[YesAuto original test drive] “Icebreaker Yacht” may sound a little abrupt, and I don’t know how I came up with this metaphor; maybe it’s really a successful advertisement. Thinking of MDX, I can always think of the design ideas it promotes. , Is to build a luxury car with the idea of building a yacht; regardless of its price abroad, the price of close to one million in China is at least not affordable for me and most people. The yacht explained it, but what about icebreaker? Just 24 hours ago, Acura held the MDX ice test drive in Changchun. Its performance on ice and snow should be the definition of “ice breaking”.
If you are not very familiar with Acura MDX, you can click on the link below for a comprehensive understanding
● About test drive models and venues and others
Time, place, person, event are the four elements of an article, so I also need to explain the first three elements before the event.
The model for this test drive is Acura’s main SUV—Acura MDX. The car is equipped with a 3.7L V6 engine and a 6-speed automated manual transmission. The power performance is relatively satisfactory. The SH-AWD full-time four-wheel drive The system is also an absolute selling point. Please note that the test drive model is an exclusive sports version that has not yet been put on the market, which will be described in detail below.
Spring is about to begin. Beijing has only a brief snowfall this winter. Is the climate really abnormal? Anyway, I had to wear wool trousers when I was young, but now I don’t use it at all. Therefore, you can only go to the ski resort to find ice and snow in Beijing, while the northeast is different. Relying on the geographical advantages of high latitudes, many manufacturers' ice and snow test drives are arranged in Heilongjiang and Jilin provinces. This Acura event is in Jilin. The provincial capital-Changchun. The specific location is Jingyuetan, which has 4.3 square kilometers. The outdoor temperature in Changchun during the day is around -17°C.
Changchun first feeling
When I came to Changchun for the first time, the feeling of the old heavy industry city was very obvious. There were slightly old trams running through the city, and the windows were covered with ice flowers. The roads are full of FAW-Volkswagen cars, but there are no high-end models. I am very interested in the diesel Magotan on the road. The drivers here seem to be used to the ice and snow roads and their driving style is more unrestrained. One point in the city makes me wonder, why are there so many car rental shops on the streets of Changchun? Is the car rental market here mature?
● Introduction of Acura MDX Exclusive Sports Edition
The exclusive sports version will go on sale in late January. The difference from the models on sale is the addition of exterior kits, or just the addition of exterior kits. The first is the front face part. The front bumper has a lower surround with a silver guard, which looks more rugged. A chrome-plated decoration is added to the engine compartment cover, which is integrated with the chrome-plating of the air intake grille. The complex front face with clear lines has a strong sense of thickness.
The rear part echoes the front face, and the rear bumper also adds a surround similar to the guard plate; from the side, it is not difficult to find that the chrome-plated metal luggage rack is also the standard equipment of the exclusive sports version. It can be said that the exclusive sports version is a product that was born to meet the appearance and personality requirements of different consumers.
The 19-inch chrome-plated wheels are more eye-catching, and the multi-spoke design of varying widths increases the sense of movement while maintaining a sense of luxury, which is a bit close to the “VIP style” we often call. The model tested this time did not use studded tires, but used Yokohama winter tires. To be honest, the performance of this set of tires is indeed good.
● Explanation and preliminary test drive
The test drive site is on the frozen lake, and the abstract “SH-AWD” font is placed in pile buckets. Each letter contains the test drive project, but the main purpose of the project is to let everyone experience the four-wheel drive system. So in the following, I will select representative projects for introduction, and I won’t mention the repetitive content.
All projects are for the performance of SH-AWD, so what is SH-AWD? How is it different from other four-wheel drive?
The full name of “SH-AWD” is four-wheel drive free control system. It is not difficult to see that it contains an important point, which is “free control”, which is different from other four-wheel drive. This system can not only realize the torque distribution of the front and rear wheels, but also can perform stepless torque control on the left and right wheels on the rear axle to improve the controllability and safety. It is mainly reflected in the stability of turning. The system uses torque. The allocation processing is not conducive to the physical posture of the steering, which makes the control smoother.
So how is the free control achieved? A set of electronically controlled multi-disc clutches are installed between the rear axle wheels to control the torque of the left and right wheels, so that the posture is better controlled when turning, and the probability of over and under steering is reduced. In the extreme state, 100% of the power obtained by the rear axle can be allocated to a single wheel. In addition, the torque distribution of the MDX front and rear axles is different from that of the RL that also uses SH-AWD. MDX can output up to 90% of the torque to the front axle, while the RL is up to 70% of the torque.
If you are not so sensitive to the dynamics of the car, you can see the torque distribution of the system to each wheel through the small display on the center console. In order to show the torque change, I made a lap to the left and depressed the accelerator deeply. At this time, the system transmits most of the power of the rear axle to the right rear. The reason is that the computer thinks that I am turning to the left, so I turn the power to the right. Rear transmission, and VSA intervenes to apply braking force to the left rear wheel.
The basic experience starts below. Because I am not familiar with the car and the road, I turned on the VSA; in fact, the VSA body stabilization system and the SH-AWD cooperate with each other. When cornering at a faster speed, the VSA will intervene, and the torque will start at the same time. Active allocation, the two can pull the car back to a normal posture very well, and it is easier to drive. But since it is an ice and snow test drive, you must experience the characteristics of the ice and snow road. Because the VSA will inhibit the power output and greatly reduce the driving excitement, the VSA is decisively closed.
● Correction of oversteer and understeer
After turning off the VSA body stabilization system, the vehicle began to become unstable, and the effects of many actions on the ice surface would be magnified. When oversteer occurs, the rear of the car will slide outward in parallel. It is relatively simple to correct the oversteer. You only need to reverse the direction immediately. After the reverse direction, the car body is smoothly corrected, but it still needs to be controlled on the accelerator.
It feels helpless when facing understeer, the direction is clearly pointing to the bend but the car still slides outward. In fact, understeer can be remedied to a certain extent. The method is to first turn the steering wheel back to the out-of-control direction. At this time, the grip of the tires will instantly recover, and the vehicle will be pulled back immediately. Correction of the direction. It’s just that you need courage to do the first step. After all, you are adjusting the body in a direction that loses control.
The explanation of the operation technology sounds simple, but in the actual operation, a clear mind is required. When a situation arises, it is necessary to adjust the direction and throttle control immediately. If the reaction is not timely or the direction is changed blindly, even if it is finally found that the situation is out of control is irreversible, and the deceleration measures are actively taken, then the ice surface with extremely low adhesion will not stop.
● Several characteristic items
The first is the emergency line change project. In fact, this project is designed in many test drive meetings. Their purpose is to let the driver experience the effect of the body stabilization system. In this test drive meeting, we turned off the VSA, so the body The adjustment is entirely on your own, and you can feel the tracking agitation brought about by the large torque output of the rear wheels when exiting a corner. Of course, our speed must not be as fast on the asphalt.
Artificial snow is used to build a bridge. The key is to control the throttle when going uphill. It must be steady. Sudden acceleration or deceleration in the middle may make it impossible to go uphill; because MDX does not use nailed tires, it is inevitable to slip. I feel that the driving force of the wheels has been lost for a while, but the top of the slope can be reached with the help of electronic limited slip, but it is not so flat. The key to going downhill is slowness. Because the exclusive sports version adds an appearance kit, there is a slight loss in the approach and departure angles. Because the slope is very slippery, it is necessary to control the braking force, even if it is snow tires. There will be a small decline, but it is no problem to go downhill at a very slow speed.
Experience on roads with different adhesion. When the left and right wheels are on roads with completely different adhesion, the wheels on pure ice will surely slip. At this time, the electronic limited slip starts and torque starts to be transmitted to the wheels with adhesion, and the start is relatively smooth. , There is no obvious abnormality; strong braking ABS starts naturally, and the braking force distribution EBD reduces the possibility of deviation due to different adhesion.
Concentric circles are actually a very exciting and fascinating project. I immediately thought of Ken Block's perfect drift (click the link to view Ken Block's drift video). I imagined that I could imitate 30% to be content; although I have mastered the turn Excessive and inadequate control methods, but in the face of continuous conditions, such as: the excess has just been corrected, followed by excessive or insufficient; the performance is still in a hurry, not to mention the road conditions are more complicated, so in the end it is not drawn into a circle at all. According to the coach, it is very difficult to drift around in circles.
In the side slope project, the MDX body has good rigidity. When passing through, the front and rear wheels on the right will be suspended for a short time. At this time, the test is the torque distribution. With the help of electronic limited slip, there is no significant loss of torque. The cross shafts pass more easily. The tilted body is indeed a psychological challenge. When the wheels are suspended for a short time, no obvious idling is felt, and the whole process is smooth.
The ribs road mainly tests the performance of a car's suspension. Because the “ribs” are staggered, it also needs effective limited slip and power distribution to pass. In this project, the MDX suspension showed its model positioning. The tuning is more comfortable, and it doesn't feel so heavy. In fact, it is more suitable for comfortable driving on paved roads.
to sum up:
After reading the article, I don’t know if you have any understanding of “Icebreaker”. It is said that SH-AWD can allow you to drive calmly on icy and snowy roads, and it can improve driving safety on wet and slippery roads in cities. The torque distribution improves stability and handling in corners. Regardless of the power configuration, driving experience and comfort of this car, I can score a higher score. However, the current domestic market is under certain pressure on the price and brand. Acura will be in the future for a long time. Establishing a brand image and recognition is a very important task. Although it will not and cannot be as popular as Honda, at least it must be more integrated into the market. (Photo/Text/Photographed by Zhang Ke, Car Home)
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