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Electronic evolution

Engineers are usually dreaming up ways to protect sensors and their connectors from the forces of vibration. But near the end of a Technology and Maintenance Council presentation about vehicle electro...


The electronic evolution has paved the way for stability control systems that continuously read data such as steering wheel position and G-forces.
The electronic evolution has paved the way for stability control systems that continuously read data such as steering wheel position and G-forces.

Engineers are usually dreaming up ways to protect sensors and their connectors from the forces of vibration. But near the end of a Technology and Maintenance Council presentation about vehicle electronics, Paul Menig mused about the way these forces could be captured and put to work.

“Imagine a little sensor with a springboard going up and down,” said the Daimler Trucks North America’s chief engineer, mechatronics, describing the piezoelectric devices that are emerging in laboratory settings. “You can actually create enough electricity to sense something and send it out wirelessly.”

Within one or two decades, vehicle sensors may not require wires at all.

As far-fetched as that may sound, the electronics in a modern truck have evolved at a staggering rate, particularly in the face of tightening emission rules. Kevin Otto, the director of service for Cummins Emissions Solutions, points out the number of sensors and actuators when describing the change. One engine built in 1992 included a mere six sensors and seven actuators. This year, you can find a series of 28 sensors and 15 actuators on an engine block, and some of these actuators even incorporate sensors of their own to help manage different activities.

“The amount of information about the engine has become just staggering,” he said.

In relative terms, it has been a rapid evolution. Electronics didn’t make their first real push into heavy-duty trucks until 1987, when electronic unit injectors began to deliver their precise shots of fuel in the name of improving fuel economy. All heavy-duty engines were not electronic until 1994, and all medium-duty models followed suit in 1998.

New applications for every packet of data emerged along the way. Integrated instrument clusters emerged in the mid-1990s, anti-lock brakes became a reality in 1997, and by the end of the decade, transmission suppliers were starting to incorporate electronics of their own. In addition to simply monitoring factors such as oil pressure and coolant temperature, electronics allowed engine activities to be changed -limiting idle time, managing shifts, and controlling the actions of accessories as varied as fans and brakes.

The Technology and Maintenance Council itself played a role in helping to ensure that the electronic components could speak to each other.

“This organization came up with the j1708/1587 data link as long ago as the 1980s in anticipation of all those computers,” said Menig. “Now people started taking advantage of the data.” Once the j1939 standard was introduced, engines and transmissions were able to share information, and the technology opened the door to support traction control.

In some cases, economics were the only factors to slow a related change. Mechanics who replaced signal flashers every few months would likely have embraced solid state versions of the devices as early as possible, but they didn’t really emerge until 2003 because of costs. (The first solid state designs cost $35 while traditional designs only cost $2.35, Menig notes).

The electronic evolution has also played a key role in the introduction of safety systems such as the air bags in truck cabs, noted Vince Lindley of Volvo Trucks North America.

“The physics of a truck collision are much different than what you see in a car,” he explains. A sensor in the control module is mounted in the bulkhead close to the driver’s right knee. “We’re interested in what the driver is feeling,” he says. Rather than watching for a quick spike in G force, the software monitors deceleration over a period of time.

Other safety systems introduced electronics of their own, from ABS equipment to automatic traction control. Six-channel sensor and control valves emerged, giving every wheel a sensor. “Then not only could we turn air off, but we could turn air on,” Lindley added. And the Power Line Carrier (PLC) standard governing the pigtail between trucks and trailers made it possible to introduce anti-lock brakes on trailers, and set the stage for stability controls that track the position of steering wheels, yaw rate and G-forces.

“If it physically senses the vehicle doing one thing but the driver is doing something else with a steering wheel, there must be an event,” Lindley explains. “These systems can de-throttle the engine, they can apply brakes as necessary, they can also release brakes if necessary … This will become a mandatory requirement in the very, very near future.”

Collision avoidance systems that began with a radar-generated warning and evolved into adaptive cruise control even show the promise of proactive braking and engine de-rating to avoid collisions.

“Active proactive braking will actually be on the throttle as well as cruise control,” Lindley adds. “People have already figured out how to use it.”

Electronics will likely play a larger role to come, Otto agrees, referring to the potential of the widespread use of variable valve timing or Homogeneous Charge Compression Ignition to reduce the amount of NOx from a combustion event. “There are a lot of things that could happen.”

“What drives the future? It’s driven by trying to get more of some things, less of other things,” Menig suggests. Regulators defined by almost every letter in the alphabet -EPA, CARB, NHTSA, NTSB and OSHA -all have rules that could be addressed through electronics. For example, Japan already requires vehicles to have collision warning systems with automatic braking, Europe is about to embrace it, and North American trucks are expected to follow suit.

Requirements for Tire Pressure Monitoring Systems still exist, he adds. “They just haven’t figured out a way to do it.”

“The biggest thing I see out there is carbon footprint regulations,” Menig said during another presentation. “In Europe, there is a goal called Vision 2020 which is trying to reduce the carbon footprint of vehicles by 20% by 2020.” One of the unknown issues is whether the target will be based on 2005 or 2007 figures. And he also expects electrically-powered systems for coolers and condensers, and waste heat recovery.

Every change will also require added training at a shop level.

“You really must follow the OEM recommendations,” Lindley says. “There are no generics on this. You really need to follow the book.”

This year alone, smart devices that have traditionally talked over the older j1587 databus are migrating to the quicker j1939 standard. “You’re not going to get all the engine information you used to get,” Menig says, noting how diagnostics will be affected. In the newest vehicles, however, a central gateway will be used to collect messages from the j1939 bus and put them on the j1587 datalink.

And he expects more in the way of dedicated links for gauges, or from one engine control to the next, some of which will run at baud rates that are 50 to 100 times faster than the data links being replaced.

“There are lots of ideas about what the future holds,” he adds, asking for a quick show of hands from people in the audience who own noise-canceling headphones. (Plenty of hands went up throughout the crowd).

An option such as a vibration cancelling seat is not too farfetched, he suggested.

The electronic evolution shows no sign of stopping.


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