A wide-range oxygen sensor controller

Abstract

A wide-band oxygen sensor controller includes a processing unit, a pump current control unit, a Nernst control unit, a heating circuit, and a power supply. The controlled wide-band oxygen sensor includes a calibration resistor, a current pump, a reference pump, and a heater resistor, which are connected in series. The pump current control unit connects the two ends of the calibration resistor via a sampling resistor electrode and a pump current electrode. The Nernst control unit connects the two ends of the reference pump via a Nernst electrode and a common electrode. The heating circuit connects the two ends of the heater resistor via a heating positive electrode and a heating negative electrode. The processing unit samples and calculates the Nernst voltage, pump voltage, power supply voltage, common electrode voltage, and pump current voltage to control the current pump, adjust the pump current to achieve Nernst voltage regulation, and control the heating circuit to perform heating. This wide-band oxygen sensor controller is highly versatile, and sensor performance is judged by internal sensor parameter output, resulting in accurate control and wide applicability.

Description

Technical Field

[0001] The present invention relates to gas detection technology, and in particular to a wide-range oxygen sensor controller. Background Art

[0002] Wide-range oxygen sensors measure the oxygen content in automotive exhaust gases and are used to monitor the efficiency of the combustion process in automotive engines. By measuring and adjusting the air / fuel mixture, they aim to achieve the best possible fuel economy and the lowest possible exhaust emissions. Wide-range oxygen sensors control two regulation loops: one for temperature control and the other for electrochemical pumping control. Wide-range oxygen sensors are passive devices encapsulated with a zirconia ceramic chip. In practical applications, they require the vehicle control unit (ECU) to drive them via a dedicated control chip. Both production and measurement equipment utilize dedicated ECU control chips for control and measurement. However, due to the fixed control strategies and parameter outputs of these dedicated chips, they cannot accurately determine sensor status and performance during operation. Furthermore, the controller chips for wide-range oxygen sensors vary from manufacturer to manufacturer. A versatile wide-range oxygen sensor controller is needed that can accurately determine sensor status and performance during operation.

[0003] It should be noted that the information disclosed in the above background technology section is only used to understand the background of this application, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0004] The main purpose of the present invention is to overcome the defects of the above-mentioned background technology and provide a wide-range oxygen sensor controller.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A wide-range oxygen sensor controller includes a processing unit, a pump current control unit, a Nernst control unit, a heating circuit, and a power supply. The processing unit is connected to the pump current control unit, the Nernst control unit, and the heating circuit, respectively. The pump current control unit, the Nernst control unit, and the heating circuit are connected to a wide-range oxygen sensor. The wide-range oxygen sensor includes a calibration resistor, a current pump, a reference pump, and a heater resistor. The calibration resistor, the current pump, and the reference pump are connected in series in sequence. The pump current control unit is connected to both ends of the calibration resistor via a sampling resistor electrode and a pump current electrode. The Nernst control unit is connected to both ends of the reference pump via a Nernst electrode and a common electrode. The heating circuit is connected to both ends of the heater resistor via a heating positive electrode and a heating negative electrode. The processing unit samples and calculates the Nernst voltage, pump voltage, power supply voltage, common electrode voltage, and pump current voltage to control the current pump, adjust the pump current to achieve Nernst voltage regulation, and control the heating circuit to perform heating.

[0007] Further:

[0008] The current pump and the heating circuit are controlled by PWM control.

[0009] It also includes a connector, which has positive and negative electrode pins of the heating resistor, a common electrode pin, a Nernst electrode pin, a sampling resistor electrode pin and a pump current electrode pin. The pump current control unit, the Nernst control unit and the heating circuit are connected to the calibration resistor, current pump, reference pump and heater resistor of the wide-range oxygen sensor through the corresponding pins of the connector.

[0010] The heating circuit includes a first electronic switching tube, a first sampling resistor, and a first amplifier. The first electronic switching tube, the first sampling resistor, and the heater resistor are connected in series. Two input ends of the first amplifier are connected to two ends of the first sampling resistor, and the output end of the first amplifier is connected to the processing unit. The processing unit is connected to a driving end of the first electronic switching tube. The voltage across the first sampling resistor is amplified by the first amplifier and sampled by the processing unit. The processing unit calculates the current on the first sampling resistor based on the sampling signal and outputs a PWM control signal to drive the first electronic switching tube, thereby controlling the on / off state of the circuit of the heater resistor to control heating and enable the wide-band oxygen sensor to reach a normal operating temperature.

[0011] Heating control adopts PID regulation.

[0012] The pump current control unit includes a PWM-controlled constant current source, a second sampling resistor, and a second amplifier. The second sampling resistor is connected in parallel with the calibration resistor and then connected in series with the PWM-controlled constant current source. The processing unit is connected to the PWM-controlled constant current source, the two input ends of the second amplifier are connected to the two ends of the second sampling resistor, and the output end of the second amplifier is connected to the processing unit. The voltage across the second sampling resistor is amplified by the second amplifier and sampled by the processing unit. The processing unit calculates the current flowing through the second sampling resistor based on the sampling signal and adjusts the pump current through the PWM-controlled constant current source.

[0013] The Nernst control unit includes a third amplifier, a second electronic switch tube and a second current source. The two input ends of the third amplifier are connected to the two ends of the reference pump through the Nernst electrode and the common electrode respectively. The end of the third amplifier connected to the Nernst electrode is connected to the power supply through the second current source and the second electronic switch tube in sequence, and the other end of the second electronic switch tube is connected to the power supply. The voltages at the two input ends of the third amplifier are amplified by the second amplifier and sampled by the processing unit. The processing unit calculates the Nernst voltage based on the sampling signal. The processing unit controls the on and off of the second electronic switch and controls the opening of the second current source. The internal resistance of the reference pump is calculated based on the difference between the Nernst voltages before and after opening and the current of the second current source. The internal resistance of the reference pump is adjusted to a set target value by adjusting the heating circuit, and the Nernst voltage is adjusted to a set target value by adjusting the pump current.

[0014] The common electrode is connected to a 2V DC power supply.

[0015] It also includes a communication circuit, the processing unit is connected to the communication circuit, and the processing unit exchanges data with the host computer through the communication circuit, and the data includes control parameters.

[0016] The communication circuit is an RS232 serial communication circuit.

[0017] The present invention provides a wide-range oxygen sensor controller with good versatility, which can be used to control wide-range oxygen sensors from different manufacturers. During operation, the controller can judge the working status and performance of the sensor, thereby achieving precise control of the sensor. The controller has strong versatility, judges the sensor performance through the output of the sensor's internal parameters, and has accurate and stable control and wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic structural diagram of a wide-range oxygen sensor controller according to an embodiment of the present invention.

[0019] Figure 2This is a schematic structural diagram of a wide-range oxygen sensor according to an embodiment of the present invention.

[0020] Figure 3 The figure is a schematic structural diagram of a heating circuit according to an embodiment of the present invention.

[0021] Figure 4 This is a schematic structural diagram of a pump current control unit according to an embodiment of the present invention.

[0022] Figure 5 The figure is a schematic structural diagram of a Nernst control unit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope of the present invention and its application.

[0024] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for both fixing and coupling or communication.

[0025] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0027] See Figure 1 and Figure 2An embodiment of the present invention provides a wide-range oxygen sensor controller 1, comprising a processing unit 4 (e.g., a single-chip microcomputer MCU), a pump current control unit 5, a Nernst control unit 6, a heating circuit 7, and a switching power supply 8. The processing unit 4 is connected to the pump current control unit 5, the Nernst control unit 6, and the heating circuit 7, respectively. The pump current control unit 5, the Nernst control unit 6, and the heating circuit 7 are connected to a controlled wide-range oxygen sensor 2. The wide-range oxygen sensor 2 comprises a calibration resistor 11, a current pump 12, a reference pump 13, and a heater resistor 14. The calibration resistor 11, the current pump 12, and the reference pump 13 are sequentially connected in series. The pump current control unit 5, the Nernst control unit 6, and the heating circuit 7 are connected to a controlled wide-range oxygen sensor 2. The control unit 5 is connected to the two ends of the calibration resistor 11 through the sampling resistor electrode and the pump current electrode, the Nernst control unit 6 is connected to the two ends of the reference pump 13 through the Nernst electrode and the common electrode, and the heating circuit 7 is connected to the two ends of the heater resistor 14 through the heating positive electrode and the heating negative electrode; the external power supply 3 supplies power to the switching power supply 8, and the switching power supply 8 supplies power to each power unit of the controller, wherein the processing unit 4 controls the current pump 12 by sampling and calculating the Nernst voltage, pump voltage, power supply voltage, common electrode voltage, and pump current voltage, adjusts the pump current to achieve Nernst voltage regulation, and controls the heating circuit 7 to heat to achieve the required working temperature.

[0028] like Figure 1 As shown, in a preferred embodiment, the wide-band oxygen sensor controller 1 further includes a communication circuit 9, the processing unit 4 is connected to the communication circuit 9, and the processing unit 4 exchanges data with the host computer 10 through the communication circuit 9, wherein the data includes control parameters. In some embodiments, the communication circuit 9 is an RS232 serial communication circuit.

[0029] In a preferred embodiment of the present invention, the current pump 12 and the heating circuit 7 are controlled by PWM control.

[0030] In some embodiments, the wide-range oxygen sensor controller 1 further includes a connector (not shown), which has positive and negative electrode pins of a heating resistor, a common electrode pin, a Nernst electrode pin, a sampling resistor electrode pin, and a pump current electrode pin. The pump current control unit 5, the Nernst control unit 6, and the heating circuit 7 are connected to the calibration resistor 11, the current pump 12, the reference pump 13, and the heater resistor 14 of the wide-range oxygen sensor 2 via the corresponding pins through the connector.

[0031] like Figure 3As shown, in a preferred embodiment, the heating circuit 7 includes a first electronic switch tube 15, a first sampling resistor 16 and a first amplifier 17. The first electronic switch tube 15, the first sampling resistor 16 and the heater resistor 14 are connected in series. The two input ends of the first amplifier 17 are connected to the two ends of the first sampling resistor 16, and the output end of the first amplifier 17 is connected to the processing unit 4. The processing unit 4 is connected to the driving end of the first electronic switch tube 15. The voltage across the first sampling resistor 16 is amplified by the first amplifier 17 and sampled by the processing unit 4. The processing unit 4 calculates the current on the first sampling resistor 16 based on the sampling signal and outputs a PWM control signal to drive the first electronic switch tube 15, thereby controlling the on / off of the circuit of the heater resistor 14 to control heating, so that the wide-band oxygen sensor 2 reaches the normal operating temperature.

[0032] In a preferred embodiment, the heating control adopts PID regulation. In a preferred embodiment, the heating circuit 7 provides a 12V voltage to the heater resistor 14.

[0033] like Figure 4 As shown, in a preferred embodiment, the pump current control unit 5 includes a PWM-controlled constant current source 20, a second sampling resistor 18 and a second amplifier 19. The second sampling resistor 18 is connected in parallel with the calibration resistor 11 and then connected in series with the PWM-controlled constant current source 20. The processing unit 4 is connected to the PWM-controlled constant current source 20, and the two input ends of the second amplifier 19 are connected to the two ends of the second sampling resistor 18. The output end of the second amplifier 19 is connected to the processing unit 4. The voltage across the second sampling resistor 18 is amplified by the second amplifier 19 and sampled by the processing unit 4. The processing unit 4 calculates the current flowing through the second sampling resistor 18 according to the sampling signal and adjusts the pump current through the PWM-controlled constant current source 20.

[0034] like Figure 5As shown, in a preferred embodiment, the Nernst control unit 6 includes a third amplifier 23, a second electronic switch tube 21 and a second current source 22. The two input ends of the third amplifier 23 are connected to the two ends of the reference pump 13 through the Nernst electrode and the common electrode respectively. The end of the third amplifier 23 connected to the Nernst electrode is connected to the power supply through the second current source 22 and the second electronic switch tube 21 in sequence. The other end of the second electronic switch tube 21 is connected to the power supply. The voltages at the two input ends of the third amplifier 23 are amplified by the second amplifier and sampled by the processing unit 4. The processing unit 4 calculates the Nernst voltage based on the sampled signal. The processing unit 4 controls the on and off of the second electronic switch and controls the opening of the second current source 22. The internal resistance of the reference pump 13 is calculated based on the difference between the Nernst voltages before and after opening and the current of the second current source 22. The internal resistance of the reference pump 13 is adjusted to a set target value by adjusting the heating circuit 7, and the Nernst voltage is adjusted to a set target value by adjusting the pump current.

[0035] In a preferred embodiment, the common electrode is connected to a 2V DC power supply.

[0036] Embodiments of the present invention provide a versatile wide-range oxygen sensor controller that can be used to control wide-range oxygen sensors of different manufacturers' specifications. During operation, the controller can determine the operating status and performance of the sensor, thereby achieving precise control of the sensor. The controller has strong versatility and can adaptively control the sensor's performance by determining the sensor's internal parameter output, such as closed-loop control. The controller is accurate and stable, and has wide applicability.

[0037] Specific embodiments of the present invention are further described below.

[0038] like Figure 1 As shown, the wide-band oxygen sensor controller 1 includes a single-chip microcomputer (MCU) (processing unit 4), a pump current control unit 5, a Nernst control unit 6, a heating circuit 7, a switching power supply 8, and a communication circuit 9. The wide-band oxygen sensor controller 1 can communicate data with a host computer 10 via a circuit. An external power supply 3 provides power to the controller, and the wide-band oxygen sensor 2 is connected to the controller via contact terminals. The communication circuit 9 is an RS232 serial communication circuit that enables data exchange between the host computer and the single-chip microcomputer. The external power supply 3 supplies power to the controller's switching power supply 8, which then steps down the DC voltage to provide each unit circuit.

[0039] like Figure 2As shown, the wide-range oxygen sensor 2 includes a heater resistor (Rh) 14, a reference pump 13, a current pump 12, and a calibration resistor (Rcal) 11. The wide-range oxygen sensor 2 is connected to the controller through a connector (not shown). The connector has six pins, namely, the positive and negative pins of the heating resistor, the common electrode pin, the Nernst electrode pin, the sampling resistor electrode, and the pump current electrode pin.

[0040] The MCU contains the smallest unit circuit for sampling the Nernst voltage, pump voltage, power supply voltage, common electrode voltage, and pump current voltage. Through sampling and calculation, duty cycle PWM control of the heating circuit is achieved, and the Nernst voltage is regulated by adjusting the pump current circuit. Control parameters are exchanged with the host computer via serial communication.

[0041] like Figure 3 As shown, the heating circuit 7 can control the sensor heater resistor (Rh) 14 to make the sensor reach the normal operating temperature. The single-chip microcomputer MCU outputs a PWM control signal to drive the electronic switch tube 15, so that the 12V voltage applied to the heater resistor (Rh) 14 is turned on, controlling the heater resistor to heat up. The voltage across the current sampling resistor (R1) 16 is amplified by the amplifier 17 and sampled by the MCU. The MCU calculates the current Ih flowing through the heater resistor (Rh) 14, and then

[0042] Rh=12V / Ih-R1.

[0043] During the heating stage, the heating slope and heating power are limited to protect the heating resistor. The heating control adopts PID regulation.

[0044] like Figure 4 In the pump current control unit shown, the controller provides a 2V DC power supply to the common electrode, and the MCU adjusts the pump current Ip through PWM control of the constant current source 20. The voltage across the sampling resistor (R2) 18 is amplified by the amplifier 19 and sampled by the MCU, which calculates the current Ip2 flowing through the sampling resistor (R2) 18.

[0045] like Figure 5 The Nernst control unit shown calculates the Nernst voltage through the voltage difference across the amplifier 20. The MCU controls the electronic switch 21 through a control signal to turn on and off the current source 22. The internal resistance Rv of the reference pump is calculated by the difference ΔV between the Nernst voltage before and after the on-state and the quotient of the current source (Ip3) 22:

[0046] Rv=△V / Ip3.

[0047] The wide-range oxygen sensor is closed-loop controlled. By adjusting the heating circuit, the internal resistance Rv of the reference pump reaches the target value set by the host computer. By adjusting the pump current Ip, the Nernst voltage V reaches the target value set by the host computer, completing the precise control of the wide-range oxygen sensor.

[0048] The background section of the present invention may contain background information about the problem or environment of the present invention, but does not necessarily describe the prior art. Therefore, the inclusion of content in the background section is not an admission by the applicant that the prior art is present.

[0049] The above description further details the present invention in conjunction with specific / preferred embodiments, and the specific implementation of the present invention should not be construed as being limited to these descriptions. Persons skilled in the art will appreciate that, without departing from the spirit of the present invention, they may make various substitutions or modifications to the described embodiments, and these substitutions or modifications should be considered to fall within the scope of protection of the present invention. Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "preferred embodiments," "examples," "specific examples," or "some examples" indicates that the specific features, structures, materials, or characteristics described in conjunction with such embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Persons skilled in the art may combine and assemble the different embodiments or examples described in this specification, as well as features of different embodiments or examples, without conflicting opinions. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications may be made herein without departing from the scope of protection of the patent application.

Claims

1. A wide-range oxygen sensor controller, characterized in that: It includes a processing unit, a pump current control unit, a Nernst control unit, a heating circuit and a power supply. The processing unit is connected to the pump current control unit, the Nernst control unit and the heating circuit respectively. The pump current control unit, the Nernst control unit and the heating circuit are connected to a wide-range oxygen sensor. The wide-range oxygen sensor includes a calibration resistor, a current pump, a reference pump and a heater resistor. The calibration resistor, the current pump and the reference pump are connected in series in sequence. The pump current control unit is connected to both ends of the calibration resistor through a sampling resistor electrode and a pump current electrode. The Nernst control unit is connected to both ends of the reference pump through a Nernst electrode and a common electrode. The heating circuit is connected to both ends of the heater resistor through a heating positive electrode and a heating negative electrode. The processing unit samples and calculates the Nernst voltage, pump voltage, power supply voltage, common electrode voltage and pump current voltage to control the current pump, adjust the pump current to achieve Nernst voltage regulation, and control The heating circuit performs heating; the Nernst control unit includes a third amplifier, a second electronic switch tube and a second current source, the two input ends of the third amplifier are connected to the two ends of the reference pump through the Nernst electrode and the common electrode respectively, the end of the third amplifier connected to the Nernst electrode is connected to the power supply through the second current source and the second electronic switch tube in sequence, and the other end of the second electronic switch tube is connected to the power supply, the voltage of the two input ends of the third amplifier is amplified by the third amplifier and sampled by the processing unit, the processing unit calculates the Nernst voltage based on the sampling signal, the processing unit controls the on and off of the second electronic switch, controls the opening of the second current source, calculates the internal resistance of the reference pump based on the difference between the Nernst voltage before and after opening and the current of the second current source, and adjusts the heating circuit so that the internal resistance of the reference pump reaches the set target value, and adjusts the pump current so that the Nernst voltage reaches the set target value.

2. The wide-band oxygen sensor controller according to claim 1, wherein: The current pump and the heating circuit are controlled by PWM control.

3. The wide-band oxygen sensor controller according to claim 1, wherein: It also includes a connector, which has positive and negative electrode pins of the heating resistor, a common electrode pin, a Nernst electrode pin, a sampling resistor electrode pin and a pump current electrode pin. The pump current control unit, the Nernst control unit and the heating circuit are connected to the calibration resistor, current pump, reference pump and heater resistor of the wide-range oxygen sensor through the corresponding pins of the connector.

4. The wide-band oxygen sensor controller according to any one of claims 1 to 3, wherein: The heating circuit includes a first electronic switching tube, a first sampling resistor, and a first amplifier. The first electronic switching tube, the first sampling resistor, and the heater resistor are connected in series. The two input ends of the first amplifier are connected to the two ends of the first sampling resistor, and the output end of the first amplifier is connected to the processing unit. The processing unit is connected to the driving end of the first electronic switching tube. The voltage across the first sampling resistor is amplified by the first amplifier and sampled by the processing unit. The processing unit calculates the current on the first sampling resistor based on the sampled signal and outputs a PWM control signal to drive the first electronic switching tube, thereby controlling the on / off state of the circuit of the heater resistor to control heating and enable the wide-band oxygen sensor to reach a normal operating temperature.

5. The wide-range oxygen sensor controller according to any one of claims 1 to 3, characterized in that: Heating control adopts PID regulation.

6. The wide-band oxygen sensor controller according to any one of claims 1 to 3, characterized in that: The pump current control unit includes a PWM-controlled constant current source, a second sampling resistor, and a second amplifier. The second sampling resistor is connected in parallel with the calibration resistor and then connected in series with the PWM-controlled constant current source. The processing unit is connected to the PWM-controlled constant current source, the two input ends of the second amplifier are connected to the two ends of the second sampling resistor, and the output end of the second amplifier is connected to the processing unit. The voltage across the second sampling resistor is amplified by the second amplifier and sampled by the processing unit. The processing unit calculates the current flowing through the second sampling resistor based on the sampling signal and adjusts the pump current through the PWM-controlled constant current source.

7. The wide-range oxygen sensor controller according to claim 6, wherein: The common electrode is connected to a 2V DC power supply.

8. The wide-range oxygen sensor controller according to any one of claims 1 to 3, characterized in that: It also includes a communication circuit, the processing unit is connected to the communication circuit, and the processing unit exchanges data with the host computer through the communication circuit, and the data includes control parameters.

9. The wide-range oxygen sensor controller according to claim 8, wherein: The communication circuit is an RS232 serial communication circuit.

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