23 votes

Do pistons keep moving when the car stops?

The answer to your question is both yes and no. Yes in majority of the conventional vehicles, the pistons keeps moving even when the vehicles is at a stop light. The idle RPM, which is usually ...
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  • 576
12 votes

Do pistons keep moving when the car stops?

In most cars, yes the engine continues to rotate and the pistons go up and down in the cylinder bore due to combustion and the engine continuing to run. Some vehicles have an "auto stop" feature which ...
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10 votes
Accepted

Why do combustion chamber combustion gasses turn the engine when it only burns?

During combustion, the pressure in the combustion chamber is increased, and this pressure pushes down the piston. There are two reasons for this: Increase of the amount of gas molecules Let's say we ...
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  • 6,997
6 votes

How long do the entire combusting cycle take?

math it out. we will use 3 RPM readings that will math out easily, and give a good idea of how fast things are happening at different engine speeds. 600 RPM - This is about idle speed. 600 ...
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  • 8,393
5 votes

Could Hydrogen Be Used as a Fuel?

Hydrogen is an ideal gas to be used for combustion, as there are no harmful emissions byproducts if the combustion (combination of hydrogen and oxygen) is at the proper ratio. You just make pure ...
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  • 12.2k
5 votes

Do pistons keep moving when the car stops?

To add to the other answers, in a manual vehicle, the road wheels are usually disconnected from the engine when at a stop either by putting the transmission in Neutral, or by depressing the clutch ...
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5 votes
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Steam Engines - What are these things?

In the early automotive days, steam-powered cars were more common than anything else. Disadvantages of steam power for automotive use, as compared with the internal combustion engine: Inefficiency. ...
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4 votes

Why do combustion chamber combustion gasses turn the engine when it only burns?

AFAIK the way this works when you burn the fuel, you have it in liquid state at atmospheric pressure. In actuality you're not burning the liquid, you're burning the vapors that form over the liquid. ...
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4 votes
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External Combustion Engines - What are these things?

Heat engines (in thermodynamics) convert thermal (or heat) energy to mechanical energy. Heat engines typically work by utilizing the expansion of a gas and/or liquid as it is heated. External ...
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4 votes
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What are the basics of the combustion cycle in wankel (rotary) engines?

Just like a conventional piston engine with poppet valves (Otto cycle), Wankel engines operate on the four-stroke cycle (suck-squeeze-bang-blow). This Wikimedia animation succinctly describes it: ...
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3 votes

Could Hydrogen Be Used as a Fuel?

Hydrogen has been used as a fuel in various experiments. The largest-scale experiment I'm aware of is the BMW Hydrogen 7, a 7-series V12 produced from 2005-2007. About 100 were built. This engine ...
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  • 4,402
3 votes

Do pistons keep moving when the car stops?

I don't have enough reputation to comment, but the small economy cars (K or Kei cars) in Japan also have this StopStart feature, as Mauro commented (for European cars). I think this feature is now ...
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3 votes

Steam Engines - What are these things?

Actually, you see, the internal combustion engine replaced the steam engine to power vehicles of all kinds. It was originally used in locomotives in the 1800s to connect the east cost of the US to the ...
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3 votes
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Could Hydrogen Be Used as a Fuel?

You can use hydrogen gas, yes. The main problem is that it is not easy to make. Most hydrogen (about 95% of all hydrogen used today) is produced by partial oxidation of methane and coal gasification, ...
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3 votes
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Why can't they add more gas particles to the pressure higher to force a piston down!

What you are proposing has been done a few times: there are cars that run on compressed air. The problem with that is that compressed air has a low energy density, comparable to lead-acid ...
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  • 4,402
2 votes

Why can't they add more gas particles to the pressure higher to force a piston down!

The amount of energy required to force that amount of gas into the cylinder is immense. Causing a large enough pressure difference to force the piston down and drive the engine, and also the vehicle, ...
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  • 3,002
2 votes

What would happen when if fuel is added during the combustion process?

The short answer is "it depends." Gasoline engines would ideally run with a stoichiometric mixture – just the right amount of fuel and air to produce complete combustion. Now in reality you don't ...
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2 votes
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Is it possible for me to see oxygen, caused by valve overlap, in the exhaust gases?

TL DR: I would suggest you have an exhaust leak up stream of the sensor location. I know you said it doesn't have a leak, but I'd suggest you just haven't recognized it. Valve overlap only occurs ...
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2 votes
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Simple Question: During combustion stsgep do the piston go up all the way?

TL DR: You are absolutely correct: the piston does not completely close the gap. There are two points in the rotation of the crankshaft where the piston stops momentarily as it changes direction: ...
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1 vote

Simple Question: During combustion stsgep do the piston go up all the way?

All engines are designed with a swept volume (the volume the piston moves through) and a clearance volume (the space between the head and the piston once it is at the top of its stroke). The ratio ...
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1 vote

Why can't they add more gas particles to the pressure higher to force a piston down!

They do; it's called forced induction and is commonplace across most modern vehicles. The use of a compressor, typically a Turbocharger (although sometimes a Supercharger) means air at higher than ...
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1 vote
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During Combustion how important is it to have an even burn?

As method 5 mentioned it is important for gas engines and not as important for diesels. In a gas engine in a car you can foul spark plugs, catalytic converters, and create carbon deposits not to ...
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  • 2,849
1 vote

More In Cylinder Pressure Testing Questions

I did some searching on IATN and found known good pressure waveforms that are identical to my after repair captures. Unfortunately I can't post them here. It turns out that hump is completely normal. ...
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  • 10.7k
1 vote

Could Hydrogen Be Used as a Fuel?

Yes but it would be impractical for Internal combustion engines. Though hydrogen has a very high energy density per kg, producing it, compressing it and storing it just to lose 70% of it's potential ...
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  • 1,323
1 vote

How much pressure in ATMs is acting when a combustion happen?

There is no fixed pressure.. However it is not uncommon for ordinary petrol production engines to have an initial post spark pressure at peak power of around 68Atm's. Race petrol engines can be ...
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