Simple Prediction for Fuel Consumption and Cruising Distance of Internal Combustion Engine Vehicles with RFD Method

In order to develop various parts and components of vehicles, understanding the effects of their structures and thermal performance on the fuel consumption and cruising distance is important. However, because of the limited information available to parts suppliers, it is not always easy to predict and study vehicle fuel efficiency and cruising range performance under arbitrary driving conditions. In this study, the authors have developed an RFD (Regression Fuel-consumption Diagram) method to predict the cruising performance of internal-combustion engine vehicles (ICEV) based only on the published information given to suppliers by using standard reference vehicles, which had been regressed and identified for control characteristics and fuel consumption diagrams. As an example of the application of the RFD method to realistic situation, the effects of the driving mode and air-conditioning on the fuel consumption of ICEV are studied. Accordingly, it was found that the influence of the air-conditioning load on the fuel consumption differs depending on the driving modes. In addition, for the validation of the standard reference models introduced in the RFD method, the influence of changing the standard reference model on the simulation results of fuel consumption was investigated. As a result, it was found that the difference of the simulation results in fuel consumption was less than 1% even if the standard reference models was changed, which shows the present method is a robust model. Therefore, the accuracy of simulation results by the RFD method is sufficient to enable suppliers to predict roughly the cruising performance of ICEV.