An ECU diagnostic detection signal current and primary current feedback circuit

Abstract

The present invention discloses an ECU diagnostic detection signal current and primary current feedback circuit, comprising an input signal current processing unit, an ignition drive unit, an ignition IGBT, a primary current feedback sampling unit and a primary current processing unit; wherein: the input signal current processing unit is arranged at the ECU signal input end, and is used to keep the input signal current within the ECU detection diagnosis range; the ignition drive unit is connected to the ignition IGBT, and is used to receive the input ECU signal, and drive the ignition IGBT to turn on or off according to the ECU signal; the ignition IGBT is connected to the ignition coil, and is used to control the operation of the ignition coil; the primary current feedback sampling unit is connected to the emitter of the ignition IGBT, and is used to sample the primary current of the ignition coil, and output the sampling result to the primary current processing unit; the primary current processing unit is used to judge and process the primary current sampling result, and then output the primary current feedback signal to the ECU. The present invention adopts IGBT as the power tube of the ignition module and is a pure hardware solution, and keeps the signal current within the ECU detection diagnosis range by processing the signal input end, and feeds back the signal current and the primary current to the ECU, so that the ECU can correctly diagnose and detect the state of the ignition coil, and ensure that the ignition coil works normally and stably.

Description

Technical Field

[0001] The invention relates to the technical field of automobile engine electronic ignition control, and in particular to an ECU diagnosis detection signal current and primary current feedback circuit. Background Art

[0002] In the field of electronic ignition control of automobile engines, ECU refers to the electronic control unit of the engine, and the ECU signal refers to the EST control signal output by the ECU. The ignition module of the automobile engine control system controls the ignition coil to ignite according to the ECU signal. When the ECU signal is high, the primary of the ignition coil is turned on, and the primary current increases with the conduction time; when the ECU signal is low, the primary current of the ignition coil is turned off, and the secondary of the ignition coil generates a high voltage to complete the ignition function.

[0003] When the automobile ECU ignition diagnosis detects the signal current and primary current, if the power tube used on the ignition module is a Darlington tube, the signal current of the Darlington tube is relatively high, usually 30-50mA, but the ECU detection signal current of some models is relatively low, below 20mA. In this case, if the ignition module continues to use the Darlington tube, it will cause the ECU ignition diagnosis to be abnormal. In the prior art, when the power tube used on the ignition module is a Darlington tube, and the ECU detection signal current is relatively low, the solutions used on the ignition module are usually: 1) a specially customized IC integration solution, which is costly and requires customization; 2) a combination of software and hardware, which requires the addition of additional peripheral circuits, increases the size of the ignition module, makes layout difficult, increases the number of devices too much, and is prone to failure. Summary of the invention

[0004] The purpose of the present invention is to provide an ECU diagnostic detection signal current and primary current feedback circuit. The power tube of the ignition module adopts IGBT and a pure hardware solution. By processing the signal input end, the signal current is kept within the ECU detection and diagnosis range, and the signal current and primary current are fed back to the ECU, so that the ECU can correctly diagnose and detect the state of the ignition coil, ensuring that the ignition coil works normally and stably.

[0005] In order to achieve the above purpose, the following technical solutions are adopted:

[0006] An ECU diagnostic detection signal current and primary current feedback circuit comprises an input signal current processing unit, an ignition drive unit, an ignition IGBT, a primary current feedback sampling unit and a primary current processing unit; wherein: the input signal current processing unit is arranged at the ECU signal input end, and is used to keep the input signal current within the ECU detection and diagnosis range; the ignition drive unit is connected to the ignition IGBT, and is used to receive the input ECU signal and drive the ignition IGBT to turn on or off according to the ECU signal; the ignition IGBT is connected to the ignition coil, and is used to control the operation of the ignition coil; the primary current feedback sampling unit is connected to the emitter of the ignition IGBT, and is used to sample the primary current of the ignition coil and output the sampling result to the primary current processing unit; the primary current processing unit is used to output the primary current feedback signal to the ECU after judging and processing the primary current sampling result.

[0007] Preferably, the input signal current processing unit comprises a resistor R12, a resistor R14, and a voltage regulator D5; the resistor R12 is connected in series with the voltage regulator D5 and then connected in parallel with the resistor R14.

[0008] Preferably, it also includes an LDO unit connected to the power supply end; the LDO unit is used to provide a stable voltage source for the ignition drive unit and the primary current processing unit.

[0009] Preferably, the LDO unit includes a voltage regulator tube D4 and a switch tube Q2; after the power supply voltage is stabilized by the voltage regulator tube D4, the switch tube Q2 is controlled to be turned on to generate a stable voltage source.

[0010] Preferably, the ignition drive unit includes a comparator U1A, a resistor R1, and a resistor R13; the resistor R1 and the resistor R13 are connected in series; the stable voltage source provided by the LDO unit is input into the inverting input terminal of the comparator U1A after voltage division by the resistors R1 and R13, and the ECU signal is input into the non-inverting input terminal of the comparator U1A.

[0011] Preferably, the primary current processing unit includes a comparator U1B, a resistor R7, and a resistor R8; the resistor R7 and the resistor R8 are connected in series; the stable voltage source provided by the LDO unit is input into the non-inverting input terminal of the comparator U1B after voltage division by the resistors R7 and R8, and the sampling result of the primary current feedback sampling unit is input into the inverting input terminal of the comparator U1B.

[0012] By adopting the above scheme, the beneficial effects of the present invention are:

[0013] The present invention adopts IGBT and pure hardware solution through the power tube of the ignition module, processes the signal input end so that the signal current is kept within the detection and diagnosis range of the ECU, and feeds back the signal current and the primary current to the ECU, so that the ECU can correctly diagnose and detect the state of the ignition coil, ensuring that the ignition coil works normally and stably. At the same time, the present invention adopts a discrete device solution, does not require a specially customized IC integration solution and software control, does not require the addition of too many devices, has a small module size, and is low in cost. It can effectively extend the service life of the ignition module, reduce the failure rate of the ignition coil, and ensure that the ignition coil is effectively and stably ignited, thereby ensuring the power stability of the vehicle and reducing exhaust emission pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a principle block diagram of the present invention;

[0015] Figure 2 It is the circuit principle diagram of the present invention;

[0016] The accompanying drawings illustrate:

[0017] 1—Input signal current processing unit, 2—Ignition drive unit,

[0018] 3—primary current feedback sampling unit, 4—primary current processing unit,

[0019] 5—LDO unit. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0021] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0022] In the description of this embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0023] Reference Figures 1 to 2 As shown, the present invention provides an ECU diagnostic detection signal current and primary current feedback circuit, including an input signal current processing unit 1, an ignition drive unit 2, an ignition IGBT Q1, a primary current feedback sampling unit 3 and a primary current processing unit 4; wherein: the input signal current processing unit 1 is arranged at the ECU signal input end, and is used to keep the input signal current within the ECU detection and diagnosis range; the ignition drive unit 2 is connected to the ignition IGBT Q1, and is used to receive the input ECU signal, and drive the ignition IGBT Q1 to be turned on or off according to the ECU signal; the ignition IGBT Q1 is connected to the ignition coil, and is used to control the operation of the ignition coil; the primary current feedback sampling unit 3 is connected to the emitter of the ignition IGBT Q1, and is used to sample the primary current of the ignition coil, and output the sampling result to the primary current processing unit 4; the primary current processing unit 4 is used to output the primary current feedback signal to the ECU after judging and processing the primary current sampling result.

[0024] The present invention provides an ECU diagnostic detection signal current and primary current feedback circuit, which can achieve the following purposes:

[0025] 1) The power tube of the ignition module adopts IGBT and is a pure hardware solution. By processing the signal input end, the signal current is kept within the ECU detection and diagnosis range, that is, the signal current can adapt to the ECU detection and diagnosis range to avoid abnormal diagnosis;

[0026] 2) The discrete device solution is adopted, which does not require customized IC integration solutions and software control, does not require the addition of too many devices, and the module size is small and the cost is low.

[0027] Input signal current processing unit 1:

[0028] The input signal current processing unit 1 includes a resistor R12, a resistor R14, and a voltage regulator D5; the resistor R12 is connected in series with the voltage regulator D5 and then connected in parallel with the resistor R14. Since the signal currents detected by different vehicle models are different, by adjusting the device parameters of the resistor R12, the voltage regulator D5, and the resistor R14, when the device parameters are set reasonably, the signal current will stabilize in a fixed state, so that the signal current remains within the ECU detection and diagnosis range. When the signal current meets the detection range during ECU diagnosis, the ECU outputs a normal and stable signal, and the ignition module works normally.

[0029] LDO Unit 5:

[0030] The present invention provides an ECU diagnostic detection signal current and primary current feedback circuit, which also includes an LDO unit 5 connected to the power supply end; the LDO unit 5 is used to provide a stable voltage source for the ignition drive unit 2 and the primary current processing unit 4. The LDO unit 5 includes a voltage regulator tube D4 and a switch tube Q2; after the power supply voltage is stabilized by the voltage regulator tube D4, the switch tube Q2 is controlled to be turned on to generate a stable voltage source. The LDO unit 5 plays a role in outputting a stable voltage. If the power supply voltage is interfered or unstable, the LDO unit 5 will play a key role.

[0031] Ignition drive unit 2 :

[0032] The ignition drive unit 2 includes a comparator U1A, a resistor R1, and a resistor R13; the resistor R1 and the resistor R13 are connected in series; the stable voltage source provided by the LDO unit 5 is input to the inverting input terminal of the comparator U1A after being divided by the resistors R1 and R13, and the ECU signal is input to the non-inverting input terminal of the comparator U1A.

[0033] The stable voltage source provided by the LDO unit 5 is input to the inverting input terminal (reference terminal) of the comparator U1A after being divided by the resistors R1 and R13. The comparator U1A compares the ECU signal with the reference value of the reference terminal to output a driving signal to the ignition IGBT Q1.

[0034] Primary current feedback sampling unit 3:

[0035] In a specific embodiment, the primary current feedback sampling unit 3 includes a sampling resistor R5, one end of which is connected to the emitter of the ignition IGBT Q1, and the other end is grounded. The input end of the primary current processing unit 4 is connected between the sampling resistor R5 and the emitter of the ignition IGBT Q1. After the ignition IGBT Q1 is turned on, the primary current flows through its emitter, and is sampled at this position by the sampling resistor R5 and input into the primary current processing unit 4.

[0036] Primary current processing unit 4:

[0037] The primary current processing unit 4 includes a comparator U1B, a resistor R7, and a resistor R8; the resistor R7 and the resistor R8 are connected in series; the stable voltage source provided by the LDO unit 5 is input to the non-inverting input terminal of the comparator U1B after being divided by the resistors R7 and R8, and the sampling result of the primary current feedback sampling unit 3 is input to the inverting input terminal of the comparator U1B.

[0038] The stable voltage source provided by the LDO unit 5 is input to the positive input terminal of the comparator U1B after being divided by resistors R7 and R8. When the power is turned on, the input of the positive input terminal of the comparator U1B is a fixed value. The primary current feedback sampling unit 3 inputs the inverting input terminal of the comparator U1B as a reference value. By comparing the fixed value with the reference value, the primary current feedback signal is output to the ECU.

[0039] In addition, the present invention provides an ECU diagnostic detection signal current and primary current feedback circuit, which has two ECU diagnostic functions: signal current detection and primary current detection:

[0040] 1) Detection signal current diagnosis: ECU sends a driving signal. After the ECU signal is input, it is diagnosed whether the input signal is normal. The input signal current processing unit 1 processes it so that the processed signal current remains within the ECU detection diagnosis range;

[0041] 2) Detection of primary current diagnosis: The primary current feedback sampling unit 3 samples the emitter of the ignition IGBT Q1, and outputs the primary current feedback signal to the ECU through processing by the primary current processing unit 4 to diagnose whether the ignition is normal.

[0042] The working process of the present invention is as follows:

[0043] 1) When the ECU does not send an ignition signal, the ignition IGBT Q1 is in the off state;

[0044] 2) When the ECU sends an ignition signal (pulse square wave signal), the signal current at the input end will be processed by the input signal current processing unit 1 to keep the signal current within the ECU detection and diagnosis range;

[0045] 3) The ignition signal sent by the ECU is also input to the non-inverting input terminal of the comparator U1A in the ignition drive unit 2. By comparing with the reference terminal (inverting input terminal) of the comparator U1A, when the input value of the non-inverting input terminal is greater than the set reference value, the comparator U1A is turned on, and the output signal turns on the ignition IGBT Q1;

[0046] 4) After the ignition IGBT Q1 is turned on, the primary current flows through its emitter, is sampled through the sampling resistor R5, and is output to the inverting input terminal of the comparator U1B; when the ignition IGBT Q1 is not working, the input value of the non-inverting input terminal of the comparator U1B is greater than the reference value, and the comparator U1B is turned on to output the primary current feedback signal to the ECU, allowing the ECU to determine the working status of the ignition coil. At this time, the ECU will also detect the signal current characteristics at the signal input terminal (signal current detection); when the ignition IGBT Q1 is working, the input value of the non-inverting input terminal of the comparator U1B is less than the reference value of the inverting input terminal of the comparator U1B, and the comparator U1B is turned off.

[0047] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention. Obviously, the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An ECU diagnostic detection signal current and primary current feedback circuit, characterized in that: It includes an input signal current processing unit, an ignition drive unit, an ignition IGBT, a primary current feedback sampling unit and a primary current processing unit; wherein: An input signal current processing unit is provided at the ECU signal input terminal and is used to keep the input signal current within the ECU detection and diagnosis range; An ignition drive unit is connected to the ignition IGBT, and is used to receive an input ECU signal and drive the ignition IGBT to turn on or off according to the ECU signal; Ignition IGBT, connected to the ignition coil, used to control the operation of the ignition coil; A primary current feedback sampling unit is connected to the emitter of the ignition IGBT, and is used to sample the primary current of the ignition coil and output the sampling result to the primary current processing unit; The primary current processing unit is used to judge and process the primary current sampling result and output the primary current feedback signal to the ECU; It also includes an LDO unit connected to the power supply end; the LDO unit is used to provide a stable voltage source for the ignition drive unit and the primary current processing unit; The LDO unit includes a voltage regulator tube D4 and a switch tube Q2; after the power supply voltage is stabilized by the voltage regulator tube D4, the switch tube Q2 is controlled to be turned on to generate a stable voltage source; The input signal current processing unit includes a resistor R12, a resistor R14, a voltage regulator D5, and a resistor R11; the resistor R12 is connected in series with the voltage regulator D5, and then connected in parallel with the resistor R14 and the resistor R11.

2. The ECU diagnostic detection signal current and primary current feedback circuit according to claim 1, characterized in that: The ignition drive unit includes a comparator U1A, a resistor R1, and a resistor R13; the resistor R1 and the resistor R13 are connected in series; the stable voltage source provided by the LDO unit is input to the inverting input terminal of the comparator U1A after being divided by the resistors R1 and R13, and the ECU signal is input to the non-inverting input terminal of the comparator U1A.

3. The ECU diagnostic detection signal current and primary current feedback circuit according to claim 1, characterized in that: The primary current processing unit includes a comparator U1B, a resistor R7, and a resistor R8; the resistor R7 and the resistor R8 are connected in series; the stable voltage source provided by the LDO unit is input into the non-inverting input terminal of the comparator U1B after voltage division by the resistors R7 and R8, and the sampling result of the primary current feedback sampling unit is input into the inverting input terminal of the comparator U1B.

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