of intake valve 74 moreover and in accordance with the present invention injection of the vaporized air fuel mixture introduced through the guide body 78 of intake valve assembly 80 is adapted to occur in response to the opening of the control relief valve 46 which in turn is adapted to occur during the opening of intake valve 74 still further in accordance with the present invention the resultant high velocity high pressure flow or injection of the air fuel mixture through the intake valve guide body 78 is adapted to induce an increased flow of intake air through intake valve opening 86 and into the engine cylinder cavity 84 moreover and as shown in fig1 the intake port 81 of air manifold 82 is located and positioned relative to the engine intake valve 74 in a manner whereby air is drawn into the engine at a point below the nozzles 48 and the vaporized air fuel mixture traveling through the valve guide body or sleeve 78 and nozzles 48 and is mixed with the intake air at a point adjacent and directly above the cylinder valve opening 86 stated another way the intake air is fed into the space defined between the distal end of the guide 78 where the air mixes with the air fuel mixture being delivered through nozzles 48 and then directly therefrom through opening 86 in accordance with the present invention mixing the intake air and fuel vapor at the opening 86 increases the volumetric efficiency of the engine by minimizing the distortion of the intake air.