DE102017206399A1 - DEVICE AND METHOD FOR CONTROLLING AN OXYGEN SENSOR - Google Patents

Abstract

An oxygen sensor control apparatus and an oxygen sensor control method are disclosed. The oxygen sensor control apparatus includes: an internal combustion engine that burns a fuel and generates a power; an oxygen sensor that measures an air-fuel ratio of an exhaust gas that has been generated when the fuel has been burned, and that includes a heater; and a controller that: checks whether an engine starting environment satisfies a setting mode detecting state of an air-fuel ratio control point after starting the engine; the heater operates when the engine starting environment satisfies the adjustment mode detection state so that a heater temperature reaches a predetermined temperature range; monitors the heater temperature while maintaining an operating state of the heater; checks if the heater temperature is changed and sets the air-fuel ratio control point based on the checked result.

Description

Technical area

The present disclosure relates to an apparatus for controlling an oxygen sensor that monitors a temperature of an oxygen sensor to raise an air-fuel ratio control point. In addition, the present disclosure relates to a method of controlling the oxygen sensor.

background

As environmental problems increase, regulations regarding exhaust emissions have recently become increasingly severe in order to reduce the exhaust gas emitted from internal combustion engine vehicles. Due to the tightening of the exhaust emission regulations, it is important to control the exhaust gas during an engine cold start. In this case, a heater to an oxygen sensor (also called lambda sensor or lambda sensor) is attached, which is activated only above a certain temperature. Heating activates the oxygen sensor for quick deployment.

However, in exhaust system devices that are in a cold state, condensate is formed below a condensation temperature upon contact with a vapor during engine cold start. In a case where the condensate comes in contact with a ceramic tip of the high-temperature heated oxygen sensor, the oxygen sensor is damaged by a thermal shock.

Accordingly, the oxygen sensor needs to be heated at a time when an amount of the condensate in an exhaust port after the start of the engine is significantly reduced.

Conventionally, the condensation point is measured for each vehicle type, with process modeling performed for each vehicle type, however, a detection timing of activation of an oxygen sensor is delayed because the condensation point is influenced by the environment of the vehicle.

In another example, the oxygen sensor is activated based on a coolant temperature after a certain amount of fuel has been consumed, or an air-fuel ratio control is limited in a condensation temperature range while a certain amount of fuel has been continuously consumed in an open loop. As a result, an area is formed where control with respect to the exhaust emission regulations and meaningful fuel economy are not possible.

Summary

The present disclosure has been made to solve the above-mentioned problems encountered in the prior art while retaining advantages achieved by the prior art.

One aspect of the present disclosure provides an apparatus for controlling an oxygen sensor that monitors a temperature of an oxygen sensor to raise an air-fuel ratio control point, and a method for controlling the oxygen sensor.

The technical problems to be solved by the present inventive concept are not limited by the above-mentioned problems, and those skilled in the art to which the present disclosure pertains will undeniably refer to the following description for technical problems not mentioned herein.

According to one aspect of the present disclosure, an apparatus for controlling an oxygen sensor includes: an internal combustion engine that burns a fuel and generates a power; an oxygen sensor that measures an air-fuel ratio of an exhaust gas generated when the fuel is burned and a heater; and a controller that: checks whether an engine starting environment satisfies a setting mode detection state of an air-fuel ratio control point after the engine start; the heater operates when the engine starting environment satisfies the adjustment mode detection state so that a heater temperature reaches a predetermined temperature range; monitors the heater temperature while maintaining an operating state of the heater; checks if the heater temperature is changed and sets the air-fuel ratio control point based on the checked result.

The engine starting environment includes the heater temperature and an engine stop time.

The adjustment mode detection state includes a state that requires the heater temperature to be equal to or lower than an ambient air temperature.

The setting mode detecting state includes a state requiring that the Engine stop time must be equal to or greater than a critical time.

If the heater temperature is not changed, then the controller checks whether a total heater hold time exceeds an air-fuel ratio control delay time while maintaining the heater operating state.

If the total heater hold time exceeds the air-fuel ratio control delay time, then the controller updates and adjusts the air-fuel ratio control delay time to the total heater hold time.

In addition, when the heater temperature is changed, the controller maintains the operating state of the heater for a predetermined time to monitor the heater temperature.

If the engine starting environment does not satisfy the setting mode detecting state, then the controller checks whether a predetermined air-fuel ratio control delay time elapses after the engine startup.

When the predetermined air-fuel ratio control delay time elapses, the controller activates the oxygen sensor.

According to one aspect of the present disclosure, a method of controlling an oxygen sensor includes: checking whether an engine starting environment satisfies a setting mode detection state of an air-fuel ratio control point after the engine start; Operating a heater of the oxygen sensor when the engine start environment satisfies the adjustment mode detection state to allow a heater temperature to reach a predetermined temperature range; Monitoring the heater temperature while maintaining an operating condition of the heater when the heater temperature reaches the predetermined temperature range; and adjusting the air-fuel ratio control point based on whether the heater temperature has changed.

The method further comprises, before the step of checking, whether the combustion engine starting environment satisfies the adjustment mode detection state: measuring an ambient air temperature and a relative humidity when a vehicle is started; Starting an internal combustion engine after the ambient air temperature and the relative humidity have been measured; and operating the heater of the oxygen sensor when a heater on delay time elapses after the start of the internal combustion engine.

The heater on delay time is determined based on ambient air temperature and relative humidity.

The step of checking whether the engine starting environment satisfies the adjustment mode detection state includes a step of checking whether the heater temperature is equal to or lower than the ambient air temperature.

The step of checking whether the engine starting environment satisfies the adjustment mode detection state includes a step of checking whether an engine stop time is equal to or greater than a critical time.

The step of setting the air-fuel ratio control point includes a step of checking whether a total heater holding time exceeds an air-fuel ratio control delay time while maintaining the operating state of the heater when the heater temperature is not changed, and one Step of updating and adjusting the air-fuel ratio control delay time to the total heater hold time when the total heater hold time exceeds the air-fuel ratio control delay time.

If the engine starting environment does not satisfy the adjustment mode detection state, then the oxygen sensor is activated after the elapse of the air-fuel ratio control delay time.

list of figures

• 1 ein Blockdiagramm ist, welches eine Sauerstoffsensor-Steuervorrichtung gemäß einer beispielhaften Ausführungsform der vorliegenden Offenbarung zeigt;
• 2 ein Flussdiagramm ist, welches ein Sauerstoffsensor-Steuerverfahren gemäß einer beispielhaften Ausführungsform der vorliegenden Offenbarung zeigt; und
• 3 eine Kurve ist, welche einen Luft-Kraftstoff-Verhältnis-Steuerpunkt gemäß einer beispielhaften Ausführungsform der vorliegenden Offenbarung zeigt.

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:

• 1 FIG. 10 is a block diagram showing an oxygen sensor control apparatus according to an exemplary embodiment of the present disclosure; FIG.
• 2 FIG. 10 is a flowchart showing an oxygen sensor control method according to an exemplary embodiment of the present disclosure; FIG. and
• 3 FIG. 10 is a graph showing an air-fuel ratio control point according to an exemplary embodiment of the present disclosure. FIG.

Detailed description

It is intended that the foregoing description be understood to embody, except as otherwise stated, the terms "comprising," "forming," and / or "comprising" the presence of listed components, but not the presence or addition of one or more exclude several other components.

In addition, the terms such as "part", "area", "module", etc. described in the specification mean a unit of complete configuration that performs at least one function or operation, and hardware or software or a combination of hardware and software is implemented. In addition, the terms "a," "an," and "the" used herein in the singular are intended to encompass the plural forms as well, unless the context clearly dictates otherwise.

Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

1 FIG. 10 is a block diagram showing an oxygen sensor control apparatus according to an exemplary embodiment of the present disclosure.

Regarding 1 For example, the oxygen sensor control device includes a fuel tank 110 , an injector 120 , an internal combustion engine 130 , an exhaust pipe 140 , an oxygen sensor 150 and a controller 160.

The fuel tank 110 is a steel container that stores a fuel for a vehicle, with a pump in the fuel tank 110 is installed to generate a fuel pressure, and wherein a gas outlet at an upper portion of the fuel tank 110 is arranged. A pressure reducing valve is installed at the gas outlet. The fuel tank 110 can store compressed natural gas (CNG) and may have a domed shape.

The injector 120 is a fuel injector incorporating a solenoid valve which supplies the fuel in response to a command from the controller 150 sprayed spray signal sprayed or sprayed. The injector 120 sprayed in the fuel tank 110 stored fuel in each cylinder (that is, combustion chamber) of the internal combustion engine 130 ,

The internal combustion engine 130 burns the fuel in the cylinder and drives a piston in an up and down motion to produce a mechanical power output. The internal combustion engine 130 provides a force to drive the wheels of the vehicle.

The exhaust pipe 140 expels the exhaust gas, which in the combustion of the fuel in the internal combustion engine 130 has been generated.

The oxygen sensor 150 is on the exhaust pipe 140 installed to measure an amount of oxygen in the through the exhaust pipe 140 discharged exhaust gas is contained. In other words, the oxygen sensor 150 measures an air-fuel ratio (air weight / fuel weight). The oxygen sensor 150 may be implemented as a zirconia oxygen sensor, as a titania oxygen sensor, or as a broadband oxygen sensor. For example, the oxygen sensor 150 be implemented as a universal exhaust gas oxygen (UEGO) sensor.

The oxygen sensor 150 includes a heater 151. The heater 151 heats the oxygen sensor 150 to a predetermined temperature (eg, about 600 ° C to about 800 ° C) such that a pumping cell that controls movement of oxygen ions of the oxygen sensor 150 allows, and a measuring cell, which measures a concentration of residual oxygen in the exhaust gas, are operated evenly. In this case, the controller controls 160 one by the heater 151 flowing current using a pulse width modulation (PWM) method.

The control 160 is an engine control unit (ECU) which controls the injector 120 controls to a lot of the cylinder of the internal combustion engine 130 Adjust or adjust the supplied fuel. The control 160 controls an operating time of the injector 120 on the basis of the amount of oxygen contained in the exhaust gas, which with the oxygen sensor 150 is measured to adjust the amount of fuel. In other words, the controller 160 subtracts the amount of fuel measured by the oxygen sensor 150 from a target fuel amount to calculate an error in the amount of the fuel, and corrects the target fuel amount based on the calculated error, thereby increasing the amount of the engine 130 supplied fuel is adjusted or adjusted.

The control 160 deactivates the oxygen sensor 150 at the beginning of the engine start before the Condensation temperature is reached, in which case a constant amount of fuel is consumed continuously. The condensation temperature point corresponds to a time at which the heating device 151 is operated after elapse of a predetermined period of time so as to prevent the oxygen sensor 150 is damaged by a thermal shock due to the condensate at the start of engine start.

The control 160 includes a processor 161 and a storage device 162 ,

The processor 161 controls an overall operation of the controller 160 , The storage unit 162 stores programs and input / output data for the operation of the controller 160 ,

The storage device 162 may store a heater-on delay time, a heater hold time, an air-fuel ratio control delay time (an oxygen sensor control delay time), a critical-temperature change amount, set data, and the like. The storage device 162 can store data measured with the vehicle-mounted sensors (for example, a temperature sensor, a humidity sensor, etc.).

The storage device 162 may be implemented at least by the memory of a flash memory, a hard disk, an SD card, a random access memory (RAM), a read-only memory (ROM) or a web memory.

If the vehicle is supplied with a source voltage, then the processor measures 161 using a temperature sensor (not shown) and a humidity sensor (not shown), an ambient air temperature and a relative humidity, which are installed in the vehicle. The processor 161 calculates the heater on delay time based on the measured ambient air temperature and the measured relative humidity.

Then the processor starts 161 the internal combustion engine 150 to operate the vehicle. That is, the processor 161 controls the injector 120 and leads to the cylinder of the internal combustion engine 150 the fuel to the internal combustion engine 150 to operate.

The processor 161 checks if the heater-on delay time after starting the engine 150 has passed. If the heater on delay time has elapsed after the start of the engine 150, then the processor is operating 161 the heater 151 of the oxygen sensor 150 to the oxygen sensor 150 heat. In other words, the processor 161 operates the heater 151 when a predetermined time has elapsed after the start of the engine 150.

The processor 161 checks whether an engine starting environment satisfies a condition for detecting a setting mode (a detection state for setting the air-fuel ratio control point) to set the air-fuel ratio control point. Here, the adjustment mode detection state means that a heater temperature (a temperature of the oxygen sensor) is equal to or lower than the ambient air temperature, and that an engine stop time (a time elapsed after the engine stop) is equal to or greater than a critical time ,

If the engine start environment meets the set mode detection state, then the processor checks 161 whether the heater temperature is in a predetermined temperature range (eg, more than about 90 ° C and less than about 100 ° C). In this case, the processor measures 161 a resistance of the heater 151 and calculates the heater temperature (the temperature of the oxygen sensor) using the measured resistance value.

If the heater temperature is in the predetermined temperature range, then the processor stops 161 the operating state of the heater 151 during the predetermined heater hold time and monitors the heater temperature. The processor 161 controls the heater 151 supplied current so that it is constant during the heater hold time. The processor 161 calculates a change amount at 0 ° C of the heater temperature (T).

The processor 161 monitors the heater temperature and checks if the heater temperature has changed. In other words, the processor 161 checks whether the change amount of the heater temperature exceeds a change amount of a critical temperature.

If there is no change in heater temperature, then the processor checks 161 whether an overall heater hold time exceeds the air-fuel ratio control delay time stored in the storage means 162. If the total heater hold time exceeds the air-fuel ratio control delay time, then the processor updates and resets 161 the air- Fuel ratio control delay time on the total heater hold time.

If the heater temperature is changed then the processor will fit 161 the heater hold time, additionally holds the operation state of the heater 151 during the adjusted heater hold time, and monitors the heater temperature. If there is no change in heater temperature, then the processor determines 161 whether to set the air-fuel ratio control delay time to the total heater hold time. If the total heater hold time is greater than the air-fuel ratio control delay time, then the processor updates 161 the air-fuel ratio control delay time to the total heater hold time. For example, if the heater temperature has changed while the heater temperature has been monitored for 5 seconds in which the operating state of the heater 151 is maintained, then the heater temperature is monitored for an additional 3 seconds in which the heater's operating condition 151 is maintained. As a result, if the heater temperature is not changed and the total heater hold time (eg, 8 seconds (= 5 seconds + 3 seconds)) is greater than the air / fuel ratio control delay time (eg, 6 seconds), then the processor resets 161 the air-fuel ratio control delay time to 8 seconds.

If the engine start environment does not satisfy the set mode detection state, then the processor checks 161 whether the predetermined air-fuel ratio control delay time has elapsed after the engine start. If the predetermined air-fuel ratio control delay time has elapsed, then the processor activates 161 the oxygen sensor 150 , In other words, the processor 161 controls the oxygen sensor 150 after waiting the predetermined air-fuel ratio control delay time. In this case, the processor controls 161 that of the heater 151 supplied power to the oxygen sensor 150 to heat. For example, the processor increases 161 an amount of the current supplied to the heater 151 to the oxygen sensor 150 to heat to the heater temperature of about 680 ° C.

2 FIG. 10 is a flowchart showing an oxygen sensor control method according to an exemplary embodiment of the present disclosure.

When the source voltage is applied to the vehicle (S110), then the controller measures 160 ambient air temperature and relative humidity (S120). When the vehicle is switched on (key position "On"), the controller measures 160 the ambient air temperature and relative humidity using the temperature sensor and the humidity sensor installed in the vehicle. Then put the controller 160 the heater on delay time based on the measured ambient air temperature and the measured relative humidity.

The control 160 starts the combustion engine 130 and operates the vehicle after measuring ambient air temperature and relative humidity (S130).

The control 160 checks whether the heater ON delay time has elapsed after the engine start (S140). The control 160 checks whether an elapsed time after the start of the engine exceeds the heater on delay time. In this case, the controller measures 160 the elapsed time after the start of the internal combustion engine using a timer (not shown).

After elapse of the heater on delay time, the controller operates 160 the heater 151 to the oxygen sensor 150 to heat up (S150). The solution 160 supplies the heater 151 with electricity to generate the heat, causing the oxygen sensor 150 is heated.

The control 160 checks whether the engine starting environment satisfies the setting mode detecting state of the air-fuel ratio control point (S160). The control 160 checks whether the heater temperature (the temperature of the oxygen sensor) is equal to or lower than the ambient air temperature, and whether the engine stop time is equal to or greater than the critical time (for example, 8 hours).

When the engine start environment satisfies the adjustment mode detection state of the air-fuel ratio control point, the controller 160 checks whether the heater temperature is in the predetermined temperature range (S170). For example, the controller checks 160 whether the heater temperature exceeds about 90 ° C and less than about 100 ° C.

If the heater temperature is in the predetermined temperature range, then the controller stops 160 the operating state the heater 151 during the predetermined heater holding time and monitors the heater temperature (S180). In this case, the controller calculates 160 the heater temperature using the resistance value of the heater 151 ,

The control 160 checks if there is a change in the heater temperature (S190). The control 160 checks whether the change amount of the heater temperature exceeds the change amount of the critical temperature.

If there is no change in heater temperature, then the controller checks 160 whether the total heater hold time exceeds the air-fuel ratio control delay time (S200). In other words, if the change amount of the heater temperature is equal to or smaller than the change amount of the critical temperature, then the control checks 160 whether the total heater holding time in which the operating state of the heater is maintained exceeds the predetermined air-fuel ratio control delay time.

If the total heater hold time exceeds the predetermined air-fuel ratio control delay time, then the controller 160 sets and updates the air-fuel ratio control delay time to the total heater hold time (S210). The control 160 updates the air-fuel ratio control delay time stored in the storage means 162 to the total heater holding time.

If the heater temperature is changed, then the controller fits 160 the predetermined heater holding time (S220). If the amount of change of the heater temperature exceeds the amount of change of the critical temperature, then the controller will fit 160 the predetermined heater holding time. The control 160 additionally holds the operating status of the heater 151 during the adjusted heater hold time and monitors the heater temperature to check for a change in heater temperature (S180 and S190).

If the engine starting environment does not satisfy the setting mode detecting state in operation (S160), the controller checks 160 whether the predetermined air-fuel ratio control delay time has elapsed (S230). If the heater temperature exceeds the ambient air temperature or if the engine stop time is less than the critical time (eg, 8 hours), then the controller waits 160 during the predetermined air-fuel ratio control delay time.

If the predetermined air-fuel ratio control delay time has elapsed, then the controller activates 160 the oxygen sensor 150 (S240). If the predetermined air-fuel ratio control delay time has elapsed after the start of the engine, then the controller 160 controls the oxygen sensor 150 , In this case, the controller checks 160 Whether the heater temperature reaches the predetermined temperature (for example, about 680 ° C), and when the heater temperature reaches the predetermined temperature according to the checked result, then the controller controls 160 the oxygen sensor 150 to adjust the air-fuel ratio.

3 FIG. 10 is a graph showing an air-fuel ratio control point according to an exemplary embodiment of the present disclosure. FIG.

As in 3 is shown, when the predetermined time has elapsed after the start of the internal combustion engine, the controller operates 160 the heater 151 of the oxygen sensor 150 until the heater temperature reaches about 100 ° C. Then the controller stops 160 the operating state of the heater 151 , controls the oxygen sensor 150 to a low temperature of about 100 ° C, and monitors the change in heater temperature. The control 160 monitors the heater temperature during a heater on-hold period T _M. In this case, the change T _V in the heater temperature occurs in a region (A) in which the condensate exists, and the change T _{V of} the heater temperature does not occur in a period T _C where the condensate does not exist.

If there is no change in heater temperature, the controller will raise 160 the air-fuel ratio control point T _CS resources to the control of the oxygen sensor 150 to start. The controller 160 controls the heater 151 until the heater temperature reaches the temperature of about 680 ° C. When the heater temperature has reached the temperature of about 680 ° C, then the controller activates 160 the oxygen sensor 150 to control the air-fuel ratio.

Although it has been described above that all the components which configure the exemplary embodiment of the present invention as described above are coupled in a unit or operated by being coupled with each other, the present invention is not necessarily limited to them limited exemplary embodiments. That is, all components may be operated by being selectively coupled together within the scope of the present invention. All components may be implemented in independent hardware, however, some or all of the corresponding components may optionally be combined to be implemented as a computer program which combines a program module to perform some or all of the functions in one or a plurality of hardware modules. Components has. Program encodings and portions of program encodings that make up the computer program can be easily derived by a computer programmer in this field. In addition, the computer program may be stored in computer readable recording media and may be read and executed by a computer, thereby implementing the method of the present disclosure.

According to the present invention, the temperature of the oxygen sensor is monitored, whereby the air-fuel ratio control point can be raised. Accordingly, a control detection point of emission regulations with respect to the exhaust gas may be raised, and the control of the exhaust gas may be performed earlier, thereby improving fuel efficiency.

In addition, according to the present invention, the oxygen sensor may be controlled according to a vehicle driving environment and a vehicle characteristic.

Furthermore, the effort for the determination and the time for setting the condensation point in an early development time of the vehicle can be reduced.

Claims (16)

Apparatus for controlling an oxygen sensor, comprising: an internal combustion engine configured to combust fuel and generate a power; an oxygen sensor configured to measure an air-fuel ratio of an exhaust gas generated upon combustion of the fuel and a heater; and a controller designed to: check whether an engine starting environment satisfies a setting mode detection state of an air-fuel ratio control point after the engine start, operate the heater when the engine starting environment satisfies the adjustment mode detection state so that a heater temperature reaches a predetermined temperature range; monitor the heater temperature while maintaining an operating condition of the heater, to check if the heater temperature has changed, and set the air-fuel ratio control point based on the checked result. Device after Claim 1 wherein the engine starting environment includes the heater temperature and an engine stop time. Device after Claim 2 wherein the adjustment mode detection state includes a state that requires the heater temperature to be equal to or lower than an ambient air temperature. Device after Claim 2 wherein the adjustment mode detection state includes a state that requires the engine stop time to be equal to or greater than a critical time. Device after Claim 1 wherein, if the heater temperature is not changed, the controller checks whether a total heater hold time exceeds an air-fuel ratio control delay time while maintaining the heater operating state. Device after Claim 5 wherein, when the total heater hold time exceeds the air-fuel ratio control delay time, the controller updates and sets the air-fuel ratio control delay time to the total heater hold time. Device after Claim 1 wherein, when the heater temperature is changed, the controller additionally maintains the operating state of the heater for a predetermined period of time to monitor the heater temperature. Device after Claim 1 wherein, when the engine starting environment does not satisfy the setting mode detecting condition, the controller checks whether a predetermined air-fuel ratio control delay time elapses after the engine start. Device after Claim 8 wherein, when the predetermined air-fuel ratio control delay time elapses, the controller activates the oxygen sensor. A method of controlling an oxygen sensor, comprising: Checking whether an engine starting environment satisfies a setting mode detecting state of an air-fuel ratio control point after an engine start; Operating a heater of the oxygen sensor when the engine start environment satisfies the adjustment mode detection state to allow a heater temperature to reach a predetermined temperature range; Monitoring the heater temperature while maintaining an operating condition of the heater when the heater temperature reaches the predetermined temperature range; and Adjusting the air-fuel ratio control point based on whether the heater temperature is changed. Method according to Claim 10 further comprising, prior to verifying that the engine starting environment meets the adjustment mode detection condition: measuring ambient air temperature and relative humidity when powering a vehicle; Starting an internal combustion engine after the ambient air temperature and the relative humidity have been measured; and operating the heater of the oxygen sensor when a heater-on delay time elapses after the start of the engine. Method according to Claim 11 wherein the heater on delay time is determined based on ambient air temperature and relative humidity. Method according to Claim 10 wherein the step of checking whether the engine starting environment satisfies the adjustment mode detection state comprises a step of checking whether the heater temperature is equal to or less than an ambient air temperature. Method according to Claim 10 wherein the step of checking whether the combustion engine starting environment satisfies the adjustment mode detection state comprises a step of checking whether an engine stop time is equal to or greater than a critical time. Method according to Claim 10 wherein the step of adjusting the air-fuel ratio control point comprises: checking whether a total heater hold time exceeds an air-fuel ratio control delay time while maintaining the heater operating state when the heater temperature is not changed; and updating and setting the air-fuel ratio control delay time to the total heater hold time when the total heater hold time exceeds the air-fuel ratio control delay time. Method according to Claim 15 wherein if the engine starting environment does not satisfy the adjustment mode detection state, the oxygen sensor is activated after the air-fuel ratio control delay time has elapsed.

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