radarbeam
Posts: 998
Joined: Fri Mar 01, 2002 9:00 am

Engine Terminology

Sun Apr 14, 2002 5:27 am

A quick question for you,

Lately, I've been wondering what the 2.0 litres or 2.2 litres means when refering to an engine. For example my engine is a 2.0L DOHC 150HP.

Thanks,

Radarbeam
 
saintsman
Posts: 2037
Joined: Fri Mar 15, 2002 12:34 am

RE: Engine Terminology

Sun Apr 14, 2002 5:47 am

2.0 liters - The capacity of the cylinders in the engine.

DOHC - Double overhead camshaft . This is the device that lets the valves move which lets the fuel in and the exhaust out. And there are two of them.

150HP - The engine creates the equivalent power that would take 150 horses to generate.
 
Adam84
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Joined: Sat Jul 24, 1999 6:10 pm

RE: Engine Terminology

Sun Apr 14, 2002 5:50 am

Its the displacement. The amount of empty space in all your cylinders when they are at the bottom of their stroke.

 
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aerorobnz
Posts: 7412
Joined: Sat Feb 10, 2001 3:43 pm

RE: Engine Terminology

Sun Apr 14, 2002 6:04 am

2000 cubic centimetres or the nearest displacement to it...eg 1998cc
in general a bigger naturally aspirated engine can produce more power...but there are always exceptions..
Flown to 120 Airports in 44 Countries on 73 Operators. Visited 55 Countries and counting. Wanderlust is like Syphilis, once you have the itch it's too late for treatment.
 
flyf15
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Joined: Tue May 18, 1999 11:10 am

RE: Engine Terminology

Sun Apr 14, 2002 6:32 am

You may also hear displacement written as cubic inches. About 61 cubic inches = 1 liter. So, you engine is also about 122 cubic inches.
 
Illini_152
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Joined: Sun Jan 14, 2001 6:00 am

RE: Engine Terminology

Sun Apr 14, 2002 7:56 am

And if you want to get real technical, displacement is the bore * stroke * # of cylinders. Bore is the inside diameter of the cylinder, and stroke is the distance that the piston travels during one revolution. A larger engine will produce more torque for a given RPM, but there are ways to get more power out of a small normally asperated engine. These generally involve winding them to a real high RPM.

Indy cars manage 800hp out of a 1.9L engine. Of course, they're turbocharged and running on pure ethenol. And turning at around 14,000 rpm.

Interestingly, horsepower is a fabricated number that Watt came up with based on how much coal he thought a mine Mule could haul in a givin time- 33,000 lb-ft/minute. An interesting site for questions like this is How Stuff Works-

http://www.howstuffworks.com/horsepower.htm
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FordLover
Posts: 189
Joined: Wed Sep 26, 2001 3:12 am

RE: Engine Terminology

Sun Apr 14, 2002 11:44 am

Not quite right Illini_152, you left out pi. Displacement is a volume, so the formula is ((1/2 bore)squared x pi) x stroke x number of cylinders. And the more, the merrier!  Big thumbs up
 
NKP S2
Posts: 1665
Joined: Mon Dec 20, 1999 3:16 am

RE: Engine Terminology

Sun Apr 14, 2002 5:03 pm

Righto 'Fordlover' on the displacement calcultion...and I agree there's no replacement for displacement- in a pragmatic sense anyway. It should be noted that advertised Horsepower and Torque specs do not always tell the full story- They're just a "snapshot" at the peak of a curve and may not be indicative of the shape of the curve and how much usable power is available in most driving conditions. Generally, an engine with a broader powerband will be more satisfying to drive than one with a more "peaky" powerband. As the old hotrod adage goes: "Horsepower sells cars - Torque wins races". Horespower IS torque...but it depends on how effectively it is applied.
 
Illini_152
Posts: 959
Joined: Sun Jan 14, 2001 6:00 am

RE: Engine Terminology

Mon Apr 15, 2002 3:10 am

Whoops- shows me to proofread these things before I post them; think one think, type another. Talk about the brain fart, I was thinking area x bore, and you are correct about the area being pi R^2.

Couldn't agree with you more about displacement; give me a P&W R4360 Wasp Major. he he he; biggest piston engine ever built. 28 cylinders, 5.75" bore, 6" stroke. Some put out as much as 4500 hp.
Happy contrails - I support B747Skipper and Jetguy
 
radarbeam
Posts: 998
Joined: Fri Mar 01, 2002 9:00 am

RE: Engine Terminology

Mon Apr 15, 2002 5:41 am

Thanks guys for all the infos

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