WO2015107911A1 - Exhaust gas purification apparatus for an internal combustion engine - Google Patents

Exhaust gas purification apparatus for an internal combustion engine Download PDF

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Publication number
WO2015107911A1
WO2015107911A1 PCT/JP2015/000234 JP2015000234W WO2015107911A1 WO 2015107911 A1 WO2015107911 A1 WO 2015107911A1 JP 2015000234 W JP2015000234 W JP 2015000234W WO 2015107911 A1 WO2015107911 A1 WO 2015107911A1
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WO
WIPO (PCT)
Prior art keywords
amount
filter
valve
time
exhaust
Prior art date
Application number
PCT/JP2015/000234
Other languages
English (en)
French (fr)
Inventor
Hiromasa Hashimoto
Takayuki Otsuka
Takashi Tsunooka
Noriyasu Kobashi
Original Assignee
Toyota Jidosha Kabushiki Kaisha
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Application filed by Toyota Jidosha Kabushiki Kaisha filed Critical Toyota Jidosha Kabushiki Kaisha
Publication of WO2015107911A1 publication Critical patent/WO2015107911A1/en

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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
    • F02D41/0002—Controlling intake air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D13/0203—Variable control of intake and exhaust valves
    • F02D13/0215—Variable control of intake and exhaust valves changing the valve timing only
    • F02D13/0219—Variable control of intake and exhaust valves changing the valve timing only by shifting the phase, i.e. the opening periods of the valves are constant
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D13/0261—Controlling the valve overlap
    • 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
    • F02D41/021—Introducing corrections for particular conditions exterior to the engine
    • F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
    • F02D41/027—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus
    • F02D41/029—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus the exhaust gas treating apparatus being a particulate filter
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

Definitions

  • the present invention relates to an exhaust gas purification apparatus for an internal combustion engine.
  • a filter for trapping particulate matter (hereinafter also referred to as "PM") in exhaust gas may be arranged in an exhaust passage of an internal combustion engine.
  • PM particulate matter
  • the resistance to the exhaust gas in the filter becomes large.
  • the pressure of the exhaust gas will go up.
  • the PM thus deposited is oxidized in a state where the amount of the PM deposited on the filter (hereinafter, also referred to as the amount of PM deposition)
  • the amount of PM deposition there is a fear of causing an overheating of the filter. For this reason, before the amount of PM deposition in the filter increases to an excessive extent, it will be necessary to remove by oxidation the PM deposited on the filter.
  • the processing to remove the PM from the filter is referred to as the regeneration of the filter.
  • the temperature of the filter it is necessary that the temperature of the filter have become equal to or higher than a predetermined temperature, and that oxygen exist in the interior of the filter.
  • the present invention has been made in view of the problems as referred to above, and has for its object to increase an opportunity for carrying out regeneration of a filter.
  • an exhaust gas purification apparatus for an internal combustion engine which includes: a filter that is arranged in an exhaust passage of the internal combustion engine for trapping particulate matter contained in an exhaust gas; a valve timing changing device that changes at least one of a timing at which an intake valve of said internal combustion engine is opened and a timing at which an exhaust valve of said internal combustion engine is closed; a control device that adjusts at least one of a length of a valve overlap period of time and a timing of valve overlap, by operating said valve timing changing device; and a deposition amount acquisition device that measures or estimates an amount of particulate matter deposited on said filter; wherein said control device operates said valve timing changing device in such a manner that in cases where a pressure in an intake passage of said internal combustion engine is higher than a pressure in the exhaust passage of said internal combustion engine, an amount of air passing from said intake passage to said exhaust passage through a cylinder in said valve overlap period of time becomes larger when the amount of the particulate matter deposited
  • the predetermined amount referred to herein is an amount of PM deposition at which it is desirable to carry out the regeneration of the filter, and is an amount of PM deposition smaller than an amount of PM deposition at which there takes place a rise in the pressure of the exhaust gas, an overheating of the filter, or the like.
  • the predetermined amount may also be set as an amount of PM deposition which has a margin with respect to the amount of PM deposition at which there takes place a rise in the pressure of the exhaust gas, an overheating of the filter, or the like.
  • the predetermined amount can also be set as an amount of PM deposition at which the regeneration of the filter is carried out when other conditions than the amount of PM deposition are satisfied.
  • the predetermined amount can also be set as an amount of PM deposition at which the regeneration of the filter is required. That is, it can be said that in cases where the amount of particulate matter (PM) deposited on the filter is equal to or larger than the predetermined amount, there is a requirement for carrying out the regeneration processing of the filter.
  • PM particulate matter
  • the control device can cause a valve overlap to take place, can change the length of the valve overlap period of time, or can change the timing of valve overlap.
  • the valve overlap period of time is a period of time in which both the intake valve and the exhaust valve are open. This period of time corresponds to a period of time from when the intake valve begins to open until when the exhaust valve is completely closed.
  • the timing of valve overlap may also be set as a point in time at which the intake valve begins to open and a point in time at which the exhaust valve is completely closed.
  • the control device can shift only the timing of valve overlap while leaving the valve overlap period of time as it is, by shifting the opening timing of the intake valve and the closing timing of the exhaust valve by the same amount.
  • valve overlap occurs at the time the pressure in the intake passage is higher than the pressure in the exhaust passage, air in the intake passage can flow into the exhaust passage, while passing through a cylinder.
  • the pressure in the intake passage can become higher than the pressure in the exhaust passage in a predetermined operating region.
  • oxygen is contained in the air which flows into the exhaust passage at this time. Accordingly, in cases where the pressure in the intake passage is higher than the pressure in the exhaust passage, and in cases where valve overlap has occurred, oxygen can be supplied to the filter. With this oxygen, it is possible to promote the oxidation of PM (particulate matter).
  • a larger amount of oxygen can be supplied to the filter by operating the valve timing changing device in such a manner that the amount of air passing from the intake passage to the exhaust passage through the cylinder becomes large (i.e., is increased).
  • the amount of air passing from the intake passage to the exhaust passage through the cylinder during the valve overlap period of time is changed by changing the length of the valve overlap period of time or the timing of valve overlap. For this reason, by adjusting the length of the valve overlap period of time or the timing of valve overlap, it is possible to make large the amount of air passing through the cylinder. According to this, the amount of oxygen to be supplied to the filter can be caused to increase, so that the regeneration of the filter can be promoted. In this manner, the opportunity for the regeneration of the filter to be carried out can be increased.
  • the amount of air passing from the intake passage to the exhaust passage through the cylinder may become zero. That is, the amount of air passing from the intake passage to the exhaust passage through the cylinder being increased may include causing a change from a state where there is no air passing from the intake passage to the exhaust passage through the cylinder into a state where there is air passing from the intake passage to the exhaust passage through the cylinder. Stated in another way, it can includes causing a change from a state where valve overlap has not occurred into a state where valve overlap has occurred.
  • Said control device can make larger the amount of air passing from said intake passage to said exhaust passage through the cylinder, by making said valve overlap period of time longer.
  • the control device makes the valve overlap period of time longer when the amount of PM deposition is equal to or larger than the predetermined amount, than when it is less than the predetermined amount.
  • the valve overlap period of time is made longer, the period of time in which air passes from the intake passage to the exhaust passage becomes longer, so the amount of air passing to the exhaust passage can be increased.
  • the amount of oxygen supplied to the filter is increased, thus making it possible to promote the oxidation of PM.
  • Said control device can operate said valve timing changing device so that valve overlap can occur in a period of time in which pressure becomes lower in order of the pressure in the intake passage of the internal combustion engine, the pressure in the cylinder of the internal combustion engine, and the pressure in the exhaust passage of the internal combustion engine.
  • Said control device can make larger the amount of air passing through into said exhaust passage, by bringing a center of said valve overlap period of time closer to a point in time at which the flow speed of air passing from said intake passage to said exhaust passage through the cylinder becomes a maximum.
  • the center of the valve overlap period of time may also be set as the mid-point in time between the point in time at which the intake valve begins to open and the point in time at which the exhaust valve is completely closed.
  • the center of the valve overlap period of time corresponds, in terms of crank angle degree, to a crank angle which is obtained by dividing, by 2, a value of the sum of a crank angle at the time the intake valve begins to open and a crank angle at the time the exhaust valve is completely closed.
  • the intake valve and the exhaust valve are open to the same extent, so that it becomes easy for air to pass through from the intake passage to the exhaust passage.
  • the degree of opening of the exhaust valve is relatively large, but the degree of opening of the intake valve becomes relatively small. For this reason, it becomes difficult for air to pass through the intake valve, and hence, the amount of air passing through the cylinder becomes relatively small.
  • the degree of opening of the intake valve is relatively large, but the degree of opening of the exhaust valve becomes relatively small. For this reason, it becomes hard for air to pass through the exhaust valve, and hence, the amount of air passing through the cylinder becomes relatively small.
  • the pressure in the intake passage, the pressure in the cylinder and the pressure in the exhaust passage change according to the crank angle, etc. Moreover, the flow speed of air passing from the intake passage to the exhaust passage through the cylinder changes according to these pressures.
  • the timing of valve overlap is caused to change, the flow speed of air passing through the cylinder in the center of the valve overlap is changed.
  • control device may increase or make large the amount of air passing through the cylinder, by matching the center of said valve overlap period of time with the point in time at which the flow speed of air passing from said intake passage to said exhaust passage through the cylinder becomes a maximum.
  • control device can also increase or make large the amount of air passing through the cylinder, by bringing the center of said valve overlap period of time within a predetermined range including the point in time at which the flow speed of air passing from said intake passage to said exhaust passage through the cylinder becomes a maximum.
  • Said control device can make larger the amount of air passing through into said exhaust passage, by bringing a point in time, at which an opening area of the intake valve and an opening area of the exhaust valve during said valve overlap period of time become the same with each other, closer to the point in time at which the flow speed of air passing from said intake passage to said exhaust passage through the cylinder becomes a maximum.
  • the opening area of the intake valve becomes larger in a gradual manner, and the opening area of the exhaust valve becomes smaller in a gradual manner. That is, during the valve overlap period of time, it becomes easier for air to pass through the intake valve, whereas it becomes more difficult for air to pass through the exhaust valve.
  • the opening area of the intake valve becomes relatively small, so that the resistance of air at the time of passing through the intake valve is relatively large. For this reason, the amount of air passing through from the intake passage to the exhaust passage is limited by the intake valve.
  • the opening area of the exhaust valve becomes relatively small, so that the resistance of air at the time of passing through the exhaust valve is relatively large. For this reason, the amount of air passing through from the intake passage to the exhaust passage is limited by the exhaust valve. That is, the amount of air passing through from the intake passage to the exhaust passage is limited by the valve of which the opening area is smaller.
  • Said control device can make larger the amount of air passing from said intake passage to said exhaust passage through the cylinder, by making the center of said valve overlap period of time closer to the top dead center of exhaust stroke.
  • Said control device can operate said valve timing changing device in such a manner that the amount of air passing from said intake passage to said exhaust passage through the cylinder becomes larger in accordance with the increasing amount of the particulate matter deposited on said filter.
  • the charging efficiency can be increased, or the amount of internal EGR gas can be suppressed from decreasing more than needed.
  • the amount of air passing through the cylinder can be suppressed to a necessary minimum, by decreasing the amount of air passing through the cylinder in accordance with the decreasing amount of PM deposition in the filter.
  • Said control device can operate said valve timing changing device in such a manner that the amount of air passing from said intake passage to said exhaust passage through the cylinder becomes larger, when the temperature of said filter is equal to or higher than a predetermined temperature at which the particulate matter deposited on said filter is oxidized.
  • the temperature of the filter needs to be high to a sufficient extent. That is, the regeneration of the filter is carried out at the time when the temperature of the filter is equal to or higher than the predetermined temperature at which the filter temperature is sufficiently high. Accordingly, when the temperature of the filter is equal to or higher than the predetermined temperature, it is possible to promote the oxidation of the PM deposited on the filter, by making the amount of air passing through the cylinder large. On the other hand, when the temperature of the filter is less than the predetermined temperature, it is possible to promote suppression of the deterioration in fuel economy as well as a decrease in the amount of emission of NOx, by making the amount of air passing through the cylinder relatively small.
  • a turbocharger that serves to rotate a turbine by making use of the exhaust gas of said internal combustion engine, wherein in cases where said valve timing changing device is operated so as to increase the amount of air passing from said intake passage to said exhaust passage through the cylinder, and in cases where there is a request for raising the supercharging pressure, when the amount of the particulate matter deposited on said filter is less than a second predetermined amount which is larger than said predetermined amount, said control device can operate said valve timing changing device so as to make larger the amount of air passing from said intake passage to said exhaust passage through the cylinder until a point in time at which said request for raising the supercharging pressure ceases to exist, and when the amount of the particulate matter deposited on said filter is equal to or larger than said second predetermined amount, said control device can operate said valve timing changing device so as to make larger the amount of air passing from said intake passage to said exhaust passage through the cylinder at least until a point in time at which the amount of the particulate matter deposited on said filter becomes less than said second predetermined
  • the time when there is a request for raising the supercharging pressure may also be, for example, a time when it is necessary to increase the torque of the internal combustion engine, or a time of acceleration.
  • the number of revolutions per minute of the turbine of the turbocharger can be increased, thus making it possible to cause the supercharging pressure to go up quickly. Accordingly, in cases where there is a request for raising the supercharging pressure, the supercharging pressure can be caused to go up quickly, by adjusting the valve overlap period of time so as to increase the amount of air passing through into the exhaust passage.
  • a period of time and a point in time of the valve overlap, which are set at this time, may be the same as or different from the values set at the time of removing the PM from the filter.
  • the amount of air passing through into the exhaust passage is continued to increase even after the supercharging pressure has gone up, the amount of the air remaining in the cylinder decreases, so that the amount of the air involved in combustion therein decreases. As a result of this, it will be difficult to maintain the supercharging pressure at a high level.
  • by decreasing the amount of air passing through the cylinder after the supercharging pressure has become high, i.e., after the request for raising the supercharging pressure ceases to exist the supercharging pressure can be maintained high.
  • the control device gives priority to the regeneration of the filter, in cases where there is a request for raising the supercharging pressure, and in cases where the amount of the PM deposited on the filter is equal to or larger than the second predetermined amount.
  • priority is given to the rise of the supercharging pressure, in cases where there is a request for raising the supercharging pressure, and in cases where the amount of the PM deposited on the filter is less than the second predetermined amount.
  • the second predetermined amount is a value which is larger than the predetermined amount, and is an amount of PM at which it is considered better to give priority to the regeneration of the filter over the rise of the supercharging pressure.
  • the second predetermined amount may also be, for example, an amount of PM at which if priority is given to the rise of the supercharging pressure over the regeneration of the filter, the amount of the PM deposited on the filter exceeds an allowable value. For that reason, in cases where the amount of the PM deposited on the filter is equal to or larger than the second predetermined amount, priority is given to the regeneration of the filter over the rise of the supercharging pressure. As a result of this, the PM can be quickly removed from the filter. On the other hand, in cases where the amount of the PM deposited on the filter is less than the second predetermined amount, priority is given to the rise of the supercharging pressure over the regeneration of the filter.
  • the opportunity for the regeneration of the filter to be carried out can be increased.
  • Fig. 1 is a view showing the schematic construction of an internal combustion engine according to an embodiment of the present invention.
  • Fig. 2 is a view showing a predetermined low rotation and high load region.
  • Fig. 3 is a flow chart showing a control flow for valve timing according to a first embodiment of the present invention.
  • Fig. 4 is a flow chart showing a control flow for valve timing according to a second embodiment of the present invention.
  • Fig. 5 is a flow chart showing a control flow for valve timing according to a third embodiment of the present invention.
  • Fig. 6 is a view showing the relation between crank angle and pressure in a cylinder (cylinder internal pressure) in the vicinity of the top dead center of exhaust stroke in the predetermined low rotation and high load region.
  • Fig. 7 is a view showing the changes over time of opening areas of an intake valve and an exhaust valve.
  • Fig. 8 is a flow chart showing a control flow for valve timing according to a sixth embodiment of the present invention.
  • Fig. 1 is a view showing the schematic construction of an internal combustion engine 1 according to an embodiment of the present invention.
  • the internal combustion engine 1 is a gasoline engine of spark ignition type.
  • the internal combustion engine 1 is installed on a vehicle, for example.
  • the internal combustion engine 1 may have a plurality of cylinders.
  • An intake pipe 42 and an exhaust pipe 72 are connected to a cylinder head 10 of the internal combustion engine 1.
  • An intake port 41 which leads to a cylinder 2 from the intake pipe 42, and an exhaust port 71, which leads to the cylinder 2 from the exhaust pipe 72, are formed in the cylinder head 10.
  • the intake port 41 is provided at its one end at the side of the cylinder 2 with an intake valve 5.
  • the opening and closing operation of the intake valve 5 is carried out by an intake side cam 6.
  • the exhaust port 71 is provided at its one end at the side of the cylinder 2 with an exhaust valve 9.
  • the opening and closing operation of the exhaust valve 9 is carried out by an exhaust side cam 11.
  • the intake port 41 and the intake pipe 42 are included in an intake passage 4.
  • the exhaust port 71 and the exhaust pipe 72 are included in an exhaust passage 7.
  • the intake side cam 6 is mounted on an intake side cam shaft 22, and in addition, an intake side pulley 24 is arranged at an end of the intake side cam shaft 22. Between the intake side cam shaft 22 and the intake side pulley 24, there is arranged a variable rotational phase mechanism (hereinafter referred to as an "intake side VVT") 23 which is able to change the relative rotational phase between the intake side cam shaft 22 and the intake side pulley 24.
  • intake side VVT variable rotational phase mechanism
  • exhaust side cam 11 is mounted on an exhaust side cam shaft 25, and further, an exhaust side pulley 27 is arranged at an end of the exhaust side cam shaft 25.
  • exhaust side VVT variable rotational phase mechanism
  • the intake side VVT 23 can change the opening and closing timing of the intake valve 5 by changing the relation between the rotation angle of the crankshaft 13, and the rotation angle of the intake side cam shaft 22.
  • the exhaust side VVT 26 can change the opening and closing timing of the exhaust valve 9 by changing the relation between the rotation angle of the crankshaft 13, and the rotation angle of the exhaust side cam shaft 25.
  • at least one of the intake side VVT 23 and the exhaust side VVT 26 needs only to be provided.
  • the opening and closing timing of the intake valve 5 or the exhaust valve 9 may be changed by means of other mechanisms.
  • the intake side VVT 23 or the exhaust side VVT 26 corresponds to a valve timing changing device in the present invention.
  • a piston 15 connected to the crankshaft 13 of the internal combustion engine 1 through a connecting rod 14 reciprocates within the cylinder 2.
  • turbocharger 50 In the middle of the intake pipe 42, there is arranged a compressor 51 of a turbocharger 50 that is driven to operate with the use of the energy of exhaust gas as a driving source.
  • the turbocharger is used in this embodiment, but instead of this, a mechanical supercharger driven by the crankshaft 13 may be used.
  • a throttle valve 16 that serves to adjust the flow rate of intake air flowing through the intake pipe 42.
  • an intake air pressure sensor 96 that serves to output a signal corresponding to the pressure in the intake pipe 42. A supercharging pressure is detected by the intake air pressure sensor 96.
  • the turbine 52 of the turbocharger 50 is arranged in the middle of the exhaust pipe 72.
  • a three-way catalyst 31 is arranged in the exhaust pipe 72 at a location downstream of the turbine 52.
  • the three-way catalyst 31 needs only to be a catalyst having an oxidation function, and may be an oxidation catalyst or an NOx catalyst.
  • a filter 32 which serves to trap particulate matter (PM) in the exhaust gas, is arranged in the exhaust pipe 72 at a location downstream of the three-way catalyst 31.
  • a three-way catalyst may be supported by the filter 32, separately from the three-way catalyst 31 arranged at the upstream side of the filter 32.
  • a first temperature sensor 93 for measuring the temperature of the exhaust gas is arranged in the exhaust pipe 72 at a location downstream of the three-way catalyst 31 and upstream of the filter 32. Further, a second temperature sensor 94 for measuring the temperature of the exhaust gas is arranged in the exhaust pipe 72 at a location downstream of the filter 32.
  • the temperature of the three-way catalyst 31 or the temperature of the filter 32 can be estimated based on an output value of the first temperature sensor 93.
  • the temperature of the filter 32 can be estimated based on an output value of the second temperature sensor 94.
  • the temperature of the three-way catalyst 31 and the temperature of the filter 32 can also be estimated based on an operating state of the internal combustion engine 1.
  • an in-passage fuel injection valve 81 for injecting fuel in a direction toward the intake port 41.
  • an in-cylinder fuel injection valve 82 for injecting fuel into the cylinder 2.
  • a spark plug 83 for generating an electric spark in the cylinder 2.
  • an ECU 90 which is an electronic control unit for controlling the internal combustion engine 1.
  • This ECU 90 is provided with a CPU, a ROM and a RAM which store a variety of kinds of programs and maps, and so on, and controls the internal combustion engine 1 in accordance with the operating conditions of the internal combustion engine 1 and/ or driver's requirements.
  • an accelerator opening sensor 91 and a crank position sensor 92 in addition to the above-mentioned various kinds of sensors are electrically connected to the ECU 90.
  • the ECU 90 receives a signal corresponding to an accelerator opening from the accelerator opening sensor 91, and calculates an engine load to be required by the internal combustion engine 1, etc., according to this signal. Also, the ECU 90 receives a signal corresponding to the rotation angle of an output shaft of the internal combustion engine 1 from the crank position sensor 92, and calculates the number of engine revolutions per unit time of the internal combustion engine 1.
  • the intake side VVT 23, the exhaust side VVT 26, the in-passage fuel injection valve 81, the in-cylinder fuel injection valve 82, and the spark plug 83 are connected to the ECU 90 through electrical wiring, so that these parts or elements are controlled by the ECU 90.
  • the ECU 90 corresponds to a control device in the present invention.
  • the ECU 90 estimates the amount of PM deposition in the filter 32.
  • the amount of PM deposition may be estimated based on the number of engine revolutions per unit time and the engine load in the past, or may be estimated based on a difference between the pressure of the exhaust gas at the upstream side of the filter 32 and at the downstream side of the three-way catalyst 31 and the pressure of the exhaust gas at the downstream side of the filter 32 (hereinafter, also referred to as a filter differential pressure) and the flow rate of the exhaust gas.
  • the amount of the PM to be discharged from the internal combustion engine 1 is in a correlation with the number of engine revolutions per unit time and the engine load, and hence, the amount of the PM to be discharged from the internal combustion engine 1 can be obtained based on the number of engine revolutions per unit time and the engine load.
  • the amount of PM deposition can be obtained by integrating this amount of the PM to be discharged from the internal combustion engine 1.
  • the larger the amount of PM deposition in the filter 32 the larger becomes the filter differential pressure. This filter differential pressure is also changed by the flow rate of the exhaust gas.
  • the amount of PM deposition can be obtained from the filter differential pressure and the flow rate of the exhaust gas.
  • the amount of PM deposition increases according to the operation period of time of the internal combustion engine 1 or the distance of travel of the vehicle, so that the amount of PM deposition can also be estimated based on these values in a simple and easy manner.
  • the ECU 90 which estimates the amount of PM deposition in the filter 32, corresponds to a deposition amount acquisition device in the present invention.
  • the ECU 90 supplies oxygen to the filter 32 for regeneration of the filter 32, when the amount of PM deposition in the filter 32 becomes equal to or larger than a predetermined amount.
  • the predetermined amount is an amount of PM deposition at which it is desirable to carry out the regeneration of the filter 32.
  • the predetermined amount is an amount of PM deposition which is smaller than an amount of PM deposition with which the resistance of the exhaust gas due to the PM deposited on the filter 32 poses a problem, and which has a margin with respect to the amount of PM deposition with which the resistance of the exhaust gas due to the PM deposited on the filter 32 poses a problem.
  • the predetermined amount can also be set as an amount of PM deposition at which the regeneration of the filter 32 is carried out when other conditions than the amount of PM deposition are satisfied. Moreover, the predetermined amount can also be set as an amount of PM deposition at which the regeneration of the filter 32 is required.
  • the predetermined amount is too small, the regeneration of the filter 32 is frequently carried out, so there is concern about deterioration of fuel economy, etc.
  • the predetermined amount is too large, there is concern about a reduction in the output power of the internal combustion engine 1 due to a rise in the pressure of the exhaust gas, etc. In view of these, the predetermined value has been obtained in advance through experiments, simulations or the like.
  • air flowing from the intake passage 4 into the exhaust passage 7 while passing through the cylinder 2 is simply referred to as air passing through the cylinder 2.
  • the air passing through the cylinder 2 arrives at the filter 32. Oxygen, being contained in the air, is supplied to the filter 32.
  • Fig. 2 is a view showing the predetermined low rotation and high load region.
  • An axis of abscissa represents the number of engine revolutions per unit time, and an axis of ordinate represents the engine load (this may also be the accelerator opening degree or the amount of fuel injection).
  • the predetermined low rotation and high load region is an operating region in which the pressure in the intake passage 4 becomes higher than the pressure in the exhaust passage 7, and is an operating region in which air passes through the cylinder 2 by causing valve overlap.
  • the internal combustion engine 1 is operated in the predetermined low rotation and high load region at the time of acceleration or hill climbing.
  • the ECU 90 operates at least one of the intake side VVT 23 and the exhaust side VVT 26 so as to cause valve overlap. Moreover, the ECU 90 operates at least one of the intake side VVT 23 and the exhaust side VVT 26 in such a manner that the amount of air flowing from the intake passage 4 to the exhaust passage 7 while passing through the cylinder 2 (i.e., the amount of air passing through the cylinder 2) becomes larger in the case where the amount of PM deposition in the filter 32 is equal to or larger than the predetermined amount, than in the case where it is less than the predetermined amount.
  • the amount of air passing through the cylinder 2 being increased or made large may include making a change from a state where the air passing through the cylinder 2 does not exist to a state where the air passing through the cylinder 2 exists.
  • Fig. 3 is a flow chart showing a control flow or routine for valve timing according to this embodiment of the present invention.
  • the routine in this flow chart is carried out by means of the ECU 90 at each predetermined time interval.
  • step S101 the ECU 90 estimates the amount of PM deposition in the filter 32.
  • the amount of PM deposition may be estimated based on the number of engine revolutions per unit time and the engine load in the past, or may be estimated based on the above-mentioned filter differential pressure. Moreover, the amount of PM deposition can also be estimated in a simple and easy manner based on the operation period of time of the internal combustion engine 1 or the distance of travel of the vehicle.
  • step S102 the ECU 90 determines whether the amount of PM deposition estimated in step S101 is equal to or more than the predetermined amount.
  • the predetermined amount is, for example, an amount of PM deposition at which the regeneration of the filter 32 is required.
  • the predetermined amount has been obtained in advance through experiments, simulations or the like, as mentioned above. In cases where an affirmative determination is made in step S102, the routine advances to step S103, whereas in cases where a negative determination is made, the routine advances to step S105.
  • step S103 the ECU 90 determines whether the internal combustion engine 1 is operated in the predetermined low rotation and high load region. In this step, it is determined whether the internal combustion engine 1 is operated in an operating region where the pressure in the intake passage 4 becomes higher than the pressure in the exhaust passage 7.
  • the ECU 90 determines, based on the number of engine revolutions per unit time and the engine load by the use of Fig. 2, whether the internal combustion engine 1 is operated in the predetermined low rotation and high load region.
  • the routine advances to step S104, whereas in cases where a negative determination is made, the routine advances to step S105.
  • step S104 the ECU 90 sets the control mode of valve timing to a regeneration mode.
  • the regeneration mode is a control mode which serves to adjust the length of the valve overlap period of time to a length suitable for the regeneration of the filter 32.
  • the length of the valve overlap period of time and the timing of the valve overlap are set so that the amount of air passing through the cylinder 2 becomes larger than that in a normal mode set in step S105, which will be described later.
  • the valve overlap period of time in the regeneration mode is made longer than the valve overlap period of time set in step S105 to be described later.
  • the amount of oxygen supplied to the filter 32 is increased, thus making it possible to promote the regeneration of the filter 32.
  • valve overlap period of time when the valve overlap period of time is made too long, there is a fear that the intake valve 5 or the exhaust valve 9 may interfere with the piston 15. For that reason, when the valve overlap period of time is made long, the valve timing is changed within a range in which the intake valve 5 and the exhaust valve 9 do not interfere with the piston 15.
  • step S105 the ECU 90 sets the control mode of valve timing to the normal mode.
  • the normal mode is a control mode which serves to adjust the length of the valve overlap period of time to a length suitable for the improvement in fuel economy or the reduction of toxic or harmful substances in the exhaust gas. For this reason, in the normal mode, the valve timing is adjusted so that the charging efficiency of the internal combustion engine 1 is enhanced, or the amount of internal EGR gas is increased.
  • valve overlap period of time set in the normal mode may also be set as a length in which unburnt fuel does not flow into the exhaust passage 7.
  • the normal mode may also be set as a control mode in the case where there is no need to carry out the regenerating the filter 32.
  • the ECU 90 decides the valve timing of at least one of the intake valve 5 and the exhaust valve 9 based on, for example, the number of engine revolutions per unit time and the engine load.
  • the valve overlap period of time set in the normal mode is shorter than the valve overlap period of time set in the regeneration mode. Note that the timing of the valve overlap may be changed between the regeneration mode and the normal mode.
  • the timing of the valve overlap can be changed by adjusting at least one of a point in time at which the intake valve 5 begins to open or a point in time at which the exhaust valve 9 is completely closed.
  • the amount of air passing through the cylinder 2 be made larger at the time of the regeneration mode than at the time of the normal mode.
  • the amount of air Msca passing through the cylinder 2 can be calculated based on the pressure in the intake passage 4.
  • the amount of air passing through the cylinder 2 is in a correlation with the pressure in the intake passage 4, wherein the relation between the amount of air passing through the cylinder 2 and the pressure in the intake passage 4 can be represented by a linear expression.
  • a relational expression which is approximately held between the pressure in the intake passage 4 and the amount of air passing through the cylinder 2, and which is a linear expression in which the amount of air passing through the cylinder 2 becomes zero when the pressure in the intake passage 4 is a threshold pressure.
  • the amount of air Msca passing through the cylinder 2 can be calculated by the following linear expression (for example, refer to Japanese patent laid-open publication No. 2013-104330).
  • Msca E x (Pm - Pc) ...
  • Expression 1 where E is a coefficient; Pm is the pressure in the intake passage 4; and Pc is the threshold pressure.
  • the coefficient E can be obtained in advance through experiments, simulations, or the like.
  • the pressure Pm in the intake passage 4 is measured by the intake air pressure sensor 96.
  • the threshold pressure Pc is an estimated value of the pressure in the exhaust passage 7 which is calculated based on the information with respect to the operating state of the internal combustion engine 1.
  • the relation between the operating state of the internal combustion engine 1 and the threshold pressure Pc can be obtained in advance by experiments, simulations, or the like.
  • the amount of air passing through the cylinder 2 can also be calculated by means of other well-known technologies.
  • the amount of air passing through the cylinder 2 has also been able to be obtained by experiments, simulations or the like, and made into a map, while making it in association with the number of engine revolutions per unit time and the engine load.
  • valve overlap in the normal mode is that the charging efficiency of the internal combustion engine 1 is increased or the amount of internal EGR gas is made large.
  • valve timing set in the regeneration mode is for the purpose of making large the amount of air passing through the cylinder 2. For this reason, though valve overlap has occurred in both the regeneration mode and the normal mode, the valve timing in the regeneration mode is different from that in the normal mode.
  • the valve overlap periods of time and the timing of the valve overlap at the time of the regeneration mode and the normal mode can be obtained in advance by experiments, simulations, or the like.
  • the amount of PM deposition in the filter 32 is less than the predetermined amount, the amount of air passing through the cylinder 2 becomes small, so that deterioration of fuel economy can be suppressed, or an increase in the toxic or harmful substances in the exhaust gas can be suppressed.
  • the charging efficiency can be enhanced or the amount of internal EGR gas can be increased, by setting the control mode to the normal mode, even if the amount of PM deposition in the filter 32 is equal to or larger than the predetermined amount. For that reason, in this embodiment, the regeneration mode is carried out only when the temperature of the filter 32 is equal to or higher than the predetermined temperature.
  • Fig. 4 is a flow chart showing a control flow or routine for valve timing according to this embodiment of the present invention.
  • the routine in this flow chart is carried out by means of the ECU 90 at each predetermined time interval. Note that for those steps in which the same processing as in the aforementioned flow chart is carried out, the same symbols are attached and an explanation thereof is omitted.
  • step S201 the ECU 90 estimates the temperature of the filter 32. Because the temperature of the filter 32 changes according to the number of engine revolutions per unit time and the engine load in the past, it is possible to estimate the temperature of the filter 32 based on the number of engine revolutions per unit time and the engine load in the past. Such a relation may have beforehand been obtained through experiments, etc.
  • the temperature of the filter 32 can also be obtained based on the output value of the first temperature sensor 93 or the output value of the second temperature sensor 94.
  • a temperature sensor may be directly mounted on the filter 32, so that the temperature of the filter 32 can be measured by means of this temperature sensor.
  • step S202 the ECU 90 determines whether the temperature of the filter 32 estimated in step S201 is equal to or higher than the predetermined temperature.
  • the predetermined temperature is a temperature at which the PM is oxidized. That is, in step S202, it is determined whether the temperature of the filter 32 is a temperature at which the regeneration of the filter 32 can be carried out.
  • the predetermined temperature may be set in consideration of this temperature drop.
  • the predetermined temperature may be set to be higher by an amount of temperature by which the temperature of the filter 32 drops at the time of air passing therethrough than a lower limit value of the temperature at which the PM is oxidized.
  • the ECU 90 sets the control mode of valve timing to the regeneration mode. For this reason, it is possible to suppress the valve overlap period of time from becoming long at such a temperature that the regeneration of the filter 32 is not carried out. As a result of this, deterioration of fuel economy can be suppressed, or an increase in the toxic or harmful substances in the exhaust gas can be suppressed.
  • the temperature of the filter 32 may be caused to go up to the predetermined temperature or above.
  • the temperature of the filter 32 can be caused to go up by the exhaust gas of high temperature flowing into the filter 32.
  • the ECU 90 makes the amount of air passing through the cylinder 2 larger in accordance with the increasing amount of PM deposition in the filter 32.
  • the other devices, parts and so on are the same as those in the first embodiment, so the explanation thereof is omitted.
  • an amount of oxygen required for removing the PM may be small. Accordingly, in cases where the amount of PM deposition is relatively small, by shortening the valve overlap period of time, the deterioration of fuel economy can be suppressed, and the amount of toxic or harmful substances to be emitted or discharged from the internal combustion engine 1 can be reduced.
  • the amount of air passing through the cylinder 2 can be calculated according to the above-mentioned expression 1.
  • valve overlap period of time may also be made longer in accordance with the increasing amount of PM deposition in the filter 32.
  • the relation between the amount of PM deposition and the valve overlap period of time or the amount of air passing through the cylinder 2 may have been obtained in advance by experiments, simulations or the like, and stored in the ECU 90.
  • Fig. 5 is a flow chart showing a control flow or routine for valve timing according to this embodiment of the present invention.
  • the routine in this flow chart is carried out by means of the ECU 90 at each predetermined time interval.
  • step S301 the processing of step S301 is carried out after the processing of step S104.
  • step S301 the valve overlap period of time is adjusted according to the amount of PM deposition in the filter 32. That is, the valve timing of at least one of the intake valve 5 and the exhaust valve 9 is adjusted in such a manner that the larger the amount of PM deposition in the filter 32, the longer the valve overlap period of time becomes.
  • the relation between the amount of PM deposition in the filter 32 and the valve timing of the intake valve 5 or the exhaust valve 9 may have been obtained in advance by experiments, simulations or the like, and stored in the ECU 90.
  • the amount of oxygen supplied to the filter 32 is adjusted according to the amount of PM deposition in the filter 32, so that when the amount of PM deposition in the filter 32 is large, the PM can be quickly removed from the filter 32.
  • the amount of PM deposition in the filter 32 is small, the amount of air passing through the cylinder 2 can be made relatively small, so that deterioration of fuel economy can be suppressed, or an increase in the amount of toxic or harmful substances in the exhaust gas can be suppressed.
  • step S201 and step S202 can be added, similar to the flow chart shown in Fig. 4.
  • the routine advances to step S201, and then, when the processing of step S201 is completed, the routine advances to step S202.
  • the routine advances to step S103, whereas in cases where a negative determination is made, the routine advances to step S105.
  • the amount of air passing through the cylinder 2 is made larger by making the valve overlap period of time longer.
  • the ECU 90 adjusts the amount of air passing through the cylinder 2 by shifting the center of the valve overlap. In this case, it is not necessary to change the valve overlap period of time.
  • the other devices, parts and so on are the same as those in the first embodiment, so the explanation thereof is omitted.
  • the center of the valve overlap period of time is a center of a period of time from the point in time at which the intake valve 5 begins to open until the point in time at which the exhaust valve 9 is completely closed. That is, the center of the valve overlap period of time corresponds to a crank angle which is obtained by dividing, by 2, a value of the sum of a crank angle at the time the intake valve 5 begins to open and a crank angle at the time the exhaust valve 9 is completely closed. Then, in this embodiment, the center of the valve overlap period of time is matched with the time at which the flow speed of the air passing through the cylinder 2 becomes a maximum.
  • Fig. 6 is a view showing the relation between the crank angle and the pressure in the cylinder 2 (cylinder internal pressure) in the vicinity of the top dead center of exhaust stroke in the predetermined low rotation and high load region.
  • the supercharging pressure in Fig. 6 is an average value of the pressure in the intake passage 4.
  • the exhaust gas pressure in Fig. 6 is an average value of the pressure in the exhaust passage 7. In the predetermined low rotation and high load region, the supercharging pressure is higher than the exhaust gas pressure.
  • the pressure in the cylinder 2 is lower than the supercharging pressure and the exhaust gas pressure, so that gas flows from the intake passage 4 and the exhaust passage 7 into the cylinder 2.
  • valve overlap when valve overlap has occurred in the range indicated at B, air flows from the intake passage 4 into the exhaust passage 7, while passing through the cylinder 2. That is, the flow speed of the air passing through the cylinder 2 becomes a maximum within the range indicated at B. Accordingly, in this embodiment, it is configured such that the center of the valve overlap falls into the range indicated at B.
  • valve overlap may exist even in the normal mode, the purpose for that is to enhance the charging efficiency or to increase the amount of internal EGR gas, and hence, the timing of the valve overlap in the normal mode is different from that which is set in the regeneration mode.
  • the point in time at which the flow speed of the air passing through the cylinder 2 becomes a maximum can be obtained in advance through experiments, simulations, or the like.
  • the center of the valve overlap needs only to fall into the range indicated at B, but in addition, by matching the center of the valve overlap with the center of the range indicated at B, the amount of the air passing through the cylinder 2 can be made much larger.
  • the ECU 90 operates the valve timing in such a manner that in the regeneration mode, the center of the valve overlap falls into the range indicated at B in Fig. 6.
  • the valve timing may be operated in such a manner that in the regeneration mode, the center of the valve overlap matches with the center of the range indicated at B in Fig. 6.
  • the larger the amount of PM deposition the closer to the center of the range indicated at B, the center of the valve overlap may be made.
  • the center of the valve overlap needs only to be closer to the point in time at which the flow speed of the air passing through the cylinder 2 becomes a maximum, at the time of the regeneration mode rather than at the time of the normal mode.
  • the ECU 90 serves to match the point in time, at which the opening area of the intake valve 5 and the opening area of the exhaust valve 9 in the valve overlap period of time become the same with each other, with the point in time at which the flow speed of the air passing through the cylinder 2 becomes a maximum.
  • the other devices, parts and so on are the same as those in the first embodiment, so the explanation thereof is omitted.
  • Fig. 7 is a view showing the changes over time of the opening areas of the intake valve 5 and the exhaust valve 9.
  • the words "intake valve opens” in Fig. 7 indicate a point in time at which the intake valve 5 begins to open, and which becomes a start point of the valve overlap period of time.
  • the words “exhaust valve closes” in Fig. 7 indicate a point in time at which the exhaust valve 9 is completely closed, and which becomes an end point of the valve overlap period of time.
  • both of the intake valve 5 and the exhaust valve 9 are open, but during this valve overlap period of time, the opening area of the intake valve 5 becomes larger in a gradual manner, and the opening area of the exhaust valve 9 becomes smaller in a gradual manner. For this reason, there exists a point in time D at which the opening area of the intake valve 5 and the opening area of the exhaust valve 9 become the same with each other.
  • the opening area of the exhaust valve 9 becomes relatively small, so that the resistance of air at the time of passing through the exhaust valve 9 is relatively large.
  • the amount of air passing through cylinder 2 is limited by the exhaust valve 9. That is, the amount of air passing through the cylinder 2 is limited by one of the intake valve 5 and the exhaust valve 9, of which the opening area is smaller than the other. Accordingly, when the opening areas of the intake valve 5 and the exhaust valve 9 are equal to each other, resistance at the time of air passing through the cylinder 2 becomes the smallest, so that it becomes the easiest for air to pass through the cylinder 2.
  • the amount of air passing through the cylinder 2 becomes the largest at the point in time D at which the opening areas of the intake valve 5 and the exhaust valve 9 become the same with each other. At this time, if the flow speed of air is the highest, a larger amount of air will pass through the cylinder 2. Accordingly, by bringing the point in time D, at which the opening area of the intake valve 5 and the opening area of the exhaust valve 9 during the valve overlap period of time become the same with each other, close to the point in time at which the flow speed of air passing through the cylinder 2 becomes a maximum, it is possible to make large the amount of air passing through the cylinder 2.
  • the ECU 90 operates the valve timing in such a manner that the point in time D, at which the opening area of the intake valve 5 and the opening area of the exhaust valve 9 during the valve overlap period of time become the same with each other, falls into the range indicated at B in Fig. 6.
  • the valve timing may be operated in such a manner that the point in time D, at which the opening area of the intake valve 5 and the opening area of the exhaust valve 9 become the same with each other in the regeneration mode, may be matched with the center of the range indicated at B in Fig. 6.
  • the larger the amount of PM deposition the closer to the center of the range indicated at B, the point in time D at which the opening area of the intake valve 5 and the opening area of the exhaust valve 9 become the same with each other may be made.
  • the response request is a request for increasing engine output power with respect to an increase in the accelerator opening degree in a quick manner.
  • the response request can also be said to be a request for causing the supercharging pressure to go up in a quick manner.
  • the other devices, parts and so on are the same as those in the first embodiment, so the explanation thereof is omitted.
  • the ECU 90 causes valve overlap, or makes the valve overlap period of time longer than in the normal mode.
  • the control mode of valve timing is set to the regeneration mode.
  • valve overlap period of time the amount of air passing through the cylinder 2 is increased, so that the amount of gas passing through the turbine 52 is increased. For this reason, the rise or increase of the number of revolutions per unit time of the turbine 52 is promoted, so the supercharging pressure goes up quickly.
  • the amount of air passing through the cylinder 2 be large, even after the supercharging pressure has become high to a sufficient extent.
  • the regeneration mode is continued after the supercharging pressure has become high to a sufficient extent, as mentioned above, there is a fear of causing an increase in the harmful substances in the exhaust gas, etc.
  • the regeneration mode is continued even after the supercharging pressure has become high to a sufficient extent. That is, priority is given to the regeneration of the filter 32.
  • the amount of PM deposition in the filter 32 is less than the second predetermined amount, when the response request has ceased to exist, a shift is made from the regeneration mode to the normal mode, in order to suppress an increase in harmful substances in the exhaust gas, etc.
  • the time when the response request has ceased to exist is a time when the supercharging pressure has become high to a sufficient extent (i.e., when the supercharging pressure has reached a predetermined pressure).
  • the second predetermined amount referred to herein is an amount of PM deposition which is larger than the predetermined amount used in the above-mentioned step S102, and at which there is a need to remove the PM from the filter 32 in a quick manner.
  • the predetermined amount used in the above-mentioned step S102 is given a certain amount of margin, as compared with the second predetermined amount, and hence, even if an actual amount of PM deposition reaches the predetermined amount, a problem does not necessarily occur immediately.
  • the second predetermined amount has an amount of margin of the amount of PM deposition which is set to be less than that for the predetermined amount, and hence, it is desirable that in cases where the actual amount of PM deposition has reached the second predetermined amount, the regenerate of the filter 32 should be carried out quickly.
  • the second predetermined amount can be decided according to which of the regeneration of the filter 32, and the reduction of the harmful substances in the exhaust gas, etc., is given priority to what extent.
  • the second predetermined amount can be obtained in advance through experiments, simulations, or the like.
  • Fig. 8 is a flow chart showing a control flow or routine for valve timing according to this embodiment of the present invention.
  • the routine in this flow chart is carried out by means of the ECU 90 at each predetermined time interval.
  • step S401 the processing of step S401 is carried out after the processing of step S104.
  • the ECU 90 determines whether there is any response request. For example, when the extent of increase of the accelerator opening degree is equal to or more than a predetermined extent and when the supercharging pressure is less than a predetermined pressure, the ECU 90 makes a determination that there is a response request.
  • the predetermined extent referred to herein is an extent of increase of the accelerator opening degree with which it can be judged that the driver of the vehicle requires acceleration, and the predetermined pressure is a supercharging pressure with which it can be judged that the supercharging pressure has become high to a sufficient extent.
  • step S401 in cases where the accelerator opening degree is fully opened, a determination may be made that there is a response request.
  • the routine advances to step S402 in cases where a negative determination is made, the routine advances to step S403.
  • step S402 the ECU 90 determines whether the amount of PM deposition in the filter 32 is equal to or more than the second predetermined amount.
  • the second predetermined amount is a value which is larger than the predetermined amount used in step S102, and has been obtained in advance by experiments, simulations, or the like. In this step, it is determined whether it is desirable to regenerate the filter 32 quickly. In cases where an affirmative determination is made in step S402, the routine advances to step S403, whereas in cases where a negative determination is made, the routine advances to step S404.
  • step S403 the ECU 90 adjusts valve timing so that priority is given to the regeneration of the filter 32.
  • the amount of PM deposition is equal to or more than the second predetermined amount (i.e., in cases where an affirmative determination is made in step S402)
  • step S404 the ECU 90 adjusts valve timing so that priority is given to the response request.
  • the amount of PM deposition is less than the second predetermined amount (i.e., in cases where a negative determination is made in step S402)
  • the PM trapping capacity of the filter 32 still has a margin.
  • a shift is made from the regeneration mode to the normal mode. That is, in cases where the supercharging pressure has become high to a sufficient extent, the length of the valve overlap period of time is made shorter, or the center of the valve overlap period of time is made away from the point in time at which the flow speed of air at the time of passing through the cylinder 2 becomes a maximum. As a result of this, it is possible to suppress an increase in harmful substances in the exhaust gas.
  • priority is given to the regeneration of the filter 32, thus making it possible to suppress the rise or increase in the pressure of the exhaust gas.
  • priority is given to a response request, so that an increase in harmful substances in the exhaust gas can be suppressed.
  • step S201 and step S202 can be added, similar to the flow chart shown in Fig. 4.
  • the routine advances to step S201, and then, when the processing of step S201 is completed, the routine advances to step S202. Then, in cases where an affirmative determination is made in step S202, the routine advances to step S103, and on the other hand, in cases where a negative determination is made, the routine advances to step S105.
  • step S301 can also be added, similar to the flow chart shown in Fig. 5.
  • the routine advances to step S301, and then, when the processing of step S301 is completed, the routine advances to step S401.
PCT/JP2015/000234 2014-01-20 2015-01-20 Exhaust gas purification apparatus for an internal combustion engine WO2015107911A1 (en)

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CN110360016A (zh) * 2018-03-26 2019-10-22 丰田自动车株式会社 内燃机的控制装置及方法
US10823095B2 (en) 2018-03-29 2020-11-03 Toyota Jidosha Kabushiki Kaisha Controller and control method for internal combustion engine
CN115263578A (zh) * 2022-07-22 2022-11-01 中国第一汽车股份有限公司 汽油机颗粒捕捉器被动再生的控制方法、装置及车辆

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US20040103648A1 (en) * 2002-12-03 2004-06-03 Opris Cornelius N. Method and apparatus for PM filter regeneration
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EP2562400A1 (fr) * 2011-08-23 2013-02-27 Peugeot Citroën Automobiles Sa Procédé de régénération d'un filtre à particules de moteur à combustion interne

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US20030221421A1 (en) * 2002-06-04 2003-12-04 Xinqun Gui Control strategy for regenerating a particulate filter in an exhaust system of an engine having a variable valve actuation mechanism
US20040103648A1 (en) * 2002-12-03 2004-06-03 Opris Cornelius N. Method and apparatus for PM filter regeneration
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CN110360016A (zh) * 2018-03-26 2019-10-22 丰田自动车株式会社 内燃机的控制装置及方法
US10794247B2 (en) 2018-03-26 2020-10-06 Toyota Jidosha Kabushiki Kaisha Controller and control method for internal combustion engine
CN110360016B (zh) * 2018-03-26 2022-04-12 丰田自动车株式会社 内燃机的控制装置及方法
US10823095B2 (en) 2018-03-29 2020-11-03 Toyota Jidosha Kabushiki Kaisha Controller and control method for internal combustion engine
CN115263578A (zh) * 2022-07-22 2022-11-01 中国第一汽车股份有限公司 汽油机颗粒捕捉器被动再生的控制方法、装置及车辆
CN115263578B (zh) * 2022-07-22 2024-03-19 中国第一汽车股份有限公司 汽油机颗粒捕捉器被动再生的控制方法、装置及车辆

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