Adaptive Economy Drive Mode Algorithm Development for Fuel Efficient Operation in Light Commercial Vehicle

In Commercial vehicles, during the transit of goods for delivery the vehicle is in laden condition and after delivery it returns in unladen condition. The engine is designed and calibrated to get good drivability in Gross Vehicle Weight (GVW) of the vehicle. When the vehicle is driven at unladen condition or partially laden condition, the vehicle is accelerated very high due to higher torque available from engine, leading to excessive fuel consumption. In some commercial vehicle models, Economy Drive mode option is available, in which the maximum torque delivered by engine is tapered to one level down to achieve better fuel economy. But in GVW condition with Economy Drive mode the driver may not feel the acceleration response and he tend to switch to Power mode. This technical paper describes Adaptive Economy Drive Mode algorithm development which operates with sufficient acceleration using optimum fuel. In Adaptive Economy Drive mode, there are 3 phases. The first phase is to sense or predict the load carried by the vehicle, based on the operating point of engine and gear ratio selected, the vehicle load is determined using the load prediction algorithm and the load index factor is derived. The second phase is to determine the required torque to carry the load using data-driven model arrived from instantaneous coast down of the vehicle and load index factor. The third phase is to apply the proportional torque limit to the engine with close-loop control. When the optimum torque limit is applied, the torque band available for the vehicle to accelerate will always remain in optimum band, leading to best Performance Vs Fuel economy trade-off zone operation of the vehicle.