i know the bigger the capacity the better the horsepower and torque ouput but what does the litre bit mean? i hope you understand my question
It's how much space there are inside the cylinders where the pistons are, check wikipedia on how the four stroke engine works.
Just ask if you need more explanation, then I'll find my dictionary
The engine is made up of a number of cylinders. In the cylinder the piston moves up and down accordingly to the stroke.
In a normal four stroke engine there are 4 strokes happening in the cylinders: Intake, where air and waporized fuel is sucked in the cylinder through the walves; compression, where the mixture is compressed; combustion, where the sparkplug ignites the mixture (this is the stroke that creates power); exaust, where the exaust is pushed out of the cylinder.
In an engine with 4 cylinders each cylinder does a different stroke at any given time.
When the engine does one rotation there has happend 2 strokes.
The pistons are connected to a crankshaft that transforms the up/down motion to a rotation, that is the thing that makes the car move.
The litre number is the combined volume of all the cylinders in the engine.
The thing I wrote? It's from my head
I think it's a combination of things, like a 2 litre 1 cylinder engine wouldn't have as much power as a 2 litre 4 cylinder engine because it would loose some power in the 3 strokes when it isn't producing power. Did that make senceOriginally Posted by jensked
The bigger the cylinders are, the more fuel and air you can inject. So you have a greater combustion. Therefore, when you have bigger cylinders you have more torque (with the same engine that is). It's not only the displacement that determines the amount of torque (hp is dirived from torque, and torque is the more important figure) though (difficult matter).Originally Posted by jensked
Ok, very basic explanation. In a bigger engine bigger explotions of fuel can happen. Bigger explotions = More power. There is ofcourse, as you can see on the data sheets more to it than that. For example how precise the engine can handle the combustion and so on. The explotions can be made more powerful by adding more air to it with turbos and superchargers or compressors.
Another way to increase HP is to increase what's called the "compression ratio" of the engine.
The "compression ratio" of an engine is basically how much it compresses the air/fuel mixture before combustion.
Let's say you have a 8L V8 engine. That means that each cylinder's combustion chamber is 1L in size at the bottom of the piston stroke (aka Bottom Dead Center). Now, if the piston moves upwards to the top of its stroke (Top Dead Center) and the size of the combustion chamber has been reduced to 0.1L, you can say that the engine has 10:1 compression, as the compressed mixture is one tenth the size of the uncompressed mixture.
Most engines run about 8-9:1 compression, but the more compression you run, the more power you get from the same amount of air&fuel. However, high compression is very hard on engines and can lead to detonation.
Girl.....checkOriginally Posted by mgkdk
Knows about cars....check
[Kneeling] Would you marry me?
However, detonation -- or knocking -- can be circumvented by running higher grades of gasoline. The grades or ratings of gasoline are a referance to the ability of the gasoline to not prematurely detonate when compressed. That's why high end sports cars require high end fuel. If you were to put 87 into a Ferrari, you'll probably end up with a $200,000 paperweight...Originally Posted by BerserkerCatSplat
Yes, Beserker, I realize you probably already know this, but this is more for the education of others who are unfimilar with auto termanology...
this is written in the explanation of the veyron on howstuffworks.com, i taught it explained quite clearly how they got 1000hp out of petrol, and how hard it actually is, and also explains jensked's question
* 1,000 horsepower is equivalent to roughly 2.6 billion joules per hour. A gallon (3.8 liters) of gasoline contains 132 million joules, so a 1,000-hp engine has to be able to burn just over 20 gallons of gasoline per hour.
* However, car engines are only about one-quarter efficient -- three quarters of the gasoline's energy escapes as heat rather than as power to the wheels. So the engine actually has to be able to burn at least 80 gallons per hour, or 1.33 gallons (5 liters) per minute.
* Let's convert over to metric. Gasoline requires about 14.7 kilograms of air to burn 1 kilogram of gas. Air weighs 1.222 kilograms per cubic meter at sea level. A gallon of gasoline weighs 2.84 kilograms. So the engine has to be able to process 2.84*1.33*14.7 kilograms of air per minute, or roughly 45 cubic meters of air per minute. That's 45,000 liters of air per minute.
* If a V-8 engine is turning at 6,000 rpm, it can inhale a total of 24,000 cylinders' full of air per minute. If it needs to inhale 45,000 liters of air per minute, it works out to roughly 2 liters per cylinder-full. That's a 16-liter engine.
We need a 16-liter engine to burn 1.33 gallons of gas per minute. That actually makes sense -- the engine in the Dodge Viper is 8.0 liters in displacement and produces 500 hp.
That's how Honda managed to squeeze 160 HP out of the 1.6L in my car...10.2:1 ratio. And that's also why I put at least 91 octane in my car.Originally Posted by YF19pilot
You know, maybe we should sticky this thread and direct people who are unfamiliar with automobiles and their workings to this thread, sort of like an unofficial faq about cars.
there have already been a few threads about that madeOriginally Posted by YF19pilot
i tried to explain superchargers: http://forum.finalgear.com/viewtopic...760&highlight=
i had a question about diesel engines, and later found a super read about them: http://forum.finalgear.com/viewtopic...747&highlight=
a superb read about rotory engines: http://forum.finalgear.com/viewtopic...265&highlight=
a thread about a 6 stroke engine (and some others): http://forum.finalgear.com/viewtopic...268&highlight=
josty explaining turbos: http://forum.finalgear.com/viewtopic...744&highlight=
josty had a question about diffs, and i tried to explain (agian): http://forum.finalgear.com/viewtopic...900&highlight=
we need more discussions in this direction
much more interested in stuff like this than what brand released which car
Don't worry, I do know that - but this thread is for the benefit of the people that don't. Thus, I'm sure your input is valuable to them.Originally Posted by YF19pilot
Originally Posted by bone
You know, I think I'll start like a weekly technology discussion. Like "Cars 101" something that'll be beneficial to this site and that I can also have in my blog/magazine thing, and also give people something to read and discuss in the Q&A forums. I'll note your links and this one in the bottom for people to referance.
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