EP0877159B1 - Process for checking the operability of the heater of a lambda sensor in the exhaust pipe of an internal combustion engine - Google Patents
Process for checking the operability of the heater of a lambda sensor in the exhaust pipe of an internal combustion engine Download PDFInfo
- Publication number
- EP0877159B1 EP0877159B1 EP98106013A EP98106013A EP0877159B1 EP 0877159 B1 EP0877159 B1 EP 0877159B1 EP 98106013 A EP98106013 A EP 98106013A EP 98106013 A EP98106013 A EP 98106013A EP 0877159 B1 EP0877159 B1 EP 0877159B1
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- Prior art keywords
- heater
- heating
- resistor
- current
- internal combustion
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- 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
-
- 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
- F02D41/1495—Detection of abnormalities in the air/fuel ratio feedback system
Definitions
- the invention relates to a method for checking the functionality the electrical heating of a lambda sensor in the exhaust pipe Internal combustion engine according to the preamble of patent claim 1.
- the oxygen content of the exhaust gas is measured with a lambda probe determined and the value determined in this way fed to a control device, which serves to set a predetermined air / fuel ratio.
- the lambda probe is only operational above a minimum operating temperature.
- the regulation of the air / fuel mixture by means of Lambda probe only possible when the lambda probe has reached its operating temperature has reached. Only then can one be low
- Optimal air / fuel mixture can be regulated.
- the operating temperature of the Lambda probe is heated by a electric heating accelerates. In terms of low pollutant emissions it is therefore necessary for the operability of the lambda probe heater to check. It is known that aging of the electrical resistance of such a heater changes with time.
- the temperature-dependent electrical resistance of the lambda probe heating is therefore measured in the known method according to DE 41 32 008 A1 when a predetermined operating temperature is reached.
- a device is used, for example, which is also shown schematically in FIG. 3.
- the lambda probe heater is connected in the form of a heating resistor R L between the drain electrode of a field effect transistor T1 (or the collector of a bipolar transistor) and the positive pole of a battery.
- the source electrode of the field effect transistor T1 (or the emitter of a bipolar transistor) is connected via a measuring resistor R measurement to the negative pole of the battery or to ground.
- a control output of the microprocessor is connected to the control electrode of the field effect transistor T1 (or to the base of a bipolar transistor).
- the microprocessor ⁇ P has other inputs and outputs for controlling different functions.
- the source electrode of transistor T1 (or the emitter of a bipolar transistor) is connected via a resistor R2 or via an operational amplifier to the input of an A / D converter, the output of which leads to an input of the microprocessor ⁇ P.
- the heating resistor R L is energized by means of the battery voltage U + when the heating resistor R L is connected to the battery B via a relay R and the microprocessor .mu.P connects transistor T1 to ground by actuating the control electrode.
- the resistor R L can also be connected directly to the battery B, saving the relay R.
- the heating resistor of the lambda sensor heater at ambient temperatures is very low compared to the operating temperature, flows when switched on the lambda sensor heater a very high current.
- the measuring resistor dimensioned such that a sufficient at operating temperature accurate measurement is possible during the warm-up phase of the lambda probe a high power is converted into heat in the measuring resistor.
- Control devices e.g. B. engine control units
- this problem either with a large measuring resistor or by reduction the performance is solved by clocking the heating current.
- large measuring resistance requires a large printed circuit board area and is relatively expensive. Reducing performance through Clocking in turn undesirably extends the time period to one Lambda control is possible.
- the electrical resistance of the heater is measured when the heating current is switched off.
- the heating is with a Measuring current applied, which is smaller than the heating current. This resistance measurement is preferably carried out if the Lamda probe has reached its operating temperature.
- the heating is different to the prior art according to DE 41 32 008 A1, in which the Heating for the application of (heating) current is switched to ground, for the application of (measuring or heating) current against positive voltage connected.
- the power loss in the resistance measurement avoided because the heating resistor is not during the Heating current is measured, but in the switched off state.
- a resistor R1 by means of which a measuring current I M is predetermined, is connected in parallel to the transistor T1.
- the heating is switched off in a first step, ie the transistor T1 is blocked, so that heating current I H can no longer flow.
- the relay R is closed, only a small measuring current I M flows through the resistor R1, which is also applied to the probe heater or its heating resistor R L.
- the microprocessor ⁇ P calculates the value of the heating resistor R L from the voltage drop U measured over the heating resistor R L , the known value of the resistor R1 and the battery voltage U +.
- the measurement of the heating resistance R L can also be carried out at any other probe temperature or also in the cold state, ie in the unheated state. Since there is a known relationship between the probe temperature or the temperature of the heating resistor and the ohmic value of the heating resistor, on the one hand the measured heating resistance can be used to draw conclusions about the current probe temperature, but on the other hand it can compare the measured value with an expected value of the heating resistor if the probe temperature is known become. If the difference between these values exceeds a certain threshold value, it is concluded that there is an error. To monitor the correct functionality of the heating, a predetermined course of the ohmic values of the heating resistor over a certain period of time can also be compared with an actually determined course.
- one connection of the lambda probe heater or the heating resistor R L is connected firmly to ground, while the other connection can be switched against the battery voltage U +.
- a diode D1 connected to ground between the resistor R2 and the A / D converter limits the voltage at the A / D converter input when the heating is switched on. If the resistor R2 is selected to have a very high resistance and at the same time the A / D converter input is sufficiently protected internally, the diode D1 can also be omitted.
- the main relay R usually present in motor vehicles ensures that the measuring current is switched off when the vehicle is parked.
- FIG. 2 shows an alternative with respect to FIG. 1 in that the resistor R1 extra with a measuring voltage of 5 V instead of the battery voltage U + is applied.
- the voltage of 5 V is usually the supply voltage a control device of a control device.
- the 5 V voltage is the reference for the A / D converter, which makes the Voltage measurement of the battery voltage U + can be omitted.
- 1 to 3 are usually in internal combustion engine control units integrated, which also regulates an optimal Make air / fuel mixture.
- the exemplary embodiments according to the invention make it possible to dispense with low-resistance measuring resistors (R measurement ) with high power.
- R measurement low-resistance measuring resistors
- a 1% SMD standard resistor of the 1206 design can be used. This reduces costs and saves space on the circuit board, especially when considering the fact that several lambda probes often have to be switched per control unit.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Measurement Of Resistance Or Impedance (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
- Measuring Oxygen Concentration In Cells (AREA)
Description
Die Erfindung bezieht sich auf ein Verfahren zur Überprüfung der Funktionsfähigkeit der elektrischen Heizung einer Lambda-Sonde im Abgasrohr einer Brennkraftmaschine nach dem Oberbegriff des Patentanspruchs 1.The invention relates to a method for checking the functionality the electrical heating of a lambda sensor in the exhaust pipe Internal combustion engine according to the preamble of patent claim 1.
Ein derartiges Verfahren ist beispielsweise aus der DE 41 32 008 A1 bekannt. Dieses bekannte Verfahren wird auch anhand der schematischen Darstellung nach Fig. 3 der Zeichnung im folgenden erläutert.Such a method is known for example from DE 41 32 008 A1. This known method is also based on the schematic 3 of the drawing explained below.
Grundsätzlich wird mit einer Lambda-Sonde der Sauerstoffgehalt des Abgases bestimmt und der so ermittelte Wert einer Regeleinrichtung zugeführt, die dazu dient, ein vorgegebenes Luft-/Kraftstoffverhältnis einzustellen. Die Lambda-Sonde ist nur oberhalb einer minimalen Betriebstemperatur funktionsbereit. Somit ist die Regelung des Luft-/Kraftstoffgemisches mittels der Lambda-Sonde erst dann möglich, wenn die Lambda-Sonde ihre Betriebstemperatur erreicht hat. Nur dann kann ein im Hinblick auf eine niedrige Schadstoffemission optimales Luft-/Kraftstoffgemisch eingeregelt werden. Um die Emissionswerte gering zu halten, soll die Betriebstemperatur der Lambda-Sonde möglichst schnell nach dem Start der Brennkraftmaschine erreicht werden. Daher wird ein Aufheizen der Lambda-Sonde durch eine elektrische Heizung beschleunigt. Im Sinne einer geringen Schadstoffemission ist es daher erforderlich, die Funktionsfähigkeit der Lambda-Sonden-Heizung zu überprüfen. Es ist bekannt, daß sich durch Alterung der elektrische Widerstand einer derartigen Heizung mit der Zeit ändert.Basically, the oxygen content of the exhaust gas is measured with a lambda probe determined and the value determined in this way fed to a control device, which serves to set a predetermined air / fuel ratio. The The lambda probe is only operational above a minimum operating temperature. Thus, the regulation of the air / fuel mixture by means of Lambda probe only possible when the lambda probe has reached its operating temperature has reached. Only then can one be low Optimal air / fuel mixture can be regulated. In order to keep the emission values low, the operating temperature of the Lambda probe as quickly as possible after starting the internal combustion engine can be achieved. Therefore, the lambda probe is heated by a electric heating accelerates. In terms of low pollutant emissions it is therefore necessary for the operability of the lambda probe heater to check. It is known that aging of the electrical resistance of such a heater changes with time.
Zur Überprüfung der Lambda-Sonden-Heizung wird daher bei dem bekannten Verfahren nach der DE 41 32 008 A1 bei Erreichen einer vorgegebenen Betriebstemperatur der temperaturabhängige elektrische Widerstand der Lambda-Sonden-Heizung gemessen. Hierzu wird beispielsweise eine Vorrichtung verwendet, die auch in Fig. 3 schematisch dargestellt ist. Die Lambda-Sonden-Heizung ist in Form eines Heizwiderstandes RL zwischen die Drain-Elektrode eines Feldeffekttransistors T1 (oder dem Kollektor eines Bipolartransistors) und den Pluspol einer Batterie geschaltet. Die Source-Elektrode des Feldeffekttransistors T1 (oder der Emitter eines Bipolartransistors) ist über einen Meßwiderstand Rmeß mit dem Minuspol der Batterie bzw. mit Masse verbunden. Ein Steuerausgang des Mikroprozessors (µP) ist mit der Steuerelektrode des Feldeffekttransistors T1 (oder mit der Basis eines Bipolartransistors) verbunden. Der Mikroprozessor µP weist noch weitere Ein- und Ausgänge zur Steuerung unterschiedlicher Funktionen auf. Darüber hinaus ist die Source-Elektrode des Transistors T1 (oder der Emitter eines Bipolartransistors) über einen Widerstand R2 oder über einen Operationsverstärker mit dem Eingang eines A/D-Wandlers verbunden, dessen Ausgang an einen Eingang des Mikroprozessors µP führt. Die Bestromung des Heizwiderstandes RL mittels der Batteriespannung U+ wird vorgenommen, wenn der Heizwiderstand RL über ein Relais R mit der Batterie B verbunden ist und der Mikroprozessor µP durch Ansteuerung der Steuerelektrode den Transistor T1 gegen Masse durchschaltet. Alternativ kann der Widerstand RL unter Einsparung des Relais R auch direkt mit der Batterie B verbunden sein.To check the lambda probe heating, the temperature-dependent electrical resistance of the lambda probe heating is therefore measured in the known method according to DE 41 32 008 A1 when a predetermined operating temperature is reached. For this purpose, a device is used, for example, which is also shown schematically in FIG. 3. The lambda probe heater is connected in the form of a heating resistor R L between the drain electrode of a field effect transistor T1 (or the collector of a bipolar transistor) and the positive pole of a battery. The source electrode of the field effect transistor T1 (or the emitter of a bipolar transistor) is connected via a measuring resistor R measurement to the negative pole of the battery or to ground. A control output of the microprocessor (µP) is connected to the control electrode of the field effect transistor T1 (or to the base of a bipolar transistor). The microprocessor µP has other inputs and outputs for controlling different functions. In addition, the source electrode of transistor T1 (or the emitter of a bipolar transistor) is connected via a resistor R2 or via an operational amplifier to the input of an A / D converter, the output of which leads to an input of the microprocessor μP. The heating resistor R L is energized by means of the battery voltage U + when the heating resistor R L is connected to the battery B via a relay R and the microprocessor .mu.P connects transistor T1 to ground by actuating the control electrode. Alternatively, the resistor R L can also be connected directly to the battery B, saving the relay R.
Bei dem aus der DE 41 32 008 A1 bekannten Verfahren werden bei eingeschalteter Heizung, d. h. bei durchgeschaltetem Transistor T1, die Batteriespannung U+ und die Meßspannung Umeß, die über den Meßwiderstand Rmeß abfällt, erfaßt. Im Zusammenhang mit dem bekannten Wert des Meßwiderstands Rmeß wird daraus über den Mikroprozessor µP der Heizwiderstand RL berechnet (vgl. auch Fig. 3).In the method known from DE 41 32 008 A1, when the heating is switched on, ie when the transistor T1 is switched on, the battery voltage U + and the measurement voltage U measurement , which drops across the measurement resistor R measurement, are detected . In connection with the known value of the measuring resistor R measurement , the heating resistor R L is calculated therefrom via the microprocessor μP (cf. also FIG. 3).
Da der Heizwiderstand der Lambdasonden-Heizung bei Umgebungstemperaturen im Vergleich zur Betriebstemperatur sehr gering ist, fließt beim Einschalten der Lambdasonden-Heizung ein sehr hoher Strom. Wird der Meßwiderstand derart dimensioniert, daß bei Betriebstemperatur eine hinreichend genaue Messung möglich ist, wird in der Aufwärmphase der Lambda-Sonde im Meßwiderstand eine hohe Leistung in Wärme umgesetzt. In bekannten Regeleinrichtungen, z. B. Motorsteuergeräten, wird dieses Problem entweder mit einem leistungsmäßig großen Meßwiderstand oder durch Reduzierung der Leistung mittels Takten des Heizstroms gelöst. Ein leistungsmäßig großer Meßwiderstand benötigt jedoch eine große Leiterplattenfläche und ist verhältnismäßig kostenintensiv. Die Reduzierung der Leistung durch Takten verlängert wiederum in unerwünschter Weise die Zeitdauer bis eine Lambdaregelung möglich ist.Because the heating resistor of the lambda sensor heater at ambient temperatures is very low compared to the operating temperature, flows when switched on the lambda sensor heater a very high current. Will the measuring resistor dimensioned such that a sufficient at operating temperature accurate measurement is possible during the warm-up phase of the lambda probe a high power is converted into heat in the measuring resistor. In known ones Control devices, e.g. B. engine control units, this problem either with a large measuring resistor or by reduction the performance is solved by clocking the heating current. A performance however, large measuring resistance requires a large printed circuit board area and is relatively expensive. Reducing performance through Clocking in turn undesirably extends the time period to one Lambda control is possible.
Es ist Aufgabe der Erfindung, ein Verfahren eingangs genannter Art derart zu verbessern, daß auf einen Hochleistungsmeßwiderstand verzichtet wird und dennoch die Zeitdauer bis zur ordnungsgemäßen Lambdaregelung nicht unnötig verlängert wird.It is an object of the invention to provide a method of the type mentioned at the outset to improve that a high-performance measuring resistor is dispensed with and still not the time until proper lambda control is extended unnecessarily.
Diese Aufgabe wird durch die kennzeichnenden Merkmale des Patentanspruchs 1 gelöst.This object is achieved by the characterizing features of the patent claim 1 solved.
Erfindungsgemäß wird der elektrische Widerstand der Heizung gemessen, wenn der Heizstrom ausgeschaltet ist. Dabei wird die Heizung mit einem Meßstrom beaufschlagt, der kleiner als der Heizstrom ist. Vorzugsweise wird diese Messung des Widerstands vorgenommen, wenn die Lamda-Sonde ihre Betriebstemperatur erreicht hat.According to the invention, the electrical resistance of the heater is measured when the heating current is switched off. The heating is with a Measuring current applied, which is smaller than the heating current. This resistance measurement is preferably carried out if the Lamda probe has reached its operating temperature.
In einer vorteilhaften Ausgestaltung der Erfindung wird die Heizung im Unterschied zum Stand der Technik nach der DE 41 32 008 A1, bei dem die Heizung zur Beaufschlagung mit (Heiz-) Strom gegen Masse geschaltet wird, zur Beaufschlagung mit (Meß- oder Heiz-) Strom gegen positive Spannung geschaltet. Hierdurch wird die Messung des Widerstandes der Heizung vereinfacht, da insbesondere der gesamte A/D-Wandler-Bereich ausgenützt werden kann.In an advantageous embodiment of the invention, the heating is different to the prior art according to DE 41 32 008 A1, in which the Heating for the application of (heating) current is switched to ground, for the application of (measuring or heating) current against positive voltage connected. This simplifies the measurement of the heating resistance, because in particular the entire A / D converter area is used can be.
Durch das erfindungsgemäße Verfahren wird die Verlustleistung bei der Widerstandsmessung vermieden, da der Heizwiderstand nicht während der Heizbestromung gemessen wird, sondern im abgeschalteten Zustand.Through the method according to the invention, the power loss in the resistance measurement avoided because the heating resistor is not during the Heating current is measured, but in the switched off state.
In der Zeichnung ist ein Ausführungsbeispiel der Erfindung dargestellt. Es zeigt
- Fig. 1
- eine Schaltung zur Durchführung des erfindungsgemäßen Verfahrens nach einer ersten Alternative und
- Fig. 2
- eine Schaltung zur Durchführung des erfindungsgemäßen Verfahrens nach einer zweiten Alternative.
- Fig. 1
- a circuit for performing the inventive method according to a first alternative and
- Fig. 2
- a circuit for performing the inventive method according to a second alternative.
In der Zeichnung sind gleiche Bauteile mit gleichen Bezugszeichen versehen. In Fig. 1 ist im Unterschied zum Stand der Technik (Fig. 3) ein Widerstand R1, durch den ein Meßstrom IM vorgegeben wird, parallel zum Transistor T1 geschaltet. Der Heizwiderstand RL (= zu messender elektrischer Widerstand der Heizung) ist einerseits an der Source-Elektrode des Transistors T1 (oder am Emitter eines Bipolartransistors) angeschlossen und andererseits fest gegen Masse geschaltet.In the drawing, the same components are provided with the same reference numerals. 1, in contrast to the prior art (FIG. 3), a resistor R1, by means of which a measuring current I M is predetermined, is connected in parallel to the transistor T1. The heating resistor R L (= electrical resistance of the heating to be measured) is connected on the one hand to the source electrode of the transistor T1 (or to the emitter of a bipolar transistor) and on the other hand is permanently connected to ground.
Ist vorzugsweise eine vorgegebene Betriebstemperatur der Lambdasonde erreicht, wird in einem ersten Schritt die Heizung ausgeschaltet, d. h. der Transistor T1 gesperrt, so daß kein Heizstrom IH mehr fließen kann. Bei geschlossenem Relais R fließt über den Widerstand R1 lediglich ein kleiner Meßstrom IM, mit dem auch die Sondenheizung bzw. deren Heizwiderstand RL beaufschlagt wird. Der Mikroprozessor µP berechnet den Wert des Heizwiderstandes RL aus dem Spannungsabfall Umeß über den Heizwiderstand RL, dem bekannten Wert des Widerstands R1 und der Batteriespannung U+.If a predetermined operating temperature of the lambda probe is preferably reached, the heating is switched off in a first step, ie the transistor T1 is blocked, so that heating current I H can no longer flow. When the relay R is closed, only a small measuring current I M flows through the resistor R1, which is also applied to the probe heater or its heating resistor R L. The microprocessor µP calculates the value of the heating resistor R L from the voltage drop U measured over the heating resistor R L , the known value of the resistor R1 and the battery voltage U +.
Ergänzend wird darauf hingewiesen, daß die Messung des Heizwiderstandes
RL auch bei jeder anderen Sondentemperatur bzw. auch im Kaltzustand,
d.h. im unbeheiztem Zustand, durchgeführt werden kann.
Da eine bekannte Beziehung zwischen der Sondentemperatur bzw. der
Temperatur des Heizwiderstandes und dem ohmschen Wert des Heizwiderstandes
besteht, kann einerseits von dem gemessenen Heizwiderstand auf
die momentan vorliegende Sondentemperatur geschlossen werden, andererseits
jedoch bei bekannter Sondentemperatur der gemessene mit einem
zu erwartenden Wert des Heizwiderstandes verglichen werden. Überschreitet
die Differenz dieser Werte einen bestimmten Schwellwert, wird auf das
Vorliegen eines Fehlers geschlossen.
Zur Überwachung der korrekten Funktionsfähigkeit der Heizung kann auch
ein vorgegebenerr Verlauf der ohmschen Werte des Heizwiderstandes über
einer bestimmten Zeitspanne mit einem tatsächlich ermittelten Verlauf verglichen
werden.In addition, it is pointed out that the measurement of the heating resistance R L can also be carried out at any other probe temperature or also in the cold state, ie in the unheated state.
Since there is a known relationship between the probe temperature or the temperature of the heating resistor and the ohmic value of the heating resistor, on the one hand the measured heating resistance can be used to draw conclusions about the current probe temperature, but on the other hand it can compare the measured value with an expected value of the heating resistor if the probe temperature is known become. If the difference between these values exceeds a certain threshold value, it is concluded that there is an error.
To monitor the correct functionality of the heating, a predetermined course of the ohmic values of the heating resistor over a certain period of time can also be compared with an actually determined course.
Damit die Meßspannung Umeß im gesamten Spannungsbereich des A/D-Wandlers liegt, ist ein Anschluß der Lambdasonden-Heizung bzw. des Heizwiderstands RL fest gegen Masse geschaltet, während der andere Anschluß gegen die Batteriespannung U+ schaltbar ist. Eine zwischen dem Widerstand R2 und dem A/D-Wandler gegen Masse geschaltete Diode D1 begrenzt die Spannung am A/D-Wandlereingang bei eingeschalteter Heizung. Wird der Widerstand R2 sehr hochohmig gewählt und ist gleichzeitig der A/D-Wandlereingang intern ausreichend geschützt, kann die Diode D1 auch entfallen. Durch das in Kraftfahrzeugen üblicherweise vorhandene Hauptrelais R ist sichergestellt, daß der Meßstrom bei abgestelltem Fahrzeug ausgeschaltet ist.So that the measuring voltage U meas lies in the entire voltage range of the A / D converter, one connection of the lambda probe heater or the heating resistor R L is connected firmly to ground, while the other connection can be switched against the battery voltage U +. A diode D1 connected to ground between the resistor R2 and the A / D converter limits the voltage at the A / D converter input when the heating is switched on. If the resistor R2 is selected to have a very high resistance and at the same time the A / D converter input is sufficiently protected internally, the diode D1 can also be omitted. The main relay R usually present in motor vehicles ensures that the measuring current is switched off when the vehicle is parked.
Fig. 2 stellt eine Alternative bezüglich Fig. 1 dar, indem der Widerstand R1 extra mit einer Meßspannung von 5 V anstatt mit der Batteriespannung U+ beaufschlagt wird. Üblicherweise ist die Spannung von 5 V die Versorgungsspannung eines Steuergeräts einer Regeleinrichtung. Gleichzeitig ist üblicherweise die 5 V-Spannung die Referenz für den A/D-Wandler, wodurch die Spannungsmessung der Batteriespannung U+ entfallen kann. FIG. 2 shows an alternative with respect to FIG. 1 in that the resistor R1 extra with a measuring voltage of 5 V instead of the battery voltage U + is applied. The voltage of 5 V is usually the supply voltage a control device of a control device. At the same time is common the 5 V voltage is the reference for the A / D converter, which makes the Voltage measurement of the battery voltage U + can be omitted.
Die Schaltungen nach den Fig. 1 bis 3 sind üblicherweise in Brennkraftmaschinensteuergeräten integriert, die auch die Regelung eines optimalen Luft-/ Kraftstoffgemisches vornehmen.1 to 3 are usually in internal combustion engine control units integrated, which also regulates an optimal Make air / fuel mixture.
Folgende Bauteilwerte der Schaltungen nach Fig. 1 und Fig. 2 sind besonders
vorteilhaft:
Durch die erfindungsgemäßen Ausführungsbeispiele kann im Gegensatz zu den im Einsatz befindlichen Schaltungen auf niederohmige Meßwiderstände (Rmeß) hoher Leistung verzichtet werden. Für den Widerstand R1 zur Bestimmung des Meßstroms IM kann beispielsweise ein 1%iger SMD-Standardwiderstand der Bauform 1206 verwendet werden. Dies reduziert die Kosten und spart Platz auf der Leiterplatte, insbesondere bei Berücksichtigung der Tatsache, daß häufig mehrere Lambda-Sonden pro Steuergerät geschaltet werden müssen.In contrast to the circuits in use, the exemplary embodiments according to the invention make it possible to dispense with low-resistance measuring resistors (R measurement ) with high power. For the resistor R1 for determining the measuring current I M , for example, a 1% SMD standard resistor of the 1206 design can be used. This reduces costs and saves space on the circuit board, especially when considering the fact that several lambda probes often have to be switched per control unit.
Claims (2)
- A method for testing the functional capability of the electrical heater of a Lambda-Sonde in the exhaust pipe of an internal combustion engine, in which the electrical resistance of the heater is measured, characterised in that the electrical resistance (RL) of the heater is measured when the heater current (IH) is switched off and that the heater is subjected to a test current (IM=U+/R1) for the measurement of its electrical resistance (RL), which is smaller than the heater current (IH).
- A method according to claim 1 characterised in that the electrical resistance (RL) of the heater is connected to the positive voltage (U+) for the application of heating or measurement current (IM, IH).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19719390A DE19719390A1 (en) | 1997-05-07 | 1997-05-07 | Method for checking the functionality of the electrical heating of a lambda probe in the exhaust pipe of an internal combustion engine |
| DE19719390 | 1997-05-07 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0877159A2 EP0877159A2 (en) | 1998-11-11 |
| EP0877159A3 EP0877159A3 (en) | 1999-12-29 |
| EP0877159B1 true EP0877159B1 (en) | 2003-06-25 |
Family
ID=7828955
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP98106013A Expired - Lifetime EP0877159B1 (en) | 1997-05-07 | 1998-04-02 | Process for checking the operability of the heater of a lambda sensor in the exhaust pipe of an internal combustion engine |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US5929328A (en) |
| EP (1) | EP0877159B1 (en) |
| JP (1) | JPH1183790A (en) |
| DE (2) | DE19719390A1 (en) |
| ES (1) | ES2202676T3 (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19956823C2 (en) * | 1999-11-25 | 2002-11-28 | Siemens Ag | Control circuit and control method for a gas sensor |
| US7481915B2 (en) * | 2001-02-08 | 2009-01-27 | Ford Global Technologies, Llc | Exhaust gas temperature measurement utilizing an exhaust gas sensor |
| US6586711B2 (en) * | 2001-07-27 | 2003-07-01 | General Motors Corporation | Current control method for an oxygen sensor heater |
| DE102006014681A1 (en) * | 2006-03-28 | 2007-10-04 | Robert Bosch Gmbh | Gas sensor for internal combustion engine, has pump supply line and heating pipeline that are electrically connected with each other and commonly ground, where Nernst voltage is measured between measuring line and reference pump supply line |
| CN102854393B (en) * | 2012-09-08 | 2014-12-24 | 无锡隆盛科技股份有限公司 | Heating detecting circuit and heating detecting method for nitrogen and oxygen sensor |
| DE102015222554A1 (en) | 2015-11-16 | 2017-05-18 | Inficon Gmbh | Leak detection with oxygen |
| DE102016202854A1 (en) * | 2016-02-24 | 2017-08-24 | Volkswagen Aktiengesellschaft | Method and device for operating a lambda probe in an exhaust passage of an internal combustion engine |
| US10563605B2 (en) * | 2018-03-13 | 2020-02-18 | Ford Global Technologies, Llc | Systems and methods for reducing vehicle emissions |
| US11092101B2 (en) | 2018-08-22 | 2021-08-17 | Rosemount Aerospace Inc. | Heater in-circuit capacitive measurement |
| US11078859B2 (en) * | 2019-10-11 | 2021-08-03 | Fca Us Llc | Oxygen sensor out of specification heater rationality monitor using cold start cycle |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07122627B2 (en) * | 1987-12-16 | 1995-12-25 | 日本電装株式会社 | Heater controller for oxygen concentration sensor |
| 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 |
| DE4132008C2 (en) | 1991-09-26 | 2000-04-06 | Bosch Gmbh Robert | Method and device for checking the functionality of an oxygen probe heater |
| US5245979A (en) * | 1992-10-28 | 1993-09-21 | Ford Motor Company | Oxygen sensor system with a dynamic heater malfunction detector |
| US5454259A (en) * | 1993-08-02 | 1995-10-03 | Toyota Jidosha Kabushiki Kaisha | Failure detecting apparatus in temperature controller of air-fuel ratio sensor |
| US5392643A (en) * | 1993-11-22 | 1995-02-28 | Chrysler Corporation | Oxygen heater sensor diagnostic routine |
| DE4344961B4 (en) * | 1993-12-30 | 2004-05-06 | Robert Bosch Gmbh | Evaluation device for the signal of an oxygen probe |
| JP3711582B2 (en) * | 1995-03-31 | 2005-11-02 | 株式会社デンソー | Oxygen concentration detector |
-
1997
- 1997-05-07 DE DE19719390A patent/DE19719390A1/en not_active Withdrawn
-
1998
- 1998-04-02 ES ES98106013T patent/ES2202676T3/en not_active Expired - Lifetime
- 1998-04-02 DE DE59808786T patent/DE59808786D1/en not_active Expired - Fee Related
- 1998-04-02 EP EP98106013A patent/EP0877159B1/en not_active Expired - Lifetime
- 1998-04-28 JP JP10119263A patent/JPH1183790A/en not_active Ceased
- 1998-05-07 US US09/073,915 patent/US5929328A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| ES2202676T3 (en) | 2004-04-01 |
| EP0877159A2 (en) | 1998-11-11 |
| US5929328A (en) | 1999-07-27 |
| DE59808786D1 (en) | 2003-07-31 |
| JPH1183790A (en) | 1999-03-26 |
| DE19719390A1 (en) | 1998-11-12 |
| EP0877159A3 (en) | 1999-12-29 |
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