Defensive driving site - your source of information and the place to share your experience
 Home    Save Gas    Forums    Encyclopedia    Articles    Polls    Videos    
Our Videos

Most Viewed Video How
How to sit properly while driving - Low Res

Latest Video Driving
Driving around slippery corner in Croatia

Highest Rated Video Driving
Driving in Moscow

 
Main Menu
· Home
· Articles
· Driving Links
· Encyclopedia
· Forums
· Highway Surveys
· Mapquest Driving Directions
· Video Library
 
Drivers Info
Welcome, Anonymous
Nickname
Password
(Register)
Drivers Online:
Visitors: 35
Member Drivers: 0
Total: 35
 

Detonation




Detonation is one of the forms of abnormal combustion. It is an uncontrolled explosion, and its speeds are 10s if not 100s times faster than any normal fuel burning speed. In fact, the speeds are supersonic, and that is what makes detonation dangerous to your engine. The difference between gas oven normal burning and its explosion can give you an idea of the difference between normal combustion in an engine and detonation. Another analogy would be the difference between a gunshot and a mine burst.

Detonation happens when fuel octane rating is not sufficient for current combustion chamber conditions due to either incorrect fuel used, or excessive deposits build-up (which increases compression ratio), or, sometimes, too early ignition timing. All those things can work in concert, of course. Due to the combination of those reasons, at the end of the compression cycle air/fuel mixture gets heated too close to the temperature of its self-ignition. After spark plug ignites the initial portion of mixture, and flame front starts to propagate towards the rest of combustion chamber, pressure increases at a high rate all over the volume of the combustion chamber, causing the remaining mixture to quickly heat up beyond its self-ignition threshold. As soon as this threshold is surpassed in some point, another center of ignition is born, which produces another flame front. Those fronts work together to increase the pressure and temperatures even more, producing more ignition points. This chain reaction leads to explosive increase in pressure growth rate, which produces a shock wave, resonating all over the combustion chamber. On the outside of the engine detonation reveals itself as a high pitch metallic knocks or pings at heavy load and relatively low rpms.

Since detonation is a real explosion, it can damage your engine fairly quickly and therefore should be avoided. If you use manufacturer’s recommended gas and still hear detonation, you need to have your car checked and/or serviced ASAP. Modern cars with computer-controlled engines do have knock sensor and computer retards ignition timing to avoid detonation, if necessary. This significantly hurts your mileage, however, because your engine no longer utilizes optimal ignition timing.




[ Go Back ]

Fun and Safe Driving Encyclopedia

Copyright © by Fun and Safe Driving - (16606 reads)

Encyclopedia ©
Highway Survey
Who has the right of way at a four way stop?

Me!!!
Whoever can get through first - probably me... GO!
Four way... what is a four way?
First in... first out I always say.



Results
Polls

Votes: 4181
Comments: 4
 
Traffic Stories
· Thought driving on Manhattan is nuts? Think again. (1 reply)
· Changing gears - How - Part2 of how to drive a stick shift (11 replies)
· This is some nice winter driving (2 replies)
· How to drive a stick shift - part1 - basic starting (11 replies)
· Weaving in and out of traffic while driving – just how bad is it? (47 replies)
· Driving how fast is too fast? And driving how fast is still safe? (21 reply)
· trucks are better for driving in wintery conditions (16 replies)
· Driving mistakes (14 replies)
· Fuel filter line loosening (5 replies)
· What computer do you have? (20 replies)
· OK... what actually got me thinking that I should be more carefull (3 replies)
· My second car (1 reply)
· My wife got a ticket while driving yesterday (12 replies)
· Winter driving tips - tip#2 (3 replies)
· My third car (4 replies)
· Is Universe laughing at you? (18 replies)
· My first car (33 replies)
· Crazy gas saving devices (2 replies)
· Sweet revenge (31 reply)
· Ask Misha about Cars - new forum started (0 replies)
· Winter driving tips - tip#1 (2 replies)
· Safe speed (19 replies)
· You should change your oil every 3000 miles - or should you? (14 replies)
· Fogged windows (4 replies)
· Driving in the right lane trick (10 replies)
· Mods I do to my cars (24 replies)
· Driving AWD (4WD) is safer (19 replies)
· Do you trust your mechanic? (11 replies)
· manual tranny myth #2 (30 replies)
· I own my dream car (15 replies)
 
Random Topic

My Car
[ My Car ]

·My second car
·My third car
·My first car
·Mice nest
 
 
Defensive Driving | Contact us | Privacy policy | Terms of Use | Texas Defensive Driving
Forums RSS Feed
NJ Defensive Driving | New York Defensive Driving| Fuel Economy



Page Generation: 0.06 Seconds
Fun and Safe Driving © 2006-2024