Charge balance simulations in commercial vehicles and related applications

Abstract

Modern commercial vehicles are increasingly being electrically loaded. As a result, there is increasing strain on the alternator and battery of the vehicle to deliver the subsequent electrical power to the electrical loads and to the starter motor during cranking. And with the advent of stricter emission norms, the number of after-treatment loads have also increased, thus further increasing the electrical power consumption in conventional vehicles. In such a case, during running conditions the alternator is expected to supply electrical power to the loads and also charge the battery. Since, during idling conditions the output of the alternator diminishes signi cantly, the chances of the battery discharging while supplying the loads are very high, which in turn will signi cantly reduce the capacity of the battery to supply power to the starter during cranking. This thesis is a study of the e ect of di erent loading patterns at di erent drive cycles on the charging capabilities of the alternator and amount of charge balance left in the battery after a drive cycle. A charge balance tool has been developed on MATLABSimulink and validated on a practical light commercial vehicle so as to test di erent ratings of alternators and batteries on di erent load settings at di erent drive cycles based on the vehicle type and its eld of application. The technical and nancial feasibility of novel methods like smart alternators and idle start-stop systems on the charge balance of batteries and the relief which it provides to alternators have also been explored and studied.