Oxygen sensor feedback circuit

Abstract

The oxygen sensor feedback circuit comprises a first power supply VDDA1, a resistor R107, a resistor R28, a resistor R109, a resistor R29, a capacitor C25 and a capacitor C26, the first power supply VDDA1 is grounded through the resistor R107 and the resistor R109 in sequence, the common end of the resistor R107 and the common end of the resistor R109 are grounded through the resistor R28 and the capacitor C25 in sequence, and the capacitor C26 is grounded through the resistor R28 and the capacitor C25. The common end of the resistor R28 and the capacitor C25 is electrically connected with an external oxygen sensor, the common end of the resistor R28 and the capacitor C25 is also grounded through the resistor R29 and the capacitor C26 in sequence, and the common end of the resistor R29 and the capacitor C26 is electrically connected with an external EMS (Energy Management System). The output voltage of the oxygen sensor has an increment, and the internal resistance of the oxygen sensor can be calculated according to the increment. The oxygen sensor feedback circuit provided by the utility model has the effect of simultaneously satisfying the wake-up function and the detection function.

Description

Technical Field

[0001] The utility model relates to the technical field of vehicle sensors, in particular to an oxygen sensor feedback circuit. Background Art

[0002] With the normal operation of the engine, the working conditions will change at any time, and there will be large fluctuations in the corresponding exhaust gas temperature and exhaust gas flow, resulting in fluctuations in the heating amount of the sensor by the exhaust gas flow. By monitoring the working conditions, the compensation heat of the heating circuit is adjusted to ensure that the oxygen sensor always operates in a relatively optimal temperature range. In reality, due to the change of the transient working conditions during the operation of the engine, the oxygen sensor is prone to short-term overheating in the actual application of oxygen sensor heating. After long-term accumulation, it is easy to cause damage to the oxygen sensor. In order to achieve precise control of the oxygen sensor temperature and avoid damage to the oxygen sensor, it is necessary to detect the internal resistance of the oxygen sensor and monitor the change of the internal resistance to monitor the target temperature of the oxygen sensor. Summary of the Utility Model

[0003] In view of the above problems, the present invention provides an oxygen sensor feedback circuit to solve the deficiencies in the prior art.

[0004] The specific technical solution is as follows:

[0005] An oxygen sensor feedback circuit includes a first power supply VDDA1, a resistor R107, a resistor R28, a resistor R109, a resistor R29, a capacitor C25, and a capacitor C26. The first power supply VDDA1 is grounded sequentially through the resistor R107 and the resistor R109. The common terminal of the resistor R107 and the resistor R109 is grounded sequentially through the resistor R28 and the capacitor C25. The common terminal of the resistor R28 and the capacitor C25 is electrically connected to an external oxygen sensor. The common terminal of the resistor R28 and the capacitor C25 is also grounded sequentially through the resistor R29 and the capacitor C26. The common terminal of the resistor R29 and the capacitor C26 is electrically connected to an external EMS.

[0006] The above oxygen sensor feedback circuit further has the following characteristics: it further includes a feedback optimization circuit. The input terminal of the feedback optimization circuit is electrically connected to the output control terminal of the external EMS, and the output terminal of the feedback optimization circuit is electrically connected to the common terminal of the resistor R28 and the capacitor C25.

[0007] The above-mentioned oxygen sensor feedback circuit further has the following characteristics. The feedback optimization circuit includes a second power supply VDDA2, a resistor R138, a triode Q6, a resistor R140, and a resistor R144. The second power supply VDDA2 is electrically connected to the emitter of the triode Q6. The emitter of the triode Q6 is electrically connected to its base through the resistor R138. The base of the triode Q6 is electrically connected to the output control terminal of the external EMS through the resistor R140. The collector of the triode Q6 is electrically connected to the common terminal of the resistor R28 and the capacitor C25 through the resistor R144.

[0008] The above-mentioned oxygen sensor feedback circuit further has the following characteristics. The first power supply VDDA1 provides a +5V voltage. The first power supply VDDA1 is applied to R107, R109, R28, and the oxygen sensor, so that the Icp current passing through the oxygen sensor is within a certain range.

[0009] The above-mentioned oxygen sensor feedback circuit further has the following characteristics. The second power supply VDDA2 also provides a +5V voltage. The function of the second power supply VDDA2 is to apply a pulsed current.

[0010] In summary, the beneficial effects of this solution are:

[0011] In the oxygen sensor feedback circuit provided by the present invention, by applying a pulsed current to the oxygen sensor, when the pulsed current passes through the oxygen sensor, the output voltage of the oxygen sensor will have an increment. According to this increment, the internal resistance of the oxygen sensor can be calculated. The oxygen sensor feedback circuit provided by the present invention has the effect of simultaneously satisfying the wake-up function and the detection function. Description of the Drawings

[0012] Figure 1 It is the circuit structure diagram of the first embodiment of the present invention;

[0013] Figure 2 It is the circuit structure diagram of the second embodiment of the present invention. Detailed Embodiments

[0014] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts belong to the scope of protection of the present invention.

[0015] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0016] The present utility model will be further described below in conjunction with specific embodiments, but it is not a limitation of the present utility model.

[0017] Figure 1 It is the circuit structure diagram of the first embodiment of the present utility model. Figure 2 It is the circuit structure diagram of the second embodiment of the present utility model. As Figure 1 and Figure 2 shown, the oxygen sensor feedback circuit provided in this embodiment includes a first power supply VDDA1, a resistor R107, a resistor R28, a resistor R109, a resistor R29, a capacitor C25, and a capacitor C26. The first power supply VDDA1 is grounded sequentially through the resistor R107 and the resistor R109. The common terminal of the resistor R107 and the resistor R109 is grounded sequentially through the resistor R28 and the capacitor C25. The common terminal of the resistor R28 and the capacitor C25 is electrically connected to an external oxygen sensor. The common terminal of the resistor R28 and the capacitor C25 is also grounded sequentially through the resistor R29 and the capacitor C26. The common terminal of the resistor R29 and the capacitor C26 is electrically connected to an external EMS.

[0018] In the above embodiment, a feedback optimization circuit is further included. The input terminal of the feedback optimization circuit is electrically connected to the output control terminal of the external EMS, and the output terminal of the feedback optimization circuit is electrically connected to the common terminal of the resistor R28 and the capacitor C25.

[0019] In the above embodiment, the feedback optimization circuit includes a second power supply VDDA2, a resistor R138, a triode Q6, a resistor R140, and a resistor R144. The second power supply VDDA2 is electrically connected to the emitter of the triode Q6. The emitter of the triode Q6 is electrically connected to its base through the resistor R138. The base of the triode Q6 is electrically connected to the output control terminal of the external EMS through the resistor R140. The collector of the triode Q6 is electrically connected to the common terminal of the resistor R28 and the capacitor C25 through the resistor R144.

[0020] In the above embodiment, the first power supply VDDA1 provides a +5V voltage. The first power supply VDDA1 is applied to R107, R109, R28, and the oxygen sensor, so that the Icp current passing through the oxygen sensor is within a certain range.

[0021] It should be noted that the range of Icp is 15 - 40uA. As long as it is within this range, the output accuracy of the oxygen sensor can be guaranteed.

[0022] In the above embodiment, the second power supply VDDA2 also provides a +5V voltage. The function of the second power supply VDDA2 is to apply a pulsed current.

[0023] Working principle: The first power supply VDDA1 is mainly used to generate the Icp current to produce the reference oxygen inside the zirconium element. This voltage is applied to resistor R107, resistor R109, resistor R28, and the oxygen sensor, so that the Icp current passing through the oxygen sensor can reach 15 - 40 μA. The second power supply VDDA2 is used to apply the pulsed current. When entering the PID control, the on-off interval of this voltage is controlled to apply the pulsed current. When entering the PID control, the Ri resistance value of the oxygen sensor is relatively low. At this time, the magnitude of the pulsed current is mainly affected by the resistance value of R144. When the pulsed current passes through the oxygen sensor, there will be an increment in the output voltage of the oxygen sensor, ΔV = Ri * I (where I is the pulsed current). According to Ri = ΔV / I, the internal resistance Ri value of the zirconium element at this time can be calculated.

[0024] The above are only the preferred embodiments of the present invention, and do not limit the implementation manners and protection scope of the present invention accordingly. For those skilled in the art, it should be realized that all the equivalent replacements and obvious changes made by using the content of the specification of the present invention should be included in the protection scope of the present invention.

Claims

1. An oxygen sensor feedback circuit, characterized in that: The device comprises a first power supply VDDA1, a resistor R107, a resistor R28, a resistor R109, a resistor R29, a capacitor C25 and a capacitor C26. The first power supply VDDA1 is sequentially connected to ground through the resistor R107 and the resistor R109. The common end of the resistor R107 and the resistor R109 is sequentially connected to ground through the resistor R28 and the capacitor C25. The common end of the resistor R28 and the capacitor C25 is electrically connected to an external oxygen sensor. The common end of the resistor R28 and the capacitor C25 is also sequentially connected to ground through the resistor R29 and the capacitor C26. The common end of the resistor R29 and the capacitor C26 is electrically connected to an external EMS.

2. The oxygen sensor feedback circuit according to claim 1, characterized in that: It also includes a feedback optimization circuit, the input end of the feedback optimization circuit is electrically connected to the output control end of the external EMS, and the output end of the feedback optimization circuit is electrically connected to the common end of the resistor R28 and the capacitor C25.

3. An oxygen sensor feedback circuit according to claim 2, characterized in that: The feedback optimization circuit includes a second power supply VDDA2, a resistor R138, a transistor Q6, a resistor R140 and a resistor R144, the second power supply VDDA2 is electrically connected to the emitter of the transistor Q6, the emitter of the transistor Q6 is electrically connected to its base through the resistor R138, the base of the transistor Q6 is electrically connected to the output control end of the external EMS through the resistor R140, and the collector of the transistor Q6 is electrically connected to the common end of the resistor R28 and the capacitor C25 through the resistor R144.

4. The oxygen sensor feedback circuit according to claim 3, characterized in that: The first power supply VDDA1 provides a +5V voltage, and the first power supply VDDA1 is applied to R107, R109, R28 and the oxygen sensor, so that the Icp current passing through the oxygen sensor is within a certain range.

5. The oxygen sensor feedback circuit according to claim 3, characterized in that: The second power supply VDDA2 also provides a +5V voltage. The function of the second power supply VDDA2 is to apply a pulse current.

Images