With rapid improvement in the road infrastructure the average turnaround time of the cargo vehicles has been reduced by 25%.New generation commercial vehicles has better power to weight ratio by integrating high horse power engines. With this latest vehicle configuration average speed of fleet is increased by 30% and more focus is provided towards vehicle safety and handling. Driver confidence on vehicle handling improves with better on Centre feel and return ability, these two parameters are easily tunable with modern electric power assisted steering system, whereas with hydraulic power assisted system these parameters optimization have adverse effect on other steering performance. This paper covers study of following parameters of hydraulic assisted steering system and its optimization on vehicle handling.
1. Steering Gearbox torsion bar stiffness
2. Steering pump flow
3. Caster angle
4. Steering Gearbox valve curve
5. Steering components compliance
Base vehicle level objective measurements is carried out to set the acceptance criteria. Above parameters optimization done in isolation and in combination, rig trails conducted to have optimized combination. Following this vehicle performance trials carried out to verify the improvements. These techniques can be used for enhancing vehicle handling of hydraulic power steering assisted commercial vehicles.