Disclosure of Invention
Aiming at the technical problems, the invention provides a digital gear shifting buffer system and a control method of a high-speed switch valve matrix, which utilize a digital hydraulic control technology to establish a hydraulic bridge circuit for a high-speed switch valve to form a digital hydraulic valve matrix and have more control autonomy and flexibility.
The technical scheme of the invention is as follows: the hydraulic power unit, the controller and the digital clutch hydraulic cylinder group are included; the digital clutch hydraulic cylinder group comprises clutches C1, C2, C3, CL, CH and CR and a locking clutch CB;
the hydraulic power unit comprises a first pressure circuit P s1 And a second pressure circuit P s2 ;
The digital clutch hydraulic cylinder group divides the clutches C1, C2, C3, CL, CH, CR and the locking clutch CB into three groups, namely a clutch group hydraulic cylinder C1, C2 and C3 with the number of gears, a functional clutch group hydraulic cylinder CL, CH, CR and a locking clutch group hydraulic cylinder CB;
the hydraulic cylinders C1, C2 and C3 of the clutch group with the number of gears are respectively connected with first to third three-position five-way reversing valves (61, 62 and 63) in front, the hydraulic cylinders CL, CH and CR of the functional clutch group are respectively connected with fourth to sixth three-position five-way reversing valves (64, 65 and 66) in front, and the hydraulic cylinder CB of the locking clutch group is connected with a two-position three-way reversing valve (67) in front;
the first pressure circuit P s1 The hydraulic half-bridges HSV1 and HSV2 are respectively connected with a port P1 and a port P2 of each reversing valve in the first three-position five-way reversing valves (61, 62 and 63); form a first and a second pressure output circuit (P) 1 、P 2 );
The second pressure circuit P s2 The port P1 and the port P2 of each reversing valve in the fourth-sixth three-position five-way reversing valves (64, 65 and 66) are respectively connected through A-type hydraulic half-bridges HSV3 and HSV4; form a third and a fourth pressure output circuit (P) 3 、P 4 );
The second pressure circuit P s2 Is also connected with the hydraulic half-bridge HSV5 through A typeA P port of the two-position three-way reversing valve (67); form a fifth pressure output circuit (P) 5 )。
The hydraulic control system further comprises a redundant oil circuit, wherein the redundant oil circuit comprises a redundant A-type hydraulic half-bridge HSV6, and the redundant A-type hydraulic half-bridge HSV6 is connected with the first pressure loop P in front s1 Then, connecting first to fifth hydraulic shuttle valves (51 to 55), wherein the first to fifth hydraulic shuttle valves (51 to 55) are correspondingly connected with the type-A hydraulic half bridges HSV1, HSV2, HSV3, HSV4 and HSV5 one by one; form a sixth pressure output circuit (P) 6 )。
The emergency oil circuit comprises a second two-position three-way emergency valve (92), a first two-position three-way emergency valve (91) and a manual reversing valve (93);
the first pressure circuit P s1 A port P connected with the first two-position three-way emergency valve (91), and the second pressure loop (P) s2 ) Is connected with a port P of the second two-position three-way emergency valve (92),
the A ports of the first two-position three-way emergency valve (91) and the second two-position three-way emergency valve (92) are respectively connected with the P1 port and the P2 port of the manual reversing valve (93); the outlets of the manual reversing valves (93) respectively pass through:
the first emergency shuttle valve (56) is connected with a gear number clutch group hydraulic cylinder C1;
the second emergency shuttle valve (57) is connected with a functional clutch group hydraulic cylinder CL;
the third emergency shuttle valve (58) is connected with a hydraulic cylinder CR of the functional clutch group;
the left position and the right position of the manual reversing valve (93) respectively correspond to a forward (D) gear and a reverse (R) gear, and correspond to a neutral gear (N) gear in the middle position.
Each hydraulic half bridge comprises a pair of two-position two-way normally-closed high-speed switch valves which are connected in series and have the same type, each high-speed switch valve is connected with a controller, and the controller controls the on-off of each high-speed switch valve through a PWM control signal; the high-speed switch valves are arranged in an array form to form a high-speed switch valve matrix.
And the controller is in pressure closed-loop control, and after comparing the target buffer pressure value with the actual working pressure value of the clutch hydraulic cylinder, the controller independently updates the initial opening time of two high-speed switching valves in the corresponding hydraulic half-bridge and the duty ratio of the PWM control signal, so that the net flow flowing into and out of the clutch hydraulic cylinder stably changes according to a preset rule.
The hydraulic power unit includes an engine (100), an oil tank (130), a temperature sensor (120), and first and second oil supply paths,
the first oil supply oil way sequentially comprises a first filter (102), a first hydraulic pump (103), a first electromagnetic overflow valve (101), a first filter (104) with a one-way valve, a first pressure gauge (105) and a first one-way valve (81);
the second oil supply path sequentially comprises a second filter (112), a second hydraulic pump (113), a second electromagnetic overflow valve (111), a second filter (114) with a one-way valve, a second pressure gauge (115) and a second one-way valve (82);
the engine (100) simultaneously drives the first hydraulic pump (103) and the second hydraulic pump (113);
the temperature sensor (120) is connected with the controller.
The first hydraulic pump (103) and the second hydraulic pump (113) are respectively connected with the first electromagnetic overflow valve (101) and the second electromagnetic overflow valve (111) in parallel, and the controller determines the power-on and power-off states of the first electromagnetic overflow valve (101) and the second electromagnetic overflow valve (111) according to the operation condition of a hydraulic cylinder of a vehicle shift clutch.
Pressure sensors are respectively arranged at the front ends of the clutches C1, C2, C3, CL, CH and CR and the locking clutch CB of the digital clutch hydraulic cylinder group; the pressure sensor is connected with the controller.
The controller calculates the actual working pressure value of each clutch hydraulic cylinder according to the relation between the detection pressure value of the factory-calibrated pressure output loop and the actual pressure value of the oil liquid of the clutch hydraulic cylinder and the data acquired by the pressure sensor;
the controller also stores buffer characteristic parameters at least comprising data such as oil temperature, buffer time, a clutch target buffer pressure value and the like, and inquires interpolation to obtain a target buffer pressure value according to the detected temperature value and the current buffer time.
The invention discloses a control method of a high-speed switch valve matrix digital gear shifting buffer system, which comprises the following steps:
before gear shifting, the clutches to be separated are all in a locking state, and the three-position five-way reversing valve corresponding to the clutches is in a working position and is always kept in the working position;
after a gear shifting instruction is received, oil in a hydraulic cylinder of the clutch to be separated flows out through an output hydraulic resistance high-speed switch valve of a certain hydraulic half bridge in the clutch group; in the preparation stage, a PWM control signal with the duty ratio of 20% is given, so that the to-be-separated clutch is slowly decompressed, and the pressure reserve coefficient in the clutch is eliminated; in the torque stage, the clutch to be separated adopts open-loop control, so that the duty ratio of a PWM control signal is reduced according to a certain slope, when the torque stage is finished, the clutch to be separated is completely separated, and a three-position five-way reversing valve corresponding to the clutch to be separated is switched to a middle position;
when a gear-shifting instruction is sent, a three-position five-way reversing valve corresponding to a clutch to be engaged is switched to another working position and is kept at the position all the time, oil flows into a hydraulic cylinder of the clutch to be engaged from another hydraulic half bridge in the clutch group, in a preparation stage, a PWM control signal with the duty ratio of 100 percent is input to a hydraulic resistance high-speed switching valve, a PWM control signal with the duty ratio of 0 percent is output to the hydraulic resistance high-speed switching valve, the clutch to be engaged is rapidly filled with oil to eliminate gaps between friction plates of the clutch, in a torque stage, the clutch to be engaged starts to slip and transmit torque, a controller adjusts an initial control value and an increase rate of the duty ratio of the PWM control signal input to the hydraulic resistance high-speed switching valve in a closed loop mode according to a preset torque transfer rule, the method comprises the steps that the boosting rate of a clutch to be combined and the pressure relief rate of a clutch to be separated are synchronized, smooth alternate lapping of torque is achieved, in the inertia stage, the duty ratio of an input hydraulic resistance high-speed switch valve is automatically adjusted through pressure closed loop control, the boosting rate of the clutch to be combined is controlled, meanwhile, the opening time of the output hydraulic resistance high-speed switch valve and the duty ratio of a PWM control signal are automatically adjusted, so that pressure fluctuation in the clutch to be combined is reduced, the pressure change rate in the clutch is enabled to stably change according to a preset buffering rule, after a clutch friction plate to be combined rotates synchronously, the PWM control signal with the duty ratio of the input hydraulic resistance high-speed switch valve being 100% is given, the PWM control signal with the duty ratio of the output hydraulic resistance high-speed switch valve being 0% is given, a hydraulic cylinder of the clutch is rapidly boosted to system pressure, and certain pressure is reserved in the clutch;
in the process, if the clutch is always in the joint state, the corresponding three-position five-way reversing valve is always in the working position, after the joint pressure of the clutch reaches a set value, the electromagnetic overflow valve is instructed to be electrified so as to unload the hydraulic pump, the energy consumption is saved, the temperature of the oil liquid is reduced, and when the pressure of the oil liquid of the clutch is reduced to be below a threshold value which ensures the reliable joint of the clutch, the electromagnetic overflow valve is deenergized so as to supplement the reduction of the pressure of the oil liquid in the clutch.
Compared with the prior art, the invention has the following beneficial effects:
1. according to the invention, the hydraulic half bridge consisting of two high-speed switching valves is adopted, the opening and closing states of the high-speed switching valves are changed by adjusting the duty ratio of a PWM control signal, and the pressure of a single clutch hydraulic cylinder is controlled, so that the pressure is changed according to an expected target, the control is more flexible and autonomous, and the gear shifting stability and riding comfort are improved; the pressure of a single pressure output loop is used as a feedback quantity, so that the closed-loop intelligent control of the pressure of the clutch hydraulic cylinder is realized, and the system can actively adapt to the conditions of oil temperature, external load change, engine speed change and the like;
2. in the gear shifting process, the clutch to be separated and the clutch to be engaged are independently controlled by adopting two groups of high-speed switch valve hydraulic half bridges, so that the power of an engine is stably transmitted, and the condition of transient power interruption or gear overlapping is avoided; and a double-pump double-loop system is adopted, when the plurality of groups of clutch hydraulic cylinders act, the double pumps respectively supply oil independently, and the synchronous action of the clutch hydraulic cylinders is ensured;
3. the digital hydraulic valve is directly controlled by a computer, an A/D conversion link is not needed, the clutches are grouped to form a control unit, the hydraulic cylinder of the clutch group adopts a multiplexing hydraulic half-bridge technology, performance parameters of all selected high-speed switch valves are consistent, a digital valve matrix is conveniently formed, and the whole control system is relatively simple;
4. the gear shifting system is provided with a redundancy design, when a certain path of high-speed switch valve hydraulic half-bridge fails, a redundancy pressure output loop can still ensure the normal work of the system, and the reliability of the system is further improved; the system is provided with a limp mode, when the whole system is in power failure, the vehicle is switched to advance or reverse 1-gear operation through a manual emergency valve, and a protection link is arranged in the manual emergency mode, so that the vehicle is prevented from being broken down due to manual misoperation, and the safety of the whole vehicle is improved;
5. in the high-speed switch valve type hydraulic half-bridge adopted by the invention, each hydraulic half-bridge can select different numbers of high-speed switch valve groups, and the more the number of the high-speed switch valve groups connected into the system is, the more the flow combination forms of the connected system are, the higher the resolution ratio of pressure regulation is, and the better the stability of vehicle gear shifting is.
The invention utilizes the digital hydraulic control technology to establish a hydraulic bridge circuit for the high-speed switch valve to form a digital hydraulic valve matrix, and has more control autonomy and flexibility. The clutches are grouped according to the gear composition of the vehicle, the hydraulic cylinder of the clutch group adopts a multiplex hydraulic half-bridge technology, and the controller autonomously decides the hydraulic resistance value of the high-speed switch valve matrix according to the feedback oil temperature and the clutch operating pressure signal, so that the torque of the engine is stably transmitted, and a more reasonable buffer characteristic curve is output. Thereby improving the gear shifting stability and riding comfort of the heavy vehicle.
Detailed Description
The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.
The invention is shown in figures 1 and 2: the hydraulic power unit, the controller and the digital clutch hydraulic cylinder group are included; the digital clutch hydraulic cylinder group comprises clutches C1, C2, C3, CL, CH and CR and a locking clutch CB;
the hydraulic power unit comprises a first pressure circuit P s1 And a second pressure circuit P s2 ;
The digital clutch hydraulic cylinder group divides the clutches C1, C2, C3, CL, CH, CR and the locking clutch CB into three groups, namely a gear number clutch group hydraulic cylinder C1, C2 and C3, a functional clutch group hydraulic cylinder CL, CH, CR and a locking clutch group hydraulic cylinder CB;
the hydraulic cylinders C1, C2 and C3 of the clutch group with the number of gears are respectively connected with first to third three-position five- way reversing valves 61, 62 and 63 in front, the hydraulic cylinders CL, CH and CR of the functional clutch group are respectively connected with fourth to sixth three-position five- way reversing valves 64, 65 and 66 in front, and the hydraulic cylinder CB of the locking clutch group is connected with a two-position three-way reversing valve 67 in front;
first pressure circuit P s1 The hydraulic half-bridges HSV1 and HSV2 are respectively connected with a port P1 and a port P2 of each reversing valve in the first three-position five- way reversing valves 61, 62 and 63; form a first and a second pressure output circuits P 1 、P 2 ;
Second pressure circuit P s2 The hydraulic half-bridge type A HSV3 and HSV4 are respectively connected with a port P1 and a port P2 of each reversing valve in the fourth three-position five-way reversing valve 64, the sixth three-position five-way reversing valve 65 and the sixth three-position five-way reversing valve 66; form a third and a fourth pressure output loop P 3 、P 4 ;
Second pressure circuit P s2 The hydraulic half-bridge HSV5 is also connected with a port P of the two-position three-way reversing valve 67; form a fifth pressure output circuit P 5 。
The hydraulic power unit provides high-pressure oil liquid required by gear shifting for the system, and the pressure requirement of a hydraulic cylinder of the gear shifting clutch is met; the controller is used for sampling the parameters of the gear shifting buffer hydraulic system and controlling the high-speed switch valve matrix and the electromagnetic valve according to a vehicle gear shifting instruction; the digital clutch hydraulic cylinder group controls the pressure boosting and releasing of oil in the clutch hydraulic cylinder by using the liquid resistance change of the high-speed switch valve half bridge, so that the clutch can stably transmit torque.
According to the gear combination logic of the transmission, the hydraulic cylinder group of the digital clutch is divided into three subgroups, which are respectively: a gear number clutch group, a functional clutch group and a locking clutch; the gear number clutch group is connected with the first pressure loop and used for gear number distribution, the functional clutch group is connected with the second pressure loop and used for high-speed gear, low-speed gear and reverse gear selection, the gear number clutch group, the functional clutch group and the first/second pressure loop form a double-pump double-loop control system, oil supply of the two loops is independent and does not affect each other, synchronous action is guaranteed during gear switching, the lockup clutch is connected with the second pressure loop, lockup control of the hydraulic torque converter is achieved, and the transmission is enabled to complete switching between hydraulic transmission and mechanical transmission.
The specific hydraulic connection form in the digital clutch hydraulic cylinder group is that the first pressure circuit P s1 Connected to ports P of the first/third high- speed switching valves 11, 12, and a second pressure circuit P s2 Is connected with the P ports of the fifth/seventh/ninth high- speed switching valves 31, 32, 33, and the A ports of the first/third/fifth/seventh/ninth high- speed switching valves 11, 12, 31, 32, 33 are connected with the P ports of the second/fourth/sixth/eighth/tenth high- speed switching valves 21, 22, 41, 42, 43, respectivelyAnd the ports a of the second/fourth/sixth/eighth/tenth high- speed switching valves 21, 22, 41, 42, 43 are connected to the tank 130, thereby forming:
the first high-speed switch valve 11 is a first A-type hydraulic half-bridge HSV1 with an input hydraulic resistance and the second high-speed switch valve 21 is an output hydraulic resistance;
the third high-speed switch valve 12 is a second A-type hydraulic half-bridge HSV2 with an input hydraulic resistance and the fourth high-speed switch valve 22 with an output hydraulic resistance;
the fifth high-speed switch valve 31 is a third a-type hydraulic half-bridge HSV3 with an input hydraulic resistance and the sixth high-speed switch valve 41 with an output hydraulic resistance;
the seventh high-speed switching valve 32 is a fourth a-type hydraulic half-bridge HSV4 with an input hydraulic resistance and the eighth high-speed switching valve 42 with an output hydraulic resistance;
the ninth high-speed switching valve 33 is a fifth a-type hydraulic half-bridge HSV5 with an input hydraulic resistance and the tenth high-speed switching valve 43 is an output hydraulic resistance;
the PWM control signal is used for controlling the rapid opening and closing of each high-speed switch valve in each hydraulic half bridge, so that the resistance values of the input liquid resistance and the output liquid resistance of each hydraulic half bridge are independently adjusted.
The port A of the first high-speed switch valve 11 is connected with the ports P1 of the first to third three-position five- way reversing valves 61, 62 and 63 to form a first pressure output loop P 1 ;
The port A of the third high-speed switch valve 12 is connected with the ports P2 of the first to third three-position five- way reversing valves 61, 62 and 63 to form a second pressure output loop P 2 ;
The port A of the fifth high-speed switch valve 31 is connected with the ports P1 of the fourth to sixth three-position five- way reversing valves 64, 65 and 66 to form a third pressure output loop P 3 ;
The A port of the seventh high-speed switch valve 32 is connected with the P2 ports of 64, 65 and 66 of the fourth-sixth three-position five-way reversing valve to form a fourth pressure output loop P 4 ;
The A port of the ninth high-speed switching valve 33 is connected to the P port of the two-position three-way selector valve 67 to form a fifth pressure output circuit P 5 。
The ports A and B of the first to third three-position five-way reversing valves 61, 62 and 63 are converged and then are respectively connected with the inlets of the clutch hydraulic cylinders C1, C2 and C3 with the gear numbers in a one-to-one correspondence manner, the ports A and B of the fourth to sixth three-position five-way electromagnetic reversing valves are converged and then are respectively connected with the inlets of the functional clutch hydraulic cylinders in a one-to-one correspondence manner, and the port A of the two-position three-way reversing valve 67 is connected with the inlet of the locking clutch hydraulic cylinder CB; when gears are switched, three-position five-way reversing valves corresponding to action hydraulic cylinders in the clutch group with different gear numbers are respectively positioned at different working positions, resistance values of input and output variable hydraulic resistors in the first/second A-type hydraulic half-bridges are independently adjusted, buffer pressure relief and buffer pressure boost control of the working hydraulic cylinders during switching of different gear numbers are realized, and middle positions of the first to third three-position five-way reversing valves 61, 62 and 63 are respectively connected with an oil tank and used for pressure relief of the middle position of the hydraulic cylinder of the clutch group with different gear numbers; meanwhile, three-position five-way reversing valves corresponding to the action hydraulic cylinders in the functional clutch group are respectively positioned at different working positions, the resistance values of input and output variable hydraulic resistors in a third/fourth A-type hydraulic half bridge are independently adjusted, the buffer pressure relief and buffer pressure boost control of the working hydraulic cylinders are realized when a low-speed gear, a high-speed gear and a reverse gear are switched, and the middle positions of fourth to sixth three-position five-way electromagnetic reversing valves 64, 65 and 66 are respectively connected with an oil tank and used for relieving pressure in the middle position of the hydraulic cylinders of the functional clutch group; when a vehicle sends a locking control instruction to the controller, the two-position three-way reversing valve 67 is electrified and switched to a working position, the controller independently adjusts the resistance value of the input/output variable hydraulic resistor in the fifth A-type hydraulic half bridge to realize locking control of the transmission, the critical locking vehicle speed is measured by a vehicle delivery test, and a T port of the two-position three-way reversing valve 67 is connected with an oil tank and used for releasing pressure of a locking clutch hydraulic cylinder when power is off;
in addition, in the clutch group with the number of gears and the functional clutch group, each clutch group comprises two pressure output loops, each clutch is provided with a three-position five-way reversing valve, and one pressure output loop is used for enabling the hydraulic cylinder to release pressure according to the control requirement when the three-position five-way reversing valve corresponding to the clutch to be separated is in a working position; the other pressure output circuit is used for boosting the hydraulic cylinder according to the control requirement when the three-position five-way reversing valve corresponding to the clutch to be engaged is at the other working position; in the gear shifting process, the two pressure output circuits act in a coordinated mode to finish torque smooth transition, and the three-position five-way reversing valve corresponding to the clutch which does not participate in the gear shifting operation is always in the middle position.
The invention also comprises a redundant oil circuit which comprises a redundant A-type hydraulic half-bridge HSV6, wherein the redundant A-type hydraulic half-bridge HSV6 is connected with the front end of the first pressure loop P s1 Then, connecting the first to fifth hydraulic shuttle valves 51 to 55 in parallel, wherein the first to fifth hydraulic shuttle valves 51 to 55 are correspondingly connected with the type A hydraulic half bridges HSV1, HSV2, HSV3, HSV4 and HSV5 one by one; form a sixth pressure output circuit P 6 。
Specifically, the port P of the eleventh high-speed switching valve 13 and the first pressure circuit P s1 In connection, the port a of the eleventh high speed switching valve 13 is connected to the port P of the twelfth high speed switching valve 23, and the port a of the twelfth high speed switching valve 23 is connected to the tank 130, thereby forming: the eleventh high-speed switch valve 13 is a sixth a-type hydraulic half-bridge HSV6 with an input hydraulic resistance and the twelfth high-speed switch valve 23 with an output hydraulic resistance; the port a of the eleventh high-speed switching valve 13 is further connected to the first/second/third/fourth/fifth hydraulic shuttle valves 51, 52, 53, 54, 55 located between the sixth a-type hydraulic half-bridge HSV6 and the first/second/third/fourth/fifth pressure output circuits (i.e. the aforementioned P1 to P5) to form the sixth pressure output circuit P6, which is used as a redundant pressure output circuit, when any of the first/second/third/fourth/fifth a-type hydraulic half-bridges (HSV 1 to HSV 5) fails, the controller automatically enables the redundant pressure output circuit, and the sixth a-type hydraulic half-bridge HSV6 reverses the hydraulic shuttle valve of the failed circuit to replace a variable hydraulic resistance in the failed circuit to supply oil to the failed circuit, thereby ensuring reliable operation of the system.
The emergency oil circuit comprises a first two-position three-way emergency valve 91, a second two-position three-way emergency valve 92 and a manual reversing valve 93;
first pressure circuit P s1 A P port connected with the first two-position three-way emergency valve 91, and a second pressure loop P s2 Is connected with the port P of the second two-position three-way emergency valve 92,
the A ports of the first and second two-position three- way emergency valves 91 and 92 are respectively connected with the P1 port and the P2 port of the manual reversing valve 93; the outlets of the manual directional valve 93 are respectively through:
the first emergency shuttle valve 56 is connected with a gear position clutch hydraulic cylinder C1;
the second emergency shuttle valve 57 is connected with a functional clutch hydraulic cylinder CL;
the third emergency shuttle valve 58 is connected with a functional clutch hydraulic cylinder CR;
the left position and the right position of the manual reversing valve 93 correspond to a forward (D) gear and a reverse (R) gear respectively, and correspond to a neutral gear (N) gear in the middle position.
As shown in fig. 1, 2 and 3, under the condition of normal power-on control, the manual emergency valve is arranged at the position of 'N', the first/second two-position three-way emergency valve is powered on, so that high-pressure oil in the first/second pressure loop cannot enter the manual emergency valve, the clutch hydraulic cylinder supplies oil through the pressure output loop of each a-type hydraulic half-bridge, and the emergency shuttle valve closes an oil path between the manual emergency valve and the clutch hydraulic cylinder; only under the condition of complete power loss, the vehicle enters a limp mode, high-pressure oil of a first pressure loop and a second pressure loop can pass through a P port of a first two-position three-way emergency valve and a P port and a P2 port of a manual reversing valve to be led to, if the manual emergency valve is in an R position, the high-pressure oil reaches positions corresponding to the first emergency shuttle valve and the third emergency shuttle valve to reverse the shuttle valves and switch to a reversing 1-gear limp mode, and if the manual emergency valve is in a D position, the high-pressure oil reaches positions corresponding to the first emergency shuttle valve and the second emergency shuttle valve to reverse the shuttle valves and switch to a forward 1-gear limp mode; due to the combined design of the two-position three-way emergency valve and the manual emergency valve in the limping mode, the accident fault of the vehicle caused by the fact that high-pressure oil is leaked to the two-position three-way emergency valve or a driver mistakenly operates the manual emergency valve (93) can be avoided.
As shown in fig. 2 and 4, each a-type hydraulic half bridge comprises a pair of two-position two-way normally-closed high-speed switching valves which are connected in series and have the same type, the dynamic performance of each high-speed switching valve is completely the same, 12 high-speed switching valves forming six a-type half bridges are respectively connected to a controller, and the controller controls the on-off of each high-speed switching valve through a PWM signal; the high-speed switch valves are arranged in an array form, and the valves are arranged at equal intervals to form a high-speed switch valve matrix.
Pressure sensors are respectively arranged at the front ends of the digital clutch hydraulic cylinder clutches C1, C2, C3, CL, CH and CR and the locking clutch CB, and the pressure sensors are connected with a controller;
the pressure sensor is used for detecting pressure values of the pressure output loops P1-P5, and the controller calculates an operation pressure value of the clutch hydraulic cylinder according to data collected by the pressure sensor and a relation between a detected pressure value of the pressure output loop calibrated by a factory and actual pressure of oil of the clutch hydraulic cylinder, and the operation pressure value is used as a feedback quantity of buffer pressure closed-loop control;
the controller also stores buffer characteristic parameters at least comprising data such as oil temperature, buffer time, a clutch target buffer pressure value and the like, and queries interpolation according to the detected temperature value and the current buffer time to obtain a target buffer pressure value which is used as a set value of buffer pressure closed-loop control;
the controller is in pressure closed-loop control, after comparing a target buffer pressure value with an actual working pressure value of the clutch hydraulic cylinder, the controller independently updates the initial opening time of two high-speed switching valves in the corresponding hydraulic half-bridge and the duty ratio of a PWM control signal, so that the net flow flowing into and out of the clutch hydraulic cylinder is stably changed according to a preset rule;
in an embodiment of the invention, after a controller receives a gear shifting instruction from a vehicle, a set value and a feedback value are compared, the duty ratios and the opening time of the PWM control signals of two hydraulic resistors in the A-type hydraulic half bridge are respectively updated according to the relation between the oil pressure of the clutch calibrated by a factory and the duty ratio of the PWM control signal of the high-speed switching valve, the input hydraulic resistor high-speed switching valve on a bridge arm controls the time and the flow of oil flowing into a hydraulic cylinder, and the output hydraulic resistor high-speed switching valve controls the time and the flow of the oil flowing out of the hydraulic cylinder, so that the net flow flowing into and out of the clutch hydraulic cylinder is stably changed according to a preset rule; when the clutch to be jointed is in the preparation stage, the oil liquid quickly flows into the clutch hydraulic cylinder to eliminate the gap between the friction plates of the clutch, at this time, the external intervention is not needed generally, only the hydraulic resistance high-speed switch valve is needed to be input to completely open the quick oil charge, and when the clutch to be jointed is in the buffer pressure closed-loop control, the pressure flow relation formula in the clutch hydraulic cylinder is used
It can be known that when the piston cavity volume of the clutch hydraulic cylinder
V cultch Equivalent bulk modulus of clutch hydraulic cylinder
β e At a certain time, the net flow in the hydraulic cylinder is regulated
q net The magnitude will change the pressure change rate in the clutch cylinder->
So that the pressure in the clutch cylinder meets the damping characteristic requirements.
The hydraulic power unit includes an engine 100, an oil tank 130, a temperature sensor 120, and first and second oil supply passages;
the first oil supply path sequentially comprises a first filter 102, a first hydraulic pump 103, a first electromagnetic overflow valve 101, a first filter 104 with a check valve, a first pressure gauge 105 and a first check valve 81;
the second oil supply path sequentially comprises a second filter 112, a second hydraulic pump 113, a second electromagnetic overflow valve 111, a second filter 114 with a check valve, a second pressure gauge 115 and a second check valve 82;
the engine 100 drives the first hydraulic pump 103 and the second hydraulic pump 113 simultaneously;
the temperature sensor 120 is connected to the oil tank, is used for detecting the temperature value of the oil, and is connected to the controller;
the two oil supply loops form similar and independent oil supply, and the first/second one-way valve isolates the digital clutch hydraulic cylinder group from the hydraulic power unit to protect the hydraulic power unit; a first pressure gauge and a second pressure gauge are connected between the first filter with the one-way valve and the second filter with the one-way valve and the digital clutch hydraulic cylinder group and are used for displaying pressure values on the loop; the first/second filter with the one-way valve in the loop is used for ensuring that when the filter is blocked, the oil can still normally flow from the one-way valve, and the reliability of the whole system is improved.
The first hydraulic pump 103 and the second hydraulic pump 113 are respectively connected with the first electromagnetic overflow valve 101 and the second electromagnetic overflow valve 111 in parallel, the controller determines the power-on and power-off states of the first electromagnetic overflow valve 101 and the second electromagnetic overflow valve 111 according to the action condition of a hydraulic cylinder of the vehicle gear-shifting clutch, the controller is used for limiting the highest pressure of the first pressure circuit and the second pressure circuit when the electromagnetic valves are powered off, the safety of the circuits is ensured, the first pressure circuit and the second pressure circuit are unloaded when the electromagnetic valves are powered on, the energy consumption is reduced, and the temperature of oil is reduced.
The invention discloses a control method of a high-speed switch valve matrix digital gear shifting buffer system, which comprises the following steps:
before gear shifting, the clutches to be separated are all in a locked state, and the three-position five-way reversing valve corresponding to the clutches is in a working position and is always kept in the working position;
after a gear shifting instruction is received, oil in a hydraulic cylinder of the clutch to be separated flows out through an output hydraulic resistance high-speed switch valve of a certain hydraulic half bridge in the clutch group; in the preparation stage, a PWM control signal with 20% duty ratio is given, so that the pressure of the clutch to be separated is slowly released, and the pressure reserve coefficient in the clutch is eliminated; in the torque stage, the clutch to be separated adopts open-loop control, the duty ratio of a PWM control signal is reduced according to a certain slope, when the torque stage is finished, the clutch to be separated is completely separated, and a three-position five-way reversing valve corresponding to the clutch to be separated is switched to a middle position;
when a gear-shifting instruction is sent out, a three-position five-way reversing valve corresponding to a clutch to be jointed is switched to another working position and is always kept at the position, oil flows into a hydraulic cylinder of the clutch to be jointed from another hydraulic half bridge in the clutch group, in a preparation stage, a PWM control signal with the duty ratio of 100% is input to a hydraulic resistance high-speed switching valve, a PWM control signal with the duty ratio of 0% is output to the hydraulic resistance high-speed switching valve, the clutch to be jointed is rapidly filled with oil to eliminate gaps between clutch friction plates, in a torque stage, the clutch to be jointed starts to slide and rub to transmit torque, a controller adjusts an initial control value and an increase rate of the duty ratio of the PWM control signal input to the hydraulic resistance high-speed switching valve in a closed loop mode according to a preset torque transfer rule, the method comprises the steps that the boosting rate of a clutch to be combined and the pressure relief rate of a clutch to be separated are synchronized, smooth alternate lapping of torque is achieved, in the inertia stage, the duty ratio of an input hydraulic resistance high-speed switch valve is automatically adjusted through pressure closed loop control, the boosting rate of the clutch to be combined is controlled, meanwhile, the opening time of the output hydraulic resistance high-speed switch valve and the duty ratio of a PWM control signal are automatically adjusted, so that pressure fluctuation in the clutch to be combined is reduced, the pressure change rate in the clutch is enabled to stably change according to a preset buffering rule, after a clutch friction plate to be combined rotates synchronously, the PWM control signal with the duty ratio of the input hydraulic resistance high-speed switch valve being 100% is given, the PWM control signal with the duty ratio of the output hydraulic resistance high-speed switch valve being 0% is given, a hydraulic cylinder of the clutch is rapidly boosted to system pressure, and certain pressure is reserved in the clutch;
in the process, if the clutch is always in a joint state, the corresponding three-position five-way reversing valve is always in a working position, after the joint pressure of the clutch reaches a set value, the electromagnetic overflow valve is instructed to be electrified so as to unload the hydraulic pump, energy consumption is saved, the temperature of the oil liquid is reduced, and when the pressure of the oil liquid of the clutch is reduced to be below a threshold value which ensures reliable joint of the clutch, the electromagnetic overflow valve is deenergized so as to supplement the reduction of the pressure of the oil liquid in the clutch.
Taking a certain type of hydraulic automatic transmission as an example, the combination logic of each clutch is shown in table 1, and the hydraulic automatic transmission of the type has 6 forward gears, 2 reverse gears and hydraulic torque converter locking control;
TABLE 1 Gear combination logic table for hydraulic automatic transmission of certain model
Note: the "+" in the table indicates clutch cylinder engagement;
taking the example of shifting from 1 gear to 2 gear, before shifting, a first pressure output loop (P1) is connected with a hydraulic cylinder of a clutch (C1) with the gear number through the right position of a first three-position five-way reversing valve (61), a third pressure output loop (P3) is connected with a hydraulic cylinder of a functional Clutch (CL) through the right position of a fourth three-position five-way reversing valve (64), the two clutches are both in a locking state, and the working positions of the two clutches and the working positions of the corresponding three-position five-way reversing valves are always kept; after a gear shifting instruction is received, oil in a hydraulic cylinder of the gear number clutch (C1) flows out through a second high-speed switch valve (21) in a first A-type hydraulic half-bridge (HSV 1), in a preparation stage, a PWM control signal with a small duty ratio is given to the second high-speed switch valve (21), the gear number clutch (C1) is slowly decompressed, a pressure reserve coefficient in the clutch is eliminated, the pressure of the gear number clutch (C1) is lower than the system pressure but the clutch can be reliably connected, power interruption is avoided, in a torque stage, the gear number clutch (C1) is controlled in an open loop mode, the duty ratio of the PWM control signal of the second high-speed switch valve (21) is reduced according to a certain slope, reasonable lap joint of torque transmission of the two clutches is completed after the gear number clutch (C2) works in a matched mode with the boosting control, power overlapping is avoided, after the gear number clutch (C1) is completely separated, a three-position five-way reversing valve (61) is switched to a middle position friction plate, the gear number clutch (C1) is ensured to be reliably separated, and then only the pressure in the gear number clutch (C2) is controlled independently to operate synchronously; when a gear shifting command is sent, the three-position five-way reversing valve (62) is switched to the left position and is kept at the left position all the time, oil flows into a hydraulic cylinder of the gear number clutch (C2) from a second A-type hydraulic half bridge (HSV 2), in a preparation stage, a PWM control signal with the duty ratio of 100% is given to a third high-speed switch valve (12), a PWM control signal with the duty ratio of 0% is given to a fourth high-speed switch valve (22), so that the hydraulic cylinder of the gear number clutch (C2) is rapidly filled with oil to eliminate gaps between clutch friction plates, in a torque stage, the gear number clutch (C2) starts to slip and transmit torque, and a controller adjusts an initial control value and an increasing rate of the duty ratio of the PWM control signal input to the third high-speed switch valve (12) in a closed-loop mode according to a preset torque transfer rule, the boosting rate of the gear number clutch (C2) and the pressure relief rate of the gear number clutch (C1) are synchronized to realize smooth alternate lapping of torque, in an inertia stage, the duty ratio of the third high-speed switch valve (12) is automatically adjusted through pressure closed-loop control to control the boosting rate of the gear number clutch (C2), the opening time of the fourth high-speed switch valve (22) and the duty ratio of a PWM control signal are automatically adjusted to reduce pressure fluctuation in a hydraulic cylinder of the gear number clutch (C2), so that the pressure change rate of the gear number clutch (C2) is stably changed according to a preset buffering rule, and after a friction plate of the gear number clutch (C2) to be subjected to synchronous rotation, the PWM control signal with the duty ratio of 100% is given to the third high-speed switch valve (12), a PWM control signal with the duty ratio of 0% is sent to a fourth high-speed switch valve (22), and a hydraulic cylinder of a gear number clutch (C2) is quickly boosted to the system pressure, so that a certain pressure is reserved in the clutch, and the clutch is reliably engaged under different working conditions such as sudden external load change and the like; in the process, the functional Clutch (CL) is always in a joint state, the three-position five-way reversing valve (64) is always in a right position, the third A-type hydraulic half bridge (HSV 3) is in a normally closed state, and after the joint pressure of the functional Clutch (CL) reaches a set value, the second electromagnetic overflow valve (111) can be electrified, so that the second hydraulic pump (113) is unloaded, the energy consumption is saved, the oil temperature is reduced, when the oil pressure of the functional Clutch (CL) is reduced to be below a threshold value for ensuring the reliable joint of the clutch, the second electromagnetic overflow valve (111) is deenergized, the second pressure loop (Ps 2) provides high-pressure oil for the third A-type hydraulic half bridge (HSV 3) again, and the reduction of the oil pressure of the functional Clutch (CL) is supplemented;
in the gear-up process, the gear-up of the transmission is completed in sequence, the three-position five-way reversing valve corresponding to each clutch hydraulic cylinder alternately acts, and the power supply condition of the electromagnet is shown in table 2; during the downshift, a skip is allowed, and the action of the solenoid valve during the downshift is similar to that during the upshift.
TABLE 2 solenoid valve behavior during operation in each gear
Note: in the table, "L" represents that the electromagnetic valve is communicated at the left position, and "R" represents that the electromagnetic valve is communicated at the right position, and unsigned representation indicates that the electromagnetic valve is at the middle position;
finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described above, or equivalents may be substituted for elements thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.