Benefits of Electronic Assisted Variable Geometry Turbocharging on Sports Utility Vehicle

Turbocharging of diesel engines have undergone various phases of technological advancements proving merits with engine performance. Since VGTs are finding their applications in many automotive engines, it is also crucial on finding out ways to extract maximum benefits from the system. Pneumatic actuated VGTs control the vanes positioning with the help of mechanical linkages and don’t prove good in transient response with relatively slower boost build up. The electronic controlled VGT operates with the aid of DC motor which is linked to the engine management system. The position sensor senses the current position of the actuator which is controlled by the engine management system for delivering the desired boost pressure. The eVGT system thus provides very quick response and accurate control of boost pressure in all the vehicle driving conditions. The mechanical losses and wear of the pneumatic system could not account for the dynamic response of boost pressure, but the wear detection is enhanced in the eVGT through the offset learning. The cushioning of the mechanical stop position is provided. Improvement in engine out emissions was possible with eVGT in comparison with the pneumatic controlled system. Drivability of the vehicle was greatly enhanced with negligible effect of turbo lag and high transient response. This paper examines the advantages of electronic VGT in comparison with pneumatic VGT with respect to performance, emissions and drivability factors with all the supporting results of the same.