Oil-electric hybrid power system for medium and large passenger and freight vehicles

Abstract

The application discloses an oil-electricity hybrid power system for medium and large-sized passenger and freight vehicles, wherein the output end of a driving motor / generator on a hybrid power gearbox is in transmission connection with the input end of a gear reducer, the output end of the gear reducer is in transmission connection with an input shaft, a fuel / gas engine is in cooperation with a clutch to drive the input shaft, the input shaft drives an intermediate shaft through a one-stage three-gear transmission, and the intermediate shaft drives an output shaft through a two-stage four-gear transmission to drive the rear axle of the vehicle to run. When the vehicle runs at a medium or low speed, the driving motor / generator is powered by a power battery to drive the vehicle to run, and the problem of low engine efficiency when the power demand is small can be avoided. When the vehicle runs at a medium or high speed, the fuel / gas engine is started to drive the vehicle, and when the vehicle accelerates or climbs, the driving motor / generator can assist the engine to drive the vehicle, so that the power performance and fuel / gas economy of the vehicle are greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of transportation technology, specifically relating to a hybrid electric power system for medium and large passenger and freight vehicles. Background Technology

[0002] Existing large and medium-sized passenger and freight vehicles primarily use gasoline / gas engine power systems, with some short-distance freight trucks or city buses using electric power systems. Vehicles powered by gasoline / gas engines generally suffer from weak power, poor acceleration and climbing ability, especially struggling to climb long inclines at high speeds, and insufficient braking capacity, particularly on long downhill sections at high speeds, which is dangerous. At low speeds, the engine load is low, resulting in low engine efficiency and poor fuel economy, while braking downhill also wastes a significant amount of energy. Electric power systems, limited by battery capacity and technology, result in insufficient range, limiting their application to short-distance freight trucks or city buses, and making them unsuitable for long-distance large passenger and freight vehicles.

[0003] Therefore, we propose a hybrid electric vehicle system for medium and large passenger and freight vehicles to solve the problems mentioned in the background section. Summary of the Invention

[0004] The purpose of this invention is to provide a hybrid electric power system for medium and large passenger and freight vehicles to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a hybrid electric vehicle system for medium and large passenger and freight vehicles, comprising a central controller, a fuel / gas engine, a clutch, a hybrid transmission, a power battery, and an air-cooled power radiator. The output end of the drive motor / generator on the hybrid transmission is connected to the input end of a gear reducer. The output end of the gear reducer is connected to the input shaft. The fuel / gas engine, in conjunction with the clutch, drives the input shaft. The input shaft drives an intermediate shaft through a single-stage three-speed transmission. The intermediate shaft drives an output shaft through a two-stage four-speed transmission. The single-stage three-speed transmission, through its speed multiplication, forms a total of 12 gears across three gear ranges, thereby driving the main reducer gear pair and differential on the rear axle, and driving the drive wheels to rotate the front wheels, thus propelling the vehicle.

[0006] The hybrid transmission also includes a sun gear, an external ring gear, planetary gears, and a planetary gear carrier. The lowest gear of the three-speed transmission in the hybrid transmission uses a planetary gear reducer. The sun gear of the planetary gear reducer is coaxially fixed with the driven gear of the intermediate gear. The external ring gear is fixed to the housing of the hybrid transmission. The planetary gear carrier, which has planetary gears installed, engages with the intermediate shaft through a synchronizer. After the driven gear of the second gear has already been reduced in speed, it is further reduced in speed by the planetary gear reducer to form the lowest gear.

[0007] During gear shifting, the hybrid transmission disengages the clutch, the drive motor / generator adjusts its speed, and the gear shift is performed via a shift synchronizer. In addition to clutch disengagement, the hybrid transmission adjusts the speed of the drive motor / generator to bring the rotational speeds of the shift synchronizer and the corresponding gears closer together, allowing for smooth gear shifting through the engagement of the shift synchronizer.

[0008] The central controller is electrically connected to the drive motor / generator, power battery, air-cooled power radiator and fuel / gas engine respectively. The drive motor / generator is determined by the central controller based on factors such as the current vehicle driving conditions, power battery charge, and driver power demand. It can drive the vehicle alone or in conjunction with the engine. It can also switch to generator to generate electricity to brake the vehicle when the engine has surplus power or when the vehicle is decelerating or going downhill, and store the electricity in the power battery.

[0009] When the vehicle descends a very long slope, the drive motor / generator needs to generate electricity for a long time for braking. If the generated power is close to fully charging the power battery, the central controller will control the power generation to send part or all of the power to the air-cooled power radiator. The generated electricity is dissipated by natural air cooling or forced air cooling by the motor fan, thereby protecting the power battery.

[0010] At low to medium speeds, the vehicle uses a power battery to power the drive motor / generator to propel it. The engine does not start and therefore does not drive the vehicle, avoiding the problem of low engine efficiency when power demand is low. At medium to high speeds, the fuel / gas engine starts to drive the vehicle. If there is still excess power after the engine has driven the vehicle, the central controller selects to generate electricity through the drive motor / generator and store it in the power battery. During acceleration or climbing, the drive motor / generator can assist the engine in driving the vehicle. During deceleration or going downhill, the drive motor / generator can switch to generator mode to recover kinetic energy and store it in the power battery. This significantly improves both the vehicle's power and fuel / gas economy.

[0011] Compared to existing fuel / gas engine vehicles, the advantages of this invention are: enhanced power, reduced fuel consumption, improved long-distance braking safety, and more convenient, safe, and energy-efficient use of air conditioning and other electrical appliances while parked. Because large and medium-sized passenger and freight vehicles have significant weight, considerable driving power is required for easy acceleration during start-up and high-speed uphill driving, while less power is needed for constant speed driving on flat roads. Therefore, adding a drive motor to assist drive effectively solves this problem. Similarly, due to the significant weight of large and medium-sized passenger and freight vehicles, their braking force, especially when descending long slopes, is very large. Relying solely on friction braking would cause the friction braking system to overheat, affecting safety, and a large amount of energy would be wasted through heat, which is also not energy-efficient. The hybrid power system of this invention can use the drive motor / generator for regenerative braking, especially when descending long slopes. Regenerative braking can significantly reduce the burden on the friction braking system, and a large amount of energy can be recovered through power generation and stored in the power battery. This energy can then be used to power the drive motor / generator to assist drive during subsequent uphill driving, thereby reducing fuel / gas consumption. When parked and resting, the power battery can be used to power the air conditioning system without starting the engine. When the power battery is low, the engine can be started to generate electricity while parked, which is energy-saving and safer. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the hybrid electric power system for large passenger and freight vehicles in this invention.

[0013] In the diagram: 1. Fuel / Gas engine; 2. Clutch; 3. Gear reducer; 4. Drive motor / generator; 5. Input shaft; 6. Intermediate shaft; 7. First-stage transmission synchronizer; 8. Driven gear; 9. Sun gear; 10. External gear ring; 11. Planetary gear; 12. Planetary gear carrier; 13. Synchronizer; 14. Second-stage transmission synchronizer; 15. Second-stage transmission gear pair; 16. Output shaft; 17. Power battery; 18. Main reducer gear pair; 19. Differential; 20. Drive wheel; 21. Front wheel; 22. Hybrid power transmission; 23. Air-cooled power radiator; 24. Central controller. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] This invention provides, for example Figure 1A hybrid electric vehicle system for medium and large passenger and freight vehicles includes a central controller 24, a fuel / gas engine 1, a clutch 2, a hybrid transmission 22, a power battery 17, and an air-cooled power radiator 23. The output end of the drive motor / generator 4 on the hybrid transmission 22 is connected to the input end of the gear reducer 3. The output end of the gear reducer 3 is connected to the input shaft 5. The fuel / gas engine 1 drives the input shaft 5 through the clutch 2. The input shaft 5 drives the intermediate shaft 6 through a first-stage three-speed transmission. The intermediate shaft 6 drives the output shaft 16 through a second-stage four-speed transmission. The first-stage three-speed transmission creates a total of 12 gears across three gear ranges, thereby driving the main reducer gear pair 18 and the differential 19 on the rear axle, and driving the drive wheels 20 to rotate the front wheels 21, thus driving the vehicle.

[0016] The hybrid transmission 22 also includes a sun gear 9, an external gear ring 10, planetary gears 11, and a planetary gear carrier 12. The lowest gear of the three-speed transmission in the hybrid transmission 22 is a planetary gear reducer. The sun gear 9 of the planetary gear reducer is coaxially fixed with the driven gear 8 of the intermediate gear. The external gear ring 10 is fixed to the housing of the hybrid transmission 22. The planetary gear carrier 12 is engaged with the intermediate shaft 6 through a synchronizer 13. After the driven gear 8 of the second gear has already been reduced in speed, the planetary gear reducer further reduces the speed to form the lowest gear.

[0017] When shifting gears, the clutch 2 of the hybrid transmission 22 disengages, the drive motor / generator 4 adjusts its speed, and the gear shift is performed via a shift synchronizer. In addition to disengaging the clutch 2, the hybrid transmission 22 adjusts the speed of the drive motor / generator 4 to bring the rotational speeds of the shift synchronizer and the corresponding gears close, allowing for smooth gear shifting through the engagement of the shift synchronizer.

[0018] The central controller 24 is electrically connected to the drive motor / generator 4, the power battery 17, the air-cooled power radiator 23, and the fuel / gas engine 1. The drive motor / generator 4 is driven by the central controller 24 based on factors such as the current vehicle driving conditions, the power battery 17, and the driver's power demand. It can drive the vehicle alone or in conjunction with the fuel / gas engine 1. It can also switch to generator to generate electricity to brake the vehicle when the fuel / gas engine 1 has surplus power or when the vehicle is decelerating or going downhill, and store the electricity in the power battery 17.

[0019] When the vehicle descends a very long slope, the drive motor / generator 4 needs to generate electricity for a long time for braking. If the generated power is close to fully charging the power battery 17, the central controller 24 controls the power generation to be partially or completely sent to the air-cooled power radiator 23. The generated electricity is dissipated by natural air cooling or forced air cooling by the motor fan, thereby protecting the power battery 17.

[0020] For heavy-duty large vehicles, due to the significant variations in load, a single-stage transmission requires three gears. Ordinary large vehicles may not require the lowest-speed planetary gear reduction gear. The sun gear 9 of the lowest-speed planetary gear reducer is coaxially fixed with the second-speed driven gear 8. The external gear ring 10 is fixed to the housing of the hybrid transmission 22. The planetary gear carrier 12 engages with the intermediate shaft 6 via synchronizer 13. Since the lowest gear reduces speed again via the planetary gear reducer after the second-speed driven gear 8 has already reduced speed, a large reduction ratio can be obtained. Furthermore, by selectively engaging the single-stage transmission shift synchronizer 7, the middle and higher gears of the single-stage transmission can be obtained.

[0021] There are four pairs of two-stage transmission shift gear pairs 15 between the intermediate shaft 6 and the output shaft 16, forming four gears of the two-stage transmission shift. Different gears are selected by two two-stage transmission shift synchronizers 14. Each shift is achieved by adjusting the speed of the drive motor / generator 4 so that the speed of the synchronizer 13 to be engaged is close to that of the corresponding gear. The shift can then be smoothly achieved by engaging the shift synchronizers.

[0022] The three gears of the first-level gearbox are combined in multiples to form a total of 12 gears. These 12 gears are divided into high, medium, and low gear segments, with four gears in each segment. For ordinary large vehicles, a combination of a first-level gear, a second-level gear, and a second-level gear (four gears in total) results in 8 gears. These 8 gears are also divided into high, low, and two gear segments, with four gears in each segment. There is no reverse gear; reversing is achieved by reversing the drive motor / generator 4. Gear shifting is automatically selected by the central controller 24 based on the vehicle's current operating conditions.

[0023] The power battery 17 is normally kept at a charge level of around 55%, with space reserved for both discharge and charge storage to meet the power requirements of the drive motor / generator 4 for auxiliary drive and the charging space required for braking and power generation when going up or down long slopes. When the power battery 17 has a normal capacity, the fuel / gas engine 1 does not start during start-up or low-speed driving, the clutch 2 disengages, and the vehicle is driven solely by the drive motor / generator 4. Due to the low-speed, high-torque characteristics of the electric motor, unless there is an extreme heavy load, hill start, or very low battery condition, the middle gear 5 of the hybrid transmission 22 is generally sufficient. If the acceleration requirement is not too high, the drive motor / generator 4 can drive the vehicle independently from the middle gear range of 5th to 8th gear. When the vehicle accelerates to medium to high speeds, and the gear reaches the higher gear range of 9th gear or above, the power demand is greater. At this time, the central controller 24 controls the clutch 2 to engage, starting the fuel / gas engine 1 to drive the vehicle. When a large amount of power is needed, the drive motor / generator 4 provides auxiliary drive. When the fuel / gas engine 1 has surplus power and the power battery 17 has a charge lower than the set value, the drive motor / generator 4 switches to generator mode to charge the power battery 17. The lower gears (1st to 4th) are rarely used, only for extreme conditions such as starting on a hill under heavy load or prolonged low-speed crawling that causes the battery charge (17) to be too low. For ordinary medium and large-sized vehicles with relatively low load capacities, the lowest gear range (1st to 4th) may not be necessary. Of course, the gears used and the starting gear of the fuel / gas engine are not fixed; the central controller (24) will determine the appropriate gear based on factors such as the vehicle's load, driving conditions, battery charge, and the driver's power requirements.

[0024] When the vehicle decelerates or goes downhill, the drive motor / generator 4 switches to generator braking and stores the generated electricity in the power battery 17. When the vehicle encounters an extreme long downhill condition, the braking power generated by the drive motor / generator 4 will bring the power battery 17 close to full charge. To avoid overcharging and damaging the power battery, the central controller 24 controls the power to send part or all of the generated electricity to the air-cooled power radiator 23. The generated electricity is dissipated by natural air cooling or forced air cooling by the motor fan, thereby protecting the power battery 17.

[0025] When the vehicle is parked and the power battery 17 is low on power, all the synchronizers of the hybrid transmission 22 are not engaged, the transmission is in neutral, the clutch 2 is engaged, and the fuel / gas engine 1 starts to drive the drive motor / generator 4 to generate electricity and charge the power battery 17. Since the power of the fuel / gas engine 1 and the drive motor / generator 4 is large enough, the charging speed and efficiency are very high, and the engine can charge the power battery 17 in a short time.

[0026] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A hybrid electric vehicle system for medium and large passenger and freight vehicles, comprising a central controller (24), a fuel / gas engine (1), a clutch (2), a hybrid transmission (22), a power battery (17), and an air-cooled power radiator (23), characterized in that: The output end of the drive motor / generator (4) on the hybrid transmission (22) is connected to the input end of the gear reducer (3), and the output end of the gear reducer (3) is connected to the input shaft (5). The fuel / gas engine (1) drives the input shaft (5) through the clutch (2). The input shaft (5) drives the intermediate shaft (6) through a first-level three-speed transmission. The intermediate shaft (6) drives the output shaft (16) through a second-level four-speed transmission, thereby driving the main reducer gear pair (18) and differential (19) on the rear axle, and driving the drive wheel (20) to drive the front wheel (21) to rotate, thus driving the vehicle to travel. The hybrid transmission (22) is also equipped with a sun gear (9), an external gear ring (10), planetary gears (11) and a planetary gear carrier (12). The lowest gear of the first-level three-speed transmission on the hybrid transmission (22) is a planetary gear reducer. The sun gear (9) of the planetary gear reducer is coaxially fixed with the driven gear (8) of the middle gear position. The external gear ring (10) is fixed on the housing of the hybrid transmission (22). The planetary gear carrier (12) is engaged with the intermediate shaft (6) through a synchronizer (13). By selecting and engaging the first-level transmission shift synchronizer (7), the middle and high gear positions of the first-level transmission can be obtained. On the basis that the driven gear (8) of the second gear has already decelerated, the planetary gear reducer decelerates again to form the lowest gear.

2. The hybrid electric vehicle system for medium and large passenger and freight vehicles according to claim 1, characterized in that: When the hybrid transmission (22) shifts gears, the clutch (2) disengages, and the speed of the drive motor / generator (4) is adjusted so that the rotational speed between the shift synchronizer to be engaged and the corresponding gear is close. Then, the shift synchronizer engages and shifts gears smoothly.

3. The hybrid electric vehicle system for medium and large passenger and freight vehicles according to claim 1, characterized in that: The central controller (24) is electrically connected to the drive motor / generator (4), the power battery (17), the air-cooled power radiator (23), and the fuel / gas engine (1).

4. A hybrid electric vehicle system for medium and large passenger and freight vehicles according to claim 1, characterized in that: When the vehicle descends a very long slope, the drive motor / generator (4) needs to generate electricity for a long time to brake. The generated electricity is close to fully charging the power battery (17). The central controller (24) controls the power generation to be partially or completely directed to the air-cooled power radiator (23). The generated electricity is dissipated by natural air cooling or forced air cooling by the motor fan, thereby protecting the power battery (17).

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