Is the 2019 Camry 2.0's WCVT a downgrade? That's because you don't understand WCVT.

A few days ago, I wrote an article about CVT, titled "I want to seek justice for those CVTs that you have wronged", and netizens discussed or expressed their feelings a lot. Many people also asked me, Toyota has launched a WCVT gearbox, which is used in the latest Camry 2.0 car. What is this CVT gearbox like? Why is it called WCVT? Is it a reduction in configuration to replace the old 6AT? Given that this WCVT is indeed relatively new and quite different from ordinary CVTs, it is necessary to write another article to answer questions.

Let me first introduce this WCVT. It has only been installed on Toyota cars since last year, and the first one to be used was C-HR. In terms of time, it is Toyota's latest technology. Like the Camry's transverse 8AT, it is a product of Toyota's TNGA architecture. The official name is Direct-Shift CVT, that is, fast response CVT. Because the transmission ratio range is quite wide, Toyota calls it WCVT internally, and W means wide range. This gearbox, like most CVTs, is mainly composed of three parts: torque converter + CVT box + solenoid valve body, among which the CVT box is the most special part of WCVT.

What’s special about WCVT?

We know that manual transmissions rely on gear meshing to transmit power, and different groups of gears achieve different transmission ratios; this type of transmission has high transmission efficiency in each gear and a fast starting speed, but its disadvantage is that the gear shifting shock is large.

The CVT transmission relies on the friction of the steel belt to transmit power, and the two sets of V-shaped wheels continuously change the effective diameter to achieve different transmission ratios; this transmission is smooth and there is no gear shift gap, but it is inefficient and slow at the start, and has torque mutation protection.

The two types of gearboxes originally belong to two different ways of thinking and have nothing to do with each other, but Toyota's WCVT mixes the two gearboxes to complement each other's strengths. It adds a set of starting gears to the traditional CVT, and uses gears to transmit power when starting and at low speeds. When running, it switches to the steel belt power transmission mode to achieve overall high efficiency and smooth and fluent effects. This kind of mix and match style is currently quite common, mixing fuel engines and 48V electrical systems, AT gearboxes and electric motors, etc., can all achieve complementary advantages.

In fact, different brands usually have different ideas about the evolution of CVT. For example, Subaru or Jatco (supplying Nissan, etc.) tend to think in an engineer's mindset and like to tackle tough problems. They focus on the difficult parts of CVT. For example, if the steel belt has low power transmission efficiency, they try chains; if CVT responds slowly, they improve the friction surface material and use rare materials and advanced technology to make CVT respond faster.

When it comes to developing CVT, Toyota likes to think about problems from a market perspective. For example, consumers are afraid of CVT slipping and feel that slipping is unreliable, so Toyota provides a no-slip solution. The method is to use gears to transmit power at the start, and after running, after passing the inefficiency zone (the inefficiency zone is actually the perceived powerlessness zone and possible slipping zone), switch to steel belt power transmission. In this way, the efficiency of the starting stage becomes higher, fuel can be saved in urban areas, and the advantage of the smoothness of the CVT gearbox is retained, and consumer concerns can be technically resolved. Toyota engineers came up with WCVT based on this idea.

What’s so great about WCVT?

Of course, it is still hard to say whether it can really dispel consumer doubts. I think this may require a cognitive process. Just like many people understand the inefficient area of ​​​​CVT as a slipping area, although it feels right, from a technical point of view, it is essentially inefficient, and then produces a sense of powerlessness and lag. The addition of a starting gear to WCVT essentially solves the problem of inefficiency. This is indeed an innovation and solves a pain point in the history of CVT. Starting can be very fast, and even starting at a high speed is not a problem, because at this time it is indeed equivalent to an AT; as for starting and acceleration, once the car is running, the steel belt has a high efficiency in transmitting force and a small torque drop (similar to the reason that shifting gears after running with a manual transmission will be much smoother). At this time, WCVT switches to the steel belt to transmit power, allowing the steel belt to work in the "comfort zone", and reliability is increased.

In addition, as a new product launched by Toyota in 2018, it is necessary to introduce some improvements in other parts of WCVT. First, the locking range of the torque converter has been expanded. Toyota has actually been mentioning this technology, including the previous 6AT and the current 8AT, which can achieve locking at the starting stage, mainly for fuel saving and faster starting; second, the diameter difference between the two sets of V-shaped wheels has become smaller, and the overall efficiency of the steel belt has been improved; third, the wedge angle of the steel belt friction surface has been adjusted from the previous 11 degrees to 9 degrees, which can improve acceleration responsiveness; fourth, the use of engine oil with lower viscosity can also improve fuel saving. In short, the overall performance is definitely better than traditional CVT.

Which one is more efficient, WCVT or 6AT?

So the question now is, does WCVT have any advantages over AT? According to our usual evaluation standards, the quality of a gearbox is usually determined by the transmission ratio, efficiency, experience, and reliability. Let's look at the transmission ratio first. The WCVT transmission ratio is 7.5, and the old model uses the Aisin 6AT transmission ratio of 5.4. The gap is a bit large. The larger the transmission ratio, the lower the fuel consumption while providing sufficient torque. The reason why engines can now achieve smaller and smaller displacements is because gearboxes are becoming more and more powerful. The CVT transmission ratio used by the Accord is 6.5, the Teana CVT is 7.3, the Camry 2.5's 8AT transmission ratio is 7.8, and the Regal 9AT's transmission ratio is 7.56. If the transmission ratio of the gearbox is regarded as the CMOS of a camera, the WCVT is at least close to the full-frame level.

Let's take a look at efficiency. Compared with CVT, the published data shows that WCVT has a significant 6% increase in efficiency. Aisin 6AT is a product from ten years ago. We haven't found the exact efficiency data, but we can look at the fuel consumption data of the two cars to make an indirect judgment. The 2018 Camry 2.0 with 6AT has a comprehensive fuel consumption of 6.3L per 100 kilometers, and the 2019 Camry 2.0 with WCVT has a comprehensive fuel consumption of 5.5L, which is a 12.7% reduction in fuel consumption. Of course, this 12.7% is the joint contribution of the new 2.0L engine and WCVT gearbox. The engine efficiency improvement of 4% is already the best. With such a rough estimate, it is also true that the WCVT gearbox has a great improvement in efficiency compared to the 6AT.

In fact, we have to believe that the changes brought about by new technologies are much faster and better than we imagined. Although I am not optimistic about electric cars, the technology has indeed improved rapidly in the past two years, the battery life continues to increase, and the stability is also improving. For example, some time ago I bought a 512G USB flash drive, which is larger than my laptop hard drive, but its size is even smaller than a No. 7 battery. It is plug-and-play and very fast, and it can completely revolutionize mobile hard drives. This makes me feel that the update of concepts usually lags behind the speed of technological updates.

Is WCVT more expensive or 6AT?

We have driven both models. The new Camry with WCVT has more than 5.5% more power and torque than the old Camry with 6AT. The difference in power is not obvious, but the new Camry 2.0 is better in terms of driving smoothness. Of course, if you want to drive more dynamically, WCVT still provides manual upshifting and downshifting, and the reaction speed and decisiveness of acceleration execution are no less than the previous 6AT. In a word, we still have to believe in the changes brought by technology.

I don't know if you have read our column "Parts-to-Whole Ratio". That column mainly talks about the price of auto parts. If you haven't read it, you can look through the previous articles. Let's talk about the prices of the two gearboxes, WCVT and Aisin 6AT. The price we learned from the 4S store is that the WCVT gearbox is 4.4% more expensive than the original 6AT. In terms of cost, the 6AT is cheaper. Of course, this may be due to the fact that the 6AT has been mass-produced and the price has dropped, but it also reflects that the technical content of the WCVT is not low at all.

Finally, let's talk about reliability. If you ask me which one is more reliable, WCVT or 6AT? This question is really hard to answer. I may inertia prefer 6AT, because Aisin 6AT has been tested by time, and WCVT is still a new product. If you ask me whether I would choose Camry with WCVT or Camry with 6AT, I will definitely choose Camry with WCVT. After all, the new experience brought by new technology is much better, and there is also fuel consumption and technical superiority. As for reliability, they are both Toyota brands and WCVT is also manufactured by Aisin. These two guarantees are enough.