Tell you about the new suspension and suspension adjustment

From the suspension adjustment team of vehicle engineering, this article will introduce NIO to you. OS? 2.6.1 version of the suspension features, but also to solve some doubts about suspension adjustment. ? The article is very long, and the full text is more than 5, words. If you can't finish reading it at one time, remember to click Collection, and keep it for later. The contents are as follows:? First, NIO? OS? Version 2.6.1 suspension characteristics? Second, what kind of suspension adjustment is a good adjustment? Third, the evaluation of suspension comfort? Fourth, the evaluation of suspension handling? V. Suspension adjustment, what are the adjustments? 6. What is the process of suspension adjustment at work? Vii. weilai's air spring and CDC (continuous damping control) shock absorber

I. NIO? OS? Version 2.6.1 suspension characteristics? Equipped with CDC electronically controlled damping shock absorbers, Weilai ES8 and ES6 (whether equipped with air springs or not) have three suspension modes for users to choose from, and the adjustment of the three modes also distinguishes them according to three different orientations and driving styles. ? Soft (default binding vehicle comfort mode): Focus on the riding comfort of potholes, minimize the transmission of impact force, and the body posture is very soothing and relaxed, suitable for driving on damaged roads and dirt roads during construction. ? Moderate (default binding energy-saving mode): Compared with comfort mode, it strengthens the control and suppression of undulation, reduces the slow shaking of the car body while ensuring the driving quality under general paved roads, and is suitable for normal roads and high-speed long-distance driving. ? Harder (default binding motion mode): the suspension is lowered, the damping is enhanced, the steering response is increased while the roll control is improved, and the vehicle is more active in changing lanes and entering corners, which is suitable for mountain roads and fierce driving. ? The sport mode is intended to create a sense of fighting close to the ground at all times and ensure that the tires contact the ground at all times. Although the old sport mode feels hard subjectively, it bounces too much, which will lead to acceleration slip regulation's frequent intervention due to excessive changes in traction during intense driving.

choosing the suspension mode that suits you according to your actual needs, or matching your ideal driving mode in the customized mode, will greatly improve your driving experience. ? Next, I'll tell you something about suspension adjustment. The article is very long, all dry goods. If you can't finish reading it once, remember to click on the collection and keep it for later. ? Second, what kind of suspension adjustment is a good adjustment? ? Suspension adjustment is a term that puzzles most consumers. If you give an example close to life, adjustment is like cooking. Even if you use the same ingredients, the preparation of materials, the control of heat and the proportion of seasonings are the key to determining whether this dish is delicious or not. Even if these factors are not well controlled, they can still be eaten, but they are not appetizing. This is the case with suspension adjustment. ? The quality of adjustment needs to be measured from two major aspects: comfort and handling. An ideal suspension can maintain a complete level on any rugged surface, and at the same time, it can let the driver clearly know the driving trajectory of the vehicle after driving in one direction when changing lanes. In short, it is not only like riding on the ground, but also where to hit. ? However, due to the current technical level and physical laws, no automobile suspension can be truly perfect. Manufacturers need to weigh comfort and handling according to the positioning of the vehicle type, so as to ensure that their products are recognized and loved by the target group in the market. ? For example, the million-class BMW M5, on the comfort of less than 4, 53Li；; For example, the BMW 74Li is not as maneuverable as the M2, which is only half the price. This is the result of the manufacturer's choice according to the user's positioning of the product. It is not that the more expensive the car is, the more advanced the suspension technology is, and it can lead the cheaper car in all aspects.

third, the evaluation of suspension comfort? 1, for the absorption of the impact of potholes? A car with poor absorption capacity will make the driver feel that every time he passes a manhole cover and potholes, he will feel that the seat will be kicked or pulled violently. A car with good absorption capacity will make the vibration felt by the driver's body lighter than that seen by his eyes, and at the same time, it will turn the strong pulling in front of him into a slight shaking from side to side. Poor handling will make people feel "hard". ? 2. For pavement graininess and joint filtration? Filtering is aimed at small inputs of finely divided roads, such as rough asphalt roads or joints of pavement plates. When a filtered car passes by, it will feel oily on its ass, like sitting on a slide, while a poorly filtered car is like a piece of sandpaper on its ass, full of graininess. If it is not handled well, it will make people feel "rough". ? 3. How to control the movement of the car body under the undulating road surface? The fluctuation control is roughly divided into two aspects, the magnitude of the amplitude and the balance before and after. If the fluctuation is too large, sitting in the car will move up and down excessively, and in extreme cases, the vehicle will be out of control. At the same time, the imbalance between the front and back of the ups and downs is more uncomfortable than the excessive ups and downs. The whole car is ups and downs, and it is easy to make the occupants feel uncomfortable or carsick. If it is not handled well, it will make people feel "shaky". ? 4. How can the suspension control aftershocks? Cars with many aftershocks will feel "scattered" when passing through broken roads or potholes, which is caused by the rapid jumping of the wheels because the motion energy of the wheels can not be fully absorbed. The suspension with poor aftershock control will greatly reduce the driving quality because of the cheap feeling of jitter. If it is not handled well, it will make people feel "scattered".

fourth, the evaluation of suspension handling? 1. The responsiveness and linearity to the driver's steering input? Some cars can change lanes sharply with a slight change of direction; And some cars have to fight in the direction for a while before they respond reluctantly, which is the speed of steering response; Some cars just hit the direction and didn't respond, and then they suddenly responded, which is that the linearity of the response is not good enough. ? The magnitude and linearity of steering response plays an extremely important role in avoiding danger and enhancing driving confidence in an emergency. When the driver finds the danger ahead and hits the direction in time, the vehicle can't respond in time and an accident occurs, which is extremely desperate.

2. Is the trajectory stability when the tire grip reaches the limit? To put it another way, it is that there is insufficient steering and excessive steering at the limit, and the grip of the tire is limited. It is not that the car will turn any corner if it hits fast enough and hard enough, but if the car continues to maintain its original driving trajectory when it reaches the grip limit, it can greatly increase safety.

when the vehicle reaches the grip limit and the driver stabilizes the direction, the line will get wider and wider, as if the front of the vehicle is pulling the whole vehicle and throwing it out;

when the vehicle reaches the grip limit and the driver stabilizes the direction, the line becomes narrower and narrower, just like the rear of the vehicle pushes the whole vehicle into the corner. Excessive steering is very taboo for ordinary vehicles, because excessive steering will lead to sideslip, which will make the vehicle directly hit the obstacle with the weak side. ? 3. Can the car body be tightly attached to the ground to reduce instability during intense driving? The ups and downs of the car body will lead to changes in the load of the wheels, and the grip of the wheels is directly related to the load of the wheels. If the load keeps changing, the grip will keep changing, so the driver needs to constantly correct the direction to keep the track of the vehicle. A good suspension should be able to keep the tires in contact with the ground to the greatest extent under the limited suspension stroke.

v. suspension adjustment. what are the adjustments? ? Suspension adjustment tries to find a suitable balance point by constantly matching hardware. Hardware includes spring, shock absorber (shock absorber), stabilizer bar (anti-roll bar), buffer block, suspension bushing and other seemingly ordinary parts.

1. spring? The softer the spring is, the smaller the impact force will be, but at the same time, it will make the handling of the vehicle lazy and slow, and the same impact force will consume more suspension stroke to absorb the impact energy.

2. Shock absorber (shock absorber)? The principle of the shock absorber is to use the oil in the shock absorber cylinder to absorb the elastic force released by the spring through the damping force generated by the piston and the valve plate. If the damping is too weak, the vehicle will swing up and down or even the tire will leave the ground, which will affect the handling stability. If the damping is too strong, the vehicle will bring stronger impact force when passing through the potholes, which will affect the comfort. ? The adjustment of damping is different from the choice of spring, which is quite complicated, because it depends on different wheel speed and needs to match the appropriate damping value. ? The ideal damping adjustment needs to be carried out when passing through a pit (high wheel speed? More than 1m/s) is round enough, and when it goes through ups and downs (middle and low speed wheel movement speed? .1m/s), which is achieved by changing the matching stack of piston and valve plate.

3. stabilizer bar (anti-roll bar)? The function of the stabilizer bar is mainly to control the magnitude of the limit roll and the balance on the limit. The stabilizer bar has appropriate rigidity, so that the car body can remain horizontal even if it is continuously and quickly wound around the pile, and at the same time, the grip of the four tires can be better utilized. ? However, an excellent stabilizer bar is just like connecting the wheels on the left and right sides in series through an iron bar. When passing through a potholed road, it is easy to cause the pulling feeling of the car body shaking left and right, and the driver's body will be shaken left and right quickly.

4. Buffer block? The function of the buffer block is to play an additional supporting role when the suspension is compressed to the characteristic stroke, and to provide buffer when the suspension is compressed to the limit, while protecting the suspension components.

5. Bushing? Suspension hardware, such as suspension swing arm and subframe, are all linked by rubber bushings. By changing the hardness and design of these bushings, the comfort and handling of wheels can also be directly affected.

VI. What is the process of suspension adjustment at work? ? At the initial stage of project development, we will carry out theoretical analysis with colleagues of the suspension design and simulation team. Because computer simulation can never fully simulate the actual dynamic performance of the vehicle, for example, according to the computer simulation results, a spring of 1kg/mm should be used, but after it is applied to a real vehicle, it may be found that a spring of 9kg/mm feels better.

the foundation of vehicle suspension adjustment is not a blank sheet of paper, but the approximate range of hardware needed for adjustment needs to be determined by the results of computer suspension simulation. The suspension hardware within this range is called the adjustment library. At the same time, with the advanced driving simulator of Weilai, we can start a round of adjustment before the prototype vehicle has landed, and determine the rationality of the adjustment library to prepare for the adjustment of the real vehicle.

after getting the prototype, we will receive all kinds of springs with different hardness, stabilizer bars with different thickness and bushings with different hardness from suppliers. We will first load the hardware according to the benchmark results of suspension simulation, and then fine-tune the hardware according to experience, so as to obtain maneuverability and comfort beyond the pure computer design state. ? But at the same time, suspension adjustment is a process that affects the whole body. For example, when you replace a harder spring, you may have to replace a thinner stabilizer bar at the same time, so the whole process is not as simple as point-to-point one by one.

A complete suspension adjustment process includes: 1. Tire selection; 2. Rigidity matching; 3. Adjustment of shock absorber; 4. Steering adjustment. Because there are several stages in the test car, and the changes made by other departments and functional blocks will also affect the suspension performance, these steps should be repeated 3-4 times with the development. ? A set of procedures, that is, a round of suspension adjustment usually lasts 3-4 months, so for our team, the car is our desk. All kinds of public roads and test sites are our office locations. ? In addition to the above-mentioned adjustment tasks during the vehicle development period, we also need to analyze the market feedback, evaluate and verify the design changes and support the media test drive in the gap of adjustment.

1. tire selection? As the only medium between the car and the ground, the tire is very important for the handling and comfort of the whole car. At present, mainstream car manufacturers will require tire suppliers to develop tires for their own models separately. ? At the beginning of type selection, the supplier will provide several tires with identical external specifications but slightly different internal structure or rubber compound formula, and select the best one. In the months before the next round of adjustment, the tire supplier will improve the tires, and at the beginning of the next round, several tires with the same appearance will be brought for selection. As the suspension of each round of adjustment is adjusted more carefully, the performance of the tires will also be selected with the state close to mass production.

2. Stiffness matching? Stiffness matching is the selection of elastic components of suspension, such as spring, stabilizer bar, bushing, etc. The related knowledge points and trade-offs have been introduced in the previous space. The ultimate goal is to lay the foundation for the adjustment of the shock absorber. This part of the work usually lasts about one month, and it also needs 2-3 rounds of iteration.

3. how to adjust the shock absorber? The adjustment of shock absorber is to control the flow of oil to produce resistance by changing the valve and piston, thus changing the dynamic performance of the vehicle. Every time you change, you need to disassemble the shock absorber and open the shock absorber to assemble the valve plate. Plus the evaluation time, you can only try five sets of shock absorbers at most a day, and the process of adjusting the shock absorber usually lasts about one month. ? The adjustment of the electronic control damping of CDC started after the hardware adjustment of the shock absorber. The adjustment process of CDC is much easier, and it is not necessary to disassemble the whole process, only the working logic of the electromagnetic valve in the shock absorber needs to be modified by the computer. A good hardware adjustment of the shock absorber is the basis of CDC adjustment. ? 4. Steering adjustment? Nowadays, most automobile manufacturers use electronic power steering, and the motor drives the rack and pinion to generate power. However, the way this motor generates power can be carefully adjusted, and it is very important for the steering feel and driving confidence. For the details of steering adjustment, a separate article will be written in the future.

VII. Weilai air spring and CDC (continuous damping control) shock absorber? With the help of more and more developed chassis technology, the balance between comfort and handling is no longer a fish and bear's paw. As an independent high-end luxury brand, Weilai is also at the forefront of its own brand in this respect.

1. air spring? The air suspension, which is commonly referred to as air spring suspension, is strictly called air spring suspension. It converts the mechanical force conduction of the steel spiral spring used to bear the car body into air pressure to support the car body. The advantage is that it can filter the small input of the road surface very well and enhance the driving texture.

At the same time, the air spring will automatically level the car body according to the change of load to ensure the posture of the car body when it moves, and automatically adjust the air pressure according to the load to adjust the natural frequency of each wheel, which is why someone will hear the air pump sound of air suspension inflation and deflation after getting on and off the car. ? Without the air spring, the back row is full of people, so because of the change of mass, the posture of the car body and the natural frequency of the suspension will be affected, and the suspension may bottom out earlier because of excessive compression, and at the same time, because of the reduction of the natural frequency, it will bring more shaking.

the third advantage of the air spring is that it can manually or automatically change the height of the car body as required. For example, the movement mode will automatically reduce the lifting control of the car body, and the easy loading mode will be minimized to facilitate the loading and unloading of goods. When driving at high speed, it will automatically reduce the height of the car body, reduce wind resistance and increase the endurance.

2. CDC (continuous damping control) shock absorber? CDC is a registered trademark of ZF. Does it mean Continues? Damping? Control? Continuous damping control, as the name implies, means that the damping of the four shock absorbers will change in real time while driving. By installing an electrically controlled solenoid valve in the traditional shock absorber, the damping of the four shock absorbers will change in real time.