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 Q7 introduce

The Audi Q7 is a full-size SUV that emphasizes comfort, cleverly integrating sportiness, functionality, high technology, and luxury quality. On the road, it stands out with its infinite dynamic handling and sporty characteristics; On off-road roads, its powerful driving force is even more impressive. Undoubtedly, the Audi Q7 is another groundbreaking masterpiece of the founder of quattro technology at Audi. The Audi Q7 is a luxury sedan produced by Audi, with two modes: racing and station wagon. Its main competitors include the Marseille Mercedes Benz M-Class The BMW X5, Lexus RX, and Volvo XC90. The design and construction of this model are similar to those of the Volkswagen Touareg and Porsche Cayenne series in the same group. The new Audi Q7 has officially been launched in China, representing the Audi brand's entry into the domestic SUV market. The top luxury SUV market is the first to be seized. With its extraordinary charm, the Audi Q7 has also attracted the attention of many consumers in China. Recently, Audi announced that, The Audi Q7, a large SUV, will launch the 2010 new model, which will be equipped with new LED lighting and human-machine interface design