Powertrain Matching for Better Fuel Economy

This paper discusses current powertrain matching methodology and its applications. Modular computer programs, which model each component of the vehicle/powertrain system, simulate the vehicle over specified driving cycles to project fuel economy and performance. Fuel economy opportunities due to better powertrain matching are discussed, including optimum engine sizing, torque converter matching, transmission gear ratio spacing and shift scheduling, axle ratio and vehicle weight effect. An emission projection technique utilizing time weighted engine speed/load points generated either by experiment or by analytical models is used to quantify fuel economy/emissions trade-offs.