06-19-2009, 02:51 PM | #1 |
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Electro-Mechanical E-Brake
Just curious - FWIW
I'm aware the "P"/e-brake is a electro-mechanical device actuated by a switch, rather than a purely mechanical lever. The curious thing is this: is it held by battery power only (I assume BMW engineers wouldn't do it that way) or is actuated by an electrical solenoid that engages a fail safe mechanism? Is it in the transmission like a conventional parking brake, or does it actually apply force to a conventional disk (inner drum) brake at the rear wheels? Again, just a curiosity - never heard anyone complain about it. Some of the new BMWs continue to employ a purely mechanical e-brake lever, so it got ta think'n . Last edited by teagueAMX; 06-19-2009 at 08:39 PM.. |
06-19-2009, 06:30 PM | #2 |
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Good question.
I use the auto park at long stop lights and it lets just drive off so was wondering if it was link to trans somehow. hopefully someone can enlighten us. |
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06-19-2009, 08:22 PM | #3 |
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Sales person told me auto park feature "gently" sqeeze's brake rotor with same brake pads used to stop the car.
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06-19-2009, 09:08 PM | #4 | ||
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Quote:
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I'm sure our bimmer friends have thought it but what if your battery goes dead, and you car is on an incline, what keeps the e-brake engaged; would it roll? |
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06-20-2009, 05:19 AM | #5 | |
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This is how bmw explain it:
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I'm a fan of these "auto-release on gas" button type parking brakes - it's a little aggressive in terms of when it applies via the auto-hold but that's just something to get used to. |
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06-20-2009, 10:19 AM | #6 |
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That's excellent. I knew BMW thought it through very well. I just didn't know how they did it. So for the most part the backbone of the systems are conventional mechanical systems, that happen to be controlled by electronics. I particularly liked the part that says:
"If the engine is switched off, electromechanical brake cables support the function of the conventional handbrake." Just to give you an idea about how anal I am about certain things. Back in the mid-1980's I purchased a new car with full electronic engine control. After parking it in my driveway I lifted the hood and disconnected a computer control plug to see if the thing would run with out it. A dashboard light came on, the idle was a little rough, but it ran OK. You could even drive it that way if you had to. I put together computers back in those days and knew how unreliable they could be so it was reassuring to have that knowledge. I used to be that way about elevators, too, but after researching all the safety features, no problem. |
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06-20-2009, 10:42 AM | #7 |
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I had an a5 before the x6 and that had a button-brake that released on gas (didn't auto-apply though). You could feel that mechanically "ratchet" the park brake when the button was pulled - the x6 is a lot less obvious about it.
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