CN105805284B

CN105805284B - Gearbox lubricating system and method suitable for hybrid electric vehicle

Info

Publication number: CN105805284B
Application number: CN201410855513.0A
Authority: CN
Inventors: 阮鸥; 陈昊; 王品; 李玲玲; 黄鹏
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2014-12-31
Filing date: 2014-12-31
Publication date: 2019-12-10
Anticipated expiration: 2034-12-31
Also published as: CN105805284A

Abstract

The invention discloses a gearbox lubricating system suitable for a hybrid electric vehicle. The lubricating oil is accommodated in the gearbox. The electric pump is communicated with the bottom and the top of the gearbox. The controller is connected with the electric pump and used for controlling the electric pump to suck lubricating oil out of the bottom of the gearbox, pressurize the lubricating oil and spray the lubricating oil from the top of the gearbox to lubricate the gearbox. The mechanical pump is communicated with the bottom and the top of the gearbox. The mechanical pump is connected with an engine of an automobile and used for sucking lubricating oil out of the bottom of the gearbox along with the starting of the engine, spraying the lubricating oil from the top of the gearbox after pressurization so as to lubricate the gearbox. Therefore, even if the driving force transmission path of the driving motor and the power transmission path of the engine work in a low-speed large-torque and high-speed area, the lubrication requirement of the gearbox lubrication system can be met. The invention also discloses a gearbox lubricating method suitable for the hybrid electric vehicle.

Description

Gearbox lubricating system and method suitable for hybrid electric vehicle

Technical Field

The invention relates to the automobile technology, in particular to a gearbox lubricating system and method suitable for a hybrid electric vehicle.

background

An existing gearbox lubrication system adopts an electric pump to establish oil pressure, and controls a motor of the electric pump to execute a set lubrication strategy through a motor controller, namely, the rotating speed of the motor is controlled according to a current gear and a vehicle speed signal so as to adjust the oil injection quantity of an oil pump of the electric pump. Compared with the traditional splash lubrication which provides lubrication power by means of the centrifugal force of gear rotation and the oil spraying lubrication by means of a mechanical pump directly connected to a gear shaft, the system solves the problem that the lubrication of the gearbox is poor under the working condition of low speed and high torque, and the defect that the lubrication is excessive when the gearbox runs at high speed is overcome by the aid of the characteristic that the rotation speed of the motor is adjusted independently of the rotation speed of the gearbox.

on the other hand, with the deterioration of global environment, environmental protection automobiles are more and more emphasized, and particularly hybrid automobiles are widely used at present. The power system of the hybrid electric vehicle is complex, particularly the heavy hybrid electric vehicle adopts a high-power driving motor, and a driving force transmission path of the driving motor and a power transmission path of an engine can work in a low-speed large-torque and high-speed area, so that the oil injection point and the oil injection quantity of a gearbox lubricating system are greatly increased. Therefore, if the lubrication system employs an electric pump, higher demands are made on the power of the electric pump. However, the direct current voltage for supplying power to the motor is set (12V), the size and the weight of the electric oil pump assembly are determined by the limited space of the gearbox and the surrounding space of the gearbox and the requirement of weight reduction of the whole vehicle, and the current of the motor is increased when the power of the motor is increased. In addition, because the viscosity of the lubricating oil changes along with the temperature change, the lower the temperature of the lubricating oil is, the higher the required power of the motor is under the same rotating speed of the motor, particularly under severe cold weather, the starting load of the motor is large, and the situation that the starting is difficult and even the rotation is blocked can occur. If the motor works at a high rotating speed for a long time, the temperature rise of the motor can reduce the performance of the motor, particularly the permanent magnet causes serious demagnetization, and the loading capacity of the motor is poorer and poorer. Which will ultimately affect the working life of the lubrication system and the lubrication effect of the gearbox.

With the increasing importance of automobile fuel economy indexes, the automobile gearbox has the tendency of multiple gears and is shifted more frequently. The double-clutch automatic transmission automobile needs a hydraulic system to provide power for gear shifting and clutch separation and combination, the mechanism acts more frequently, particularly, a heavy hybrid power automobile strives to have strong power output, and transmission oil with too low viscosity cannot be selected to ensure the lubricating effect under large torque.

in conclusion, in order to ensure heavy tasks of clutch, gear shifting, lubrication and cooling and high viscosity of lubricating oil at low temperature, a high-capacity electric oil pump and a motor must be additionally arranged to ensure the loading capacity of the motor. Moreover, such a lubrication system lacks necessary monitoring of the system flow and oil temperature, lacks feedback amount of system control, and is not favorable for ensuring the reliability of the lubrication system. That is, the existing lubricating system has the defects of large volume, heavy weight, insufficient reliability and incapability of realizing energy-saving accurate control.

Disclosure of Invention

the present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention needs to provide a gearbox lubricating system and a gearbox lubricating method suitable for a hybrid electric vehicle.

The invention discloses a gearbox lubricating system suitable for a hybrid electric vehicle. The lubricating oil is contained in the gearbox. The electric pump is communicated with the bottom and the top of the gearbox. The controller is connected with the electric pump and used for controlling the electric pump to suck the lubricating oil out of the bottom of the gearbox according to a lubricating strategy, pressurize the lubricating oil and spray the lubricating oil from the top of the gearbox to lubricate the gearbox. The mechanical pump is communicated with the bottom and the top of the gearbox. The mechanical pump is connected with an engine of the automobile and used for spraying the lubricating oil from the top of the gearbox after the lubricating oil is sucked out from the bottom of the gearbox and pressurized along with the starting of the engine so as to lubricate the gearbox.

Under the condition that the automobile is driven by the driving motor and the engine at the same time, even if the driving force transmission path of the driving motor and the power transmission path of the engine work in a low-speed large-torque and high-speed area, the lubrication system of the gearbox can meet the lubrication requirement.

In some embodiments, the hybrid vehicle includes an electric-only mode and a hybrid mode, and the controller controls the electric pump to lubricate the transmission in the electric-only mode and selectively lubricate the transmission in the hybrid mode.

In some embodiments, the controller is configured to control the electric pump to start when the engine speed is lower than a first preset speed in the hybrid mode.

In some embodiments, the controller is configured to control the electric pump to not start when the engine speed is higher than a second preset speed in the hybrid mode.

In some embodiments, a first interface and a second interface are formed at the bottom of the transmission, an oil return interface is formed at the top of the transmission, the lubrication system further includes a first oil outlet pipe, a second oil outlet pipe and an oil return pipe, the first oil outlet pipe is connected to the first interface and the oil return pipe, the second oil outlet pipe is connected to the second interface and the oil return pipe, the oil return pipe is connected to the oil return interface, the electric pump is disposed on the first oil outlet pipe, and the mechanical pump is disposed on the second oil outlet pipe.

In some embodiments, the oil pump further comprises a check valve, the check valve is connected to the first oil outlet pipe, the second oil outlet pipe and the oil return pipe, and the check valve is used for preventing the lubricating oil in the first oil outlet pipe from entering the second oil outlet pipe when the mechanical pump is not started and preventing the lubricating oil in the second oil outlet pipe from entering the first oil outlet pipe when the electric pump is not started.

in some embodiments, the transmission lubrication system further comprises an oil cooler disposed on the oil return pipe for cooling the lubricating oil.

In some embodiments, the oil cooler is connected to an oil cooler of the engine such that the oil cooler heats the lubricating oil using a high temperature of cooling water of the oil cooler.

In some embodiments, the transmission lubrication system further comprises a filter disposed on the oil return pipe for filtering the lubricating oil.

In some embodiments, the transmission lubrication system further comprises an oil pressure sensor disposed on the oil return pipe for measuring oil pressure within the oil return pipe; the oil pressure sensor is connected with the controller and used for feeding back the oil pressure to the controller.

In some embodiments, the electric pump has a pressure relief valve built therein, and the pressure relief valve may set a pressure relief point for opening the pressure relief when the pressure in the electric pump reaches the pressure relief point.

In some embodiments, the temperature sensor is disposed at the bottom of the transmission for sensing the oil temperature of the lubricating oil, and the temperature sensor is connected to the transmission controller for feeding back the oil temperature, so that the transmission controller can control and determine the start and operation of the electric pump.

The invention discloses a gearbox lubricating method applicable to a hybrid electric vehicle, which comprises a gearbox, lubricating oil, an electric pump and a mechanical pump, wherein the lubricating oil is contained in the gearbox, and the electric pump and the mechanical pump are respectively communicated with the bottom and the top of the gearbox and are used for sucking out the lubricating oil from the bottom of the gearbox, pressurizing the lubricating oil and then spraying the lubricating oil from the top of the gearbox to lubricate the gearbox; the method comprises the following steps:

Judging the current working mode of the automobile, wherein the working mode comprises a pure electric mode driven by a driving motor and a hybrid power mode simultaneously driven by the driving motor and an engine; and

When the vehicle is in the electric-only mode, the electric pump lubricates the transmission; when the vehicle is in the hybrid mode, the mechanical pump activates lubrication of the transmission as the engine is started, and the electric pump selectively activates or deactivates depending on the speed of the engine.

In some embodiments, the controller controls the electric pump to lubricate a transmission in the hybrid mode when the engine speed is below a first preset speed;

The controller controls the electric pump not to lubricate the gearbox when the engine speed is higher than a second preset speed in the hybrid power mode, wherein the second preset speed is higher than the first preset speed.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic diagram of a transmission lubrication system in accordance with a preferred embodiment of the present invention.

FIG. 2 is a schematic diagram of a transmission lubrication system according to another preferred embodiment of the present invention.

FIG. 3 is a schematic illustration of a method of lubricating a transmission according to a preferred embodiment of the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "first", "second" and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted", "connected" and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The following disclosure provides many different embodiments or examples for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize applications of other processes and/or uses of other materials.

Referring to FIG. 1, a transmission lubrication system 10 in accordance with a preferred embodiment of the present invention is adapted for use in a hybrid vehicle. The hybrid vehicle may be driven by a drive motor (EV mode) or by both the drive motor and the engine (HEV mode). The gearbox lubrication system 10 comprises a gearbox 11, lubricating oil 12, an electric pump 13, a controller 14 and a mechanical pump 15. The lubricant oil 12 is contained in the transmission case 11. The electric pump 13 is communicated with the bottom and the top of the gearbox 11. The controller 14 is connected to the electric pump 13 for controlling the electric pump 13 to suck the lubricant 12 out of the bottom of the transmission case 11, pressurize the lubricant and spray the lubricant out of the top of the transmission case 11 to lubricate the transmission case 11. The mechanical pump 15 communicates between the bottom and the top of the transmission case 11. The mechanical pump 15 is connected to the engine of the vehicle for spraying the lubricant 12 from the top of the gearbox 11 after being pressurized and sucked out from the bottom of the gearbox 11 with the engine start for lubricating the gearbox 11.

In the EV mode, the hybrid vehicle generally runs at a low speed, the lubrication requirement of the transmission 11 is low, and the lubrication requirement of the hybrid vehicle in the EV mode can be met by operating the electric pump 13. In the HEV mode, the hybrid vehicle generally runs at a higher vehicle speed, the lubrication requirement of the transmission 11 is higher at this time, that is, a larger lubrication amount is required, the mechanical pump 15 mainly works at this time to meet the lubrication requirement, the electric pump 13 may or may not participate in the operation, and the advantage of large displacement and large power of the mechanical pump 15 relative to the electric pump 13 is fully utilized.

In the transmission lubrication system 10 according to the preferred embodiment of the present invention, in the HEV mode of the hybrid electric vehicle, if the hybrid electric vehicle operates under the low-speed high-torque condition, the engine speed is low, and the lubrication requirement of the transmission under the condition cannot be met by using the mechanical pump 15 alone for lubrication, so the electric pump 13 and the mechanical pump 15 need to be started at the same time. Thus, the lubrication requirements can be met with increased injection points and injection quantities for the transmission lubrication system 10. When the engine speed is higher, the mechanical pump 15 is used alone for lubrication at the moment, so that the lubrication requirement of the gearbox under the working condition can be met, and the speed of the electric pump 13 can be reduced or the electric pump 13 can be turned off. Thus, the controller 14 controls the electric pump 13 to be activated in the EV mode, and controls the electric pump 13 to be selectively activated in the HEV mode.

The flow rate of the electric pump 13 is easily adjustable, and the mechanical pump 15 works with the engine and is not easily adjustable. The electric pump 13 can supplement the mechanical pump 15 to precisely adjust the amount of lubrication.

As another example, in the HEV mode, the transmission lubrication system 10 is only engaged in transmission 11 lubrication by the mechanical pump 15, and the electric pump 13 is not engaged in transmission 11 lubrication. The advantages are that: the mutual interference of two paths of lubricating oil flows when the mechanical pump 15 and the electric pump 13 work simultaneously is avoided, the frequent start and stop of the electric pump 13 are also avoided, and the system reliability is enhanced.

Specifically, the electric pump 13 includes an oil pump 131 and a motor 132. The controller 14 is coupled to the motor 132 to control the speed of the motor 132 to implement the lubrication strategy.

The bottom of the transmission case 11 is formed with a first interface 111 and a second interface 112, the top of the transmission case 11 is formed with an oil return interface 113, the lubrication system 10 further includes a first oil outlet pipe 16, a second oil outlet pipe 17, an oil return pipe 18 and a check valve 19, the first oil outlet pipe 16 is connected with the first interface 111 and the check valve 19, the second oil outlet pipe 17 is connected with the second interface 112 and the check valve 19, the oil return pipe 18 is connected with the oil return interface 113 and the check valve 19, the electric pump 13 is disposed on the first oil outlet pipe 16, the mechanical pump 15 is disposed on the second oil outlet pipe 17, and the check valve 19 is used for preventing the lubricating oil 12 of the first oil outlet pipe 16 from entering the second oil outlet pipe 17 when the mechanical pump 15 is not started and preventing the lubricating oil of the second oil outlet pipe 17 from entering the first oil outlet pipe 16 when the electric pump 13 is not.

That is, the check valve 19 can prevent the oil 12 from returning from the first oil outlet pipe 16 to the second oil outlet pipe 17 after the oil 12 is sucked by the electric pump 13 due to the absence of oil pressure from the mechanical pump 15 when the vehicle is operating in the EV mode, and the check valve 19 can prevent the oil 12 from returning from the second oil outlet pipe 17 to the first oil outlet pipe 16 after the oil 12 is sucked by the mechanical pump 15 due to the absence of oil pressure from the electric pump 13 when the vehicle is operating in the HEV mode.

The gearbox lubrication system 10 further comprises an oil cooler 1a, which oil cooler 1a is arranged on the oil return pipe 18 for reducing the temperature of the lubricating oil 12.

The oil cooler 13 may also be connected to an oil cooler of the engine. In this way, the oil cooler 13 can heat the lubricating oil by using the high temperature of the cooling water of the oil cooler. Therefore, the oil cooler 13 has both high-temperature cooling and low-temperature heating functions. When the oil temperature is lower than engine oil cooling water of the engine, the oil cooler 13 heats the lubricating oil 12 to reduce the load of the electric pump 13, improve the lubricating effect and improve the transmission efficiency. When the oil temperature is higher than the engine oil cooling water of the engine, the oil cooler 13 cools the lubricating oil 12, so that the oil temperature is kept in a proper range, the phenomenon that the temperature rise of the speed change gear is too high due to too low viscosity of the lubricating oil 12 is avoided, and the service life of the gear is prolonged.

in actual use, the mutual friction of the speed changing gears in the gearbox 11 will raise the temperature of the lubricating oil 12, and the viscosity of the lubricating oil 12 will be too low due to too high oil temperature, thus affecting the lubricating effect.

The gearbox lubrication system 10 further comprises a filter 1b arranged on the oil return pipe 18 for filtering the lubricating oil 12.

The transmission gear is prone to generate metal debris during the run-in phase, and therefore, filtering the lubricating oil 12 plays an important role in improving the life of the transmission gear.

The gearbox lubrication system 10 further comprises an oil pressure sensor 1c, and the oil pressure sensor 1c is arranged on the oil return pipe 18 and used for measuring the oil pressure in the oil return pipe 18. The oil pressure sensor 1c is connected to the controller 14 for feeding back the oil pressure.

Thus, the oil pressure can be prevented from being too low or too high. The oil pressure can reflect the amount of the injected lubricating oil on one hand, namely the injection amount. The oil pressure is also fed back to the electric pump 13, and the flow rate of the electric pump 13 is adjusted.

Specifically, the gearbox lubrication system 10 further includes a three-way pipe 1d disposed on the oil return pipe 18, and the oil pressure sensor 1c is disposed at one of outlets of the three-way pipe 1 d.

The mechanical pump 15 further includes an oil outlet path 151, and the oil outlet path 151 is connected to a shift mechanism or a clutch hydraulic system of the vehicle, and is configured to provide power to the shift mechanism or the clutch hydraulic system.

Therefore, the power can be provided, and the oil pressure of the lubricating circuit can be prevented from being too high when the engine runs at a high speed.

In addition, the transmission lubrication system 10 further includes a spray header 1e, and the spray header 1e is disposed in the transmission 11, and is located at the top and connected to the oil return port 113 to spray the lubricating oil 12.

Referring to FIG. 2, another preferred embodiment of a transmission lubrication system 10a of the present invention is substantially identical to transmission lubrication system 10.

However, in the present embodiment, the electric pump 13 is provided with a relief valve (not shown) therein, and the relief valve may be provided with a relief point for opening the relief when the pressure in the electric pump 13 reaches the relief point.

This also prevents the oil pressure of the electric pump 13 from becoming too high.

In combination with the pressure relief of the oil outlet passage, the transmission lubrication system 10 can omit an additional pressure relief device or a pressure monitoring device (i.e., the oil pressure sensor 1c can be omitted, so as to achieve the over-pressure protection of the system at the minimum cost and improve the reliability of the system).

The controller 14 is connected with a transmission controller 20 of the automobile, the transmission controller 20 is used for inputting a control signal to the controller, and the controller 14 executes a lubrication strategy according to the control signal.

the gearbox lubrication system 10a comprises a temperature sensor 1f, the temperature sensor 1f is arranged at the bottom of the gearbox 11 and used for sensing the oil temperature of the lubricating oil 12, and the temperature sensor 1f is connected with the transmission controller 20 and used for feeding back the oil temperature.

In addition, the oil cooler 1a is connected to an oil cooler of the engine.

thus, the oil cooler 13 has both high-temperature cooling and low-temperature heating functions. When the oil temperature is lower than engine oil cooling water of the engine, the oil cooler 13 heats the lubricating oil 12 to reduce the load of the electric pump 13, improve the lubricating effect and improve the transmission efficiency. When the oil temperature is higher than the engine oil cooling water of the engine, the oil cooler 13 cools the lubricating oil 12, so that the oil temperature is kept in a proper range, the phenomenon that the temperature rise of the speed change gear is too high due to too low viscosity of the lubricating oil 12 is avoided, and the service life of the gear is prolonged.

For lubricating and cooling the speed changing gear, the lubricating oil should be in a certain temperature range. Too high a temperature, i.e. too low a viscosity of the lubricating oil, results in poor lubricating effect and accelerated aging of the lubricating oil; too low temperature means too high viscosity of the lubricating oil, reducing transmission efficiency, and poor fluidity of the lubricating oil, incomplete coverage of the lubricating oil.

For the electric pump 13 for lubrication, a high lubricating oil temperature means that the load on the electric pump 13 is small, and the power consumed by the electric pump 13 for injecting a certain amount of lubricating oil is small; on the other hand, the low-level lubricating oil is opposite, namely, the load is large, the power consumption is large, and the starting of the electric motor main body is difficult. Therefore, when the temperature of the lubricating oil is high, the electric pump 13 is started or operated by adopting a lower duty ratio; otherwise, a higher duty cycle is required for starting or running.

The gearbox lubricating method for the hybrid electric vehicle in the preferred embodiment of the invention comprises the following steps:

The electric pump 13 and the mechanical pump 15 are selectively activated or deactivated to lubricate the gearbox 11, depending on the current operating mode of the vehicle.

when the vehicle is in a pure electric mode, the electric pump 13 lubricates the gearbox 11; when the vehicle is in hybrid mode, the mechanical pump 15 is connected to the engine shaft and lubricates the gearbox 11 as the engine is started, and the electric pump 13 is selectively started or stopped to lubricate the gearbox 11.

When the vehicle is in hybrid mode, the mechanical pump 15 is connected to the engine shaft and is turned off as the engine starts for lubrication of the gearbox 11 and is turned off as the engine is turned off and the electric pump 13 is turned off.

When the vehicle is in hybrid mode, the mechanical pump 15 is connected to the engine shaft and is turned off as the engine starts for lubrication of the gearbox 11 and is turned off as the engine is turned off, and the electric pump 13 is selectively turned on or off depending on the speed of the engine.

When the engine speed is lower than a first preset speed n1, the electric pump 13 is started to lubricate the gearbox 11; when the engine speed is higher than the second preset speed n2, the electric pump 13 is turned off to stop lubricating the gearbox 11, and the second preset speed n2 is higher than the first preset speed n 1.

It is understood that the first preset rotation speed n1 and the second preset rotation speed n2 are set to prevent the motor 132 from being frequently started.

When the engine speed is between the first preset speed n1 and the second preset speed n2, the engine speed is inversely related to the motor speed of the electric pump 13.

When the automobile is in a pure electric mode, the electric pump 13 is started firstly, and then the automobile continuously runs, starts or closes according to the gear and the speed of the automobile under the condition that the electric pump 13 is started; when the automobile is in a hybrid power mode, the electric pump 13 is continuously operated, started or closed according to the gear and the speed of the automobile and the rotating speed of the engine under the condition that the electric pump 13 is started.

the electric pump 13 is started by determining whether or not to start based on the bus voltage of the electric pump 13 and the temperature of the power device.

After the electric pump 13 is started, whether the speed is reduced or shut down is judged according to the three-phase winding integrated current, the direct-current bus voltage, the temperature of the power device and the oil pressure of the electric pump 13.

In the description of the present specification, reference to the description of the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples", etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

while embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A transmission lubrication system adapted for use in a hybrid vehicle, comprising:

A gearbox;

Lubricating oil accommodated in the gearbox;

The electric pump is communicated with the bottom and the top of the gearbox;

The controller is connected with the electric pump and is used for controlling the electric pump to suck the lubricating oil out of the bottom of the gearbox, pressurize the lubricating oil and spray the lubricating oil from the top of the gearbox to lubricate the gearbox; and

The mechanical pump is communicated with the bottom and the top of the gearbox; the mechanical pump is connected with an engine of the automobile and used for spraying the lubricating oil from the top of the gearbox after the lubricating oil is sucked out from the bottom of the gearbox and pressurized along with the starting of the engine so as to lubricate the gearbox;

The bottom of gearbox is formed with first interface and second interface, the top of gearbox is formed with the oil return interface, lubricating system still includes first play oil pipe, second play oil pipe and returns the oil pipe, first play oil union coupling first interface reaches return the oil pipe, the second goes out oil union coupling the second interface reaches return the oil pipe, it connects to return the oil pipe the oil interface, the electric pump sets up on the first play oil pipe, the mechanical pump sets up on the second goes out oil pipe.

2. The transmission lubrication system of claim 1, wherein the hybrid vehicle includes an electric-only mode and a hybrid mode, and the controller controls the electric pump to lubricate the transmission in the electric-only mode and selectively lubricate the transmission in the hybrid mode.

3. The transmission lubrication system of claim 2, wherein the controller is configured to control the electric pump to lubricate the transmission in the hybrid mode when the engine speed is less than a first predetermined speed.

4. The transmission lubrication system of claim 2, wherein the controller is configured to control the electric pump to not lubricate the transmission in the hybrid mode when the engine speed is greater than a second predetermined speed.

5. The transmission lubrication system according to claim 1 further comprising a check valve connecting said first outlet line, said second outlet line and said return line, said check valve preventing said lubricant in said first outlet line from entering said second outlet line when said mechanical pump is not activated and preventing said lubricant in said second outlet line from entering said first outlet line when said electric pump is not activated.

6. The transmission lubrication system of claim 1 further comprising an oil cooler disposed on said oil return pipe for cooling said lubricating oil.

7. The transmission lubrication system of claim 6 wherein the oil cooler is coupled to an oil cooler of the engine such that the oil cooler utilizes the high temperature of the cooling water of the oil cooler to heat the lubricating oil.

8. the transmission lubrication system of claim 1 further comprising a filter disposed on said oil return line for filtering said lubricating oil.

9. The transmission lubrication system of claim 1 further comprising an oil pressure sensor disposed on said oil return tube for measuring oil pressure within said oil return tube; the oil pressure sensor is connected with the controller and used for feeding back the oil pressure to the controller.

10. a gearbox lubrication system as claimed in any one of claims 1 to 9 in which the electric pump incorporates a pressure relief valve which can set a pressure relief point, the pressure relief valve being arranged to open the pressure relief when the pressure in the electric pump reaches said pressure relief point.

11. The gearbox lubrication system according to any one of claims 1-9, comprising a temperature sensor disposed at the bottom of the gearbox for sensing the oil temperature of the lubricating oil, wherein the temperature sensor is connected to a transmission controller of the vehicle for feeding back the oil temperature for the transmission controller to control and determine the start and operation of the electric pump.

12. The lubrication method for the gearbox of the hybrid electric vehicle is characterized in that the vehicle comprises a gearbox, lubricating oil, an electric pump and a mechanical pump, wherein the lubricating oil is contained in the gearbox, and the electric pump and the mechanical pump are respectively communicated with the bottom and the top of the gearbox and are used for sucking out the lubricating oil from the bottom of the gearbox, pressurizing the lubricating oil and spraying the lubricating oil from the top of the gearbox to lubricate the gearbox; the bottom of gearbox is formed with first interface and second interface, the top of gearbox is formed with the oil return interface, the car still includes first oil pipe, second oil pipe and returns the oil pipe, first oil pipe connection first interface reaches return the oil pipe, the second oil pipe connection the second interface reaches return the oil pipe, it connects to return the oil pipe the oil interface, the electric pump sets up on first oil pipe, the mechanical pump sets up on the second oil pipe, the method includes the following steps:

13. a method of lubricating a transmission as set forth in claim 12, wherein the vehicle includes a controller that controls the electric pump to lubricate the transmission in the hybrid mode when the engine speed is below a first predetermined speed;