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Spectator
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Discussion Starter · #1 ·
noahe & I had a discussion in the Cooper S forum about the Bosch DSC system, and I was curious about how these systems worked. Thought it was time to start a new thread on the subject, even though it's been covered before (but only on a "what is it good for?" basis).


Regarding EBD:
On the Jetta GLX I had, VW used a valve attached to the rear axle beam to do essentially the same thing. Load the car up, and the valve allowed more fluid to go to the rear brakes. With an all-electronic system I'm at a loss to explain how it might work. Measuring the torque on the axle could be done by using the wheel-mounted ABS sensor and another mounted near the differential. The difference in signals would indicate how much the axle is twisting, and thus the amount of torque present.

I had a look on the Bosch site, for info on the DSC G-sensor, which was interesting. Apparently there isn't a spinning gyroscope at all -- just a weight whose movement gets detected via capacitance. All contained in a surface-mount device about 1 cm^2. According to their site, this one device can be used in ABS, DSC, Active Suspension, and headlight leveling. For three-axis sensing you'd have three of them, one each mounted in the X, Y & Z planes.

Hmmm. Headlight leveling. This same technique might apply to the EBD issue - instead of using a physical valve to adjust the flow of brake fluid to the rear brakes, use one of these sensors to detect if the vehicle is loaded down or not (sagging in the rear, so to speak), and then use the existing ABS valving to adjust for the condition.

Chip H.
 

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Spectator
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Discussion Starter · #2 ·
Came across this image. Somehow I don't think EBD will help this person.:eek: :eek:

Chip H.
 

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The DSC in the MINI has a transverse acceleration sensor and a sensor to measure the rate of rotation integrated into one black box kust behind the hand brake lever.

MINI headlight levelling (Xenons) is based on two height level sensors (levers on the left hand side front and rear suspension components that actuate a potentiometer). This variance is then decoded into the respective angle on the headlamps.
 

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Spectator
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Discussion Starter · #4 ·
Re: Re: How DSC/EBD/CBC works

InsiderMINI said:
The DSC in the MINI has a transverse acceleration sensor and a sensor to measure the rate of rotation integrated into one black box kust behind the hand brake lever.
That must be the Bosch unit I read about. The location puts it pretty near the centroid of mass for the car, so as to get more accurate readings.

[MINI headlight levelling (Xenons) is based on two height level sensors (levers on the left hand side front and rear suspension components that actuate a potentiometer). This variance is then decoded into the respective angle on the headlamps.
Sounds like a pretty simple analog circuit then. Probably a lot cheaper than the Bosch chip, which would require a connection to the car's data bus. Any idea how protected it is from dirt intrusion?

Chip H.
 
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