Computer simulation of air injection to the inlet manifold on turbocharged engines

The drive to reduce engine emissions has placed an emphasis upon
turbocharging especially with the trend of engine downsizing (1, 2). Turbocharged vehicles
exhibit a weak point of poor drivability under transient running conditions. Reduced air flow
in the combustion chamber while fuel is injected causes inadequate air fuel ratio (i.e. rich
mixture). The result is an increased formation of emissions such as CO, NOx which contribute
to environmental pollution. Air injection increases the air flow during the transient phase
reducing the harmful emissions. Experimental work has shown that injecting air into the
manifold greatly improves the transient response of the turbocharger (3, 4). This work has
shown that air injection has a large effect upon improving the transient response. This paper
shows the effects of air injection using computer simulations and the improvement that the air
injection has on the response of the turbocharger within the engine system.