Mobility and Vehicle Mechanics

7-26

Authors: Eid Mohamed

Most vehicle transmission systems control the ratio between engine speed and wheel speed using a fixed number of metal gears; the Continuously Variable Transmission (CVT) in currently available vehicles utilize a pair of variable-diameter pulleys connected by a belt or chain that can produce an infinite number of engine/wheel speed ratios for improve fuel consumption, drivability effectively, achieve both protection of earth environment and improvement vehicle performance sagging. The present research focuses on developing influence of loading conditions on the slip behavior and torque transmitting ability of the CVT. The model also investigates the range of clamping forces needed to initiate the transmission and to successfully meet the pressure requirements. The experimental setup and the instrumentation are present in detail; the measurement results are presented allowing for a more detailed description of the functional properties of the V-belt type variator, especially those related to reapply value of oil pressure by separate hydraulic unit and reduction ratio.

41-68

Authors: Ivan Dunđerski

The paper explores ways to increase effectiveness of vehicle acceleration. New solution has been given, based on the numerical control of engine torque using acceleration function. Natural engine torque is replaced by a curve of maximum efficiency of the engine torque, which passes through the torque maximums of partial engine charges. To control vehicle acceleration by the acceleration function torque controller is designed and connected to the engine electronic control unit (ECU). Programming code is written for controller operation. The study, that was conducted on an experimental vehicle, confirmed the feasibility of the numerical control of vehicle acceleration by the acceleration function with maximum torque effectiveness. Principal objective of this paper is how to improve engine torque effectiveness while vehicle accelerates in order to save fuel. The scope of investigation is replacing natural engine torque curve by a curve of maximal efficiency of the engine torque. Methodology employed in this paper is physical – mathematical model, computer simulation and processing, controller programming and experimentation. Vehicle acceleration employs custom designed controller by the acceleration function torque controller. Programming code is written for controller numerical operation. Experimental results and principal conclusions are that the control of vehicle acceleration by acceleration function saves fuel