Measuring circuit, electronic control fuel injector and driving pulse width measuring method of electronic control fuel injector

Abstract

The invention provides a measuring circuit, an electronic control fuel injector and a driving pulse width measuring method of the electronic control fuel injector. The measuring circuit comprises a detection circuit connected to a fuel injector driving circuit in parallel. The detection circuit comprises a first branch circuit and a second branch circuit which are connected with the fuel injector driving circuit in parallel, the first branch circuit is provided with a first group of control elements, and the second branch circuit is provided with a second group of control elements; the detection circuit further comprises a receiving circuit, and the receiving circuit is used for receiving a detection signal sent by the first branch circuit or the second branch circuit when the fuel injector is turned on or turned off so as to calculate the driving pulse width of the fuel injector. According to the measuring circuit, no matter whether the fuel injector is turned on or turned off, the first branch circuit or the second branch circuit sends signals to the receiving circuit, the receiving circuit can effectively detect the turning-on and turning-off moments of the fuel injector through the detection signals, voltage and current signals driven by the fuel injector do not need to be analyzed in real time, the calculation workload of software is greatly reduced, and the working efficiency is improved. And a lot of software resources are saved.

Description

Technical Field

[0001] The invention relates to the technical field of pulse width measurement of electronically controlled fuel injectors, and in particular to a measurement circuit, an electronically controlled fuel injector and a driving pulse width measurement method. Background Art

[0002] For the injector, online measurement of the injector drive pulse width can be used not only to calculate the actual injection amount, but also to calculate the injector opening delay, etc., which is of great significance to the working status of the injector.

[0003] At present, there are two main types of traditional methods for measuring the actual injector drive pulse width:

[0004] The first type relies on the controller's internal sampling resistor (or external current Hall sensor) to collect the injector current value, and performs data analysis on the collected current value to obtain the actual drive pulse width of the injector. The advantage of the first type of measurement method is that it can directly calculate the actual opening and closing time of the injector by performing algorithm analysis on the collected injector current value. The disadvantage is that since the algorithm is used to calculate the injector current data in real time, the software calculation workload is large, which greatly increases the software usage resources, and the injector current is easily affected by external interference, which can easily lead to misjudgment of the software calculation results.

[0005] The second type mainly relies on collecting the voltage at both ends of the injector (or the power supply voltage that drives the injector), and performing data analysis on the collected voltage value to obtain the actual driving pulse width of the injector. The advantage of the second type of method is that it can directly calculate the actual opening and closing time of the injector by performing algorithm analysis on the collected voltage at both ends of the injector load coil. However, since the algorithm is used to calculate the voltage data at both ends of the injector load coil in real time, the software calculation workload is large, which greatly increases the software usage resources, and the injector load coil is susceptible to external interference, which is easy to misjudge the software calculation results.

[0006] Both of the above measurement methods use software algorithms (calculating the multi-order derivatives of voltage and current at different times for analysis) to analyze the voltage across the injector load coil and the injector drive current data, thereby obtaining the actual opening and closing times of the injector.

[0007] This results in a large amount of calculations during the measurement process, poor accuracy of the calculation results, and easy misjudgment.

[0008] Based on this, the inventor of the present application proposes a measurement circuit, an electronically controlled fuel injector and a drive pulse width measurement method in order to solve the above technical problems. Summary of the invention

[0009] The technical problem to be solved by the present invention is to overcome the defects of large amount of calculation, poor calculation result accuracy and easy misjudgment in the pulse width measurement process in the prior art, and provide a measurement circuit, an electronically controlled fuel injector and a driving pulse width measurement method.

[0010] The present invention solves the above technical problems through the following technical solutions:

[0011] The present invention provides a measuring circuit, which is characterized in that it is used for measuring pulse width of a fuel injector, and the measuring circuit comprises:

[0012] A detection circuit connected in parallel to the injector drive circuit;

[0013] The detection circuit comprises a first branch and a second branch connected in parallel with the injector drive circuit, the first branch is provided with a first group of control elements, and the second branch is provided with a second group of control elements;

[0014] The detection circuit also includes a receiving circuit, which is used to receive a detection signal sent by the first branch or the second branch when the injector is turned on or off, so as to calculate a driving pulse width of the injector.

[0015] According to one embodiment of the present invention, the first group of control elements are first light emitting diodes, and the second group of control elements are second light emitting diodes;

[0016] The first branch is also provided with a first resistor, which is connected in series with the anode of the first light-emitting diode; the second branch is also provided with a second resistor, which is connected in series with the cathode of the second light-emitting diode; wherein,

[0017] The detection signal is an optical signal. The receiving circuit is provided with an optical signal receiving device, and the optical signal receiving device is used to convert the optical signal into a pulse signal.

[0018] According to an embodiment of the present invention, the first resistor and the second resistor are current limiting resistors.

[0019] According to one embodiment of the present invention, one end of the receiving circuit is connected to the MCU, and the other end is grounded;

[0020] When the injector coil of the injector driving circuit is driven, the first branch is connected, the first light emitting diode is turned on to send a light signal to the light signal receiving device, and the light signal receiving device converts the light signal into a pulse signal and outputs it to the MCU;

[0021] When the injector coil of the injector driving circuit is turned off, the second branch is connected, the second light emitting diode is turned on to emit a light signal to the light signal receiving device, and the light signal receiving device converts the light signal into a pulse signal and outputs it to the MCU.

[0022] According to one embodiment of the present invention, the first branch includes a first branch circuit and a second branch circuit connected in parallel;

[0023] The first branch circuit is provided with a third light emitting diode and a fourth light emitting diode which are reversely connected in series, the second branch circuit is provided with a fifth light emitting diode and a sixth light emitting diode which are reversely connected in series, the anode of the third light emitting diode is connected to the positive anode terminal of the injector drive circuit, and the cathode of the fifth light emitting diode is connected to the positive anode terminal of the injector drive circuit;

[0024] One end of the second branch is connected between the third light emitting diode and the fourth light emitting diode, and the other end is connected between the fifth light emitting diode and the sixth light emitting diode;

[0025] The first group of control elements includes the third light emitting diode, the fourth light emitting diode, the fifth light emitting diode and the sixth light emitting diode;

[0026] The second set of control elements includes a seventh light emitting diode;

[0027] The detection signal is an optical signal. The receiving circuit is provided with an optical signal receiving device, and the optical signal receiving device is used to convert the optical signal into a pulse signal.

[0028] According to an embodiment of the present invention, the second group of control elements further includes a third resistor, and the third resistor is connected to the anode of the seventh light emitting diode.

[0029] According to an embodiment of the present invention, the third resistor is a current limiting resistor.

[0030] According to an embodiment of the present invention, the seventh light emitting diode transmits the optical signal to the optical signal receiving device through an optical fiber, and one end of the receiving circuit is connected to the MCU and the other end is grounded;

[0031] When the injector coil of the injector driving circuit is driven, the third light emitting diode and the sixth light emitting diode are turned on so that the seventh light emitting diode is turned on to send a light signal to the light signal receiving device, and the light signal receiving device converts the light signal into a pulse signal and outputs it to the MCU;

[0032] When the injector coil of the injector driving circuit is turned off, the fourth light emitting diode and the fifth light emitting diode are turned on so that the seventh light emitting diode is turned on to emit a light signal to the light signal receiving device, and the light signal receiving device converts the light signal into a pulse signal and outputs it to the MCU.

[0033] The present invention also provides an electronically controlled fuel injector, comprising:

[0034] A fuel injector driving circuit, wherein the fuel injector coil is arranged on the fuel injector driving circuit;

[0035] The measuring circuit as described above is used to detect the injector driving pulse width.

[0036] The present invention also provides a method for measuring the driving pulse width of an electronically controlled fuel injector, which is implemented by using the measurement circuit or the electronically controlled fuel injector as described above, and the measurement method comprises:

[0037] Get the detection signal;

[0038] The response delay and driving pulse width of the injector are calculated according to the detection signal.

[0039] The positive and progressive effects of the present invention are:

[0040] In the measuring circuit of the present invention, no matter whether the fuel injector is turned on or off, the first branch or the second branch sends a signal to the receiving circuit, and the receiving circuit can effectively detect the opening and closing moments of the fuel injector by detecting the signal. In this way, there is no need to analyze the voltage and current signals driven by the fuel injector in real time, which greatly reduces the calculation workload of the software and saves a lot of software resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0042] Figure 1 is a schematic diagram of an embodiment of a measuring circuit of the present invention;

[0043] Figure 2 FIG. 4 is a schematic diagram of another embodiment of the measuring circuit of the present invention.

[0044] 1. Detection circuit;

[0045] 2. first branch circuit; 21. first light emitting diode; 22. first resistor; 23. first branch circuit; 231. third light emitting diode; 232. fourth light emitting diode; 24. second branch circuit; 241. fifth light emitting diode; 242. sixth light emitting diode;

[0046] 3. Second branch; 31. Second light emitting diode; 32. Second resistor; 33. Seventh light emitting diode; 34. Third resistor;

[0047] 4. Receiving circuit; 41. Optical signal receiving device;

[0048] 5. Injector drive circuit. DETAILED DESCRIPTION

[0049] The present invention is further described below in conjunction with specific embodiments and drawings. More details are elaborated in the following description to facilitate a full understanding of the present invention. However, the present invention can obviously be implemented in a variety of other ways different from the description herein. Those skilled in the art can make similar generalizations and deductions based on actual application situations without violating the connotation of the present invention. Therefore, the protection scope of the present invention should not be limited by the content of this specific embodiment.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0051] Please refer to Figure 1 and Figure 2 The present invention proposes a measuring circuit for measuring the pulse width of an injector, the measuring circuit comprising: a detection circuit 1 connected in parallel to a drive circuit 5 of the injector; the detection circuit 1 comprises a first branch 2 and a second branch 3 connected in parallel to the drive circuit 5 of the injector, the first branch 2 is provided with a first group of control elements, and the second branch 3 is provided with a second group of control elements.

[0052] The detection circuit 1 further comprises a receiving circuit 4, which is used to receive a detection signal sent by the first branch 2 or the second branch 3 when the fuel injector is turned on or off, so as to calculate a driving pulse width of the fuel injector.

[0053] It can be seen that no matter whether the injector is turned on or off, the first branch 2 or the second branch 3 has a detectable signal sent to the receiving circuit 4. The receiving circuit 4 can effectively detect the opening and closing moments of the injector by detecting the signal. In this way, there is no need to analyze the voltage and current signals driven by the injector in real time, which greatly reduces the calculation workload of the software and saves a lot of software resources.

[0054] Please refer to Figure 1The first group of control elements is a first light-emitting diode 21, and the second group of control elements is a second light-emitting diode 31; the first branch 2 is also provided with a first resistor 22, and the first resistor 22 is connected in series with the anode of the first light-emitting diode 21, and the second branch 3 is also provided with a second resistor 32, and the second resistor 32 is connected in series with the cathode of the second light-emitting diode 31; wherein the detection signal is an optical signal, and the receiving circuit 4 is provided with an optical signal receiving device 41, and the optical signal receiving device 41 is used to convert the optical signal into a pulse signal.

[0055] The first resistor 22 and the second resistor 32 are current limiting resistors.

[0056] Furthermore, one end of the receiving circuit 4 is connected to the MCU, and the other end is grounded.

[0057] Reference Figure 1 It can be seen that the first resistor 22 is connected in series with the anode of the first light emitting diode 21 and is connected at both ends of the A / B point. The second resistor 32 is connected in series with the anode of the second light emitting diode 31 and is connected at both ends of the A / B point.

[0058] The optical signals emitted by the first light emitting diode 21 and the second light emitting diode 31 are input to the optical signal receiving device 41 through the optical fiber, and the optical signal receiving device 41 converts the optical signals into pulse signals and outputs them to the MCU.

[0059] The first resistor 22 and the second resistor 32 are current limiting resistors, which control the current flowing through the first LED 21 and the second LED 31 , and further control the light intensity of the first LED 21 and the second LED 31 .

[0060] According to the voltage across the injector when it is turned on, the back electromotive force voltage across the injector when it is turned off, and the rated photocurrent of the light emitting diode, a suitable first resistor 22 and second resistor 32 can be selected to ensure that the light emitting diode can work normally.

[0061] The measuring principle of the measuring circuit is explained as follows:

[0062] When the injector coil of the injector driving circuit 5 is driven, Va>Vb, the first light emitting diode 21 is turned on, the first light emitting diode 21 sends a light signal to the light signal receiving device 41, and the light signal receiving device 41 converts the light signal into a pulse signal and outputs it to the MCU;

[0063] When the injector coil of the injector driving circuit 5 is turned off, a back electromotive force appears at both ends of the injector coil. At this time, Vb>Va, the second light-emitting diode 31 is turned on and sends a light signal to the light signal receiving device 41, and the light signal receiving device 41 converts the light signal into a pulse signal and outputs it to the MCU.

[0064] Reference Figure 2The first branch 2 includes a first branch circuit 23 and a second branch circuit 24 connected in parallel; the first branch circuit 23 is provided with a third light emitting diode 231 and a fourth light emitting diode 232 connected in reverse series, the second branch circuit 24 is provided with a fifth light emitting diode 241 and a sixth light emitting diode 242 connected in reverse series, the anode of the third light emitting diode 231 is connected to the positive anode end of the injector drive circuit 5, and the cathode of the fifth light emitting diode 241 is connected to the positive anode end of the injector drive circuit 5. One end of the second branch 3 is connected between the third light emitting diode 231 and the fourth light emitting diode 232, and the other end is connected between the fifth light emitting diode 241 and the sixth light emitting diode 242; the first group of control elements includes the third light emitting diode 231, the fourth light emitting diode 232, the fifth light emitting diode 241 and the sixth light emitting diode 242; the second group of control elements includes the seventh light emitting diode 33; the detection signal is an optical signal, and the receiving circuit 4 is provided with an optical signal receiving device 41, which is used to convert the optical signal into a pulse signal.

[0065] Specifically, the second group of control elements further includes a third resistor 34, and the third resistor 34 is connected to the anode of the seventh light-emitting diode 33. Optionally, the third resistor 34 is a current-limiting resistor.

[0066] The seventh light emitting diode 33 transmits the optical signal to the optical signal receiving device 41 through the optical fiber. One end of the receiving circuit 4 is connected to the MCU, and the other end is grounded.

[0067] Reference Figure 2 The third light emitting diode 231, the fourth light emitting diode 232, the fifth light emitting diode 241, the sixth light emitting diode 242 and the seventh light emitting diode 33 form a rectifier bridge, the A / C points of the rectifier bridge are connected to the two ends of the injector respectively, the B point is connected to the third resistor 34, the D point is connected to the cathode of the seventh light emitting diode 33, and the third resistor 34 is connected to the anode of the seventh light emitting diode 33. The optical signal emitted by the seventh light emitting diode 33 is transmitted to the optical signal receiving device 41 through the optical fiber line, and the optical signal receiving device 41 converts the optical signal into a pulse signal and outputs it to the MCU.

[0068] The third resistor 34 is a current limiting resistor, so that the current flowing through the seventh light emitting diode 33 can be controlled, thereby controlling the light intensity of the seventh light emitting diode 33 .

[0069] That is, according to the voltage across the two ends when the injector is turned on, the back electromotive force voltage across the two ends when the injector is turned off, and the rated photocurrent of the light emitting diode, a suitable third resistor 34 can be selected to ensure that the seventh light emitting diode 33 can operate normally.

[0070] The measuring principle of the measuring circuit is explained as follows:

[0071] When the injector coil is driven, Va>Vc in the rectifier bridge circuit, at this time Vb>Vd, and the current sequentially flows through the third light emitting diode 231, the third resistor 34, the seventh light emitting diode 33 and the sixth light emitting diode 242. The seventh light emitting diode 33 sends an optical signal to the optical signal receiving device 41, and the optical signal receiving device 41 converts the optical signal into a pulse signal and outputs it to the MCU.

[0072] When the injector coil is turned off, back electromotive force appears at both ends of the injector coil. At this time, Vc>Va, Vb>Vd, and the current flows through the fourth light-emitting diode 232, the third resistor 34, the seventh light-emitting diode 33 and the fifth light-emitting diode 241 in sequence. The seventh light-emitting diode 33 sends a light signal to the light signal receiving device 41, and the light signal receiving device 41 converts the light signal into a pulse signal and outputs it to the MCU.

[0073] No matter the injector is turned on or off, the seventh light emitting diode 33 is turned on, so as to send a light signal to the light signal receiving device 41 .

[0074] In summary, the measuring circuit proposed in the present invention is composed of a plurality of light emitting diodes, a current limiting resistor and an optical signal receiver, and has a simple structure and low design cost.

[0075] Whether the injector is turned on or off, a light signal is transmitted to the light signal receiver, and the light signal is converted into a pulse signal by the light signal receiver, so as to effectively detect the opening and closing moments of the injector.

[0076] Based on this, the time difference between the opening and closing moments of the injector can be used to accurately calculate the drive pulse width of the injector, thereby accurately calculating the cyclic injection amount of the injector.

[0077] The pulse signal is used to calculate the opening and closing time of the injector, without the need to analyze the voltage and current signals driven by the injector in real time, which greatly reduces the calculation workload of the software and saves a lot of software resources.

[0078] Moreover, for long-distance use, signal transmission is carried out using optical fiber lines, which can greatly improve signal transmission quality and reduce unnecessary signal interference.

[0079] The present invention further provides an electronically controlled fuel injector, comprising a fuel injector drive circuit 5 and the above-mentioned measuring circuit, wherein the fuel injector coil is arranged on the fuel injector drive circuit 5; and the measuring circuit is used to detect the fuel injector drive pulse width.

[0080] Optionally, the fuel injector driving circuit 5 drives the fuel injector in a half-bridge mode, and a control signal is sent by a single chip microcomputer to control the power device to drive the fuel injector load.

[0081] The measuring circuit is used to collect the voltage across the injector, drive the light-emitting diode, and then convert the on and off times of the injector drive into pulse signals through photoelectric conversion and input them into the microcontroller, thereby calculating the actual drive pulse width of the injector.

[0082] The present invention also provides a method for measuring the driving pulse width of an electronically controlled fuel injector, which is implemented by using the above measurement circuit or electronically controlled fuel injector. The measurement method includes:

[0083] Get the detection signal;

[0084] The response delay and driving pulse width of the injector are calculated based on the detection signal.

[0085] The measuring method of the present invention can accurately measure the opening and closing time of the fuel injector, and further can accurately calculate the response delay and driving pulse width of the fuel injector.

[0086] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "install", "connect", "connect", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can also be a mechanical connection. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0087] The present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or multiple times in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0088] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A measuring circuit, characterized in that: Used for measuring pulse width of fuel injector, the measuring circuit comprises: A detection circuit connected in parallel to the injector drive circuit; The detection circuit comprises a first branch and a second branch connected in parallel with the injector drive circuit, the first branch is provided with a first group of control elements, and the second branch is provided with a second group of control elements; The detection circuit also includes a receiving circuit, which is used to receive a detection signal sent by the first branch or the second branch when the injector is turned on or off, so as to calculate a driving pulse width of the injector.

2. The measuring circuit according to claim 1, characterized in that: The first group of control elements are first light emitting diodes, and the second group of control elements are second light emitting diodes; The first branch is also provided with a first resistor, which is connected in series with the anode of the first light-emitting diode; the second branch is also provided with a second resistor, which is connected in series with the cathode of the second light-emitting diode; wherein, The detection signal is an optical signal. The receiving circuit is provided with an optical signal receiving device, and the optical signal receiving device is used to convert the optical signal into a pulse signal.

3. The measuring circuit according to claim 2, characterized in that: The first resistor and the second resistor are current limiting resistors.

4. The measuring circuit according to claim 2, characterized in that: One end of the receiving circuit is connected to the MCU, and the other end is grounded; When the injector coil of the injector driving circuit is driven, the first branch is connected, the first light emitting diode is turned on to send a light signal to the light signal receiving device, and the light signal receiving device converts the light signal into a pulse signal and outputs it to the MCU; When the injector coil of the injector driving circuit is turned off, the second branch is connected, the second light emitting diode is turned on to emit a light signal to the light signal receiving device, and the light signal receiving device converts the light signal into a pulse signal and outputs it to the MCU.

5. The measuring circuit according to claim 1, characterized in that: The first branch includes a first branch circuit and a second branch circuit connected in parallel; The first branch circuit is provided with a third light emitting diode and a fourth light emitting diode which are reversely connected in series, the second branch circuit is provided with a fifth light emitting diode and a sixth light emitting diode which are reversely connected in series, the anode of the third light emitting diode is connected to the positive anode terminal of the injector drive circuit, and the cathode of the fifth light emitting diode is connected to the positive anode terminal of the injector drive circuit; One end of the second branch is connected between the third light emitting diode and the fourth light emitting diode, and the other end is connected between the fifth light emitting diode and the sixth light emitting diode; The first group of control elements includes the third light emitting diode, the fourth light emitting diode, the fifth light emitting diode and the sixth light emitting diode; The second set of control elements includes a seventh light emitting diode; The detection signal is an optical signal. The receiving circuit is provided with an optical signal receiving device, and the optical signal receiving device is used to convert the optical signal into a pulse signal.

6. The measuring circuit according to claim 5, characterized in that: The second group of control elements further includes a third resistor, and the third resistor is connected to the anode of the seventh light emitting diode.

7. The measuring circuit according to claim 6, characterized in that: The third resistor is a current limiting resistor.

8. The measuring circuit according to claim 5, characterized in that: The seventh light emitting diode transmits the optical signal to the optical signal receiving device through the optical fiber, one end of the receiving circuit is connected to the MCU, and the other end is grounded; When the injector coil of the injector driving circuit is driven, the third light emitting diode and the sixth light emitting diode are turned on so that the seventh light emitting diode is turned on to send a light signal to the light signal receiving device, and the light signal receiving device converts the light signal into a pulse signal and outputs it to the MCU; When the injector coil of the injector driving circuit is turned off, the fourth light emitting diode and the fifth light emitting diode are turned on so that the seventh light emitting diode is turned on to emit a light signal to the light signal receiving device, and the light signal receiving device converts the light signal into a pulse signal and outputs it to the MCU.

9. An electronically controlled fuel injector, characterized in that: include: A fuel injector driving circuit, wherein the fuel injector coil is arranged on the fuel injector driving circuit; The measurement circuit according to any one of claims 1 to 8, wherein the measurement circuit is used to detect the injector drive pulse width.

10. A method for measuring the pulse width of an electronically controlled fuel injector drive, characterized in that: The measuring method is implemented by using the measuring circuit according to any one of claims 1 to 8 or the electronically controlled fuel injector according to claim 9, wherein the measuring method comprises: Get the detection signal; The response delay and driving pulse width of the injector are calculated according to the detection signal.

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