A master-slave braking control system and method for heavy-duty vehicles

Abstract

The present invention belongs to the technical field of primary and secondary braking control, and specifically provides a primary and secondary braking control system and method for heavy-duty vehicles. The system includes that an ECU is connected to a conversion relay through a brake light switch; the conversion relay is connected to a pneumatic signal switch; the pneumatic signal switch is arranged at the air source interface position of the secondary brake master valve, and when the secondary brake master valve connects to the air source, the pneumatic signal switch closes; the ECU is connected to a brake light through a controller B; the brake light switch is connected to the control end of the primary brake master valve; the brake light switch is sequentially connected to the secondary brake master valve through the conversion relay and the pneumatic signal switch; the primary brake master valve is connected to the secondary brake master valve through a two-position three-way solenoid valve; the control ends of the two-position three-way solenoid valve are respectively connected to the pneumatic signal switch and a rocker switch. The secondary brake also realizes electric control and can cooperate with the vehicle ECU and the controller B to realize functions such as engine fuel cut-off, engine braking judgment, and driving brake light lighting.

Description

Technical Field

[0001] The present invention relates to the technical field of primary and secondary braking control, and particularly to a primary and secondary braking control system and method for heavy-duty vehicles. Background Art

[0002] With the development of automotive technology, there are increasingly high requirements for the electrification level of vehicles, and at the same time, more attention is paid to vehicle safety. Vehicle safety has thus become an important guarantee for people's lives and property safety.

[0003] Heavy-duty vehicles refer to category M and N vehicles with a maximum total mass greater than 3500 Kg. This type of vehicle consists of a heavy-duty tractor and a heavy-duty trailer. This type of vehicle generally uses a multi-axle series hydraulic suspension device and is generally used to transport large cargoes whose size and weight exceed the limits specified by road traffic regulations. That is to say, heavy-duty vehicles are heavy, have relatively high requirements for the braking performance of the vehicle itself, and when used as training vehicles for driver training, in order to improve the learning efficiency of trainees, enhance driving safety, and reduce the use costs of coaches and vehicles, the electrification improvement of the secondary braking system of training vehicles is extremely urgent. That is, the vehicle itself needs to be equipped with a secondary braking device so that the coach can control vehicle braking on the co-driver side and avoid the occurrence of safety accidents.

[0004] At present, the secondary braking of heavy-duty vehicles mainly controls the primary brake pedal through a mechanical structure or controls it by paralleling a secondary brake master valve in the braking circuit. The secondary braking of the mechanical structure generally requires a lever, a steel cable or an electromagnetic coil to achieve. Such a structure is inconvenient to install and has general versatility due to different body structures; when paralleling the secondary brake master valve, the working principle of the secondary brake is the same as that of the primary brake, which is convenient to install and has reliable braking performance and is not affected by the body structure, but lacks an anti-misoperation device. Summary of the Invention

[0005] At present, the secondary braking of heavy-duty vehicles mainly controls the primary brake pedal through a mechanical structure or controls it by paralleling a secondary brake master valve in the braking circuit. The secondary braking of the mechanical structure generally requires a lever, a steel cable or an electromagnetic coil to achieve. Such a structure is inconvenient to install and has general versatility due to different body structures; when paralleling the secondary brake master valve, the working principle of the secondary brake is the same as that of the primary brake, which is convenient to install and has reliable braking performance and is not affected by the body structure, but lacks an anti-misoperation device. In view of this, the present invention provides a primary and secondary braking control system and method for heavy-duty vehicles.

[0006] In a first aspect, the technical solution of the present invention provides a primary and secondary braking control system for heavy-duty vehicles, including a primary brake master valve, a secondary brake master valve, an ECU, and a rocker switch;

[0007] The ECU is connected to a conversion relay through a brake light switch;

[0008] The conversion relay is connected to a pneumatic signal switch; the pneumatic signal switch is arranged at the air source interface position of the auxiliary brake master valve. When the auxiliary brake master valve is connected to the air source, the pneumatic signal switch is closed.

[0009] The ECU is connected to a brake light through controller B.

[0010] The brake light switch is connected to the control end of the main brake master valve.

[0011] The brake light switch is connected to the auxiliary brake master valve through the conversion relay and the pneumatic signal switch in sequence.

[0012] The main brake master valve is connected to the auxiliary brake master valve through a two-position three-way solenoid valve.

[0013] The control ends of the two-position three-way solenoid valve are respectively connected to the pneumatic signal switch and the rocker switch.

[0014] As a preference of the technical solution of the present invention, the two-position three-way solenoid valve includes a first two-position three-way solenoid valve connected to the first air source interface of the auxiliary brake master valve and a second two-position three-way solenoid valve connected to the second air source interface of the auxiliary brake master valve.

[0015] The system further includes a front axle service air reservoir and a rear axle service air reservoir.

[0016] The front axle service air reservoir is respectively connected to the first air source interface of the main brake master valve and the first air source interface of the auxiliary brake master valve.

[0017] The rear axle service air reservoir is respectively connected to the second air source interface of the main brake master valve and the second air source interface of the auxiliary brake master valve.

[0018] The first air source interface of the main brake master valve is respectively connected to the first two-position three-way solenoid valve and the second two-position three-way solenoid valve through a first double-check non-return valve.

[0019] The second air source interface of the main brake master valve is respectively connected to the first two-position three-way solenoid valve and the second two-position three-way solenoid valve through a second double-check non-return valve.

[0020] As a preference of the technical solution of the present invention, the first double-check non-return valve is connected to an EBS front axle module.

[0021] The EBS front axle module is connected to a first front axle brake chamber through a first front axle ABS solenoid valve.

[0022] The EBS front axle module is connected to a second front axle brake chamber through a second front axle ABS solenoid valve.

[0023] As a preference of the technical solution of the present invention, the second double-check non-return valve is connected to an EBS rear axle module.

[0024] The EBS rear axle module is connected with a first rear axle brake air chamber and a second rear axle brake air chamber.

[0025] As a preference of the technical solution of the present invention, the air pressure signal switch is connected with the secondary brake master valve through a tee.

[0026] As a preference of the technical solution of the present invention, the system further includes a combined instrument respectively connected with the controller B and the ECU, which is used for receiving the message sent by the ECU, the instrument displays the ECU fault, after the controller B detects that the brake lamp loop is normal, it drives the brake lamp to light up, and the instrument outputs a brake diagram.

[0027] The air pressure signal switch is connected at the air source interface position of the secondary brake master valve through a tee. When the secondary brake works, the air pressure signal switch is closed, the normally closed switch of the conversion relay is disconnected, and the normally open switch is closed. The normally open switch loop connected by the conversion relay is conducted with the main brake brake lamp switch, and a signal is output to the main brake switch pin of the ECU; two two-way three-way valves are added in the secondary brake air circuit to control the on-off of the front and rear axle air circuits of the secondary brake. The two two-way three-way valves are connected in parallel and are normally open, and are controlled by a rocker switch. When the rocker switch is turned on, the two-way three-way solenoid valve is closed, and the secondary brake function is turned off; when the main and secondary brakes work simultaneously, the normally closed contact of the brake lamp switch is disconnected and the normally open contact is conducted, the air pressure signal switch is closed, the normally closed switch of the conversion relay is disconnected and the normally open switch is conducted, the main brake switch pin of the ECU is at a high level, the secondary brake switch pin of the ECU is suspended, the logic judgment is normal, and a brake message can be output; when the secondary brake works, the main brake switch pin of the ECU is at a high level, the secondary brake switch pin of the ECU is suspended, the ECU judges that the brake function is normal, and outputs a brake message to the controller B and the instrument. After the controller B detects that the brake lamp loop is normal, it drives the brake lamp to light up, and the instrument outputs a brake diagram.

[0028] In the second aspect, the technical solution of the present invention further provides a main and secondary brake control method for a heavy-duty vehicle, including the following steps:

[0029] When the secondary brake pedal is depressed and the main brake pedal is not depressed, the secondary brake master valve is opened, compressed air passes from the front / rear axle service air reservoir through the secondary brake master valve to the front / rear axle double-check non-return valve. According to the different air pressures, the spool of the front / rear axle double-check non-return valve moves, so that the air circuit with a higher air pressure passes through the output port of the front / rear axle double-check non-return valve and enters the EBS front axle module and the EBS rear axle module, and respectively enters the front axle brake air chamber and the rear axle brake air chamber through the control of the EBS front axle module and the EBS rear axle module to perform a braking action;

[0030] When the air pressure at the air source interface is greater than the set threshold after the auxiliary brake master valve is opened, the air pressure signal switch installed on the tee of the air source interface closes, the normally closed switch of the conversion relay operates and disconnects, and the normally open switch closes. Since the main brake pedal is not depressed, the brake light switch is in the normally closed state at this time. The ECU electrical signal passes through the normally closed switch of the brake light switch to the normally open switch closed by the conversion relay and then returns to the ECU main brake switch pin. At this time, the normally closed switch of the conversion relay disconnects, so the auxiliary brake switch pin is floating;

[0031] After the auxiliary brake master valve is opened, the air pressure signal switch closes. After the conversion relay operates, the ECU main brake switch signal is pulled low. The engine power output passes through the brake light switch and the conversion relay and then inputs the brake signal to the ECU auxiliary brake switch, and the ECU judges the brake signal;

[0032] When the judgment is unreasonable, the ECU sends a fault message to display the ECU fault through the instrument;

[0033] When the judgment is reasonable, the ECU cuts off the fuel supply and limits the torque, and sends a brake message. Controller B receives the brake message and drives to detect whether the brake light is faulty. If there is no fault, Controller B drives the brake light to light up, and at the same time sends a brake light status message to the instrument, and the instrument brake light indicator lights up; if there is a fault, Controller B sends a fault status message to the instrument, and the instrument reports a fault of Controller B.

[0034] As an optimization of the technical solution of the present invention, the method further includes:

[0035] When the main brake pedal is depressed and the auxiliary brake pedal is not depressed, the main brake master valve opens, and compressed air passes from the front / rear axle service air storage tank through the main brake master valve to the front / rear axle two-way check valve. According to the different air pressures, the spool of the front / rear axle two-way check valve moves, so that the air path with higher air pressure passes through the output port of the front / rear axle two-way check valve and outputs into the EBS front axle module and the EBS rear axle module, and respectively enters the front axle brake chamber and the rear axle brake chamber through the control of the EBS front axle module and the EBS rear axle module to perform braking actions;

[0036] When the main brake pedal is depressed, the elastic hoop fixed to the main brake pedal moves with the main brake pedal. When the elastic hoop moves to a distance less than the first threshold from the brake light switch, the normally open contact of the brake light switch is closed, and the normally closed contact of the brake light switch is opened. The electrical signal output by the ECU returns to the ECU through the closed normally open contact of the brake light switch. At this time, the air pressure signal switch is disconnected, the conversion relay does not work, and the normally closed switch of the conversion relay is in the closed state at this time, and the ECU auxiliary brake pin is floating;

[0037] When the main brake master valve is opened, the brake light switch inputs the main and auxiliary brake signals to the ECU through the conversion relay, and the ECU judges the brake signal;

[0038] When the judgment is unreasonable, the ECU sends a fault message, and the instrument displays an ECU fault;

[0039] When the judgment is reasonable, the ECU cuts off fuel supply and limits torque, and sends a braking message. Controller B receives the braking message and drives to detect whether the braking light is faulty. If there is no fault, Controller B drives the braking light to light up, and at the same time sends a braking light status message to the instrument, and the instrument braking light indicator lights up; if there is a fault, Controller B sends a fault status message to the instrument, and the instrument reports a Controller B fault.

[0040] As a preference of the technical solution of the present invention, the method further includes:

[0041] When the main brake pedal and the auxiliary brake pedal are stepped on simultaneously, the main brake master valve and the auxiliary brake master valve are opened simultaneously. Compressed air passes from the front / rear axle service air reservoirs through the main brake master valve and the auxiliary brake master valve to the front / rear axle double-check non-return valve. The compressed air in the main brake air circuit and the compressed air in the auxiliary brake air circuit are compared in air pressure at the position of the front / rear axle double-check non-return valve. The brake air circuit with higher air pressure enters the EBS front axle module and the EBS rear axle module through the front / rear axle double-check non-return valve, and after being controlled by the EBS front axle module, enters the front axle brake air chamber through the front axle ABS solenoid valve for braking, and after being controlled by the EBS rear axle module, enters the rear axle brake air chamber for braking;

[0042] When the main brake pedal is stepped on, the elastic hoop fixed to the main brake pedal moves with the main brake pedal; when the elastic hoop moves to a distance less than the first threshold from the brake light switch, the normally open contact of the brake light switch is closed, and the normally closed contact of the brake light switch is opened. The electrical signal output by the ECU returns to the ECU main brake switch pin through the normally open contact closed by the brake light switch; since the auxiliary brake master valve is opened, the air pressure signal switch installed on the tee of the auxiliary brake master valve air source interface is closed, the conversion relay operates to close the normally open switch and open the normally closed switch. At this time, the electrical signal output by the ECU returns to the ECU main brake switch pin through the normally open contact closed by the brake light switch. Since the normally closed switch of the conversion relay is open, the ECU auxiliary brake switch pin is floating.

[0043] As a preference of the technical solution of the present invention, the method further includes:

[0044] When the main brake master valve and the auxiliary brake master valve are opened simultaneously, the brake light switch inputs the main brake signal output by the engine power supply to the ECU through the conversion relay. At this time, the air pressure signal switch is closed, the conversion relay operates, and the auxiliary brake signal inputs a low-level signal to the ECU through the brake light switch and the conversion relay. The ECU makes a braking signal judgment;

[0045] When the judgment is unreasonable, the ECU sends a fault message, and the instrument displays an ECU fault;

[0046] When the judgment is reasonable, the ECU cuts off the fuel supply and limits the torque, and sends a braking message. Controller B receives the braking message and drives to detect whether the braking lamp is faulty. If there is no fault, Controller B drives the braking lamp to light up, and at the same time sends a braking lamp status message to the instrument, and the instrument braking lamp indicator lights up; if there is a fault, Controller B sends a fault status message to the instrument, and the instrument reports a fault of Controller B.

[0047] As can be seen from the above technical solutions, the present invention has the following advantages:

[0048] (1) The secondary brake also realizes electronic control, and can cooperate with the vehicle ECU and Controller B to realize functions such as engine fuel cut-off, engine braking judgment, and driving the braking lamp to light up.

[0049] (2) When the secondary braking function is not required, the rocker switch can turn off the secondary brake without affecting the primary brake function.

[0050] (3) The braking logic judgment of the controller is normal when the primary and secondary braking functions work simultaneously.

[0051] (4) When the secondary braking function works, it can drive the braking lamp to light up.

[0052] In addition, the design principle of the present invention is reliable, the structure is simple, and it has a very wide application prospect.

[0053] Thus, compared with the prior art, the present invention has outstanding substantive features and remarkable progress, and the beneficial effects of its implementation are also obvious. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to these drawings.

[0055] Figure 1 is the schematic diagram of the primary and secondary braking control system of an embodiment of the present invention.

[0056] Figure 2 is the schematic connection diagram of the ECU of an embodiment of the present invention.

[0057] Among them, 1 - front axle service air reservoir, 2 - rear axle service air reservoir, 3 - brake light switch, 4 - main brake master valve, 5 - first front axle brake chamber, 6 - second front axle brake chamber, 7 - first front axle ABS solenoid valve, 8 - second front axle ABS solenoid valve, 9 - EBS front axle module, 10 - first two-way three-way solenoid valve, 11 - first double-check valve, 12 - second double-check valve, 13 - EBS rear axle module, 14 - first rear axle brake chamber, 15 - second rear axle brake chamber, 16 - rocker switch, 17 - combination instrument, 18 - tractor brake light, 19 - trailer brake light, 20 - controller B, 21 - second two-way three-way solenoid valve, 22 - conversion relay, 23 - ECU, 24 - secondary brake master valve. Detailed implementation manner

[0058] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0059] As Figure 1 and 2 shown, the embodiment of the present invention provides a main and secondary brake control system for a heavy-duty vehicle, including a main brake master valve 4, a secondary brake master valve 24, an ECU 23, and a rocker switch 16;

[0060] The ECU is connected to a conversion relay 22 through a brake light switch 3;

[0061] The conversion relay 22 is connected to a pneumatic signal switch; the pneumatic signal switch is arranged at the air source interface position of the secondary brake master valve 24, and when the secondary brake master valve 24 connects to the air source, the pneumatic signal switch closes;

[0062] The ECU is connected to a brake light through a controller B 20;

[0063] The brake light switch 3 is connected to the control end of the main brake master valve 4;

[0064] The brake light switch 3 is connected to the secondary brake master valve 24 through the conversion relay 22 and the pneumatic signal switch in sequence;

[0065] The main brake master valve 4 is connected to the secondary brake master valve 24 through a two-way three-way solenoid valve;

[0066] The control ends of the two-way three-way solenoid valve are respectively connected to the pneumatic signal switch and the rocker switch 16;

[0067] The two-position three-way solenoid valve includes a first two-position three-way solenoid valve 10 connected to the first air source interface of the secondary brake master valve 24 and a second two-position three-way solenoid valve 21 connected to the second air source interface of the secondary brake master valve.

[0068] The system further includes a front axle service air reservoir 1 and a rear axle service air reservoir 2.

[0069] The front axle service air reservoir 1 is respectively connected to the first air source interface of the main brake master valve 4 and the first air source interface of the secondary brake master valve 24.

[0070] The rear axle service air reservoir 2 is respectively connected to the second air source interface of the main brake master valve 4 and the second air source interface of the secondary brake master valve 24.

[0071] The first air source interface of the main brake master valve 4 is respectively connected to the first two-position three-way solenoid valve 10 and the second two-position three-way solenoid valve 21 through a first double-check non-return valve 11.

[0072] The second air source interface of the main brake master valve 4 is respectively connected to the first two-position three-way solenoid valve 10 and the second two-position three-way solenoid valve 21 through a second double-check non-return valve 12.

[0073] The first double-check non-return valve 11 is connected to an EBS front axle module 9.

[0074] The EBS front axle module 9 is connected to a first front axle brake chamber 5 through a first front axle ABS solenoid valve 7.

[0075] The EBS front axle module 9 is connected to a second front axle brake chamber 6 through a second front axle ABS solenoid valve 8.

[0076] The second double-check non-return valve 12 is connected to an EBS rear axle module 13.

[0077] The EBS rear axle module 13 is connected to a first rear axle brake chamber 14 and a second rear axle brake chamber 15.

[0078] As a preference of the technical solution of the present invention, the air pressure signal switch is connected to the secondary brake master valve through a three-way connection.

[0079] The system further includes a combined instrument 17 respectively connected to a controller B20 and an ECU, which is used to receive the message sent by the ECU, display the ECU fault on the instrument, drive the brake lamp to light up after the controller B detects that the brake lamp circuit is normal, and output a brake diagram on the instrument.

[0080] When the main brake pedal is depressed and the secondary brake pedal is not depressed, the main brake master valve 4 opens, and compressed air flows from the front axle service air reservoir 1 and the rear axle service air reservoir 2 through the main brake master valve 4 to the front axle two-way check valve 11 and the rear axle two-way check valve 12. At this time, since the secondary brake pedal is not depressed, the secondary brake master valve 24 is closed. Since the front axle two-way check valve 11 and the rear axle two-way check valve 12 respectively compare the air pressure of the incoming gas, the air path with the higher air pressure will be output through the output port and enter the EBS front axle module 9 and the EBS rear axle module 13. After passing through the EBS front axle module 9 and the EBS rear axle module 13, it is respectively controlled to enter the first front axle brake chamber 5, the second front axle brake chamber 6, the first rear axle brake chamber 14 and the second rear axle brake chamber 15 to perform the braking action. When the main brake pedal is depressed, the elastic hoop fixed to the main brake pedal moves with the main brake pedal. When the elastic hoop moves to a distance less than 4.5 mm from the brake light switch, the contacts 1-3 of the brake light switch are closed, and the contacts 1-4 are opened. The electrical signal output by the ECU returns to the ECU through the closed contacts 1-3 of the brake light switch. Since the secondary brake function is not working, the air pressure signal switch is open, the conversion relay 22 does not work, the contacts 3-4 of the conversion relay are closed, and the secondary brake pin of the ECU is floating.

[0081] During main brake application, the brake light switch inputs the main and secondary brake signals to the ECU through the conversion relay. The ECU judges the brake signal. When the judgment is unreasonable, the ECU sends a fault message and the instrument displays an ECU fault. When the judgment is reasonable, the ECU cuts off the fuel supply and limits the torque, and sends a brake message. Controller B receives the brake message and drives to detect whether the main / trailer brake lights are faulty. If there is no problem, (if there is a problem, controller B sends a fault status message to the instrument and the instrument reports a controller B fault) controller B drives the main / trailer brake lights to light up, and at the same time sends a brake light status message to the instrument, and the brake light indicator on the instrument lights up.

[0082] When the secondary brake pedal is depressed and the primary brake pedal is not depressed, the secondary brake master valve opens, and compressed air passes from the front axle service air reservoir 1 and the rear axle service air reservoir 2 through the primary brake master valve 4 to the front axle two-way check valve 11 and the rear axle two-way check valve 12. Since the front axle two-way check valve 11 and the rear axle two-way check valve 12 respectively compare the air pressure of the incoming gas, the air circuit with the higher air pressure will be output through the outlet and enter the EBS front axle module 9 and the EBS rear axle module 13. After being controlled by the EBS front axle module 9 and the EBS rear axle module 13, it enters the first front axle brake chamber 5, the second front axle brake chamber 6, the first rear axle brake chamber 14 and the second rear axle brake chamber 15 respectively to perform the braking action. Since the secondary brake master valve is open and the air pressure is greater than 0.05 MPa, the air pressure signal switch installed on the tee of the secondary brake master valve air source interface closes, and the contact 3-5 of the conversion relay 22 closes. Since the primary brake pedal is not depressed and the primary brake function is not working, the contact 1-4 of the brake light switch closes. The controller electrical signal passes through the brake light switch 1-4 to the conversion relay 3-5 and then returns to the controller primary brake switch pin. At this time, the conversion relay 3-4 is disconnected, so the secondary brake switch pin is floating.

[0083] During secondary braking, when the air pressure signal switch closes and the conversion relay operates, the ECU primary brake switch signal is pulled low. The engine power output passes through the brake light switch and the conversion relay and then inputs the brake signal to the ECU secondary brake switch. The ECU judges the brake signal. When the judgment is unreasonable, the ECU sends a fault message, and the instrument displays an ECU fault. When the judgment is reasonable, the ECU cuts off the fuel supply and limits the torque, and sends a braking message. Controller B receives the braking message and drives to detect whether the main / hanger brake lights are faulty. If there is no problem, (if there is a problem, controller B sends a fault status message to the instrument, and the instrument reports a controller B fault) controller B drives the main / hanger brake lights to light up, and at the same time sends a brake light status message to the instrument, and the instrument brake light indicator lights up.

[0084] When the main brake pedal and the auxiliary brake pedal are depressed simultaneously, the main brake master valve 4 and the auxiliary brake master valve 24 work simultaneously. Compressed air passes from the front axle service air reservoir 1 and the rear axle service air reservoir 2 through the main brake master valve 4 to the front axle two-way check valve 11 and the rear axle two-way check valve 12. Since the front axle two-way check valve 11 and the rear axle two-way check valve 12 respectively compare the air pressure of the incoming gas, the air circuit with the higher air pressure will be output through the output port and enter the EBS front axle module 9 and the EBS rear axle module 13. After being controlled by the EBS front axle module 9 and the EBS rear axle module 13, it enters the first front axle brake chamber 5, the second front axle brake chamber 6, the first rear axle brake chamber 14 and the second rear axle brake chamber 15 respectively to perform the braking action. When the main brake pedal is depressed, the elastic hoop fixed to the main brake pedal moves with the main brake pedal. When the elastic hoop moves to a distance less than 4.5 mm from the brake light switch, the contacts 1-3 of the brake light switch are closed, and the contacts 1-4 are disconnected and then closed. The electrical signal output by the controller returns to the main brake switch pin of the controller through the contacts 1-3 of the brake light switch. Since the auxiliary brake master valve is opened and the air pressure is greater than 0.05 MPa, the air pressure signal switch installed on the tee of the air source interface of the auxiliary brake master valve is closed, the conversion relay 3-5 is closed, and 3-4 is disconnected. At this time, the electrical signal output by the controller returns to the main brake switch pin of the controller through the brake light switch 1-3. Since the conversion relay 3-4 is disconnected, the auxiliary brake switch pin of the controller is floating.

[0085] When the main and auxiliary brakes act simultaneously, the brake light switch inputs the main brake signal output by the engine power supply to the ECU through the conversion relay. At this time, the air pressure signal switch is closed, and the conversion relay operates. The auxiliary brake signal inputs a low-level signal to the ECU through the brake light switch and the conversion relay. The ECU judges the brake signal. When the judgment is unreasonable, the ECU sends a fault message, and the instrument displays an ECU fault. When the judgment is reasonable, the ECU cuts off the fuel supply and limits the torque, and sends a brake message. The controller B receives the brake message and drives to detect whether the main / trailer brake lights are faulty. If there is no problem, (if there is a problem, the controller B sends a fault status message to the instrument, and the instrument reports a controller B fault) the controller B drives the main / trailer brake lights to light up, and at the same time sends a brake light status message to the instrument, and the brake light indicator of the instrument lights up. It should be noted that the controller in the embodiments and the drawings of the present application refers to the ECU. Here, the brake lights include the main vehicle brake lights and the trailer brake lights.

[0086] The two-way three-way valve is in the normally open state. When the rocker switch is pressed, the two-way three-way valve closes. At this time, the air circuit between the auxiliary brake master valve and the two-way check valve is disconnected, and the auxiliary brake function fails.

[0087] The air pressure signal switch is connected to the air source interface position of the secondary brake master valve through a tee. When the secondary brake is working, the air pressure signal switch closes, the normally closed switch of the conversion relay disconnects, and the normally open switch closes. The normally open switch loop connected by the conversion relay conducts with the brake light switch of the primary brake, and outputs a signal to the ECU primary brake switch pin; two two-way three-way valves are added to the secondary brake air circuit to control the on-off of the front and rear axle air circuits of the secondary brake. The two two-way three-way valves are connected in parallel and are normally open, and are controlled by a rocker switch. When the rocker switch is turned on, the two-way three-way solenoid valve closes and the secondary brake function is turned off; when the primary and secondary brakes work simultaneously, the normally closed contact of the brake light switch disconnects, the normally open contact conducts, the air pressure signal switch closes, the normally closed switch of the conversion relay disconnects, and the normally open switch conducts. The ECU primary brake switch pin is at a high level, and the ECU secondary brake switch pin is floating. The logic judgment is normal and a brake message can be output; when the secondary brake is working, the ECU primary brake switch pin is at a high level, and the ECU secondary brake switch pin is floating. The ECU judges that the brake function is normal and outputs a brake message to controller B and the instrument. After controller B detects that the brake light circuit is normal, it drives the brake light to light up, and the instrument outputs a brake diagram.

[0088] The embodiment of the present invention also provides a main and secondary brake control method for a heavy-duty vehicle, including the following steps:

[0089] When the secondary brake pedal is depressed and the primary brake pedal is not depressed, the secondary brake master valve opens, and compressed air passes from the front / rear axle service air storage tank through the secondary brake master valve to the front / rear axle two-way one-way valve. According to the different air pressures, the spool of the front / rear axle two-way one-way valve moves, so that the air circuit with a higher air pressure is output through the output port of the front / rear axle two-way one-way valve and enters the EBS front axle module and the EBS rear axle module, and then enters the front axle brake air chamber and the rear axle brake air chamber respectively through the control of the EBS front axle module and the EBS rear axle module to perform braking actions;

[0090] When the air pressure at the air source interface is greater than the set threshold after the secondary brake master valve is opened, the air pressure signal switch installed on the tee of the air source interface closes, the conversion relay operates, the normally closed switch disconnects, and the normally open switch closes. Since the primary brake pedal is not depressed, the brake light switch is in the normally closed state at this time. The ECU electrical signal passes through the normally closed switch of the brake light switch to the normally open switch closed by the conversion relay and then returns to the ECU primary brake switch pin. At this time, the normally closed switch of the conversion relay disconnects, so the secondary brake switch pin is floating;

[0091] After the secondary brake master valve is opened, the air pressure signal switch closes. After the conversion relay operates, the ECU primary brake switch signal is pulled low. The engine power output passes through the brake light switch and the conversion relay and then inputs the brake signal to the ECU secondary brake switch, and the ECU judges the brake signal;

[0092] When the judgment is unreasonable, the ECU sends a fault message and displays the ECU fault through the instrument;

[0093] When the judgment is reasonable, the ECU cuts off fuel supply and limits torque, and sends a braking message. Controller B receives the braking message and drives to detect whether the brake lamp is faulty. If there is no fault, Controller B drives the brake lamp to light up, and at the same time sends a brake lamp status message to the instrument, and the instrument brake lamp indicator lights up; if there is a fault, Controller B sends a fault status message to the instrument, and the instrument reports a fault of Controller B.

[0094] When the main brake pedal is depressed and the auxiliary brake pedal is not depressed, the main brake master valve opens, and compressed air passes from the front / rear axle service air reservoirs through the main brake master valve to the front / rear axle double-check non-return valve. According to the different air pressures, the spool of the front / rear axle double-check non-return valve moves, allowing the air circuit with higher air pressure to pass through the output port of the front / rear axle double-check non-return valve and enter the EBS front axle module and EBS rear axle module. After being controlled by the EBS front axle module and EBS rear axle module, it enters the front axle brake chamber and rear axle brake chamber respectively to perform braking actions;

[0095] When the main brake pedal is depressed, the elastic hoop fixed to the main brake pedal moves with the main brake pedal. When the elastic hoop moves to a distance less than the first threshold from the brake lamp switch, the normally open contact of the brake lamp switch closes, and the normally closed contact of the brake lamp switch opens. The electrical signal output by the ECU returns to the ECU through the closed normally open contact of the brake lamp switch. At this time, the air pressure signal switch is disconnected, the conversion relay does not work, the normally closed switch of the conversion relay is in the closed state, and the ECU auxiliary brake pin is floating;

[0096] When the main brake master valve opens, the brake lamp switch inputs the main and auxiliary brake signals to the ECU through the conversion relay, and the ECU makes a braking signal judgment;

[0097] When the judgment is unreasonable, the ECU sends a fault message, and the instrument displays an ECU fault;

[0098] When the judgment is reasonable, the ECU cuts off fuel supply and limits torque, and sends a braking message. Controller B receives the braking message and drives to detect whether the brake lamp is faulty. If there is no fault, Controller B drives the brake lamp to light up, and at the same time sends a brake lamp status message to the instrument, and the instrument brake lamp indicator lights up; if there is a fault, Controller B sends a fault status message to the instrument, and the instrument reports a fault of Controller B.

[0099] When the main brake pedal and the auxiliary brake pedal are depressed simultaneously, the main brake master valve and the auxiliary brake master valve open simultaneously. Compressed air flows from the front / rear axle service air reservoirs through the main brake master valve and the auxiliary brake master valve to the front / rear axle double-check non-return valves. The compressed air in the main brake air circuit and the compressed air in the auxiliary brake air circuit are compared in terms of air pressure at the position of the front / rear axle double-check non-return valves. The brake air circuit with higher air pressure enters the EBS front axle module and the EBS rear axle module through the front / rear axle double-check non-return valves. After being controlled by the EBS front axle module, it enters the front axle brake air chamber through the front axle ABS solenoid valve for braking. After being controlled by the EBS rear axle module, it enters the rear axle brake air chamber for braking;

[0100] When the main brake pedal is depressed, the elastic hoop fixed to the main brake pedal moves with the main brake pedal; when the elastic hoop moves to a distance less than the first threshold from the brake light switch, the normally open contact of the brake light switch closes, and the normally closed contact of the brake light switch opens. The electrical signal output by the ECU returns to the main brake switch pin of the ECU through the normally open contact closed by the brake light switch; since the auxiliary brake master valve is open, the air pressure signal switch installed on the tee of the air source interface of the auxiliary brake master valve closes, and the conversion relay operates to close the normally open switch and open the normally closed switch. At this time, the electrical signal output by the ECU returns to the main brake switch pin of the ECU through the normally open contact closed by the brake light switch. Since the normally closed switch of the conversion relay is open, the auxiliary brake switch pin of the ECU is floating.

[0101] When the main brake master valve and the auxiliary brake master valve open simultaneously, the brake light switch inputs the main brake signal output by the engine power supply to the ECU through the conversion relay. At this time, the air pressure signal switch closes, and the conversion relay operates. The auxiliary brake signal inputs a low-level signal to the ECU through the brake light switch and the conversion relay, and the ECU judges the brake signal;

[0102] When the judgment is unreasonable, the ECU sends a fault message, and the instrument displays an ECU fault;

[0103] When the judgment is reasonable, the ECU cuts off the fuel supply and limits the torque, and sends a brake message. Controller B receives the brake message and drives to detect whether the brake light is faulty. If there is no fault, Controller B drives the brake light to light up and sends a brake light status message to the instrument, and the instrument brake light indicator lights up; if there is a fault, Controller B sends a fault status message to the instrument, and the instrument reports a fault of Controller B.

[0104] Although the present invention has been described in detail by referring to the accompanying drawings and in conjunction with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, those of ordinary skill in the art can make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions should all fall within the scope of the present invention. / Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the said claims.

Claims

1. A primary and secondary braking control system for a heavy-duty vehicle, characterized in that, It includes a main brake master valve, a secondary brake master valve, an ECU, a rocker switch, a first double-check valve and a second double-check valve; The ECU is connected to a conversion relay through a brake light switch; the conversion relay is connected to a pneumatic signal switch; the pneumatic signal switch is arranged at the air source interface position of the secondary brake master valve, and when the secondary brake master valve connects to the air source, the pneumatic signal switch closes; the ECU is connected to a brake light through controller B; The brake light switch is connected to the control end of the main brake master valve; the brake light switch is sequentially connected to the secondary brake master valve through the conversion relay and the pneumatic signal switch; The main brake master valve is connected to the secondary brake master valve through a two-position three-way solenoid valve; the control ends of the two-position three-way solenoid valve are respectively connected to the pneumatic signal switch and the rocker switch; The first double-check valve is respectively connected to the main brake master valve and the secondary brake master valve, and the second double-check valve is respectively connected to the main brake master valve and the secondary brake master valve. The first double-check valve or the second double-check valve compares the air pressures of the main brake master valve and the secondary brake master valve respectively, and leads the side with higher air pressure to the front axle or the rear axle for braking.

2. The master-slave braking control system for heavy-duty vehicles according to claim 1, characterized in that The two-position three-way solenoid valve includes a first two-position three-way solenoid valve connected to the first air source interface of the secondary brake master valve and a second two-position three-way solenoid valve connected to the second air source interface of the secondary brake master valve; The system further includes a front axle service air reservoir and a rear axle service air reservoir; The front axle service air reservoir is respectively connected to the first air source interface of the main brake master valve and the first air source interface of the secondary brake master valve; The rear axle service air reservoir is respectively connected to the second air source interface of the main brake master valve and the second air source interface of the secondary brake master valve; The first air source interface of the main brake master valve is respectively connected to the first two-position three-way solenoid valve and the second two-position three-way solenoid valve through the first double-check valve; The second air source interface of the main brake master valve is respectively connected to the first two-position three-way solenoid valve and the second two-position three-way solenoid valve through the second double-check valve.

3. The main and auxiliary braking control system for heavy-duty vehicles according to claim 2, characterized in that, The first double-check valve is connected to an EBS front axle module; The EBS front axle module is connected to a first front axle brake chamber through a first front axle ABS solenoid valve; The EBS front axle module is connected to a second front axle brake chamber through a second front axle ABS solenoid valve.

4. The main and auxiliary braking control system for heavy-duty vehicles according to claim 3, characterized in that, The second double-check valve is connected to an EBS rear axle module; The EBS rear axle module is connected to a first rear axle brake chamber and a second rear axle brake chamber.

5. The main and auxiliary braking control system for heavy-duty vehicles according to claim 4, characterized in that, The pneumatic signal switch is connected to the secondary brake master valve through a three-way pipe.

6. The main and auxiliary braking control system for heavy-duty vehicles according to claim 5, characterized in that, The system further includes a combined instrument respectively connected to controller B and the ECU, which is used to receive the message sent by the ECU, display the ECU fault on the instrument, drive the brake light to light up after controller B detects that the brake light circuit is normal, and the instrument outputs a brake diagram.

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