Is Infiniti’s Atkinson cycle provided by Toyota?
In recent years, in order to better highlight the unique black technology of the core components of their engines, car companies often use These words are used to set off, but if you pay a little attention, you will find that Atkinson mainly appears on the products of four car companies-Infiniti, Honda, Volkswagen, and Toyota. Some promote themselves as pure Atkinson, and some say that they are pure Atkinson. It has a longer history...
Many consumers are already confused. You usually can't compete with each other, so why are they all the same now?
To tell the story of the Atkinson cycle, we have to mention the Otto cycle. In 1876, the German engineer Otto invented the engine. The Otto cycle has a history of 144 years. It integrates the four strokes of suction, compression, collision work and exhaust.
In fact, the operating principle is very simple. The downward movement of the piston causes fuel and air to mix into the cylinder, and at the same time the intake valve is closed. The piston then moves upward to compress the gas mixed with air and fuel. It ignites at the top, and the explosion generates thrust to push the piston downward, and then the burned gas mixture is discharged.
The four steps are clear, so the Otto cycle is also named a four-stroke cycle. It is also an ideal thermodynamic cycle for constant volume heating. Compression ratio = expansion ratio, which means you want more power. , a larger compression ratio is needed, but if the compression ratio is too high, it will cause knocking. These are problems and limits that need to be overcome.
Illustration: Atkinson’s patent drawing in 1882
Then today’s protagonist Atkinson appeared. In 1882, the British engineer James Atkinson passed The connecting rod overcomes this problem and increases the total stroke of the piston when it is expanding to do work. The air intake efficiency is greatly improved, more kinetic energy is obtained, and the power stroke gt is achieved; the compression stroke achieves the expansion ratio gt; the compression ratio, fuel efficiency His performance was better than Otto's.
However, the shortcomings are also a bit obvious. The connecting rod structure is too complex, takes up too much space, and the torque is slightly insufficient at low speeds, so it has not been widely promoted and applied.
Illustration: Atkinson motion diagram in 1882
Although this design was not promoted and applied, the idea was recognized by everyone. By 1947, Miller, an engineer from the United States , by making trouble on the valve, the same effect as the Atkinson cycle is achieved.
On the basis of the original Alto cycle structure, he proposed the idea of ??early closing of the intake air through different valve timing. The intake valve is closed before the compression starts, and then when the piston reaches the bottom dead center When the intake valve is closed late, the effective compression ratio is achieved through variable valve closing time; the expansion ratio is reduced, the pumping loss is reduced, the knocking phenomenon is suppressed, and the thermal efficiency is improved.
Are you a little confused after saying so much? Don’t worry, it’s coming to an end soon. In 1993, Mazda took the lead in adopting this technology, optimized and improved it, and then applied for relevant patents. ——The "Miller Cycle" has become exclusive to Mazda.
Later, Toyota was forced to name the "Atkinson cycle" in order to avoid patent issues. It is mainly used in hybrid vehicles. With the assistance of the motor, it shares the burden of the engine during high loads, and the problem of insufficient power during starting and acceleration has been improved and compensated.
The current "Atkinson cycle" of Honda and Volkswagen also has similar concepts. They both make a fuss about the intake valve and control delayed closing or early closing to achieve the goal, but Infiniti did not lie. , the arrival of VC-Turbo also really reproduces the earliest Atkinson cycle, it returns to the earliest connecting rod design concept.
The advancement of technology has made the difficulties at that time worth mentioning. Through the electronic control mechanism, the engine can be switched between Otto and Atkinson at any time, achieving a variable ratio of 14:1/8:1. The compression ratio can not only solve the problem of insufficient low-end torque, but also bring better fuel efficiency.
So, the Atkinson cycle equipped on Toyota's hybrid models is indeed great, but the so-called Infiniti's Atkinson is given by Toyota is completely wrong. Toyota's Atkinson The Kinson can only be said to be the Miller cycle with a different name, while Infiniti's Atkinson is pure, although the purpose of the two cycles is the same.
But the methods are completely different. If you encounter such a sale next time, you can tell him: You are wrong, yours is the same model of Mazda's Miller cycle, and Infiniti is a real Atkinson.