Ambient Condition Responsive (e.g., Atmospheric Temperature, Atmospheric Pressure) Patents (Class 123/568.22)
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Patent number: 7269466Abstract: The present invention aims to control elements to improve operation efficiency of a plant based on a correlation value of the past accumulated data. According to the invention, an optimal operation controller obtains a correlation between a state of a predetermined process and each element based on an operation status of the plant to be controlled, storing the correlation in a correlation table, and compute an operation efficiency for each element based on the operation status of the plant. Also, the operation controller has a categorization efficiency table for storing the computed operation efficiency of the predetermined process. The operation controller refers to the categorization efficiency table based on a data input from the plant, and outputs an instruction to control the each element accordingly.Type: GrantFiled: July 8, 2003Date of Patent: September 11, 2007Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Norio Hirai
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Patent number: 7195007Abstract: An intake pipe downstream of a throttle valve is interconnected with an exhaust pipe via an EGR supply pipe and an EGR control valve is disposed in the EGR supply pipe. An engine load ratio (KLoff) in the engine steady operation with the EGR gas being not supplied, and another engine load ratio KLon in the engine steady operation with the EGR gas being supplied are expressed with respective linear functions of an intake pipe pressure (Pm) and stored in advance. The intake pipe pressure (Pm) is detected, KLoff and KLon are calculated from the detected intake pipe pressure (Pm) using the linear function expressions and, then, a difference between these values ?KL (=KLoff?KLon) is calculated. Based on the difference (?KL), the EGR control valve passing-through gas amount, which is an amount of the EGR gas passing through the EGR control valve, is calculated.Type: GrantFiled: December 8, 2003Date of Patent: March 27, 2007Assignee: Toyota Jidosha Kabushiki KaishaInventors: Harufumi Muto, Daisuke Kobayashi, Yuichiro Ido
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Patent number: 7174713Abstract: An engine management system uses physically based models to determine the composition and mass of the fresh air/exhaust gas mixture suctioned by an internal combustion engine. The models are closely coupled to each other in a partial manner and are used to simulate the filling of the combustion chamber with the suctioned fresh air/waste gas mixture in order to simulate the flow of the mass of re-circulating exhaust gas, the behavior of the exhaust gas manifold upstream and downstream from a turbine, the storage behavior of the intake manifold, and the behavior of the intake pipe or inlet manifold whereby the fresh air/exhaust gas mixture is fed to the combustion engine from a corresponding mixing point where the suctioned fresh air is mixed with the exhaust gas re-circulated via the exhaust gas re-circulation line. As a result, a plurality of additional state variables can be determined without additional sensors.Type: GrantFiled: May 20, 2004Date of Patent: February 13, 2007Assignee: Volkswagen AktiengesellschaftInventors: Hans-Georg Nitzke, Thorsten Rebohl, Jens Jeschke
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Patent number: 7177754Abstract: In an electronic control unit 31, a duty conversion map 41 from which a driving duty in energizing and driving an electromagnetic coil, not shown, of an electromagnetic vacuum adjustment valve 12 on the basis of a variable equivalent to target quantity of feedback of exhaust gas, for example, the magnitude of a desired negative pressure to a negative pressure output port (not shown) of the electromagnetic vacuum adjustment valve 12, and a duty correction map 42 from which a correction value for the driving duty is acquired on the basis inputted battery voltage and engine cooling water temperature, are provided. The driving duty is multiplied by the correction value acquired from the duty correction map 42, and on the basis of the corrected driving duty, energization to the electromagnetic vacuum adjustment valve 12 is performed by a driving circuit 26.Type: GrantFiled: June 13, 2005Date of Patent: February 13, 2007Assignee: Bosch Automotive Systems CorporationInventors: Junichi Kaneko, Toshiko Okazaki
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Patent number: 7174250Abstract: In a method of determining the quantity of exhaust gas recirculation for an internal combustion engine having exhaust gas recirculation, the exhaust gas recirculation quantity (rAGR, mAGR) is determined from an exhaust gas temperature (Texhaust), a fresh gas temperature (Tair2), a fresh gas quantity (mair) and/or a volumetric efficiency (?). The fresh gas temperature (Tair2) is determined by a fresh gas temperature model (15) which is adaptively adjusted in response to influencing parameters relevant to the fresh gas temperature.Type: GrantFiled: August 26, 2003Date of Patent: February 6, 2007Assignee: DaimlerChrysler AGInventors: Christian Barba, Martin Dietz, Guenter Moll
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Patent number: 7143580Abstract: A system and method for controlling an internal combustion engine, having an exhaust recirculation (EGR) system and a charge air cooler, to prevent overheating the charge air cooler. The system calculates the output temperature of a turbocharger compressor as a function of ambient air temperature, air pressure, air mass flow rate, and turbo speed by processing an equation and controls the engine to modify charge air flow to reduce the output temperature of the turbocharger compressor if that temperature exceeds that of a determined crucial temperature above which charge air cooler damage could occur.Type: GrantFiled: October 22, 2004Date of Patent: December 5, 2006Assignee: Detroit Diesel CorporationInventor: Ping Ge
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Patent number: 7104228Abstract: A system and method for utilizing a humidity sensor with an internal combustion engine of a vehicle is described. Specifically, information from the humidity sensor is used to adjust a desired air-fuel ratio to reduce engine misfire while improving vehicle fuel economy. Further, such information is also used to adjust timing and/or lift of the valve in the engine cylinder. Finally, diagnostic routines are also described.Type: GrantFiled: May 18, 2005Date of Patent: September 12, 2006Assignee: Ford Global Technologies, LLCInventor: Michael J. Cullen
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Patent number: 6964161Abstract: A induction exhaust system, for an internal combustion engine, capable of the multi step processes of 1) scavenging the chamber of exhaust gases and free radicals, 2) breaking the scavenge vacuum wave behind each energetic exhaust pulse, releasing said free radicals and the overscavenged air fuel vacuumed from the intake manifold during valve overlap, and 3) induction of such free radicals, unburned fuel, and fresh matter including atmospheric air.Type: GrantFiled: September 30, 2002Date of Patent: November 15, 2005Inventor: Monty Allen Campbell
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Patent number: 6954693Abstract: A system for controlling exhaust emissions produced by an internal combustion engine includes an engine controller having an emission manager configured to produce a base emission level cap command, corresponding to a maximum allowable emission level of the engine, as a function of at least altitude and ambient temperature. The emission manager may also include one or more auxiliary emission control devices (AECDs), and the emission manager is further operable in such cases to determine a maximum allowable emission level associated with each active AECD. A final emission level cap command is determined as a function of the base emission level cap command and the maximum allowable emission level associated with each active AECD. The emission manager is further operable to produce a protection state data structure that includes information relating to the operational status of each AECD.Type: GrantFiled: March 30, 2004Date of Patent: October 11, 2005Assignee: Cummins, Inc.Inventors: Larry J. Brackney, Thomas A. Dollmeyer, George A. Brunemann
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Patent number: 6934621Abstract: A control for an internal combustion engine that includes an exhaust gas recirculation system predicts at least one of the intake manifold temperature in EGR mode or an intake manifold pressure in EGR mode, but preferably both, during Boost mode operation. The predictions are relied upon to calculate an intake manifold critical temperate in EGR, at which condensation would occur. The control then compares the predicted temperate value with the calculated intake manifold critical temperature, and if the predicted value exceeds the calculated temperature, the control commands re-entry into exhaust gas recirculation mode.Type: GrantFiled: July 25, 2003Date of Patent: August 23, 2005Assignee: Detroit Diesel CorporationInventors: Sameer Bhargava, Ravishankar Ramamurthy, Brian A. Lewallen
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Patent number: 6918362Abstract: A system and method for utilizing a humidity sensor with an internal combustion engine of a vehicle is described. Specifically, information from the humidity sensor is used to adjust a desired air-fuel ratio to reduce engine misfire while improving vehicle fuel economy. Further, such information is also used to adjust timing and/or lift of the valve in the engine cylinder. Finally, diagnostic routines are also described.Type: GrantFiled: October 2, 2003Date of Patent: July 19, 2005Assignee: Ford Global Technologies, LLCInventor: Michael J. Cullen
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Patent number: 6868329Abstract: A control method of an EGR system of an engine capable of effectively performing an EGR control at a time of rapid acceleration. For this purpose, an intake air flow rate of the engine is obtained, and from a target EGR valve opening degree and a difference in pressure in front of and behind the EGR valve, a virtual EGR gas flow rate is arithmetically operated. A virtual EGR rate is obtained from the intake air flow rate, the fuel flow rate and the virtual EGR gas flow rate, and a difference from or a ratio to a target EGR rate obtained from the engine speed and the fuel flow rate is obtained. A command EGR valve opening degree is obtained from an EGR valve opening degree correction coefficient obtained from the difference or the ratio, and the target EGR valve opening degree, whereby the EGR vale is driven.Type: GrantFiled: October 14, 2003Date of Patent: March 15, 2005Assignee: Komatsu Ltd.Inventors: Takumi Ito, Yasuyuki Onodera, Kanji Namimatsu, Shuki Akushichi, Koichi Okaya
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Patent number: 6826903Abstract: An exhaust gas recirculation (EGR) system of an internal combustion engine has an EGR cooler in an EGR passage connecting an exhaust manifold with an intake manifold. The EGR cooler cools EGR gas recirculated through the EGR passage. Cooling performance detecting means included in an electronic control unit (ECU) determines that cooling performance of the EGR cooler is degraded when intake pressure measured by an intake pressure sensor is lower than a normal intake pressure by at least a predetermined value. When the degradation of the cooling performance is detected, cooling performance regeneration controlling means included in the ECU increases the temperature inside the EGR cooler by heating the exhaust gas to eliminate soot or unburned hydrocarbon by oxidization. Thus, the cooling performance of the EGR cooler is regenerated.Type: GrantFiled: May 19, 2003Date of Patent: December 7, 2004Assignee: Denso CorporationInventors: Shigeto Yahata, Makoto Saito, Masumi Kinugawa, Kiyonori Sekiguchi, Tsukasa Kuboshima
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Patent number: 6820599Abstract: The present invention is a dual-stage fuel injection strategy for compression ignition engines in which 15-40% of the fuel is injected into the combustion chamber no later than about −20 to −30 CA ATDC and as early as IVC. The remaining fuel is then injected in one or more fuel pulses, none of which start before about −20 to −30 CA ATDC. The fuel injected early in the compression stroke forms a lean mixture that burns with low soot and low NOx emissions. The combustion of that fuel serves to increase in-cylinder temperature such that the ignition delay of subsequent fuel injection pulses is short. This mode is utilized when it is predicted that a NOx spike is imminent. Various other alternative methods for reducing NOx spikes are also disclosed such as specialized EGR systems that can provide EGR with low manifold vacuum.Type: GrantFiled: February 3, 2003Date of Patent: November 23, 2004Assignee: Ford Global Technologies, LLCInventors: Eric Matthew Kurtz, John H. Vanderslice
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Patent number: 6804588Abstract: A system for discriminating malfunction of a radiator of an internal combustion engine, in which conditions for execution of malfunction discrimination of the radiator are decided to be established, when a decline amount of outside air temperature is less than a threshold value, and the malfunction discrimination is conducted by comparing an estimated and detected coolant temperatures with predetermined values. In the system, making the decision that the conditions are not established is prevented, utilizing a parameter related to a quantity of intake air. With this, it becomes possible to inhibit decisions finding that the conditions are not established in certain cases in which such a decision would ordinarily be unreasonably made, such as when the internal combustion engine is started while still insufficiently soaked, etc.Type: GrantFiled: October 11, 2002Date of Patent: October 12, 2004Assignee: Honda Giken Kogyo Kabushiki KaishaInventors: Hideyuki Oki, Takashi Isobe
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Patent number: 6748936Abstract: An internal combustion engine is provided with a VVT mechanism capable of adjusting overlap period in which both intake and exhaust valves are open. The internal combustion engine is also provided with a recirculation mechanism that recirculates exhaust gas to the intake side. An EGR map from which internal EGR amount based on the VVT mechanism and external EGR amount based on the recirculation mechanism are derived in accordance with engine speed and engine torque is prepared. The EGR map is realized as a four-dimensional map that also takes engine intake air temperature and engine coolant temperature into account. By performing EGR control in consideration of these parameters, the occurrence of knocking during EGR control can be suppressed, and an improvement in fuel consumption and the like can be achieved with certainty.Type: GrantFiled: April 17, 2003Date of Patent: June 15, 2004Assignee: Toyota Jidosha Kabushiki KaishaInventors: Shigeki Kinomura, Kazuhisa Mogi, Hirofumi Kubota
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Patent number: 6725848Abstract: An exhaust gas recirculation system for a compression ignition engine is provided wherein the exhaust gas recirculation is shut off depending upon the sensed or calculated humidity in the intake manifold relative to the dew point of the exhaust/intake air mixture. The humidity of the exhaust/intake air mixture may be measured in the intake manifold, charge air mixer or the ambient humidity may be sensed. If humidity is measured in the air charge mixer or in the ambient air, other factors such as engine speed and load, intake manifold pressure, EGR flow and air/fuel ratio may be used to calculate the humidity in the intake manifold. When the temperature of the mixture in the intake manifold is less than the dew point of the mixture, the engine control strategy may be shut off the EGR to prevent condensation in the exhaust gas recirculation system or engine.Type: GrantFiled: January 18, 2002Date of Patent: April 27, 2004Assignee: Detroit Diesel CorporationInventors: Ravishankar Ramamurthy, Sameer Bhargara, Phillip F. Rimnac
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Patent number: 6715476Abstract: A system and method for controlling a multi-cylinder internal combustion engine having at least one automatically controllable airflow actuator and an exhaust gas recirculation (EGR) system including an EGR valve include determining a desired manifold pressure based at least in part on position of the automatically controllable airflow actuator and controlling the EGR valve such that a measured manifold pressure approaches the desired manifold pressure. In one embodiment, the automatically controllable airflow actuators include a charge motion control valve and a variable cam timing device. In other embodiments, the automatically controllable airflow actuators may include variable valve lift devices, variable valve timing devices, or any other device that affects the residual exhaust gases within the cylinders.Type: GrantFiled: April 12, 2002Date of Patent: April 6, 2004Assignee: Ford Global Technologies LLCInventors: Alexander Yuri Gopp, John Ottavio Michelini
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Patent number: 6708678Abstract: The invention provides an electronic control device for an internal combustion engine and a control method thereof in which more stable control is attained on the internal combustion engine in association with change in EGR amount due to change in atmospheric pressure.Type: GrantFiled: May 14, 2001Date of Patent: March 23, 2004Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Hideki Hagari
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Patent number: 6705301Abstract: A combustion manager portion of an engine controller is responsive to ambient air density and engine temperature signals to schedule charge flow and EGR fraction commands. The combustion manager includes a data structure determination block operable to select an appropriate engine speed/engine fueling data structure based on air density and engine temperature information as well as on desired emissions level and engine operating state (i.e., steady state or transient) information. Charge flow and EGR fraction determination blocks are, in turn, responsive to current engine speed and engine fueling information to produce compute the EGR fraction and charge flow commands as a function of the selected engine speed/engine fueling data structures.Type: GrantFiled: January 29, 2002Date of Patent: March 16, 2004Assignee: Cummins, Inc.Inventors: Thomas A. Dollmeyer, Larry J. Brackney, George A. Brunemann, Steve Charlton
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Patent number: 6681171Abstract: A system and method for controlling an internal combustion engine to reduce or eliminate formation of EGR condensate monitor current ambient and operating conditions to determine whether conditions are favorable for condensation of EGR gases, and control the engine accordingly to avoid condensation, preferably by increasing the intake manifold temperature. The intake manifold temperature may be increased by redirecting some or all of the EGR flow to avoid the EGR cooler. Alternatively, or in combination, some or all of the charge air may be redirected to bypass the charge air cooler and/or redirected from the outlet of the turbocharger compressor to the intake, effectively increasing the intake air temperature and resulting in a corresponding increase of the intake manifold temperature. Conditions favorable for condensation may be determined based on engine speed and load, ambient temperature, manifold pressure, scheduled or actual EGR flow rate and scheduled or actual air/fuel ratio.Type: GrantFiled: December 18, 2001Date of Patent: January 20, 2004Assignee: Detroit Diesel CorporationInventors: Phillip F. Rimnac, Ravishankar Ramamurthy, Sameer Bhargava
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Patent number: 6659095Abstract: A method for controlling an engine during sensor degradation uses a remaining active sensor. The engine has an exhaust gas recirculation system utilizing pressure sensors upstream and downstream of an orifice. The downstream pressure sensor is coupled to the engine intake manifold and is also used for engine air-fuel ratio control.Type: GrantFiled: June 19, 2001Date of Patent: December 9, 2003Assignee: Ford Global Technologies, LLCInventors: Allan J. Kotwicki, Freeman Carter Gates, Hossein Bina
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Patent number: 6647972Abstract: A state determining apparatus for an exhaust gas recirculation system is provided for appropriately determining the state of an exhaust gas recirculation system including an EGR passage. An exhaust gas recirculation system is arranged in an exhaust system of an internal combustion engine including an EGR passage for recirculating a portion of exhaust gases to an intake system in accordance with an operating state of the internal combustion engine. The state determining apparatus comprises a humidity sensor arranged in the EGR passage for detecting a humidity within the EGR passage, and an ECU for determining the state of the exhaust gas recirculation system based on a result detected by the humidity sensor.Type: GrantFiled: October 12, 2001Date of Patent: November 18, 2003Assignee: Honda Giken Kogyo Kabushiki KaishaInventors: Masahiro Sato, Yoshihisa Iwaki, Masaki Ueno, Shusuke Akazaki, Yasuyuki Miyahara
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Publication number: 20030209234Abstract: An internal combustion engine is provided with a VVT mechanism capable of adjusting overlap period in which both intake and exhaust valves are open. The internal combustion engine is also provided with a recirculation mechanism that recirculates exhaust gas to the intake side. An EGR map from which internal EGR amount based on the VVT mechanism and external EGR amount based on the recirculation mechanism are derived in accordance with engine speed and engine torque is prepared. The EGR map is realized as a four-dimensional map that also takes engine intake air temperature and engine coolant temperature into account. By performing EGR control in consideration of these parameters, the occurrence of knocking during EGR control can be suppressed, and an improvement in fuel consumption and the like can be achieved with certainty.Type: ApplicationFiled: April 17, 2003Publication date: November 13, 2003Applicant: Toyota Jidosha Kabushiki KaishaInventors: Shigeki Kinomura, Kazuhisa Mogi, Hirofumi Kubota
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Publication number: 20030140906Abstract: A combustion manager portion of an engine controller is responsive to ambient air density and engine temperature signals to schedule charge flow and EGR fraction commands. The combustion manager includes a data structure determination block operable to select an appropriate engine speed/engine fueling data structure based on air density and engine temperature information as well as on desired emissions level and engine operating state (i.e., steady state or transient) information. Charge flow and EGR fraction determination blocks are, in turn, responsive to current engine speed and engine fueling information to produce compute the EGR fraction and charge flow commands as a function of the selected engine speed/engine fueling data structures.Type: ApplicationFiled: January 29, 2002Publication date: July 31, 2003Inventors: Thomas A. Dollmeyer, Larry J. Brackney, George A. Brunemann
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Publication number: 20030136390Abstract: An exhaust gas recirculation system for a compression ignition engine is provided wherein the exhaust gas recirculation is shut off depending upon the sensed or calculated humidity in the intake manifold relative to the dew point of the exhaust/intake air mixture. The humidity of the exhaust/intake air mixture may be measured in the intake manifold, charge air mixer or the ambient humidity may be sensed. If humidity is measured in the air charge mixer or in the ambient air, other factors such as engine speed and load, intake manifold pressure, EGR flow and air/fuel ratio may be used to calculate the humidity in the intake manifold. When the temperature of the mixture in the intake manifold is less than the dew point of the mixture, the engine control strategy may be shut off the EGR to prevent condensation in the exhaust gas recirculation system or engine.Type: ApplicationFiled: January 18, 2002Publication date: July 24, 2003Applicant: Detroit Diesel CorporationInventors: Ravishankar Ramamurthy, Sameer Bhargara, Phillip F. Rimnac
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Publication number: 20030114978Abstract: A system and method for controlling an internal combustion engine to reduce or eliminate formation of EGR condensate monitor current ambient and operating conditions to determine whether conditions are favorable for condensation of EGR gases, and control the engine accordingly to avoid condensation, preferably by increasing the intake manifold temperature. The intake manifold temperature may be increased by redirecting some or all of the EGR flow to avoid the EGR cooler. Alternatively, or in combination, some or all of the charge air may be redirected to bypass the charge air cooler and/or redirected from the outlet of the turbocharger compressor to the intake, effectively increasing the intake air temperature and resulting in a corresponding increase of the intake manifold temperature. Conditions favorable for condensation may be determined based on engine speed and load, ambient temperature, manifold pressure, scheduled or actual EGR flow rate and scheduled or actual air/fuel ratio.Type: ApplicationFiled: December 18, 2001Publication date: June 19, 2003Inventors: Phillip F. Rimnac, Ravishankar Ramamurthy, Sameer Bhargava
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Publication number: 20020189599Abstract: A method for controlling an engine during sensor degradation uses a remaining active sensor. The engine has an exhaust gas recirculation system utilizing pressure sensors upstream and downstream of an orifice. The downstream pressure sensor is coupled to the engine intake manifold and is also used for engine air-fuel ratio control.Type: ApplicationFiled: June 19, 2001Publication date: December 19, 2002Inventors: Allan J. Kotwicki, Freeman Carter Gates, Hossein Bina
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Patent number: 6401457Abstract: A system for estimating turbocharger compressor outlet temperature includes an engine controller responsive to any two of corrected turbocharger speed, corrected fresh mass air flow and turbocharger compressor pressure ratio (compressor outlet pressure/compressor inlet pressure) to compute compressor outlet temperature based on a corresponding compressor outlet temperature model.Type: GrantFiled: January 31, 2001Date of Patent: June 11, 2002Assignee: Cummins, Inc.Inventors: Yue Yun Wang, John M. Mulloy, Mark W. Pyclik
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Publication number: 20020053343Abstract: A state determining apparatus for an exhaust gas recirculation system is provided for appropriately determining the state of an exhaust gas recirculation system including an EGR passage. An exhaust gas recirculation system is arranged in an exhaust system of an internal combustion engine including an EGR passage for recirculating a portion of exhaust gases to an intake system in accordance with an operating state of the internal combustion engine. The state determining apparatus comprises a humidity sensor arranged in the EGR passage for detecting a humidity within the EGR passage, and an ECU for determining the state of the exhaust gas recirculation system based on a result detected by the humidity sensor.Type: ApplicationFiled: October 12, 2001Publication date: May 9, 2002Applicant: HONDA GIKEN KOGYO KABUSHIKI KAISHAInventors: Masahiro Sato, Yoshihisa Iwaki, Masaki Ueno, Shusuke Akazaki, Yasuyuki Miyahara
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Publication number: 20020046742Abstract: The invention provides an electronic control device for an internal combustion engine and a control method thereof in which more stable control is attained on the internal combustion engine in association with change in EGR amount due to change in atmospheric pressure.Type: ApplicationFiled: May 14, 2001Publication date: April 25, 2002Applicant: MITSUBISHI DENKI KABUSHIKI KAISHAInventor: Hideki Hagari
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Patent number: 6293267Abstract: An improved control methodology for an engine control valve, in which the valve is positioned in response to a commanded flow rate of the controlled medium. The method involves a valve characterization procedure in which the actual flow rate is measured for various combinations of valve position and pressure ratio across the valve, subject to a standard set of upstream pressure and temperature values. This results in a table of valve position in terms of pressure ratio and standard flow rate—that is, flow rate under the standard upstream pressure and temperature values. In operation, a controller addresses the table to obtain the desired valve position as a function of a determined pressure ratio across the valve, and a desired standard flow rate determined based on the commanded flow rate and the pressure and temperature of the controlled medium upstream of the valve, relative to the standard pressure and temperature values.Type: GrantFiled: March 23, 2000Date of Patent: September 25, 2001Assignee: Delphi Technologies, Inc.Inventors: James Craig Smith, Peter James Maloney
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Patent number: 6212881Abstract: An exhaust gas recirculation mechanism of an engine. Some of exhaust gas discharged from combustion chambers is recirculated to the combustion chambers through an EGR passage. An EGR valve is located in the EGR passage for adjusting the amount of recirculated exhaust gas. Foreign matter contained in exhaust gas in the EGR passage adheres to a valve shaft of the EGR valve that is exposed in the EGR passage. Normally, the opening amount of the EGR valve is controlled in accordance with the running state of the engine. If the opening amount of the EGR valve, which is determined based on the running state of the engine, is greater than a predetermined value, an ECU judges that the EGR ratio will fall within an acceptable range even if the EGR valve is fully opened from the current position. The ECU therefore forces the EGR valve to open fully. As a result, the foreign matter adhered to the valve shaft is removed without deteriorating the running condition of the engine.Type: GrantFiled: July 21, 1999Date of Patent: April 10, 2001Assignee: Toyota Jidosha Kabushiki KaishaInventors: Jun Takahashi, Hiroyuki Mizuno, Hironao Kishi