EP0635148B1 - System for operating a heating element for a ceramic sensor in a motor vehicle - Google Patents

System for operating a heating element for a ceramic sensor in a motor vehicle Download PDF

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Publication number
EP0635148B1
EP0635148B1 EP94900746A EP94900746A EP0635148B1 EP 0635148 B1 EP0635148 B1 EP 0635148B1 EP 94900746 A EP94900746 A EP 94900746A EP 94900746 A EP94900746 A EP 94900746A EP 0635148 B1 EP0635148 B1 EP 0635148B1
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EP
European Patent Office
Prior art keywords
temperature
internal combustion
combustion engine
ceramic sensor
operating state
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EP94900746A
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German (de)
French (fr)
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EP0635148A1 (en
Inventor
Eberhard Schnaibel
Erich Schneider
Konrad Henkelmann
Frank Blischke
Georg Mallebrein
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Robert Bosch GmbH
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Robert Bosch GmbH
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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05G—CONTROL DEVICES OR SYSTEMS INSOFAR AS CHARACTERISED BY MECHANICAL FEATURES ONLY
    • G05G23/00—Means for ensuring the correct positioning of parts of control mechanisms, e.g. for taking-up play
    • 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

Definitions

  • the invention relates to a system for operating a heating element for a ceramic sensor in a motor vehicle according to the preamble of claim 1.
  • Such a system for operating a heating element for a ceramic Sensor in a motor vehicle is from US Pat. No. 4,348,583 known.
  • the current is pulsed, so that in the second time interval with reduced Power is heated.
  • This type of control of the The heating element becomes high during the first time interval provided to a desired temperature if possible to reach quickly.
  • In the second time interval is reduced Power heated to maintain the temperature.
  • the invention has for its object in a system of the beginning mentioned type for operating a heating element for a ceramic Sensor in a motor vehicle depending on the operating state an internal combustion engine driving the motor vehicle different Set sensor temperatures.
  • Another object of the invention is the ceramic Protect the sensor from damage caused by impinging liquid. At the same time, the ceramic sensor should be ready for operation as quickly as possible and the sensor signals should be affected as little as possible become.
  • the invention is also intended to protect the ceramic Sensor without any structural changes to the sensor or with allow only minor structural changes and inexpensive be.
  • the invention has the advantage that it is one on the respective Operating state of the internal combustion engine adjusted setting of Temperature TSe of the ceramic sensor enables. It is a first Operating state (phase I) of the internal combustion engine defined in which it is to be expected that liquid in the exhaust duct of the internal combustion engine is present and a second operating state (phase II), in which is not to be expected that in the exhaust duct of the internal combustion engine Liquid is present. If the internal combustion engine is in the first operating state, the heating element is not in Started or the heating element is controlled so that the ceramic sensor operated below a critical temperature TSeK becomes. The critical temperature TSeK is chosen so that the Operation of the ceramic sensor below the critical temperature TSeK no significant risk of damage to the ceramic Sensor in contact with liquid. Is the Internal combustion engine in the second operating state, so the control the heating element, for example, to an optimal operating temperature of the ceramic sensor.
  • the distinction between the two operating states mentioned in the control the heating element has the advantage that the risk of damage of the ceramic sensor through contact with liquid is cleared and thus the life of the ceramic sensor can be extended without constructive changes to the sensor must be made.
  • the heating element is exemplary embodiment during the first operating state the internal combustion engine is not put into operation or Operated with reduced power or first with high and then operated with reduced power. The transition from the high to reduced performance occurs if since the start of the Internal combustion engine has passed a selectable period of time or if it can be assumed that the temperature TSe of the ceramic Sensor has exceeded a threshold TSel. Whether the threshold TSel is exceeded, can result from the temperature-dependent properties of the ceramic sensor or the signal of one in thermal Contact with the ceramic sensor standing temperature sensor be determined.
  • the last one has the advantage that the ceramic sensor is very quickly to the maximum permissible temperature under the given circumstances is heated. This ensures that the optimal operating temperature of the ceramic sensor within a short time the transition from the first to the second operating state of the internal combustion engine can be adjusted. All three measures to Protection of the ceramic sensor is common in that they are only taken if necessary, i.e. during the first Operating state.
  • the first operating state is after a cold start of the internal combustion engine in front.
  • a cold start is assumed if the coolant temperature the engine at the start below one Threshold value TKM1 lies.
  • the transition from the first to the second operating state the internal combustion engine takes place if from the beginning a selectable period of time has elapsed from the first operating state or if it can be assumed that the temperature TAbg of the exhaust system a threshold value TTau in the vicinity of the ceramic sensor has exceeded.
  • the latter can be derived from the signal from a temperature sensor, which is installed in the vicinity of the ceramic sensor or from a model that the temperature TAbg of the exhaust system in describes the environment of the ceramic sensor approximately become.
  • the system according to the invention can be particularly advantageous with a Use oxygen probe in the exhaust gas duct of the internal combustion engine seen in the flow direction of the exhaust gases before or after a catalyst is appropriate.
  • FIG. 1 is a schematic representation of an internal combustion engine the components essential to the invention
  • Figure 2 is a flow diagram of the system for operation according to the invention a heating element for an oxygen probe
  • FIG. 3 shows diagrams for the time profile of the heating element electrical power (top), the temperature TSe of the Oxygen probe (center) and the temperature TAbg of the exhaust system in the environment of the oxygen probe (below) and
  • Figure 4 is a block diagram of a device used to determine can be determined whether the temperature TSe of the oxygen probe Has exceeded the threshold TSel.
  • the invention is described below using the example of an oxygen probe, which is located in the exhaust duct of an internal combustion engine.
  • the oxygen probe is used to measure the oxygen content of the Exhaust gas to record and a device for controlling the To provide air / fuel ratio. So far the oxygen probe is usually very far forward in the exhaust duct, i.e. close to the internal combustion engine, attached to rapid heating the oxygen probe through the exhaust gases of the internal combustion engine to ensure. To heat the oxygen probe even faster it is usually provided with an electric heating element. Furthermore, it can be ensured by the heating element that the oxygen probe even under operating conditions under which the Exhaust gas temperature is low and / or only a very small amount Exhaust gas is present, is kept at operating temperature.
  • FIG. 1 shows a schematic representation of an internal combustion engine 100 with the components essential to the invention.
  • an intake tract 102 and an exhaust duct 104 are attached on the internal combustion engine 100 .
  • a sensor 108 for detection the temperature of the intake air and an injector 110.
  • Im Exhaust gas duct 104 of internal combustion engine 100 is located in the flow direction of the exhaust gases - an oxygen probe 112 with a heating element 114, a sensor 116 for detecting the temperature TAbg of the exhaust gases or the wall of the exhaust duct 104 in the vicinity of the oxygen probe 112, a catalyst 118 and optionally another Oxygen probe 120 with heating element 122 and another sensor 124 for recording the temperature TAbg of the exhaust gases or the wall of the Exhaust gas duct 104 in the vicinity of the oxygen probe 120.
  • a sensor 126 for detecting the coolant temperature of the engine 100 attached.
  • a control unit 128 is via supply lines with the air mass or air flow meter 106 the sensor 108, the injection nozzle 110, the oxygen probe 112, the heating element 114, the sensor 116, the oxygen probe 120, the Heating element 122, the sensor 124 and the sensor 126 connected.
  • the oxygen probe 120 is used to regulate the air / fuel ratio not absolutely necessary, so today's systems are out Often only equipped with oxygen probe 112 due to cost reasons are. For the future, a two-probe concept appears to be both contains the oxygen probe 112 as well as the oxygen probe 120, but gain in importance. For the description below the principle of operation of the invention becomes an embodiment with only one oxygen probe 112.
  • the Transfer to an embodiment with two oxygen probes 112 and 120 is very simple since each heating element 114, 122 is by itself on the same principle as in the embodiment with only one Oxygen probe 112 is controlled. A separate control is necessary because it can generally be assumed that that the oxygen probes 112 and 120 have different conditions are exposed. The differences can be particularly great after one Cold start of the internal combustion engine 100.
  • the catalyst has 118 a low temperature - usually around ambient temperature - and can initially large amounts of condensation store so that the exhaust gases on their way from the oxygen probe 112 cooled to oxygen probe 120 and enriched with liquid become.
  • the risk of damage from contact with liquid is therefore essential for the oxygen probe 120 longer period than with oxygen probe 112, so that the Protective measures for the oxygen probe 120 are accordingly longer are to be maintained.
  • the first operating state is usually after a cold start the internal combustion engine 100 as long as the temperature TAbg of the exhaust gas duct in the vicinity of the oxygen probe 112 is lower than the dew point temperature TTau of approx. 50 - 60 ° C.
  • the period within which is the internal combustion engine in the first operating state is referred to as Phase I below. Will the dew point temperature TTau exceeded, there is a transition to second operating state and a phase II begins.
  • the signal of Sensor 126 which is the temperature of the coolant of the internal combustion engine 100 recorded, evaluated. If the evaluation shows that the Temperature of the coolant is greater than a threshold TKM1, the For example, if it is 75 ° C, there is no cold start.
  • TKM1 a threshold
  • the Internal combustion engine 100 is in the second operating state and there are no further measures to protect the oxygen probe 112 required before damage due to contact with liquid, i.e. the control of the heating element 114 is subject to FIG no restrictions in this context. Is the temperature of the Coolant, on the other hand, is less than the threshold value TKM1 Cold start before and it can initially be assumed that the Internal combustion engine 100 is in the first operating state.
  • the heating element 114 remains switched off.
  • the heating element 114 is reduced with respect to its nominal power P1 Power P2 operated.
  • the heating element 114 is initially operated at its nominal power P1 and then if it can be assumed that the temperature TSe the Oxygen probe 112 has exceeded a threshold TSel the heating power P is reduced such that the temperature TSe Oxygen probe 112 no longer rises or only rises slightly.
  • the threshold TSel is approx. 50 K below a critical one Temperature TSeK of z. B. 300 to 350 ° C, above which the danger damage to oxygen probe 112 upon contact with liquid consists.
  • the temperature TSe of the oxygen probe 112 can be off the time that has passed since the heating element 114 was switched on is estimated or from the output signals of the oxygen probe 112 or from the signals of a temperature sensor, the is in thermal contact with oxygen probe 112 or determined by other methods familiar to the person skilled in the art.
  • phase I ends and phase II begins can either from empirical values collected during the application were determined approximately (option 1) or as follows be determined:
  • Figure 2 shows a flow diagram of a preferred embodiment of the system according to the invention for operating the heating element 114 of an oxygen probe 112.
  • measure 3 described above and the transition from phase I to phase II is according to one of those described above Possibilities 1, 2 or 3 determined.
  • the flow chart begins with a first step 200, in which the Internal combustion engine 100 is started. Then in one Step 202 queries whether the engine coolant temperature 100 is less than the threshold value TKMI. Is this condition a step 204 follows. In step 204 the heating element 114 is put into operation with the nominal power P1. Then in step 206 it is queried whether the temperature TSe Oxygen probe 112 has exceeded the threshold TSel. This The query is repeated until the queried condition is met is. If the condition is met, step 208 follows Step 208 asks whether it is to be assumed that liquid is present in the vicinity of the oxygen probe 112. To answer This question will address at least one of the three above Options 1, 2 or 3 used.
  • step 210 in which it is caused that the heating element 114 is reduced with respect to its nominal power P1 Power P2 is operated.
  • the reduction in power P can, for example, be clocked by the heating element 114 flowing electrical current.
  • Step 210 follows again Step 208.
  • step follows 212 in which the heating element 114 is caused to run at nominal power P1 is operated. You can also go to step 212 directly from step 202 come out when the condition of the step 202 is not satisfied, i.e. if there is no cold start and thus also no measures to protect the oxygen probe 112 from damage due to contact with liquid are required.
  • FIG. 3 shows diagrams for the time course of the heating element 114 supplied electrical power P (top), the temperature TSe of the oxygen probe 112 (middle) and the temperature TAbg in the Environment of the oxygen probe 112 (below).
  • Phase I which has already been defined further above, is in two Sub-phases divided. A sub-phase Ia and a subsequent one Sub-phase Ib. Phase II follows on from phase Ib. The single ones Phases or sub-phases are by vertical dashed lines separated from each other.
  • the temperature is on the ordinate TSe of the oxygen probe 112 plotted.
  • TSe the temperature of the oxygen probe 112 plotted.
  • an increase in temperature TSe from time t t0 as a result the heating by the heating element 114 to recognize.
  • the rise in temperature is additionally achieved by the oxygen sensor 112 passing exhaust affects.
  • the temperature is on the ordinate TAbg of the exhaust gas or the exhaust gas duct 104 is plotted.
  • phase Ia The end point of phase Ia is reached when the temperature TSe of the oxygen probe 112, the threshold TSel, for example 250 to 300 ° C.
  • the threshold TSel for example 250 to 300 ° C.
  • the sub-phase Ia ends and the sub-phase begins Ib.
  • the reduction the electrical power P has the consequence that the temperature TSe the oxygen probe 112 assumes an approximately constant value (see Figure 3, middle diagram).
  • the time of transition from sub-phase Ib to phase II results derive from the time course of the temperature TAbg.
  • TAbg remains on this Value until the liquid in the exhaust duct 104 in the vicinity of the Oxygen probe 112 and completely upstream in the gaseous Condition has passed.
  • the rise in temperature TAbg against End of sub-phase Ib thus indicates that in the area there is no more liquid in the oxygen probe 112. Out for this reason the time for the transition from sub-phase Ib falls after phase II with an increase in temperature TAbg above the dew point temperature Tau together.
  • the system according to the invention works more reliably the more precisely the times for the transition from phase Ia to Ib and for the Transition from sub-phase Ib to phase II can be determined. in the The following is explained using preferred exemplary embodiments, how to determine these times.
  • the properties of ceramic sensors are often temperature-dependent, so that the temperature TSe of the sensors in these cases without additional thermocouples determined from the behavior of the sensors can be. This also applies to the oxygen probe described here 112, whose electrical resistance increases with temperature decreases sharply.
  • Figure 4 shows a circuit known per se, from which electrical resistance of the oxygen probe 112 is determined whether the oxygen probe 112 has exceeded a threshold value TSel, i.e. the circuit serves the time of transition from Determine sub-phase Ia after sub-phase Ib.
  • the Oxygen probe 112 In addition to the change in resistance, when the temperature rises the Oxygen probe 112 has another effect. Usually delivers the oxygen probe 112 is already below the critical temperature TSeK a voltage that depends on the oxygen content of the exhaust gas, for example, when the threshold TSel is exceeded. So there is usually a temperature range in which the oxygen probe 112 is ready for operation without any noteworthy warning there is damage on contact with liquid.
  • the time of transition from phase Ib to phase II can be determine without the temperature sensor 116 using the following method, d. H. the temperature sensor 116 is for the invention System not absolutely necessary and can also be omitted. Then is using a model that shows the temperature profile of the exhaust gases simulates when the exhaust gases reach the dew point temperature TTau have exceeded.
  • the input variable is that of air mass or Airflow meter 106 senses air mass or airflow into the model fed.
  • the air mass or air volume is integrated in the model and the integral is determined empirically with one Threshold compared.
  • the threshold value represents that of the internal combustion engine 100 air masses sucked in since the cold start or the amount of air at which the temperature TAbg is known to be the Dew point temperature exceeds TTau. Once the under the model carried out comparison shows that the threshold reached , it can be assumed that the temperature TAbg is the dew point temperature TTau has exceeded.
  • Heating element 114 even before the engine 100 starts To take operation.
  • the commissioning triggered by a process that occurs before the start of the internal combustion engine 100 lies, for example opening the vehicle door, switching on the interior lighting, actuation of the belt buckle or Driver seat load. This allows the time between Start of the internal combustion engine 100 and the operational readiness of the Shorten oxygen probe 112, which z. B. in connection with a heated catalyst can be important. This variant too can the described measures to protect the oxygen probe 112 can be used.
  • the temperature TAbg represents the temperature in the vicinity of the Oxygen probe 112 or 120. Depending on the embodiment, it can the temperature of the exhaust gases, the wall of the exhaust duct 104 or the catalyst 118 act. If there is a possibility TAbg can also record several of these temperatures by Averaging over at least two of these temperatures can be determined.
  • the temperature of the wall can also be changed of the exhaust duct (104) or the temperature of the catalyst (118) can be used to determine whether a cold start of the internal combustion engine (100) is present.
  • the prerequisite for this is that a corresponding temperature sensor is available. If at Start of the internal combustion engine (100) that detected by this sensor Temperature is lower than the dew point temperature (TTau) Cold start before.
  • TTau dew point temperature

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)
  • Measuring Oxygen Concentration In Cells (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
  • Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)

Abstract

The invention relates to a system for operating a heating element (114) of a ceramic sensor (112) which is fitted in the exhaust gas channel (104) of an internal combustion engine (100) and can be heated by the heating element (114). If the operating mode of the internal combustion engine (100) is such that there could be liquid in its exhaust gas channel (104), the heating element (114) is not operated or is controlled in such a way that the ceramic sensor (112) is run below a critical temperature (TSeK). Above the critical temperature (TSe) there is the danger that the ceramic sensor (112) may be damaged by contact with the liquid.

Description

Stand der TechnikState of the art

Die Erfindung betrifft ein System zum Betreiben eines Heizelements für einen keramischen Sensor in einem Kraftfahrzeug gemäß dem Oberbegriff des Anspruchs 1.The invention relates to a system for operating a heating element for a ceramic sensor in a motor vehicle according to the preamble of claim 1.

Ein solches System zum Betreiben eines Heizelements für einen keramischen Sensor in einem Kraftfahrzeug ist aus der US-PS 4 348 583 bekannt. Dort wird ein Heizelement in einem ersten Zeitintervall mit einem konstanten Strom beaufschlagt. In einem zweiten Zeitintervall wird der Strom gepulst, so daß im zweiten Zeitintervall mit reduzierter Leistung geheizt wird. Mit dieser Art der Ansteuerung des Heizelements wird während des ersten Zeitintervalls eine hohe Heizleistung zur Verfügung gestellt, um eine gewünschte Temperatur möglichst schnell zu erreichen. Im zweiten Zeitintervall wird mit reduzierter Leistung geheizt, um die Temperatur zu halten.Such a system for operating a heating element for a ceramic Sensor in a motor vehicle is from US Pat. No. 4,348,583 known. There is a heating element in a first time interval a constant current is applied. In a second time interval the current is pulsed, so that in the second time interval with reduced Power is heated. With this type of control of the The heating element becomes high during the first time interval provided to a desired temperature if possible to reach quickly. In the second time interval is reduced Power heated to maintain the temperature.

Der Erfindung liegt die Aufgabe zugrunde, bei einem System der eingangs genannten Art zum Betreiben eines Heizelements für einen keramischen Sensor in einem Kraftfahrzeug abhängig vom Betriebszustand einer das Kraftfahrzeug antreibenden Brennkraftmaschine unterschiedliche Sensortemperaturen einzustellen. The invention has for its object in a system of the beginning mentioned type for operating a heating element for a ceramic Sensor in a motor vehicle depending on the operating state an internal combustion engine driving the motor vehicle different Set sensor temperatures.

Eine weitere Aufgabe der Erfindung besteht darin, den keramischen Sensor vor Beschädigung durch auftreffende Flüssigkeit zu schützen. Gleichzeitig soll der keramische Sensor möglichst schnell betriebsbereit sein und die Sensorsignale sollen möglichst wenig beeinträchtigt werden. Weiterhin soll die Erfindung einen Schutz des keramischen Sensors ganz ohne bauliche Veränderungen des Sensors bzw. mit nur geringen baulichen Veränderungen ermöglichen und kostengünstig sein.Another object of the invention is the ceramic Protect the sensor from damage caused by impinging liquid. At the same time, the ceramic sensor should be ready for operation as quickly as possible and the sensor signals should be affected as little as possible become. The invention is also intended to protect the ceramic Sensor without any structural changes to the sensor or with allow only minor structural changes and inexpensive be.

Diese Aufgabe wird durch den Anspruch 1 und die nachfolgend gekennzeichneten Merkmale gelöst.This object is characterized by claim 1 and those below Features resolved.

Vorteile der ErfindungAdvantages of the invention

Die Erfindung besitzt den Vorteil, daß sie eine auf den jeweiligen Betriebszustand der Brennkraftmaschine abgestimmte Einstellung der Temperatur TSe des keramischen Sensors ermöglicht. Es ist ein erster Betriebszustand (Phase I) der Brennkraftmaschine definiert, in dem damit zu rechnen ist, daß im Abgaskanal der Brennkraftmaschine Flüssigkeit vorhanden ist und ein zweiter Betriebszustand (Phase II), in dem nicht damit zu rechnen ist, daß im Abgaskanal der Brennkraftmaschine Flüssigkeit vorhanden ist. Wenn sich die Brennkraftmaschine im ersten Betriebszustand befindet, wird das Heizelement nicht in Betrieb genommen oder das Heizelement wird so angesteuert, daß der keramische Sensor unterhalb einer kritischen Temperatur TSeK betrieben wird. Die kritische Temperatur TSeK wird so gewählt, daß beim Betrieb des keramischen Sensors unterhalb der kritischen Temperatur TSeK keine nennenswerte Gefahr einer Beschädigung des keramischen Sensors bei Kontakt mit Flüssigkeit besteht. Befindet sich die Brennkraftmaschine im zweiten Betriebszustand, so kann die Ansteuerung des Heizelements beispielsweise auf eine optimale Betriebstemperatur des keramischen Sensors ausgerichtet sein. The invention has the advantage that it is one on the respective Operating state of the internal combustion engine adjusted setting of Temperature TSe of the ceramic sensor enables. It is a first Operating state (phase I) of the internal combustion engine defined in which it is to be expected that liquid in the exhaust duct of the internal combustion engine is present and a second operating state (phase II), in which is not to be expected that in the exhaust duct of the internal combustion engine Liquid is present. If the internal combustion engine is in the first operating state, the heating element is not in Started or the heating element is controlled so that the ceramic sensor operated below a critical temperature TSeK becomes. The critical temperature TSeK is chosen so that the Operation of the ceramic sensor below the critical temperature TSeK no significant risk of damage to the ceramic Sensor in contact with liquid. Is the Internal combustion engine in the second operating state, so the control the heating element, for example, to an optimal operating temperature of the ceramic sensor.

Die Unterscheidung der beiden genannten Betriebszustände bei der Ansteuerung des Heizelements hat den Vorteil, daß die Gefahr einer Beschädigung des keramischen Sensors durch Kontakt mit Flüssigkeit ausgeräumt wird und sich somit die Lebensdauer des keramischen Sensors verlängern läßt, ohne daß konstruktive Änderungen am Sensor vorgenommen werden müssen.The distinction between the two operating states mentioned in the control the heating element has the advantage that the risk of damage of the ceramic sensor through contact with liquid is cleared and thus the life of the ceramic sensor can be extended without constructive changes to the sensor must be made.

Ein weiterer Vorteil der Erfindung besteht darin, daß unterschiedlich aufwendige Maßnahmen zum Schutz des keramischen Sensors zur Verfügung stehen, mit denen sich in einem weiten Einsatzbereich ein guter Kompromiß zwischen Aufwand und Nutzen erzielen läßt. Je nach Ausführungsbeispiel wird das Heizelement während des ersten Betriebszustands der Brennkraftmaschine nicht in Betrieb genommen oder mit reduzierter Leistung betrieben oder zunächst mit hoher und anschließend mit reduzierter Leistung betrieben. Der Übergang von der hohen zur reduzierten Leistung erfolgt, wenn seit dem Start der Brennkraftmaschine eine wählbare Zeitspanne verstrichen ist oder wenn davon auszugehen ist, daß die Temperatur TSe des keramischen Sensors einen Schwellwert TSel überschritten hat. Ob der Schwellwert TSel überschritten ist, kann aus den temperaturabhängigen Eigenschaften des keramischen Sensors oder dem Signal eines in thermischen Kontakt mit dem keramischen Sensor stehenden Temperatursensors ermittelt werden.Another advantage of the invention is that different complex measures to protect the ceramic sensor Are available to deal with in a wide range of applications good compromise between effort and benefit can be achieved. Depending on The heating element is exemplary embodiment during the first operating state the internal combustion engine is not put into operation or Operated with reduced power or first with high and then operated with reduced power. The transition from the high to reduced performance occurs if since the start of the Internal combustion engine has passed a selectable period of time or if it can be assumed that the temperature TSe of the ceramic Sensor has exceeded a threshold TSel. Whether the threshold TSel is exceeded, can result from the temperature-dependent properties of the ceramic sensor or the signal of one in thermal Contact with the ceramic sensor standing temperature sensor be determined.

Von den drei genannten Maßnahmen zum Schutz des keramischen Sensors bietet die letzte den Vorteil, daß der keramische Sensor sehr schnell auf die unter den gegebenen Umständen höchstzulässige Temperatur geheizt wird. Dadurch wird erreicht, daß die optimale Betriebstemperatur des keramischen Sensors innerhalb kurzer Zeit nach dem Übergang vom ersten in den zweiten Betriebszustand der Brennkraftmaschine eingestellt werden kann. Allen drei Maßnahmen zum Schutz des keramischen Sensors ist gemeinsam, daß sie nur dann ergriffen werden, wenn es erforderlich ist, d.h. während des ersten Betriebszustands. Of the three measures mentioned to protect the ceramic sensor the last one has the advantage that the ceramic sensor is very quickly to the maximum permissible temperature under the given circumstances is heated. This ensures that the optimal operating temperature of the ceramic sensor within a short time the transition from the first to the second operating state of the internal combustion engine can be adjusted. All three measures to Protection of the ceramic sensor is common in that they are only taken if necessary, i.e. during the first Operating state.

Der erste Betriebszustand liegt nach einem Kaltstart der Brennkraftmaschine vor. Von einem Kaltstart geht man aus, falls die Kühlmitteltemperatur der Brennkraftmaschine beim Start unterhalb eines Schwellwerts TKM1 liegt. Der Übergang vom ersten zum zweiten Betriebszustand der Brennkraftmaschine erfolgt dann, wenn seit Beginn des ersten Betriebszustands eine wählbare Zeitspanne verstrichen ist oder wenn davon auszugehen ist, daß die Temperatur TAbg der Abgasanlage in der Umgebung des keramischen Sensors einen Schwellwert TTau überschritten hat. Letzteres kann aus dem Signal eines Temperatursensors, der in der Umgebung des keramischen Sensors angebracht ist oder aus einem Modell, das die Temperatur TAbg der Abgasanlage in der Umgebung des keramischen Sensors näherungsweise beschreibt, ermittelt werden.The first operating state is after a cold start of the internal combustion engine in front. A cold start is assumed if the coolant temperature the engine at the start below one Threshold value TKM1 lies. The transition from the first to the second operating state the internal combustion engine takes place if from the beginning a selectable period of time has elapsed from the first operating state or if it can be assumed that the temperature TAbg of the exhaust system a threshold value TTau in the vicinity of the ceramic sensor has exceeded. The latter can be derived from the signal from a temperature sensor, which is installed in the vicinity of the ceramic sensor or from a model that the temperature TAbg of the exhaust system in describes the environment of the ceramic sensor approximately become.

In dem Modell wird die seit dem Starten der Brennkraftmaschine angesaugte Luftmenge oder Luftmasse aufintegriert und das Integral wird mit einem Schwellwert verglichen. Die Vielzahl der hier dargestellten Kriterien, nach denen der Übergang vom ersten zum zweiten Betriebszustand ermittelt werden kann, erschließen der Erfindung ein weites Einsatzgebiet, indem sie viel Freiraum für die Berücksichtigung der jeweiligen technischen Gegebenheiten bieten.In the model, the one sucked in since the engine was started Air quantity or air mass integrated and the integral becomes compared to a threshold. The multitude of those shown here Criteria according to which the transition from the first to the second operating state can be determined, open up the invention wide area of application by leaving plenty of scope for consideration the respective technical conditions.

Besonders vorteilhaft läßt sich das erfindungsgemäße System bei einer Sauerstoff-Sonde einsetzen, die im Abgaskanal der Brennkraftmaschine in Stromrichtung der Abgase gesehen vor oder nach einem Katalysator angebracht ist.The system according to the invention can be particularly advantageous with a Use oxygen probe in the exhaust gas duct of the internal combustion engine seen in the flow direction of the exhaust gases before or after a catalyst is appropriate.

Zeichnungdrawing

Die Erfindung wird nachstehend anhand der in der Zeichnung dargestellten Ausführungsformen erläutert. The invention is described below with reference to the drawing Embodiments explained.

Es zeigenShow it

Figur 1 eine schematische Darstellung einer Brennkraftmaschine mit den erfindungswesentlichen Komponenten,Figure 1 is a schematic representation of an internal combustion engine the components essential to the invention,

Figur 2 ein Flußdiagramm des erfindungsgemäßen Systems zum Betrieb eines Heizelements für eine Sauerstoff-Sonde,Figure 2 is a flow diagram of the system for operation according to the invention a heating element for an oxygen probe,

Figur 3 Diagramme für den zeitlichen Verlauf der dem Heizelement zugeführten elektrischen Leistung (oben), der Temperatur TSe der Sauerstoff-Sonde (Mitte) und der Temperatur TAbg der Abgasanlage in der Umgebung der Sauerstoff-Sonde (unten) und3 shows diagrams for the time profile of the heating element electrical power (top), the temperature TSe of the Oxygen probe (center) and the temperature TAbg of the exhaust system in the environment of the oxygen probe (below) and

Figur 4 ein Blockschaltbild einer Einrichtung, mit der ermittelt werden kann, ob die Temperatur TSe der Sauerstoff-Sonde einen Schwellwert TSel überschritten hat.Figure 4 is a block diagram of a device used to determine can be determined whether the temperature TSe of the oxygen probe Has exceeded the threshold TSel.

Beschreibung der AusführungsbeispieleDescription of the embodiments

Die Erfindung wird im folgenden am Beispiel einer Sauerstoff-Sonde, die sich im Abgaskanal einer Brennkraftmaschine befindet, beschrieben. Prinzipiell ist ein Einsatz im Zusammenhang mit beliebigen beheizbaren keramischen Sensoren im Abgaskanal der Brennkraftmaschine denkbar. Die Sauerstoff-Sonde dient dazu, den Sauerstoffgehalt des Abgases zu erfassen und einer Einrichtung zur Regelung des Luft/Kraftstoff-Verhältnisses zur Verfügung zu stellen. Bislang wurde die Sauerstoff-Sonde in der Regel sehr weit vorne im Abgaskanal, d.h. nahe der Brennkraftmaschine, angebracht, um eine schnelle Erwärmung der Sauerstoff-Sonde durch die Abgase der Brennkraftmaschine zu gewährleisten. Um die Sauerstoff-Sonde noch schneller aufzuheizen ist sie in der Regel mit einem elektrischen Heizelement versehen. Des weiteren kann durch das Heizelement sichergestellt werden, daß die Sauerstoff-Sonde auch unter Betriebsbedingungen, unter denen die Abgastemperatur niedrig ist und/oder nur eine sehr geringe Menge an Abgas vorhanden ist, auf Betriebstemperatur gehalten wird.The invention is described below using the example of an oxygen probe, which is located in the exhaust duct of an internal combustion engine. In principle, use in connection with any heatable ceramic sensors in the exhaust duct of the internal combustion engine conceivable. The oxygen probe is used to measure the oxygen content of the Exhaust gas to record and a device for controlling the To provide air / fuel ratio. So far the oxygen probe is usually very far forward in the exhaust duct, i.e. close to the internal combustion engine, attached to rapid heating the oxygen probe through the exhaust gases of the internal combustion engine to ensure. To heat the oxygen probe even faster it is usually provided with an electric heating element. Furthermore, it can be ensured by the heating element that the oxygen probe even under operating conditions under which the Exhaust gas temperature is low and / or only a very small amount Exhaust gas is present, is kept at operating temperature.

Bei einer Montage der Sauerstoff-Sonde nahe der Brennkraftmaschine kann es aber zu Problemen kommen:

  • 1. Wenn die Brennkraftmaschine längere Zeit bei hoher Leistung betrieben wird, fällt eine große Menge sehr heißer Abgase an, durch die die Sauerstoff-Sonde möglicherweise auf unzulässig hohe Temperaturen aufgeheizt wird. Dadurch kann sich die Lebensdauer der Sauerstoff-Sonde verkürzen.
  • 2. Es ist in der Regel schwierig, im Abgaskanal nahe der Brennkraftmaschine eine geeignete Einbaustelle für die Sauerstoff-Sonde zu finden, von der aus die Abgase aller Zylinder der Brennkraftmaschine erfaßt werden können.
    • Problems can arise when installing the oxygen probe near the internal combustion engine:
  • 1. If the internal combustion engine is operated at high power for a long time, a large amount of very hot exhaust gases is produced, which may heat up the oxygen probe to impermissibly high temperatures. This can shorten the life of the oxygen probe.
  • 2. It is generally difficult to find a suitable installation point for the oxygen probe in the exhaust gas duct near the internal combustion engine, from which the exhaust gases of all cylinders of the internal combustion engine can be detected.

    • Diese Schwierigkeiten lassen sich umgehen, indem man die Sauerstoff-Sonde stromabwärts, d.h. weg von der Brennkraftmaschine, im Abgaskanal anbringt. Diese zweite Art der Montage wirft allerdings ein neues Problem auf. In der Anfangsphase nach Start der kalten Brennkraftmaschine ist der Abgaskanal stromauf der Sauerstoff-Sonde noch relativ kalt. Dadurch kommt es zur Kondensation des im Abgas enthaltenen Wassers. Werden die kondensierten Wassertröpfchen beispielsweise von der Wandung des Abgaskanals durch vorbeiströmende Abgase losgerissen und auf die Sauerstoff-Sonde geschleudert, so wird die Sauerstoff-Sonde an den Auftreffstellen lokal sehr rasch abgekühlt. Diese Abkühlung kann zu einer Beschädigung der Sauerstoff-Sonde, beispielsweise Risse in der Keramik, führen. Das Risiko der Beschädigung ist besonders hoch, wenn sich die Sauerstoff-Sonde schon auf einer hohen Temperatur befindet. Die Erfindung sieht vor, die Temperatur TSe der Sauerstoff-Sonde durch entsprechende Ansteuerung des Heizelements derart zu beeinflussen, daß das Risiko einer Beschädigung der Sauerstoff-Sonde durch auftreffendes Kondenswasser sehr gering gehalten werden kann.These difficulties can be avoided by using the oxygen probe downstream, i.e. away from the engine, im Exhaust duct attaches. However, this second type of assembly throws up a new problem. In the initial phase after the start of the cold The internal combustion engine is the exhaust duct upstream of the oxygen probe still relatively cold. This leads to condensation in the exhaust gas contained water. For example, the condensed water droplets from the wall of the exhaust duct through flowing Exhaust gases torn loose and thrown onto the oxygen probe, see above the oxygen probe becomes very fast locally at the impact points cooled down. This cooling can damage the oxygen probe, for example, cracks in the ceramic. The risk The damage is particularly high when the oxygen probe is already at a high temperature. The invention provides the temperature TSe of the oxygen probe by appropriate control to influence the heating element such that the risk of a Damage to the oxygen probe due to impinging condensation can be kept very low.

    Figur 1 zeigt eine schematische Darstellung einer Brennkraftmaschine 100 mit den erfindungswesentlichen Komponenten. An der Brennkraftmaschine 100 sind ein Ansaugtrakt 102 und ein Abgaskanal 104 angebracht. Im Ansaugtrakt 102 der Brennkraftmaschine 100 befinden sich - in Stromrichtung der angesaugten Luft gesehen - der Reihe nach ein Luftmassen- oder Luftmengenmesser 106, ein Sensor 108 zur Erfassung der Temperatur der angesaugten Luft und eine Einspritzdüse 110. Im Abgaskanal 104 der Brennkraftmaschine 100 befinden sich - in Stromrichtung der Abgase gesehen - eine Sauerstoff-Sonde 112 mit Heizelement 114, ein Sensor 116 zur Erfassung der Temperatur TAbg der Abgase oder der Wandung des Abgaskanals 104 in der Umgebung der Sauerstoff-Sonde 112, ein Katalysator 118 und optional eine weitere Sauerstoff-Sonde 120 mit Heizelement 122 und ein weiterer Sensor 124 zur Erfassung der Temperatur TAbg der Abgase oder der Wandung des Abgaskanals 104 in der Umgebung der Sauerstoff-Sonde 120. An der Brennkraftmaschine 100 ist ein Sensor 126 zur Erfassung der Kühlmitteltemperatur der Brennkraftmaschine 100 angebracht. Ein Steuergerät 128 ist über Zuleitungen mit dem Luftmassen- oder Luftmengenmesser 106 dem Sensor 108, der Einspritzdüse 110, der Sauerstoff-Sonde 112, dem Heizelement 114, dem Sensor 116, der Sauerstoff-Sonde 120, dem Heizelement 122, dem Sensor 124 und dem Sensor 126 verbunden.Figure 1 shows a schematic representation of an internal combustion engine 100 with the components essential to the invention. On the internal combustion engine 100, an intake tract 102 and an exhaust duct 104 are attached. Located in the intake tract 102 of the internal combustion engine 100 - viewed in the direction of flow of the intake air - one after the other Air mass or air flow meter 106, a sensor 108 for detection the temperature of the intake air and an injector 110. Im Exhaust gas duct 104 of internal combustion engine 100 is located in the flow direction of the exhaust gases - an oxygen probe 112 with a heating element 114, a sensor 116 for detecting the temperature TAbg of the exhaust gases or the wall of the exhaust duct 104 in the vicinity of the oxygen probe 112, a catalyst 118 and optionally another Oxygen probe 120 with heating element 122 and another sensor 124 for recording the temperature TAbg of the exhaust gases or the wall of the Exhaust gas duct 104 in the vicinity of the oxygen probe 120. At the Internal combustion engine 100 is a sensor 126 for detecting the coolant temperature of the engine 100 attached. A control unit 128 is via supply lines with the air mass or air flow meter 106 the sensor 108, the injection nozzle 110, the oxygen probe 112, the heating element 114, the sensor 116, the oxygen probe 120, the Heating element 122, the sensor 124 and the sensor 126 connected.

    Die Sauerstoff-Sonde 120 ist zur Regelung des Luft/Kraftstoff-Verhältnisses nicht unbedingt erforderlich, so daß heutige Systeme aus Kostengründen häufig nur mit der Sauerstoff-Sonde 112 ausgestattet sind. Für die Zukunft scheint ein Zwei-Sonden-Konzept, das sowohl die Sauerstoff-Sonde 112 als auch die Sauerstoff-Sonde 120 enthält, aber an Bedeutung zu gewinnen. Für die weiter unten folgende Beschreibung des Funktionsprinzips der Erfindung wird ein Ausführungsbeispiel mit nur einer Sauerstoff-Sonde 112 herangezogen. Die Übertragung auf ein Ausführungsbeispiel mit zwei Sauerstoff-Sonden 112 und 120 ist sehr einfach, da jedes Heizelement 114, 122 für sich nach dem gleichen Prinzip wie beim Ausführungsbeispiel mit nur einer Sauerstoff-Sonde 112 angesteuert wird. Eine getrennte Ansteuerung ist deshalb erforderlich, weil in der Regel davon auszugehen ist, daß die Sauerstoff-Sonden 112 und 120 unterschiedlichen Bedingungen ausgesetzt sind. Besonders groß können die Unterschiede nach einem Kaltstart der Brennkraftmaschine 100 sein. Dann besitzt der Katalysator 118 eine niedrige Temperatur - in der Regel ungefähr Umgebungstemperatur - und kann zunächst große Mengen an Kondenswasser speichern, so daß die Abgase auf dem Weg von der Sauerstoff-Sonde 112 zur Sauerstoff-Sonde 120 abgekühlt und mit Flüssigkeit angereichert werden. Die Gefahr der Beschädigung durch Kontakt mit Flüssigkeit besteht somit bei der Sauerstoff-Sonde 120 für einen wesentlich längeren Zeitraum als bei der Sauerstoff-Sonde 112, so daß die Schutzmaßnahmen für die Sauerstoff-Sonde 120 dementsprechend länger aufrecht zu erhalten sind.The oxygen probe 120 is used to regulate the air / fuel ratio not absolutely necessary, so today's systems are out Often only equipped with oxygen probe 112 due to cost reasons are. For the future, a two-probe concept appears to be both contains the oxygen probe 112 as well as the oxygen probe 120, but gain in importance. For the description below the principle of operation of the invention becomes an embodiment with only one oxygen probe 112. The Transfer to an embodiment with two oxygen probes 112 and 120 is very simple since each heating element 114, 122 is by itself on the same principle as in the embodiment with only one Oxygen probe 112 is controlled. A separate control is necessary because it can generally be assumed that that the oxygen probes 112 and 120 have different conditions are exposed. The differences can be particularly great after one Cold start of the internal combustion engine 100. Then the catalyst has 118 a low temperature - usually around ambient temperature - and can initially large amounts of condensation store so that the exhaust gases on their way from the oxygen probe 112 cooled to oxygen probe 120 and enriched with liquid become. The risk of damage from contact with liquid is therefore essential for the oxygen probe 120 longer period than with oxygen probe 112, so that the Protective measures for the oxygen probe 120 are accordingly longer are to be maintained.

    Im folgenden soll das Funktionsprinzip der Erfindung an Hand eines Ausführungsbeispiels mit nur einer Sauerstoff-Sonde 112 erläutert werden:In the following, the principle of operation of the invention will be described using a Exemplary embodiment with only one oxygen probe 112 explained become:

    Nach Starten der Brennkraftmaschine 100 wird zunächst ermittelt in welchem Betriebszustand sich die Brennkraftmaschine 100 befindet. Es wird zwischen zwei Betriebszuständen unterschieden:After starting the internal combustion engine 100, it is first determined in which operating state the internal combustion engine 100 is in. It a distinction is made between two operating states:

    In einem ersten Betriebszustand ist davon auszugehen, daß im Abgaskanal 104 in der Umgebung der Sauerstoff-Sonde 112 Flüssigkeit, in der Regel Kondenswasser vorhanden ist. In einem zweiten Betriebszustand ist davon auszugehen, daß im Abgaskanal 104 in der Umgebung der Sauerstoff-Sonde 112 keine Flüssigkeit vorhanden ist. Eine Gefahr der Beschädigung der Sauerstoff-Sonde 112 durch Kontakt mit Flüssigkeit besteht somit nur beim ersten Betriebszustand und folglich sind auch nur während des ersten Betriebszustands Maßnahmen zum Schutz der Sauerstoff-Sonde 112 zu treffen.In a first operating state it can be assumed that in the exhaust duct 104 in the vicinity of the oxygen probe 112 liquid, in condensation is usually present. In a second operating state it can be assumed that in the exhaust duct 104 in the area there is no liquid in the oxygen probe 112. A danger damage to oxygen probe 112 from contact with Liquid is therefore only in the first operating state and consequently are only measures during the first operating state Protection of the oxygen probe 112.

    Der erste Betriebszustand liegt in der Regel nach einem Kaltstart der Brennkraftmaschine 100 vor, solange die Temperatur TAbg des Abgaskanals in der Umgebung der Sauerstoff-Sonde 112 niedriger ist als die Taupunkt-Temperatur TTau von ca. 50 - 60 °C. Der Zeitraum, innerhalb dessen sich die Brennkraftmaschine im ersten Betriebszustand befindet, wird im folgenden als Phase I bezeichnet. Wird die Taupunkt-Temperatur TTau überschritten, so erfolgt ein Übergang zum zweiten Betriebszustand und es beginnt eine Phase II.The first operating state is usually after a cold start the internal combustion engine 100 as long as the temperature TAbg of the exhaust gas duct in the vicinity of the oxygen probe 112 is lower than the dew point temperature TTau of approx. 50 - 60 ° C. The period within which is the internal combustion engine in the first operating state is referred to as Phase I below. Will the dew point temperature TTau exceeded, there is a transition to second operating state and a phase II begins.

    Um zu ermitteln ob ein Kaltstart vorliegt, wird unmittelbar vor oder unmittelbar nach Starten der Brennkraftmaschine 100 das Signal des Sensors 126, der die Temperatur des Kühlmittels der Brennkraftmaschine 100 erfaßt, ausgewertet. Ergibt die Auswertung, daß die Temperatur des Kühlmittels größer ist als ein Schwellwert TKM1, der beispielsweise 75° C beträgt, so liegt kein Kaltstart vor. Die Brennkraftmaschine 100 befindet sich im zweiten Betriebszustand und es sind keine weitergehenden Maßnahmen zum Schutz der Sauerstoff-Sonde 112 vor Beschädigung durch Kontakt mit Flüssigkeit erforderlich, d.h. die Ansteuerung des Heizelemets 114 unterliegt in diesem Zusammenhang keinen Beschränkungen. Ist die Temperatur des Kühlmittels dagegen kleiner als der Schwellwert TKM1, so liegt ein Kaltstart vor und es ist zunächst davon auszugehen, daß sich die Brennkraftmaschine 100 im ersten Betriebszustand befindet. Demgemäß sind solange Maßnahmen zum Schutz der Sauerstoff-Sonde 112 zu treffen, bis der zweite Betriebszustand erreicht ist. Diese Maßnahmen sollen jeweils verhindern, daß die Sauerstoff-Sonde 112 durch das Heizelement 114 während der Phase I auf Temperaturen geheizt wird, bei dem die Gefahr einer Beschädigung der Sauerstoff-Sonde 112 durch Kontakt mit Flüssigkeit besteht. Im einzelnen stehen folgende Maßnahmen zur Verfügung: To determine whether there is a cold start, immediately before or immediately after starting the engine 100, the signal of Sensor 126, which is the temperature of the coolant of the internal combustion engine 100 recorded, evaluated. If the evaluation shows that the Temperature of the coolant is greater than a threshold TKM1, the For example, if it is 75 ° C, there is no cold start. The Internal combustion engine 100 is in the second operating state and there are no further measures to protect the oxygen probe 112 required before damage due to contact with liquid, i.e. the control of the heating element 114 is subject to FIG no restrictions in this context. Is the temperature of the Coolant, on the other hand, is less than the threshold value TKM1 Cold start before and it can initially be assumed that the Internal combustion engine 100 is in the first operating state. Accordingly measures to protect the oxygen probe 112 must be taken as long as until the second operating state is reached. These measures are intended to prevent the oxygen probe 112 from the Heating element 114 is heated to temperatures during phase I, in which there is a risk of damage to the oxygen probe 112 There is contact with liquid. The following measures are available to disposal:

    Maßnahme 1:Measure 1:

    Das Heizelement 114 bleibt ausgeschaltet.The heating element 114 remains switched off.

    Maßnahme 2:Measure 2:

    Das Heizelement 114 wird mit gegenüber seiner Nennleistung P1 reduzierter Leistung P2 betrieben.The heating element 114 is reduced with respect to its nominal power P1 Power P2 operated.

    Maßnahme 3:Measure 3:

    Das Heizelement 114 wird anfangs mit seiner Nennleistung P1 betrieben und dann, wenn davon auszugehen ist, daß die Temperatur TSe der Sauerstoff-Sonde 112 einen Schwellwert TSel überschritten hat, wird die Heizleistung P derart reduziert, daß die Temperatur TSe der Sauerstoff-Sonde 112 nicht mehr oder nur noch geringfügig steigt. Der Schwellwert TSel liegt ca. 50 K unterhalb einer kritischen Temperatur TSeK von z. B. 300 bis 350° C, oberhalb derer die Gefahr der Beschädigung der Sauerstoff-Sonde 112 bei Kontakt mit Flüssigkeit besteht. Die Temperatur TSe der Sauerstoff-Sonde 112 kann aus der Zeit, die seit dem Einschalten des Heizelements 114 verstrichen ist, abgeschätzt werden oder aus den Ausgangssignalen der Sauerstoff-Sonde 112 oder aus den Signalen eines Temperatursensors, der sich in thermischen Kontakt mit der Sauerstoff-Sonde 112 befindet oder nach anderen dem Fachmann geläufigen Verfahren ermittelt werden.The heating element 114 is initially operated at its nominal power P1 and then if it can be assumed that the temperature TSe the Oxygen probe 112 has exceeded a threshold TSel the heating power P is reduced such that the temperature TSe Oxygen probe 112 no longer rises or only rises slightly. The threshold TSel is approx. 50 K below a critical one Temperature TSeK of z. B. 300 to 350 ° C, above which the danger damage to oxygen probe 112 upon contact with liquid consists. The temperature TSe of the oxygen probe 112 can be off the time that has passed since the heating element 114 was switched on is estimated or from the output signals of the oxygen probe 112 or from the signals of a temperature sensor, the is in thermal contact with oxygen probe 112 or determined by other methods familiar to the person skilled in the art.

    Der Zeitpunkt, zu dem Phase I endet und Phase II beginnt, kann entweder aus Erfahrungswerten, die während der Applikation gesammelt wurden, näherungsweise festgelegt werden (Möglichkeit 1) oder folgendermaßen ermittelt werden:The time when phase I ends and phase II begins can either from empirical values collected during the application were determined approximately (option 1) or as follows be determined:

    Möglichkeit 2:Possibility 2:

    Aus den Signalen des Temperatursensors 116 wird ermittelt ob die Taupunkt-Temperatur TTau in der Umgebung der Sauerstoff-Sonde 112 überschritten ist. From the signals of the temperature sensor 116 it is determined whether the Dew point temperature TTau in the vicinity of the oxygen probe 112 is exceeded.

    Möglichkeit 3:Option 3:

    Aus einem mathematischen Model für die Abgastemperatur, in das die seit Starten der Brennkraftmaschine 100 aufsummierte Luftmenge bzw. Luftmasse eingeht, wird ermittelt, ob die Taupunkt-Temperatur TTau in der Umgebung der Sauerstoff-Sonde 112 überschritten ist.From a mathematical model for the exhaust gas temperature, into which the since the start of the internal combustion engine 100, the total air volume or Air mass comes in, it is determined whether the dew point temperature TTau in the vicinity of the oxygen probe 112 is exceeded.

    Denkbar wäre auch der Einsatz eines Feuchtigkeitssensors in der Umgebung der Sauerstoff-Sonde 112, um zu ermitteln, ob der erste oder der zweite Betriebszustand der Brennkraftmaschine 100 vorliegt. Im Augenblick kommt dieser Variante aus Kostengründen noch keine große Bedeutung zu. Dies könnte sich im Laufe der technischen Entwicklung aber durchaus ändern.The use of a moisture sensor in the environment would also be conceivable oxygen probe 112 to determine whether the first or the second operating state of internal combustion engine 100 is present. in the At the moment, this variant is not a big one for cost reasons Meaning too. This could change in the course of technical development but definitely change.

    Figur 2 zeigt ein Flußdiagramm eines bevorzugten Ausführungsbeispiels des erfindungsgemäßen Systems zum Betreiben des Heizelements 114 einer Sauerstoff-Sonde 112. Bei diesem Ausführungsbeispiel wird während der Phase I die obenbeschriebene Maßnahme 3 ergriffen und der Übergang von Phase I nach Phase II wird gemäß einer der obenbeschriebenen Möglichkeiten 1, 2 oder 3 ermittelt.Figure 2 shows a flow diagram of a preferred embodiment of the system according to the invention for operating the heating element 114 of an oxygen probe 112. In this embodiment during phase I, measure 3 described above and the transition from phase I to phase II is according to one of those described above Possibilities 1, 2 or 3 determined.

    Das Flußdiagramm beginnt mit einem ersten Schritt 200, in dem die Brennkraftmaschine 100 gestartet wird. Anschließend wird in einem Schritt 202 abgefragt, ob die Kühlmittelttemperatur der Brennkraftmaschine 100 kleiner ist als der Schwellwert TKMI. Ist diese Bedingung erfüllt, so schließt sich ein Schritt 204 an. Im Schritt 204 wird das Heizelement 114 mit Nennleistung P1 in Betrieb genommen. Danach wird in Schritt 206 abgefragt, ob die Temperatur TSe der Sauerstoff-Sonde 112 den Schwellwert TSel überschritten hat. Diese Abfrage wird solange wiederholt, bis die abgefragte Bedingung erfüllt ist. Ist die Bedingung erfüllt, so folgt Schritt 208. In Schritt 208 wird abgefragt, ob davon auszugehen ist, daß Flüssigkeit in der Umgebung der Sauerstoff-Sonde 112 vorhanden ist. Zur Beantwortung dieser Frage wird wenigstens eine der drei obengenannten Möglichkeiten 1, 2 oder 3 herangezogen. Ist die Bedingung 208 erfüllt, so schließt sich ein Schritt 210 an, in dem veranlaßt wird, daß das Heizelement 114 mit relativ zu seiner Nennleistung P1 reduzierter Leistung P2 betrieben wird. Die Reduzierung der Leistung P läßt sich beispielsweise durch Takten des durch das Heizelement 114 fließenden elektrischen Stroms erreichen. Auf Schritt 210 folgt wieder Schritt 208. Ist Bedingung 208 nicht erfüllt, so folgt Schritt 212, in dem veranlaßt wird, daß das Heizelement 114 mit Nennleistung P1 betrieben wird. Zu Schritt 212 kann man auch direkt von Schritt 202 aus gelangen, und zwar dann, wenn die Bedingung des Schrittes 202 nicht erfüllt ist, d.h. wenn kein Kaltstart vorliegt und somit auch keine Maßnahmen zum Schutz der Sauerstoff-Sonde 112 vor Beschädigung durch Kontakt mit Flüssigkeit erforderlich sind.The flow chart begins with a first step 200, in which the Internal combustion engine 100 is started. Then in one Step 202 queries whether the engine coolant temperature 100 is less than the threshold value TKMI. Is this condition a step 204 follows. In step 204 the heating element 114 is put into operation with the nominal power P1. Then in step 206 it is queried whether the temperature TSe Oxygen probe 112 has exceeded the threshold TSel. This The query is repeated until the queried condition is met is. If the condition is met, step 208 follows Step 208 asks whether it is to be assumed that liquid is present in the vicinity of the oxygen probe 112. To answer This question will address at least one of the three above Options 1, 2 or 3 used. If condition 208 is met, this is followed by a step 210 in which it is caused that the heating element 114 is reduced with respect to its nominal power P1 Power P2 is operated. The reduction in power P can, for example, be clocked by the heating element 114 flowing electrical current. Step 210 follows again Step 208. If condition 208 is not met, step follows 212, in which the heating element 114 is caused to run at nominal power P1 is operated. You can also go to step 212 directly from step 202 come out when the condition of the step 202 is not satisfied, i.e. if there is no cold start and thus also no measures to protect the oxygen probe 112 from damage due to contact with liquid are required.

    Figur 3 zeigt Diagramme für den zeitlichen Verlauf der dem Heizelement 114 zugeführten elektrischen Leistung P (oben), der Temperatur TSe der Sauerstoff-Sonde 112 (Mitte) und der Temperatur TAbg in der Umgebung der Sauerstoff-Sonde 112 (unten). Die Zeitskala der Abszisse beginnt bei jedem der drei Diagramme mit dem Starten der Brennkraftmaschine 100 oder mit dem Einschalten des Heizelements 114 bei t = t0. Die weiter oben bereits näher definierte Phase I ist in zwei Teilphasen unterteilt. Eine Teilphase Ia und eine sich anschließende Teilphase Ib. An Teilphase Ib schließt sich Phase II an. Die einzelnen Phasen bzw. Teilphasen sind durch vertikale gestrichelte Linien voneinander getrennt.Figure 3 shows diagrams for the time course of the heating element 114 supplied electrical power P (top), the temperature TSe of the oxygen probe 112 (middle) and the temperature TAbg in the Environment of the oxygen probe 112 (below). The time scale of the abscissa begins with each of the three diagrams when the internal combustion engine is started 100 or when the heating element 114 is switched on t = t0. Phase I, which has already been defined further above, is in two Sub-phases divided. A sub-phase Ia and a subsequent one Sub-phase Ib. Phase II follows on from phase Ib. The single ones Phases or sub-phases are by vertical dashed lines separated from each other.

    Sämtliche Kurvenverläufe der Figur 3 beschreiben den Fall, bei dem die Kühlmitteltemperatur der Brennkraftmaschine 100 unmittelbar vor oder unmittelbar nach dem Start der Brennkraftmaschine 100 unterhalb des Schwellwerts TKM1 liegt, d.h. es liegt ein Kaltstart vor. Bezieht man sich auf das in Figur 2 dargestellte Flußdiagramm, so bedeutet dies, daß die in Schritt 202 abgefragte Bedingung erfüllt ist. Folglich wird entsprechend Schritt 204 des Flußdiagramms der Figur 2 das Heizelement 114 zunächst mit Nennleistung P1 betrieben, beispielsweise 18 W. Dies kann aus dem oberen Diagramm der Figur 3 abgelesen werden, bei dem auf der Ordinate die dem Heizelement 114 zugeführte elektrische Leistung P aufgetragen ist. Während der Teilphase Ia liegt die elektrische Leistung P konstant beim Wert P1.All curves of Figure 3 describe the case in which the coolant temperature of the engine 100 immediately before or immediately after the start of the internal combustion engine 100 below of the threshold value TKM1, i.e. there is a cold start. Relates if one refers to the flow diagram shown in FIG. 2, it means this means that the condition queried in step 202 is fulfilled is. Thus, according to step 204 of the flow chart, the FIG. 2, the heating element 114 is initially operated with nominal power P1, for example 18 W. This can be seen from the upper diagram in FIG. 3 can be read in which on the ordinate the heating element 114 supplied electrical power P is plotted. During the sub-phase The electrical power P is generally constant at the value P1.

    Im mittleren Diagramm der Figur 3 ist auf der Ordinate die Temperatur TSe der Sauerstoff-Sonde 112 aufgetragen. Innerhalb der Teilphase Ia ist ein Anstieg der Temperatur TSe ab der Zeit t = t0 als Folge der Beheizung durch das Heizelement 114 zu erkennen. Der Temperaturanstieg wird zusätzlich durch das an der Sauerstoff-Sonde 112 vorbeistreichende Abgas beeinflußt.In the middle diagram in FIG. 3, the temperature is on the ordinate TSe of the oxygen probe 112 plotted. Within the sub-phase Ia is an increase in temperature TSe from time t = t0 as a result the heating by the heating element 114 to recognize. The rise in temperature is additionally achieved by the oxygen sensor 112 passing exhaust affects.

    Im unteren Diagramm der Figur 3 ist auf der Ordinate die Temperatur TAbg des Abgases bzw. des Abgaskanals 104 aufgetragen. Die Temperatur TAbg steigt zunächst ab der Zeit t = t0 stark an und strebt dann gegen Ende der Teilphase Ia einem konstanten Wert von ca. 50 bis 60° C zu, also etwa der Taupunkt-Temperatur TTau.In the lower diagram in FIG. 3, the temperature is on the ordinate TAbg of the exhaust gas or the exhaust gas duct 104 is plotted. The temperature TAbg initially rises sharply from time t = t0 and then strives towards the end of sub-phase Ia a constant value of approx. 50 to 60 ° C, i.e. about the dew point temperature TTau.

    Der Endpunkt der Teilphase Ia ist dann erreicht, wenn die Temperatur TSe der Sauerstoff-Sonde 112 den Schwellwert TSel, beispielsweise 250 bis 300° C, überschreitet. Im Flußdiagramm der Figur 2 ist das der Fall, wenn die Bedingung der Abfrage 206 erstmals erfüllt ist. Zu diesem Zeitpunkt endet die Teilphase Ia und es beginnt die Teilphases Ib. Die elektrische Leistung P, mit der das Heizelement 114 beaufschlagt wird, wird auf einen reduzierten Wert P2, beispielsweise 11 W, abgesenkt (siehe Figur 3, oberes Diagramm). Die Reduzierung der elektrischen Leistung P hat zur Folge, daß die Temperatur TSe der Sauerstoff-Sonde 112 einen annähernd konstanten Wert annimmt (siehe Figur 3, mittleres Diagramm). The end point of phase Ia is reached when the temperature TSe of the oxygen probe 112, the threshold TSel, for example 250 to 300 ° C. In the flow chart of Figure 2 that is the case when the condition of query 206 is met for the first time. At this point the sub-phase Ia ends and the sub-phase begins Ib. The electrical power P with which the heating element 114 is applied to a reduced value P2, for example 11 W, lowered (see Figure 3, upper diagram). The reduction the electrical power P has the consequence that the temperature TSe the oxygen probe 112 assumes an approximately constant value (see Figure 3, middle diagram).

    Der Zeitpunkt des Übergangs von Teilphase Ib nach Phase II ergibt sich aus dem zeitlichen Verlauf der Temperatur TAbg. Die Temperatur TAbg in der Umgebung der Sauerstoff-Sonde 112 ist nach einem Anstieg ab der Zeit t = t0 für einen größeren Zeitraum in den Teilphasen Ia und Ib annähernd konstant und beträgt ca. 50 bis 60° C, was ungefähr der Taupunkt-Temperatur TTau entspricht. TAbg verharrt auf diesem Wert, bis die Flüssigkeit im Abgaskanal 104 in der Umgebung der Sauerstoff-Sonde 112 und stromaufwärts vollständig in den gasförmigen Zustand übergegangen ist. Der Anstieg der Temperatur TAbg gegen Ende der Teilphase Ib weist somit darauf hin, daß in der Umgebung der Sauerstoff-Sonde 112 keine Flüssigkeit mehr vorhanden ist. Aus diesem Grund fällt der Zeitpunkt für den Übergang von Teilphase Ib nach Phase II mit einem Anstieg der Temperatur TAbg über die Taupunkt-Temperatur TTau zusammen.The time of transition from sub-phase Ib to phase II results derive from the time course of the temperature TAbg. The temperature TAbg in the vicinity of oxygen probe 112 is after an increase from time t = t0 for a longer period in sub-phases Ia and Ib approximately constant and is approximately 50 to 60 ° C, which is approximately corresponds to the dew point temperature TTau. TAbg remains on this Value until the liquid in the exhaust duct 104 in the vicinity of the Oxygen probe 112 and completely upstream in the gaseous Condition has passed. The rise in temperature TAbg against End of sub-phase Ib thus indicates that in the area there is no more liquid in the oxygen probe 112. Out for this reason the time for the transition from sub-phase Ib falls after phase II with an increase in temperature TAbg above the dew point temperature Tau together.

    Aus dem oberen Diagramm der Figur 3 kann man entnehmen, daß mit Beginn der Phase II die elektrische Leistung P, mit der das Heizelement 114 beaufschlagt wird, von P2 auf P1 erhöht wird. Dies entspricht dem Schritt 212 des Flußdiagramms aus Figur 2, der dann ausgeführt wird, wenn die in Schritt 208 abgefragte Bedingung nicht erfüllt ist. Wie aus dem mittleren Diagramm der Figur 3 zu sehen ist, hat die Erhöhung der elektrischen Leistung P eine Erhöhung der Temperatur TSe der Sauerstoff-Sonde 112 zur Folge.From the upper diagram in FIG. 3 it can be seen that with the beginning phase II is the electrical power P with which the heating element 114 is applied, is increased from P2 to P1. This matches with step 212 of the flow chart of Figure 2, which is then performed if the condition queried in step 208 is not met is. As can be seen from the middle diagram in FIG. 3, the increase in electrical power P has an increase in Temperature TSe of the oxygen probe 112 result.

    Das erfindungsgemäße System arbeitet umso zuverlässiger, je genauer die Zeitpunkte für den Übergang von Teilphase Ia nach Ib und für den Übergang von Teilphase Ib nach Phase II festgelegt werden können. Im folgenden wird anhand bevorzugter Ausführungsbeispiele dargelegt, wie man diese Zeitpunkte ermitteln kann.The system according to the invention works more reliably the more precisely the times for the transition from phase Ia to Ib and for the Transition from sub-phase Ib to phase II can be determined. in the The following is explained using preferred exemplary embodiments, how to determine these times.

    Die Eigenschaften keramischer Sensoren sind häufig temperaturabhängig, so daß die Temperatur TSe der Sensoren in diesen Fällen ohne zusätzliche Thermoelemente aus dem Verhalten der Sensoren ermittelt werden kann. Dies gilt auch für die hier beschriebene Sauerstoff-Sonde 112, deren elektrischer Widerstand mit steigender Temperatur stark abnimmt.The properties of ceramic sensors are often temperature-dependent, so that the temperature TSe of the sensors in these cases without additional thermocouples determined from the behavior of the sensors can be. This also applies to the oxygen probe described here 112, whose electrical resistance increases with temperature decreases sharply.

    Figur 4 zeigt eine an sich bekannte Schaltung, mit der aus dem elektrischen Widerstand der Sauerstoff-Sonde 112 ermittelt wird, ob die Sauerstoff-Sonde 112 einen Schwellwert TSel überschritten hat, d.h. die Schaltung dient dazu, den Zeitpunkt des Übergangs von Teilphase Ia nach Teilphase Ib zu ermitteln.Figure 4 shows a circuit known per se, from which electrical resistance of the oxygen probe 112 is determined whether the oxygen probe 112 has exceeded a threshold value TSel, i.e. the circuit serves the time of transition from Determine sub-phase Ia after sub-phase Ib.

    Als Ersatzschaltbild für die Sauerstoff-Sonde 120 (strichpunktiert gezeichnet) kann eine Reihenschaltung aus einer Spannungsquelle 400 und einem Widerstand 402 dienen. Parallel zu dieser Reihenschaltung ist ein Widerstand 404, z. B. 51 k0hm, geschaltet. Der Spannungsabfall am Widerstand 404, der ein Bestandteil des Steuergeräts 128 (strichpunktiert gezeichnet) ist, wird erfaßt und ausgewertet, was durch einen Spannungsmeser 406 angedeutet ist. Die Sauerstoff-Sonde 112 besitzt im kalten Zustand einen Widerstand 402 von etwa 10 M0hm und im heißen Zustand von etwa 50 0hm. Die am Widerstand 404 abfallende Spannung hängt vom Widerstand 402 der Sauerstoff-Sonde 112 ab und ermöglicht somit Rückschlüsse auf die Temperatur TSe der Sauerstoff-Sonde 112.As an equivalent circuit diagram for the oxygen probe 120 (dot-dash line a series connection from a voltage source 400 and serve a resistor 402. Parallel to this series connection is a resistor 404, e.g. B. 51 k0hm switched. The voltage drop at resistor 404, which is a component of control unit 128 (dash-dotted) is recorded and evaluated what is indicated by a voltage meter 406. The oxygen probe 112, when cold, has a resistance 402 of approximately 10 Mohm and in the hot state of about 50 0hm. The one falling at resistor 404 Voltage depends on the resistance 402 of the oxygen probe 112 and thus allows conclusions to be drawn about the temperature TSe of the oxygen probe 112.

    Neben der Widerstandsänderung tritt bei Temperaturerhöhung der Sauerstoff-Sonde 112 ein weiterer Effekt auf. In der Regel liefert die Sauerstoff-Sonde 112 bereits unterhalb der kritischen Temperatur TSeK eine Spannung, die vom Sauerstoffgehalt des Abgases abhängt, beispielsweise ab Überschreiten des Schwellwerts TSel. Somit existiert in der Regel ein Temperaturbereich, in dem die Sauerstoff-Sonde 112 betriebsbereit ist ohne daß eine nennenswerte Ge-ahr einer Beschädigung bei Kontakt mit Flüssigkeit besteht. In addition to the change in resistance, when the temperature rises the Oxygen probe 112 has another effect. Usually delivers the oxygen probe 112 is already below the critical temperature TSeK a voltage that depends on the oxygen content of the exhaust gas, for example, when the threshold TSel is exceeded. So there is usually a temperature range in which the oxygen probe 112 is ready for operation without any noteworthy warning there is damage on contact with liquid.

    Folglich besteht bereits in der Anfangsphase nach dem Kaltstart (Phase I) die Möglichkeit, die Sauerstoff-Sonde 112 auf Betriebstemperatur zu bringen und somit eine Regelung des Luft/Kraftstoff-Verhältnisses zu ermöglichen, ohne daß die Gefahr einer Beschädigung der Sauerstoff-Sonde 112 durch Kontakt mit Flüssigkeit in Kauf genommen werden muß, d.h. die Sauerstoff-Sonde wird in diesem Fall im Temperaturbereich zwischen dem Schwellwert TSel und der kritischen Temperatur TSeK betrieben. Die nach Motorstart frühestmögliche Inbetriebnahme der Sauerstoff-Sonde 112 ist im Sinne einer möglichst geringen Schadstoffemission dringend erwünscht. Eine weitere Erhöhung der Temperatur TSe der Sauerstoff-Sonde 112 in Phase II ist trotzdem erforderlich, da die Sauerstoff-Sonde 112 bei höheren Temperaturen viele funktionelle Vorteile aufweist.Consequently, there is already in the initial phase after the cold start (Phase I) the possibility of oxygen probe 112 at operating temperature bring and thus a regulation of the air / fuel ratio to enable without the risk of damage the oxygen probe 112 by contact with liquid in Purchase must be made, i.e. the oxygen probe is in this Fall in the temperature range between the threshold TSel and the critical Temperature operated TSeK. The earliest possible after starting the engine Putting the oxygen probe 112 into operation is as possible low pollutant emissions are urgently desired. Another Increase in temperature TSe of oxygen probe 112 in phase II nevertheless required because the oxygen probe 112 is at higher Temperatures has many functional advantages.

    Der Zeitpunkt des Übergangs von Teilphase Ib nach Phase II läßt sich mit dem folgenden Verfahren auch ohne den Temperatursensor 116 ermitteln, d. h. der Temperatursensor 116 ist für das erfindungsgemäße System nicht unbedingt erforderlich und kann auch entfallen. Dann wird mittels eines Modells, das den Temperaturverlauf der Abgase nachbildet, ermittelt, wann die Abgase die Taupunkt-Temperatur TTau überschritten haben. Als Eingangsgröße wird die vom Luftmassen- oder Luftmengenmesser 106 erfaßte Luftmasse oder Luftmenge in das Modell eingespeist. Im Modell wird die Luftmasse oder Luftmenge aufintegriert und das Integral wird mit einem empirisch ermittelten Schwellwert verglichen. Der Schwellwert stellt die von der Brennkraftmaschine 100 seit dem Kaltstart insgesamt angesaugte Luftmasse oder Luftmenge dar, bei der die Temperatur TAbg erfahrungsgemäß die Taupunkt-Temperatur TTau übersteigt. Sobald der im Rahmen des Modells durchgeführte Vergleich ergibt, daß der Schwellwert erreicht ist, ist davon auszugehen, daß die Temperatur TAbg die Taupunkt-Temperatur TTau überschritten hat. The time of transition from phase Ib to phase II can be determine without the temperature sensor 116 using the following method, d. H. the temperature sensor 116 is for the invention System not absolutely necessary and can also be omitted. Then is using a model that shows the temperature profile of the exhaust gases simulates when the exhaust gases reach the dew point temperature TTau have exceeded. The input variable is that of air mass or Airflow meter 106 senses air mass or airflow into the model fed. The air mass or air volume is integrated in the model and the integral is determined empirically with one Threshold compared. The threshold value represents that of the internal combustion engine 100 air masses sucked in since the cold start or the amount of air at which the temperature TAbg is known to be the Dew point temperature exceeds TTau. Once the under the model carried out comparison shows that the threshold reached , it can be assumed that the temperature TAbg is the dew point temperature TTau has exceeded.

    Bei der empirischen Ermittlung des Schwellwerts für die aufintegrierte Luftmasse oder Luftmenge während der Applikationsphase ist zu beachten, für welchen Abschnitt des Abgaskanals 104 das Modell angewendet werden soll. So ist der Schwellwert für die Umgebung der Sauerstoff-Sonde 120 wesentlich größer als der Schwellwert für die Umgebung der Sauerstoff-Sonde 112. Der Unterschied wird im wesentlichen dadurch hervorgerufen, daß im Falle der Sauerstoff-Sonde 120 den Abgasen große Wärmeenergiemengen zur Aufheizung des Katalysators 118 entzogen werden und damit ein Verdunsten des im Katalysator 118 anfallenden Kondenswassers 118 verzögert wird. Erst wenn das Kondenswasser stromauf der Sauerstoff-Sonde 120 vollständig verdunstet ist, steigt die Temperatur TAbg des Abgases in der Umgebung der Sauerstoff-Sonde 120 über die Taupunkt-Temperatur TTau an.In the empirical determination of the threshold for the integrated Air mass or air volume during the application phase note for which section of the exhaust duct 104 the model should be applied. So is the threshold for the environment of the Oxygen probe 120 much larger than the threshold for that Environment of the oxygen probe 112. The difference is essentially caused by the fact that in the case of the oxygen probe 120 large amounts of heat energy for heating the catalytic converter 118 are withdrawn and thus evaporation of the catalyst 118 accumulating condensate 118 is delayed. Only when the condensed water completely evaporated upstream of the oxygen probe 120 is the temperature TAbg of the exhaust gas in the vicinity of the Oxygen probe 120 on the dew point temperature TTau.

    Im Rahmen des erfindungsgemäßen Systems ist es auch möglich, das Heizelement 114 schon vor dem Start der Brennkraftmaschine 100 in Betrieb zu nehmen. In diesem Zusammenhang wird die Inbetriebnahme durch einen Vorgang ausgelöst, der zeitlich vor dem Start der Brennkraftmaschine 100 liegt, beispielsweise Öffnen der Fahrzeugtür, Einschalten der Innenraumbeleuchtung, Betätigung des Gurtschlosses oder Belastung des Fahrersitzes. Dadurch läßt sich die Zeit zwischen dem Start der Brennkraftmaschine 100 und der Betriebsbereitschaft der Sauerstoff-Sonde 112 verkürzen, was z. B. in Zusammenhang mit einem beheizbaren Katalysator wichtig sein kann. Auch bei dieser Variante können die geschilderten Maßnahmen zum Schutz der Sauerstoff-Sonde 112 eingesetzt werden.In the context of the system according to the invention, it is also possible that Heating element 114 even before the engine 100 starts To take operation. In this context, the commissioning triggered by a process that occurs before the start of the internal combustion engine 100 lies, for example opening the vehicle door, switching on the interior lighting, actuation of the belt buckle or Driver seat load. This allows the time between Start of the internal combustion engine 100 and the operational readiness of the Shorten oxygen probe 112, which z. B. in connection with a heated catalyst can be important. This variant too can the described measures to protect the oxygen probe 112 can be used.

    Die Temperatur TAbg repräsentiert die Temperatur in der Umgebung der Sauerstoff-Sonde 112 bzw. 120. Je nach Ausführungsbeispiel kann es sich dabei um die Temperatur der Abgase, der Wandung des Abgaskanals 104 oder des Katalysators 118 handeln. Falls die Möglichkeit besteht, mehrere dieser Temperaturen zu erfassen, kann TAbg auch durch Mittelung über wenigstens zwei dieser Temperaturen ermittelt werden. The temperature TAbg represents the temperature in the vicinity of the Oxygen probe 112 or 120. Depending on the embodiment, it can the temperature of the exhaust gases, the wall of the exhaust duct 104 or the catalyst 118 act. If there is a possibility TAbg can also record several of these temperatures by Averaging over at least two of these temperatures can be determined.

    Statt der Kühlmitteltemperatur kann auch die Temperatur der Wandung des Abgaskanals (104) oder die Temperatur des Katalysators (118) herangezogen werden, um zu ermitteln, ob ein Kaltstart der Brennkraftmaschine (100) vorliegt. Voraussetzung dafür ist allerdings, daß ein entsprechender Temperatursensor vorhanden ist. Falls beim Start der Brennkraftmaschine (100) die von diesem Sensor erfaßte Temperatur kleiner ist als die Taupunkttemperatur (TTau), liegt ein Kaltstart vor.Instead of the coolant temperature, the temperature of the wall can also be changed of the exhaust duct (104) or the temperature of the catalyst (118) can be used to determine whether a cold start of the internal combustion engine (100) is present. However, the prerequisite for this is that a corresponding temperature sensor is available. If at Start of the internal combustion engine (100) that detected by this sensor Temperature is lower than the dew point temperature (TTau) Cold start before.

    Claims (12)

    1. System for operating a heating element (114) of a ceramic sensor (112), which is fitted in the exhaust pipe (104) of an internal combustion engine (100) and can be heated up by the heating element (114),
      characterized by
      means which activate the heating element (114) as a function of the operating state of the internal combustion engine,
      means for establishing a first operating state (phase I) whenever, when starting the internal combustion engine (100), the coolant temperature is below a threshold value (TKM1) or if the temperature (TAbg) of the exhaust system is below a threshold value (TTau),
      means for establishing a second operating state, which comprises the operating points outside the first operating state,
      and means which do not put the heating element into operation, or activate the heating element (114) in such a way that the ceramic sensor (112) is operated below a critical temperature (TSeK) when the internal combustion engine is in the first operating state (phase I).
    2. System according to Claim 1, characterized in that the heating element (114) of the ceramic sensor (112) is operated with reduced power (P2) during the first operating state (phase I) of the internal combustion engine (100).
    3. System according to Claim 1, characterized in that, during the first operating state (phase I) of the internal combustion engine (100), the heating element (114) of the ceramic sensor (112) is operated initially (subphase Ia) with high power (P1) and subsequently (subphase Ib) with reduced power (P2), the transition from high power (P1) to reduced power (P2) taking place when a selectable time period has elapsed since the starting of the internal combustion engine (100) or if it is to be assumed that the temperature (TSe) of the ceramic sensor (112) has exceeded a threshold value (TSe1).
    4. System according to Claim 3, characterized in that it is determined from the temperature-dependent properties of the ceramic sensor (112) or from the signal of a temperature sensor in thermal contact with the ceramic sensor (112) whether the temperature (TSe) of the ceramic sensor (112) has exceeded the threshold value (TSe1).
    5. System according to one of the preceding claims, characterized in that a transition from the first operating state (phase I) to the second operating state (phase II) of the internal combustion engine (100) takes place when a selectable time period has elapsed since the beginning of the first operating state (phase I).
    6. System according to one of the preceding claims, characterized in that the transition from the first operating state (phase I) to the second operating state (phase II) of the internal combustion engine (100) takes place if it can be assumed that the temperature (TAbg) of the exhaust system has exceeded a threshold value (TTau) in the vicinity of the ceramic sensor (112).
    7. System according to Claim 6, characterized in that it is determined from the signal of a temperature sensor which is fitted in the vicinity of the ceramic sensor or from a model which describes in approximation the temperature (TAbg) in the vicinity of the ceramic sensor whether the temperature (TAbg) in the vicinity of the ceramic sensor (112) has exceeded the threshold value (TTau).
    8. System according to Claim 7, characterized in that in the model the amount of air or mass of air sucked in since the starting of the internal combustion engine (110) is integrated and the integral is compared with a threshold value.
    9. System according to one of the preceding claims, characterized in that the critical temperature (TSeK) is selected such that, when the ceramic sensor (112) is operated below the critical temperature (TSeK), there is no appreciable risk of damage to the ceramic sensor (112) on contact with liquid.
    10. System according to one of the preceding claims, characterized in that the ceramic sensor (112) is operated during the first operating state (phase I) of the internal combustion engine (100) in the temperature range between the threshold value (TSel), above which the ceramic sensor (112) is at least conditionally operational, and the critical temperature (TSeK).
    11. System according to one of the preceding claims, characterized in that the heating element (114) of the ceramic sensor (112) can be switched on in response to an occurrence at a time before the starting of the internal combustion engine (100).
    12. System according to one of the preceding claims, characterized in that the ceramic sensor (112) is an oxygen probe which is arranged in the exhaust pipe (104) of the internal combustion engine (100), before or after a catalytic converter (118), seen in the direction of flow of the exhaust gases.
    EP94900746A 1993-01-12 1993-12-02 System for operating a heating element for a ceramic sensor in a motor vehicle Expired - Lifetime EP0635148B1 (en)

    Applications Claiming Priority (3)

    Application Number Priority Date Filing Date Title
    DE4300530 1993-01-12
    DE4300530A DE4300530C2 (en) 1993-01-12 1993-01-12 System for operating a heating element for a ceramic sensor in a motor vehicle
    PCT/DE1993/001149 WO1994016371A1 (en) 1993-01-12 1993-12-02 System for operating a heating element for a ceramic sensor in a motor vehicle

    Publications (2)

    Publication Number Publication Date
    EP0635148A1 EP0635148A1 (en) 1995-01-25
    EP0635148B1 true EP0635148B1 (en) 1999-03-17

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    EP94900746A Expired - Lifetime EP0635148B1 (en) 1993-01-12 1993-12-02 System for operating a heating element for a ceramic sensor in a motor vehicle

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    EP (1) EP0635148B1 (en)
    JP (1) JP3464221B2 (en)
    KR (1) KR100261930B1 (en)
    DE (2) DE4300530C2 (en)
    WO (1) WO1994016371A1 (en)

    Cited By (4)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    DE102008040593A1 (en) 2008-03-03 2009-09-10 Robert Bosch Gmbh Method for determining measure of water entry into exhaust duct of internal combustion engine, involves determining measure of water entry according to measure of supplied heat energy by heating element of exhaust sensor
    DE102009000076A1 (en) 2009-01-08 2010-07-15 Robert Bosch Gmbh Method for determining dosage for reagent material drop entry in exhaust duct of internal combustion engine, involves operating exhaust gas sensor arranged in exhaust gas area with exhaust gas sensor-diagnostic temperature-set point
    DE102009001064A1 (en) 2009-02-23 2010-08-26 Robert Bosch Gmbh Method for determining measure for water drop entry into exhaust gas channel of internal combustion engine, involves comparing rise of sensor signal with threshold value, and providing measure for water drop entry after exceeding value
    DE102009028953A1 (en) 2009-08-27 2011-03-03 Robert Bosch Gmbh Method for determining measurement for occurrence of reagent central drop in exhaust area of internal-combustion engine, involves arranging particle sensor, which has reagent central drop

    Families Citing this family (34)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    DE19729696C2 (en) * 1997-07-11 2002-02-21 Bosch Gmbh Robert Method and device for monitoring the function of a gas probe
    US6304813B1 (en) * 1999-03-29 2001-10-16 Toyota Jidosha Kabushiki Kaisha Oxygen concentration detector and method of using same
    US6848439B2 (en) * 2001-11-08 2005-02-01 Hitachi Unisia Automotive, Ltd. Air-fuel ratio control apparatus, air-fuel ratio detecting apparatus and methods thereof for engine
    JP4110874B2 (en) * 2002-08-09 2008-07-02 株式会社デンソー Heating control device for gas sensor of internal combustion engine
    DE10260720A1 (en) * 2002-12-23 2004-07-15 Robert Bosch Gmbh Method for operating a gas sensor and device for carrying out the method
    JP2005207924A (en) * 2004-01-23 2005-08-04 Toyota Motor Corp Controller for exhaust gas sensor
    US7084378B2 (en) * 2004-02-26 2006-08-01 Mack Trucks, Inc. Mass-flow sensor heating element protection method and apparatus
    JP2007162486A (en) * 2005-12-09 2007-06-28 Denso Corp Control device for diesel engine
    JP4710615B2 (en) * 2006-01-10 2011-06-29 株式会社デンソー Heater control device for gas sensor
    JP2007198158A (en) * 2006-01-24 2007-08-09 Mazda Motor Corp Air fuel ratio control device for hydrogen engine
    KR101368302B1 (en) * 2006-03-31 2014-02-26 로나티 에스.피.에이. Circular knitting machine for hosiery or the like
    JP4325641B2 (en) 2006-05-24 2009-09-02 トヨタ自動車株式会社 Air-fuel ratio sensor control device
    DE102007031767A1 (en) 2007-07-27 2009-01-29 Audi Ag Exhaust gas sensor for detecting concentration of exhaust gas component of internal combustion engine, has ceramic sensor element as part of structure, with which concentration of exhaust component is detected
    EP2042714B1 (en) * 2007-09-25 2011-09-07 GM Global Technology Operations LLC Method for determining the dew point in an exhaust line and apparatus for determinig the dew point in an exhaust line
    DE102008013515A1 (en) 2008-03-07 2009-09-10 Volkswagen Ag Method for operating a lambda probe during the warm-up phase
    US8584445B2 (en) * 2009-02-04 2013-11-19 GM Global Technology Operations LLC Method and system for controlling an electrically heated particulate filter
    JP4992935B2 (en) 2009-05-21 2012-08-08 株式会社デンソー Exhaust gas sensor activation control device
    US8950177B2 (en) * 2009-06-17 2015-02-10 GM Global Technology Operations LLC Detecting particulate matter load density within a particulate filter
    US8443590B2 (en) * 2009-07-02 2013-05-21 GM Global Technology Operations LLC Reduced volume electrically heated particulate filter
    US8479496B2 (en) * 2009-07-02 2013-07-09 GM Global Technology Operations LLC Selective catalytic reduction system using electrically heated catalyst
    US8475574B2 (en) * 2009-08-05 2013-07-02 GM Global Technology Operations LLC Electric heater and control system and method for electrically heated particulate filters
    US8511069B2 (en) * 2009-08-12 2013-08-20 GM Global Technology Operations LLC Systems and methods for layered regeneration of a particulate matter filter
    DE102009054127B4 (en) * 2009-11-20 2021-11-25 Bayerische Motoren Werke Aktiengesellschaft Method for activating the heating of a lambda probe in an exhaust system with a catalytic converter that can be heated by the exhaust gas
    DE102009055041B4 (en) 2009-12-21 2021-12-09 Robert Bosch Gmbh Method for quickly achieving operational readiness of a heatable exhaust gas probe
    ITBO20120111A1 (en) * 2012-03-06 2013-09-07 Magneti Marelli Spa METHOD OF CONTROL OF AN AUTOMATIC MANUAL TRANSMISSION PROVIDED WITH A PARKING BLOCK DEVICE
    JP5737262B2 (en) * 2012-10-16 2015-06-17 トヨタ自動車株式会社 Control device for internal combustion engine
    DE102013226175A1 (en) 2013-12-17 2015-07-02 Robert Bosch Gmbh Method and device for operating exhaust gas sensors
    KR101619609B1 (en) 2014-09-05 2016-05-18 현대자동차주식회사 Air Flow Sensor chip-heating control device of diesel hybrid electric vehicle
    DE102016205060A1 (en) * 2016-03-24 2017-04-27 Continental Automotive Gmbh Method for operating a sensor for detecting oxidizable gases
    DE102017211024B4 (en) * 2017-06-29 2019-06-27 Robert Bosch Gmbh Method and device for activating a diagnosis of a particulate filter of an internal combustion engine
    US10975746B1 (en) * 2019-12-12 2021-04-13 GM Global Technology Operations LLC Varying closed loop gain control to constrain ramp rate of oxygen sensors in exhaust systems
    JP7415903B2 (en) * 2020-12-08 2024-01-17 トヨタ自動車株式会社 Internal combustion engine control device
    DE102021208577A1 (en) * 2021-08-06 2023-02-09 Robert Bosch Gesellschaft mit beschränkter Haftung Method for operating an exhaust gas sensor in an exhaust system of an internal combustion engine of a motor vehicle
    CN114967785A (en) * 2021-08-13 2022-08-30 长城汽车股份有限公司 Method and device for controlling heating of oxygen sensor, electronic equipment and storage medium

    Family Cites Families (20)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    DE2726458A1 (en) * 1977-06-11 1979-01-04 Bosch Gmbh Robert ELECTRICALLY POWERED RAPID HEATING DEVICE
    JPS55122143A (en) * 1979-03-15 1980-09-19 Nippon Soken Inc Gas detector
    JPS57203940A (en) * 1981-06-11 1982-12-14 Nissan Motor Co Ltd Gas sensor
    JPS60235048A (en) * 1984-05-07 1985-11-21 Toyota Motor Corp Method for controlling supply of current to resistance heat generation type electric heater of oxygen sensor
    JPS60235047A (en) * 1984-05-07 1985-11-21 Toyota Motor Corp Method for controlling temperature of oxygen sensor with heater for internal-combustion engine
    JPS60235050A (en) * 1984-05-07 1985-11-21 Toyota Motor Corp Method for controlling current supplied to electric heater of oxygen sensor
    US4715343A (en) * 1985-09-17 1987-12-29 Toyota Jidosha Kabushiki Kaisha Method and apparatus for controlling heater for heating air-fuel ratio sensor
    JPS62129754A (en) * 1985-11-29 1987-06-12 Honda Motor Co Ltd Control of oxygen concentration detector
    US4753204A (en) * 1986-09-30 1988-06-28 Mitsubishi Denki Kabushiki Kaisha Air-fuel ratio control system for internal combustion engines
    JPH01147138A (en) * 1987-12-01 1989-06-08 Mitsubishi Electric Corp Heater controller for air-fuel ratio sensor
    JPH07122627B2 (en) * 1987-12-16 1995-12-25 日本電装株式会社 Heater controller for oxygen concentration sensor
    JPH0738844Y2 (en) * 1988-10-07 1995-09-06 トヨタ自動車株式会社 Heater controller for oxygen sensor
    DE3840148A1 (en) * 1988-11-29 1990-05-31 Bosch Gmbh Robert METHOD AND DEVICE FOR DETECTING AN ERROR STATE OF A LAMB PROBE
    US4993392A (en) * 1989-04-24 1991-02-19 Toyota Jidosha Kabushiki Kaisha Apparatus for controlling heater for heating oxygen sensor
    DE3941995A1 (en) * 1989-12-20 1991-06-27 Bosch Gmbh Robert METHOD AND DEVICE FOR MONITORING THE OPERATIONAL OPERATION OF A PROBE HEATING DEVICE
    DE9006431U1 (en) * 1990-06-07 1990-08-30 Ortmann, Helmut, 8900 Augsburg Furniture glide foot
    JPH04148856A (en) * 1990-10-12 1992-05-21 Toyota Motor Corp Heater controlling device for oxygen-concentration detecting sensor
    DE4106541A1 (en) * 1991-03-01 1992-09-03 Bosch Gmbh Robert METHOD FOR TEMPERATURE CONTROL AND REGULATION OF EXHAUST GAS SENSORS
    DE9109219U1 (en) * 1991-07-26 1992-01-09 Wu, Chia Long, Kuei Ren Hsiang, Tainan Chain with chain links
    DE4132008C2 (en) * 1991-09-26 2000-04-06 Bosch Gmbh Robert Method and device for checking the functionality of an oxygen probe heater

    Cited By (4)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    DE102008040593A1 (en) 2008-03-03 2009-09-10 Robert Bosch Gmbh Method for determining measure of water entry into exhaust duct of internal combustion engine, involves determining measure of water entry according to measure of supplied heat energy by heating element of exhaust sensor
    DE102009000076A1 (en) 2009-01-08 2010-07-15 Robert Bosch Gmbh Method for determining dosage for reagent material drop entry in exhaust duct of internal combustion engine, involves operating exhaust gas sensor arranged in exhaust gas area with exhaust gas sensor-diagnostic temperature-set point
    DE102009001064A1 (en) 2009-02-23 2010-08-26 Robert Bosch Gmbh Method for determining measure for water drop entry into exhaust gas channel of internal combustion engine, involves comparing rise of sensor signal with threshold value, and providing measure for water drop entry after exceeding value
    DE102009028953A1 (en) 2009-08-27 2011-03-03 Robert Bosch Gmbh Method for determining measurement for occurrence of reagent central drop in exhaust area of internal-combustion engine, involves arranging particle sensor, which has reagent central drop

    Also Published As

    Publication number Publication date
    JP3464221B2 (en) 2003-11-05
    KR100261930B1 (en) 2000-08-01
    JPH07504754A (en) 1995-05-25
    DE4300530C2 (en) 2001-02-08
    WO1994016371A1 (en) 1994-07-21
    DE4300530A1 (en) 1994-07-14
    KR950700566A (en) 1995-01-16
    DE59309465D1 (en) 1999-04-22
    EP0635148A1 (en) 1995-01-25
    US5616835A (en) 1997-04-01

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