It seems to me that a fuel injected car could be started without a starter motor. The computer could instruct the fuel injector to shoot a burst of fuel into the cylinder ready to be fired and ignite it. I’m sure I’m not the only one that has wondered about this.
What am I overlooking here or are any auto manufacturers doing this already?
Neat idea. I like it and would like to see it implemented, so I’ goin to try and shoot holes in it.
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Backyard mechanics. Every now and then you just need to bump the engine over by disconnecting the sparkplugs and cranking the starter. This system would make that a tad tricky.
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Cylinder position. A crank trigger should tell the computer where each cylinder is. What effects would creating a power stroke have on a cylinder that is not near TDC?
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Compression. The fuel/air mix only explodes when it is sparked off AND compressed (anywhere from 8:1 on up 11:1 in most cars). How could this system adjust for that.
I’m sure I’ll think of more later today. Discuss.
You’re overlooking compression. The electronic control systems do sense crankshaft and camshaft position, which are among the factors used to effect the ignition timing. But a spark plug generally won’t ignite a non-compressed mixture of gas and air, and if it did it wouldn’t produce enough force to get the engine running.
I think the compression requirement is the killer. The engine creates this compression through the momentum of the engine. No momentum, no compression.
Suck, bang, blow.
Gotta have all three, not just the bang.
That should be “suck, squeeze, bang, blow.”
You need a compression stage. That’s the principle of operation for internal combustion and turbine engines. Also most massage parlors.
You may note fuel injection in gaslone engines isn’t into the cylinder but in the intake port just outside the valve or in the intake manifold. Only diesel engines inject fuel directly into the combustion chamber.
IIRC there is a system similar for what you want to do for aircraft engines but it used an explosive catridge. Still far inferior to a starter motor.
Yeah, but suck, squeeze, bang & blow is a lousy name for a bar.
Right Padeye I did not realize that the injector does not have direct access to the cylinder. That would make in tough since the intake valve would be open.
But after googling for a while I found that this has been done without compressing the “first-to-fire” cylinder. This motor has an electric valve train. So the intake valve is opened, fuel shot in, intake valve closed, then cylinder fired. Even without compression it provides enough bang to compress the next cylinder.
What if you were to directly inject fuel, like a diesel, AND inject oxygen?
Would this system be more prone to breaking than simply giving the motor a spin with an electric motor?
The electric starter is a wonderful invention. Reasonably durable, cheap to install, and effective. In use about 100 years.
As the OP said, somebody has thought of it before. General Motors engineers were giving it serious considering ditching the cranking motor as early as the middle '70s. The cylinder at or just past TDC already has a fuel-air charge. Some compression may have leaked out around the rings, but you’d still get enough of a bang to get to the next cylinder’s firing.
The main thing that kept GM from ditching that heavy starter was the “what if” factor. There are a few dozen conditions that would keep that first bang from happening. No first bang, no start. They couldn’t bear the thought of some guy in a cashmere coat trying to start his Cadillac with a crank.
Yeah, I’m guessing autos with electric motors powered by hydrogen or batteries or whatever will replace the internal combustion engine before anyone would invest in major changes to the ICE.
I forgot to say where I learned that stuff. I got it from Bruce Gribben, Sr., who invented the overrunning roller clutch that we know as a “Bendix.” He worked for Delco Remy, which at the time was a division of General Motors.
Great info thanks AskNott.
I just realized I posted a dead link…I will try to find it again and cntl-v instead of shift-v.
I also think trying to turn over an engine from a dead stop with the power of one combustion chamber would be a bad idea.
Also, unless everything is working 100% perfectly, an engine usually requires several revolutions to start.
There are (or were) aircraft engines which use explosive cartridges in place of a starter motor to save weight.
The direct injection problem is a tertiary problem. Either there would be a switch to direct injection or with newer electronically controlled valves the intake valves could be opened to let fuel/air in and then closed to allow for compression.
Could compression be overcome with a supercharger running off of an electric motor? Use it to shove some high pressure air in the cylinder first, then add fuel, then ignitie. Although that just adds another electric motor to replace the starter.
HIJACK
In that case, people like me would have to have acess to a supply of pure oxygen for my car. Well, my car and the 4th of July…and Christmas… and barbeque’s.
/HIJACK
Yes and on cold mornings they used to litter the ground with expended cartriges trying to get a start.
Large aircraft engines, at least the radials, used an inertial and not a direct-drive starter… A reltively small electric motor slowly brought a flywheel up to high rpm, the flywheel was then disengaged from the motor and engaged to the engine for start. The engine was also primed with a hand pump in the cockpit to make sure that there was fuel in the cylinders for starting.