Economic Driving Strategy for Commercial Vehicles in Mountainous Areas

Steep and long slope is an obvious characteristic of mountainous highways. Unreasonable acceleration or deceleration of the vehicles on the slopes will increase the fuel consumption. Improving the performance of the engine or the transmission system has limited energy saving potential, and most fuel-efficient driving assistant systems don’t consider the road conditions. The main purpose of this paper is to introduce an economic driving strategy to optimize vehicle speed profile for commercial vehicles traveling in mountainous areas with consideration of future road conditions. Economic driving strategy based on the energy conservation principle can adapt to various vehicles due to its less dependence on the engine fuel consumption characteristics. The engine brake performance measurement based on the vehicle longitudinal dynamics is achieved by analyzing the vehicle state information during transportation, which reduces the test times in the laboratory or the proving ground. Economic driving strategy will plan optimal speed profiles for commercial vehicles with consideration of future road conditions before the vehicles reach the slopes. Economic driving strategy guides the drivers to adjust vehicle speed reasonably, distribute effectively braking distance of the engine brake and the friction brakes on the slopes. The engine output energy and the brake energy loss can be reduced for improving the vehicle energy utilization rate when the drivers follow economic driving guidance. Semi-physical simulations were carried out to validate the effectiveness of economic driving strategy. The simulation results showed that economic driving strategy could increases the fuel economy by 3.4% to 5.5% averagely compared with the drives without economic guidance. The transportation cost and the abrasions of the friction brakes will be effectively reduced when economic driving strategy is applied to advanced driving assistance systems.