Body-in-White Re-engineering for Fuel Pump Access

Digital serviceability support from USE* Automotive promotes and enculturates a design for serviceability mindset into product development activities. USE* classify these services as SERP (Service Evaluation and Repair Process), reflecting both the competent expertise that we provide to support this function and our out of the box process toolset that we can deploy and adapt to any of our customers’ product development PLM systems.

In this case study, early engagement with product development enabled USE* to drive a cost-saving design change to floor pan architecture.

The Challenge

The initial proposal for the floor pan design for the future common platform for a range of our client’s vehicles included an access hole in the floor pan to allow manufacturing access to the in-tank fuel pump, fuel filter and fuel sender assembly to make wiring harness connections. However, it quickly became apparent that the hole was not of sufficient size to allow tooling access and the subsequent removal and re-fitting of the in-tank module in the event of a failure in service.

The initial proposal would have necessitated the removal of the fuel tank to access the in-tank module for removal. In the case of vehicles with a complex drive train, this requires extensive disassembly of the driveline and exhaust systems, with the potential result of a significant warranty labour cost in the event of a module failure.

The challenge for SERP engineers engaged in the layout creation phase of vehicle design was to justify the need for an increase in the size of the aperture in the floor pan, to off-set the resulting impact on structural integrity, NVH and cabin sealing. There was an additional challenge of working with immature CAD data and a rapidly developing package environment.

The Solution

The first objective was to create digital labour times for the removal of the fuel tank in order to gain access to the fuel pump module. This required extensive collaboration with product designers due to the immaturity of the CAD data at such an early stage of the vehicle programme. Service repair operation labour times require accurate information regarding fixing strategies and wiring harness and electrical connector information, all of which is not generally available until much later in the vehicle development timeline. Once this information had been gathered and the digital labour times created, engineering buy-in was required to verify that the digital labour times accurately represented the current design intent. It was then necessary to generate digital labour times for the in-tank module service repair operations based on a sufficiently sized floor aperture that allowed removal with the fuel tank in place.

This process required the verification of special service tool access. It also needed the creation of service CAD geometry to represent the withdrawal path of the in-tank module and the technician-hand access required to remove and replace it.

In order to justify a change to the floor design, a projected warranty cost saving had to be assessed. This was achieved by analysing warranty information for existing vehicles using a similar in-tank module strategy. The recorded number of failures could then be used alongside the projected digital labour time saving to derive a potential cost saving figure.

Once senior management had approved the change to the floor pan, it was then necessary for SERP engineers to support the product designers with up to date and accurate service CAD geometry as described above, to ensure that the final design intent met all service requirements.

Its Benefits

Due to the early engagement with product development, it was possible to integrate the change to the floor pan design into the programme. This would have been significantly harder to achieve at any later stage in the development of the programme. An additional benefit of the early engagement was that the change to the floor pan could be designed in a minimal cost to the programme. This was because the design change could be made before costly CAE and manufacturing verification activities had begun.

Our Achievements

Early SERP engagement into the lead vehicle programme for the platform means that this service feature has been designed into all of our client’s future programmes.

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