Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/14—Introducing closed-loop corrections
  • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
  • F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
  • F02D41/1446—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being exhaust temperatures
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
  • G01M15/00—Testing of engines
  • G01M15/04—Testing internal-combustion engines
  • G01M15/10—Testing internal-combustion engines by monitoring exhaust gases or combustion flame
  • G01M15/102—Testing internal-combustion engines by monitoring exhaust gases or combustion flame by monitoring exhaust gases
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/04—Introducing corrections for particular operating conditions
  • F02D41/042—Introducing corrections for particular operating conditions for stopping the engine
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/14—Introducing closed-loop corrections
  • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/14—Introducing closed-loop corrections
  • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
  • F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
  • F02D41/1466—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being a soot concentration or content
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/14—Introducing closed-loop corrections
  • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
  • F02D41/1493—Details
  • F02D41/1494—Control of sensor heater
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N37/00—Details not covered by any other group of this subclass
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/14—Introducing closed-loop corrections
  • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
  • F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
  • F02D2041/1472—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being a humidity or water content of the exhaust gases

Definitions

• a method for operating an exhaust gas sensor in an exhaust tract of an internal combustion engine of a vehicle is already known from the prior art, the exhaust gas sensor having a ceramic sensor element with at least one measuring electrode and a heating device, based on data that the internal combustion engine and the exhaust gas sensor concern, a binary dew point end signal is calculated which indicates whether the occurrence of liquid water in the exhaust tract is still to be expected or no longer.
• the invention is based on the understanding of the inventors that this damage is frost damage to the ceramic sensor element, which can occur in individual cases. If a vehicle is parked in a state in which the ceramic sensor element is wet, i.e. water adheres to the sensor element on the surface or in pores, and the sensor element subsequently cools below the freezing point of the water, the latter freezes and the water with it associated increase in volume is the cause of potential damage to the sensor element.
• the invention proposes that whenever the vehicle is parked and at the same time the dew point signal has the value that signals that the occurrence of liquid water in the exhaust tract is still to be expected, the sensor element through its Heating device is heated to a temperature for a certain time so that the sensor element dries at least on its surface or even completely.
• the proposal here includes both the possibility of starting heating of the sensor element after the time at which the vehicle is parked, i.e. the sensor element was not previously heated, and the possibility that the sensor element was already heated before Parking the vehicle was heated (for example, also with the aim of drying the sensor element, for example at 150 ° C - 300 ° C or at 175 ° C to 250 ° C) and continues to be heated after parking the vehicle (for example furthermore at 150 ° C - 300 ° C or at 175 ° C to 250 ° C).
• the sensor element dries and even if the exhaust gas sensor is exposed to low temperatures at a later point in time, frost damage cannot occur since there is little or no liquid water on the sensor element or in pores of the sensor element.
• the measure is taken that the sensor element is heated by its heating device for a certain time to a temperature such that the sensor element dries at least on its surface or even completely.
• a further condition can be one of the following conditions: a) A battery voltage of a battery electrically connected to the exhaust gas sensor is within a permissible range, for example above 12 V or above 12.4 V b) The ambient temperature is below 5 ° C. c) The total operating time of the exhaust gas sensor is not more than 100 hours or not more than 300 hours. d) A shunt current determined in a previous measurement phase is no more than 1 mA.
• a further development of the method provides that the measure described is also taken if, when the vehicle is parked, the end of the dew point signal has the value that signals that liquid water is no longer to be expected in the exhaust tract, but at the same time the measurement request signal has the value which signals that the exhaust gas sensor should not be performing any exhaust gas measurement at the moment. In this case, too, drying a sensor element that is possibly still damp reliably prevents subsequent frost damage.
• a further development of the method provides that the measure described is not taken if, when the vehicle is parked, the end of the dew point signal has the value that signals that liquid water is no longer to be expected in the exhaust tract, and at the same time the measurement request signal has the value which signals that the exhaust gas sensor is currently to carry out an exhaust gas measurement.
• the sensor element is dry, and it would also be counterproductive to intervene in the measurement to be carried out at the moment by heating.
• the certain time can be at least 40 seconds or at least 50 seconds or even at least 100 seconds and / or the temperature can be at least 150 ° C, for example 150 ° C to 300 ° C. It can be provided, for example, that the temperature is kept at a constant value, in particular regulated, during the certain time.
• the conceptual prerequisite for parking the vehicle is that the vehicle comes to a standstill and the internal combustion engine is stopped.
• further measures are required in particular, which make it clear that the journey and / or the operation of the internal combustion engine are not should be resumed promptly.
• this can be expressed through the manual or automated opening of an ignition switch, for example by means of an ignition key or similar measures.
• at least one control unit of the vehicle can start a follow-up phase that precedes the complete or extensive shutdown of this control unit and prepares it.
• the mere stopping of the internal combustion engine as part of an automatic start-stop or a purely electric drive phase in a hybrid vehicle then does not constitute stopping the vehicle in the sense of the invention.
• the exhaust gas sensor can be, for example, a particle sensor, the measuring function of which is to collect particles on the surface of the sensor element and to evaluate their electrical conductivity.
• the measuring function of the particle sensor can also provide that the collection of particles is preceded by a regeneration of the sensor element in which the sensor element is heated to such an extent that particles adhering to it, in particular soot particles, burn.
• the heating element of the sensor element can, for example, be an electrical resistance structure that can be contacted from outside.
• the invention also relates to a computer program which is set up to carry out the steps of the method according to one of the preceding claims, and to an electronic control unit which comprises a non-volatile memory on which such a computer program is stored.
• FIG. 1 and 2 show a particle sensor that is connected to an electronic control unit
• FIG. 3 shows an example of the implementation of the method according to the invention
• FIGS. 4 and 5 further examples for carrying out the method according to the invention.
• FIG. 1 shows a plan view of a particle sensor 10 for detecting particles in a measurement gas according to an embodiment of the present invention.
• the particle sensor 10 is designed, in particular, to detect soot particles in a gas flow, such as an exhaust gas flow, an internal combustion engine, and for installation in an exhaust gas line of a motor vehicle.
• the particle sensor 10 is designed as a soot sensor and can be arranged downstream of a soot particle filter of a motor vehicle with a diesel internal combustion engine.
• the measurement gas is exhaust gas from an internal combustion engine of a vehicle.
• the particle sensor 10 comprises a sensor element 12.
• the sensor element 12 comprises a substrate 14.
• the substrate 14 is made of a ceramic material, for example.
• the substrate 14 is essentially cuboid.
• the sensor element 12 further comprises a first electrode 16, a second electrode 18, a first lead 20 and a second lead 22.
• the first electrode 16, the second electrode 18, the first lead 20 and the second lead 22 are on an upper side 24 of the Substrate 14 arranged.
• the first electrode 16 and the second electrode 18 are designed as interdigital electrodes.
• the first electrode 16 is connected to the first lead 20.
• the second electrode 18 is connected to the second supply line 22.
• the first feed line 20 and the second feed line 22 represent connection contacts which are designed for electrically contacting the first electrode 16 and the second electrode 18.
• the first electrode 16 and the second electrode 18 are designed to carry out a current and / or voltage measurement.
• the particle sensor 10 has a heating element 30 on its underside 25, which is shown in FIG.
• the electronic control unit 26 is, for example, an engine control unit of an internal combustion engine.
• the electronic control device has an electronic storage medium 28 on which a computer program is stored.
• the computer program contains instructions for carrying out a method for operating the particle sensor 10. Such a method is described in more detail below with reference to FIG.
• the temperature T of the sensor element 12 is shown in a temporal sequence that extends from a time t0 preceding in time to a subsequent time t3; it can, for example, assume the values low (for example 20 ° C.) and high (for example 200 ° C.).
• the binary signals end of dew point (TPE) and measurement request (MA) are also shown.
• the end of the dew point signal can on the one hand assume the value “-”, which means that the occurrence of liquid water in the exhaust tract is still to be expected, and on the other hand assume the value “+”, which means that the occurrence of liquid water in the exhaust tract can no longer be expected.
• the measurement request signal can on the one hand assume the value “-”, which means that no exhaust gas measurement should be carried out at the moment, and on the other hand the value “+”, which means that an exhaust gas measurement should be carried out at the moment.
• the state of the vehicle's ignition is also shown.
• the ignition is in the “on” state, which means that an ignition switch is closed and the internal combustion engine is in operation or can be started immediately and the vehicle is not switched off.
• the ignition also has the “off” state, which means that an ignition switch is open, for example an ignition key of the vehicle has been removed from an ignition lock of the vehicle and the internal combustion engine is neither in operation nor can it be started immediately, i.e. the vehicle is turned off within the meaning of the invention.
• the ignition is switched on at the point in time t0, which precedes the time sequence under consideration. There is no measurement request, the end of the dew point signal indicates that condensation water must still be expected in the exhaust system.
• the sensor element 12 has a low temperature.
• the temperature T is 200 ° C; the certain time is for example 60 seconds.
• the temperature T is kept constant for a certain time by regulation.
• the sensor element 12 is then, for example, completely or partially dried and is subsequently no longer heated. So it cools down.
• the temperature T of the sensor element 12 is shown in a different time sequence, which extends from a temporally preceding point in time t0 to a temporally subsequent point in time t3, as in FIG. 3.
• the binary signal dew point end (TPE) is shown, as in FIG. 3.
• the ignition Z can assume the states “on” and “off”, as explained above.
• the engine designed as an internal combustion engine can assume the states “on” and “off”, depending on whether it is in internal combustion engine operation or not.
• the ignition is switched on at time t0, which precedes the time sequence under consideration. However, the engine stays off.
• the sensor element can optionally be heated for a very short point in time, for example in order to verify the basic functionality of its heating device.
• the ignition Z continues to be on, the motor M continues to be off, and the end of the dew point signal signals that condensation water must still be expected in the exhaust tract.
• the sensor element 12 has already cooled down to a low temperature T by this point in time.
• the temperature T is 200 ° C; the certain time is for example 60 seconds.
• the temperature T is kept constant for a certain time by regulation.
• the sensor element 12 is then, for example, completely or partially dried and is subsequently no longer heated. So it cools down.
• FIG. 4 Also shown in FIG. 4 (dash-dotted line) is a previously known strategy, according to which the sensor element can be heated for a very short time after the vehicle has been parked (time t3), for example to verify the basic functionality of its heating device .
• FIG. 5 Another time sequence is shown in FIG. 5. It differs from that shown in FIG. 4, first of all, in that at time t0, in addition to closing the ignition circuit, the internal combustion engine operation of the engine is also started. In response to this, the sensor element is heated to an elevated temperature, for example 200 ° C.
• a battery voltage of a battery electrically connected to the exhaust gas sensor is within a permissible range, for example above 12 V or above 12.4 V,
• the ambient temperature is below 5 ° C
• the total operating time of the exhaust gas sensor is no more than 100 hours (e.g. if the end of the dew point signal (TPE) has the value that signals that liquid water is still to be expected in the exhaust tract) or no more than 300 hours (e.g. regardless of the value of the dew point signal (TPE)),
• a shunt current determined in a previous measurement phase does not exceed 1 mA.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Life Sciences & Earth Sciences (AREA)
• Health & Medical Sciences (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Combined Controls Of Internal Combustion Engines (AREA)
• Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
• Measuring Oxygen Concentration In Cells (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=74495603

Family Applications (1)

Country Status (8)

Families Citing this family (2)

Family Cites Families (12)

• 2019
  • 2019-12-27 DE DE102019220584.4A patent/DE102019220584A1/de active Pending
• 2020
  • 2020-07-10 US US17/634,432 patent/US20220326119A1/en active Pending
  • 2020-07-10 KR KR1020227008619A patent/KR20220047617A/ko unknown
  • 2020-07-10 WO PCT/EP2020/069546 patent/WO2021032360A1/de unknown
  • 2020-07-10 MX MX2022002015A patent/MX2022002015A/es unknown
  • 2020-07-10 CA CA3151703A patent/CA3151703A1/en active Pending
  • 2020-07-10 EP EP20742193.4A patent/EP4018087A1/de active Pending
  • 2020-07-10 CN CN202080073268.1A patent/CN114585806A/zh active Pending

Also Published As

Similar Documents

Legal Events