What does negative pressure flashback mean?
1 Answers
Negative pressure flashback occurs when the flow velocity of the air-fuel mixture from the gas nozzle is lower than the flame propagation speed, causing the flame to retreat into the burner for combustion. To prevent flashback, factors that may increase flame propagation speed or reduce mixture ejection velocity must be addressed. Below is relevant information about flashback: 1. Overview: Engine flashback refers to the premature combustion of the air-fuel mixture before it enters the combustion chamber. This is typically caused by incorrect ignition timing, poor engine conditions leading to excessive cylinder temperatures, or inadequate valve sealing. 2. Causes: When the throttle is rapidly opened, a large volume of air flows through the carburetor at high speed. Since gasoline has poorer fluidity than air, it cannot be ejected from the nozzle promptly enough to mix with the air, resulting in a leaner mixture. The lean mixture burns slower than normal in the cylinder, continuing to burn until the end of the exhaust stroke and the start of the intake stroke, thereby igniting the fresh mixture and causing carburetor flashback.