Estimating Automobile Chassis Voltage Distortion Using Load Currents

Modern automobiles incorporate more actuators, heaters, and other electrical loads than have automobiles in the past. This proliferation of high current, high power loads is presently challenging the longstanding assumption that the entire chassis will remain at one potential under a variety of different operating conditions. New voltage standards, alternator designs, and power electronics ensure that sufficient electrical power will be available for next-generation automotive loads [l], [2]. This paper considers the less obvious problem of transient voltage distortion resulting from load currents in the automobile chassis. The model and methods developed in this paper could help designers avoid problems related to high-power loads and may be useful for locating intermittent shorts and other faults. The structure of the chassis plays a pivotal role in the automobile electrical system. Most loads in the automobile are connected as illustrated in Fig. 1. Current is carried by wires from the positive terminal of the battery to the loads distortion prediction in a “body-in-white” Ford Sable automobile Chassis.