The Achilles heel of turbochargers has always been the time between pressing your foot to the gas pedal and waiting for the engine to respond with the desired power. This lapse in engine response, commonly termed turbo lag, is what has hindered turbochargers from delivering optimal performance. The aim of a turbocharger is to provide more power, better efficiency and less lag in power delivery. Engine efficiency is becoming more important than ever before, leading to the development of smaller engines. However, the power requirements are not decreasing which means the loss in engine displacement from small designs must be picked up with alternative technologies, such as turbochargers, which can help improve power delivery and fuel economy.
Electric turbochargers (e-turbos) provide a solution to eliminating turbo lag while adding additional performance benefits. This allows for larger turbocharger designs which can provide larger power and efficiency gains, stay cooler over longer periods of use, and drastically improve engine responsiveness. Garrett Motion are developing e-turbos for mass market passenger vehicles set for launch in 2021, with a claimed fuel efficiency improvement of up to 10%. When used on diesel engines, this e-turbo could be up to a 20% reduction in NOx emissions. In most cases, fuel efficiency will be improved by about 2 – 4%. Other manufacturers such as Mitsubishi and BorgWarner are already developing their own electric turbos and are expected to have announcements in the near future matching the trend in e-turbo development.