Engine boosting is the process of increasing the amount of air in the engine that is available for combustion, resulting in a “boost” in engine power. This is accomplished by a supercharger or turbocharger, which force additional air into the engine using a blower.
Supercharger – the blower is connected to the engine crankshaft and uses engine power to force air into the engine. The supercharger has a very fast response time but adds an extra load to the engine and is optimized for one speed range:
Turbo Charger – the exhaust gases from the engine are directed to and drive the blower. The exhaust gases are “free” power to drive the blower but there can be a lag in response time and less boost at lower engine speeds due to less exhaust:
Both the supercharger and turbocharger have limitations that could be improved with an adjustable speed drive. For the turbocharger, placing Orbital Traction’s Controlled Velocity Accessory Drive (CVAD) between the turbine and the compressor would allow the compressor to reach operating speed at lower exhaust gas flow rates and reduce power lag. With the supercharger, placing the CVAD between the turbine and the drive pulley would result in a wider speed range of operation for the super charger and increased use of engine power.
The benefits of engine boosting with a CVAD are: