Why are single-cylinder diesel eWhy are single-cylinder diesel engines prone to reverse rotation?ngines prone to reverse rotation?

Single-cylinder diesel engines are prone to reverse rotation, which can easily cause injuries. Below are some reasons why single-cylinder diesel engines may reverse rotation; operators should take precautions.

1. Improper starting: When starting a diesel engine by hand, improper force can cause the piston to rotate backward under the pressure of compressed gas before passing the top dead center of the compression stroke when the decompression lever is lowered. Under the action of the flywheel, the piston will rotate backward past the top dead center, causing reverse rotation.

2. Incomplete engine shutdown: When the fuel injection is set too high or the throttle return spring is weak, releasing the throttle lever will not shut off the engine completely. The speed control lever must be manually lifted to stop the fuel injection pump. When the fuel injection stops, the crankshaft continues to rotate due to the flywheel's inertia. When the inertial force is less than the cylinder pressure, the piston cannot pass the compression top dead center and instead moves downwards under gas pressure, causing the crankshaft to reverse. If the speed control lever has been released at this time, the fuel injection pump will supply some fuel, causing the diesel engine to reverse and ignite.

3. Premature fuel injection: When the fuel injection timing is too early, the air-fuel mixture will burn prematurely, generating significant pressure that pushes the upward-moving piston back, causing the crankshaft to reverse.

4. Overload: Due to diesel engine overload, when decelerating to the point of near shutdown, the flywheel speed approaches or equals 0, while the piston moves upwards within the fuel injection angle range. If the clutch is disengaged at this time, the diesel engine overheats, causing the fuel injected into the cylinder to burn rapidly, pushing the piston, which has not yet passed top dead center, downwards and causing it to reverse.

5. Slippage: If the tractor stalls while climbing a slope and the clutch is not disengaged or the gear is not shifted, slippage will occur, causing the drive wheels to reverse the diesel engine through the transmission mechanism.

6. Flywheel key rolling: Severe key rolling on the flywheel and breakage of the keyway can cause timing errors and lead to diesel engine reversal.