Locomotive Engine Starting
Large locomotive diesel engine starting can be assisted with ultracapacitors to reduce the load on the power source (generally a group of large lead acid batteries). When starting a locomotive engine, the starter battery is discharged due to the load of the starter, which spins the main engine crankshaft to the proper starting speed. After a few working strokes of the crankshaft the engine starts (assuming proper fuel, fuel mixture, compression and ignition). While starting the locomotive engine, the starting battery system has to power up several other engine related accessories, such as hydraulic pumps, and heater in some instances. All of these additional loads further reduce the battery system’s capacity to crank the engine. In these cases, a properly sized group of ultracapacitors, can be connected in parallel with the battery system to provide "assisted power” to the system that will reduce battery drain and stabilize the battery system voltage during starting events. In this configuration the state of charge of the battery system does not affect the locomotive engine starting characteristics.