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After the anti-skid brake system (ABS) introduction, mandatory for all vehicles in the Brazilian market, manufacturers have given increasing attention to optimized systems which meet legal and safety requirements. For commercial vehicles, an alternative for the ABS, which presents feasibility, is the configuration 4S/3M (4 wheel-speed sensors and 3 modulator valves) in substitution to the configuration 4S/4M. In other words, application of just one modulator valve to control the brakes of the same axle, front or rear, instead of independent control per each brake of the vehicle. The aim of this paper is to present a performance comparison between a brake system fitted with ABS configuration 4S/3M and an ABS configuration 4S/4M. To this end, both configurations were tested on the same vehicle application in accordance with the Brazilian legislation, CONTRAN 519/15.

Simulations tools like AVL Cruise and Vehicle Dynamics where used to carry on a comparative study between two trucks equipped with automated manual transmissions in two configurations: the original with 12 gears, and a proposal with 16 gears. The original configuration is world-wide used and in this way, the present study was fundamental to decide whether choosing the new proposal would bring the Brazilian option any advantages. In order to evaluate the whole vehicle behavior fuel consumption evaluation and vehicle performance were analyzed. From the present study, it was showed that the 16 gears transmission was the best alternative for the Brazilian application.

Evaluation of vehicle performance is one of the most important phases of the new vehicle development. Start Ability and Top Speed are factors that are noticed by users, therefore are very important to the final product. Vehicle performance evaluation has been largely benefited from the use of simulation tools. In fact, MAN Latin America (ML) employs simulation programs to evaluate the performance of its vehicles (trucks and buses) achieving good results. However, those programs are normally “closed codes” which makes difficult the physical comprehension of results. Altogether, this article presents Vehicle Dynamics, a macro developed by ML engineering team. The aim of this macro is the automatic calculation of Start Ability, Grade Ability, Top Speed, among other performance parameters.