Modeling,Simulation and Control of Continuously Variable Transmission (CVT) systems

Problem Motivation

In the past few years, the Automotive Engineers are continuously exploring various engines, transmission, and chassis technologies to increase the overall vehicle performance, fuel economy and safety. One such promissing powertrain concept is the Continuously Variable Transmission (CVT), which offers a continuum of infinitely variable gear ratios between established minimum and maximum limits.

The Continuous gear ratio spectrum in CVT can increase the overall powertrain efficiency and eliminate the unwanted jerks that are associated with the manual and automatic transmission.

A hybrid Power split continuously variable transmission configuration offers both fixed gearing and adjustable pulleys to satisfy demands. The effective control of the variable radius pulleys allows the designation of engine torque/speed to improve overall system performance for a given operating condition.

Research Objectives

  Develop a complete CVT Model.

  Power Split CVT.

  Belt Dynamics.

  Sheave Actuation with hydraulic fluid.

  Accompanying Powertrain and Chassis model.

  Conventional spark ignition engine model.

  Driveline and chassis models.

  Modules for ARCSim and ADVISOR software tools.

  Verify Models through experimental testing.

  Engine subsystem.

  CVT and driveline subsystems.

  Design integrated CVT and engine control control algorithms.

  Simple integrator describes CVT dynamics.

  Detailed model of CVT kinematics and hydraulics.

Control Strategy

Simplified System Model

Simulation Results

Fig. 1 Simulation 1

Fig. 2 Simulation 2

Fig. 3 Simulation 3

Fig. 4 Simulation 4

References
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