Energy Consumption Test and Analysis Methodology for Heavy-Duty Vehicle Engine Accessories

Fuel economy is a crucial parameter in long-haulage heavy-duty vehicles. Researchers tended to focus initially on engine combustion efficiency, while modern researchers turn their attention to the energy consumption of engine accessories in an attempt to enhance fuel economy. The accessories investigated in this study include the cooling fan, water pump, air compressor, power steering pump, air-conditioning (AC) compressor, and generator. Normally, accessory energy consumption analysis is based on rig data and simulation results. Here, we focus on the disparate test environments between the rig and vehicle to establish a novel constant power test method; the proposed method provides accurate accessory power data under different working conditions. A typical highway driving cycle is selected to collect accessory duty-cycle. The heavy-duty vehicle accessories' energy consumption distribution under highway road conditions is obtained through the repeated road tests. Accessories comprise energy consumption proportions of 4.7%-6.4% of the engine in winter and 10.3%12.6% in summer; they show different characteristics under different temperature or road conditions. The two influence factors of accessory energy consumption, constant power and duty-cycle, are analyzed to evaluate possible energy-saving schemes. Applying the clutch or electrical accessories, especially for the cooling fan and air compressor, is recommended.