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Is the braking system spec’ing process more complex than it needs to be?

EAST LIBERTY, Ohio - Traditionally, component suppliers have treated the braking system as a complex puzzle for which there are a large number of possible solutions. Between the foundation brakes, lin...





EAST LIBERTY, Ohio – Traditionally, component suppliers have treated the braking system as a complex puzzle for which there are a large number of possible solutions. Between the foundation brakes, linings, drums, air system and controls, nearly 500 combinations of suppliers and products are possible.

Meritor WABCO is banking on a hunch that fleet equipment buyers would prefer a simpler approach as it moves on an evolutionary path towards creating a “complete braking system.”

Such a system would allow suppliers and vehicle manufacturers to emphasize not only how brake system components fit together but take the science to the next level to determine how brake system components can best work together for the truck and trailer operator.

“The business model so far has been a broad base of suppliers.

We are the only supplier who brings to the marketplace the complete package,” Dennis Sandberg, president and general manager of Meritor WABCO Vehicle Control Systems told truck journalists at a recent meeting to update the industry on the company’s products and future market direction.

Meritor WABCO is a joint venture of ArvinMeritor and WABCO Automotive Products.

Meritor WABCO contends that while the recent launches of products such as reduced-maintenance brakes and wheelends, the latest air disc brake technology, advanced communication capabilities, and long-life lining mixes have brought direct savings and improved performance for truck fleets, the individual component improvements just scratch the surface when compared to what a complete stopping system would be able to provide.

In addition to improving performance by being able to use matched components that are geared towards working better as a system, other benefits of a complete braking system cited by Meritor WABCO officials included:

Simplified troubleshooting: If a problem does occur within the braking system, the end user has only one company to call to get the issue resolved.

Simplified warranty administration: Fleet managers would no longer have to recoup warranty expenses from several sources. The sole supplier would warrant all components within the complete braking system.

Lighter weight: Meritor WABCO feels that by being able to have control of the design process for the entire braking system it would be better able to take advantage of the checks and balances necessary to reduce system weight.

The case for moving to a complete braking system also counts improved safety as a benefit, a key point considering the U.S. government plans to reduce commercial vehicle-related casualties by 50 per cent from the current figure and wants a 30 per cent reduction in heavy truck stopping distance, which is currently set at 355 feet. (The Canadian government is also looking at further reducing truck casualties.)

Several of the Meritor WABCO officials Truck News spoke to felt confident they could significantly improve stopping distance by integrating technologies such as air disc brakes, ABS with Roll Stability Control and EBS.

Paul Johnston, business unit director, North American foundation brakes, says that even by tinkering with current standard drum brake technology, the stopping distance can be improved to around 250 feet.

By moving to high-output cam brakes stopping distance can be cut further to 220 feet and a move to air disc brakes may see stopping distances reduced to 200 feet.

Expect EBS to gain a foothold in the market place as well, although likely not for another four to five years.

“Why hasn’t EBS been successful so far? Most fleets don’t want to pay a premium for current EBS and I emphasize current EBS,” says Rick Romer, director of electronic products.

He adds that he expects new rules from the U.S. government on EBS by 2007 that may make the EBS system more economical by allowing more of the backup system to be electronically controlled.

Meritor WABCO also used the opportunity to announce several new braking products for the market.

Of particular interest is its new Roll Stability Control (RSC) and Roll Stability Support (RSS systems), which have been designed for linehaul tractor/trailer combinations to reduce the likelihood of a rollover situation.

Demonstrations of the product in action on a test track were eye-openers in terms of how quickly rollovers can occur and how adept the new technology can be in preventing them from happening.

“We really view this as a breakthrough technology for the industry,” Sandberg says.

Not long ago, we viewed this as something that would happen when EBS came along. But then we thought the industry is not going to wait that long.”

The RSC tractor system is available now through OEMs. The trailer system, RSS, will be available through trailer OEMs by mid year.

“All the things initially planned for EBS the market now wants available with ABS,” Romer exclaimed in further explaining the company’s move to offer such products at this point.

The RSC system focuses on a vehicle’s center of gravity and the lateral acceleration limit or rollover threshold.

When critical lateral acceleration thresholds are exceeded, RSC intervenes to regulate the vehicle’s deceleration functions.

That intervention occurs in three forms – engine, retarder and brake control.

An accelerometer mounted directly to the ABS electronic control unit monitors the vehicle’s lateral acceleration.

RSC constantly monitors driving conditions and intervenes if critical lateral acceleration is detected.

The system provides control of engine and retarder torque as well as automatically activates the drive axle and trailer brakes.

Praxair is one of the fleets that has already bought into the system.

The technology is integrated in the trailer EBS requiring no additional hardware.

Similar to the tractor’s RSC system, the RSS focuses on lateral acceleration and wheel speed, monitoring the critical acceleration limit.

If this limit is exceeded, the trailer brakes are automatically applied helping to reduce the vehicle’s speed.

The company also announced what it considers “significant engineering enhancements” to its Q Plus drum brakes that it says make for improved stopping performance for heavy-duty commercial vehicles.

According to the company, the Q Plus brake offering consists of larger 16.5″ x 5″ brakes on the front steering axle coupled with standard size 16.5″ x 7″ brakes on the rear axles.

Both brakes utilize proprietary Meritor MA210 lining material, which offers greater stopping power and significantly improves lining drum wear, as well as parking capability, compared to other materials.

According to company engineers, testing performed to Federal Motor Vehicle Safety Standard (FMVSS-121) procedures show the enhanced brakes deliver significantly more torque, resulting in greatly reduced stopping distances when compared to similar vehicles equipped with conventional front brakes.


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