Brushless Fast Starter for Automotive Engine Start/Stop Application

In this article, a 48 V, 4 kW brushless fast starter (BFS) system for automotive start/stop applications is presented. The design and analysis of the machine, inverter, controller, and control algorithm are discussed in detail. The inverter and motor are integrated within the same size housing as the original brush-type starter to enable a drop-in replacement. Simulation models were used to assess the performance benefits of the brushless drive during engine autostart events and key start were compared to the conventional starting system with brush-type dc motors. To further verify the concept, a prototype BFS system was built. Both conventional 12 V brushed and proposed brushless starter were first tested on two different engine start carts. The performance in terms of autostart time, noise vibration and harshness, power consumption is compared. The proposed starter is then tested in a crossover vehicle with four-cylinder engine. Simulation and experimental results proved superior engine autostart and key start performances due to lower inertia, higher torque, and power capability of the brushless motor, especially at higher speeds.