Freddie's Buick
Hell No! I'm not a junior
- Joined
- Jan 3, 2002
Here's some stuff I learned about detonation and our Regal's EGR valves. (If any of this is incorrect, feel free to let me know).
1) Detonation is is an erratic form of combustion. Detonation occurs when excessive heat and pressure in the combustion chamber causes the air/fuel mixture to auto-ignite. This produces multiple flame fronts within the combustion chamber instead of a single flame kernel.
When these multiple flames collide, they do so with such an explosive force that it produces a sudden rise in cylinder pressure. This results in a sharp metallic pinging or knocking noise. The hammer-like shock waves created by detonation subject the head gasket, piston, rings, spark plug and rod bearings to severe overloading.
2) The Exhaust Gas Recirculation (EGR) system leaks small amounts of exhaust into the intake manifold through an EGR valve. Though these EGR gases are hot, they actually have a cooling effect on combustion temperatures by diluting the air/fuel mixture slightly. As well as reduced formations of NOX for emissions control, this results in a smooth controlled burn that prevents detonation.
Detonation happened to my Regal when I used the wrong EGR valve. The lesson I learned I share with this forum. Although all our EGR's look alike, they are not. The type of EGR my N/A uses is in the following pics:
http://members.telocity.com/~familiadiaz/EGR Diagram.jpg
http://members.telocity.com/~familiadiaz/internal EGR.jpg
1) Detonation is is an erratic form of combustion. Detonation occurs when excessive heat and pressure in the combustion chamber causes the air/fuel mixture to auto-ignite. This produces multiple flame fronts within the combustion chamber instead of a single flame kernel.
When these multiple flames collide, they do so with such an explosive force that it produces a sudden rise in cylinder pressure. This results in a sharp metallic pinging or knocking noise. The hammer-like shock waves created by detonation subject the head gasket, piston, rings, spark plug and rod bearings to severe overloading.
2) The Exhaust Gas Recirculation (EGR) system leaks small amounts of exhaust into the intake manifold through an EGR valve. Though these EGR gases are hot, they actually have a cooling effect on combustion temperatures by diluting the air/fuel mixture slightly. As well as reduced formations of NOX for emissions control, this results in a smooth controlled burn that prevents detonation.
Detonation happened to my Regal when I used the wrong EGR valve. The lesson I learned I share with this forum. Although all our EGR's look alike, they are not. The type of EGR my N/A uses is in the following pics:
http://members.telocity.com/~familiadiaz/EGR Diagram.jpg
http://members.telocity.com/~familiadiaz/internal EGR.jpg
