There are three main groups who are interested in vehicle energy consumption, certifying bodies, system engineers, and component engineers. Certifying bodies need accurate power measurements to give the electrical mile per gallon (MPGe) efficiency certification of a vehicle. This number allows consumers and governing bodies to make decisions. Vehicle and system level engineers need to understand how the different components and subsystems perform so they can optimize the range of a vehicle. This is not just for powertrain, but all the subsystems that are also consuming energy. Lastly component level engineers need to be able to look at where losses are occurring and how to minimize them.
These types of vehicle range tests require a standardized torque and speed profile so that it can be a true standardization between vehicle ranges. The profiles, often referred to as drive cycles (figure 1), are a profile of speed vs time. The drive cycles have different speeds, accelerations, and decelerations to simulate “city” and “highway” miles.