7. Current status and outlook for supercharging

Until now, turbo-supercharging has been the only way to supercharge engines. It has gradually spread to the field of large and medium-displacement direct-injection diesel engines: naval propulsion, industrial engines, rail traction, road transport (trucks), etc. In the automotive sector, it applies to both indirect-injection and direct-injection diesel engines. In the automotive sector, it applies to both indirect-injection and spark-ignition diesel engines, but its application remains limited to "top-of-the-range" models.

This limitation is based on economic reasons (the extra cost of supercharging), but also on technical reasons for small-displacement engines in particular, where the turbocharger's "response time" is a handicap for vehicle acceleration performance. The possible future widespread use of turbocharging depends on these two constraints being overcome....