In the last issue, we explained the "p2 motor" in detail, today we will talk about the "p3 motor" and casually explain the origin of the "p2.5 motor".
"p3 motor": a good employee who is deeply rooted in the "grassroots"
The "p3 motor" is usually placed at the end of the "transmission" and coupled with the "output shaft" of the "transmission", usually using a "gear" or "chain" transmission. The working mode is shown in the figure above: "engine" → "clutch" → "transmission" → "p3 motor" → "reducer" → "wheel". Therefore, the "p3 motor" has the following characteristics:
Schematic diagram of the p3 motor
1. Pure electric drive is more direct: "p3 motor" is usually connected to the "axle", so under the working conditions of pure electric drive, it can more efficiently output power to the "wheel", which can be described as "a good employee who is deeply rooted in the "grassroots";
2. Stronger kinetic energy recovery ability: Similar to the previous principle, when the vehicle is taxiing or braking, the friction generated by the "wheel" can be more directly fed back to the "p3 motor", which just confirms the old saying that "the near water building platform gets the moon first";
Top view of the structure of the p0p3 motor architecture (BYD DM-p dual-engine two-wheel drive mode)
3. Unable to start the "engine": Since the "p3 motor" is separated from the "engine" by the "clutch" and the "transmission", it is impossible to start the "engine", so we can rarely see the hybrid architecture equipped with only the "p3 motor", and generally equipped with a powerful "generator" ("p0 motor" or "p1 motor") to meet the needs of the "engine" automatic start and stop;
4. The relationship with the "transmission" is delicate: since the "p3 motor" is behind the "transmission", in the pure electric drive condition, it is necessary to drag the "transmission" on the front end, and to some extent, the "transmission" at this time becomes a burden to the "p3 motor". In addition, the "p3 motor" will also take up extra space, which makes the "front-drive" traditional car's already stretched "engine compartment" space more anxious, so engineers began to reconsider whether to move the traditional "transmission"!
"Hybrid Transmission": Simple but not simple
The mechanical transmission consisting of a gear set and a clutch set is slightly bulky
In the popular science article of "motor" that I wrote earlier, it was mentioned that it has a characteristic: "motor" can be used for speed regulation - mainly relying on the "electronic control" mechanism to "convert" or adjust the size of the voltage to control the speed of the "motor". Therefore, pure electric cars generally do not use the bulky "transmission" on traditional fuel vehicles.
Hybrid transmission with multi-axis dual motors (hand-painted)
When the engineers removed most of the "shift gears" from the traditional "transmission", leaving only a few "shift gears" (usually used to increase torque at start-up, also known as "reduction gears" – reducing speed and increasing torque) and "transmission gears" (usually used to transmit power), they designed a "hybrid transmission" consisting mainly of multiple "drive shafts", "clutches", "generators" and "drive motors" (pictured above).
Hybrid transmission with multi-axis dual motors
If you look closely at this structure, you will find that the "generator" is located in front of the "clutch" behind the "engine" and is rigidly connected to the "engine" by the "transmission gear", which meets the definition of "p1 motor"; the "drive motor" is located behind the "clutch" and is connected to the "axle", which is more in line with the definition of "p3 motor". Therefore, we summarize this "hybrid transmission" into a "p1p3 motor architecture".
How a hybrid transmission with a multi-axis dual motor works (GIF)
Let's see how this "p1p3 motor architecture" works? Please pay attention to the color correspondence in the following picture: blue indicates the flow direction of pure electric drive power; red indicates the flow direction of the "engine" power supply; purple indicates the flow direction of the power hybrid output; green indicates the flow direction of kinetic energy recovery; orange indicates the flow direction of charging; and gray indicates the state of non-participation in output work.
Pure electric mode: The working principle of this mode is very simple, "battery" to "p3 motor" power supply, "p3 motor" drives the vehicle alone, "engine", "p1 motor" does not work, "clutch" is in an open state;
"Engine" direct drive mode: When the "engine" is in efficient operation, the "clutch" coupling allows the "engine" to drive the car alone. This is rare, because the lack of traditional "transmissions", "engines" are difficult to achieve the efficient range;
Hybrid series mode (extended range mode): "Engine" - "p1 motor" - "p3 motor" is connected in series, so the "engine" drives the "p1 motor" to generate electricity, and the electrical energy generated by the "p1 motor" is mainly transmitted to the "p3 motor", and only the "p3 motor" drives the vehicle. The "engine" at this time is also known as the "range extender";
Hybrid parallel mode: At this time, the "p3 motor" and the "engine" are two-pronged, and the passion is exerted to drive the car together;
Kinetic energy recovery mode: When coasting or braking, the "wheel" drives the "p3 motor" to charge the "battery", compared to the "p1 motor" and the "p2 motor", the "p3 motor" has an advantage in the kinetic energy recovery project.
p1p3's electric architecture works in various working conditions and each component (click to enlarge)
The 5 connection modes are triggered under different operating conditions, and the components are in different working states (as shown in the table above), from which we can see these 2 characteristics:
1. The "p3 motor" is very busy: it is not driving the car alone, or it is driving the car jointly, anyway, it is not idle;
2. "p1 motor" is very "hybrid": when the system is in the "hybrid drive" working condition, the "p1 motor" generates electricity throughout the whole process, ensuring that the "p3 motor" has enough power.
Honda i-mmd hybrid system (Honda cr-v hybrid 2020)
Seeing this, I believe that friends who know something about hybrid technology have recognized this simple and simple "hybrid transmission" - "Honda i-mmd hybrid system" (intelligent multi mode drive). However, due to space limitations, we will not talk about its past and present lives today, and we will explain in detail in the following hybrid car brand series.
"Planetary Gears": A set of structures that have been played for decades
If the "Honda i-mmd hybrid system" has made people feel simple but not simple, then the "Toyota ths hybrid system" that has been mixed in the field of hybrid cars with the "e-cvt transmission" is another world of "hybrid transmission".
Basic structure diagram of the Toyota Prius (2nd generation) e-cvt transmission
The "e-cvt transmission", whose official full name is "electronically controlled electromagnetic clutch stepless transmission", is generally composed of two "motors", a "planetary gear set" and a set of "clutch". (As shown in the image above)
The connection logic of the planetary gear set
The most core component of the "e-cvt transmission" is a set of "planetary gear sets", which are mainly composed of three rotating components: "planetary gears", "sun gears" (or "sun wheels"), "planetary gear discs" (or "planetary racks") and "outer rings" (or "gear rings"). These three components are connected to the three major components of the power - the "engine" and the two "motors", and the connection logic is shown in the figure above.
Schematic diagram of the Toyota Prius (2nd generation) e-cvt transmission
The result of the "dynamic shunting" through the "planetary gear set" is:
"Engine": its power can be distributed to "wheels" and "p1 motors" through "planetary gear discs";
"p1 motor": mainly used for power generation, the generated electrical energy can be directly supplied to the "p3 motor" to drive the "wheel", or directly charge the "battery pack", or through the "solar gear" to start the "engine", etc.;
"p3 motor": The power generated by it can directly drive the "wheel" through the "outer ring gear" or charge the "battery pack" in reverse direction.
Basic working principle of Toyota ths (GIF)
Through 9 different operating conditions, let's take a look at how the "planetary gear set" is shunted. Note that the arrows in the following figure point to be easier to understand:
【Working condition 1: start】When the car gets the start command, the "battery pack" powers the "p1 motor" and starts the "engine";
【Working Condition 2: Idle Speed】After the "engine" starts, it starts to idle and drives the "planetary gear disc" to rotate in a positive direction. Since the "wheel" (connected to the "outer ring of gear") does not rotate, the forward rotation of the "planetary gear disc" (connected to the "engine") drives the "sun gear" (connected to the "p1 motor") through the "planetary gear". The "p1 motor" no longer receives the transmission of "battery pack", but instead becomes a "generator", which generates alternating current, and the "inverter" and "voltage converter" in the "pcu" (power control unit) turn ac power into low-voltage "direct current" to charge the "battery pack". In simple terms, the power of the "engine" at idle speed is all used to charge the "battery pack";
【Working condition 3: starting】When the car starts, the "battery pack" powers the "p3 motor", and the "p3 motor" drives the "wheel" (connected to the outer ring of gear) to start rotating in a positive direction, and the car moves forward slowly;
【Working condition 4: When there is a large torque demand】As the speed of the "p3 motor" increases, the speed of the "p1 motor" will also increase rapidly, and when the "p1 motor" is about to reach the upper limit, the "engine" actively intervenes in the power output at this moment. Usually, the harder you press the throttle at the start, the earlier the "engine" intervenes;
[Working condition 5: slow acceleration] When a certain speed is reached, if it continues to accelerate slowly, at this time, the "p3 motor" continues to be the main source of power, and the "engine" continues to operate in the low-speed range, which is similar to the power supply situation in the initial stage, but the working power of the "p3 motor" will be greater;
【Working condition 6: rapid acceleration】 When accelerating sharply, that is, the "full fire mode", the speed of the "engine" is increased into the efficient power output mode, driving the "p1 motor" to accelerate to provide stronger power for the "p3 motor", while the "engine" through the "planetary gear" and the "p3 motor" jointly output power to the "outer ring of gear", and finally drive the "wheel" to run at high speed;
【Working Condition 7: Uniform Speed】During high-speed cruising, the car is mainly driven by the "engine" because it reaches the efficient working area of the "engine". At this time, the "p3 motor" reverses the power supply to the "p1 motor", and then reverses the "solar gear" so that most of the power of the "planetary gear" is transmitted to the "outer ring of gear" to drive the car together. In simple terms, the "p3 motor" with the "p1 motor" adds bricks and tiles to the power output;
【Working condition 8: Deceleration】When decelerating, the "engine" is turned off, the "p1 motor" is idling, and the "p3 motor" is driven by the "wheel" for kinetic energy recovery;
【Working condition 9: reversing】The principle of reversing is similar to that of just starting, except that the "outer gear ring" operates in reverse under the action of the "clutch", the "battery pack" powers the "p3 motor", and the "p3 motor" drives the wheel to complete the reversing.
Toyota single row of planetary gears in different operating conditions
The working principle of "planetary gear set" is slightly complicated, it is recommended that you will compare the above charts to view, collect, like, one key three consecutive... Thank you~ In general, the "planetary gear set" is definitely the essence of the "Toyota ths Hybrid System".
Toyota Prius Plug-in Hybrid (2017) is equipped with a second-generation half-ths system
Due to space limitations, this chapter will not talk about the past and present lives of the "Toyota THS Hybrid System", but there is a tendency to be over-mythologized, and after that, we will start a single chat in the hybrid car brand series.
"p2.5 motor": confusing
Toyota e-cvt structure diagram (brief diagram)
Careful readers will find that the structure of the "Toyota THS Hybrid System" should not be classified as the "p1p3 motor architecture". Because from the definition of "p1 motor" (in front of the "clutch" after the "engine"), the "mg1 motor" in the "e-cvt transmission" is more like a "p2 motor", but from the role of the "mg1 motor", it is mainly used for power generation, and is not given the mission of directly driving the "wheel", which in turn meets the definition of the working content of the "p1 motor", so the "e-cvt transmission" can be said to be a variant of the "p1p3 motor architecture", more precisely, It is a special kind of "hybrid transmission".
Schematic diagram of SAIC edu hybrid system structure (brief diagram)
Coincidentally, when we introduced the "p2 motor" before, the "edu hybrid system" of the previous steam was used as an example, and the pedigree of its "p2 motor" was not so pure. Therefore, from the perspective of the overall structure, SAIC's "edu hybrid system" integrates the "p1 motor", "p2 motor" and the traditional "transmission", in a sense, it is also like Toyota's "e-cvt transmission", which has become another kind of "hybrid transmission".
The p2.5 motor is easy to confuse
Therefore, in order to incorporate this kind of "hybrid transmission" into the "px motor architecture" and make it easier for consumers to understand and remember, the concept of "p2.5 motor" (also known as "ps motor") was formed. But I hope that you will not be too entangled in this concept, but see the characteristics of these architectures, the next issue, we continue to talk about "p2.5 motor", remember to pay attention to me Oh ~ ~