Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
  • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
  • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
  • G01N27/041—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D35/00—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for
  • F02D35/02—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions
  • F02D35/021—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions using an ionic current sensor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/14—Introducing closed-loop corrections
  • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
  • F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
  • F02D41/1466—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being a soot concentration or content
  • F02D41/1467—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being a soot concentration or content with determination means using an estimation
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
  • F02P17/00—Testing of ignition installations, e.g. in combination with adjusting; Testing of ignition timing in compression-ignition engines
  • F02P17/12—Testing characteristics of the spark, ignition voltage or current
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
  • F02P17/00—Testing of ignition installations, e.g. in combination with adjusting; Testing of ignition timing in compression-ignition engines
  • F02P17/12—Testing characteristics of the spark, ignition voltage or current
  • F02P2017/125—Measuring ionisation of combustion gas, e.g. by using ignition circuits

Definitions

• the present invention relates to a method of measuring the particle content, in particular the soot particle content, in the exhaust gases of an internal combustion engine by means of a sensor arranged in contact with the exhaust gases.
• soot When soot is formed in the exhaust gases, the combustion of the fuel injected into the combustion chamber becomes incomplete, which means that substances that have an effect on the environment are formed in the exhaust gases.
• o various measures can be taken. For example, the moment of fuel injection can be regulated and/or the moment of ignition of the air/fuel mixture in the combustion chamber can be regulated. It is also possible to regulate the ratio of air to fuel in the air/fuel mixture.
• the problem is detecting when soot formation in the exhaust gases is taking place and how much soot is being formed.
• a method and an arrangement for measuring the soot particle content in the exhaust gases of an internal combustion engine are described in DE-A1-33 04 548.
• An insulator in the form of a ceramic plate is located in the exhaust pipe of the internal combustion engine.
• Two electrodes are arranged on the insulator at a distance from one another so that a gap is formed between the 0 electrodes.
• soot adheres to the ceramic plate between the insulators.
• the soot then acts as an electric conductor between the electrodes.
• the quantity of soot on the ceramic plate is proportional to the resistance between the electrodes. The more soot that adheres to the ceramic plate, the smaller the resistance becomes. The 5 resistance can then be measured and an idea of the soot particle content can thus be obtained.
• One object of the present invention is to provide a method of the type 5 indicated in the introduction which gives a picture of the particle content in the exhaust gases in the combustion chamber of an internal combustion engine.
• a further object of the present invention is to provide a method of o continuously measuring during operation of the engine the particle content in the exhaust gases in the combustion chamber of an internal combustion engine and, against the background of measurement values obtained, regulating the internal combustion engine so that a lower particle content in the exhaust gases is obtained.
• the senor detects in at least one combustion chamber of the internal combustion engine a quantity, the size of which is dependent on the particle content in the exhaust gases, and that the level of a measurement signal output from the sensor, which signal is dependent on the detected quantity, is determined and compared with a desired value level of a signal which corresponds to a desired particle content in the exhaust gases.
• Such a method of measuring the particle content in the exhaust gases provides a true picture of how complete the combustion of the fuel in the combustion chamber is.
• a sensor located in the combustion chamber such as the spark plug of a GDI engine and the heater plug of a diesel engine, simple and economical measuring equipment is obtained for measuring the particle content in the exhaust gases in the combustion chamber in conventional GDI and diesel engines.
• Fig. 1 relates to a coordinate system which shows the ionic current as a function of the crankshaft angle in the case of low soot particle content in the exhaust gases in the combustion chamber,
• Fig. 2 relates to a coordinate system which shows the ionic current as a function of the crankshaft angle in the case of a soot particle content in the exhaust gases in the combustion chamber which is greater than the soot particle content represented by the function in Fig. 1,
• Fig. 3 relates to a diagrammatically represented sensor and measuring unit in the case of a GDI engine,
• Fig. 4 relates to a diagrammatically represented sensor and measuring unit in the case of a diesel engine, and
• Fig. 5 shows a diagrammatic view of a measuring unit connected to a spark plug.
• Figs 1 and 2 show a graph 1 which represents the ionic current Ij that is formed in the combustion chamber of a piston engine in connection with the combustion stroke.
• the graph 1 is drawn in a coordinate system where the X axis represents the crankshaft angle ⁇ and the Y axis represents the ionic current Ij.
• Fig. 3 shows an embodiment in which a measuring unit 2 is connected to the spark plug 3 of a GDI engine 4.
• the spark plug 3 therefore constitutes a sensor for providing signals to the measuring unit 2.
• Fig. 4 shows another embodiment, in which a measuring unit 2' is connected to a heater plug 5 of a diesel engine 6 of the prechamber type.
• the heater plug 5 in this case constitutes a sensor which provides signals to the measuring unit 2'.
• the graph for the ionic current signals shown in Fig. 1 consists of three different stages, namely the ignition stage S, the flame ionization stage F and the post-ionization stage P.
• the ignition stage S the charging action of the current in the ignition coil produces an interference which gives rise to a small current peak.
• a spark from the spark plug 3 then produces a strong pulse with a negative sign (broken line in Fig. 1). This negative pulse is filtered out.
• a large pulse then follows, which arises when the current to the spark plug 3 is broken.
• the flame ionization stage F a burning core of fuel/air mixture in or at the spark plug gap produces a pulse peak.
• the post-ionization stage P the combustion pressure in the combustion chamber 7 rises to its highest value and the flame front has then reached the walls of the combustion chamber 7.
• a number of graphs for different operating conditions and different air/fuel mixtures of an "ideal" internal combustion engine can be stored, in respect of which operating conditions and air/fuel mixtures a desired soot particle content in the exhaust gases is obtained.
• the level of these graphs is calculated and desired values are obtained for o different operating conditions and air/fuel mixtures.
• the level of the graph 1 means the position of the entire graph 1 above the X axis in the coordinate system. If the ionic current Ij increases for each crankshaft angle ⁇ during the combustion stroke, the entire graph 1 is shifted 5 upwards in the coordinate system, that is to say the level increases.
• the level of the graph 1, which represents the ionic current Ij that is detected by the sensor 3, 5 arranged in the combustion chamber 7, can be calculated in different ways in the measuring unit 2, 2' connected to the sensor. For o example, one or more points of the sampled measurement signal, where the first derivative changes the sign from positive to negative, can be detected. Consequently, a value of the ionic current Ij at the peaks of each stage S, F and P is then obtained. These values provide a measure of the level of the graph 1. Another way of obtaining the level of the graph 1 is to integrate the 5 ionic current Ij as a function of the time during the combustion stroke or a part thereof. The integral consequently provides the area under the graph 1, which is a measure of the level of the graph 1.
• Fig. 5 shows a measuring unit 2 connected to a conventional spark plug 3.
• the measuring unit 2" is connected between the positive and negative (earth potential) electrodes 8 and 9 respectively of the spark plug 3.
• Fig. 5 also shows diagrammatically how an ignition coil 13 is connected to the spark plug 3.
• soot particles When soot particles are formed during the combustion stroke, these adhere to the insulator 11. The more soot particles that are formed, the thicker the soot deposit on the insulator 11 becomes.
• the soot particles conduct current, as a result of which a leakage current I L arises between the positive electrode 8 and the housing 10 which is connected to earth.
• the size of the leakage current I is a measure of the soot particle content in the exhaust gases.
• the leakage current affects the measurement of the ionic current Ij in such a manner that when soot particles adhere to the insulator 11, the leakage current I I increases and thus the level of the ionic current signal also increases during measurement of the ionic current Ij.
• the leakage current I L can itself be measured by a predetermined current being induced between the electrode 8 and the housing 10. The current that will then be transmitted between the electrode 8 and the housing 10 constitutes the leakage current I L .
• Fig. 2 shows this leakage current I as a straight line at the end of and after the post-ionization stage P and also before and during the ignition stage S.
• the leakage current I L is suitably measured at given defined crankshaft angles ⁇ or points in time, that is to say in given measurement windows, in which measurement windows the predetermined current is induced between the electrode 8 and the housing 10.
• the predetermined current that is induced between the electrode 8 and the housing 10 can be induced continuously during the cycle of the whole engine, that is to say during all strokes, for which a suitable measurement window can be defined by detecting the leakage current IT, when the first derivative of the latter is zero for a continuous time interval.
• the impedance Z between the electrode 8 and the housing 10 is measured as the soot particles that adhere to the insulator 11 conduct current. As the soot particles that adhere to the insulator 11 conduct current, the impedance Z between the electrode 8 and the housing 10 will decrease when soot particles adhere to the insulator 11. When the impedance Z between the electrode 8 and the housing 10 is measured, the resistance, inductance and capacitance between the electrode 8 and the housing 10 will be taken into consideration at one and the same time of measurement. Instead of measuring the impedance Z, the resistance, inductance and capacitance can be measured individually.
• a suitable measurement window for measuring the soot particle content in the combustion chamber 7, 7 may be during charging of the ignition coil 13 during the ignition stage F. This can be advantageous when the soot particle content is to be measured in a number of combustion chambers 7, 7 of the internal combustion engine 4, 6 because it then becomes simple to coordinate the measurements between the various sensors 3, 5.
• the moment of ignition, the moment of fuel injection and/or the air/fuel mixture can be regulated so that the soot particle content in the exhaust gases decreases.
• the soot particle content in the exhaust gases has decreased, the soot deposited on the insulator 11 will be burnt off during the combustion stroke.
• Measurement of the soot particle content in a diesel engine 6 takes place in a similar manner to that described above.
• the heater plug 5 has an insulator 5 (not shown), to which soot particles can adhere.
• the diesel engine 6 is also regulated by the measuring unit 2' being connected to a control unit 12' which adjusts the moment of fuel injection and the volume of fuel injected.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Combustion & Propulsion (AREA)
• Life Sciences & Earth Sciences (AREA)
• Electrochemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Health & Medical Sciences (AREA)
• Physics & Mathematics (AREA)
• Analytical Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
• Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
• Combined Controls Of Internal Combustion Engines (AREA)
• Testing Of Engines (AREA)
• Ignition Installations For Internal Combustion Engines (AREA)
• Spark Plugs (AREA)

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Publications (1)

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• 1997
  • 1997-12-01 SE SE9704460A patent/SE513432C2/sv not_active IP Right Cessation
• 1998
  • 1998-11-30 AU AU15806/99A patent/AU1580699A/en not_active Abandoned
  • 1998-11-30 US US09/555,481 patent/US6466022B1/en not_active Expired - Fee Related
  • 1998-11-30 JP JP2000539251A patent/JP2002508470A/ja active Pending
  • 1998-11-30 DE DE69821390T patent/DE69821390T2/de not_active Expired - Fee Related
  • 1998-11-30 EP EP98960134A patent/EP1036268B1/en not_active Expired - Lifetime
  • 1998-11-30 WO PCT/SE1998/002180 patent/WO1999031369A1/en active IP Right Grant

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