On September 17, the world's largest and most influential commercial vehicle exhibition, the 2024 Hannover International Commercial Vehicle Show (IAA) in Germany, officially opened. "Laymen look at the lively, insiders look at the doorway", in the auto show, the influence and attractiveness of the whole vehicle is often greater than the parts. However, in terms of real technical content, parts are higher than the whole vehicle. At this year's Hannover Motor Show, Weichai showcased Euro VII diesel, hybrid, flex-fuel internal combustion engine platforms and hydrogen fuel cell power systems, fully demonstrating Weichai's technical strength in the field of commercial vehicle power with dazzling products. Through detailed research and analysis of Weichai's hybrid products, Shangchebang will analyze its application scenarios and core competitiveness.
Recently, Shangchebang conducted a detailed investigation of the current situation of technology, policy and practical application of domestic hybrid and range extender trucks, and published an article entitled "Why Hybrid and Range Extender Cannot Become the Mainstream of the Truck Market", which has attracted the attention of the majority of readers. There is no problem with the hybrid technology route itself, but there are many problems in the process of application in the truck field, for example, the company that takes the lead in actively promoting the commercialization of hybrid trucks is a transmission company and an electric motor company, rather than an engine company or a vehicle company. The key to whether hybrid trucks can be commercialized and applied lies in scenarios and working conditions, and in terms of data accumulation and data application in scenarios and working conditions, transmission companies and motor companies are much lower than engine companies and vehicle companies. Shangchebang believes that the powertrain hardware (including the engine, motor, and gearbox) is the "body", and the software calibration (including weight recognition, scene recognition, and coping strategies) is the "soul", and the two must be closely integrated to achieve the best energy-saving effect.
It is inevitable for the development of the industry that the powertrain enterprises represented by Weichai will lead and promote hybrid technology, because Weichai has inherent advantages in the accumulation of data and data application in scenarios and working conditions. In this Hannover Motor Show, Weichai focused on the WP14T-DHT heavy-duty hybrid assembly, at the same time, Weichai has also developed WP2.3Q-138, WPH8-357 two hybrid products, these three products fully cover 4.2 tons of light trucks, 25 tons or 31 tons of mixer trucks, dump trucks, special vehicles, and 42 or 49 tons of heavy truck tractor application scenarios.
01
面向长途干线运输场景：WP14T-DHT
The engine of this hybrid powertrain is a WP14T610E62 engine with a displacement of 13.5 liters, a maximum horsepower of 610 horsepower, a maximum torque of 2750 Nm, and a maximum torque range of 900-1400 r/min. This engine is a very energy-saving high-horsepower engine in the field of heavy trucks, which can meet the high speed of the vehicle with a total weight of 49 tons and a speed of 90 km/h, and its fuel consumption can be controlled at 26-28 liters / 100 km; The drive motor has a rated power of 130 kW (176.8 hp) and a peak power of 200 kW (272 hp). The generator motor has a rated output of 65 kW (88.4 hp) and a peak power of 130 kW (176.8 hp), a double-planetary structure with no clutch to eliminate frustration in various drive modes, and a power battery capacity of 60 kWh.
This WP14T-DHT hybrid powertrain is mainly used in the long-distance trunk transportation market, the key to the profitability of long-distance trunk transportation vehicles lies in timeliness, and the most affecting timeliness and fuel consumption of the working condition is long-distance climbing, WP14T-DHT in this application scenario The technical advantages are as follows.
1. When climbing over long distances, the drive motor has a rated power of 130kW (176.8 horsepower), a power battery capacity of 60kWh, and an optimal power usage of 42kWh, the drive motor can work for 19 minutes, and the vehicle can climb a long distance of 70km/h with a slope of 4%, then it can travel 22.6 kilometers with a drop of 900 meters. At this time, the engine speed only needs to be controlled at 1400r/min (the maximum speed in the maximum torque area), and the engine is still in the optimal fuel consumption area to exert the maximum fuel saving effect.
2. When going downhill for long distances, the dual-motor brake recovery efficiency is higher, and it can also play the role of "hydraulic retarder". Assuming that the braking power of the dual motor is 150kW (204 horsepower), plus the engine braking power of 400 horsepower, the vehicle can meet the vehicle to go downhill at a constant speed of 80km/h, and at the same time, the power of the power battery can be fully charged.
3. Under different speeds and driving scenarios, the working mode can be intelligently switched, including pure electric mode, series mode, parallel mode, and direct drive mode to ensure power and economy. On some road sections, the vehicle can travel about 16 kilometers in pure electric mode; It adopts direct drive mode on straight highways and cruises at a speed of 90 km/h. It is reported that this WP14T-DHT hybrid powertrain can achieve 25% fuel saving under regulatory working conditions.
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For engineering and special vehicle scenarios: WPH8-357
The engine of this hybrid assembly uses WP8.350E62 engine, with a displacement of 7.8 liters, a maximum horsepower of 350 horsepower, a maximum torque of 1400 Nm· meters, and a maximum torque range of 1200-1600r/min; The drive motor has a power rating of 100 kW (136 hp) and a peak power of 200 kW (272 hp) in a P2 arrangement between the engine and gearbox; The transmission is a 12AMT automatic transmission with a battery capacity of 62.16 kWh. Theoretically speaking, mixer trucks, dump trucks, and special vehicles are most suitable for using hybrid technology in scenarios and working conditions, but up to now, there are few corresponding hybrid trucks in China, because the hardware matching and software calibration of hybrid powertrains are greatly increased due to the complexity of the scenarios.
Driving at a constant speed on a 4-axle 31-ton standard load and straight road, the mainstream mixer trucks, dump trucks, and special vehicles all use engines of about 8.5 liters, and their power can meet the requirements. But after heavy loads, it is necessary to start frequently, accelerate, and brake on urban roads; When entering and exiting the construction site, the road conditions are very poor, and you need to slam the throttle to pass at a high speed; In some construction sites, after the pit (20 meters, 5 floors underground) is fully loaded, and the steep slope of 30% is climbed to reach the ground, it is necessary to "hang 1st gear + floor throttle" to pass. Weichai's WPH8-357 hybrid total achievement fully considers the above scenarios and working conditions, and the specific technical advantages are as follows.
1. Frequent starting and acceleration on urban roads is the most fuel-consuming stage of the engine. At this time, the electric motor outputs at a peak power of 200kW (272 horsepower), and the engine only needs to reach 1000-1200r/min, which is in the best fuel consumption area to achieve the effect of fuel saving. Since the power of the power battery is 62.16 kWh, the optimal power usage is 43.5 kWh, which can meet the electric motor to work at peak power for about 13 minutes. According to the actual test, the mixer truck and dump truck only need the electric motor to output 1 minute of peak power for each acceleration, so it can meet the starting acceleration of the vehicle about 13 times.
2. For frequent braking on urban roads, which is a huge waste of energy, the motor is converted into a generator, which can recuperate energy and reduce the wear of brake pads.
3. In bad road conditions and extreme climbing, the vehicle needs to drive in the way of "hanging 1st gear + floor throttle", which is also the most fuel-consuming state of the engine. At this time, the motor can output at peak power for 6-8 minutes (the motor will cause high temperature torque limiting due to the peak power output for a long time), and the maximum output power of the entire hybrid assembly is 485 horsepower, which can meet the needs of mixer trucks and dump trucks in the worst working conditions.
4. In some specific areas, it is required to drive in pure electric mode, then the motor can drive for 26 minutes with a rated power of 100kW (136 horsepower), and the vehicle can travel 21.75 kilometers at a constant speed of 50km/h. At present, hybrid heavy trucks can have green plates in many places and enjoy the right of way discount for new energy vehicles. In contrast, the selling price of hybrid mixer trucks and dump trucks is much lower than that of 423 kWh electric heavy trucks, which can significantly reduce the cost of ownership for customers.
At present, the battery power of many hybrid heavy trucks in China is only 15kWh, and the hardware matching of engine, motor and battery capacity is unreasonable. In contrast, Weichai fully investigated the scenarios and working conditions of mixer trucks and dump trucks, and the hardware matching of WPH8-357 hybrid assembly is more reasonable, the software calibration is more accurate, the power is increased by 11.6%, the fuel saving is 20%-25%, and the fuel consumption under legal working conditions is less than 35 liters/100 kilometers.
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For light commercial vehicle application scenarios: WP2.3Q-138
The engine of this hybrid powertrain is WP2.3Q140E62 engine, with a displacement of 2.3 liters, a maximum horsepower of 140 horsepower, and a national VIB emission standard, with a thermal efficiency increase of 1.0%; The drive motor is rated at 35 kW (47.6 hp) and 70 kW (95.2 hp) with a peak power of 70 kW (95.2 hp) and is arranged in a P2 arrangement between the engine and the gearbox, while the transmission is equipped with a 6AMT automatic transmission with a power battery capacity of 15.45 kWh. This hybrid powertrain has a weight sensing function, which can judge the total weight of the vehicle according to the output torque and acceleration time of the vehicle during the acceleration process, and the angle sensor can judge whether the vehicle is in an uphill or downhill state, and the intelligent calibration strategy based on the actual road conditions ensures that the engine is in the optimal fuel consumption range under common working conditions, and finally can achieve 20% fuel saving under legal working conditions. The specific technical advantages are as follows.
1. In the uphill working conditions of hilly and mountainous roads, the vehicle ECU can automatically distribute the output power of the engine and motor according to the required power of the wheel end drive according to the vehicle weight, ramp angle, driving speed and other parameters, the power battery capacity is 15.45kWh, and the optimal range for actual use is 90%-20% SOC, which is 10.8kWh. Assuming that the motor is output at a rated power of 35kW (47.6 hp), it can last for 18 minutes. Based on a climbing speed of 45 km/h, the vehicle can travel about 13.9 kilometers uphill. During the whole uphill process, the engine speed is in the middle of the maximum torque range, which is the efficient fuel-saving interval of the engine, so the uphill electric motor assistance is the key to hybrid fuel saving.
2. In downhill conditions, the motor is converted into a generator, which converts potential energy into electrical energy, and also plays the role of "electromagnetic retarder" to improve the safety of the vehicle. In addition, the vehicle does not need to install a water tank and a water shower system, which reduces the weight of the whole vehicle.
With the release of the WP14T-DHT at the Hannover Motor Show, it is expected that Weichai's three hybrid powertrains will be matched and applied in domestic truck products. Shangchebang believes that Weichai's leading and promotion of hybrid technology will promote the application of hybrid truck technology in China and continuously increase the market share of hybrid trucks. (Note: Some of the data in the article are derived and calculated by Shangchebang according to the empirical formula, and the final actual data is subject to the official announcement of Weichai.) ）