Here’s Mud on Yer Lens

It was still winter in many parts of the country when Ford announced its all-new ’15 Edge CUV and the ’16 Ford Explorer would join some Ford pickups in offering an automatic washing system for the vehicles’ exterior cameras.

Most who live in foul-weather regions probably shrugged and grumbled, “It’s about time.”

The irony is that those customers in crummy-weather markets, though surely thankful for the innovation, knew there was a need long before Ford and other automakers started to fill it. That we’re only now beginning to see wider adoption of camera-washing solutions demonstrates the industry’s occasionally odd and at times almost inverted cascade of technology adoption.

In the rush to fit rearview cameras, nobody seems to have worried much about how to keep them clean enough to actually be effective. A little more than 45% of vehicles sold in the U.S. in 2014 had a rearview camera as standard equipment, but of those models, few included some kind of automatic washing system or other technique to keep the camera’s lens clean.

Styling trends and the opportunity to integrate with other driver-assistance technologies started the stampede for rearview cameras, but the federal government cemented the deal when the Department of Transportation last year finalized a regulation requiring all vehicles weighing less than 10,000 lbs. (4,540 kg) to be fitted with a rearview camera. Phase-in of the rule begins by requiring at least 10% of an automaker’s fleet be compliant between May 1, 2016 and May 1, 2017; 40% must comply between then and May 1, 2018, after which every light vehicle an automaker builds will be required to have a rearview camera.

Front cameras also are an increasing part of the driver-assistance equation, too. But except for a few truck and SUV applications that call for a grille-mounted exterior camera – mostly to facilitate knotty offroad maneuvers – front cameras are designed to look down the road well in advance of vehicle travel, says Andrew Whydell, director of product planning-global electronics for safety-components supplier TRW Automotive.

That means forward-looking cameras designed for high-level driver-assist (and eventual autonomous-driving) functions are required to be mounted behind the windshield and within the area that’s cleaned by the wipers, Whydell says. The front camera thus is protected altogether from exterior conditions but also is virtually guaranteed a consistent clean field of vision by the existing windshield-cleaning system and the driver’s own desire for unobstructed view.

Look Back in Clarity

So the real cleaning problem centers on rearview cameras. Jennifer Shaw, Ford’s driver-assistance electronics supervisor and one of the engineers for the automaker’s new rear-camera-cleaning systems, says that because of the DOT requirements for rear-camera field-of-vision, they typically can’t be high-mounted – or inside the rear glass area.

“It’s about giving the driver the best field of view possible,” says Shaw, who explains that the regulation stipulates rear cameras must be able to see cones strategically placed low on the ground, both below and outside the rear bumper area. After all, the DOT sees rear cameras first and foremost as prevention against humans being run over in reversing accidents. She adds that although contemporary cameras can provide as much as a 180-degree field of view, the need to place the camera low and as far rearward as possible means “packaging is always a challenge.”

That is to say, the camera needs to stick out. And whatever sticks out is likely to get wet, dirty or caked with ice and snow.

You can wipe off the camera yourself – but typically you don't realize the camera is obscured until after you’ve belted in and engaged reverse, only to realize the camera’s obscured. Avoid that hassle with Ford’s new system, which like a mini-power washer sprays the camera lens with a high-frequency oscillating stream of fluid delivered from the windshield-washer reservoir. The system, developed with Bowles Fluidics, gives the rear camera a wash any time the driver elects to clean the windshield or rear window.

Volkswagen’s elegant solution for CC sedan: Shelter rearview camera behind car’s badge, which flips up when camera is needed.

Ford’s not the first and only mainstream brand to facilitate rear-camera hygiene – among others, Nissan has had a washer system for the Altima midsize sedan since 2013 and Volkswagen’s CC sedan cleverly protects the camera behind a flip-up trunklid badge. 

A camera-washing system can be comparatively inexpensive, particularly if the vehicle already has a rear-window washing function, as do almost all CUVs and SUVs, for example. Camera washing setups usually can be added to existing models during midcycle refreshes with a minimum of engineering disruption, Shaw says.

After seeing the clear need for rearview camera cleaning and some illuminating early experience with how inclement weather can affect the more mission-critical external sensors for advanced driver-assistance systems, Shaw and TRW’s Whydell reckon you’ll see distinct cleaning strategies developed – and perhaps mandated – before semi-autonomous or fully autonomous functions are approved for widespread production-car use.

Let Us Spray

Squirt-cleaning seems almost an incongruously low-tech companion for sophisticated autonomous-driving components, but absent a groundbreaking development, it might be the most effective and cost-efficient answer.

For example, the lens covers for all of Ford’s rearview cameras already have a special hydrophobic coating designed to repel a certain amount of water and dirt. Toyota, Porsche and others sporadically have used hydrophobic treatment for windshields and other greenhouse glass. “We already are using lens coatings – the problem is, they’re not working very well,” admits Shaw.

Bob Newton, TRW’s global engineering lead-DAS camera optics/mechanical, agrees that while hydrophobic or hydrophilic (think more of a sheeting-action repellent) coatings for camera lenses are reasonably effective, they’re not good enough. Newton says an additional concern is the longevity required for typical automotive lifecycles: “They tend to not be long-term coatings.”

Ford’s Shaw says there’s potential for advanced design techniques to keep cameras cleaner. “If we pay (increased) attention to the aerodynamics of the (camera) placement,” there may be opportunities to ensure some amount of spray and road grime simply don’t find their way to the camera. Placing the lens under the trunk release or other sheet metal creases helps, she says, but typically doesn’t guarantee cleanliness, particularly in winter.

TRW’s Whydell sees the possibility for wider adoption of “movable” sensors such as Volkswagen’s solution with the CC’s rearview camera, which flips into exposed position only when needed. For advanced sensors for autonomous driving, he says movable arrangement might enable the sensor to somehow clean itself – and whatever the cleaning system, he envisions sensors programmed to realize they’re too dirty to function and “request a clean.”

For rearview cameras, more manufacturers may bake in “hidden” arrangements, Volkswagen CC-like, for all-new models with entirely new styling. But for now, camera washing (and eventually, sensor washing) seems by almost any metric the best available solution. “I would love to put a washer on all our rear cameras – we like that solution at Ford,” says Shaw.

“It’s a well-proven technology,” TRW’s Whydell concurs.