A design matching method of an energy-saving and emission-reducing transmission of a variable-ratio heavy commercial vehicle

Abstract

This invention relates to the field of powertrain matching technology for heavy-duty commercial vehicles, specifically disclosing a design and matching method for a variable-gradient energy-saving and emission-reducing transmission for heavy-duty commercial vehicles. The method involves powertrain matching analysis for heavy-duty commercial vehicles; based on regulations, segmented market operating condition research, driving habit research, AMT shift characteristics, and engine characteristics, the engine operating conditions are analyzed and categorized into quasi-static and dynamic conditions; the transmission adopts a 2×3×2+1 arrangement structure; the transmission uses a 13-speed variable-gradient transmission, enabling the engine to adapt to either quasi-static or dynamic operating conditions; based on meeting user needs for power matching, this invention optimizes the transmission speed ratios to ensure the engine operates within its optimal fuel consumption and emission range during quasi-static conditions, thereby reducing overall vehicle fuel consumption and improving overall vehicle emission compliance; the engine reduces shift frequency, minimizes power interruptions, and enhances the customer's driving experience.

Description

Technical Field

[0001] This invention relates to the field of powertrain matching technology for heavy-duty commercial vehicles, specifically to a design and matching method for a variable-gradient energy-saving and emission-reducing transmission for heavy-duty commercial vehicles. Background Technology

[0002] The transportation sector accounts for approximately 11% of my country's total carbon emissions, with road transport accounting for about 87% of the transportation sector's total carbon emissions. Heavy commercial vehicles, in particular, account for 54% of road transport carbon emissions. Currently, most heavy commercial long-haul semi-trailer trucks still use 12-speed transmissions. These existing 12-speed transmissions have high shifting frequency and slow power response, resulting in high fuel consumption and emissions under dynamic operating conditions (vehicle climbing, starting, and acceleration), leading to poor economic efficiency.

[0003] Therefore, a design and matching method for a variable-speed heavy-duty commercial vehicle energy-saving and emission-reducing transmission is needed to solve the problems of high shift frequency, slow power response, high emissions, and poor economic efficiency of traditional 12-speed transmissions. Summary of the Invention

[0004] To address the problems existing in the prior art, the purpose of this invention is to provide a design and matching method for a variable-gradient heavy-duty commercial vehicle energy-saving and emission-reducing transmission.

[0005] The technical solution adopted by this invention to solve its technical problem is: a design and matching method for a variable-gradient heavy-duty commercial vehicle energy-saving and emission-reducing transmission, comprising the following steps:

[0006] S1. Powertrain matching analysis for heavy commercial vehicles;

[0007] S2. Based on regulations, segmented market operating condition research, driving habit research, AMT shift characteristics, and engine characteristics, the engine operating conditions are analyzed and classified into quasi-static operating conditions and dynamic operating conditions.

[0008] S3, the transmission adopts a 2×3×2+1 layout structure;

[0009] S4. The transmission adopts a 13-speed variable differential transmission, which allows the engine to adapt to both static and dynamic operating conditions. The 13-speed variable differential transmission uses a large differential of 1.28-1.30 between gears 1-12 and a small differential of 1.21-1.24 between gears 12-13.

[0010] Preferably, the powertrain matching analysis in step S1 includes fuel consumption standards, emission standards, CHTC detailed operating condition studies, customer operation data studies, and engine static and dynamic characteristics.

[0011] Preferably, the quasi-static operating condition in step S2 allows the engine to operate at its optimal speed and load. In the quasi-static operating conditions on flat ground and at high speeds, a small gear shift is used to control the speed and load. In the dynamic operating conditions, a large gear shift is used for climbing and acceleration to reduce the frequency of gear changes.

[0012] Preferably, the transmission in step S3 adopts a 2×3×2+1 arrangement structure, specifically as follows: the transmission includes a main gearbox, a front auxiliary gearbox, and a rear auxiliary gearbox. The gears in the main gearbox are all connected to the front and rear auxiliary gearboxes through drive shafts. The front auxiliary gearbox is connected to the input shaft, the rear auxiliary gearbox is connected to the output shaft, and an intermediate shaft is installed in the main gearbox.

[0013] Preferably, the front auxiliary box has a low-gear area and a high-gear area arranged in the first 2 of a 2×3×2+1 structure, with the high-gear gear in the high-gear area connected to the input shaft and the low-gear gear in the low-gear area connected to the high-gear gear through a transmission shaft; the rear auxiliary box has a low-gear area and a high-gear area arranged in the second 2 of a 2×3×2+1 structure, with the high-gear gear in the high-gear area connected to the output shaft and the low-gear gear in the low-gear area connected to the high-gear gear through a transmission shaft.

[0014] Preferably, the main gearbox is provided with a variable differential gear set, a reverse gear, a first pair of gears, a second pair of gears, and a third pair of gears. The variable differential gear set is arranged as 1 in a 2×3×2+1 structure. The variable differential gear set is used when driving the high-speed range of the front auxiliary gearbox and the rear auxiliary gearbox. The first pair of gears, the second pair of gears, and the third pair of gears are arranged as 3 in a 2×3×2+1 structure.

[0015] Preferably, in step S4, the 13-speed variable differential transmission is matched with a dynamic operating condition delay shift speed strategy in gears 1-12; and a quasi-static operating condition speed reduction and load adjustment shift strategy is matched in gears 12-13.

[0016] The present invention has the following beneficial effects:

[0017] The design and matching method of the variable-gradient heavy-duty commercial vehicle energy-saving and emission-reducing transmission of the present invention optimizes the transmission speed ratio to keep the engine in the optimal fuel consumption and emission range when it is working under quasi-static conditions, based on the premise of meeting the power matching of users, thereby reducing the overall vehicle fuel consumption and improving the overall vehicle emission compliance.

[0018] The present invention relates to a design and matching method for a variable-gradient heavy-duty commercial vehicle energy-saving and emission-reducing transmission. Based on the existing 12-speed transmission, the transmission differential and speed ratio of the 1st to 11th gears are increased (to improve maximum gradeability, starting, and acceleration power). The speed ratio of the 12th direct gear remains unchanged at 1.0. At the same time, a small differential gear is added to create a 13-speed variable-gradient transmission. This reduces the frequency of engine shifting, reduces power interruption, and improves the customer's power experience during starting, climbing, and acceleration.

[0019] The design and matching method of the variable-gradient heavy-duty commercial vehicle energy-saving and emission-reducing transmission designed in this invention, through theoretical calculation and analysis, market big data statistics and experimental verification, effectively improves the R&D efficiency of transmission manufacturers and ensures the reliability of products to the greatest extent. Attached Figure Description

[0020] Figure 1 This is a flowchart of the design and matching method for energy-saving and emission-reducing transmissions for heavy-duty commercial vehicles with variable-gradient transmissions.

[0021] Figure 2 This is a schematic diagram of the CHTC-TT operating cycle for heavy-duty commercial semi-trailer tractors.

[0022] Figure 3 This is a simplified layout diagram of a 13-speed variable-gradient transmission (2×3×2+1 structure).

[0023] Figure 4 This is a schematic diagram of the quasi-static universal characteristics of an engine.

[0024] Figure 5 This is a schematic diagram of engine thermal management.

[0025] Figure 6 This is a schematic diagram of the engine's dynamic characteristics.

[0026] Figure 7 This is a diagram showing the gear distribution of the number of gear shifts from 1 to 12 in the CHTC working condition when a heavy-duty tractor is matched with the original 12-speed transmission.

[0027] Figure 8 This is a diagram showing the engine landing point distribution for gears 1-11 in the CHTC operating condition of the original 12-speed transmission.

[0028] Figure 9 This is a diagram showing the engine landing point distribution for the 12th gear in the CHTC operating condition, which is matched with the original 12-speed transmission.

[0029] Figure 10 This is a diagram showing the gear distribution of a heavy-duty tractor truck equipped with a 13-speed transmission under CHTC operating conditions, from gears 1 to 13.

[0030] Figure 11 This is a diagram showing the engine landing point distribution for gears 1-11 in CHTC condition when matched with a 13-speed transmission.

[0031] Figure 12 This is a diagram showing the engine landing point distribution in gears 12-13 of the CHTC operating condition when matched with a 13-speed transmission.

[0032] Figure 13 This is a diagram showing the maximum gradeability of each gear in the original 12-speed transmission for heavy-duty tractor trucks.

[0033] Figure 14This is a diagram showing the maximum gradeability of each gear in a 13-speed transmission for a heavy-duty tractor truck.

[0034] Figure 15 This is an acceleration curve of a heavy-duty commercial tractor truck from 0 to 80 km / h, compared to the original 12-speed transmission and the new 13-speed transmission with variable speed differential. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] like Figures 1-15 As shown, a variable-gradient heavy-duty commercial vehicle transmission design, based on meeting the power matching requirements of users, optimizes the transmission speed ratio to keep the engine in the optimal fuel consumption and emission range as much as possible when operating under quasi-static conditions, while reducing the frequency of gear shifts, reducing power interruption, improving the customer's power experience, and reducing dynamic fuel consumption under dynamic conditions.

[0037] The transmission of this invention increases the gear ratio and speed difference of gears 1-11 (improving maximum gradeability, starting, and acceleration power), while keeping the 12th gear direct gear ratio of 1.0 unchanged. At the same time, a small differential gear is added, making it a 13-speed variable differential transmission. This reduces the frequency of engine shifts, reduces power interruption, improves the customer's power experience, and reduces dynamic fuel consumption and emissions during starting, climbing, and acceleration. It also keeps the engine in its optimal fuel consumption and emission operating range to the greatest extent possible during high speeds, good road conditions, and cruise control.

[0038] The 13-speed differential gearbox adopts a 2×3×2+1 layout structure. The specific distribution of the 2×3×2+1 layout structure is as follows: the gearbox includes a main gearbox, a front auxiliary gearbox, and a rear auxiliary gearbox. The gears in the main gearbox are all connected to the front and rear auxiliary gearboxes through drive shafts. The front auxiliary gearbox is connected to the input shaft, and the rear auxiliary gearbox is connected to the output shaft. An intermediate shaft is installed in the main gearbox.

[0039] The front auxiliary gearbox has a low-gear zone and a high-gear zone arranged in the first 2×3×2+1 configuration. The high-gear gear in the high-gear zone is connected to the input shaft, and the low-gear gear in the low-gear zone is connected to the high-gear gear through the drive shaft. The rear auxiliary gearbox has a low-gear zone and a high-gear zone arranged in the second 2×3×2+1 configuration. The high-gear gear in the high-gear zone is connected to the output shaft, and the low-gear gear in the low-gear zone is connected to the high-gear gear through the drive shaft.

[0040] The main gearbox is equipped with a variable differential gear set, a reverse gear, a first pair of gears, a second pair of gears, and a third pair of gears. The variable differential gear set is the 1st in the 2×3×2+1 arrangement structure. The variable differential gear set is used when driving the high-speed zone of the front auxiliary gearbox and the rear auxiliary gearbox. The first pair of gears, the second pair of gears, and the third pair of gears are the 3rd in the 2×3×2+1 arrangement structure.

[0041] The 13-speed variable differential transmission uses a dynamic operating condition delay shift speed strategy in gears 1-12; and a quasi-static operating condition speed reduction and load adjustment shift strategy in gears 12-13.

[0042] The transmission design and matching method is based on AVL CRUISE software to establish a new power matching framework under the same CHTC regulations for heavy-duty commercial semi-trailer tractors. The analysis is then performed and compared with the simulation and test results of the original configuration.

[0043] Since the powertrain configuration of this invention is an optimized analysis of existing vehicle configurations, it not only shortens the development time for transmission manufacturers but also meets the requirements for reducing fuel consumption and emissions, thereby increasing the competitiveness of vehicle manufacturers.

[0044] A variable-gradient heavy-duty commercial vehicle transmission design, based on meeting the power matching requirements of users, optimizes the transmission speed ratio to keep the engine in the optimal fuel consumption and emission range during quasi-static operation, while reducing the frequency of gear shifts and power interruption during dynamic operation. This effectively improves the customer's power experience, reduces the dynamic fuel consumption of the vehicle, and also increases the pass rate of the vehicle's emission compliance.

[0045] This invention improves starting, acceleration, and hill-climbing performance (by increasing the gear ratios of 1st to 11th gears), combines engine dynamics and near-static optimal fuel efficiency and emission range speeds, and adjusts the transmission gear ratios for preset parameters.

[0046] 1. Optimize the operating speed and load range of the quasi-static engine: (Reference) Figure 2 , Figure 4 , Figure 5 , Figure 9 , Figure 12 According to GB / T 38146.2 CHTC cycle curve (see...) Figure 2 The high-speed cycle corresponding to the tractor vehicle in the ) is a vehicle speed ≥ 60 km / h, corresponding to the engine's main operating range of 1000~1400 rpm / 700~1400 Nm. Figure 9 (Original plan). Matching with a 13-speed transmission reduces the engine's operating speed range by 50-150 rpm, increasing torque by approximately 200 Nm, to 950-1250 rpm / 900-1600 Nm. Figure 12The new design focuses more on the engine's optimal operating range, reducing engine thermal management and lowering fuel consumption.

[0047] 2. Combining Figure 6 During engine dynamics, a low excess air coefficient leads to incomplete combustion and poor fuel consumption. Increasing the shift point difference between gears 1-12 results in a shift count of 104 times under the CHTC cycle. Figure 7 The original plan was reduced to 78 times. Figure 10 The new design significantly reduces gear shifting frequency, minimizing the engine's entry into dynamic mode, although the average engine speed range during dynamic operation increases slightly by 82 rpm. Figure 8 Original plan, Figure 11 (New solution), but it can also effectively reduce energy consumption and emissions;

[0048] 3. Heavy-duty commercial tractor trucks equipped with a 13-speed variable differential transmission have a maximum gradeability increase of 0.19% to 19.92% in gears 1-11. Figures 13-14 The customer's driving experience and power performance are significantly improved; acceleration performance from 0 to 80 km / h is also better. Figure 15 The acceleration time is shortened by 3.5 seconds.

[0049] 4. This invention is based on an existing 12-speed transmission, increasing the gear ratios and speed differences between gears 1-11 (improving maximum gradeability, starting performance, and acceleration). The 12-speed direct drive ratio remains unchanged at 1.0. Simultaneously, a small differential gear is added, creating a 13-speed variable differential transmission. This 13-speed variable differential transmission adopts a 2×3×2+1 arrangement, with two sets of gear ratios (low and high gear ranges) in the front / rear auxiliary gearboxes, three pairs of main forward gears in the main gearbox, and one additional set of variable differential gears. Figure 3 The main gearbox of the transmission is equipped with an additional set of differential gears that lock in the low gear range of the front and rear auxiliary gearboxes.

[0050] 5. The variable gear ratio scheme is as follows: the gear ratio between 1st and 12th gears is 1.295±0.02, and the gear ratio between 12th and 13th gears is a smaller ratio of 1.210±0.02. The first gear ratio of the 13th gear variable gear ratio is increased to 17.111, and the highest gear ratio is 0.826. The gear ratios are shown in Table 1 below:

[0051] Table 1: Gear Ratio Table for a 13-Speed ​​Transmission

[0052]

[0053] The main line speed is shown in Table 2 below:

[0054] Table 2:

[0055] Forward gear Pair 1 The second pair The 3rd pair Variable differential gear set Main gearbox speed ratio distribution 2.812 1.677 1.0 0.826

[0056] The speed ratios of the front auxiliary box and the rear auxiliary box are shown in Table 3 below:

[0057] Table 3:

[0058]

[0059] Reverse gear speeds are shown in Table 4 below:

[0060] Table 4:

[0061] Reverse gear R1 R2 Reverse gear ratio 13.448 2.852

[0062] This invention relates to a variable-gradient heavy-duty commercial vehicle transmission. By optimizing the transmission ratios, it maximizes the engine's operating range for optimal fuel consumption and emissions during quasi-static operation, while reducing shift frequency, minimizing power interruptions, improving the customer's driving experience, and lowering dynamic fuel consumption during dynamic operation. Based on an existing 12-speed transmission, the transmission ratios and gear ratios of gears 1-11 are increased (improving maximum gradeability, starting performance, and acceleration). The 12th direct drive ratio remains unchanged at 1.0, while a small differential gear is added. The gear ratios of gears 1-12 are 1.295±0.02, and gears 12-13 use a small differential between 1.210±0.02. The 13th gear variable-gradient transmission's first gear ratio is increased to 17.111, and the highest gear ratio is 0.826.

[0063] This invention primarily designs a variable-gradient heavy-duty commercial vehicle transmission and analyzes its application in the market conditions of heavy-duty commercial semi-trailer tractors. It focuses on research into driving habits, AMT shifting characteristics, engine universal characteristics, and engine static / dynamic characteristics, while also incorporating interpretations of GB17691 (China VII emission standards) and GB30510 (Fourth Stage) fuel consumption regulations. To maximize engine efficiency and emissions control during quasi-static operation, and to reduce shifting frequency, power interruption, and driving experience during dynamic operation, while minimizing dynamic fuel consumption, a variable-gradient transmission technology solution with a 2×3×2+1 layout for heavy-duty long-haul tractors and other market segments was developed. The main gearbox / front and rear auxiliary gearboxes and gear ratios were designed. After the vehicle is equipped with the new powertrain, the engine speed is effectively concentrated in the optimal dynamic and static operating ranges, reducing dynamic shifting frequency, improving power performance, and achieving energy saving, emission reduction, and an enhanced driving experience.

[0064] This invention is not limited to the above-described embodiments. Anyone should know that any structural changes made under the guidance of this invention, and any technical solutions that are the same as or similar to this invention, fall within the protection scope of this invention.

[0065] The technologies, shapes, and structures not described in detail in this invention are all known technologies.

Claims

1. A design and matching method for a variable-gradient heavy-duty commercial vehicle energy-saving and emission-reducing transmission, characterized in that, Includes the following steps: S1. Powertrain matching analysis for heavy commercial vehicles; S2. Based on regulations, segmented market operating condition research, driving habit research, AMT shift characteristics, and engine characteristics, the engine operating conditions are analyzed and classified into quasi-static operating conditions and dynamic operating conditions. S3, the transmission adopts a 2×3×2+1 layout structure; S4. The transmission adopts a 13-speed variable differential transmission, which allows the engine to adapt to both static and dynamic operating conditions. The 13-speed variable differential transmission uses a large differential of 1.28-1.30 between gears 1-12 and a small differential of 1.21-1.24 between gears 12-13.

2. The design and matching method for a variable-gradient heavy-duty commercial vehicle energy-saving and emission-reducing transmission according to claim 1, characterized in that, The powertrain matching analysis in step S1 includes fuel consumption standards, emission standards, CHTC detailed operating condition studies, customer operation data studies, and engine static and dynamic characteristics.

3. The design and matching method for a variable-gradient heavy-duty commercial vehicle energy-saving and emission-reducing transmission according to claim 2, characterized in that, In step S2, the quasi-static operating condition allows the engine to operate at its optimal speed and load. In the quasi-static operating conditions on flat ground and at high speeds, a small gear difference is used to control the speed and load. In the dynamic operating conditions, a large gear difference is used for climbing and acceleration to reduce the frequency of gear shifting.

4. The design and matching method for a variable-gradient heavy-duty commercial vehicle energy-saving and emission-reducing transmission according to claim 1, characterized in that, The transmission in step S3 adopts a 2×3×2+1 arrangement structure, specifically as follows: the transmission includes a main gearbox, a front auxiliary gearbox, and a rear auxiliary gearbox. The gears in the main gearbox are all connected to the front and rear auxiliary gearboxes through drive shafts. The front auxiliary gearbox is connected to the input shaft, and the rear auxiliary gearbox is connected to the output shaft. An intermediate shaft is installed in the main gearbox.

5. The design and matching method for a variable-gradient heavy-duty commercial vehicle energy-saving and emission-reducing transmission according to claim 4, characterized in that, The front auxiliary gearbox has a low-gear zone and a high-gear zone arranged in a 2×3×2+1 configuration, which is the first "2". The high-gear gear in the high-gear zone is connected to the input shaft, and the low-gear gear in the low-gear zone is connected to the high-gear gear through a transmission shaft. The rear auxiliary gearbox has a low-gear zone and a high-gear zone arranged in a 2×3×2+1 configuration, which is the second "2". The high-gear gear in the high-gear zone is connected to the output shaft, and the low-gear gear in the low-gear zone is connected to the high-gear gear through a transmission shaft.

6. The design and matching method for a variable-gradient heavy-duty commercial vehicle energy-saving and emission-reducing transmission according to claim 5, characterized in that, The main gearbox is equipped with a variable differential gear set, a reverse gear, a first pair of gears, a second pair of gears, and a third pair of gears. The variable differential gear set is arranged as 1 in a 2×3×2+1 structure. The variable differential gear set is used when driving the high-speed zone of the front auxiliary gearbox and the rear auxiliary gearbox. The first pair of gears, the second pair of gears, and the third pair of gears are arranged as 3 in a 2×3×2+1 structure.

7. The design and matching method for a variable-gradient heavy-duty commercial vehicle energy-saving and emission-reducing transmission according to claim 1, characterized in that, In step S4, the 13-speed variable differential transmission is matched with a dynamic working condition delay shift speed strategy in gears 1-12; and a quasi-static working condition speed reduction and load adjustment shift strategy is matched in gears 12-13.

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