Engine starting and stopping..
Engine starting and stopping..
(OP)
I have a basic(silly!!) doubt about it.. When an ic engine(say 4 stroke) stops, it may stop at any position. When an engine is started, fuel supply and spark is given. But how its possible that it starts to run again in the same direction(CW-CCW)??
I mean, it should run in the same direction, but whats the mechanism which makes sure that engine runs in the same direction??
I mean, it should run in the same direction, but whats the mechanism which makes sure that engine runs in the same direction??





RE: Engine starting and stopping..
RE: Engine starting and stopping..
If you get old enough, like my family's 1910 Michigan, then the electric starter does not guarantee rotation direction. The starter works by filling the cylinders with an explosive gas, then you press the button and all 4 cylinders fire hopefully spinning the motor in the right direction and not melting a hole in a piston. Needless to say we use the hand crank to avoid the problems with the starting system.
Luck is a difficult thing to verify and therefore should be tested often. - Me
RE: Engine starting and stopping..
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Engine starting and stopping..
Now a direct injected engine, diesel or gasoline, doesn't depend on the pumping action for chemical energy, but I'm pretty sure no electronic engine is going to allow itself to run backward, even if it were capable. That leaves mechanical diesel engines. Well, they depend on mechanically driven mechanical pumps for their chemical energy. I'm going to go on a limb here and say in-line and distributor pumps are not going to be delivering fuel to the injectors when turning backwards. That leaves mechanical unit injectors. Hmmmn, it just might work! (injection timing would suck, though).
RE: Engine starting and stopping..
Carnage1, id like to know more about your 1910 Michigan..
Im totally unaware of the starters and motors you guys are talking about. Please provide me with some links, so that i can understand deeply.... and we are talking about ic engines only right??
Thanks again for replying me friends..
RE: Engine starting and stopping..
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Engine starting and stopping..
they have two camshafts for optimal performance in each direction
when the skipper wishes to change direction, fuel feed is stopped, compressed air injected into the cylinders timed to reverse the direction of the crankshaft, meanwhile the camshaft is swapped, then fuel feed is restarted. If the fuel is restarted before the crankshaft changes direction, the engine will continue to run forward on the backward cam, but it runs very rough.
The super chargers or turbo chargers continue to run in the same direction while the engine runs in either direction
Hydrae
RE: Engine starting and stopping..
RE: Engine starting and stopping..
Hydrae
RE: Engine starting and stopping..
Easy, you just put a twist in the belt
- Steve
RE: Engine starting and stopping..
Ive voted for u.. lot many times..
Let us see guys if someone can come up with a better explanation.. So lets keep it going..
RE: Engine starting and stopping..
I think you are right. Althought the actual HP pumping elements don't know or care which way they are going, the supply pumps (I think DPA/DPC/DPS use vane pumps) are going be running the wrong way to work.
- Steve
RE: Engine starting and stopping..
2 Oct 08 21:23
... when its started again by an explosion ...
What engines are started by an explosion? Everything I am familiar with has some form of electrical starter, air starter, kick starter, pull starter, spring starter or hand crank. None of these is going to start the engine in the reverse direction. I know of no four strokes that will run backwards.
Lots of 2 strokes will run backwards but the spark timing will be way late so they make very little power. Glow plug two strokes on the other hand will happily run backwards. Some of those are most easily started by turning them backwards & the first combustion event will reverse direction & make them run forward.
Engines almost always stop as they are coming up against a compression stroke. Almost never on an expansion stroke. Multi cylinder engines are less consistent as the forces are more nearly balanced.
RE: Engine starting and stopping..
You explained almost everything..
RE: Engine starting and stopping..
RE: Engine starting and stopping..
Anyone know how that works?
Hydrae
RE: Engine starting and stopping..
When you press the button, it cuts fuel, then as the engine coasts down the ECU predicts the stroke at which the engine will fail to get over the next compression stroke, and gives that cylinder a squirt of fuel, then fires the spark plug the moment the engine comes to a stop on that compression stroke ... presto, the engine then runs backwards. Saves having to make a forward/reverse gearbox. Presumably this offsets some of the extra cost of the fuel injection and emission control apparatus.
But the normal starting mechanism is only capable of rotating the engine in the forward direction, as per standard practice.
RE: Engine starting and stopping..
That is a Kaufman or hot gas starter, an explosion from a cartridge is turned into a stream of hot gas to spin an engine up to speed for start. Lighter ,yes, more reliable , not always.
B.E.
RE: Engine starting and stopping..
RE: Engine starting and stopping..
RE: Engine starting and stopping..
RE: Engine starting and stopping..
RE: Engine starting and stopping..
RE: Engine starting and stopping..
Explode" at random. The charge is ignited by the spark plug. If the engine starts to run backwards it will be sucking in the exhaust and blowing out the carb. You can't get any fuel that way so it stops instead of running backwards.
Old diesel powered Caterpilars would sometimes kick bak when lugged down badly. They would suck air in the exhaust and blow out the air cleaner. In those days the air cleaners were oil bath. Another scenario was backing up a hill at the end of the day and running down the hill in the morning to start the engine. If you forgot to shift out of reverse before starting the Ccat would start and run backwards. This was not good for the engine for several reasons. The operator did not enjoy the face full of oil he usually got when the exhaust started issuing from the air cleaner.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Engine starting and stopping..
Static-start engine
Another way to provide for shutting off a car's engine when it is stopped, then immediately restarting it when it's time to go, is by employing a static-start engine. Such an engine requires no starter motor, but employs sensors to determine the exact position of each piston, then precisely timing the injection and ignition of fuel to turn over the engine.[2]
This was from a Google search for "Static Start Engine"
This is the only info I could find on it.
Bud Trinkel, Fluid Power Consultant
HYDRA-PNEU CONSULTING
RE: Engine starting and stopping..
<<<BREATHE AUTOMOTIVES>>>
-Harish