It is said that Xiaoming bought a new car and happily drove home to let his relatives and friends appreciate it. Naturally, everyone was full of praise, saying that this car was really good, and Xiaoming was really powerful. Xiaoming was very happy to hear it, and he was a little fluttery.
Suddenly, a relative pulled Xiaoming aside and whispered to Xiaoming, "Is there something wrong with your car?" I see that the engine is crooked, is it an accident car? ”
Xiaoming took a closer look, but it wasn't, the engine was crookedly placed in the engine compartment, looking very awkward. Other relatives and friends also saw this, but they did not have the good sense to say it. Xiaoming's face instantly darkened, got on the car to close the car door, drove the car back to the 4s shop, entered the store and shouted: "Hurry up and give me the car refund compensation!" What a broken car, the engine of the new car is crooked! ”
The service consultant hurried over to say hello. Listening to Xiaoming's reason for returning the car, he couldn't help but laugh dumbly, and told Xiaoming that this is normal, and many cars are like this.
Xiaoming naturally did not believe it, and the new car installed the engine crookedly, and said that it was normal and too cunning. This is the quality problem, is the car company manufacturing technology is not qualified. Hurry up and return the car, I will never buy your car again!
The service consultant saw that it didn't make sense to Xiaoming, so he asked Xiaoming if he had any friends who knew a little about cars. Bob thought of me and called me and asked me to come and help him. When I got to listen to it, I knew what was going on, quickly pulled Bob aside, and gave him an engine technology lesson.
I told Bob that it was normal for the engine to be crooked. Not only your car, but also many other cars are arranged in this way, but the degree of tilt is different. The purpose of the tilting arrangement of the engine is mainly to make the engine and the transmission system better coordinate and cooperate and improve the transmission efficiency.
According to the layout of the engine on the car, the engine has three forms: vertical longitudinal tilt, transverse lateral tilt and vertical tilt, which have different functions.
The engine is longitudinally and vertically inclined, and is commonly used in front-mounted and rear-wheel-driven models, such as medium- and large-sized cars and trucks. In such a model, the engine is mounted in the front, the drive axle is in the rear, and there is a long drive shaft between the two to transmit power. Because the front part is relatively high, the rear drive axle is relatively low, in order to avoid the transmission shaft bending angle is too large, let the engine have a longitudinal inclination angle, as far as possible with the transmission shaft, the drive axle to maintain a straight line, to improve the transmission efficiency. If there is no inclination angle, the bending angle of the transmission shaft is relatively large, and in the process of rotation, the cross shaft is not equal speed transmission phenomenon, and the power transmission is not only not smooth, but also the loss is relatively large. Therefore, setting this inclination angle can effectively improve the transmission efficiency. The longitudinal inclination of the general engine is between 3 and 5 degrees, and some models can reach 6 to 7 degrees.
The engine is horizontally mounted and laterally inclined, which is commonly used in front-mounted and front-wheel-drive models, such as ordinary family cars. In such a model, the engine is mounted in the front, integrated with the gearbox and drive axle, and directly drives the front wheels through the half shafts on both sides. In this arrangement, the half shafts on both sides are of unequal length and are not equal to the angle of the gearbox. This creates a special phenomenon – torque steering. When the car starts or accelerates sharply, due to the unequal force of the wheels on both sides, it will automatically deflect to one side, which has a certain danger. The purpose of the tilting arrangement of the engine is to make the angle between the left and right half shafts and the gearbox equal, reducing the tendency of torque steering. This arrangement is more common on Volkswagen cars, and the lateral inclination of the engine is generally between 3 and 5 degrees.
The engine is tilted in a vertical direction, and the main purpose is to reduce the height of the engine and lower the center of gravity of the car. In order to pursue low speed and high torque, some engines often use a relatively large piston stroke; at the same time, in order to make the engine cylinder block have a large stiffness, the crankcase is generally designed as a gantry type. The engine designed in this way is relatively large in the vertical direction, and if it is directly mounted on an ordinary family car, it will cause the front cover of the car to be too high, the center of gravity of the car to be too high, and the handling to decrease. By tilting the engine and letting the engine lie half in the engine compartment, you can reduce the height of the engine, thereby reducing the car's center of gravity and improving the car's handling performance. This arrangement was more common in the early Volkswagens, such as Poussin, the old Jetta, the old Audi and so on. In addition, the engine tilts vertically, and the position of the engine in the engine compartment can also be adjusted, such as the Volkswagen MQB platform to unify the inclination angle of the engine arrangement to 12° inclined to the crew compartment, shortening the distance from the front axle to the front of the body and expanding the crew compartment volume.
The engine inclination is mainly formed and maintained by the foot pads. The general engine uses three or four points of support, adjust the height and position of the foot pad, you can form a different engine inclination angle; when the car is used for a long time, the foot pad deformation, aging and other phenomena, the engine inclination will also change, which will have an impact on the performance of the car. Therefore, the engine foot pad damage should be replaced in time to avoid motion interference in the transmission system.