ABSTRACT
Automakers are under immense pressure today to improve fuel economy and also reduce vehicle emissions. However, to retain profitability, automakers must also ensure that the vehicles being manufactured are affordable, profitable, and desirable to prospective customers. It has been well established that full hybrid vehicle (HV) technology is the most cost effective way to improve fuel economy, reduce emissions, and still maintain customer demands of performance, comfort, and cost. The most implementationamenable and perhaps the lowest cost hybrid technology for meeting these goals is sometimes referred to as a “soft hybrid.” A soft hybrid utilizes a small 6-10 kW integrated starter generator (ISG), which is sometimes also referred to as a combined starter/alternator (CSA) or as an integrated starter-alternator (ISA). A small ISG, or what has been called a belt-ISG, can be mounted on the front of the engine and utilizes the FEAD (front engine accessory drive) belt to start the engine. An ISG can also be integrated into the transmission bell housing and coupled to the rear of the engine crankshaft, in what is known as a crankshaft-ISG. The operational strategy resulting from shutting the engine “off” at stoplights and other conditions when the engine is not needed to provide mobility is referred to as “idle-stop”. Because the ISG is typically rated from 3 to 8 times the power of today’s engine starter motor, the engine can be re-started in a much shorter time than in a vehicle equipped with only a conventional flywheel mounted starter. The impact is starting performance that is brisk, silent, and transparent to the customer.
