A new type of swirl generator in a short straight port is developed to get induction swirl in the cylinder. The generator consists of several curvilinear diversion blades and is installed near to the inlet valve. Steady-flow rig tests show that this system is able to generate different strength of swirl in the cylinder when different type of generators is installed. By the control of the airflow rate in another port, variable swirl is achieved. Engine tests prove that variably induced swirl has a significant effect on diesel engine fuel consumption.