Design Con 2015

Lights for the life of the vehicle

-April 25, 2014

Normally, when people refer to the automotive industry making "parts that will last the life of the vehicle," it is the opening part of a joke similar to an "all you can eat for $1 restaurant." When you have parts that last the life of the vehicle, it is usually a vehicle with only one to three years of life.

This has now changed in a high profile and bold move by Ford. Their best-selling vehicle, and the top-selling vehicle in the US, is the Ford F-150 truck, and that truck now has full solid-state, passive-cooled LED headlights.

While many cars have added LEDs to the accent lights - e.g., turn signals, DRL (day time running lights), and interior lighting - they have not migrated to the main safety lighting of the vehicle, until now. The new LED modules in the Ford F-150 were under development with Ford and their LED partner OSRAM for many years.

The custom - and unique to Ford vehicles - color temperature of the light use a 1 x 4 LED module in a specially designed lens system. The lens system and focal point is adjustable at the point of manufacturing, to accommodate the ride height of different vehicles, so this technology can be permeated across multiple vehicle models.

One of the major challenges for the use of HBLEDs in the headlight system is the ability to:

  1. be a passive system for heat dissipation
  2. be a replaceable unit in the dealer and aftermarket support and
  3. be able to be usable for both high- and low-beam applications.

The passive heat dissipation system is a custom module that eliminates fans. The thermal module has heat sensors, as do the LEDs themselves, that feed back to the instrumentation cluster. The need for a passive system is to ensure that the module, with the exception of road hazard breakage, will work without failure for the over 10,000-hour life of the unit. This is well in excess of the MTBF of cooling fans and other mechanical systems.

The lights themselves had to be in a serviceable and replaceable module (see image). The EU has enacted regulation that mandates this level of serviceability. While it is not as yet required in North America, Ford chose to address this now, but supporting and stocking the dealer network with these modules is a major portion of the deployment into the new models.

The Ford F-150's LED headlamps - shown here with Ford lighting designer John Teodecki - use less energy and last five times longer than conventional headlamps. (Image Courtesy: Ford)

The module was designed as a high-beam/low-beam unit. This is a requirement to be able to share the polycarbonate outer cover and the decorative reflector unit. Unlike traditional lights, the reflector system does not actually contribute to the beam projection, it is directed by the over LED lens design. The whole light unit includes the driver electronics as a module.

The modules are coded so insurance companies and individuals can reuse units from "junked" cars as reclaimed parts. The instrument clusters communicate with the modules so they are replacement aware. At this time there are no third-party providers for these modules. Ford currently does not classify the subcomponents in the modules as replaceable.

The big deal is the supply chain update that was needed to provide a "life of the vehicle" part in a major high-use application. Training of the dealers and service network, education of the insurance carriers and claims adjusters, updating of the agreements with auto parts stores on not receiving the replacement parts for their stocking warehouses, and logistics for factory warehouses to have stocking capability for this long-lifecycle product as opposed to the standard five-year stocking system all had to be taken into account.

The design of the module also had to meet high-durability standards, due to being used in a "work targeted truck" as opposed to a typically garaged and commute-only passenger vehicle. The reality of this new design is that, for the first time, the parts will probably out-live the vehicle rather than the other way around.

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