Coking on the piston caused the problem

Piston common fault is damaged, ablation, wear and tear. Pistons are fragile parts, the price is cheaper, the general maintenance of agricultural machinery in the piston is not repaired, but directly replaced. However, before the replacement of new items, should identify the cause of the piston damage, and the reasons for the piston damage analysis, so as to avoid the same failure again.

      The carbon deposit on the piston is mainly deposited on the piston crown. Since the fuel and oil entering the combustion chamber often can not be completely combusted, carbon deposition occurs at the top of the piston and at the annular groove. If the piston at the top of a serious carbon deposition, easy to cause hot ignition, the engine cylinder abnormal combustion; if the ring groove serious carbon deposition, piston ring easy to snap in the ring groove, resulting in decreased cylinder sealing performance, it should be regularly removed Pistons and cylinder carbon deposition. The top of the piston carbon scraper can be removed. If there is carbon in the piston ring groove, the broken old piston ring can be ground into a suitable shape for removal, but care should be taken not to scratch the bottom of the piston ring groove. Can also be used to clear the chemical method, about the serious carbon deposition of the piston into the decarbonization solution soak 2 ~ 3 min, the solution temperature was maintained at 80 ~ 95 ℃. After removing the piston with a brush or cotton to remove carbon deposition, and finally with 0.1% to 2.3% potassium dichromate in hot water wash and dry.

Pistons should be checked after the demolition of the top of its anomalies, if the obvious impact caused by the dent or crack, should promptly identify the cause of the malfunction, to be ruled out. Engine work, resulting in damage to the piston by the impact is generally the valve clearance is too small, with the gas phase inaccurate, the valve spring break and other causes piston and valve collision, or maintenance of foreign objects into the cylinder. Damage to the piston, if the top of the depression, but no crack can continue to use, if there are cracks or holes must be replaced with new pieces. Broken piston should be replaced with new parts.

      The main role of the piston is to withstand the combustion pressure in the cylinder, and this force is transmitted to the crankshaft via the piston pin and connecting rod. In addition, the piston also with the cylinder head, cylinder wall together constitute the combustion chamber.

      Piston top is part of the combustion chamber, which often made into different shapes, the top of the petrol piston flat top or concave top, in order to make the combustion chamber compact, small heat dissipation, the manufacturing process is simple. The crown piston is commonly used in two-stroke gasoline engine. Diesel piston top often made into a variety of pits.

      The piston head is above the piston pin seat, piston head piston ring installed to prevent high temperature and high pressure gas fleeing into the crankcase, while preventing oil from fleeing into the combustion chamber; most of the piston top of the absorption of heat through the piston head Department passed to the cylinder, and then passed away through the cooling medium.