that can be closed by a butterfly valve 44 within the passage 39 a number of exhaust passages 45 extend inwardly from the periphery of the rotor 36 and these carry exhaust gases away the pressure in the hollow center port 38 causes combustion gas to flow along each radial passage 39 to cause clockwise rotation of the rotor 36 due to gas u2014 force exerted on each flap 43 during clockwise rotation spent gas at the other side of each flap 43 escapes via the exhaust passages 45 when the flap encounters the ramped surface 41 of the next buffer 40 it closes enabling rotation of the rotor 36 to continue the flaps might be spring biased to re open the rotor 36 is connected to the drive pulley 22 the oil pressure chamber 28 acts as a pressure buffer device serving to alleviate excessive pressure this device prevents explosive failure of the combustion chamber 11 it further serves to stabilise pressure within the combustion chamber for delivery to the turbine 21 it also serves as a standby hydraulic system for powering ancillary hydraulic equipment such as door closing devices steering wheel retractors seat belts hydraulic suspension and the like more importantly when the internal combustion engine of the preferred embodiment is installed in a motor vehicle the vehicle may come to a standstill without omission of exhaust gas for a short period of time before moving off at traffic lights for.