system. When the cylinders exhaust into a la receiver the outflow of gas is quicker because the large gas impulse at the commencement of the exhaust period is levelled out in the gas receiver and the outflow of gas will not be retarded, as in the case of impulse turbocharging where a pressure peak is built up in the narrow exhaust pipe before the turbocharge. The opening of the exhaust valve can be delayed about 15°, thereby lengthening the expansion stroke and improving the efficiency and reducing the fuel consumption. The energy before the turbine is less than for impulse turbocharging but as the pressure and temperature before the turbine is nearly constant the turbine can be adapted to run at peak efficiency and the blower can supply sufficient air above 50 per cent of engine load. The scavenging air pressure is increased and the compression pressure somewhat decreased compared with impulse turbocharging