric vehicles equipped with continuously variable transmission show dramatic improvements in fuel economy and driving performance because they can continuously adjust the operating points of the power source. This article proposes an optimal control strategy for continuously variable transmission–based hybrid electric vehicles with a pre-transmission parallel configuration. To explore the fuel-saving potential of the given configuration, a ‘control-oriented’ quasi-static vehicle model is built, and dynamic programming is adopted to determine the optimal torque split factor and continuously variable transmission speed ratio. However, a single-criterion cost function will lead to undesirable drivability problems. To tackle this problem, the main factors affecting the driving performance of a continuously variable transmission–based hybrid electric vehicle are studied. On that basis, a multicriterion cost function is proposed by introducing drivability constraints. By varying the weighting factors, the trade-off between fuel economy and drivability can be evaluated under a predetermined driving cycle. To validate the effectiveness of the proposed method, simulation experiments are performed under four different driving cycles, and the results indicate that the proposed method greatly enhanced the drivability without significantly increasing fuel consumption. Compared to a single-criterion cost function, the use of multiple criteria is more representative of real-world driving behaviour and thus provides better reference solutions to evaluate suboptimal online controllers.

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