Engine oxygen sensor calibration method, calibration device and vehicle

Abstract

This invention discloses a method, device, and vehicle for calibrating an engine's oxygen sensor. The method includes: verifying whether starting conditions are met, including starting within a preset time after engine shutdown; or, the engine coolant temperature being within a preset temperature. If so, the starter motor is controlled to drive the engine, and the engine's air exchange process is statistically analyzed to determine if the preset conditions are met. If so, the oxygen sensor heating is activated, and the oxygen sensor obtains a measured standard oxygen concentration value. The correspondence between the measured oxygen concentration value and the output oxygen concentration value is corrected based on the measured standard oxygen concentration value. This invention enables automatic calibration without disassembling the oxygen sensor, avoiding damage due to thermal stress and eliminating the labor and maintenance costs required for sensor calibration.

Description

Technical Field

[0001] This invention relates to engine sensor technology, and more particularly to an oxygen sensor calibration method, calibration device, and vehicle for an engine. Background Technology

[0002] During the use of a vehicle, maintenance is an important and indispensable key.

[0003] In related technologies, oxygen sensor maintenance for engines is often performed by removing the oxygen sensor from the engine exhaust pipe. This is not only time-consuming but also costly. Especially for gas engines, because gas fuels have a higher hydrogen content than gasoline, the large amount of water vapor produced during combustion can condense on the ceramic surface of the oxygen sensor. Due to the presence of condensation on the ceramic surface, abruptly activating the oxygen sensor may cause uneven thermal stress on the ceramic surface during high-temperature heating, leading to cracks and damage. Therefore, oxygen sensors for gas engines require removal, wiping, and then maintenance and calibration. Summary of the Invention

[0004] This invention provides a method, device, and vehicle for calibrating an engine oxygen sensor, which enables automatic calibration without removing the engine oxygen sensor, eliminating the labor time and maintenance costs required for sensor calibration.

[0005] In a first aspect, embodiments of the present invention provide a method for calibrating an engine's oxygen sensor, comprising:

[0006] Verify whether the starting conditions are met, wherein the starting conditions include the starting time being within a preset time after the engine stops; or, the starting conditions include the engine coolant temperature being within a preset temperature.

[0007] If so, control the starter motor to drive the engine and count whether the engine's air exchange process meets the preset conditions;

[0008] If so, the oxygen sensor is activated, and the oxygen sensor obtains the measured standard oxygen concentration value;

[0009] The correspondence between the measured oxygen concentration value and the output oxygen concentration value is corrected based on the measured standard oxygen concentration value.

[0010] Optionally, controlling the starter motor to drive the engine includes:

[0011] The starter motor is intermittently controlled to drive the engine;

[0012] The running time is the first time length, and the pause time is the second time length.

[0013] Optionally, controlling the starter motor to drive the engine includes:

[0014] When the starter motor is below the cooling temperature, control the starter motor to drive the engine.

[0015] When the starter motor is above the protection temperature, control the starter motor to stop;

[0016] The cooling temperature is lower than the protection temperature.

[0017] Optionally, the preset condition includes the cumulative running time of the starter motor reaching a preset running time.

[0018] Optionally, the preset condition includes that when the starter motor drives the engine, the engine air exchange volume reaches a preset air exchange volume.

[0019] Optionally, activating the oxygen sensor includes controlling the oxygen sensor to self-heat to a preset self-heating temperature.

[0020] Optionally, correcting the correspondence between the measured oxygen concentration value and the output oxygen concentration value based on the measured standard oxygen concentration value includes:

[0021] If the deviation between the measured standard oxygen concentration value and the atmospheric oxygen concentration value is within a preset deviation, a correction value is determined based on the measured standard oxygen concentration value. The correction value is used to combine the measured oxygen concentration value to obtain the output oxygen concentration value.

[0022] Optionally, correcting the correspondence between the measured oxygen concentration value and the output oxygen concentration value based on the measured standard oxygen concentration value includes:

[0023] If the deviation between the measured standard oxygen concentration value and the atmospheric oxygen concentration value is greater than the preset deviation, the calibration of the oxygen sensor will be terminated and an oxygen sensor fault information will be reported.

[0024] Secondly, embodiments of the present invention also provide an oxygen sensor calibration device for an engine, comprising:

[0025] A startup condition verification module is used to verify whether startup conditions are met. The startup conditions include a startup time within a preset time after the engine stops; or, the startup conditions include an engine coolant temperature within a preset temperature.

[0026] The ventilation control module is used to control the starter motor to drive the engine and to count whether the engine's ventilation process meets preset conditions.

[0027] An oxygen concentration acquisition module is used to activate an oxygen sensor, which obtains a measured standard oxygen concentration value.

[0028] The correspondence determination module is used to correct the correspondence between the measured oxygen concentration value and the output oxygen concentration value based on the measured standard oxygen concentration value.

[0029] Thirdly, embodiments of the present invention also provide a vehicle using the oxygen sensor calibration method of any of the above-mentioned engines.

[0030] The oxygen sensor calibration method for an engine in this embodiment of the invention includes verifying whether the starting conditions are met. The starting conditions include the starting time being within a preset time after the engine stops. Alternatively, the starting conditions include the engine coolant temperature being within a preset temperature. If so, the starter motor is controlled to drive the engine, and the engine's air exchange process is statistically analyzed to see if the preset conditions are met. If so, the oxygen sensor is activated, and the oxygen sensor obtains a measured standard oxygen concentration value. The correspondence between the measured oxygen concentration value and the output oxygen concentration value is corrected based on the measured standard oxygen concentration value. Shortly after the engine stops, the engine and exhaust pipe still have residual heat. Therefore, by using the starter motor to drive the engine, the engine's operation allows the gas in the engine and exhaust pipe to flow and be heated, causing the condensate on the oxygen sensor to be blown off and dried by the flowing hot air. On the other hand, because the starter motor drives the engine, the air in the engine exhaust pipe frequently exchanges with the outside air, making the gas composition in the engine exhaust pipe similar to that of the air. This achieves the goal of exposing the oxygen sensor to air without disassembling it, providing a basis for the calibration steps. The embodiments of the present invention enable automatic calibration without disassembling the oxygen sensor, thus avoiding damage to the oxygen sensor due to thermal stress and eliminating the time and maintenance costs required for calibrating the sensor. Attached Figure Description

[0031] Figure 1 A flowchart illustrating the steps of an oxygen sensor calibration method for an engine provided in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the structure of an oxygen sensor calibration device for an engine provided in an embodiment of the present invention. Detailed Implementation

[0033] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0034] Figure 1 A flowchart illustrating the steps of an engine oxygen sensor calibration method provided in this embodiment of the invention is shown below. Figure 1 This invention provides a method for calibrating an engine's oxygen sensor, comprising:

[0035] S1: Verify whether the starting conditions are met. Starting conditions include the starting time being within a preset time after the engine stops; or, starting conditions include the engine coolant temperature being within a preset temperature.

[0036] The oxygen sensor can be a wide-range oxygen sensor. The preset time and temperature can be determined according to actual needs. The purpose of setting the starting conditions is that after the engine stops, the engine and exhaust pipe temperatures are relatively high. The heat from the engine and exhaust pipe can then be used for the following operations. The control of the engine, starter motor, and oxygen sensor can be accomplished using the vehicle's electronic control unit (ECU).

[0037] If so, proceed with operation S21.

[0038] S21: Control the starter motor to drive the engine and count whether the engine's air exchange process meets the preset conditions.

[0039] In this process, the oxygen sensor is required to measure the oxygen concentration in subsequent steps. Heating the oxygen sensor is necessary for accurate oxygen concentration measurement. For typical wide-range oxygen sensors, the measured lambda and NOx concentrations are only reliable when operating at around 800 degrees Celsius. Therefore, the wide-range oxygen sensor needs to self-heat to 800 degrees Celsius. However, before heating, considering that water vapor in the exhaust pipe will condense and form water droplets on the ceramic surface of the wide-range oxygen sensor after the engine stops, directly heating the sensor with water vapor or condensed water droplets would cause thermal stress and cracks in the ceramic, resulting in damage. Therefore, dew point detection is performed before heating the wide-range oxygen sensor. This invention provides a dew point detection method: after starting the engine, the starter motor drives the engine, using the engine's exhaust energy to continuously blow away and dry the water droplets on the wide-range oxygen sensor. The preset conditions for passing the dew point detection can be determined according to actual needs. For example, this invention provides the following two optional preset conditions. Optionally, the preset condition includes the cumulative running time of the starter motor reaching a preset running time. Alternatively, preset conditions may include ensuring that the engine's air exchange volume reaches a preset air exchange volume when the starter motor is running and driving the engine. After a preset time or preset air exchange volume has been purged and dried, the water droplets on the wide-range oxygen sensor are considered to be gone, and the dew point detection is deemed successful. The preset running time and preset air exchange volume can both be determined according to actual needs.

[0040] Because the starter motor generates a large amount of heat when driving the engine, this invention provides two starter motor control methods to prevent overheating and protect the motor. Optionally, controlling the starter motor to drive the engine includes intermittently controlling the starter motor to drive the engine. The running time is a first time length, and the pause time is a second time length. The first and second time lengths can be determined according to actual needs. After the starter motor runs for the first time length, it pauses for the second time length. This alternation of starting and pausing allows the starter motor to cool sufficiently, preventing damage from overheating. Alternatively, controlling the starter motor to drive the engine includes: controlling the starter motor to drive the engine when it is below the cooling temperature; and controlling the starter motor to stop when it is above the protection temperature. The cooling temperature is lower than the protection temperature. The cooling temperature and protection temperature can be determined according to actual needs. By measuring the real-time temperature of the starter motor, the operating state of the starter motor can be determined based on the relationship between the real-time temperature, the cooling temperature, and the protection temperature, ensuring that the motor is not damaged by overheating.

[0041] If the starting conditions are not met, proceed with operation S22, which ends the engine oxygen sensor calibration.

[0042] If the engine's scavenging process meets the preset conditions, then operation S31 is performed.

[0043] S31: Activate oxygen sensor heating, and the oxygen sensor obtains the measured standard oxygen concentration value.

[0044] Specifically, when controlling the oxygen sensor heating, the sensor can be controlled to self-heat to a preset self-heating temperature, which can be determined according to actual needs. After reaching the preset self-heating temperature, the oxygen sensor is used to measure the lambda value (i.e., oxygen concentration) in the exhaust pipe.

[0045] If the engine's scavenging process does not meet the preset conditions, then operation S32 is performed, i.e., the scavenging operation continues.

[0046] S4: Correct the correspondence between the measured oxygen concentration value and the output oxygen concentration value based on the measured standard oxygen concentration value.

[0047] Since the oxygen concentration in the air is stable and fixed, this characteristic can be used to determine the measurement error value of the oxygen sensor. Optionally, if the deviation between the measured standard oxygen concentration value and the atmospheric oxygen concentration value is within a preset deviation, a correction value is determined based on the measured standard oxygen concentration value. This correction value is used to combine with the measured oxygen concentration value to obtain the output oxygen concentration value. The preset deviation can be determined according to actual needs. For example, the electronic control unit in the vehicle can calculate the error between the measured oxygen concentration value and the actual oxygen concentration of the gas being measured based on the measured standard oxygen concentration value measured by the wide-range oxygen sensor, and correct the correspondence between the measured oxygen concentration value and the output oxygen concentration value based on the error. The obtained correspondence between the measured oxygen concentration value and the output oxygen concentration value can be stored in memory. This correspondence can be read when measuring oxygen concentration values ​​later, so as to provide the corrected output oxygen concentration value to the ECU based on the measured oxygen concentration value. Optionally, if the deviation between the measured standard oxygen concentration value and the atmospheric oxygen concentration value is greater than the preset deviation, the oxygen sensor calibration is ended and oxygen sensor fault information is reported. The oxygen sensor's error should be within a preset deviation. If it exceeds the preset deviation, it indicates a malfunction in the oxygen sensor. In this case, the oxygen sensor malfunction information should be reported to the ECU, reminding the user to replace it promptly.

[0048] This invention utilizes a starter motor to drive an engine. The engine's operation causes airflow and heating within the engine and exhaust pipe, allowing condensation on the oxygen sensor to be blown off and dried by the hot air. Furthermore, the engine's operation facilitates frequent air exchange between the exhaust pipe and ambient air, resulting in a gas composition in the exhaust pipe that closely resembles that of ambient air. This achieves the goal of exposing the oxygen sensor to air without disassembling it, providing a basis for calibration. This invention enables automatic calibration without disassembling the oxygen sensor, avoiding damage due to thermal stress and eliminating the time and maintenance costs associated with sensor calibration.

[0049] Figure 2 A schematic diagram of an oxygen sensor calibration device for an engine provided in an embodiment of the present invention is shown below. Figure 2 This invention also provides an oxygen sensor calibration device for an engine, comprising:

[0050] The starting condition verification module 1 is used to verify whether the starting conditions are met. The starting conditions include the starting time being within a preset time after the engine stops; or, the starting conditions include the engine water tank temperature being within a preset temperature.

[0051] The ventilation control module 2 is used to control the starter motor to drive the engine and to count whether the engine's ventilation process has met the preset conditions.

[0052] Oxygen concentration acquisition module 3 is used to activate the oxygen sensor, and the oxygen sensor obtains the measured standard oxygen concentration value;

[0053] The correspondence determination module 4 is used to correct the correspondence between the measured oxygen concentration value and the output oxygen concentration value based on the measured standard oxygen concentration value.

[0054] Shortly after the engine stops, the engine and exhaust pipe still retain residual heat. Therefore, by starting the engine with a starter motor, the engine's operation causes the gases in the engine and exhaust pipe to flow and be heated, allowing the condensate on the oxygen sensor to be blown off and dried by the flowing hot air. On the other hand, because the starter motor drives the engine, the air in the engine exhaust pipe frequently exchanges with the outside air, making the gas composition in the engine exhaust pipe similar to that of air. This achieves the goal of exposing the oxygen sensor to air without disassembling it, providing a basis for the calibration process. This embodiment of the invention achieves automatic calibration without disassembling the oxygen sensor, avoiding damage to the oxygen sensor due to thermal stress and eliminating the time and maintenance costs required for sensor calibration.

[0055] Optionally, controlling the starter motor to drive the engine may include:

[0056] Intermittently control the starter motor to drive the engine;

[0057] The running time is the first time length, and the pause time is the second time length.

[0058] Optionally, controlling the starter motor to drive the engine includes:

[0059] When the starter motor is below its cooling temperature, control the starter motor to drive the engine.

[0060] When the starter motor is above the protection temperature, control the starter motor to stop;

[0061] The cooling temperature is lower than the protection temperature.

[0062] Optionally, preset conditions include the cumulative running time of the start-up motor reaching a preset running time.

[0063] Optionally, preset conditions include that when the starter motor drives the engine, the engine's air exchange volume reaches a preset air exchange volume.

[0064] Optionally, activating oxygen sensor heating includes controlling the oxygen sensor to self-heat to a preset self-heating temperature.

[0065] Optionally, correcting the correspondence between the measured oxygen concentration value and the output oxygen concentration value based on the measured standard oxygen concentration value includes:

[0066] If the deviation between the measured standard oxygen concentration value and the atmospheric oxygen concentration value is within the preset deviation, then a correction value is determined based on the measured standard oxygen concentration value. The correction value is used to combine with the measured oxygen concentration value to obtain the output oxygen concentration value.

[0067] Optionally, correcting the correspondence between the measured oxygen concentration value and the output oxygen concentration value based on the measured standard oxygen concentration value includes:

[0068] If the deviation between the measured standard oxygen concentration and the atmospheric oxygen concentration is greater than the preset deviation, the oxygen sensor calibration will be terminated and an oxygen sensor fault information will be reported.

[0069] This invention also provides a vehicle using an oxygen sensor calibration method for any of the aforementioned engines.

[0070] Since the embodiments of the present invention use any of the above-mentioned oxygen sensor calibration methods for engines, they have the beneficial effects corresponding to the oxygen sensor calibration methods for engines.

[0071] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although 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 concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method for calibrating an oxygen sensor for an engine, characterized in that, include: Verify whether the starting conditions are met, including that the starting time is within a preset time after the engine stops; Alternatively, the starting conditions include the engine coolant temperature being within a preset temperature range; If so, the starter motor is controlled to drive the engine to run, and the air exchange process of the engine is counted to see if it meets the preset conditions; wherein, the preset conditions include, the cumulative running time of the starter motor reaches the preset running time; or, when the starter motor drives the engine to run, the air exchange volume of the engine reaches the preset air exchange volume. If so, the oxygen sensor is activated to heat up, and the oxygen sensor obtains the measured standard oxygen concentration value; The correspondence between the measured oxygen concentration value and the output oxygen concentration value is corrected based on the measured standard oxygen concentration value. The step of correcting the correspondence between the measured oxygen concentration value and the output oxygen concentration value based on the measured standard oxygen concentration value includes: If the deviation between the measured standard oxygen concentration value and the atmospheric oxygen concentration value is within a preset deviation, a correction value is determined based on the measured standard oxygen concentration value. The correction value is used to combine the measured oxygen concentration value to obtain the output oxygen concentration value. If the deviation between the measured standard oxygen concentration value and the atmospheric oxygen concentration value is greater than the preset deviation, the calibration of the oxygen sensor will be terminated and an oxygen sensor fault information will be reported.

2. The oxygen sensor calibration method for an engine according to claim 1, characterized in that, The control of the starter motor to drive the engine includes: The starter motor is intermittently controlled to drive the engine; The running time is the first time length, and the pause time is the second time length.

3. The oxygen sensor calibration method for an engine according to claim 1, characterized in that, The control of the starter motor to drive the engine includes: When the starter motor is below the cooling temperature, control the starter motor to drive the engine. When the starter motor is above the protection temperature, control the starter motor to stop; The cooling temperature is lower than the protection temperature.

4. The oxygen sensor calibration method for an engine according to claim 1, characterized in that, The activation of oxygen sensor heating includes controlling the oxygen sensor to self-heat to a preset self-heating temperature.

5. An oxygen sensor calibration device for an engine, characterized in that, include: The start-up condition verification module is used to verify whether the start-up conditions are met, including that the start-up time is within a preset time after the engine stops. Alternatively, the starting conditions include the engine coolant temperature being within a preset temperature range; The ventilation control module is used to control the starter motor to drive the engine and to count whether the engine's ventilation process has reached preset conditions; wherein, the preset conditions include, the cumulative running time of the starter motor reaches a preset running time; or, when the starter motor drives the engine, the engine ventilation volume reaches a preset ventilation volume. An oxygen concentration acquisition module is used to activate an oxygen sensor, which obtains a measured standard oxygen concentration value. The correspondence determination module is used to correct the correspondence between the measured oxygen concentration value and the output oxygen concentration value based on the measured standard oxygen concentration value. The step of correcting the correspondence between the measured oxygen concentration value and the output oxygen concentration value based on the measured standard oxygen concentration value includes: If the deviation between the measured standard oxygen concentration value and the atmospheric oxygen concentration value is within a preset deviation, a correction value is determined based on the measured standard oxygen concentration value. The correction value is used to combine the measured oxygen concentration value to obtain the output oxygen concentration value. If the deviation between the measured standard oxygen concentration value and the atmospheric oxygen concentration value is greater than the preset deviation, the calibration of the oxygen sensor will be terminated and an oxygen sensor fault information will be reported.

6. A vehicle, characterized in that, The oxygen sensor calibration method for the engine according to any one of claims 1-4.

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