cylinder head introduce

The cylinder head is installed on top of the cylinder block, sealing the cylinder from the top and forming the combustion chamber. It often comes into contact with high-temperature and high-pressure gas, so it bears a large thermal and mechanical load. The cylinder head of a water-cooled engine is equipped with a cooling water jacket, and the cooling water hole on the lower end face of the cylinder head is connected to the cooling water hole of the cylinder block. Circulating water is used to cool the high-temperature parts of the combustion chamber. The cylinder head is also equipped with inlet and exhaust valve seats, valve guide holes, and is used to install inlet and exhaust valves, There are also intake and exhaust channels. The cylinder head of gasoline engines is equipped with holes for installing spark plugs, while the cylinder head of diesel engines is equipped with holes for installing fuel injectors. The cylinder head of overhead camshaft engines is also equipped with camshaft bearing holes for installing camshafts. The cylinder head is generally made of gray cast iron or alloy cast iron, and aluminum alloy has good thermal conductivity, which is conducive to improving compression ratio. The cylinder head is an integral part of the combustion chamber, The shape of the combustion chamber has a significant impact on the operation of the engine. Due to the different combustion methods of gasoline and diesel engines, there is a significant difference in the parts that make up the combustion chamber on the cylinder head. The combustion chamber of gasoline engines is mainly on the cylinder head, while the combustion chamber of diesel engines is mainly on the concave pit at the top of the piston. 1. The cylinder head bolts should be tightened evenly and the fuel supply time should be adjusted correctly. 2. Soft water should be added to the water tank, And try to change water as little as possible. 3. The engine should avoid working under overload for a long time. 4. When the engine is working and the water tank occasionally runs out of water, do not immediately turn off the engine. Instead, slowly add water at low speed. Do not add cold water after the engine heats up. After parking, wait for the water temperature to below 40 ℃ before adding water. In cold winter, do not add water immediately when starting, Instead, heat the water first and add boiling water. During assembly, check whether each cooling water hole is unobstructed. Regularly clean the cooling system with alkaline solution and promptly remove scale and oil stains [1])

The installation steps for the cylinder head are as follows:

The installation steps of the cylinder head are as follows: The installation of the cylinder head should be carried out in the order of disassembly first and then installation, and the following issues should be noted during the assembly process: 01 Before installing the cylinder head, the crankshaft should be turned to the top dead center position of the first cylinder. 02 When installing the cylinder head gasket, the side marked with the part number must be visible. 03 Replace the cylinder head fastening bolts, Do not reuse bolts that have been tightened according to the tightening torque. 04 Tighten the cylinder head bolts to a torque of 40N · m in the sequence shown in the following figure, and then use a wrench to tighten 180 °. Tighten the cylinder head bolts to a torque of 40N · m in the sequence shown in the figure. 05 Install the timing belt (adjust the valve timing phase), install the valve cover. 06 Adjust the throttle lock, Add new coolant. 07 Perform throttle control unit matching. 08 Query fault codes. Removing the electronic component plug of the electronic control unit will cause fault storage. Query fault codes and delete them if necessary. 09 Pay attention to the tightening torque of the main component bolts. The tightening torque of the front exhaust pipe and exhaust manifold fastening bolts is 20N · m, and the tightening torque of the fastening bolt between the intake manifold bracket and the engine is 20N · m, The tightening torque of the fastening bolts between the intake manifold bracket and intake manifold is 30N · m

Audi A4L introduce

The Audi A4L is an entry-level luxury B-class sedan produced by FAW Audi. The characteristics of this car are its atmospheric and stable body, meticulous workmanship, solid materials, rich configuration, spacious space, and good handling A4L was officially released on November 16, 2008, and the front face design of the new Audi A4L continues to use the family's expensive sports car design style. The price range of Audi A4L is 272800-578100. The domestic version of the new generation Audi A4 was officially named: Audi A4L. Audi A4L is a new car that Audi only launched in the Chinese Mainland market. The relationship between the new car and A6 and A6L is similar, and it is also after foreign models are made in mainland China, A model derived from changes in configuration and market demand. After higher level mid to high end luxury cars have chosen to be lengthened in China and received good market feedback, this idea is now extending to its lower level mid size car market. Compared with the European version of the Audi A4, the domestic version of the Audi A4L has lengthened the body length by 60mm, reaching 4763mm, and the wheelbase has been lengthened by 61mm, reaching 2869mm, Satisfying the higher requirements of Chinese users for rear passenger space