Natural gas engine injection driving protection circuit and injection driving device

Abstract

The embodiment of the utility model discloses a natural gas engine injection driving protection circuit and an injection driving 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 utility model, reliable and effective over-current protection is realized, the injection current sampling loop is short, and interference is small. 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 utility model relate to the technical field of natural gas engines, and in particular to a natural gas engine jet drive protection circuit and a jet drive device. Background Art

[0002] When a natural gas engine is operating, the natural gas in the gas cylinder is pressure-regulated, filtered, and injection-controlled, then 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 jet drive device plays a key role in the stability of the natural gas engine control system. However, existing jet drive devices still have the following deficiencies: 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, resulting in a slow response speed and inability to provide timely overcurrent protection; 2. The jet current sampling signal is easily interfered with, making it impossible to accurately and stably control the output current value to change with changes in 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. Utility Model Content

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

[0005] To achieve the above objectives, the present invention adopts 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 connected to ground.

[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 jet drive device, comprising a high-side drive power circuit, a low-side drive power circuit, a jet drive control chip T1, and the natural gas engine jet drive protection circuit proposed in the first aspect above; the natural gas engine jet 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 jet coil, one end of the high-side drive power circuit is connected to the jet drive control chip T1, the other end of the jet 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 jet 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 to the enable terminal of the jet drive control chip T1, the other end of the capacitor C1 is connected to the other end of the resistor R3, and then to ground.

[0009] As an optional embodiment, 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 embodiment, the natural gas engine injection drive device 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.

[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] The technical solution proposed in the embodiment of the utility model generates a voltage across resistor R1 when overcurrent occurs. This voltage controls the on and off of controllable switch Q1. When controllable switch Q1 is on, the current generates a voltage divider across resistors R2 and R3. When the voltage exceeds the protection threshold of the jet drive control chip T1, the jet drive control chip T1 can directly shut down the high-side drive power circuit and the low-side drive power circuit. This provides fast response speed and achieves reliable, effective, and rapid overcurrent protection for the natural gas engine jet drive device. The technical solution proposed in the embodiment of the utility model samples the jet current through resistor R4. The sampled signal is processed by operational amplifiers U1 and U2 and then input into the jet main control chip T2. The jet main control chip T2 uses the output signals of operational amplifiers U1 and U2 as the jet current control signals to adjust the controllable switches of the high-side drive power circuit and the low-side drive power circuit, thereby completing the control and regulation of the jet current. The signal loop is short, interference is low, and the output current value can be accurately and stably controlled to change with changes in load. The technical solution proposed in the embodiment of the utility model optimizes the structures of the ejection drive circuit, the overcurrent protection circuit, and the ejection current sampling circuit, has a small size, low cost, and is suitable for popularization and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate and understand the technical solutions in the embodiments of the present invention, a brief introduction is given below to 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.

[0016] Figure 1 This is a structural diagram of a natural gas engine jet drive protection circuit provided by the first embodiment of the present utility model;

[0017] Figure 2 This is a structural diagram of the natural gas engine jet drive device provided in Example 2 of the present utility model. DETAILED DESCRIPTION

[0018] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved more clearly, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work shall fall within the scope of protection of the present invention.

[0019] Example 1

[0020] Please refer to Figure 1 As stated, Figure 1 This is a structural diagram of a natural gas engine jet drive protection circuit according to a first embodiment of the present invention. As shown in the figure, the natural gas engine jet drive protection circuit according to this embodiment includes a resistor R1, a controllable switch Q1, a resistor R2, a capacitor C1, and a resistor R3.

[0021] 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.

[0022] Exemplarily, the controllable switch Q1 is but 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.

[0023] Specifically, when the driving circuit has an 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 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. When 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.

[0024] Compared to conventional solutions that implement overcurrent protection by connecting a current sampling resistor in series with the low-side driver of a natural gas engine jet drive device, sampling the voltage across the resistor and transmitting it to the jet drive control chip. The jet drive control chip then determines whether an overcurrent fault has occurred in the drive circuit and outputs a control signal to the jet drive control chip. In this embodiment, the natural gas engine jet drive protection circuit directly shuts down both the high-side and low-side driver power circuits when an overcurrent occurs in the drive circuit. This significantly reduces the transmission path and protection delay, effectively avoiding the problems of conventional solutions that often involve overheating and damage to the series resistor due to increased current during an overcurrent fault, as well as the cost increase associated with the need for multiple current transformers to be connected in parallel to reduce power consumption. Compared to conventional current transformer solutions, the natural gas engine jet drive protection circuit proposed in this embodiment also addresses the shortcomings of conventional current transformer overcurrent protection solutions, offering a fast response time and reliable, effective, and rapid overcurrent protection for natural gas engine jet drive devices. Furthermore, it features a simple structure, compact size, and low cost. The traditional current transformer solution uses 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 that is input to the jet main control chip for overcurrent protection. This solution couples an auxiliary winding with the load coil to form a current transformer to collect the load current. After signal processing, the collected signal is sent to the jet drive control chip for judgment. However, implementing this solution requires adding an auxiliary coil to function as a current transformer, which is complex and increases product size and cost. Moreover, the current transformer's response time for current coupling is slow, and when a high current short circuit occurs, it cannot provide timely protection.

[0025] The natural gas engine jet drive protection circuit proposed in this embodiment has a fast response speed, and realizes reliable, effective and fast overcurrent protection for the natural gas engine jet drive device. It also has a simple structure, small size and low cost, and is suitable for popularization and application.

[0026] Example 2

[0027] Please refer to Figure 2 As stated, Figure 2 This is a structural diagram of the natural gas engine jet drive device provided in Example 2 of the present invention. As shown in the figure, the natural gas engine jet drive device in this embodiment includes a high-side drive power circuit, a low-side drive power circuit, a jet drive control chip T1, and the natural gas engine jet drive protection circuit described in Example 1 above.

[0028] 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 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 to ground.

[0029] 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.

[0030] Exemplarily, the low-side drive power circuit includes a transistor Q4 ; a gate of the transistor Q4 is connected to the ejection drive control chip T1 , and a drain of the transistor Q4 is connected to one end of a resistor R1 and a control end of a controllable switch Q1 .

[0031] Exemplarily, the natural gas engine injection drive device 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.

[0032] In this embodiment, the drive 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.

[0033] In this embodiment, the controllable switch Q1 is, 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. In this embodiment, the transistors Q2, Q3, and Q4 are, but are not limited to, insulated gate field-effect transistors.

[0034] Specifically, when an overcurrent occurs in the drive circuit of a natural gas engine jet drive device, a voltage is generated on the resistor R1, which controls the on and off of the controllable switch Q1. Taking the controllable switch Q1 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. When 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.

[0035] Compared to conventional solutions that incorporate a current sampling resistor in series with the low-side driver of a natural gas engine jet drive device, which collects the voltage across the resistor and transmits it to the jet control chip, which then determines whether an overcurrent fault has occurred in the drive circuit and outputs a control signal to the jet drive control chip to implement overcurrent protection, the natural gas engine jet drive protection circuit in this embodiment directly shuts down the high-side and low-side driver power circuits when the drive circuit experiences an overcurrent. This significantly reduces the transmission path and protection delay, and effectively avoids the problems of conventional solutions that, in the event of an overcurrent fault, result in overheating and damage to the series resistor due to increased current, as well as the cost increase associated with the need for multiple current transformers in parallel to reduce power consumption. Compared to conventional current transformer solutions, the natural gas engine jet drive protection circuit in this embodiment also addresses the shortcomings of conventional current transformer overcurrent protection solutions, offering a fast response speed and reliable, effective, and rapid overcurrent protection for the natural gas engine jet drive device. Furthermore, it features a simple structure, compact size, and low cost. The traditional current transformer solution uses 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 that is input to the jet main control chip for overcurrent protection. This solution couples an auxiliary winding with the load coil to form a current transformer to collect the load current. After signal processing, the collected signal is sent to the jet drive control chip for judgment. However, implementing this solution requires adding an auxiliary coil to function as a current transformer, which is complex and increases product size and cost. Moreover, the current transformer's response time for current coupling is slow, and when a high current short circuit occurs, it cannot provide timely protection.

[0036] Specifically, the driving current sampling circuit in the natural gas engine injection drive device proposed in this embodiment samples the injection current through the resistor R4. 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 transistors Q2 and Q3 of the high-side drive power circuit and the transistor Q4 of the low-side drive power circuit to complete the control and regulation of the injection current. This effectively solves the problem of the traditional solution of a low-side drive series current sampling resistor in the natural gas engine injection drive device, where the voltage is collected from the low-side drive sampling resistor and then input to the injection main control chip T2, with a long signal loop and easy signal interference. The signal loop is short and the interference is small, so the output current value can be accurately and stably controlled to change with the load, and is suitable for promotion and application.

[0037] Note that the above are merely preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will appreciate that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions are possible for those skilled in the art without departing from the scope of protection of the present invention. Therefore, while the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the scope of the present invention. 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, 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 is, but 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 jet drive device, 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 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 to ground.

4. The natural gas engine jet drive device 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 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.

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

6. The natural gas engine jet drive device 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 jet drive device according to claim 6, characterized in that: The controllable switch Q1 is, but 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 jet drive device 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.

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