Infinitely close to EV! Detailed explanation of Honda i-MMD plug-in hybrid
[car home Technology] Honda has been deeply involved in the field of automobile hybrid for a long time. Honda began to promote hybrid cars in 1999, and now it has accumulated technology for 20 years. In the past two decades, in order to meet the changes in the market and the diversified choices of customers, Honda’s hybrid system has spread to various important models, from the people-friendly Fit to the high-end NSX, and this year it has also expanded to MPV models (|), Ailishen), and the product selectivity has become more diverse. In addition, the i-MMD plug-in hybrid system based on the overall upgrade of Honda’s i-MMD hybrid system will also be officially unveiled in the China market next year. According to the introduction of engineers from Honda Institute of Technology, this plug-in hybrid system (PHEV) based on i-MMD basically realizes pure electrification in daily driving, which can be called a brand-new plug-in hybrid system infinitely close to EV.
Before the 11th National Day, I came to Guangzhou specially and had a detailed exchange with engineers from Honda Institute of Technology who came from Japan. This article will introduce this i-MMD plug-in hybrid system in detail. If you have any questions, you are welcome to discuss it in the message area.
◆ Preface: Starting from the promotion history of Honda hybrid cars.
In order to let everyone know better about Honda’s newly released i-MMD plug-in hybrid system, I think it is necessary to briefly explain Honda’s promotion in the field of hybrid vehicles, so as to have a more comprehensive understanding of new technologies in the future.
Generally speaking, IMA design is very clever, and at the same time, because the motor has low power and small volume, it can be well integrated in the engine compartment, so the biggest feature of this mechanism is simple structural design, light weight and compact layout.
The Civic Hybrid model based on the seventh generation Civic (overseas version) has also entered the domestic market, and it is also the second hybrid model launched by Honda after INSIGHT. Civic Hybrid is also equipped with IMA hybrid system with engine as the main power and motor as the auxiliary power.
In IMA system, the position of motor is very low, which is similar to the function of 48V BSG motor from the present point of view. The difference is that this system switches the working mode instead of the power distribution mode. To put it simply, Honda IMA hybrid system has five working modes, in which the engine and motor work together in the initial acceleration stage, rapid acceleration and high-speed driving stage, which can improve the dynamic performance of the vehicle. When the vehicle runs at a low speed, the engine cylinder is closed, and the vehicle can be driven by full electric power, but the speed cannot be higher than about 40 km/h. When the vehicle is completely driven by the engine in the ordinary acceleration stage, the motor is out of work and charged with the kinetic energy of the engine.
A big problem with this system is the above-mentioned engine off and full electric drive condition. When the engine is turned off here, it actually turns off the oil supply system and the intake and exhaust. At this time, the motor is connected with the crankshaft, and the motor actually drives the crankshaft to rotate and output power. At this time, more energy will be consumed, and the mileage of pure electric driving is very low.
The appearance of IMA marks that Honda has officially begun to exert its strength in the hybrid field, and it is also the starting point for Honda. In addition, many R&D concepts of this system, including integration and miniaturization, have had a far-reaching impact on the later iMMD system. Even the i-MMD plug-in system released this time can still see some R&D concepts in the IMA era.
◆ Fundamentally: Honda’s mixed "spiritual leader"
With the innovation of technology and the change of market, Honda is obviously aware of the limitations of IMA. At the same time, compared with Toyota’s THS, Honda’s IMA is really not cheap. A more efficient and more dynamic hybrid system is coming out. This is Honda i-MMD system. This system appeared around 2010, and the structure changed from single motor to double motor. The layout is still compact and combined with the engine and installed in the engine compartment. In fact, we have introduced and tested Honda’s i-MMD system in detail before. In this article, we only make a simple review, which will help you to understand the plug-in hybrid system of i-MMD more clearly (plug-in hybrid is essentially an upgrade of i-MMD system), and also better understand the working principle of i-MMD plug-in hybrid system.
I-MMD system can be divided into two parts according to the layout structure: one is located in the engine compartment, and the other is located in the rear of the car (between the trunk and the rear axle). The engine compartment is mainly the power system and transmission system of i-MMD system. The trunk is a power battery (lithium ion) device.
In the world of unplugged hybrid systems, the logic of the i-MMD system is very unique. If Toyota relies on engines and motors to mix in different proportions, then the i-MMD system is more like switching by different driving modes.
It can be seen that EV mode is driven by electric motor, and the engine of i-MMD system can not work at all in pure electric mode because of the direct clutch of engine and the addition of higher power motor, thus avoiding the extra loss of power in IMA before. However, even with the i-MMD system, the mileage in pure electric mode is very short. For example, the battery of the 2016 hybrid Accord is only 1.3kWh, and we tested pure electric driving at 30km/h (without air conditioning), which is only 1.77km. (Test article: Satisfy your curiosity. Deep technical interpretation of Hybrid Accord)
The hybrid mode is the standard series mode, which is a bit like the feeling of extended range. The engine does not participate in direct wheel drive, but drives the generator to generate current, which drives the motor to work together with the current in the battery, and finally drives the vehicle forward.
Only when cruising at high speed will the engine directly drive the wheels, at this time, the engine can keep in the optimal speed range and achieve a good fuel consumption performance.
In Honda i-MMD system, the motor plays a more important role, so the maximum power or torque of the motor is better. In daily use, it is more inclined to the direct output of the motor, and the engine is somewhat similar to the extended range.
Toyota’s THS is more inclined to engine-driven vehicles, and the motor is more auxiliary, such as assisting when accelerating, assisting when starting, etc. These assists are more to keep the engine in an economical speed range, thus improving fuel economy.