this was in the automotive section of the local paper
Techies go wild at DaimlerChrysler by Richard Russell
ASPEN, Col. -- When it comes to all-wheel-drive and elaborate chassis electronics, the names Chrysler and Dodge don't usually come to mind.
Yet, the engineers and technicians at Chrysler, with help from their German parent Mercedes, are offering a wide variety of sophisticated, full-time systems in a number of cars and light trucks.
Not only that, but the same group of techies behind the Pentastar badge have packaged them with stability and traction control systems, roll-control technologies and ABS. This inter-relation between systems is a perfect example of how sophisticated today's motor vehicles have become.
We recently spent considerable time with Chris Barman here during a winter-driving and chassis technology workshop. This diminutive lady holds the cumbersome title of senior manager, active chassis controls, system integration, electrical and electronics core, Daimler Chrysler.
Although a mechanical engineer, Chris has been involved in electronic stability control since its inception. She's worked with Mercedes in Germany and now heads a group at Chrysler designing, developing and massaging the tangled web of mechanical, hydraulic and electronic systems that comprise a Chrysler or Dodge stability and traction controls and related systems like ABS. Mercedes is sending engineers to her team to learn the ropes.
Obviously excited by the gains made in recent months in terms of both hardware and software, this car nut and gifted driver loves to talk about the difference programming can make.
The early German units were highly intrusive, intervening abruptly at the first sign of lateral slippage, shutting off power and applying the brakes at the appropriate wheel. While safe, such systems take away the fun of driving for those who want to experience some loss of grip at the rear.
Writing different lines of computer code has enabled Chris and her group to tweak the systems so that take-over of control is less abrupt and more subtle. If you want to deliberately switch it off, you can have a whale of a time on a snowy or icy surface.
"The four-channel ABS system in the Caliber, for example, controls each wheel separately. The sensors at each wheel also talk to the electronic clutch which works on demand, driving only the front wheels until power is needed at the rear."
The new 2007 Dodge Caliber not only stands apart from the small car, entry-level crowd in offering all-wheel-drive, it has a very sophisticated system. Standard on the top-end R/T model at $19,985 ($24,995 Cdn.) is an electronically-controlled coupling in the rear differential that controls the distribution of power front to rear.
The Caliber is essentially a front-drive car in normal conditions, but will quickly divert power to the rear wheels when traction at the front lessens. Where the Caliber system differs, and where engineers like Barmen do their thing, is programming the electronics in the system to anticipate conditions where power should be sent to the rear wheels, conditions like accelerating from rest and driving on slippery roads.
"AWD is also utilized on dry pavement at speeds between 25 and 65 miles per hour to enhance handling during performance driving," she said.
Systems available on Chrysler and Dodge vehicles
>Full-Time, Mechanical All-Wheel Drive: Sends power to all four wheels all the time. Three different versions are used, one for the Chrysler 300 and Dodge Magnum, one in the Pacifica and a third in the Durango.
>Two-Speed, Full-Time, Mechanical All-Wheel Drive: Power to all four wheels all the time, but adds a selectable low-range for adverse conditions. Available on Dodge Dakota and Durango.
>Electromagnetically Coupled All-Wheel Drive: An on-demand system that sends power to the front wheels until slippage dictates the need to send some to the rear, also used on dry pavement until 65 mph during performance driving. Available on Dodge Caliber.
>Anti-Lock Brake System (ABS): Prevents lockup of individual wheels during braking by reducing brake pressure to the affected wheel to provide maximum pressure without lockup. Available on all Chrysler and Dodge vehicles. Systems available on Chrysler, Dodge and Jeep vehicles
>Electronic Stability Program (ESP): If the system detects a difference between where the driver intends to go, judged by the steering wheel angle, and where the vehicle is actually headed, ESP uses selective braking at individual wheels and throttle control to put the vehicle back on the intended path. Availability: Chrysler Crossfire and 300, Dodge Caliber, Charger, Magnum and Durango; Jeep Commander, Grand Cherokee and Liberty.
>Electronic Roll Mitigation (ERM): Observes vehicle attitude and lateral forces, estimating the rollover potential. Applies a burst of full braking power to the appropriate wheel to stabilize the vehicle by reducing lateral forces. Available on Dodge Durango; Jeep Commander, Grand Cherokee and Liberty.
>Traction Control: Helps to prevent drive wheels from spinning during acceleration and at slow speeds by applying the brakes to the slipping wheel. All-speed traction control adds throttle control to reduce engine power as necessary top prevent slippage. Traction control available on Chrysler Pacifica, PT Cruiser, Sebring, Town & Country, Dodge Caravan and Stratus. All-Speed Traction Control on Chrysler 300, Crossfire, Dodge Caliber, Charger, Durango and Magnum; Jeep Commander, Grand Cherokee and Liberty. Richard Russell owns and operates Advanced Driving Concepts and is president of the Automobile Journalists Assciation of Canada. [email protected])