Producer: Observer Network Car Channel [Official Number: Engine Sight]
Author/Editor: Lou Bing
With the deepening of the electrification process, the driving method of the car has changed greatly than before, on the one hand, it is easier to achieve, on the other hand, the performance is easier to improve. This is a significant change that has not attracted widespread attention from the market and consumers for the time being.
Toyota's new E-Four four-wheel drive system is based on Toyota's proud TNGA-K architecture, and the advantage of the Toyota E-Four electric four-wheel drive driven by the electric system is that the Toyota E-Four is driven by a conventional fuel engine in the form of driving the front wheels, and the electric motor drives the rear wheels.
Toyota's E-Four electric four-wheel drive system can reach up to 20% of the front and 80% of the torque distribution ratio in certain situations, which increases the rear drive characteristics of the vehicle, so that the vehicle's handling performance is improved during driving. At the same time, the electric drive rear wheel is also relatively stronger than the traditional four-wheel drive in noise suppression.
The industry knows that Toyota is the originator of hybrid technology. With its strong fuel economy, the hybrid system is well known on the market. Especially in recent years, hybrid models have become more and more accepted in the market. So, when this hybrid system and the E-Four electric four-wheel drive system are combined on Velanda's body, what kind of chemical reaction will occur?
01
THS+P4 motor
Toyota's E-Four system, which is now installed on many hybrid models, is a four-wheel drive with a very simple and refreshing structure, light weight and a high degree of miniaturization. Compared with the ordinary THS hybrid model, or dual engine model, the E-Four is directly on the rear axle to add a small motor, currently only provides 54Ps unified maximum horsepower specifications.
People who have a certain understanding of the mainstream discrete PHEV models in the European market and the Chinese market know that this is actually a motor located in the P4 position and does not participate in any mechanical transmission with the internal combustion engine power unit. Whether it is a BYD Tang (previous DM-i model) or a Peugeot 4008 PHEV or a Ferrari SF90, there are such units.
The remaining two motors are deeply coupled to the combustion engine to form a THS hybrid system. At present, the whole network is very accustomed to understanding Toyota's dual engine model as equipped with an E-CVT gearbox, but I personally think that the so-called E-CVT is actually the core of the entire THS system (power shunt device).
In the latest generation of THS systems, the flow of energy between one engine and two heteroaxial motors is linked by planetary gears. The large motor is located in the ring gear position responsible for the final power output, which is connected to the front wheel by means of a gear set. The engine is in a planetary position to provide additional power or drive a small motor to charge. The small motor is coordinated in the position of the sun wheel to complete the balance between the "levers".
This sounds like an extremely brain-burning power system, but as long as the constant gear ratio relationship between the three of them is clear, and the engine can only rotate in the positive direction, it can be reduced to a schematic diagram of the lever. It looks something like this:
The engine is shown driving the wheels while charging the battery with additional power.
So why does the engine have "extra power" in addition to driving the wheels? Why don't you need so much power but still produce so much torque?
This is actually the key core of the fuel economy of the THS system, which liberates the speed and torque of the engine so that it always operates in the high thermal efficiency range. Simply put, the high thermal efficiency range of the engine is generally located in the high load and low speed area. In the past, pure gasoline car engines could not independently choose the working conditions, and the speed was always associated with the speed, and the torque was always associated with the load.
But with the two motors of the THS and the planetary gear mechanism that enables continuous variable speed and torque (which is why Toyota calls it E-CVT), the motor can adjust the speed of the engine very freely. For example, in the above example, the system judges that the energy of the battery is not enough, then start the engine and keep it in the maximum thermal efficiency working range, and at this time the output of the engine is much greater than the power demand, then the remaining energy will be charged into the battery and used later.
As for the E-Four-wheel drive, when the battery is powered, it can not only generate power from the front axle, but also from the rear axle. It's that simple.
02
More stable
Regarding the actual driving experience, in the Veranda high-performance four-wheel drive version, the most important role of the E-Four is to provide a more stable and powerful acceleration experience at low speeds and improve the stability under slippery and snowy roads, which is also the official explanation given by Toyota.
Speaking of acceleration first, it is obvious that adding two working brothers to the rear axle can maximize the acceleration capacity. After all, under the working condition of this load moving backwards, the rear wheel can provide 1 point of driving force, and the speed effect of 1.1 points can be obtained.
Measured down, the Veranda high-performance four-wheel drive version can play a very stable 5-second 0-100km/h acceleration performance, the entire acceleration process in one go, the tires do not appear to be excessively skidded, the power system does not have a sense of discontinuous force incoherence, for a home SUV can be regarded as a very strong level.
Of course, the so-called 100 km acceleration performance within 6s is nothing more than "talking about capital", and more importantly, it is infinitely close to the 0 delay acceleration response brought by pure electric drive. This feature will make the Veranda high-performance all-wheel drive version extremely pleasant and comfortable to commute in the city, so that if you want to overtake, you can speed up, and there is no longer a gap between the vehicle and the driver.
In addition, the additional drive capacity of the rear axle makes driving on slippery and snowy roads more stable. Assuming driving on an ice and snow road in winter, the grip limit of a tire is only 3N, and it is naturally easy to slip if you want to output 10N force through only two tires on the front axle, and if the force of this 10N is assigned to four tires, then each can play its driving force very stably, and there is a better winter wet and slippery ice and snow driving performance.
According to Toyota, the power distribution of the front and rear axles in the four-wheel drive mode can reach 20:80, and it seems that the small partners in the northern region still have the opportunity to experience a four-wheel drive drift in the snow.
03
Take a look:
With the reinforcement of the rear axle motor of the E-Four wheel drive system, the Velanda PHEV has a more complete driving performance. Of course, this still does not affect the strong fuel economy competitiveness and leisurely electric drive driving experience brought by its THS hybrid system, which is a very good answer sheet to complete the additional additional questions. 【END】