23

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 between 600RPM to 1000RPM, signifies the speed of the crankshaft. The fuel is calculated by the ECU (or ECM or PCM) depending upon the load, which is a calculated ...


12

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 kills the engine when it's not needed, but that's usually after several seconds of sitting still, as long as other parameters are met as well. Most vehicles ...


10

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 use hexane as fuel. To burn one hexane molecule consisting of 6 carbon and 14 hydrogen atoms, we need 13 oxygen atoms (6.5 oxygen molecules) and get 7 water ...


6

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 revolutions per minute (RPM) = 10 revolutions per second (RPS). Assuming this is a 4 cycle engine, so 2 revolutions per cycle, so 5 complete cycles per second. Each ...


5

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 water, which is fine. There are several vehicles and several vehicle companies which have explored the concept of pure hydrogen as a combustible fuel. The ...


5

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 pedal. In an automatic vehicle, a torque converter essentially does the same thing as a clutch, but does not require manual intervention. These mechanisms ...


5

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. In an internal combustion engine, chemical energy is converted directly to mechanical energy in the form of expanding gas combustion products. Conversely in a ...


4

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. When in the engine, fuel is disbursed into droplets which creates a lot of surface area for the fuel to expel vapor. What the ECU does is create a very ...


4

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 combustion engines are a type of heat engine where the heat is produced (by combustion - burning) outside of the engine itself. From the wikipedia page: An ...


4

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: The rotor seals off the air/fuel intake charge from the intake port, gradually compressing it until it is sufficiently compressed, at which point the spark plug ...


3

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 could be switched from gasoline to hydrogen. The difference in fuel consumption is largely due to the different energy density with gasoline (petrol) yielding ...


3

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 common, say the last 3-5 years, across all K-cars (multiple manufacturers). On these cars, this StopStart feature is also available on automatic cars, so the ...


3

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 west coast. They also powered paddle wheel boats up the Mississippi and allowed for powered crossings of the Atlantic Ocean. But enough of the history lesson. ...


3

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, with some from biomass gasification. A tiny amount is produced by electrolysis of water (but it uses a lot of power to do so) So, yes, you can use anything ...


3

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 batteries and 30 times lower than petrol or diesel. So compressed air cars have short range. They're also harder to refuel than an electric car. This combination means ...


2

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, would take a huge amount of energy. So they question isn't so much why can't they, but where would that energy come from? The energy in a standard internal ...


2

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 necessarily get to do that. For example some aircraft engines are designed to run with an excess of fuel at high power in order to provide additional cooling, the "...


2

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 between the exhaust cycle and the intake cycle. Valve overlap will only allow exhaust gasses to revert (called reversion) back into the combustion chamber during ...


2

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: TDC - Top dead center - as the piston is traveling upwards in the cylinder BDC - Bottom dead center - as the piston is traveling downwards in the cylinder After ...


1

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 between the total volume (swept + clearance) and the clearance volume is the compression ratio - around 7 to 12 : 1 for gas / petrol engines and 18 to 24 : 1 for ...


1

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 atmospheric pressure is forced into the inlet manifold alongside additional fuel to keep the mixture at circa 14:1. Higher pressure turbo systems pair the ...


1

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 mention lower performance. In a diesel you will have carbon deposits and on ones with catalytic converters you can fowl them. you can ensure more fuel burns by ...


1

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. After doing more captures on different cars with VVT I've found that most waveforms are unique to some degree. I guess the same can be said about non VVT ...


1

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 energy as heat losses makes little sense. This is why most hydrogen vehicles use fuel cells. Their higher efficiency (up to 60%) combined with the high ...


1

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 higher at more than 105Atm's


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