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Porsche used injector shut off as far back as 1973. I owned a 1973 911T with mechanical injection. Each cyclinder had an air intake and a in head injector. The was a controller called a 'transducer' about the size of a pack of cigarettes. It was just an electromaget for the tach and a small printed circuit with a few transisters for solenoid control] It controlled the tach and the injector solenoid. When you took you foot off the accelerator, the solenoid would retrack, shutting off the injector pump. When the tach dropped to 1200 rpm [no matter the vehicle speed] the transducer would send a signal to the solenoid to allow the injector pump to operate so the engine would not stall.
IIRC, the fuel control solenoid on this set-up only brought the fuel delivery back to a minimum rate, not shut off the fuel completely. These mechanical fuel injection systems were very problematic on the running characteristics at small fuel delivery rates; a complete shut off of fuel and then the tipping in would result in popping in the intake manifold as the mixture was way too lean. Similar set-ups were found on everything from the Bosch to SPICA to Kugelfisher mechanical injection systems on the Euro cars for a few years and that hastened the development of the electronic fuel injection systems to follow; even diesel engines have moved from mechanical fuel delivery to electronic due to the ability to meter and deliver fuel more precise control.
The upper cylinder still needs lubrication.
fuel is a lube.
Some needs to be injected when coasting.
If no fuel was injected you would quickly come to a stop.
Give it a try drive down you road and let off the throttle.
How far do you go?
Now do it again and this time turn off the ignition.(but don't lock the wheel)
I bet you come to a stop rather quickly compared to coasting.
The upper cylinder still needs lubrication.
fuel is a lube.
Some needs to be injected when coasting.
If no fuel was injected you would quickly come to a stop.
Give it a try drive down you road and let off the throttle.
How far do you go?
Now do it again and this time turn off the ignition.(but don't lock the wheel)
I bet you come to a stop rather quickly compared to coasting.
Although my car brings fuel delivery to a minimum, it has been confirmed that some cars actually stop delivering fuel altogether while coasting.
I thought FI was different than carburators (sp) at high altitude. A friend says he bought a FI atv and rode on trails in Rocky MTNS in CO and it was not running right. Took to dealer and was told set at factory to run up to 8000 ft only. Needed adjusted for above that.
I've read about the fuel shut off, but I'm confused when it comes to the actual application on my vehicles. Our Explorer has the computer that shows instant mpg. Coasting down a hill in gear and I can get 50-60mpg on the display. Shift to neutral on the same hill, and it spikes up to 100 or so mpg. Same thing on our two Vibes using an OBDII adapter, but the mpg is more like 140 in gear and over 200 mpg in neutral. This is contrary to what I've read that new cars use less fuel in gear due to the transmission keeping the motor turning, but when you shift to neutral, the computer has to use more fuel to keep the engine at idle. Confusing, to say the least.
Did I say you will skid to a stop? no.
I said you will stop. why as you said the engine will drag you down , to what? a stop?
You will not just go, coasting along.
Quote:
Originally Posted by MustangEater82
You would coast to a stop. You don't suddenly lock up and stop when you kill fuel to the engine, the engine drags the car down.
...
The upper cylinder still needs lubrication.
fuel is a lube.
Some needs to be injected when coasting.
You'd better do some research. "Decel fuel cutoff" has been standard on most vehicles for years (well more than decade). Ford had this to say about even more technology that they call "Aggressive Deceleration Fuel Shut-Off"--already implemented on some vehicles:
Quote:
We are deploying Aggressive Deceleration Fuel Shut-Off technology to improve fuel efficiency. ADFSO allows fuel supply to the engine to be shut off during vehicle deceleration and then automatically restarted when needed for acceleration or when the vehicle’s speed approaches zero. This new system builds on the Deceleration Fuel Shut-Off technology available in our existing vehicles by extending the fuel shut-off feature to lower speeds and more types of common driving conditions, without compromising driving performance or emission.
This improved fuel shut-off will increase fuel economy by an average of 1 percent. An additional benefit is increased deceleration rates, which should extend brake life and improve speed control on undulating roads.
Starting in 2008 this technology was implemented on the Ford Flex, F-150, Expedition and Escape and the Lincoln MKS and Navigator. We are continuing to implement it as we bring out new vehicles. For example, the 2011 Ford Edge, Ford Explorer and Lincoln MKX use ADFSO. The ADFSO technology will be a standard feature in all of our North American vehicles by 2015, and we will continue to expand implementation globally.
The length of these acronyms is getting ridiculous.
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