Electric supercharger
Encyclopedia
An electric supercharger is a specific type of supercharger
that uses an electrically powered forced-air system that contains an electric motor
to drive an axial flow fan to pressurize the intake air while it rids the inlet and filter box of most restriction. It is designed to operate only at full throttle, since this is the only time when the throttle butterfly-valve is fully open and out of the way of the engine's intake. By pressurizing the air available to the engine intake system, the air becomes more dense, and is matched with more fuel, producing the increased horsepower to the wheels. In simpler terms, the typical electric supercharger will not increase the horsepower of an automobile due to the inability of a small fan to produce positive pressure at the necessary CFM.
However, belt driven mechanical superchargers consume some of the power produced by engine in particular at low revolutions (see Supercharging versus turbocharging supercharger
), while electric superchargers are decoupled from an engine via an oversized energy storage (e.g. several electric accumulators in series). This results in different "somewhat raw" boost supplied during low revolution regime of the engine.
The losses are in general higher than direct kinematic linkage of intake air compressor to engine crankshaft.
Special consideration need be given to the coaxial electric motor operating in proximity of a hot turbine at very high revolutions (up to 10000 rpm).
Supercharger
A supercharger is an air compressor used for forced induction of an internal combustion engine.The greater mass flow-rate provides more oxygen to support combustion than would be available in a naturally aspirated engine, which allows more fuel to be burned and more work to be done per cycle,...
that uses an electrically powered forced-air system that contains an electric motor
Electric motor
An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...
to drive an axial flow fan to pressurize the intake air while it rids the inlet and filter box of most restriction. It is designed to operate only at full throttle, since this is the only time when the throttle butterfly-valve is fully open and out of the way of the engine's intake. By pressurizing the air available to the engine intake system, the air becomes more dense, and is matched with more fuel, producing the increased horsepower to the wheels. In simpler terms, the typical electric supercharger will not increase the horsepower of an automobile due to the inability of a small fan to produce positive pressure at the necessary CFM.
Electric superchargers vs. Belt Driven
In general, while electric superchargers are less expensive than belt-driven superchargers, the horsepower boost that they provide is also significantly less.However, belt driven mechanical superchargers consume some of the power produced by engine in particular at low revolutions (see Supercharging versus turbocharging supercharger
Supercharger
A supercharger is an air compressor used for forced induction of an internal combustion engine.The greater mass flow-rate provides more oxygen to support combustion than would be available in a naturally aspirated engine, which allows more fuel to be burned and more work to be done per cycle,...
), while electric superchargers are decoupled from an engine via an oversized energy storage (e.g. several electric accumulators in series). This results in different "somewhat raw" boost supplied during low revolution regime of the engine.
Power supply for electric superchargers
An electric supercharger, if supplied by series of common stock electric accumulators, runs independent of the engine to which it provides its boost. However, electrical energy consumed is often higher (in the range of 100 A e.g. Power of 10 kW = 12V * 833 A) than what a production-line generator (e.g. alternator) of the engine can supply. Larger alternators are therefore fitted to recharge accumulators (often reconnected from serial to parallel circuit) during the engine run without the boost.Efficiency
The efficiency of electric supercharges is curbed by several energy conversion losses (alternator for charging), damp energy while charging the accumulators and compressor providing boost.The losses are in general higher than direct kinematic linkage of intake air compressor to engine crankshaft.
Electric assisted turbochargers
Electric assisted turbochargers are turbochargers employing a coaxial electric motor to overcome the time lag of the exhaust gas driven turbine. The electric motor supports the exhaust gas driven turbine at low-end revolutions to compress enough air into engine's intake, while it can be configured as an alternator to extract energy from the exhaust gas driven turbine at high-end revs, which would otherwise need be bypassed via wastegate and eventually replacing the current mechanically driven alternator .Special consideration need be given to the coaxial electric motor operating in proximity of a hot turbine at very high revolutions (up to 10000 rpm).