Estimates of Critical Values of Aggressive Acceleration from a Viewpoint of Fuel Consumption and Emissions

The speed is a main factor to estimate macro amount of fuel consumption and emission of vehicles. However real time micro variation of fuel consumption and emission becomes important while the eco drive campaign to reduce fuel consumption and emission gets more concern. For this reason, the acceleration is becoming a more important factor. Although many studies have shown that acceleration is influencing factor for fuel consumption and emission, there are no consents what ranges of acceleration are defined as an aggressive acceleration in various driving conditions. This study tried to define the concept of aggressive acceleration and determine critical values of aggressive acceleration as influencing fuel consumption and emission significantly. The aggressive acceleration is defined where fuel consumption and emission rates increase rapidly while driving. The experiments are conducted on the drive testing site in South Korea using a passenger car fueling liquefied petroleum gas (LPG) and equipped with a driving data recorder. Testing vehicle speeds range from 10km/h to 80km/h considering driving patterns in urban areas. To depict fuel consumption and emission from the recorded data, regression models are developed and classification and regression tree (CART) analysis is used to find the critical values of aggressive acceleration. As a result, 1.4705 ㎨ and 2.2770 ㎨ are determined as estimates of aggressive acceleration and extreme aggressive acceleration, respectively.