Abstract: 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.

Abstract: The invention relates to an exhaust gas recirculation device for an internal combustion engine, especially for a motor vehicle, comprising an exhaust gas recirculation line for recirculating exhaust gas, the line branching off from the exhaust line and running into an unburned gas line. The exhaust gas recirculation line includes a valve having a closing element which can be displaced between a closing position and an opening position by means of an actuator. One aim of the invention is to especially reliably prevent the closing element of the valve from sticking to the valve seat after the operation of the internal combustion engine. To this end, the closing element of the valve is placed in an idle position by means of the actuator, when the internal combustion engine is not in operation.

Abstract: A system is disclosed for diagnosing EGR flow rate operation in an internal combustion engine includes an intake manifold and an exhaust manifold coupled to the engine and an EGR conduit for recirculating exhaust gas from the exhaust manifold to the intake manifold. Means are provided for determining an EGR fraction corresponding to a fractional amount of recirculated exhaust gas in a total air charge supplied to the intake manifold. A control computer is configured to continually accumulate at least one EGR fraction error sum as a function of the EGR fraction and a desired EGR fraction, and to diagnose EGR flow rate operation as a function of the accumulated value of the at least one EGR fraction error sum.

Abstract: A method and a device for operating an internal combustion engine, in particular of a motor vehicle, which allow detecting a function of at least one actuating element in an exhaust branch without an additional sensory system. The internal combustion engine includes exhaust-gas recirculation via which exhaust gas is conveyed from the exhaust branch to an intake manifold in an activated state. The internal combustion engine includes at least one actuating element in the exhaust branch. In at least one operating state of the internal combustion engine, given activated exhaust-gas recirculation, a first intake-manifold pressure is ascertained in a first position of the at least one actuating element in the exhaust branch, and a second intake-manifold pressure in a second position of the at least one actuating element in the exhaust branch. The function of the at least one actuating element in the exhaust branch is monitored as a function of a difference between the first and the second intake-manifold pressures.

Abstract: An apparatus and method to detect abnormal combustion conditions for use as a feedback control of an EGR (Exhaust Gas Recirculation) controlled reciprocating engine using ionization signals is presented. The system receives a succession of ionization signals for successive cycles of a running engine and processes a plurality of related ionization signals for signal stability. The ionization signals are checked to determine if an abnormal combustion condition such as knock or misfire has occurred. The variation of an ionization signal that changes with respect to an engine parameter over a combustion event of the reciprocating engine is measured and a floating bounded space is associated with the ionization signal. An indication that the abnormal combustion condition has been detected is provided if a portion of the ionization signal is within the floating bounded space.

Abstract: The working fluid circuit of the present invention includes an exhaust gas passage through which exhaust gas under pressure flows from the internal combustion engine, a charge air passage, and a turbocharger. An exhaust gas recirculation passage extends between the exhaust gas passage and the charge air passage, but bypasses the turbocharger and provides a path for recirculating a predetermined amount of exhaust gas into the charge air passage in such a way that the exhaust gas and the charge air are mixed together. An intake passage provides intake air to the internal combustion engine. A single charge air cooler is operatively interconnected to and provides fluid communication between the charge air passage and the intake passage and acts to cool the mixed charge air and the recirculated exhaust gas prior to induction into the internal combustion engine through the intake passage.

Abstract: The invention relates to an exhaust gas recirculation device for an internal combustion engine, especially for a motor vehicle, comprising an exhaust gas recirculation line for recirculating exhaust gas, the line branching off from the exhaust line and running into an unburned gas line. The exhaust gas recirculation line includes a valve having a closing element which can be displaced between a closing position and an opening position by means of an actuator. One aim of the invention is to especially reliably prevent the closing element of the valve from sticking to the valve seat after the operation of the internal combustion engine. To this end, the closing element of the valve is placed in an idle position by means of the actuator, when the internal combustion engine is not in operation.

Abstract: An EGR-gas temperature estimation apparatus for an internal combustion engine which has an exhaust circulation pipe and an EGR-gas cooling apparatus. The estimation apparatus obtains the cooling efficiency &eegr;egr of the EGR-gas cooling apparatus from the temperature Tex of EGR gas at the inlet of the exhaust circulation pipe and the flow rate Gegr of the EGR gas, and obtains the temperature THW of engine cooling water, used as a coolant for the EGR-gas cooling apparatus. Subsequently, the estimation apparatus calculates the temperature Tegr of the EGR gas at the outlet of the exhaust circulation pipe by the expression Tegr=Tex−&eegr;egr·(Tex−THW). Since the cooling efficiency &eegr;egr greatly changes depending on the EGR-gas flow rate Gegr and the EGR-gas temperature Tex, the estimation apparatus can accurately estimate the cooling efficiency &eegr;egr, and therefore can accurately estimate the EGR-gas temperature Tegr.

Abstract: An internal combustion engine (1), especially of a motor vehicle, is described. The engine (1) is provided with a combustion chamber (4) into which fuel can be injected in a first operating mode during a compression phase and in a second operating mode during an induction phase. The engine (1) is provided with a control apparatus (18) for switching over between the operating modes. The engine (1) includes an exhaust-gas recirculation having an exhaust-gas recirculation valve (14). The engine (1) is switched by the control apparatus (18) into the first operating mode when the exhaust-gas recirculation valve (14) is jammed in the open state.

Abstract: The present invention relates to an EGR control unit and EGR control method for controlling an EGR adjusting apparatus, and it is an object of the invention to calculate an EGR rate at a low cost and to control an operation of the EGR apparatus with high accuracy. The EGR control unit is made up of temperature detecting devices detect in-passage temperature at least two of an intake passage, an atmospheric air introduction passage located on the upstream side of the intake passage and communicated with the atmosphere and an EGR passage, an actual EGR rate calculating device for calculating a rate of an exhaust gas to an intake gas in an internal combustion engine on the basis of information on temperatures detected by the temperature detecting devices, and an EGR controller for controlling the EGR adjusting device through the use of the actual EGR rate calculated by the actual EGR rate calculating device.

Abstract: The invention relates to the diagnosis of an exhaust gas recycling valve, whereby, on switching off the internal combustion engine, the throttle valve and the exhaust recycling valve are closed and a check is made of whether a compression is detectable in the cylinders of the internal combustion engine, by means of an engine speed check within a segment. Should an engine speed difference (Ndiff) be greater than a threshold value (Ndiff SW), then an incompletely closed exhaust gas recycling valve is recognized, assuming a complete closure of the throttle valve.

Abstract: A pressure sensor (40) is mounted in an internal combustion engine (1) for determining induction pipe pressure (P) in a connecting line (30) between the induction pipe (5) and the fuel pressure regulator (35). When checking the exhaust gas recirculation valve (20), induction pipe pressure (P) rises. Said change in pressure is safely and reliably recorded independently of actuation of other pneumatic consumers (vacuum power booster).

Abstract: A system for diagnosing an air handling mechanism of an internal combustion engine includes an air handling mechanism actuator, an air handling mechanism position sensor, a sensor associated with an engine operating condition separate from the air handling mechanism yet responsive to changes in the position of the mechanism actuator, and a control computer. The control computer is responsive to the position sensor signal and the engine operating condition sensor to diagnose faults/failure conditions associated with any of the air handling mechanism, the mechanism position sensor and the mechanism actuator. The air handling mechanism may be any of an EGR valve, a variable geometry turbocharger, a wastegate valve and an exhaust throttle, and the engine operating condition sensor may be associate with any of air intake pressure, air intake temperature, mass flow rate of intake air, exhaust gas pressure, EGR mass flow rate or turbocharger speed.

Abstract: An exhaust gas recirculation systems directs exhaust gasses from an exhaust manifold to an intake manifold of an internal combustion engine. The exhaust gasses travel from the exhaust manifold, first passing through a flow control valve and then through a measuring orifice before entering the intake manifold. Pressure upstream of the orifice is used, along with correction pressure downstream of the orifice, to measure and control exhaust gas flow. Further, manifold pressure is determined from downstream pressure and the used along with the measured exhaust gas flow to calculated a cylinder air charge amount.

Abstract: The working fluid circuit of the present invention includes an exhaust gas passage through which exhaust gas under pressure flows from the internal combustion engine, a charge air passage, and a turbocharger. An exhaust gas recirculation passage extends between the exhaust gas passage and the charge air passage, but bypasses the turbocharger and provides a path for recirculating a predetermined amount of exhaust gas into the charge air passage in such a way that the exhaust gas and the charge air are mixed together. An intake passage provides intake air to the internal combustion engine. A single charge air cooler is operatively interconnected to and provides fluid communication between the charge air passage and the intake passage and acts to cool the mixed charge air and the recirculated exhaust gas prior to induction into the internal combustion engine through the intake passage.

Abstract: A method and system for diagnosing a condition of an EGR valve used in an engine system. The EGR valve controls the portion exhaust gases produced by such engine system and fed back to an intake of such engine system. The engine system includes a NOx sensor for measuring NOx in such exhaust. The method includes: determining a time rate of change in NOx measured by the NOx sensor; comparing the determined time rate of change in the measured NOx with a predetermined expected time rate of change in measured NOx; and determining the condition of the EGR valve as a function of such comparison. The method also includes: determining from NOx measured by the NOx sensor and engine operating conditions indications of instances when samples of such measured NOx are greater than an expected maximum NOx level for such engine condition and less than an expected minimum NOx level for such engine condition; and determining the condition of the EGR valve as a function of a statistical analysis of such indications.

Abstract: The goal is to reliably diagnose and compensate for a change in the gas flow passing through an exhaust gas recirculation line. For this purpose, according to a first method, the mass flow passing through the exhaust gas recirculation line is derived as a function of the position and the flow characteristic of the exhaust gas recirculation valve, and, according to a second method, the mass flow is derived from the fresh-air mass flow in the induction pipe and from the induction pipe pressure. Then the difference is determined between the mass flows as ascertained in accordance with the two methods, and from the difference one or plurality of correcting quantities is generated for the mass flow that is derived as a function of the valve position and of the flow characteristic.

Abstract: 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.

Abstract: 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.

Abstract: A method for controlling a diesel engine exhaust gas recirculation system is described. In particular, a simplified diesel engine system is provided where presence of exhaust gas recirculation of flow is controlled via a two-position valve, while a quantity of exhaust gas recirculation is adjusted by varying the throttle valve. In this way, a reduced cost diesel exhaust gas recirculation system is achieved that provides the functionality of having variable amounts of exhaust gas recirculation.

Abstract: A method and system for controlling EGR rate of an internal combustion engine. The engine has an intake throttle for controlling mass flow to an intake of the engine and an EGR valve for controlling flow from the exhaust of the engine back to the intake of the engine along with air passing through the intake throttle. The method includes measuring a mass air flow passing to the intake throttle and a desired mass air flow. An error signal is produced representative of a difference between the measure mass air flow and the desired mass air flow. A pair of control signals is produced in response to such produced error signal. One of the pair of control signals is used to adjust the intake throttle to control mass air flow through such intake throttle. The other one of the pair of control signals is used to adjust EGR flow through the EGR valve. The pair of control signals operate the intake throttle and the EGR valve to drive the error signal towards a null.

Abstract: A control system for controlling an internal combustion engine having an exhaust gas recirculation mechanism consisting of an exhaust gas recirculation passage connected between the exhaust passage and the intake passage of the engine, and an exhaust gas recirculation valve provided in the recirculation passage for controlling an exhaust gas amount to be recirculated. Control parameter(s) of the engine are calculated according to operating conditions of the engine. An amount of change in the intake pressure between when opening the exhaust gas recirculation valve and when closing the exhaust gas recirculation valve, in the fuel-cut operation, is calculated. The abnormality of the exhaust gas recirculation mechanism is determined according to the amount of change in the intake pressure. The engine is controlled by using the control parameter suitable for a closed condition of the exhaust gas recirculation valve during a predetermined time period.

Abstract: The invention relates to the diagnosis of an exhaust gas recycling valve, whereby, on switching off the internal combustion engine, the throttle valve and the exhaust recycling valve are closed and a check is made of whether a compression is detectable in the cylinders of the internal combustion engine, by means of an engine speed check within a segment. Should an engine speed difference (Ndiff) be greater than a threshold value (Ndiff SW), then an incompletely closed exhaust gas recycling valve is recognized, assuming a complete closure of the throttle valve.

Abstract: A fuel supply control system for controlling a fuel amount to be supplied to an internal combustion engine having an exhaust gas recirculation mechanism comprising an exhaust gas recirculation passage connected between an intake pipe and an exhaust pipe, and an exhaust gas recirculation valve provided in the exhaust gas recirculation passage, is disclosed. The fuel amount to be supplied to the engine is corrected according to a pressure difference between an intake pressure detected when opening the exhaust gas recirculation valve and an intake pressure detected when closing the exhaust gas recirculation valve.

Abstract: A vehicle system controls a compression ignition internal combustion engine equipped with a supercharger system including a plurality of superchargers. The compression ignition internal combustion engine has an exhaust gas recirculation (EGR) system. The vehicle system determines a desired intake manifold supercharging state (tQac) and a desired EGR rate (Megr). The vehicle system includes control logics, each having a first input parameter and a second input parameter, for determining desired set points (Rvnt1 & Rvnt2) for the plurality of superchargers, respectively. The desired set points are used to control the plurality of superchargers, respectively. The vehicle system also includes control logic for determining the first input parameters in response to the desired intake manifold supercharging state. The vehicle system further includes control logic for determining the second input parameters in response to the desired EGR rate.

Abstract: An internal combustion engine (1), especially of a motor vehicle, is described. The engine (1) is provided with a combustion chamber (4) into which fuel can be injected in a first operating mode during a compression phase and in a second operating mode during an induction phase. The engine (1) is provided with a control apparatus (18) for switching over between the operating modes. The engine (1) includes an exhaust-gas recirculation having an exhaust-gas recirculation valve (14). The engine (1) is switched by the control apparatus (18) into the first operating mode when the exhaust-gas recirculation valve (14) is jammed in the open state.

Abstract: The present invention relates to an EGR control unit and EGR control method for controlling an EGR adjusting apparatus, and it is an object of the invention to calculate an EGR rate at a low cost and to control an operation of the EGR apparatus with high accuracy. The EGR control unit is made up of temperature detecting devices detect in-passage temperature at least two of an intake passage, an atmospheric air introduction passage located on the upstream side of the intake passage and communicated with the atmosphere and an EGR passage, an actual EGR rate calculating device for calculating a rate of an exhaust gas to an intake gas in an internal combustion engine on the basis of information on temperatures detected by the temperature detecting devices, and an EGR controller for controlling the EGR adjusting device through the use of the actual EGR rate calculated by the actual EGR rate calculating device.

Abstract: A system for diagnosing fault conditions associated with an air handling system for an internal combustion engine includes an air handling control mechanism responsive to a mechanism command to control fluid flow through an air handling system of an internal combustion engine. An engine controller is configured to compute predicted responses of a number of engine operating parameters each as a different function of the mechanism command, and to compute a corresponding number of correlation coefficients each as a function of one of the engine operating parameter signals and a corresponding one of the predicted responses. The controller is operable to diagnose a fault associated with the air handling control mechanism if at least some of the correlation coefficients are below a first threshold, and to diagnose a properly functioning air handling control mechanism if at least some of the correlation coefficients are above a second threshold.

Abstract: 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.

Abstract: A system and a method for recirculating a flow of exhaust gases. The system comprises a passage through which the exhaust gas flow passes, a valve movable in the passage between a generally open configuration and a generally closed configuration, an actuator operatively connected to the valve, and a fail-safe returning the valve to one of the generally open and generally closed configurations if the actuator is disabled. The generally open configuration of the valve substantially permits the exhaust gas flow to pass through the passage, and the generally closed configuration of the valve substantially prevents the exhaust gas flow from passing through the passage. The actuator includes a one-way driver and a release to move the valve between the generally open and generally closed configurations and to vary the exhaust gas flow though the passage. The method comprises energizing the actuator with a power supply, and moving the valve to a fail-safe position if the power supply fails.

Abstract: An EGR valve position control system includes an EGR valve manager responsive to an EGR valve command to drive an EGR valve actuator. The EGR valve manager is operable to schedule control gains as a function of valve actuation direction to provide for faster response during valve closing events. Valve closing events are also staged such that a large valve position step is followed by a steady ramp to the valve closed position to thereby prevent damage to the valve and/or valve seat. The EGR valve manager further includes a prioritized switching feature for strategically switching between closed and open loop control modes, and a forward gain adjustment feature responsive to battery voltage to maintain constant system DC gain under changing battery voltage conditions.

Abstract: A system and method for diagnosing a component failure in an internal combustion engine having an exhaust gas recirculation system and a variable geometry turbocharger for diverting exhaust gas from an engine exhaust to an engine intake include determining whether the engine is operating in boost control mode or EGR control mode, comparing EGR flow rate to a threshold corresponding to the current control mode, generating a fault if the EGR flow rate is outside an acceptable operating range based on the threshold for a first predetermined time period, and operating in boost control mode if the fault persists for a second predetermined time period. In one embodiment, the system and method determine that the engine is operating in the EGR control mode with the threshold corresponding to a minimum EGR flow rate and determine whether the EGR flow rate exceeds the threshold.

Abstract: An exhaust gas recirculation systems directs exhaust gasses from an exhaust manifold to an intake manifold of an internal combustion engine. The exhaust gasses travel from the exhaust manifold, first passing through a flow control valve and then through a measuring orifice before entering the intake manifold. Pressure upstream of the orifice is used, along with correction pressure downstream of the orifice, to measure and control exhaust gas flow. Further, manifold pressure is determined from downstream pressure and the used along with the measured exhaust gas flow to calculated a cylinder air charge amount.

Abstract: An EGR fault/failure determination system for an internal combustion engine is operable to monitor a number of EGR system operational parameters and diagnose various EGR-related fault and failure statuses therefrom. For example, the system is operable to determine a number of EGR system-related fault and failure conditions by monitoring measured and command EGR position signals to determine EGR valve controller functionality, to monitor response times between fully open and closed EGR valve positions by comparing measured response times to a calibratable response time value, and to monitor in-range EGR position failures associated with fully closed and fully opened EGR valve position values. The system further includes a Kalman filter-based fault/failure isolation feature operable to isolate and identify one or more sources of EGR valve-related faults/failures.

Abstract: The goal is to reliably diagnose and compensate for a change in the gas flow passing through an exhaust gas recirculation line. For this purpose, according to a first method, the mass flow passing through the exhaust gas recirculation line is derived as a function of the position and the flow characteristic of the exhaust gas recirculation valve, and, according to a second method, the mass flow is derived from the fresh-air mass flow in the induction pipe and from the induction pipe pressure. Then the difference is determined between the mass flows as ascertained in accordance with the two methods, and from the difference one or plurality of correcting quantities is generated for the mass flow that is derived as a function of the valve position and of the flow characteristic.

Abstract: Systems and methods for discriminating between an EGR temperature sensor fault and actual EGR temperatures which produce similar signals includes suppressing high voltage faults for a calibratible period of time after the engine is started. Alternatively, or in addition, a sensor fault is not indicated unless secondary indicators suggest that EGR temperature is sufficiently different from the EGR temperature corresponding to the sensor signal. Secondary indicators may include signals provided by various other engine and/or vehicle sensors such as an ambient air temperature sensor, engine coolant temperature sensor, oil temperature sensor, or the like.

Abstract: An internal combustion engine exhaust emission control system has a module for conveying exhaust gas from an engine exhaust system to an engine intake system. A valve selectively restricts the flow path. A pressure sensing passage communicates a pressure sensing port of a pressure sensor to the flow path. The pressure sensing passage comprises a tube having an end portion passing through a through-hole in a side wall of the flow path. In one embodiment, an open free end of the tube is disposed within the flow path in spaced relation to the side wall opposite an orifice that creates a pressure drop for obtaining a flow measurement using pressure sensed via the tube as one input. In another embodiment, the open free end of the tube is disposed flush with the side wall opposite a nozzle.

Abstract: An EGR valve position control system includes an EGR valve manager responsive to an EGR valve command to drive an EGR valve actuator. The EGR valve manager is operable to schedule control gains as a function of valve actuation direction to provide for faster response during valve closing events. Valve closing events are also staged such that a large valve position step is followed by a steady ramp to the valve closed position to thereby prevent damage to the valve and/or valve seat. The EGR valve manager further includes a prioritized switching feature for strategically switching between closed and open loop control modes, and a forward gain adjustment feature responsive to battery voltage to maintain constant system DC gain under changing battery voltage conditions.

Abstract: A control system and method for an EGR valve, particularly in a diesel engine. A processor processes data in feedback control of the position of the valve element to develop from the data a position control signal for setting the extent to which the valve is open. The processing includes processing data corresponding to actual position of the valve and data representing a desired position of the valve to develop a position error signal, processing data that defines actual EGR rate and data representing a desired EGR rate to develop a rate error signal, and processing the position error signal and the rate error signal to develop the position control signal. Emission control system event monitors flag potential error sources in their incipiency to afford opportunity for correction before mandatory logging occurs.

Abstract: Methods are disclosed for controlling an internal combustion engine in a vehicle which include detecting the value of a variable associated with an operating condition of the engine including the rotational speed and the load of the engine, determining a temperature value of a temperature-critical component associated with the engine, and controlling the thermal load of the engine based upon the predetermined temperature value by adding surplus fuel to the engine in a manner which gradually increases the supply of the surplus fuel based upon the value of the predetermined variable derived from the inherent thermal inertia in the temperature-critical component. Apparatus for controlling the engine in the vehicle is also disclosed.

Abstract: An improved test method for an EGR system reliably detects debilitating EGR system restrictions without significantly degrading combustion stability and exhaust emissions. The EGR valve test opening for diagnostic purposes is initialized at a relatively low value, which is progressively increased if the resulting change in intake manifold pressure fails to exceed a threshold based on the minimum expected change in intake manifold pressure for an EGR system that is regarded as functioning within acceptable limits. As soon as the measured pressure change exceeds the threshold, the EGR system is deemed to pass the restriction test, and the test method is terminated. If the EGR valve opening reaches a maximum value without the measured pressure exceeding the threshold, the EGR system is deemed to fail the restriction test, and a fault indication is generated.

Abstract: 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.

Abstract: A malfunction-detecting-device for an EGR stepping motor is provided wherein a circuit structure is furthermore simple and also more detailed malfunction information can be obtained by detecting the malfunction of the stepping motor during initialization drive of the stepping motor when an engine is just started. In order to determine that excitation coils of the EGR stepping motor have wire breaks, a driving-signal monitoring circuit is provide for monitoring a voltage surge as a monitoring signal generated by turning off a switching element for driving each of the excitation coils so as to cause self induction in the excitation coil. Malfunction detecting means of the EGR stepping motor is also provided for counting the number of monitoring inputs to the driving-signal monitoring circuit during initialization driving of the EGR stepping motor so as to determine the presence of wire breaks in the excitation coils when the number counted is less than the number of times the coils are driven.

Abstract: A method for diagnosing an exhaust-gas recirculation system of an internal combustion engine provides that the fuel quantity, which is needed for a desired mixture composition, is computed, at least approximately, in a control apparatus from at least stored data of the EGR system. The stored data can be in the form of a through-flow characteristic line. Thereafter, the fuel quantity is corrected by a control factor in dependence upon the mixture composition. The control factor is computed and stored when the EGR system is switched on and the control factor is computed and stored when the EGR system is switched off. The difference of these control factors is then formed and compared to pregiven values. A fault signal is outputted in the event of a deviation.

Abstract: A compression ignition type engine selectively switching between a first combustion where an amount of recirculated exhaust gas supplied in a combustion chamber (5) is greater than an amount of recirculated exhaust gas where the amount of production of soot peaks and a second combustion where the amount of recirculated exhaust gas supplied in the combustion chamber (5) is smaller than the amount of recirculated exhaust gas where the amount of production of soot peaks. A particulate filter (24) carrying a NOx absorbent (71) is arranged in the engine exhaust passage. When SOx should be released from the NOx absorbent (71) and there is leeway in the electrical energy stored in the battery (41), the first combustion is performed even when the second combustion should be performed and the drop in output power of the energy is made up by the output torque of an electric motor (37).

Abstract: The present invention involves a system and method of compensating sensor error of a differential pressure sensor on an exhaust gas recirculation passage for a calculation of a flow rate of recirculated exhaust gas into a vehicle engine. The method includes providing data representing default output of the differential pressure sensor based the coolant temperature of the engine and providing a predetermined threshold deviation of the default output. The method further includes determining the engine coolant temperature and an actual idle output of the sensor, when the engine is at an idle engine speed for a predetermined period of time, and calculating an actual error value of the sensor based on observing the actual idle output and engine coolant temperature. The method further includes utilizing the actual error of value of calculating the flow rate of the recirculated exhaust gas into the vehicle engine at off-idle conditions.

Abstract: When refreshing a catalyst (22) disposed in an exhaust line (20) during operation of a diesel engine (1), diesel engine control increases supercharging pressure by throttling nozzles of a turbocharger (25) so as to increase an amount of air that is charged into a combustion chamber (4) and then opens an exhaust gas recirculation valve (24) and holds it open until a exhaust gas recirculation ratio reaches a specified value. Subsequently, the diesel engine control increases an amount of fuel injection until a mean combustion chamber air-to-fuel ratio reaches a value near a stoichiometric air-to-fuel ratio so as to lower the oxygen concentration of exhaust gas, thereby causing the catalyst (22) to release NOx therefrom and purify the exhaust gas.

Abstract: A control system for controlling an internal combustion engine having an exhaust gas recirculation mechanism consisting of an exhaust gas recirculation passage connected between the exhaust passage and the intake passage of the engine, and an exhaust gas recirculation valve provided in the recirculation passage for controlling an exhaust gas amount to be recirculated. Control parameter(s) of the engine are calculated according to operating conditions of the engine. An amount of change in the intake pressure between when opening the exhaust gas recirculation valve and when closing the exhaust gas recirculation valve, in the fuel-cut operation, is calculated. The abnormality of the exhaust gas recirculation mechanism is determined according to the amount of change in the intake pressure. The engine is controlled by using the control parameter suitable for a closed condition of the exhaust gas recirculation valve during a predetermined time period.

Abstract: A malfunction-detecting-device for an EGR stepping motor is provided wherein a circuit structure is furthermore simple and also more detailed malfunction information can be obtained by detecting the malfunction of the stepping motor during initialization drive of the stepping motor when an engine is just started. In order to determine that excitation coils of the EGR stepping motor have wire breaks, a driving-signal monitoring circuit is provide for monitoring a voltage surge as a monitoring signal generated by turning off a switching element for driving each of the excitation coils so as to cause self induction in the excitation coil. Malfunction detecting means of the EGR stepping motor is also provided for counting the number of monitoring inputs to the driving-signal monitoring circuit during initialization driving of the EGR stepping motor so as to determine the presence of wire breaks in the excitation coils when the number counted is less than the number of times the coils are driven.

Abstract: A control system and method for an EGR valve, particularly in a diesel engine. A processor processes data in feedback control of the position of the valve element to develop from the data a position control signal for setting the extent to which the valve is open. The processing includes processing data corresponding to actual position of the valve and data representing a desired position of the valve to develop a position error signal, processing data that defines actual EGR rate and data representing a desired EGR rate to develop a rate error signal, and processing the position error signal and the rate error signal to develop the position control signal. Emission control system event monitors flag potential error sources in their incipiency to afford opportunity for correction before mandatory logging occurs.