判断发动机的几种声音(Judge the several sounds of the engine)

---------------------------------------------------------------最新资料推荐------------------------------------------------------判断发动机的几种声音（Judge the severalsounds of the engine）判断发动机的几种声音（Judge the several sounds of the engine） This paper simply introduces the characteristics of the engine’s various noise, the reason of failure and the method of checking and troubleshooting, for reference: The abnormal sound of cylinder, piston and piston ring. 1. Impact of piston top and cylinder cover. (1) the characteristics of the sound. The voice of the collision cylinder cover is in when the engine is running between the cylinder and the cylinder cover parts, continuous and clear dangdang metal tapping sound is strong, and the cylinder cover with some vibration. (2) cause of failure. A. The crankshaft bearing connecting rod bearing or bearing and the piston pin hole are severely worn and loose, and the piston top will impact the valve cover in a moment when the piston is traveling at the speed of the stroke.B. May also be due to the manufacture of quality reasons or the use of accessories that do not support the piston to reach the upper end of the high and collision valve cover. (3) the elimination method. Remove the cylinder head, check the status of collision and can change depending on the situation1 / 7of qualified products and supporting parts, can also add a suitable cylinder liner, cylinder cover increases without collision, and if relevant a serious wear and tear, and shall repair or replace the worn parts. 2. Collision of piston top and valve door: (1) characteristics of sound: The failure phenomenon occurs only on the overhead valve engine, in the collision in the upper cylinder and the cylinder cover can be heard a rhythm, interval of when, when metallic sound, engine speed increased, the noise is more serious. (2) cause of failure: A, on the rocker arm adjusting bolt to tighten the lock nut, by vibration after the change in the normal work, cause smaller valve clearance and resist valve rod end, on the exhaust stroke piston to check point is, touching the valve head, or the timing chain wheel assembly is not on the tag. B. The size of the valve rod and the valve catheter is not well matched. After the heat expansion of the metal, there is a stagnation phenomenon, or the material meets the requirements of excessive expansion coefficient. (3) failure judgment and exclusion. The first thing to determine is which valve is colliding, its method: remove the valve cover, contact with the swing arm or hold the rocker arm, and tap the start lever. If the rocker arm has a noticeable vibration or arm touch, then it can be judged---------------------------------------------------------------最新资料推荐------------------------------------------------------ that the valve has a collision phenomenon. The reason or readjustment should be determined at this time to meet the requirements and then lock the nut. B. Check the assembly mark of the timing sprocket and flywheel. C, for other reasons, to repair or replace the relevant unsuited parts. Iii. Abnormal sound of piston rings; (1) metal tapping at the plug ring. A, when the piston ring is broken or the gap between piston ring and piston ring is too large. After b, the upper cylinder wear, piston ring and cylinder out of reach of almost no wear and tear on the formation of the steps, such as improper repair causes the piston ring and cylinder into steps will make a pure dumb poof, poof clattering metal sound, with the increase of rotational speed, noise also will increase (2) the ring of piston rings: A, reasons and characteristics: piston ring elastic weakened the piston ring and cylinder wall Sealing is lax, the piston ring opening gap is too big or opening overlap, cylinder wall, such as scratch slotted piston ring can cause leakage. There will be an empty drink, drink or squeak, squeak sound. There is a noticeable poop-poop sound. B. The method of failure inspection: inject a little bit of lube into the cylinder. If the sound is reduced or disappeared, it will appear3 / 7soon, which means that the piston ring leaks (3) there is too much carbon in the piston ring A, the characteristics of the sound: the sound of excessive accumulation of carbon, is a sharp pestle, peep The sound, the engine, sometimes i t’s not easy to stall. B, the formation causes, the main reason is the piston ring and cylinder wall, untight seal opening gap is big, piston rings installed backwards, opens the mouth to overlap, the lubricating oil into the combustion chamber, or gasoline label does not meet the requirements, a rich mixture, air filter is too dirty cause. Iv. Valve mechanism: Valve leakage: (1) in the exhaust muffler parts, such as heard a voice of hey, hey, the representation of a sound engine exhaust valve of leak phenomenon, and in the carburetor air cleaner upper side heard a SHH, SHH sound, indicates the engine inlet valve of leak phenomenon, of the valve leakage reasons are: A, valve and valve seat work inclined surface wear, ablation, produce spots or sag, have carbon. B. The gap between the valve rod and valve tube is too large, the valve stem is wobbly, or the valve stem is bent, and the valve head is skewed, causing the valve to be closed. A. The spring force of the valve spring decreases and loses elasticity, or the spring breaks There is no close cooperation between the valve and the valve seat. B. The valve---------------------------------------------------------------最新资料推荐------------------------------------------------------ space is small, the valve rod is heated and expanded, the tappet and rocker open the valve, so that the valve can not completely close and leak. Elimination method: according to the actual situation, check the failure, repair or replace the related wear and damage accessories. (2) the noise of adjusting the bolt of the valve stem and the bolt. Features: the noise of da or dia or dia with the existing rhythm at idle speed increases with the speed, and the sound increases and gets cluttered. Cause: improper adjustment of valve clearance. Rule out: after engine lift, preheat for 3-5 minutes, re-check or adjust valve clearance. 5. Tapping sound: Characteristics: (1) the sound is refers to the piston type cylinder at the beginning of the working stroke, the piston within the cylinder, its head and skirt and cylinder wall collision is the sound of noise of main parts in the cylinder body is clear sharp dang, dang or click, tower sound. (2) the cause of the failure: A, when the cold car starts, because the piston is cold shrink and the space between the cylinder wall is larger, there will be a slight knock, as the temperature rise the sound will be reduced to disappear. B. When starting the engine, the lubricating oil pressure is low due to the poor lubrication condition, and the5 / 7lubricating oil on the cylinder wall does not form the oil film, and the piston is directly touched with the cylinder body. When preheating for 3 ~ 5 minutes, the lube normal sound will also decrease and disappear. C. The gasoline label does not meet the requirements, and the mixture can not burn normally, resulting in premature combustion or detonation, causing the forced piston to collide with the wall of the cylinder. D, when the engine is in heavy load, such as climbing, sinking into a mud hole, and the door of high speed, etc., will produce the cylinder. F, piston skirt is worn, the actual error of cylinder is too large, and the piston head hits the cylinder wall while the piston is traveling. G, after long-term use of engine, the piston and cylinder wear, the gap between each other, at the beginning of the working stroke, the piston within the cylinder of swing, caused the skirt touch attack type cylinder cylinder wall. H, connecting rod bend or twist, piston pin and piston hole, connecting rod bearing and crank pin can not cooperate properly, can also cause piston deflecting cylinder.(3) analysis of fault judgment: If it is a when, when sound, as if with a hammer to knock the voice of the steel pipe, usually caused by poor lubrication cylinder wall, then can add a little oil inside the cylinder, then start the engine, the change of---------------------------------------------------------------最新资料推荐------------------------------------------------------ observation noise, reduce or disappear if voice, suggests that fault is caused by poor lubrication. B if there is a da or tower sound, or a blue smoke with oil exhaust pipe, it is usually caused by excessive clearance between piston and cylinder wall. Due to the manufacturing aspect, the piston and the cylinder body are not in good coordination with each other. When the piston is in motion, the hem of the skirt is unstable and can cause noise. (4) troubleshooting: Knocking reason belongs to a, b two, can start on a few times more before start lever, preheating 3 ~ 5 minutes after launch, so that the lubricant adhesion on the moving parts and make the engine a little heat, forming a certain amount of oil film in order to reduce the amount of wear parts, belong to c reasons, should maintain the engine working in normal temperature, clean the carbon deposit in cylinder, conform to the requirements of the octane number of gasoline. If it belongs to f, g or h, it shall be checked and repaired separately7 / 7。