Program: Rear Wiper System Engineering
Vehicle Platform: Battery Electric SUV
Program Phase: Concept through Mid-DVPI
Overview
This program involved engineering a rear wiper system for a battery electric SUV with a drop-glass rear window architecture. Because the rear glass retracts into the body rather than housing a conventional tailgate surface, standard rear wiper mounting solutions could not be used.
Goken supported the full development of a new packaging solution that integrated the entire rear wiper system within the rear fascia. This rear wiper system engineering engagement ran from initial concept through mid-DVPI validation, covering packaging, performance, and cost requirements.
Engineering Challenge
Three compounding constraints defined the scope of this program:
Packaging: No Conventional Mounting Option
Traditional rear wipers mount to the tailgate or rear spoiler. On this platform, neither was available. The drop-glass rear window design eliminated tailgate mounting, and the split spoiler configuration, with exposed aerodynamic openings, ruled out spoiler-mounted solutions. The entire system had to fit within the rear fascia trough area below the glass line. There was no industry benchmark for this configuration.
Cost: Hard Targets From Day One
The rear wiper was a value-add feature at risk of program deletion if cost targets were not met. Cost engineering was not a downstream filter. It was embedded into every design decision from the start.
Integration: Multiple Interfacing Systems
The rear wiper system interfaced with the electrical architecture, water flow and drainage, the heater coil, the tailgate, and rear fascia structure. Each had its own design teams and constraints. Spatial envelopes had to be defined early and communicated precisely to prevent late-program conflicts.
Scope and Approach
System Architecture and Kinematic Analysis
Following a structured automotive product development process, the team began with a wiper system architecture that defined the required wipe angle, sweep coverage area, and full motion envelope. KTI-based kinematic simulation mapped the position of all moving elements across their operating range, identifying minimum and maximum spatial boundaries, potential interference zones, and required clearances for thermal expansion, vibration, and tolerance stack-up.
Advanced Rear Fascia Packaging
With the validated kinematic model, detailed rear wiper packaging studies resolved the wiper system's full motion envelope against the available volume inside the rear fascia trough. Wall thicknesses, drainage channels, electrical routing, fastener zones, and thermal management components were all accounted for.
Cross-Functional Envelope Coordination
A key program deliverable was the formal geometric envelope definition issued to all interfacing engineering groups. This spatial claim, defining what volume the wiper system required, allowed rear fascia, tailgate, electrical, drainage, and heater coil teams to design around the wiper system accurately and in parallel.
Off-the-Shelf Sourcing Strategy
To meet cost targets without creating new tooling or qualification cycles, we pursued a maximum off-the-shelf sourcing strategy. Wiper blade, partial frame, and motor were all selected from existing supplier catalog offerings. Each was validated against the specific thermal, vibration, and moisture requirements of the rear fascia installation before sourcing was confirmed.
Outcome
The program delivered a validated, production-ready rear wiper system fully compatible with the drop-glass EV platform. Key results:
- System passed DVPI validation with positive results and was confirmed suitable for production integration.
- Significant cost reduction achieved relative to early concept estimates, driven by disciplined off-the-shelf sourcing throughout development.
- Rear wiper feature retained on the production vehicle. The feature had been at genuine risk of deletion, and it was retained without requiring redesign of the rear fascia or tailgate.
- Scope extended post-DVP into supplier coordination, providing continuity from engineering development into production launch preparation.
Capabilities Demonstrated
- Wiper kinematics simulation and rear fascia packaging analysis
- Cost engineering and should-cost analysis embedded in design
- Cross-functional geometric envelope coordination across interfacing EV exterior systems
- Validation and verification through DVPI
- Program continuity through timeline disruptions and scope expansion, delivered through Goken's mobility industry engineering practice
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