electronic throttle
in [Technical]
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From: Cameo on 9 Mar 2010 02:11 "News" <News(a)Group.Name> wrote in message news:3P6dnbw6u7pE6QjWnZ2dnUVZ_oOdnZ2d(a)speakeasy.net... >>> Wasn't the same cause suspected in the recent Airbus plane crash in >>> the Atlantic, just off the South American coast? > > > No, that was suspected pitot probe icing, but no conclusive report has > been issued and the search for the bulk of the wreckage continues. Thanks, you're right; I remember now that they mentioned the Pitot tube.
From: David Skelton on 9 Mar 2010 06:29 >>>>We have had three cars (one made in 1997, the second in 2002 and the >>>>third >>>>in 2004) that sometimes used to open the throttle on the 'over run', >>>>possibly to reduce emissions. >>>> >>>>It was unnerving approaching junctions. >>>> >>>>All three had mechanical throttle cables, but also motors built into the >>>>throttle body to drive the throttle plate open. This used to happen mostly when in a long slow moving queue of traffic. With the engine on tick over in second gear at about 10 mph, if the clutch pedal was pressed down, then released unexpected acceleration was the result, boy did they take off. I think that was pretty dangerous if it was an older driver whose reactions are slower. >>>>--- news://freenews.netfront.net/ - complaints: news(a)netfront.net --- >>> Virtually ALL port injected engines have an electrically operated >>> "idle speed control" or "air bypass" valve that bypasses air past the >>> throttle valve for several purposes. It is uded to raise (or maintain) >>> idle speed when AC is operated, headlights are turned on, or power >>> steering is used at idle, and it is used to prevent abrupt throttle >>> closure on decel for emission reasons. >>> Some older vehicles used an "idle up" solenoid for the same purpose, >>> while others had an "anti-diesel" solenoid to close the throttle >>> completely when the ignition was turned off. Other older vehicles used >>> a "dash pot" or vacuum idle control to do some of the same. >>> >>> Vehicles with Drive By Wire, in large part, eliminate the ISC system - >>> which, by the way, is one of the more problem prone subsystems on most >>> fuel injected vehicles of the last 20 years or so. >> >>All three had the "air bypass" valve too. >> >>I do not know what you mean with "ISC system". > > Idle Speed Control Oh yes, of course. >> >>BTW, I have known some discreet electronic components that have failed due >>to being used too near the maximun demand for too long, would you not >>consider that to be 'wearing out' ?? >> > > They fail from overheating, generally - and then USUALY from being > under-spec'ed. Agreed > Capacitors have a finite life - but using a 135C rated cap instead of > an 85C rated cap makes it last WAY longer. Something like double for > every 5 degrees below spec, and half for every 5 above. Not 100% sure > of the number - but very close to that from what I remember. And that > is for aluminum electrolytics. > Solid tantalum and dry Mylar caps last virtually forever if not run > way over the rated voltage. > > Any discrete component run too close to the limit in a vehicle control > system constitutes BAD engineering. Virtually all automotive > electronics spec 135C rated parts, ar at the VERY minimum, 105C. > > Commercial grade is 85C, and they fail in personal computers a lot > faster than the higher grade 105s. >>Best wishes >> >>David >> >> >> >>--- news://freenews.netfront.net/ - complaints: news(a)netfront.net --- > --- news://freenews.netfront.net/ - complaints: news(a)netfront.net ---
From: C. E. White on 9 Mar 2010 09:16 "Dave" <hairy411(a)hotmail.com> wrote in message news:7vj8brFrhvU1(a)mid.individual.net... > You have never driven a vehicle with vacuum actuated wipers, have > you? Not a fair comparion. Vacuum wipers need a constant supply of vacuum and can require vacuum literally for hours. The power brake booster is actually a reservoir and "stores" enough vaccum to provide assit for several stops. As long as you don't pump the brakes, you don't "consume" vaccum. When you apply the brakes, the booster assists by applying outsie air pressure to one side of the diaphram. Look at http://image.mustangmonthly.com/f/9166114/mump_0209_understanding_ford_brakes_14_z_power_brake_booster_diagram_vacuum_open.jpg When you step on the brake, the port to the vacuum reservoir is closed off and a port to atmospheric pressure is opened on th ebrake pedal side of the booster. You only use a little bit of your "stored vacuum" ("stored vaccum" is sort of a backwards concept to me, but you can think of it in that manner). If you press very hard on the brake pedal, you won't loose any more vacuum, even if the engine isn't providing any more - the check valve on the vacuum source line prevent flow back towards the engine, and as long as the pedal is pressed hard, the vacuum port to the pedal side of the booster is closed as well. Ed
From: jim beam on 9 Mar 2010 09:22 On 03/09/2010 06:16 AM, C. E. White wrote: > "Dave"<hairy411(a)hotmail.com> wrote in message > news:7vj8brFrhvU1(a)mid.individual.net... > >> You have never driven a vehicle with vacuum actuated wipers, have >> you? > > Not a fair comparion. Vacuum wipers need a constant supply of vacuum > and can require vacuum literally for hours. The power brake booster is > actually a reservoir and "stores" enough vaccum to provide assit for > several stops. As long as you don't pump the brakes, you don't > "consume" vaccum. When you apply the brakes, the booster assists by > applying outsie air pressure to one side of the diaphram. Look at > http://image.mustangmonthly.com/f/9166114/mump_0209_understanding_ford_brakes_14_z_power_brake_booster_diagram_vacuum_open.jpg > > When you step on the brake, the port to the vacuum reservoir is closed > off and a port to atmospheric pressure is opened on th ebrake pedal > side of the booster. You only use a little bit of your "stored vacuum" > ("stored vaccum" is sort of a backwards concept to me, but you can > think of it in that manner). If you press very hard on the brake > pedal, you won't loose any more vacuum, even if the engine isn't > providing any more - the check valve on the vacuum source line prevent > flow back towards the engine, and as long as the pedal is pressed > hard, the vacuum port to the pedal side of the booster is closed as > well. > > Ed > > "duck" and cover, right ed? -- nomina rutrum rutrum
From: cuhulin on 9 Mar 2010 10:40
Thank Gawd for electric windshield wipers! I have owned a few vehicles before that had vacuum windsheld wipers, give me electric windshield wipers any day.My 1914 Ford Model T has a hand operated windshield wiper. cuhulin |