A headlight function fault diagnosis system and method thereof

Abstract

The present invention provides a headlamp function fault diagnosis system and method thereof, which connect a driving unit and a latching unit to stabilize a diagnostic signal, and use a decoding unit and a duty cycle generating unit to implement inputting a corresponding duty cycle according to the stable diagnostic signal. The present invention does not require a microcontroller to calculate and output the duty cycle, and does not need to invest in complicated software design, greatly reducing the product cost.

Description

Technical Field

[0001] The present invention relates to the field of automotive parts, and particularly to a headlight function fault diagnosis system and method thereof. Background Art

[0002] In the field of vehicles, due to the requirements of functional safety, regulations for many functions (such as the turn signal and brake light functions of the taillights) stipulate that diagnostic signals need to be output to the body controller. Under this requirement, in order to simplify the system and save wiring harnesses, vehicles on the market usually use a single wiring harness to transmit diagnostic signals of different functions, and represent various different states of various functions by outputting PWM signals with different duty cycles. For example, a 20% duty cycle represents that the brake light and turn signal are working properly, 40% represents that the brake light fails, 60% represents that the turn signal fails, and 80% represents that both the brake light and turn signal fail. Currently, this kind of diagnostic output with different duty cycles usually needs to be implemented by a single-chip microcomputer (microcomputer). This requires a large amount of software design resources, and the development cycle and test cost will also increase significantly. Summary of the Invention

[0003] In order to overcome the above technical defects, an object of the present invention is to provide a headlight function fault diagnosis system and method thereof, which connect a driving unit and a latching unit to stabilize the diagnostic signal, and then use a decoding unit and a duty cycle generating unit to implement inputting corresponding duty cycles according to the stable diagnostic signal. The present invention does not require a single-chip microcomputer to calculate and output the duty cycle, and does not require complicated software design, greatly reducing the product cost.

[0004] The present invention discloses a headlight function fault diagnosis system on the one hand, which includes at least one driving unit, at least one latching unit connected to the driving unit, a decoding unit connected to the latching unit, a duty cycle generating unit connected to the decoding unit, and an output unit.

[0005] Preferably, in the above headlight function fault diagnosis system, the latching unit includes a first NPN transistor, a second NPN transistor, and a PNP transistor. The bases of the first NPN transistor and the second NPN transistor are both connected to the collector of the PNP transistor. The emitter of the first NPN transistor is grounded, and the collector is connected to the base of the PNP transistor. The emitter of the second NPN transistor is also grounded, and the collector is connected to the emitter of the PNP transistor. The collector of the PNP transistor is grounded. A power supply and a capacitor are connected between the base and the emitter of the PNP transistor. The capacitor is connected in parallel with the power supply, and the power supply is also connected to the collector of the first NPN transistor.

[0006] Preferably, in the above headlight function fault diagnosis system, the power supply is connected to the vehicle's BCM.

[0007] Preferably, in the above headlight function fault diagnosis system, the decoding unit includes an input port, an output port, and a decoding module. The number of input ports is the same as the number of driving units, and the decoding module is configured to generate a control signal according to the second diagnostic signal and the input port information of the second diagnostic signal.

[0008] Preferably, in the above headlight function fault diagnosis system, the duty ratio generation unit includes a data selector, a PWM signal generator, and a duty ratio generation circuit. The data selector is connected to the decoding unit, the duty ratio generation circuit is connected to the data selector, and the PWM signal generator is connected to the duty ratio generation circuit.

[0009] Preferably, in the above headlight function fault diagnosis system, the duty ratio generation unit includes a PWM signal generation circuit and a duty ratio selection circuit. The duty ratio selection circuit is connected to the decoding unit, and the PWM signal generator is connected to the duty ratio selection circuit.

[0010] Preferably, in the above headlight function fault diagnosis system, the output unit includes an OC gate, a high-side drive, or a low-side drive circuit.

[0011] On the other hand, the present invention discloses a method for diagnosing headlight function faults, which includes the following steps: the driving unit sends a first diagnostic signal to the latching unit; the latching unit processes the first diagnostic signal to form a stable second diagnostic signal and sends it to the decoding unit; the decoding unit generates a control signal according to the second diagnostic signal and sends it to the duty ratio generation unit; the duty ratio generation unit generates a corresponding duty ratio signal according to the control signal and sends it to the output unit; the output circuit sends the duty ratio signal to the vehicle's BCM.

[0012] Preferably, in the above method for diagnosing headlight function faults, the step of the latching unit processing the first diagnostic signal to form a stable second diagnostic signal includes: the latching unit is a latching circuit, the first diagnostic signal is an electrical signal, when the first diagnostic signal received by the latching circuit is at a low level, the latching function of the latching circuit is awakened, the latching circuit reduces the level value of the first diagnostic signal, so that the second diagnostic signal output from the latching circuit is at a low level, and after the latching function of the latching circuit is awakened, when the latching unit receives the first diagnostic signal at a high level, it also outputs a low level as the second diagnostic signal.

[0013] Preferably, in the above headlight function fault diagnosis method, the power supply is connected to the vehicle's BCM, and the power supply receives the start signal from the BCM, supplies power to the latch circuit, and starts the latch circuit.

[0014] Preferably, in the above headlight function fault diagnosis method, the step in which the decoding unit generates a control signal according to the second diagnosis signal includes: the decoding unit determines whether a headlight function fault has occurred according to the second diagnosis signal, and according to the port information of the input port of the second diagnosis signal, analyzes the headlight function information of the headlight function fault that has occurred, and generates a control signal according to the port information and the headlight function information.

[0015] Preferably, in the above headlight function fault diagnosis method, the step in which the duty ratio generation unit generates a corresponding duty ratio signal according to the control signal and sends it to the output unit includes: the duty ratio generation unit includes a data selector, a PWM signal generator, and a duty ratio generation circuit. The duty ratio generation circuit receives the PWM signal sent by the PWM signal generator, generates at least one duty ratio signal. Different duty ratio signals are input into different lines of the data selector. The data selector conducts the line associated with the control signal according to the control signal, and sends the duty ratio signal to the output unit through the line.

[0016] Preferably, in the above headlight function fault diagnosis method, the step in which the duty ratio generation unit generates a corresponding duty ratio signal according to the control signal and sends it to the output unit includes: the duty ratio generation unit includes a PWM signal generation circuit and a duty ratio selection circuit. The PWM signal generation circuit is connected to different duty ratio circuits. The duty ratio generation unit connects different duty ratio circuits according to different control signals, and outputs different duty ratio signals to the output unit.

[0017] Preferably, in the above headlight function fault diagnosis method, according to the requirements of the vehicle BCM, the output unit is set as an open collector gate, a high-side driver, or a low-side driver.

[0018] After adopting the above technical solution, compared with the prior art, it has the following beneficial effects:

[0019] 1. It avoids the dependence of headlight function fault diagnosis on software development in the single-chip microcomputer;

[0020] 2. It can flexibly configure the corresponding number of duty ratios and control signals according to the number of headlight functions, and provides an effective and flexible headlight function fault diagnosis system and method. Description of the Drawings

[0021] Figure 1Schematic diagram of a headlight function fault diagnosis system according to a preferred embodiment of the present invention;

[0022] Figure 2 Schematic diagram of a latch circuit according to a preferred embodiment of the present invention;

[0023] Figure 3 Flowchart of a headlight function fault diagnosis method according to a preferred embodiment of the present invention. Detailed implementation manners

[0024] The advantages of the present invention will be further elaborated below in conjunction with the accompanying drawings and specific embodiments.

[0025] Refer to Figure 1 , which is a schematic diagram of the mechanism of a headlight function fault diagnosis system according to a preferred embodiment of the present invention. It can be seen from the figure that the headlight function fault diagnosis system provided in this embodiment includes the following units:

[0026] - Driving unit

[0027] From Figure 1 it can be seen that the headlight function fault diagnosis system provided in this embodiment includes at least one driving unit. This driving unit can be the driving unit of the headlight function itself and can realize controlling the lighting, functional flashing, etc. of the headlight function. Therefore, the number of driving units corresponds to the number of headlight functions. There are as many driving units as there are headlight functions participating in this headlight fault diagnosis system. In this embodiment, the driving unit is configured to be able to detect the state of the headlight function, generate and send out diagnostic signals in real time, and moreover, the specific headlight function corresponding to each diagnostic signal can be distinguished according to the driving unit that sends the diagnostic signal. Preferably, the driving unit can be a driving circuit, and the diagnostic signal is an electrical signal of high level or low level.

[0028] - Latching unit

[0029] In practice, the fault state of the headlight function is often unstable, and the headlight function may sometimes work properly and sometimes not, resulting in unstable diagnostic signals. However, at this time, the headlight function should be recognized as a fault state. Therefore, in this embodiment, the driving unit is connected to the latching unit, so that the diagnostic signal output by the driving unit is input into the latching unit. The latching unit processes the diagnostic signal. When the diagnostic signal continuously indicates that the headlight function is normal, the diagnostic signal output by the latching unit is also a diagnostic signal indicating that the headlight function is normal. Once a diagnostic signal indicating a headlight function fault is input into the latching unit, the diagnostic signals output from the latching unit are all diagnostic signals indicating a headlight function fault. That is, when the diagnostic signal indicating a headlight function fault is first input into the latching unit, the latching unit is activated, so that the current diagnostic signal and the subsequent diagnostic signals input into the latching unit are all output as diagnostic signals indicating a headlight function fault, thereby realizing the stable output of the diagnostic signal for the headlight function.

[0030] Preferably, when the diagnostic signal is an electrical signal, and a high level indicates that the headlight function is normal and a low level indicates that the headlight function is faulty, then when a high level is input into the latching unit, the output from the latching unit is still a high level. When a low level is input into the latching unit, the latching unit is activated, and not only is the output from the latching unit a low level this time, but the subsequent high levels input into the latching unit are also output as low levels.

[0031] Preferably, the number of latching units corresponds to the number of driving units, that is, each driving unit is connected to a latching unit. Therefore, it can be ensured that the diagnostic signals for each headlight function can be stably output.

[0032] - Decoding unit

[0033] The decoding unit in this embodiment is connected to the latching unit, can receive the diagnostic signal processed by the latching unit, and parse the diagnostic signal. According to the parsed diagnostic signal and the rules formulated based on the subsequent duty cycle output requirements, corresponding control signals are generated.

[0034] - Duty cycle generation unit

[0035] The duty cycle generation unit in this embodiment is connected to the decoding unit, can receive the control signal sent by the decoding unit, and generate corresponding duty cycle signals according to the control signal and the rules formulated based on the subsequent duty cycle output requirements. Moreover, the generated duty cycle signals characterize the current state of the headlight function and can be received by the relevant processing units of the vehicle.

[0036] - Output unit

[0037] The output unit in this embodiment can be configured according to the relevant requirements of a vehicle-related processing unit for receiving and processing headlight function diagnosis information. For example, it can be an open-collector gate, a high-side driver, or a low-side driver. Thus, the output unit here can receive the duty cycle signal generated by the above duty cycle generation unit and output it to the vehicle-related processing unit for subsequent processing.

[0038] Based on the above design, in this embodiment, a diagnosis system with simple design and operation is implemented to monitor the status of the headlight function in real time. Once a fault occurs in the headlight function, it can accurately report the fault to the vehicle-related processing unit. The diagnosis system can adapt to the diagnosis requirements of the headlight functions of different vehicles without developing software for a single-chip microcomputer by configuring different numbers of latch units, decoder units, and the relevant signal generation rules of the duty cycle generation unit, reducing the software development cycle and cost, and ultimately reducing the manufacturing cost of the diagnosis system.

[0039] Based on the above embodiment, in another preferred embodiment of the present invention, the latch unit can be a latch circuit. Preferably, it can be a latch circuit composed of an NPN transistor and a PNP transistor. Specifically, as Figure 2 shown, it includes a first NPN transistor (Q1), a second NPN transistor (Q2), and a PNP transistor (Q3). The bases of the first NPN transistor (Q1) and the second NPN transistor (Q2) are both connected to the collector of the PNP transistor (Q3). The emitter of the first NPN transistor (Q1) is grounded, and the collector is connected to the base of the PNP transistor (Q3). The emitter of the second NPN transistor (Q2) is also grounded, and the collector is connected to the emitter of the PNP transistor (Q3). The collector of the PNP transistor (Q3) is grounded. A power supply and a capacitor (C1) are connected between the base and the emitter of the PNP transistor (Q3). The capacitor (C1) is in parallel with the power supply, and the power supply is simultaneously connected to the collector of the first NPN transistor (Q1). At the same time, based on the above circuit design, those skilled in the art can also add different protection resistors at different positions in the circuit of the above latch circuit according to actual needs to ensure the safe operation of the above latch circuit, which is easily obtained by those skilled in the art.

[0040] Thus, based on the latch circuit designed above, when the first diagnostic signal representing the normal high level of the headlight function is input into the latch circuit, Q3 is not turned on, and the output of the latch circuit is still the high level as the second diagnostic signal, indicating that the headlight function is normal; while when the first diagnostic signal representing the faulty low level of the headlight function is input into the latch circuit, Q3 is turned on, and the second diagnostic signal input into the diagnostic circuit is the low level. Moreover, subsequently, even if the first diagnostic signal input into the latch circuit is the high level, it will be pulled down by the latch circuit, so as to output the second diagnostic signal of the low level. Thus, the technical effect of a stable diagnostic signal is achieved.

[0041] In addition, in a preferred solution based on the above embodiment, the power supply in the above circuit is a power supply connected to the vehicle body control system of the vehicle. Thus, the on-off of the power supply can be controlled by the vehicle body control system, and thus, the operation of the latch circuit can be controlled. For example, the power supply can be a power supply controlled by the vehicle start signal. Then, when the vehicle starts, the latch circuit operates, and the headlight function diagnosis system monitors the state of the headlight function in real time. After receiving the diagnostic signal representing the headlight function failure for the first time, it stably outputs the diagnostic signal representing the headlight function failure. While when the vehicle stops running, the latch circuit also stops running. When the vehicle starts again, the latch circuit resets to the original state, and its latch function is activated only when the diagnostic signal representing the headlight function failure is received again.

[0042] Based on the above embodiment, in another preferred embodiment of the present invention, the decoding unit may include an input port, an output port, and a decoding module. The number of input ports therein is the same as the number of driving units, and the decoding module is configured to generate a control signal according to the second diagnostic signal and the input port information of the second diagnostic signal. Thus, the decoding unit can use the input port to mark the headlight function corresponding to the diagnostic signal input from the input port. Thus, the decoding module in the decoding unit can combine the diagnostic signal and the information of the headlight function corresponding to the diagnostic signal, and generate a corresponding control signal according to the preset rules. Preferably, the decoding module in the decoding unit can be a decoding chip or a decoding circuit.

[0043] In another preferred embodiment of the present invention based on the above embodiments, the duty cycle generation unit may include a data selector, a PWM signal generator, and a duty cycle generation circuit. The data selector therein may receive the control signal generated and sent by the above decoding unit, and also receive the duty cycles generated and sent by the duty cycle generation circuit, and select the corresponding duty cycle from these duty cycles according to the control signal and send it to the output unit. The working principle of the duty cycle generation circuit therein is that the PWM signal generator generates a PWM wave and sends it to the duty cycle generation circuit, and the duty cycle generation circuit generates one or more duty cycles based on the received PWM wave according to a preset rule. For example, in a headlight function fault diagnosis system based on two headlight functions, 4 duty cycle signals are set: a 20% duty cycle can be used to indicate that the brake light and the turn signal are working properly; a 40% duty cycle can be used to indicate that the brake light fails; a 60% duty cycle can be used to indicate that the turn signal fails; an 80% duty cycle can be used to indicate that both the brake light and the turn signal fail.

[0044] In another preferred embodiment of the present invention based on the above embodiments, the duty cycle generation unit includes a PWM signal generation circuit and a duty cycle selection circuit. Different from the above embodiments, in this embodiment, the duty cycle generation circuit and the data selector are combined into one duty cycle selection circuit. The duty cycle selection circuit therein configures a corresponding number of duty cycle generation circuits according to the preset number requirement of duty cycles, that is, each duty cycle generation circuit can generate a specific duty cycle value. Thus, without additionally setting a data selector, the duty cycle generation unit can directly control the conduction of the corresponding duty cycle generation circuit according to the control signal generated by the decoding unit, achieving the effect of generating the corresponding duty cycle according to the control signal.

[0045] It can be seen from the above embodiments that the headlight function fault diagnosis system provided by the present invention avoids the dependence on software development in the single-chip microcomputer for headlight function fault diagnosis; it can flexibly configure the corresponding number of duty cycles and control signals according to the number of headlight functions, providing an effective and flexible headlight function fault diagnosis system and method.

[0046] As Figure 3 shown, on the other hand, the present invention also lies in providing a headlight function fault diagnosis method, which can be applied to the headlight function fault diagnosis system described in the above embodiments. It specifically includes the following steps:

[0047] - The driving unit sends a first diagnosis signal to the latching unit;

[0048] - The latching unit processes the first diagnosis signal to form a stable second diagnosis signal and sends it to the decoding unit;

[0049] - The decoding unit generates a control signal according to the second diagnostic signal and sends it to the duty cycle generation unit;

[0050] - The duty cycle generation unit generates a corresponding duty cycle signal according to the control signal and sends it to the output unit;

[0051] - The output circuit sends the duty cycle signal to the vehicle's BCM.

[0052] Preferably, the driving unit, the latching unit, the decoding unit, the duty cycle generation unit, and the output unit in this embodiment can all be configured as described in the embodiments of the above-mentioned headlight function fault diagnosis system.

[0053] Based on the above embodiment, in another preferred embodiment of the present invention, the latching unit is a latching circuit, and the first diagnostic signal is an electrical signal. Then, the steps for the latching unit to process the first diagnostic signal to form a stable second diagnostic signal include:

[0054] - When the first diagnostic signal received by the latching circuit is at a low level, the latching function of the latching circuit is awakened, and the latching circuit reduces the level value of the first diagnostic signal, so that the second diagnostic signal output from the latching circuit is at a low level;

[0055] - After the latching function of the latching circuit is awakened, when the latching unit receives the first diagnostic signal at a high level, it also outputs a low level as the second diagnostic signal.

[0056] Based on the above embodiment, in another preferred embodiment of the present invention, the power supply is connected to the vehicle's BCM, the power supply receives the start signal from the BCM, supplies power to the latching circuit, and starts the latching circuit.

[0057] Based on the above embodiment, in another preferred embodiment of the present invention, the steps for the decoding unit to generate a control signal according to the second diagnostic signal include:

[0058] - The decoding unit determines whether a headlight function fault has occurred according to the second diagnostic signal;

[0059] And

[0060] - According to the port information of the input port of the second diagnostic signal, parse the headlight function information of the headlight function fault that has occurred, and generate a control signal according to the port information and the headlight function information.

[0061] In another preferred embodiment of the present invention, the steps for the duty cycle generation unit to generate a corresponding duty cycle signal according to the control signal and send it to the output unit include:

[0062] - The duty cycle generation unit includes a data selector, a PWM signal generator, and a duty cycle generation circuit;

[0063] - The duty cycle generation circuit receives the PWM signal sent by the PWM signal generator and generates at least one duty cycle signal;

[0064] - Different ones of the duty cycle signals are input into different lines of the data selector;

[0065] - The data selector conducts the line associated with the control signal according to the control signal, and sends the duty cycle signal to the output unit through the line.

[0066] In another preferred embodiment of the present invention, the step of the duty cycle generation unit generating a corresponding duty cycle signal according to the control signal and sending it to the output unit includes:

[0067] - The duty cycle generation unit includes a PWM signal generation circuit and a duty cycle selection circuit;

[0068] - The PWM signal generation circuit is connected to different duty cycle circuits;

[0069] - The duty cycle generation unit connects different ones of the duty cycle circuits according to different control signals, and outputs different duty cycle signals to the output unit.

[0070] In another preferred embodiment of the present invention, according to the requirements of the vehicle BCM, the output unit is set to an open collector gate, a high-side drive, or a low-side drive.

[0071] It should be understood that the headlight function fault diagnosis method of the present invention can be implemented based on the structural units described in detail in the headlight function fault diagnosis system and its embodiments provided by the present invention. At the same time, it can also be implemented based on other devices that can implement this method.

[0072] It should be noted that the embodiments of the present invention have good implementation, and are not any form of limitation to the present invention. Any person skilled in the art may use the technical content disclosed above to change or modify it into an equivalent effective embodiment. However, as long as it does not depart from the content of the technical solution of the present invention, any modification, equivalent change, or modification made to the above embodiments according to the technical essence of the present invention still belongs to the scope of the technical solution of the present invention.

Claims

1. A method for diagnosing the functional failure of a vehicle lamp, characterized in that, It includes the following steps, At least one driving unit, at least one latching unit connected to the driving unit, a decoding unit connected to the latching unit, a duty ratio generating unit and an output unit connected to the decoding unit; The latching unit includes a first NPN transistor, a second NPN transistor and a PNP transistor, wherein the bases of the first NPN transistor and the second NPN transistor are both connected to the collector of the PNP transistor, the emitter of the first NPN transistor is grounded, the collector is connected to the base of the PNP transistor, the emitter of the second NPN transistor is also grounded, the collector is connected to the emitter of the PNP transistor, the collector of the PNP transistor is grounded, a power supply and a capacitor are connected between the base and the emitter of the PNP transistor, the capacitor is connected in parallel with the power supply, and the power supply is simultaneously connected to the collector of the first NPN transistor; The driving unit sends a first diagnostic signal to the latching unit, The latching unit processes the first diagnostic signal to form a stable second diagnostic signal and sends it to the decoding unit, The decoding unit generates a control signal according to the second diagnostic signal and sends it to the duty ratio generating unit, The duty ratio generating unit generates a corresponding duty ratio signal according to the control signal and sends it to the output unit, The output unit sends the duty ratio signal to the BCM of the vehicle; The step that the latching unit processes the first diagnostic signal to form a stable second diagnostic signal includes, The latching unit is a latching circuit, and the first diagnostic signal is an electrical signal, When the first diagnostic signal received by the latching circuit is at a low level, The latching function of the latching circuit is awakened, and the latching circuit reduces the level value of the first diagnostic signal so that the second diagnostic signal output from the latching circuit is at a low level, After the latching function of the latching circuit is awakened, when the latching unit receives the first diagnostic signal at a high level, it also outputs a low level as the second diagnostic signal; The step that the decoding unit generates a control signal according to the second diagnostic signal includes, The decoding unit determines whether a headlight function failure has occurred according to the second diagnostic signal, and analyzes the headlight function information of the headlight function failure according to the port information of the input port of the second diagnostic signal, Generates a control signal according to the port information and the headlight function information.

2. The headlight function failure diagnosis method according to claim 1, characterized in that, The power supply is connected to the BCM of the vehicle, The power supply receives the start signal of the BCM, supplies power to the latching circuit, and starts the latching circuit.

3. The headlight function failure diagnosis method according to claim 2, characterized in that, The decoding unit includes an input port, an output port and a decoding module, The number of the input ports is the same as the number of the driving units, The driving unit sends a first diagnostic signal to the latching unit, The decoding unit is configured to generate a control signal according to the second diagnostic signal and the input port information of the second diagnostic signal.

4. The headlight function fault diagnosis method according to claim 3, wherein the duty ratio generation unit includes a data selector, a PWM signal generator, and a duty ratio generation circuit, where the data selector is connected to the decoding unit, the duty ratio generation circuit is connected to the data selector, and the PWM signal generator is connected to the duty ratio generation circuit.

5. The headlight function fault diagnosis method according to claim 4, wherein the step that the duty ratio generation unit generates a corresponding duty ratio signal according to the control signal and sends it to the output unit includes the duty ratio generation circuit receives the PWM signal sent by the PWM signal generator and generates at least one duty ratio signal, different ones of the duty ratio signals are input into different lines of the data selector, the data selector conducts the line associated with the control signal according to the control signal, and sends the duty ratio signal to the output unit through the line.

6. The headlight function fault diagnosis method according to claim 3, wherein the step that the duty ratio generation unit generates a corresponding duty ratio signal according to the control signal and sends it to the output unit includes the duty ratio generation unit includes a PWM signal generation circuit and a duty ratio selection circuit, the PWM signal generation circuit accesses different duty ratio circuits, the duty ratio generation unit connects different ones of the duty ratio circuits according to different control signals and outputs different duty ratio signals to the output unit.

7. The headlight function fault diagnosis method according to claim 6, wherein according to the requirements of the vehicle BCM, the output unit is set as an OC gate, a high-side drive, or a low-side drive.

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