Abstract: A control device for a compression ignition engine includes a controller configured to operate an engine body by compression ignition combustion when the engine body operates in a predetermined compression ignition range. When the engine body operates in a predetermined high load range of the compression ignition range, the controller maximizes a filling amount of the cylinder using a gas state adjustment system, and lowers an EGR ratio so that the air-fuel mixture in the cylinder is lean with an excess air ratio ? higher than 1 in a lower speed range, and maximizes the filling amount of the cylinder, and increases the EGR ratio so that the air-fuel mixture in the cylinder has the excess air ratio ? of 1 or lower in a higher speed range than the lower speed range.

Abstract: A malfunction diagnosis apparatus includes: a first temperature detector; a second temperature detector that is placed in a different location from where the first temperature detector is placed; a difference value calculation device calculates a difference value between a detection value from the first temperature detector and a detection value from the second temperature detector; a mapping device carries out mapping of the difference value and calculates a correction value using the frequency of the difference value; a malfunction diagnosis device diagnoses whether or not there is a malfunction in the first temperature detector and the second temperature detector; and a recovery device calculates, as a detection value of the first or second temperature detector judged to be malfunctioning, a value by adding the correction value to a detection value from the first or second temperature detector judged not to be malfunctioning.

Abstract: An object of the invention is to suppress a reduction in accuracy of abnormality diagnosis with an abnormality diagnosis device for an exhaust gas control apparatus that performs the abnormality diagnosis regarding the exhaust gas control apparatus by using the amount of NOx flowing into an SCR catalyst as a parameter.

Abstract: A system and method are disclosed for controlling the temperature of an aftertreatment system, the method including interpreting an aftertreatment indicating temperature, determining that an engine fueling requirement is zero, and disengaging the engine from a transmission in response to the aftertreatment indicating temperature falling below a first threshold value and in response to the engine fueling requirement being zero, where the engine and the transmission comprise a portion of a vehicle powertrain. Alternatively, the method may include interpreting an aftertreatment indicating temperature, determining that an engine fueling requirement is zero, and performing a reduced air flow operation through the engine in response to the aftertreatment indicating temperature falling below a first threshold value and in response to the engine fueling requirement being zero.

Abstract: An abnormality diagnosis apparatus includes: an exhaust gas purification apparatus arranged in an exhaust passage of an internal combustion engine and including a selective catalytic reduction catalyst; a supply apparatus supplying an additive such as ammonia to the exhaust gas purification apparatus; an EGR apparatus recirculating a part of exhaust gas from the exhaust passage at a downstream side of a position of supplying the additive to an intake passage; calculating means for calculating a NOx inflow amount into the exhaust gas purification apparatus using a parameter indicating an operating state of the internal combustion engine; diagnosing means for diagnosing an abnormality in the exhaust gas purification apparatus using the calculated NOx inflow amount as a parameter; and correcting means for, when a part of the exhaust gas is recirculated, increasingly correcting the calculated NOx inflow amount in accordance with an amount of the additive to be recirculated together with exhaust gas.

Abstract: A method of operating an Exhaust Gas Recirculation (EGR) valve of an engine is provided. The method includes monitoring an operating condition of the engine based at least on a speed of the engine and a load of the engine. The method also includes determining an amount of Carbon Monoxide (CO) in an exhaust from the engine and comparing the amount of CO with a threshold CO value. The method further includes adjusting open loop parameters of the EGR valve based on the comparison during a predetermined operating condition for the engine. The EGR valve is controlled based on the open loop parameters during switching between a closed loop control and an open loop control of the EGR valve.

Abstract: A control device and method for the air system of a diesel engine is disclosed. The feature of the diesel engine is characterized by transfer function. During the control process, a decoupling transfer function is computed according to the transfer function and the steady working parameters of the diesel engine. By the decoupling transfer function acting on the processed state parameters of the air system, driving signals for controlling the exhaust gas recirculation system and the turbocharge system can be individually generated from one another, in order to realize decoupling of them.

Abstract: Systems and methods are provided for recycling internal combustion engine feedgas exhaust emissions during cold-start conditions. By adjusting a restriction valve provided in an exhaust passage upstream of a catalytic converter, an amount of engine exhaust flowing through the catalytic converter prior to the catalytic converter reaching its operational temperature may be reduced.

Abstract: A flow rate controller of an internal combustion engine includes a flow rate change section configured by including an EGR valve, a bypass valve, and a diesel throttle, as the flow rate change section capable of changing at least one of a flow rate of exhaust gas that is recirculated to an intake system from an exhaust system of an internal combustion engine via an EGR passage and a flow rate of fresh air that flows into the internal combustion engine. In addition, an ECU is included to realize: an arrival position determining section for determining an arrival position of condensed water in the EGR passage that is moved by the EGR at least either at the time of acceleration or at the time of deceleration of the internal combustion engine; and a control section for controlling the flow rate change section on the basis of the arrival position determined by the arrival position determining section.

Abstract: EGR gas quantity information, which indicates a quantity of the EGR gas flowing into a cylinder of an internal combustion engine, is obtained by an ECU. A combustion stop delay control operation, which delays execution of a combustion stop control operation, is executed by the ECU when the quantity of the EGR gas flowing into the cylinder is larger than a normal combustion determination threshold value. When the quantity of the EGR gas flowing into the cylinder becomes equal to or smaller than the normal combustion determination threshold value, the combustion stop control operation is enabled by the ECU.

Abstract: An exhaust gas recirculation control device of an engine is provided. The device includes: an exhaust turbocharger having a turbine disposed in an exhaust passage and a compressor disposed in an intake passage; an intercooler disposed in the intake passage downstream of the compressor; a low-pressure EGR passage connecting the exhaust passage downstream of the turbine to the intake passage upstream of the compressor; a low-pressure EGR valve disposed in the low-pressure EGR passage and for changing a cross-sectional area thereof; a high-pressure EGR passage connecting the exhaust passage upstream of the turbine to the intake passage downstream of the intercooler; a high-pressure EGR valve disposed in the high-pressure EGR passage and for changing a cross-sectional area thereof; a valve control device for controlling openings of the low-pressure and high-pressure EGR valves; and a gear range detector for detecting a gear range of a transmission.

Abstract: While an engine is an idling state and an EGR opening degree is increased stepwise from a specified opening degree, a variation in engine speed (a standard deviation in engine speed) is repeatedly computed. After that, a specified step amount is successively reduced from the EGR opening degree and the variation in engine speed is successively computed until the EGR opening degree becomes less than or equal to a specified value. Then, a maximum value of the EGR opening degrees where the variation in engine speed becomes minimum is learned as the full-close position.

Abstract: A method for reducing a nitrogen oxide emission in a diesel engine. The method can include taking at least one exhaust gas of an in engine combustion in a combustion chamber and: segmenting a first portion of exhaust gas enters as an internal exhaust gas recirculation from the combustion chamber of the diesel engine via an outlet valve associated with the combustion chamber, and is recirculated, via the outlet valve, from the subsequent exhaust gas tract, into the combustion chamber of the diesel engine; segmenting a second portion of exhaust gas remains in the combustion chamber and is not expelled; and segmenting a third portion of exhaust gas is recirculated as external exhaust gas recirculation via an exhaust gas recirculation valve into the combustion chamber.

Abstract: The present disclosure relates to a method for controlling an exhaust gas recirculation apparatus for heavy construction equipment, and more particularly, to a method for controlling an exhaust gas recirculation apparatus for heavy construction equipment, capable of controlling exhaust gas at an appropriate pressure at an appropriate step when making exhaust gas discharged from an engine flow into the engine together with fresh gas.

Abstract: Systems and methods are provided for adjusting an engine powertrain component responsive to ambient humidity, the ambient humidity based on vehicle position in a region, clock time ambient temperature, and historical humidity data for that region for a current time of year. This may be accomplished without relying on a costly, and often, temperamental physical humidity sensor. Training modules and cloud updates may further increase the accuracy of the virtual humidity sensor of the present disclosure.

Abstract: Methods and systems are provided for improving accuracy of delta pressure over valve (DPOV) based EGR flow measurement during low valve lift conditions by learning errors in EGR valve lift and/or EGR valve flow transfer function.

Abstract: This disclosure provides a system and method for controlling internal combustion engine system to reduce operation variations among plural engines. The system and method utilizes single-input-single-output (SISO) control in which a single operating parameter lever is selected from among exhaust gas recirculation (EGR) fraction and charge air mass flow (MCF), and a stored reference value associated with the selected lever is adjusted for an operating point in accordance with a difference between a measured emissions characteristic and a pre-calibrated reference value of the emissions characteristic for that operating point. Adjusting the selected operating parameter lever towards the theoretical pre-calibrated reference value of the operating parameter lever for each of plural operating points can reduce engine-to-engine variations in engine out emissions.

Abstract: When the difference by which pressure in an engine exhaust manifold exceeds pressure in an engine intake manifold becomes less than a selected difference while an intake valve operating mechanism is closing cylinder intake valves at a selected time in the engine cycle, while an EGR system is conveying the engine exhaust component of an air/exhaust mixture from an exhaust system to an intake system, and a certain quantity of NOx is present in engine exhaust entering the exhaust manifold, the quantity of NOx present in engine exhaust entering the exhaust manifold is reduced below that certain quantity by causing the intake valve operating mechanism to close the cylinder intake valves earlier in the engine cycle than the selected time.

Abstract: A method and related apparatuses and systems for operating an engine that provides a high level of NOX to regenerate particulate matter deposited on a particulate filter. The method includes producing NOX in response to a NOX excess capacity value of a NOX reduction device. The method optionally includes determining that particulate matter exceeds an enhanced passive regeneration threshold amount before providing a high level of NOX. The method optionally includes producing a higher particulate emissions output value to warm the engine exhaust to bring an aftertreatment catalyst to an optimal operating temperature. The method can be implemented with a closed loop feedback controller, which may be configured to reduce particulate matter variation.

Abstract: A method and system for providing a suitable engine torque response during a transient condition is presented. In one example, when a desired inlet manifold pressure is greater than a throttle inlet pressure of a first throttle, a second throttle positioned upstream from the first throttle is opened to increase the throttle inlet pressure. The method may provide an appropriate torque response while minimizing impact on fuel economy.

Abstract: A six-stroke engine system including an engine with a combustion chamber including an exhaust valve that expels exhaust gasses during an exhaust stroke, and a blowdown exhaust valve that expels blowdown exhaust gasses during recompression. An intake line directs air into the combustion chamber, and an exhaust line directs exhaust gasses from combustion chamber. A blowdown exhaust line directs blowdown exhaust gasses out of the combustion chamber and into the intake line. The blowdown exhaust gasses are expelled through the blowdown exhaust valve during recompression, and exhaust gasses are expelled through the exhaust valve during the exhaust stroke.

Abstract: A method for controlling a vehicle's exhaust gas recirculation system. The method controls the exhaust gas recirculation system in a manner that is suitable for a pedal tip-out transition while also being optimized for normal operating situations.

Abstract: A system and method for measuring an EGR flow rate for an engine having an EGR valve with a selectable EGR valve position and a venturi sensor situated to take a differential pressure measurement relative to recirculated exhaust gas includes determining an EGR valve effective area based on the EGR valve position, determining a weighting factor based on the effective area, calculating a first EGR flow estimate based on the effective area, and calculating a second EGR flow estimate based on the differential pressure measurement of the venturi sensor. A final EGR flow rate is determined based on the weighting factor, the first EGR flow estimate, and the second EGR flow estimate.

Abstract: A method of calibration of at least one fuel injector for a fuel burner in an exhaust gas treatment system for an internal combustion engine is provided. The method is adapted for an exhaust gas system having the fuel burner mounted upstream of a diesel particle filter (DPF). The method of calibration is performed during an idle speed of the combustion engine, this to assure a constant temperature of the burner during the calibration. Hence, the method is started when a first steady tempera tore is registered in the fuel burner, wherein the at least one fuel injector, is operated with a first pulse width. A first temperature of an exhaust gas is registered directly downstream of the fuel burner. After this first temperature is registered, the pulse width, of the fuel injector changed into a second pulse width, which is different from the first pulse width.

Abstract: Methods and systems are provided for estimating a positive crankcase ventilation (PCV) flow based on outputs of an intake manifold oxygen sensor. For example, during engine operation when exhaust gas recirculation (EGR) and fuel canister purge are disabled, PCV flow may be estimated based on a difference between a first output of the sensor with boost enabled and a second output of the sensor with boost disabled. Then, during subsequent operation wherein EGR is enabled, PCV flow is enabled, and purge is disabled, a third output of the sensor may be adjusted based on the estimated PCV flow.

Abstract: There is provided an internal combustion engine control apparatus that can more accurately calculate a volume efficiency correction coefficient and can more accurately estimate the amount of air that flows into a cylinder and the external exhaust gas recirculation amount. In an internal combustion engine provided with an exhaust gas recirculation apparatus including an exhaust gas recirculation valve and an exhaust gas recirculation path, based on a cylinder flow rate, an exhaust gas recirculation amount, an inner-intake-pipe density, and an inner-intake-pipe density changing amount, a volume efficiency correction coefficient, as a volume efficiency corresponding value, is calculated; then, by use of the calculated volume efficiency correction coefficient, a cylinder intake air amount and a recirculation amount of exhaust gas that is taken into the cylinder are calculated.

Abstract: Disclosed is a control device for an internal combustion engine that is used with an internal combustion engine having an EGR catalyst and an EGR valve in an EGR path for connecting an exhaust path to an intake path, and capable of preventing the purification performance of the EGR catalyst from being degraded during EGR stoppage and purifying exhaust gas in a preferred manner upon EGR resumption. When EGR is stopped with the EGR valve closed, the control device judges whether an EGR path air-fuel ratio is richer than a threshold value. If the EGR path air-fuel ratio is judged to be richer than the threshold value, the control device sets a target air-fuel ratio for the internal combustion engine to be leaner than a stoichiometric air-fuel ratio.

Abstract: A control apparatus judges an abnormality of an internal combustion engine. The engine has an external EGR apparatus, including an exhaust gas recirculation passage that connects an exhaust passage with an intake passage, and an EGR valve that can increase and decrease an outside EGR flow quantity that flows back into the intake passage from said exhaust passage through the exhaust gas recirculation passage by being adjusted in its opening angle. The control apparatus acquires an output value of the engine and determines occurrence of abnormality in the external EGR apparatus according to a predetermined criterion based on a difference between an output of the engine in which a first EGR flow quantity is flown back and an output of the engine in which a second EGR flow quantity is flown back.

Abstract: A control system for an internal combustion engine having a throttle valve disposed in an intake passage of the engine. A target intake air amount of the engine is calculated, and an intake pressure of the engine is estimated. A wide-open intake air amount is calculated according to the engine rotational speed, and a theoretical intake air amount is calculated according to the wide-open intake air amount and the intake pressure. The wide-open intake air amount is an intake air amount corresponding to a state where the throttle valve is fully opened, and the theoretical intake air amount is an intake air amount corresponding to a state where no exhaust gas of the engine is recirculated to a combustion chamber of the engine. further, an exhaust gas recirculation ratio is calculated using the theoretical intake air amount and the target intake air amount, and a target output torque of the engine is calculated using the target intake air amount and the exhaust gas recirculation ratio.

Abstract: The invention relates to a method and an arrangement for operating an internal combustion engine. In the method a first distribution of values for at least one variable is used, the variable describing a physical property of the internal combustion engine, and over a second time period values for this variable are recorded and classified, such that a second distribution is determined. The first distribution is then compared with the second distribution such that the behavior of the internal combustion engine can be adapted on the basis thereof.

Abstract: A method of controlling an exhaust gas recirculation system of an internal combustion engine is disclosed. The engine includes a compressor, an intake manifold, an after-treatment system, a low pressure EGR system and a high pressure EGR system. The method temporarily adjusts a low pressure EGR ratio, keeping constant a total EGR rate, after verifying at least one among compressor parameters, after-treatment system parameters or intake manifold parameter.

Abstract: A system includes a reciprocating internal combustion engine with one or more reaction zones configured to receive a charge flow that is configured to react within the one or more reaction zones, thereby forming an exhaust gas flow, and a controller. The charge flow includes an oxidant flow, a fuel flow, and a recirculated portion of the exhaust gas flow. The controller is configured to control a ratio of the recirculated portion of the exhaust gas flow to a fuel mixture. The controller controls the ratio based at least in part on a first temperature, a second temperature of the charge flow, and a third temperature of the recirculated portion of the exhaust gas flow. The fuel mixture includes the oxidant flow and the fuel flow. The first temperature includes one or any combination of a sensed temperature of the oxidant flow, the fuel flow, or the fuel mixture.

Abstract: Methods and systems are provided for accurately learning the zero point of an intake gas oxygen sensor during selected idling conditions. The learned zero point is used to infer EGR flow and accordingly adjust EGR valve control. In addition, EGR valve leakage is diagnosed based on the zero point learned during an idle adaptation relative to a zero point learned during a DFSO adaptation.

Abstract: A method and apparatus for controlling a boost pressure of a turbocharger is provided. The turbocharger includes a waste gate valve and a waste gate actuator. When the internal combustion engine operates under cold temperature conditions, a steady state temperature of the waste gate actuator is determined and a corrected temperature of the waste gate actuator is estimated as a function of the thermal convection between ambient air and the waste gate actuator. A corrected value of the duty cycle of a pulse width modulated signal is estimated as a function of said corrected temperature and the duty cycle corrected value is used to control the boost pressure of the turbocharger.

Abstract: Methods and systems are provided for accurately learning the zero point of an intake gas oxygen sensor during selected engine no-fueling conditions. The learned zero point is used to infer EGR flow and accordingly adjust EGR valve control. In addition, EGR valve leakage is diagnosed based on the zero point learned during a DFSO adaptation relative to a zero point learned during an idle adaptation.

Abstract: A fuel admission control unit controls a diesel engine and ensures compatibility between exhaust gas performance and engine speed response performance by considering residual oxygen in EGR gas. The control unit includes an estimation excess air ratio ?s computing unit that is an arithmetic section to compute an estimation excess air ratio ?s, from the quantity of the fuel injected by a fuel injection valve into a cylinder, the intake air flow rate, and the flow rate of the residual oxygen in the EGR gas that returns back into the intake air system. The control unit also includes a fuel admission control unit that controls the fuel flow rate under hard acceleration, based on the estimation excess air ratio ?s that is computed by the estimation excess air ratio ?s computing unit.

Abstract: Methods and systems for metering at least one EGR valve to a position determined to pass a desired EGR flow for a given set of engine characteristics. The methods include determining the EGR valve position based on pipe flow characteristics, or determining the EGR valve position based on pipe flow characteristics when differential pressure across the EGR valve is less than a pressure threshold.

Abstract: An internal combustion engine is configured to utilize a reactivity controlled compression ignition process and an exhaust gas recirculation (“EGR”) system. The EGR system directs a portion of the exhaust gasses from the exhaust system to the air intake system. The engine system is adapted to introduce a first fuel charge having a first reactivity to a combustion chamber at a first time during the intake-compression cycle of the engine. The engine system is also adapted to introduce a second fuel charge having a second reactivity at a second time during the intake-compression cycle to generate stratified regions of different reactivity in the combustion chamber. A controller operatively associated with the engine can monitor one or more operating parameters and can adjust either the EGR system and/or the second introduction of the second fuel charge based in part upon the operating parameter.

Abstract: The present invention makes it possible to accurately determine an EGR rate from an in-cylinder pressure. An EGR rate determination method for an internal combustion engine according to the present invention, a combustion period is calculated by using in-cylinder pressure data measured by an in-cylinder pressure sensor. An in-cylinder flame velocity is then calculated from the combustion period. Next, in accordance with prepared data indicative of the influence of an engine speed on the flame velocity, a portion of the flame velocity calculated from the combustion period that is affected by the engine speed is eliminated. Eventually, a current EGR rate is determined from the flame velocity from which the portion affected by the engine speed is eliminated.

Abstract: A working gas circulation type engine includes a combustion chamber in which a working gas having a ratio of specific heats higher than that of air can be expanded by combustion of a fuel, a circulation path capable of circulating a gas containing the working gas from a gas exhaust side to a gas suction side of the combustion chamber and supplying the gas containing the working gas to the combustion chamber again, and a control device that changes a control parameter for controlling the combustion of the fuel based on a ratio of specific heats of the gas circulating in the circulation path. Therefore, there can be provided the working gas circulation type engine capable of obtaining a stable output.

Abstract: A compressor assembly pressurizes an airflow that is received from the ambient for delivery to an internal combustion engine having a cylinder block section and a cylinder head section. The cylinder head section is configured to supply an air-fuel mixture to the cylinder for combustion therein and exhaust post-combustion gases therefrom. The compressor assembly includes a compressor cover configured to receive the airflow from the ambient and a compressor wheel disposed inside the compressor cover and configured to pressurize the airflow. The compressor assembly also includes an exhaust gas recirculation (EGR) valve that is incorporated into the compressor cover and is in fluid communication with each of the cylinder head section and the compressor wheel. The EGR valve is configured to control delivery of the exhaust post-combustion gases from the cylinder head into the compressor cover. An internal combustion engine employing such a compressor assembly is also disclosed.

Abstract: Methods and systems are provided for improving accuracy of delta pressure over valve (DPOV) based EGR flow measurement during low valve lift conditions by learning errors in EGR valve lift and/or EGR valve flow transfer function.

Abstract: When a constant driving voltage is applied to a motor driving an EGR valve so that the EGR opening degree is varied, an angular speed of the EGR valve becomes minimal at a position where the driving torque of the EGR valve becomes maximal. In view of this, while an opening degree of the EGR valve is varied with a constant driving voltage applied to the motor, the EGR opening degree where the angular speed becomes minimal is learned as a full-close position.

Abstract: Exhaust gas recirculation (EGR) systems and methods are provided. In one embodiment, a method for controlling an engine includes providing a first EGR gas flow to an intake manifold of the engine by closing a first EGR valve or a second EGR valve and at least partially opening the other of the first EGR valve and the second EGR valve, wherein the first and second EGR valves are respectively positioned in first and second EGR passages respectively coupled between first and second donor cylinder groups and an intake manifold, and providing a second EGR gas flow that is higher than the first EGR gas flow to the intake manifold by fully opening the first EGR valve or the second EGR valve and at least partially opening the other of the first EGR valve and the second EGR valve.

Abstract: A control system for an internal combustion engine where when the engine is decelerating the amount of intake air supplied to a combustion chamber is controlled. A target auxiliary intake air amount SAIRCMD necessary for preventing misfiring of the engine by supplying only an auxiliary intake air amount to a combustion chamber and a target intake air amount GAIRCMD which is a target value of the amount of intake air supplied to the combustion chamber are calculated according to the state NE, AP of the engine. When the engine is decelerating, and misfires, misfire avoidance control is executed controlling an auxiliary intake air amount control valve to be more opened such that the auxiliary intake air amount becomes the target auxiliary intake air amount SAIRCMD and a throttle valve to be more closed such that the amount of intake air supplied to the combustion chamber becomes the target intake air amount GAIRCMD.

Abstract: A flow rate controller of an internal combustion engine includes a flow rate change section configured by including an EGR valve, a bypass valve, and a diesel throttle, as the flow rate change section capable of changing at least one of a flow rate of exhaust gas that is recirculated to an intake system from an exhaust system of an internal combustion engine via an EGR passage and a flow rate of fresh air that flows into the internal combustion engine. In addition, an ECU is included to realize: an arrival position determining section for determining an arrival position of condensed water in the EGR passage that is moved by the EGR at least either at the time of acceleration or at the time of deceleration of the internal combustion engine; and a control section for controlling the flow rate change section on the basis of the arrival position determined by the arrival position determining section.

Abstract: An exhaust gas feed device for an internal combustion engine includes an exhaust gas recirculation duct comprising an end, an outlet, and an outflow cross-section. An air intake duct opens into the exhaust gas recirculation duct. A flow-guiding element is arranged in and at the end of the exhaust gas recirculation duct. An exhaust gas recirculation valve comprises a regulator body. The regulator body is configured to control the outflow cross-section. A valve seat is arranged at the outlet at the end of the exhaust gas recirculation duct in which the flow-guiding element is arranged. The valve seat is configured to limit the outflow cross-section of the exhaust gas recirculation duct.

Abstract: An intake air quantity information determining arrangement senses or computes one of an intake air quantity and a torque of an internal combustion engine as intake air quantity information. A misfire-avoidance control arrangement executes a misfire-avoidance control operation, which avoids misfire by controlling a throttle opening degree of a throttle valve such that a value of the intake air quantity information does not decrease below a normal combustion threshold value.

Abstract: A method for adjusting an exhaust heat recovery valve is presented. In one embodiment, the method may control an amount of boost provided by a turbocharger to an engine.

Abstract: Various methods and systems are provided for diagnosing an engine component condition in an exhaust gas recirculation system. In one example, a method includes selectively routing exhaust from a subset of engine cylinders to an exhaust passage via a first valve and to an intake passage via a second valve, and obtaining one or more of a pressure or temperature from the subset of engine cylinders. The method further includes indicating an engine component condition based on the one or more of the pressure or temperature.