Braking System Design for Passenger Cars and Light Vans

This chapter introduces the basic theory for the high-level design of braking systems for any road vehicle of a rigid configuration, i.e. passenger car, light van and solo commercial vehicle (bus and truck without trailer). The analyses, based on a two-dimensional model (although lateral forces and effects are also considered), show how dynamic weight transfer from the rear axle(s) to the front axle occurs, being dependent on the vehicle design and its deceleration. An overview of the nature of tyre/road adhesion is given, and the relationship between the braking force generated at each wheel and the ‘slip’ of that wheel is explained and discussed. The parameters ‘adhesion utilisation’ and ‘braking efficiency’ are used to determine the front/rear axle braking ratio from which the braking system can be designed in detail, as explained in Chapter 6 . This approach ensures that premature rear wheel lock and consequent vehicle dynamic instability do not occur in the basic braking system design configuration.