Compression to gas

[hookersinker]

How much compression does it take to ignite gasoline in a motor?<br />Thank you!

 

[Rex]

Re: Compression to gas

A diesel is 20.5 to 25 to 1.<br />I do not know why you would even ask that ?.

 

[steelespike]

Re: Compression to gas

Hookersinker, In a diesel compression ignites the fuel.In a gasoline engine compression is aided by the spark to ignite the fuel mix.<br /> Generally 100 lbs of compression is considered the minimum to work effectively though a motor will operate ok on less.

 

[rwise]

Re: Compression to gas

hookersinker <br />most will run on 80 psi compression, though it may not be good.<br />Richard

 

[dmessy]

Re: Compression to gas

zero compression..gas will ignite at atmospheric pressure. Are you asking compression ratio? Anywhere from 6:1 on up to 10+:1.<br />Cylinder compession varies with the amount of piston clearance, # of rings, thier position, and end gap. These all wear out eventually causing "low compression".(or is it a hole in the piston? )<br /> Each new engine has a factory specified compression level it meets before being shipped.<br />Have to agree with the last 2 posters on minimum levels of compression for outboards not older than 20 years or so..

 

[Forktail]

Re: Compression to gas

"How much compression does it take to ignite gasoline in a motor? Thank you!"<br /><br />It depends on the engine design and many other factors such as....<br /><br />Compression ratio - higher compression ignites sooner.<br /><br />Air/fuel mixture - leaner mixture ignites sooner.<br /><br />Ambient temperatures - lower temperatures cause earlier fuel ignition.<br /><br />Running cylinder temperatures - higher cylinder temps cause earlier ignition.<br /><br />Altitude - lower altitude causes sooner ignition.<br /><br />Deposites in combustion chamber - more deposits cause earlier combustion.<br /><br />Fuel octane - higher octane causes slower ignition.<br /><br />2 or 4 stroke? 4-strokes can usually run higher compression ratios with lower cylinder temperatures and thus pre-ignite (detonate) less.<br /><br />Plus a bunch of other stuff like humidity, etc.<br /><br />And one more biggy unless you have a HCCI gasoline engine (no-spark, autoignition engine) which you don't....<br /><br />Spark advance or ignition timing.<br /><br />Remember, pressure is temperature affect each other.<br /><br />So....the compression needed to ignite fuel in your engine could be just about anything. Only the manufacturer knows what it must be.