초록 ▼

An opening is provided for an exhaust bypass pipe that bypasses an exhaust turbine of an exhaust turbine supercharger. According to the opening, an exhaust gas amount bypassing the exhaust turbine is calculated. An exhaust gas amount supplied to the exhaust turbine is found by subtracting the waste-

An opening is provided for an exhaust bypass pipe that bypasses an exhaust turbine of an exhaust turbine supercharger. According to the opening, an exhaust gas amount bypassing the exhaust turbine is calculated. An exhaust gas amount supplied to the exhaust turbine is found by subtracting the waste-gate-valve-passing gas amount from an intake air amount (exhaust gas amount) detected by the air flow meter. A rotational speed of the exhaust turbine is calculated from this turbine-supplied gas amount. An estimated boost pressure is calculated from this rotational speed of the exhaust turbine. Consequently, a boost pressure can be accurately estimated without using a boost pressure sensor even under such conditions as to disable detection of boost pressures or degrade the detection accuracy in a system using a conventional boost pressure sensor.

대표청구항 ▼

What is claimed is: 1. A boost pressure estimation apparatus for an internal combustion engine with a super charger and a waste gate valve, the supercharger using an exhaust pressure to drive an exhaust turbine provided for an exhaust pipe of an internal combustion engine and to drive a compressor

What is claimed is: 1. A boost pressure estimation apparatus for an internal combustion engine with a super charger and a waste gate valve, the supercharger using an exhaust pressure to drive an exhaust turbine provided for an exhaust pipe of an internal combustion engine and to drive a compressor provided for an intake pipe to supply air into a cylinder, the waste gate valve opening and/or closing an exhaust bypass pipe to bypass the exhaust turbine, the boost pressure estimation apparatus comprising: a means for detecting intake air amount for detecting an intake air amount of an internal combustion engine; a turbine-supplied gas amount calculation means for calculating an exhaust gas amount supplied to the exhaust turbine (hereafter referred to as a "turbine-supplied gas amount") based on an intake air amount detected by the means for detecting intake air amount and opening of the waste gate valve; and a boost pressure estimation means for calculating an estimated value of the supercharger boost pressure (hereafter referred to as an "estimated boost pressure") based on the turbine-supplied gas amount. 2. The boost pressure estimation apparatus according to claim 1, wherein the turbine-supplied gas amount calculation means, during acceleration or deceleration of an internal combustion engine, calculates a delay time constant due to the inertia of the exhaust turbine based on an intake air amount detected by the means for detecting intake air amount and corrects the turbine-supplied gas amount based on the delay time constant. 3. The boost pressure estimation apparatus according to claim 1, further comprising: an inter-cooler cooling an intake air pressurized by the supercharger, wherein the boost pressure estimation means calculates an intake pressure loss due to the inter-cooler based on an operation state of an internal combustion engine and corrects the estimated boost pressure based on the intake pressure loss. 4. The boost pressure estimation apparatus according to claim 1, further comprising: an air bypass valve opening and/or closing an intake bypass pipe which bypasses the compressor, wherein the boost pressure estimation means corrects the estimated boost pressure based on opening of the air bypass valve. 5. The boost pressure estimation apparatus according to claim 1, wherein each of a plurality of exhaust pipes provided for a plurality of cylinder groups of an internal combustion engine is provided with the supercharging system and an air-fuel ratio sensor to detect an air-fuel ratio of exhaust gas; wherein air-fuel ratio feedback control means is provided for calculating an air-fuel ratio feedback correction amount so as to establish a match between an exhaust gas air-fuel ratio detected by the air-fuel ratio sensor for each cylinder group and a target air-fuel ratio; and wherein the turbine-supplied gas amount calculation means calculates the turbine-supplied gas amount for each exhaust pipe based on an intake air amount detected by the means for detecting intake air amount, opening of the waste gate valve, and an air-fuel ratio feedback correction amount in each cylinder group. 6. The boost pressure estimation apparatus according to claim 1, wherein boost pressure control means is provided for calculating a target boost pressure based on an operation state of an internal combustion engine and controlling opening of the waste gate valve so that the estimated boost pressure matches the target boost pressure. 7. The boost pressure estimation apparatus according to claim 1, wherein the boost pressure estimation means calculates a rotational speed of the exhaust turbine based on the turbine-supplied gas amount and calculates the estimated boost pressure based on a rotational speed of the exhaust turbine. 8. The boost pressure estimation apparatus according to claim 7, further comprising: an air bypass valve opening and/or closing an intake bypass pipe which bypasses the compressor, wherein the boost pressure estimation means calculates the estimated boost pressure based on a rotational speed of the exhaust turbine and, at this time, changes relationship between the rotational speed of the exhaust turbine and the estimated boost pressure according to an operation state of the air bypass valve to correct the estimated boost pressure. 9. A boost pressure estimation apparatus for an internal combustion engine with a super charger and a waste gate valve, the supercharger using an exhaust pressure to drive an exhaust turbine provided for an exhaust pipe of an internal combustion engine and to drive a compressor provided for an intake pipe to supply air into a cylinder, the waste gate valve opening and/or closing an exhaust bypass pipe to bypass the exhaust turbine, the boost pressure estimation apparatus comprising: an intake air amount detector; a turbine-supplied gas amount calculator that calculates an exhaust gas amount supplied to the exhaust turbine based on an intake air amount detected by the intake air amount detector and an opening amount of the waste gate valve; and an estimated supercharger boost pressure calculator that calculates an estimated value of the supercharger boost pressure based on the turbine-supplied gas amount. 10. The boost pressure estimation apparatus according to claim 9, further comprising: an inter-cooler cooling an intake air pressurized by the supercharger, wherein the estimated boost pressure calculator calculates an intake pressure loss due to the inter-cooler based on an operation state of an internal combustion engine and corrects the estimated boost pressure based on the intake pressure loss. 11. The boost pressure estimation apparatus according to claim 9, further comprising: an air bypass valve opening and/or closing an intake bypass pipe which bypasses the compressor, wherein the estimated boost pressure calculator corrects the estimated boost pressure based on opening of the air bypass valve. 12. The boost pressure estimation apparatus according to claim 9, further comprising: an air bypass valve opening and/or closing an intake bypass pipe which bypasses the compressor, wherein the estimated boost pressure calculator calculates a rotational speed of the exhaust turbine based on the turbine-supplied gas amount and calculates the estimated boost pressure based on a rotational speed of the exhaust turbine, and wherein the estimated boost pressure calculator calculates the estimated boost pressure based on a rotational speed of the exhaust turbine and, at this time, changes relationship between the rotational speed of the exhaust turbine and the estimated boost pressure according to an operation state of the air bypass valve to correct the estimated boost pressure. 13. A method of estimating boost pressure for an internal combustion engine with a super charger and a waste gate valve, the supercharger using an exhaust pressure to drive an exhaust turbine provided for an exhaust pipe of an internal combustion engine and to drives a compressor provided for an intake pipe to supply air into a cylinder, the waste gate valve opening and/or closing an exhaust bypass pipe to bypass the exhaust turbine, the boost pressure estimation method comprising: detecting intake air amount for detecting an intake air amount of an internal combustion engine; calculating an exhaust gas amount supplied to the exhaust turbine (hereafter referred to as a "turbine-supplied gas amount") based on a detected intake air amount and an opening amount of the waste gate valve; and calculating an estimated value of the supercharger boost pressure (hereafter referred to as an "estimated boost pressure") based on the turbine-supplied gas amount. 14. The method according to claim 13, further comprising: calculating a rotational speed of the exhaust turbine based on the turbine-supplied gas amount, and calculating the estimated boost pressure based on a rotational speed of the exhaust turbine. 15. The method according to claim 13, further comprising: calculating, during acceleration or deceleration of an internal combustion engine, a delay time constant due to the inertia of the exhaust turbine based on a detected intake air amount, and correcting the turbine-supplied gas amount based on the delay time constant. 16. The method according to claim 13, comprising: an inter-cooler cooling an intake air pressurized by the supercharger, calculating intake pressure loss due to the inter-cooler based on an operation state of an internal combustion engine, and correcting the estimated boost pressure based on the intake pressure loss. 17. The method according to claim 13, comprising: an air bypass valve opening and/or closing an intake bypass pipe which bypasses the compressor, and correcting the estimated boost pressure based on opening of the air bypass valve. 18. The method according to claim 13, comprising: an air bypass valve opening and/or closing an intake bypass pipe which bypasses the compressor, calculating the estimated boost pressure based on a rotational speed of the exhaust turbine and, at this time, changes relationship between the rotational speed of the exhaust turbine and the estimated boost pressure according to an operation state of the air bypass valve to correct the estimated boost pressure. 19. A method according to claim 13, wherein each of a plurality of exhaust pipes provided for a plurality of cylinder groups of an internal combustion engine is provided with the supercharging system and an air-fuel ratio sensor to detect an air-fuel ratio of exhaust gas; comprising: calculating an air-fuel ratio feedback correction amount so as to establish a match between an exhaust gas air-fuel ratio detected by the air-fuel ratio sensor for each cylinder group and a target air-fuel ratio; and calculating the turbine-supplied gas amount for each exhaust pipe based on an intake air amount detected by the means for detecting intake air amount, opening of the waste gate valve, and an air-fuel ratio feedback correction amount in each cylinder group. 20. A method according to claim 13, further comprising calculating a target boost pressure based on an operation state of an internal combustion engine and controlling opening of the waste gate valve so that the estimated boost pressure matches the target boost pressure.