Are any cars currently in production with direct injection designed so they can be be started even if the starter motor doesn't work, at least in most cases, by having the computer choose a cylinder that has its valves closed and its pistons in the power stroke position? At least are direct injection cars designed to help the starter by doing that?

won't work. for diesels, it's not the pressure of the compression stroke that ignites the fuel, it's the adiabatic heating the compression causes. once an engine stops, the heat in any compressed air charge quickly dissipates. once gone, nothing you inject will ignite. for gasoline, while the adiabatic heating it not as extreme as diesel, it's still present and very much crucial to vaporize the air/fuel mix when charged, and to raise its temp to the point where the spark will "tip it over the edge" and ignite. for either engine, the crank never comes to rest at or near the very top of the stroke on switch-off. the more pistons, the closer you might be to having one of course, but for most common 4, 6 or 8 cylinder engines, no cylinder will be compressed quite enough. it's also hard to have the engine computer "choose" which piston to try and fire - most systems only know one spot on the crank, and that's tdc on #1 piston. and that's not known until the sensor is...

Can direct injection engines start without a starter motor?

Sep 09, 2011 24 Replies

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Nate Nagel 12 years ago

He did specify *direct* injection; 2000 psi is about in the ballpark.

Another thing I forgot in my previous post - at least for BMW, the high pressure fuel pump is engine driven, not electric - if pressure has bled down while the engine is off (not unusual; I've already replaced one leaky injector) there will be no ability to inject fuel until the engine turns over a few times.

nate

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Nate Nagel 12 years ago

Looks like Bosch has been working on this, but apparently it's only practical as a backup mechanism.

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nate

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JR 12 years ago

Google,,, American Car Prospector His name is John Hames. He drives aro und (mostly in Colorado) looking for certain cars to buy and then sell to b uyers on a list he has. Not long ago he bought an old Corvette that has a w eird looking mechanical fuel injection system on it. On my Comcast TV chann els line up, his show is on the Velocity TV channel on Sundays.

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T0m $herman 12 years ago

Who needs a starter motor? I was able to push my 1994 Civic Si far enough up a hill to bump start it with a nearly completely flat battery.

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T0m $herman 12 years ago

And on some aircraft - hand-propping is scary.

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