Can you stand an article that will help you understand the EM-P of Lectra？

With the increasing trend of electrification, unlike traditional fuel vehicles, the power structure of new energy vehicles is more complex and changeable, almost a brand and a structure, such as Geely Hi·P, BYD DM-i and so on. A hundred flowers blossom, which may be to describe the current hybrid car market. Therefore, as a fan of Lectra 03, I naturally became interested in the current hybrid technology of Lectra brand. I believe that friends who don’t know much about hybrid but prefer Lectra brand also have many questions. For example, what does the P1+P3+P4 motor scheme adopted by Lectra EM-P high-end models mean now? Is it good or not? Don’t worry, an article will give you the answer.

Looking at all the models currently on sale at Lectra, except for Lectra 01 and Lectra 03 and EM-F hybrid models with blue brand, all other hybrid models adopt EM-P plug-in hybrid drive with green brand.

What is "Px Hybrid"?

And if you want to understand the LECK EM-P, you must first understand the "Px hybrid". In fact, the term "Px hybrid" refers to the position of the motor. At the same time, different positions will also affect the connection between the motor and the gearbox, and will also change the parallel or series-parallel connection between the gearbox and the motor. P here means position. For the single-motor hybrid power system, according to the position of the motor relative to the traditional power system, the single-motor hybrid schemes can be divided into five categories, named P0, P1, P2, P3 and P4 respectively.

So knowing the concept of "Px hybrid", is it good to lead the hybrid architecture of EM-P? We will analyze them one by one.

The first is P1, whose motor position is in front of the gearbox and installed on the crankshaft of the engine, that is, the original flywheel position. The engine crankshaft acts as the rotor of ISG motor, so it also supports engine start-stop and braking energy recovery to generate electricity. Therefore, the transmission efficiency of P1 layout with mechanical connection will be much higher.

But it is P3 and P4 that really start to feel "pure electricity". The former is integrated in the back end of DHT-that is to say, P3 is essentially an EV direct driver. P4 is only related to the rear axle, which is a common "rear motor" for pure electric vehicles. It will be directly mounted on the rear axle of the vehicle and directly act on driving the rear wheels. Its main purpose is to realize four-wheel drive and energy recovery. Moreover, the motor and the engine are actually coupled through the ground, and although its working properties are similar to other simple parallel connections, there is no mechanical connection inside the vehicle.

What is the layout of lectra EM-P?

After reading the principles, advantages and disadvantages of three different motor positions, let’s talk back to Lectra. In fact, the layout of P1+P3+P4 adopted by LEEK EM-P is only adopted by LEEK 08 and LEEK 09, while LEEK 01PHEV just released some time ago adopts LEEK’s unique "P2.5 architecture", and its officially claimed "P2.5 architecture" should be similar to P3, but technically speaking, it should be an upgraded version of P2. Its motor is not directly connected with the input shaft of the dual-clutch gearbox, but connected with the input shaft in charge of gears 2, 4, 6 and R, which can be regarded as improving the impact of oil-electricity connection and avoiding many technical problems of P2 and P3 with higher integration.

Let’s take a look at the advantages of the third DHT gear of the tram. In fact, the gear setting of the third gear DHT of the tram is similar to that of the oil truck. When the vehicle is driving in the high-speed range, the torque of the single gear is insufficient, and the three-gear DHT model can improve the torque of the vehicle by adjusting the gear, so that it can still drive in the high-speed range calmly. Then why do so many car companies still insist on using single-gear DHT? This is because the hybrid structure itself is more complicated, and it is difficult to realize the hybrid structure of some car companies by adding the transmission system in a limited space.

Is lectra EM-P the leading hybrid architecture?

Having said so much about the technical application of Lexus, you may not have much idea. Let’s talk about what EM-P models can bring us in daily driving. Let’s take the 2023 LECK 08EM-P four-wheel drive performance Halo version as an example. It adopts the layout of P1+P3+P4. In the most common urban commuting road conditions, such a car scene can be driven in pure electric mode. The battery life of CLTC 220km is enough for most people to charge in 3-4 days. In pure electric mode, only the motor drives the vehicle, which has exactly the same driving experience as a pure tram.

When our vehicle speed is above 88km/h, the engine will be involved in driving. It can be said that this set of EM-P hybrid, while driving close to the pure tram in daily life, also has the endurance far beyond the pure tram. When the vehicle needs to start quickly from a static state, the ejection start mode of this system can also be completed by making the engine and P1, P3 and P4 motors work together and accelerating at 0-100km/h for 4.6 seconds. When the vehicle drives to the elevated or loop, the system will judge whether the engine is involved according to the driver’s power request. When the driver needs to overtake, DHT Evo transmission can downshift, increase the torque of the engine and help the vehicle overtake quickly. On the highway cruising at 120km/h, EM-P will give priority to engine direct drive. Compared with the insertion and mixing of single gear, DHT Evo is more calm and has gears available. At present, Lectra EM-P is a leading hybrid structure in the industry.

Therefore, we can sum up the advantages of Lectra EM-P in one sentence: it lasts longer than pure trams, is stronger than ordinary hybrid cars, and is more energy-saving than extended-range cars. Finally, answer another question-how does Lectra EM-P compare with BYD DM-i? If we want to compare the two, because EM-P uses a 3-speed DHT hybrid special gearbox, and the hybrid structure is more complicated, while DM-i can only drive directly in a single gear, so it is more advantageous to overtake EM-P in a high-speed range. After all, 3-speed DHT is adopted. Disadvantages: Theoretically, the failure rate of EM-P may be higher than that of DM-i with simple structure, but this is only in theory. After all, there is no report on the failure of Lectra EM-P power system, which shows that its stability is also very good.