More stringent regulations have led many original equipment manufacturers (OEMs) to implement gasoline direct injection (GDI) engines, which provide improved fuel economy, reduce emissions, and increase power. A leading OEM found they had pressure pulsations in the low-pressure fuel line, upstream of the single-piston high-pressure pump. Under certain driving conditions these pulsations created noise, vibration, and harshness (NVH) issues for the customer and fatigue wear issues in the low-pressure fuel system. The issues—identiﬁed 10 months prior to the planned vehicle launch—could lead to signiﬁcant schedule delays. The OEM tried 23 potential solutions that did not work, and the product launch was in jeopardy.
The Lee engineering team met with the OEM to discuss the problem, the system layout, mounting options, and the high-level performance requirements. The OEM was looking for a component that would dampen pressure spikes returning to the tank, provide a thermal relief function, have a negligible effect on free ﬂow to the high-pressure pump, and ﬁt within their system.
|1 – FUEL TANK
2 – LOW-PRESSURE PUMP
3 – LEE FUEL LINE CHECK VALVE
4 – HIGH-PRESSURE PUMP
|5 – INJECTION NOZZLE
6 – GDI ENGINE
7 – SIGNIFICANT PRESSURE PULSATIONS AND NVH
8 – REDUCED PRESSURE PULSATIONS AND NVH
In less than one week, Lee engineers designed, built, and delivered a unique potential solution to the OEM. Testing conﬁrmed that the fuel line check valve solved their performance problems. The new solution reduced the pressure pulsations by up to 90%, ﬁt within their existing fuel line, and met all other performance requirements. Over the next six months, The Lee Company designed and fabricated a completely new production line, supplied Production Part Approval Process (PPAP) parts, and started production. The Lee Company was able to quickly transition from initial design concept, through validation, and into production; this helped the OEM launch the vehicle on schedule and safeguard their reputation.
The solution that The Lee Company provided for dampening the pressure spikes is a multi-function valve that combines the performance of a check valve, a pressure dampening restrictor, and a thermal relief function. It is easy to install and doesn’t require customized mounting equipment or add potential external leak paths within the fuel system. This innovative valve can be added to the fuel system to dampen residual pressure pulsations discharged from the high-pressure pump and it virtually eliminates NVH and fatigue wear on the low-pressure pump.
Since this initial application, The Lee Company’s fuel line check valve has been used by multiple OEMs across the globe. Designs are available for a variety of standard fuel hose materials and sizes. This valve is a reliable solution to any pressure dampening application. There are over 35 million currently in use.
The fuel line check valve continues The Lee Company’s mission to design and build state-of-the-art products that exceed customers’ expectations for utility, performance, and quality. The Lee Company acts as an engineering partner and problem solver for customers. The ultimate goal is zero defects and satisﬁed customers