CN110701299A - AMT solenoid valve driving device - Google Patents

Abstract

The invention provides an AMT electromagnetic valve driving device which can ensure that a driving circuit can be quickly cut off when a fault occurs. The electromagnetic valve switching device is used for controlling the on-off of M electromagnetic valves in a system and comprises M high-side switches connected with a power supply end and N low-side switches connected with a ground end, wherein M is larger than N; the M high-side switches control the on-off of the electromagnetic valves one by one; each low-side switch controls the on-off of at least one electromagnetic valve and is connected with the corresponding high-side switch of the electromagnetic valve in series; any one electromagnetic valve is correspondingly provided with only one low-side switch, so that the high-end current load is uniformly distributed on each low-side switch, and when any one low-side switch is opened, the basic gear can be engaged, and the normal operation of the gearbox is ensured; the low-side switch is normally closed and is controlled by adopting a watchdog circuit; when the control instruction to the high-side switch is 'off', the watchdog circuit detects whether the state of the high-side switch reaches the expectation, and if not, the low-side switch is controlled to 'off'.

Description

AMT solenoid valve driving device

Technical Field

The invention belongs to the control technology of a gearbox electromagnetic valve, and particularly relates to an AMT electromagnetic valve driving device.

Background

The AMT realizes automatic gear shifting through a gear selecting and shifting actuating mechanism and a clutch separating actuating mechanism on the basis of a mechanical gearbox. In the AMT control system, the electromagnetic valve drives the gear selecting and shifting actuating mechanism and the clutch separating actuating mechanism to realize the automatic gear shifting of the transmission, so the reliability of the electromagnetic valve determines the gear shifting quality of the whole AMT system. The existing heavy commercial vehicle mostly adopts a pneumatic actuating mechanism, namely, the air inlet and the air outlet of an air cylinder are controlled through an electromagnetic valve, so that a shifting fork shaft is moved.

With the rapid development of automobile electric control technology, automobile electromagnetic valves are also being updated, and in recent years, the requirement of people on functional safety is increased, and higher requirements are put forward on the design of a Transmission Controller (TCU). In a Transmission Controller (TCU), a plurality of electronic components are arranged, and not only is an electromagnetic valve driving circuit realized, but also multi-channel sensor signal acquisition is realized. In a complex circuit board, it is inevitable that a malfunction or interference occurs, and even the solenoid valve itself may malfunction. Once a fault occurs, gears cannot be switched, a clutch cannot be separated, and the like, which cause serious damage to drivers and pedestrians.

At present, a high-side switch is adopted to control the on-off of an electromagnetic valve, the high-side switch is connected with a power supply end, and application layer software can directly control the high-side switch to achieve gear control, so that under the normal condition, the gear switching is determined by the on-off of the high-side switch. However, when the high-side switch is unexpectedly closed and cannot be rapidly switched off, risks and hazards of unexpected acceleration, unexpected deceleration and the like are often daunting.

Therefore, there is still a need to develop a safer and more reliable AMT solenoid valve driving device.

Disclosure of Invention

In order to ensure that a driving circuit can be quickly cut off when a system fails and prevent dangers from happening, the invention provides an AMT electromagnetic valve driving device.

The invention conception of the application is as follows:

the functional safety standard ISO26262 sets forth a series of requirements for software, such as verification, backup, mirroring, echo, etc. In addition, there are functional safety requirements that can be directly optimized on the electronic device, such as increasing the reliability of the electronic device or adding redundant devices. The low-side switch is added in a driving circuit of the solenoid valve and is used as a safety switch in the driving circuit, and when the high-side switch is unexpectedly closed and can not be rapidly cut off, the low-side switch can rapidly respond to the cut-off circuit. Meanwhile, the factor of chip resource limitation is considered, so that the number of low-side switches is expected to be as small as possible, a plurality of electromagnetic valves are controlled in groups, and the function loss of the transmission is ensured to be minimum. The grouping principle needs to fully consider the even distribution of high-end load current to prevent overheating, and simultaneously needs to consider a gear-electromagnetic valve map to ensure that when any low-side safety switch is turned on, the basic gear of the gearbox can be engaged, and the vehicle can normally run in a limp-home mode.

The specific technical scheme of the invention is as follows:

an AMT electromagnetic valve driving device is used for controlling the on-off of M electromagnetic valves in a system and is characterized by comprising M high-side switches for connecting a power supply end and N low-side switches for connecting a ground end, wherein M is larger than N;

the M high-side switches are respectively arranged in the driving circuits of the M electromagnetic valves and control the on-off of the electromagnetic valves in a one-to-one manner;

each low-side switch controls the on-off of at least one electromagnetic valve and is connected with the corresponding high-side switch of the electromagnetic valve in series; any one electromagnetic valve is correspondingly provided with only one low-side switch (namely, the electromagnetic valves controlled by the low-side switches are different), so that the high-end current load is ensured to be uniformly distributed to the low-side switches, and when any one low-side switch is opened, the basic gear can be engaged, so that the normal operation of the gearbox is ensured;

the high-side switch is directly controlled by application layer software, the low-side switch is controlled by a watchdog circuit, and the low-side switch is normally closed; when the control instruction to the high-side switch is 'off', the watchdog circuit detects whether the state of the high-side switch reaches the expectation (namely whether the high-side switch is switched to the 'off' state), and if not, the low-side switch is controlled to be 'off'.

Furthermore, the number of the electromagnetic valves is 16, and the electromagnetic valves are respectively as follows: VG1, VG2 controlling gear engagement; VSE1 and VSE2 for controlling gear selection; VSP1, VSP2 that control half-gears; VR1, VR2 for control range gears; controlling the VTB of the intermediate shaft brake; VCEF, VCOS, VCCS, VCCF for controlling the clutch actuator; VPTO1, VPTO2 controlling the power take-off; and a standby solenoid valve VBackup;

the number of the low-side switches is 6, and the low-side switches are respectively as follows: LSS1, LSS2, LSS3, LSS4, LSS5, LSS 6;

wherein LSS1 is connected with VG1, VR2 and VSP 2;

LSS2 is connected with VG2, VSE2 and VR 1;

LSS3 connects VSE1, VSP1 and VTB;

LSS4 connects VCEF and VCCF;

LSS5 connects VCOS and VCCS;

LSS6 connects VPTO1, VPTO2 and VBackup.

The invention has the advantages that:

1. the mode that the high-side switch and the low-side switch are matched to drive the electromagnetic valve is adopted, so that the safety and the reliability of the electromagnetic valve are improved; under normal conditions, the high-side switch is connected with a power supply end to directly control the on-off of the electromagnetic valve, the low-side switch is grounded and is in a closed state, and the low-side switch is opened only under the conditions that unexpected faults occur on the high side and the power supply cannot be quickly cut off, so that the purpose of quickly removing the faults is achieved; the low-side switch can also load a PWM control signal to resist the current disturbance of the electromagnetic valve. Meanwhile, the problem of chip resources is considered, so that limited low-side switches are used for group control, the basic gear can be engaged when any one low-side switch is turned on, the normal operation of the gearbox is guaranteed, and the function loss is minimum.

2. For AMT systems with different gear numbers, an optimal grouping scheme is planned according to a grouping principle, and the number of low-side switches is determined, so that the purpose of improving the safety and reliability of the electromagnetic valve is achieved. For a 16-gear AMT system, an optimal grouping scheme is determined according to a grouping principle, and the aim of the invention can be achieved only by using 6 low-side switches, so that the design requirement is met, and the design cost is controlled.

Drawings

FIG. 1 is a diagram of the positions of the gears of a 16-gear AMT system;

FIG. 2 is a schematic diagram of a main box gear selecting and engaging direction;

fig. 3 is a solenoid valve driving circuit.

Detailed Description

The invention is described in detail below with reference to the following figures and specific examples:

for adding a low-side switch in the gearbox, the key point is how to achieve the optimal grouping, and the gearbox can be ensured to be hung with necessary gears after the fault is eliminated, and then the gearbox limps home.

So in principle, the grouping scheme should consider the following two points:

1. the high-side current load should be evenly distributed to the limited low-side switches to prevent overheating;

2. the gear-electromagnetic valve map is fully considered, so that when each group of low-side switches is turned on, the basic gear can be engaged, and the normal operation of the gearbox can be ensured (namely the basic gear of the gearbox can be engaged, and the vehicle can also normally operate in a limp mode).

The quality of the grouping scheme obviously determines the fault tolerance of the gearbox.

Therefore, the application takes a 16-gear AMT gearbox as an example, and designs an optimal low-side safety switch grouping scheme according to a 16-gear AMT solenoid valve gear shifting mechanism.

First, a 16-gear AMT transmission usually adopts a three-stage structure, including 4 gears of a main box (respectively, main box 1, main box 2, main box 3, and main box 4), a reverse gear, and 2 gears of front and rear auxiliary boxes, and the positions of the gears are specifically shown in fig. 1.

The transmission case has 16 electromagnetic valves which respectively complete free actions such as gear selection, gear engagement, range gear, half gear, intermediate shaft brake, clutch, PTO and the like, and the functions of the electromagnetic valves are shown in Table 1:

TABLE 1

As shown in table 1, there are 2 electromagnetic valves for each of the gear engagement, gear selection, range gear and half gear, and 1 electromagnetic valve for the countershaft brake, where gear engagement VG1 controls the shift fork shaft to extend outward, gear engagement VG2 controls the shift fork shaft to retract inward, and when 2 electromagnetic valves are simultaneously operated, the gear is in the middle; the range gear VR1 controls low gear, and the VR1 controls high gear; the working principle of the half gear is the same as that of the range gear; the intermediate shaft brake only has 1 electromagnetic valve VTB to control air inflow of the cylinder so as to rapidly reduce the rotating speed of the input shaft.

Based on the above distribution principle, in order to distribute the high-side current loads evenly, every 3 groups of the solenoid valves are connected to the ground through the low-side switch, and the low-side switch is connected with the high-side switch corresponding to the solenoid valve controlled by the low-side switch in series and is controlled by the watchdog circuit. The gear selecting extending direction is the left side when viewed from the front to the back of the gearbox, and the gear selecting retracting direction is the right side. In design, when the VSE1 and the VSE2 act simultaneously, the gear selection is in the middle position, namely, any gear selection electromagnetic valve fails, and the gear selection direction cannot return to the middle position. Therefore, the shift stage with the lowest frequency of use should be placed in the middle position in theory. In consideration, in order to reduce the failure rate, the gear selection middle position is set as a reverse gear working position (because the middle position needs 2 electromagnetic valves to act simultaneously, any one electromagnetic valve cannot be kept at the middle position when damaged), and the reverse gear using frequency is low, so that the reverse gear is placed at the gear selection middle position; 1/2 is in the extended direction and 3/4 is in the retracted direction, as shown in FIG. 2, with the arrow indicating the extended direction.

The clutch actuating mechanism comprises 4 driving electromagnetic valves which are divided into a quick opening VCEF, a quick closing VCCS, a slow opening VCOS and a slow closing VCCF, and the grouping principle is that a quick valve and a slow valve are respectively in one group, so that at least one group of air inlet electromagnetic valves and exhaust electromagnetic valves normally close and open the clutch no matter any fault occurs.

While the other power take-off solenoid valves VPTO1, VPTO2 and the backup solenoid valve VBackup are placed in a group because no gear shifting of the gearbox is involved.

In summary, the 16 solenoid valves can be divided into 6 groups, and the grounding is performed through 6 low-side switches, and the grouping conditions are shown in table 2:

TABLE 2

That is, the final confirmation low-side switch grouping method is as follows:

LSS1:VG1+VR2+VSP2

LSS2:VG2+VSE2+VR1

LSS3:VSE1+VSP1+VTB

LSS4:VCOF+VCCF

LSS5:VCOS+VCCS

LSS6:VPTO1+VPTO2+VBackup

according to the low-side switch grouping mode, the minimum gear loss when a fault occurs is achieved. The driving circuit design is shown in fig. 3, where HSS is the high-side switch and LSS is the low-side switch.

Claims (2)

1. The utility model provides an AMT solenoid valve drive arrangement for the break-make of M solenoid valves in the control system, its characterized in that: the circuit comprises M high-side switches for connecting a power supply end and N low-side switches for connecting a ground end, wherein M is larger than N;

the M high-side switches are respectively arranged in the driving circuits of the M electromagnetic valves and control the on-off of the electromagnetic valves in a one-to-one manner;

each low-side switch controls the on-off of at least one electromagnetic valve and is connected with the corresponding high-side switch of the electromagnetic valve in series; any one electromagnetic valve is correspondingly provided with only one low-side switch, so that the high-end current load is uniformly distributed on each low-side switch, and when any one low-side switch is opened, the basic gear can be engaged, and the normal operation of the gearbox is ensured;

the high-side switch is directly controlled by application layer software, the low-side switch is controlled by a watchdog circuit, and the low-side switch is normally closed; when the control instruction to the high-side switch is 'off', the watchdog circuit detects whether the state of the high-side switch reaches the expectation, and if not, the low-side switch is controlled to 'off'.

2. An AMT solenoid valve driving device according to claim 1, wherein: the number of the electromagnetic valves is 16, and the electromagnetic valves are respectively as follows: VG1, VG2 controlling gear engagement; VSE1 and VSE2 for controlling gear selection; VSP1, VSP2 that control half-gears; VR1, VR2 for control range gears; controlling the VTB of the intermediate shaft brake; VCEF, VCOS, VCCS, VCCF for controlling the clutch actuator; VPTO1, VPTO2 controlling the power take-off; and a standby solenoid valve VBackup;

the number of the low-side switches is 6, and the low-side switches are respectively as follows: LSS1, LSS2, LSS3, LSS4, LSS5, LSS 6;

wherein LSS1 is connected with VG1, VR2 and VSP 2;

LSS2 is connected with VG2, VSE2 and VR 1;

LSS3 connects VSE1, VSP1 and VTB;

LSS4 connects VCEF and VCCF;

LSS5 connects VCOS and VCCS;

LSS6 connects VPTO1, VPTO2 and VBackup.

Images