What is the Function and Purpose of Barring?
2 Answers
The function and purpose of barring are primarily to inspect the operational condition of a vehicle, ensuring its safety and extending its service life. Below are detailed explanations regarding barring: 1. Purpose of barring before starting the engine pump: Barring the engine pump checks for flexibility, any jamming, or abnormal noises inside, preventing damage to the pump or motor burnout due to excessive current during startup. For some large units, it also serves to warm up and lubricate before operation, avoiding localized overheating between the rotor and the body after startup, which could lead to body deformation. 2. Purpose of barring after shutting down the engine pump: For units that have just been shut down, barring is to prevent thermal deformation, usually requiring a short cooling period before re-barring. For units that are shut down for extended periods, regular barring is necessary to prevent shaft bending deformation or rotor jamming caused by the equipment transporting highly viscous media, typically barring 540 degrees each time. 3. Barring procedure: First, the oil circuit should be cut off, and the start signal cable disconnected. Then, open the indicator valve of each cylinder to blow out any moisture, oil, or impurities inside the piston. After confirming that the diesel engine has no issues, it can be started. Before starting the diesel engine, it is essential to inspect the oil circuit, water circuit, air circuit, and electrical circuit related to the diesel engine. If no problems are found, the diesel engine can be started.
Hand-cranking the engine essentially means manually turning the engine crankshaft by hand or with tools. Its primary purpose is to ensure the engine can still rotate normally and prevent seizure during startup. After decades of driving, I've found hand-cranking particularly necessary in winter or after prolonged vehicle storage. It helps check for internal corrosion or stuck components like pistons or bearings – you'll feel heavy resistance when cranking if these parts malfunction. This practice also protects the battery and starter motor, as attempting direct startup with a seized engine can drain the battery instantly (potentially damaging it) and easily burn out the starter. I always advise beginners to develop the hand-cranking habit – gently rocking the engine twice before starting can save significant repair costs and downtime. Think of it as giving your car a quick health check to ensure worry-free driving safety.
