Natural gas engine injection driving protection circuit, driving circuit and control device

Abstract

The embodiment of the invention discloses a natural gas engine injection driving protection circuit, a driving circuit and a control device. The protection circuit comprises a resistor R1, a controllable switch Q1, a resistor R2, a capacitor C1 and a resistor R3. One end of the resistor R1 is connected with one end of the resistor R2 and one end of the jet coil, the other end of the resistor R1 is connected with a control end of the controllable switch Q1, and the other end of the resistor R2 is connected with a first wiring end of the controllable switch Q1; a second terminal of the controllable switch Q1 is connected with one end of the capacitor C1 and one end of the resistor R3 and then connected with an enabling end of the injection driving control chip T1, and the other end of the capacitor C1 is connected with the other end of the resistor R3 and then grounded. According to the invention, reliable and effective overcurrent protection is realized, the injection current sampling loop is short, the interference is small, and the output current value can be accurately controlled to change along with the change of the load. The device is simple in structure, small in size, low in cost and suitable for popularization and application.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of natural gas engines, and in particular to a natural gas engine injection drive protection circuit, a drive circuit and a control device. Background Art

[0002] People are becoming more and more environmentally conscious, and countries have formulated stricter standards for automobile emissions. Based on the above background, countries are prompted to continuously carry out technological innovation and product substitution in engine control, engine fuel sources and other aspects. Natural gas is the third largest natural energy source after coal and oil, and its reserves are abundant in nature. Natural gas can not only provide power performance comparable to oil, but also pollute the atmosphere much less. When the natural gas engine is working, the natural gas in the gas cylinder is pressure regulated, filtered, and injected into the gas mixer. The natural gas and air are mixed in a certain proportion in the gas mixer and then enter the intake manifold for final ignition and combustion. The reliability of the injection drive circuit plays a key role in the stability of the natural gas engine control system. However, the existing jet drive circuit still has the following shortcomings: 1. The overcurrent protection function of the jet drive circuit is poor. When an overcurrent fault occurs, the drive control chip cannot directly control the controllable switch on the jet drive circuit to turn off, the response speed is slow, and overcurrent protection cannot be performed in time; 2. The jet current sampling signal is easily interfered with, and the output current value cannot be accurately and stably controlled to change with the load; 3. The circuit implementation structure of the jet drive circuit itself, the overcurrent protection circuit, and the jet current sampling circuit is complex, large in size, and high in cost.

[0003] The above problems need to be solved urgently. Summary of the invention

[0004] In order to solve the related technical problems, the present invention provides a natural gas engine injection drive protection circuit, a drive circuit and a control device to solve the problems mentioned in the above background technology part.

[0005] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0006] In a first aspect, an embodiment of the present invention provides a natural gas engine injection drive protection circuit, comprising a resistor R1, a controllable switch Q1, a resistor R2, a capacitor C1 and a resistor R3; one end of the resistor R1 is connected to one end of the resistor R2 and one end of the injection coil, the other end of the resistor R1 is connected to the control end of the controllable switch Q1, the other end of the resistor R2 is connected to the first terminal of the controllable switch Q1, the second terminal of the controllable switch Q1 is connected to one end of the capacitor C1 and one end of the resistor R3 and then connected to the enable end of the injection drive control chip T1, the other end of the capacitor C1 is connected to the other end of the resistor R3 and then grounded.

[0007] As an optional implementation, the controllable switch Q1 adopts but is not limited to a PNP bipolar transistor; wherein the base of the controllable switch Q1 is the control terminal, the emitter of the controllable switch Q1 is the first terminal, and the collector of the controllable switch Q1 is the second terminal.

[0008] In a second aspect, an embodiment of the present invention provides a natural gas engine injection drive circuit, comprising a high-side drive power circuit, a low-side drive power circuit, an injection drive control chip T1, and the natural gas engine injection drive protection circuit proposed in the first aspect; the natural gas engine injection drive protection circuit comprises a resistor R1, a controllable switch Q1, a resistor R2, a capacitor C1, and a resistor R3; one end of the resistor R1 is connected to one end of the resistor R2 and one end of the injection coil, one end of the high-side drive power circuit is connected to the injection drive control chip T1, the other end of the injection coil is connected to the other end of the high-side drive power circuit, the other end of the resistor R1 is connected to the control end of the controllable switch Q1, the other end of the resistor R2 is connected to the first wiring terminal of the controllable switch Q1 and one end of the low-side drive power circuit, the other end of the low-side drive power circuit is connected to the injection drive control chip T1, the second wiring terminal of the controllable switch Q1 is connected to one end of the capacitor C1 and one end of the resistor R3, and then connected to the enable end of the injection drive control chip T1, the other end of the capacitor C1 is connected to the other end of the resistor R3 and then grounded.

[0009] As an optional implementation, the high-side drive power circuit includes a transistor Q2, a diode D1 and a transistor Q3; the gate of the transistor Q2 is connected to the injection drive control chip T1, and the drain of the transistor Q2 is connected to the high-voltage power supply end; the anode of the diode D1 is connected to the source of the transistor Q3, and the drain of the transistor Q3 is connected to the low-voltage power supply end; the cathode of the diode D1 is connected to one end of the injection coil and the source of the transistor Q2; the gate of the transistor Q3 is connected to the injection drive control chip T1.

[0010] As an optional implementation, the low-side drive power circuit includes a transistor Q4; the gate of the transistor Q4 is connected to the injection drive control chip T1, and the drain of the transistor Q4 is connected to one end of the resistor R1 and the control end of the controllable switch Q1.

[0011] As an optional implementation, the natural gas engine injection drive circuit also includes a drive current sampling circuit; the input end of the drive current sampling circuit is connected to the low-side drive power circuit, and the output end of the drive current sampling circuit is connected to the injection main control chip T2.

[0012] As an optional implementation, the controllable switch Q1 adopts but is not limited to a PNP bipolar transistor; wherein the base of the controllable switch Q1 is the control terminal, the emitter of the controllable switch Q1 is the first terminal, and the collector of the controllable switch Q1 is the second terminal.

[0013] As an optional implementation, the transistor Q2, the transistor Q3, and the transistor Q4 are all but limited to insulated gate field effect transistors.

[0014] In a third aspect, an embodiment of the present invention provides a natural gas engine injection control device, which includes the natural gas engine injection drive circuit proposed in the second aspect.

[0015] The technical solution proposed in the embodiment of the present invention generates a voltage on the resistor R1 when there is an overcurrent, and the controllable switch Q1 is controlled to be turned on and off by the voltage. When the controllable switch Q1 is turned on, the current generates a voltage divider on the resistors R2 and R3. After the voltage is greater than the protection threshold of the injection drive control chip T1, the injection drive control chip T1 can directly turn off the high-side drive power circuit and the low-side drive power circuit, and the response speed is fast, thereby realizing reliable, effective and fast overcurrent protection for the injection drive circuit of the natural gas engine. The technical solution proposed in the embodiment of the present invention samples the injection current through the resistor R4, and the sampled signal is processed by the operational amplifier U1 and the operational amplifier U2 and then input into the injection main control chip T2. The injection main control chip T2 uses the output signals of the operational amplifier U1 and the operational amplifier U2 as the injection current control signal to adjust the controllable switches of the high-side drive power circuit and the low-side drive power circuit, thereby completing the control and adjustment of the injection current. The signal loop is short, the interference is small, and the output current value can be accurately and stably controlled to change with the load. The technical solution proposed in the embodiment of the present invention optimizes the structure of the injection driving circuit, the overcurrent protection circuit, and the injection current sampling circuit, has a small size, low cost, and is suitable for popularization and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate and understand the technical solutions in the embodiments of the present invention, the following briefly introduces the background technology of the present invention and the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0017] Figure 1 A structural diagram of a natural gas engine jet drive protection circuit provided in Embodiment 1 of the present invention;

[0018] Figure 2This is a structural diagram of the natural gas engine injection drive circuit provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0019] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0020] Embodiment 1

[0021] Please refer to Figure 1 As stated, Figure 1 This is a structural diagram of a natural gas engine injection drive protection circuit provided in Embodiment 1 of the present invention. As shown in the figure, the natural gas engine injection drive protection circuit in this embodiment includes a resistor R1, a controllable switch Q1, a resistor R2, a capacitor C1 and a resistor R3.

[0022] In this embodiment, one end of the resistor R1 is connected to one end of the resistor R2 and one end of the injection coil, the other end of the resistor R1 is connected to the control end of the controllable switch Q1, the other end of the resistor R2 is connected to the first terminal of the controllable switch Q1, the second terminal of the controllable switch Q1 is connected to one end of the capacitor C1 and one end of the resistor R3 and then connected to the enable end of the injection drive control chip T1, and the other end of the capacitor C1 is connected to the other end of the resistor R3 and then grounded.

[0023] Exemplarily, the controllable switch Q1 adopts but is not limited to a PNP bipolar transistor; wherein the base of the controllable switch Q1 is the control terminal, the emitter of the controllable switch Q1 is the first terminal, and the collector of the controllable switch Q1 is the second terminal.

[0024] Specifically, when the driving circuit is overcurrent, a voltage is generated on the resistor R1, and the controllable switch Q1 is controlled to be turned on and off by the voltage. Taking the controllable switch Q1 using a PNP bipolar transistor as an example, when the emitter voltage of the PNP bipolar transistor is greater than the base voltage and greater than the set threshold, the PNP bipolar transistor is turned on. At this time, the current generates a divided voltage on R2 and the resistor R3. After the voltage is greater than the protection threshold of the jet drive control chip T1, the jet drive control chip T1 can directly turn off the high-side drive power circuit and the low-side drive power circuit.

[0025] Compared with the conventional low-side drive series current sampling resistor in the natural gas engine injection drive circuit, the injection main control chip outputs the control signal to the injection drive control chip after collecting the voltage on the resistor, thereby realizing the overcurrent protection action, the natural gas engine injection drive protection circuit proposed in this embodiment directly turns off the high-side drive power circuit and the low-side drive power circuit when the drive circuit is overcurrent, greatly reducing the transmission path and protection delay, and effectively avoiding the problem that the series resistor is overheated and damaged due to the increase of current in the traditional solution when an overcurrent fault occurs, and considering the use of reduced power, multiple currents are usually required to be used in parallel, resulting in increased costs. Compared with the conventional current transformer solution, the natural gas engine injection drive protection circuit proposed in this embodiment also solves the shortcomings of the conventional current transformer overcurrent protection solution, has a fast response speed, realizes reliable, effective and fast overcurrent protection for the natural gas engine injection drive circuit, and has a simple structure, small size and low cost. The traditional current transformer solution refers to using a current transformer to collect the load coil current, directly collecting the jet coil current through the current transformer, and then converting the collected current signal into a voltage signal and inputting it into the jet main control chip for overcurrent protection; this solution couples the auxiliary winding with the load coil to form a current transformer to collect the load current, and after signal processing, the collected signal is sent to the jet drive control chip for judgment. However, the implementation of this solution requires the addition of an auxiliary coil as a current transformer function, which is complex, increases the product size and cost, and the current transformer has a slow response to current coupling, and cannot provide timely protection when a large current short circuit occurs.

[0026] The natural gas engine injection drive protection circuit proposed in this embodiment has a fast response speed, realizes reliable, effective and fast overcurrent protection for the natural gas engine injection drive circuit, and has a simple structure, small size and low cost, and is suitable for promotion and application.

[0027] Embodiment 2

[0028] Please refer to Figure 2 As stated, Figure 2 This is a structural diagram of a natural gas engine injection drive circuit provided in the second embodiment of the present invention. As shown in the figure, the natural gas engine injection drive circuit in this embodiment includes a high-side drive power circuit, a low-side drive power circuit, an injection drive control chip T1, and the natural gas engine injection drive protection circuit proposed in the first embodiment above.

[0029] In this embodiment, the natural gas engine injection drive protection circuit includes a resistor R1, a controllable switch Q1, a resistor R2, a capacitor C1 and a resistor R3; one end of the resistor R1 is connected to one end of the resistor R2 and one end of the injection coil, one end of the high-side drive power circuit is connected to the injection drive control chip T1, the other end of the injection coil is connected to the other end of the high-side drive power circuit, the other end of the resistor R1 is connected to the control end of the controllable switch Q1, the other end of the resistor R2 is connected to the first terminal of the controllable switch Q1 and one end of the low-side drive power circuit, the other end of the low-side drive power circuit is connected to the injection drive control chip T1, the second terminal of the controllable switch Q1 is connected to one end of the capacitor C1 and one end of the resistor R3, and then connected to the enable end of the injection drive control chip T1, and the other end of the capacitor C1 is connected to the other end of the resistor R3 and then grounded.

[0030] Exemplarily, the high-side drive power circuit includes a transistor Q2, a diode D1 and a transistor Q3; the gate of the transistor Q2 is connected to the injection drive control chip T1, and the drain of the transistor Q2 is connected to the high-voltage power supply end; the anode of the diode D1 is connected to the source of the transistor Q3, and the drain of the transistor Q3 is connected to the low-voltage power supply end; the cathode of the diode D1 is connected to one end of the injection coil and the source of the transistor Q2; the gate of the transistor Q3 is connected to the injection drive control chip T1.

[0031] Exemplarily, the low-side drive power circuit includes a transistor Q4; the gate of the transistor Q4 is connected to the injection drive control chip T1, and the drain of the transistor Q4 is connected to one end of the resistor R1 and the control end of the controllable switch Q1.

[0032] Exemplarily, the natural gas engine injection drive circuit further includes a drive current sampling circuit; the input end of the drive current sampling circuit is connected to the low-side drive power circuit, and the output end of the drive current sampling circuit is connected to the injection main control chip T2.

[0033] In this embodiment, the driving current sampling circuit includes a resistor R4, a resistor R5, a resistor R6, an operational amplifier U1, a capacitor C2, a resistor R7, a resistor R8 and an operational amplifier U2; one end of the resistor R4 is connected to the source of the transistor Q4 and one end of the resistor R5, the other end of the resistor R4 is connected to one end of the resistor R6, one end of the resistor R7, and one end of the resistor R9 and then grounded, the other end of the resistor R5 is connected to one end of the resistor R8 and the first input end of the operational amplifier U1, the other end of the resistor R6 is connected to the other end of the resistor R7 and the second input end of the operational amplifier U1, the other end of the resistor R8 is connected to the output end of the operational amplifier U1 and one end of the resistor R10, the other end of the resistor R10 is connected to one end of the capacitor C2 and the first input end of the operational amplifier U2, the second input end of the operational amplifier U2 is connected to the other end of the resistor R9, and the other end of the capacitor C2 is connected to the output end of the operational amplifier U2 and then connected to the injection main control chip T2.

[0034] In this embodiment, the controllable switch Q1 is a PNP bipolar transistor, wherein the base of the controllable switch Q1 is the control terminal, the emitter of the controllable switch Q1 is the first terminal, and the collector of the controllable switch Q1 is the second terminal. In this embodiment, the transistors Q2, Q3, and Q4 are all insulated gate field effect transistors, but are not limited to them.

[0035] Specifically, when the driving circuit is overcurrent, a voltage is generated on the resistor R1, and the controllable switch Q1 is controlled to be turned on and off by the voltage. Taking the controllable switch Q1 using a PNP bipolar transistor as an example, when the emitter voltage of the PNP bipolar transistor is greater than the base voltage and greater than the set threshold, the PNP bipolar transistor is turned on. At this time, the current generates a divided voltage on R2 and the resistor R3. After the voltage is greater than the protection threshold of the jet drive control chip T1, the jet drive control chip T1 can directly turn off the high-side drive power circuit and the low-side drive power circuit.

[0036] Compared with the conventional scheme of low-side drive series current sampling resistor in the natural gas engine injection drive circuit, the injection main control chip outputs the control signal to the injection drive control chip after collecting the voltage on the resistor, thereby realizing the overcurrent protection action, the natural gas engine injection drive protection circuit in the natural gas engine injection drive circuit proposed in this embodiment directly turns off the high-side drive power circuit and the low-side drive power circuit when the drive circuit is overcurrent, greatly reducing the transmission path and protection delay, and effectively avoiding the problem that the increase of current in the traditional scheme causes the series resistor to overheat and damage when an overcurrent fault occurs, and considering the use of reduced power, multiple currents are usually required to be used in parallel, resulting in increased costs. Compared with the conventional current transformer scheme, the natural gas engine injection drive protection circuit in the natural gas engine injection drive circuit proposed in this embodiment also solves the shortcomings of the conventional current transformer overcurrent protection scheme, has a fast response speed, realizes reliable, effective and fast overcurrent protection for the natural gas engine injection drive circuit, and has a simple structure, small size and low cost. The traditional current transformer solution refers to using a current transformer to collect the load coil current, directly collecting the jet coil current through the current transformer, and then converting the collected current signal into a voltage signal and inputting it into the jet main control chip for overcurrent protection; this solution couples the auxiliary winding with the load coil to form a current transformer to collect the load current, and after signal processing, the collected signal is sent to the jet drive control chip for judgment. However, the implementation of this solution requires the addition of an auxiliary coil as a current transformer function, which is complex, increases the product size and cost, and the current transformer has a slow response to current coupling, and cannot provide timely protection when a large current short circuit occurs.

[0037] Specifically, the driving current sampling circuit in the natural gas engine injection drive circuit proposed in this embodiment samples the injection current through the resistor R4, and the sampled signal is processed by the operational amplifier U1 and the operational amplifier U2 and then input into the injection main control chip T2. The injection main control chip T2 uses the output signals of the operational amplifier U1 and the operational amplifier U2 as the injection current control signal to perform PWM regulation on the transistor Q2 and the transistor Q3 of the high-side drive power circuit, and the transistor Q4 of the low-side drive power circuit, so as to complete the control and regulation of the injection current, and effectively solves the problem that the traditional solution has a low-side drive series current sampling resistor in the natural gas engine injection drive circuit, and the voltage is collected from the low-side drive sampling resistor and then input into the injection main control chip T2, and the signal loop is long and the signal is easily affected. The signal loop is short and the interference is small, and the output current value can be accurately and stably controlled to change with the load, which is suitable for promotion and application.

[0038] Embodiment 3

[0039] An embodiment of the present invention provides a natural gas engine injection control device, which includes the natural gas engine injection drive circuit proposed in the above-mentioned embodiment 2.

[0040] The natural gas engine injection control device proposed in the embodiment of the present invention realizes reliable, effective and fast overcurrent protection for the natural gas engine injection drive circuit. The injection current sampling loop in the natural gas engine injection control device proposed in the embodiment of the present invention is short and has small interference, and can accurately and stably control the output current value to change with the load. The natural gas engine injection control device proposed in the embodiment of the present invention optimizes the injection drive circuit, overcurrent protection circuit, and injection current sampling circuit structure, is small in size, low in cost, and suitable for popularization and application.

[0041] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A natural gas engine injection drive protection circuit, characterized in that: The circuit includes a resistor R1, a controllable switch Q1, a resistor R2, a capacitor C1 and a resistor R3; one end of the resistor R1 is connected to one end of the resistor R2 and one end of the injection coil, the other end of the resistor R1 is connected to the control end of the controllable switch Q1, the other end of the resistor R2 is connected to the first terminal of the controllable switch Q1, the second terminal of the controllable switch Q1 is connected to one end of the capacitor C1 and one end of the resistor R3 and then connected to the enable end of the injection drive control chip T1, and the other end of the capacitor C1 is connected to the other end of the resistor R3 and then grounded.

2. The natural gas engine injection drive protection circuit according to claim 1, characterized in that: The controllable switch Q1 adopts but is not limited to a PNP bipolar transistor; wherein the base of the controllable switch Q1 is the control terminal, the emitter of the controllable switch Q1 is the first terminal, and the collector of the controllable switch Q1 is the second terminal.

3. A natural gas engine injection drive circuit, characterized in that: The invention comprises a high-side drive power circuit, a low-side drive power circuit, an injection drive control chip T1 and the natural gas engine injection drive protection circuit according to claim 1; the natural gas engine injection drive protection circuit comprises a resistor R1, a controllable switch Q1, a resistor R2, a capacitor C1 and a resistor R3; one end of the resistor R1 is connected to one end of the resistor R2 and one end of the injection coil, one end of the high-side drive power circuit is connected to the injection drive control chip T1, the other end of the injection coil is connected to the other end of the high-side drive power circuit, the other end of the resistor R1 is connected to the control end of the controllable switch Q1, the other end of the resistor R2 is connected to the first terminal of the controllable switch Q1 and one end of the low-side drive power circuit, the other end of the low-side drive power circuit is connected to the injection drive control chip T1, the second terminal of the controllable switch Q1 is connected to one end of the capacitor C1 and one end of the resistor R3 and then connected to the enable end of the injection drive control chip T1, the other end of the capacitor C1 is connected to the other end of the resistor R3 and then grounded.

4. The natural gas engine injection drive circuit according to claim 3, characterized in that: The high-side drive power circuit includes a transistor Q2, a diode D1 and a transistor Q3; the gate of the transistor Q2 is connected to the jet drive control chip T1, and the drain of the transistor Q2 is connected to the high-voltage power supply end; the anode of the diode D1 is connected to the source of the transistor Q3, and the drain of the transistor Q3 is connected to the low-voltage power supply end; the cathode of the diode D1 is connected to one end of the jet coil and the source of the transistor Q2; the gate of the transistor Q3 is connected to the jet drive control chip T1.

5. The natural gas engine injection drive circuit according to claim 4, characterized in that: The low-side drive power circuit includes a transistor Q4; the gate of the transistor Q4 is connected to the injection drive control chip T1, and the drain of the transistor Q4 is connected to one end of the resistor R1 and the control end of the controllable switch Q1.

6. The natural gas engine injection drive circuit according to claim 5, characterized in that: It also includes a driving current sampling circuit; the input end of the driving current sampling circuit is connected to the low-side driving power circuit, and the output end of the driving current sampling circuit is connected to the injection main control chip T2.

7. The natural gas engine injection drive circuit according to claim 6, characterized in that: The controllable switch Q1 adopts but is not limited to a PNP bipolar transistor; wherein the base of the controllable switch Q1 is the control terminal, the emitter of the controllable switch Q1 is the first terminal, and the collector of the controllable switch Q1 is the second terminal.

8. The natural gas engine injection drive circuit according to claim 4, characterized in that: The transistor Q2, the transistor Q3 and the transistor Q4 are all but not limited to insulated gate field effect transistors.

9. A natural gas engine injection control device, characterized in that: The device comprises the natural gas engine injection driving circuit according to any one of claims 3 to 8.

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