However, the debut of the new car is also accompanied by many controversies. On the one hand, the power configuration of the whole 1.5T three-cylinder system will inevitably make this pillar of daily sales fall into the dead hole of three cylinders.
Is CVT gearbox really the death knell of Nissan?
On the other hand, the matching CVT gearbox always seems to be negative, "it will break after the warranty period", which seems to be everyone's understanding of this gearbox.
0 1
First, I found a problem. Why does Nissan love CVT gearbox?
Except for a few large-displacement models, the main gearboxes of Nissan products are basically CVT gearboxes, which makes CVT gearboxes an important label of Nissan.
It is not that Nissan CVT gearbox is the best choice, but for Nissan, CVT gearbox is indeed the most suitable choice under its industrial structure.
Nissan's CVT gearbox is a product of JATCO, a world-famous CVT gearbox company, accounting for nearly 40% of the global CVT gearbox suppliers. In the gearbox industry system, JATCO is also a leading enterprise. Nissan owns 75% of JATCO.
In other words, the world's largest CVT gearbox manufacturer can basically be regarded as a subsidiary of Nissan. Its relationship with Nissan is basically equivalent to Aisin and Toyota.
In this way, the cost and profit of every gearbox JATCO sells to Nissan are basically in Nissan's pocket. So even if the price is not cheap, JATCO's profit is still in Nissan's hands.
This is also the reason why the Japanese auto industry is keen to build a large supplier industrial chain system. Since Nissan is the world's largest CVT gearbox manufacturer, Nissan has no reason not to use JATCO.
02
Why is Nissan's CVT gearbox always easy to break down?
Not long ago, I hit a Scorpio in a special car. When the car started at the big throttle, it was obvious that the car was shaking and the power connection was not smooth. I didn't know there was something wrong with the gearbox until I chatted with the driver. This is the second time something has gone wrong. The first time the solenoid valve was broken, this time the steel belt was broken.
We have talked about the principle of CVT gearbox many times. Simply put, it is two tapered pulleys driven by a steel belt in the middle. When the speed ratio needs to be changed, the two conical discs of the pulley move in opposite or opposite directions, so that the steel strip is squeezed by the conical discs and the diameter around the pulley is changed, thus realizing the change of the speed ratio.
This logic is basically similar to bicycle transmission.
Therefore, it can be seen from here that the contact surface between the steel belt of CVT gearbox and the pulley cone disk is very small, only a small part of the side of the steel belt, and this small area bears all the pressure of the pulley cone disk to squeeze the steel belt.
For the whole steel belt, it has to bear the tension brought by the power transmitted by the steel belt and the pressure brought by the cone disk, which are perpendicular to each other.
So at this point, there are two places where CVT gearboxes are prone to problems.
03
First of all, the tension acting on the steel belt when CVT gearbox transmits power causes the gearbox to wear.
Anyone who has ridden a bicycle knows that the chain of a bicycle is easy to loosen after being used for a long time, and so is the CVT gearbox.
The steel strip formed by series extrusion of small steel rings will inevitably have some problems of small steel rings after long-term high torque tension. Once these problems are gradually accumulated, with the passage of time, the steel belt is easy to loosen, resulting in unsmooth power transmission and slippage of the steel belt when transmitting large torque.
Secondly, the electro-hydraulic servo mechanism drives the pulley cone to move, which is the power part to provide pressure for the steel strip. This part mainly plays two roles, one is to push the pulley cone plate to move, and the other is to keep the pressure after the pulley cone plate moves, so that the CVT gearbox can work in the set transmission ratio.
The concept of simulating seven-speed and eight-speed that Nissan often puts forward is actually that the conical disk keeps several fixed positions for a long time.
Then the problem is coming. After long-term operation, the valve body of the electronic valve that keeps the pressure of the pressure plate will be worn to some extent. Once worn, the pressure that the solenoid valve body can provide to the pressure plate will be insufficient, which will lead to the cone disk not being able to hold down the steel belt and the gearbox slipping.
In case of slippage caused by chain elongation or insufficient pressure on the pressure plate, the vehicle will inevitably be accompanied by howling or abnormal sound.
Judging from the problems of Nissan CVT gearbox we have collected so far, it is not accidental that the solenoid valve is damaged and the steel belt is worn. Most of these phenomena occur within a period of time after the vehicle over-insurance begins to break out.
In addition, the abnormal sound caused by insufficient durability of tapered disk bearings due to early cost reduction is also part of Nissan CVT gearbox problem list.
04
Low daily production cost is probably the core issue.
From the principle of fault outbreak, the faults of Nissan CVT gearbox are the characteristics of CVT gearbox. Just like the clutch plate of a manual transmission vehicle will break, the electromagnetic valve of an automatic transmission has failed for a long time, which belongs to normal use loss and damage.
However, if Nissan's CVT gearbox has such a high failure frequency, people have to wonder whether the low cost has lowered the material standard, leading to premature and overworked gearbox.
Low cost is precisely the key reason why Nissan walked out of the bankruptcy crisis at the beginning of this century.
At that time, carlos ghosn made a low-cost prescription for the daily production of technology and set off a profit-oriented low-cost enterprise operation strategy. The end result is that Nissan has come out of the crisis, but the technical Nissan has become the past.
In addition, we have every reason to believe that Nissan's CVT gearbox may really cut corners due to the frequent fraud incidents exposed by the Japanese steel industry in recent years.
In addition to the fault, Nissan's CVT gearbox also has a very unacceptable setting, supercooling protection.
This point, the northern car owners should have a deep understanding. In order to ensure the durability of the gearbox, Nissan CVT gearbox is equipped with cold-proof logic. Before the oil temperature of the gearbox reaches the working temperature, the vehicle can only maintain a very low speed and drive slowly. At this time, CVT gearbox will not shift gears. And this process often lasts for several kilometers.
So, where is Nissan's technological road?