Application of the Power-Based Fuel Consumption Model to Commercial Vehicles

Fuel power consumption for light duty vehicles has previously been shown to be proportional to vehicle traction power, with an offset for overhead and accessory losses. This allows the fuel consumption for an individual powertrain to be projected across different vehicles, missions, and drive cycles. This work applies the power-based model to commercial vehicles and demonstrates its usefulness for projecting fuel consumption on both regulatory and customer use cycles. The ability to project fuel consumption to different missions is particularly useful for commercial vehicles, as they are used in a wide range of applications and with customized designs. Specific cases are investigated for Light and Medium Heavy- Duty work trucks. The average power required by a vehicle to drive the regulatory cycles varies by nearly a factor 10 between the Class 4 vehicle on the ARB Transient cycle and the loaded Class 7 vehicle at 65 mph on grade. The results show a striking linearity for the fuel power over this wide range of driving conditions. The model predictions are validated by comparing laboratory measurements with detailed numerical simulation models such as EPA’s Greenhouse Gas Emissions Model (GEM) and on-road vehicle measurements. The method and the insights gained may be useful in defining future truck fuel economy goals and certification requirements.