Trailer Talk

Intellipark Takes the Sting Out of Parking Brake Valves

Blog commentary by Tom Berg, Senior Contributing Editor

October 16, 2017

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Familiar red and yellow valves are clumsy to operate and sometimes allow vehicle runaways. Photos: Bendix Commercial Vehicle Systems. 
Familiar red and yellow valves are clumsy to operate and sometimes allow vehicle runaways. Photos: Bendix Commercial Vehicle Systems.

As much as I enjoy driving tractor-trailers, one thing that has irked me for many years is the parking brake valves on the dashboard. The two push-pull valves -- the yellow one for tractor brakes and the red one for trailer brakes – are awkward to release because they must be pushed hard and held before brakes are released. And when pulled to apply the brakes, they pop out, sometimes stinging one’s fingers – my fingers, anyway, which I suppose makes me a wimp.

Those valves might be low on professional drivers’ complaint lists, but I doubt that I’m the only one who finds them clumsy to use. And there’s a better way. European heavy and medium trucks use a handy joystick-like control that applies the parking brakes when swung one way and releases them when swung another. A collar that’s pulled up by one’s index and middle fingers unlocks the stick for movement either way. It’s simple and very easy to use. Paccar employs this on the medium-duty cabovers sold by its Kenworth and Peterbilt divisions.

That the joystick parking-brake device is used here tells me that the system is not illegal in the U.S. Why, then, does every American-built truck have the two push-pull valves (or one yellow valve if the truck is not made to pull a trailer)? Because it’s an industry standard, promulgated by the Society of Automotive Engineers in the 1950s, explains Fred Andersky, director, customer solutions for Bendix, which is among the manufacturers of air-brake equipment. The shape, color, and lettering on the valves is in the standard, but it's not in a federal regulation.

Bendix sees a more serious problem with the valves: They sometimes do not apply the parking brakes, and vehicles can roll away. That’s embarrassing and has led to collisions and injuries – more than we normally hear about, Andersky says. So Bendix engineers have come up with an alternative: the Intellipark electronic system. It uses a pair of spring-loaded blade-type switches that are wired to servos inside the dash. Those are connected to air valves that set or release the brakes.

Electronic interlocks automatically apply the brakes when sensors signal that the driver has left his seat or opened the door before applying the brakes. That’s the “intel” part of the device, and the one that would prevent vehicle rollaways. I think it’s also smartly designed because the switches — large versions of power-window switches, I’d call them — are easy to manipulate.

Bendix installed an Intellipark in a mock truck cab for display at the recent North American Commercial Vehicle Show. I climbed in and tried it. The switches take very little pressure to operate, and lights indicate whether the brakes are applying or releasing. Switches are labeled to mimic the current diamond-shaped yellow and red valve handles, complete with wording, so there shouldn’t be any confusion.

Bendix's Intellipark has two blade type switches wired to servos that operate the air valves behind the dash. Sensors on the seat and door tell the system to apply the brakes if the driver doesn't before leaving the cab. 
Bendix's Intellipark has two blade type switches wired to servos that operate the air valves behind the dash. Sensors on the seat and door tell the system to apply the brakes if the driver doesn't before leaving the cab.

In its press release, Bendix said Intellipark provides data – something else not available from an air switch – to help indicate if a rollaway occurred or almost happened. That data can be transmitted via telematics to fleet offices, where managers can react appropriately. (I can see it now: A manager calls a driver and says, “Say, Larry, do you know where your truck rolled to?” Or, “Where are you working tomorrow?”)

Additional features include Park-at-Speed, which brings a moving vehicle to a controlled stop if the parking brake is activated. Trailer Air Warning indicates the status of the trailer’s air supply through a light or other indicator on the dash. Trailer Auto-Park Release disengages the trailer parking brakes automatically when an operator inadvertently attempts to drive away with it on – helping to reduce the chance of trailer tire fires and wheel-end damage.

“Intellipark will also be a key part of the foundation for the future,” Andersky said. “It will serve as a component delivering even more parking brake control for automated or even autonomous vehicles.” That makes it rather topical.

It all sounds good, although yes, it introduces more complexity to a vehicle. Bendix will find out how Intellipark stands up to everyday use through fleet testing that starts early next year. Thus it’ll be a while before it’s available on new trucks. I’ll look forward to that.

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Author Bio

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Tom Berg

Senior Contributing Editor

Journalist since 1965, truck writer and editor since 1978. CDL-qualified; conducts road tests on new heavy-, medium- and light-duty tractors and trucks. Specializes in vocational and hybrid vehicles.

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