What Causes Excessive Under-Exhaust in Diesel Vehicles?
1 Answers
Excessive under-exhaust in diesel vehicles can be caused by the following reasons: 1. Severe wear of the engine's piston rings and cylinder liners: Piston top erosion or cylinder scoring. If the piston rings and cylinder liners are severely worn, or if there is piston top erosion or cylinder scoring, the seal between the piston rings and cylinder liners becomes compromised. During the compression and expansion processes of the diesel engine, a large amount of compressed gas can enter the crankcase through the tiny gaps between the piston rings and cylinder liners, leading to increased crankcase exhaust pressure. The main symptoms include severe under-exhaust from the breather, insufficient engine power, and possibly blue smoke emission. 2. Incorrect installation of engine piston rings: Misaligned piston ring gaps. If the piston rings are installed incorrectly with all gaps aligned, even if the piston rings are not worn, a significant amount of high-pressure gas from the compression and expansion processes will enter the crankcase, causing increased crankcase exhaust pressure. Alternatively, piston rings may stick, break, or lose elasticity, all of which will result in poor cylinder sealing, allowing combustion gases to leak into the crankcase and significantly increasing crankcase exhaust pressure.
