The present invention generally relates to an impeller for a fuel pump for an automotive vehicle.
Regenerative fuel pumps having a ring impeller are well known technology. These type of fuel pumps are relatively cheap to manufacture, robust and efficient, particularly in lower flow high pressure applications. However, this type of fuel pump has disadvantages when used for higher flow applications. The structure of the ring impeller forms two flow chambers. One is an inlet side flow chamber and the other is an outlet side flow chamber. First, fuel flows into the inlet side flow chamber and across the impeller to an outlet hole. Secondly, fuel flows across the impeller near the inlet to the outlet side flow chamber and exhausts into the outlet hole. When the fuel flows across the impeller, there is a limited flow path so the velocity of the flow is increased. The increase in velocity of the fuel flowing across the impeller results in flow turbulence and pressure losses. The increase in turbulence increases the production of vapor in the fuel flow, which decreases the efficiency of the fuel pump. Additionally, if the fuel is hot, vaporization of the fuel occurs even more readily, thereby multiplying the problem of vapor production.
Traditional fuel pumps have tried to alleviate these problems by focusing on the fuel inlet areas of the fuel pump. These improvements do not address the issue of fuel vaporization in high flow automotive applications. Therefore, there is a need for an improved fuel pump impeller which will reduce the amount of fuel vaporization in high pressure, high flow applications.