Abstract: Methods and systems are provided for a boosted engine having a split exhaust system. In one example, a method comprises directing exhaust from a first cylinder group to one or more of a pre-compressor location, a post-compressor location, and an exhaust turbine, and directing exhaust from a second cylinder group to one or more of the pre-compressor location, and the exhaust turbine. Engine efficiency and knock control may be enhanced by directing exhaust gases to different locations based on engine operating conditions.

Abstract: A natural gas system for a vehicle includes a fuel pod, a conduit defining a flow path, a fuel control module, and an accumulator. The fuel pod includes a fuel tank configured to store natural gas. The conduit includes a first end coupled to the fuel pod and a second end configured to be coupled to an engine. The fuel control module is disposed along the flow path and configured to regulate a flow of natural gas to the engine. The accumulator is disposed along the flow path downstream of the fuel control module. The accumulator is configured to buffer variations in the flow of natural gas such that the engine receives a consistent flow of natural gas.

Abstract: Systems and methods for improving combustion in a highly exhaust gas diluted engine are disclosed. The methods and systems may be provided in an engine that includes independent control of cylinder valves with respect to other cylinder valves.

Abstract: If operation mode of an engine is transitioned from natural aspiration lean-burn operation mode to supercharged lean-burn operation mode, an engine control portion temporarily changes an air-fuel ratio from a lean air-fuel ratio to a stoichiometric air-fuel ratio or a rich air-fuel ratio. When the air-fuel ratio is changed from the lean air-fuel ratio to the stoichiometric air-fuel ratio or the rich air-fuel ratio by the engine control portion, a transmission control portion switches a gear ratio of the automatic transmission to a gear ratio that provides an engine rotational speed at which the engine output becomes equal to an engine output before the air-fuel ratio is changed and also at which an intake pipe pressure becomes equal to or closest to an intake pipe pressure before the air-fuel ratio is changed.

Abstract: An improved apparatus for reducing friction in an EGR driver may include a space member mounted on a stem and having a side provided with a plurality of depressed portions to reduce a contact area with an inner side of a valve, such that the friction generated by a contact of the stem with a stem guide when the stem provided inside the valve vertically moves is reduced.

Abstract: A housing has an housing body. An inner pipe is accommodated in the housing body. The inner pipe defines an inner passage internally. The inner pipe defines an annular passage externally with the housing body. The inner pipe has through holes 68 communicating the inner passage with the annular passage. The housing internally defines an EGR channel communicating with the annular passage. The EGR channel accommodates a diffusing device 60 partitioning the EGR channel.

Abstract: An EGR device includes a housing and a valve. The housing has an outer pipe and an inner structure. The inner structure is located inside the outer pipe to define an annular passage externally with the outer pipe. The inner structure defines an inner passage internally. The inner structure has apertures. The valve is in a tubular shape and is located inside the inner structure. The valve is slidable in an axial direction to communicate the annular passage with the inner passage through the apertures and to block the inner passage from the annular passage.

Abstract: Methods and systems are provided for engine dilution control via direct injection of water from a reservoir. In one example, a method may include during select conditions, direct injecting fluid from a reservoir into an EGR cooler. This approach can be used to supplement EGR flow during situations that decrease EGR flow.

Abstract: In an engine unit including a combustion unit and an exhaust fluid recirculation apparatus where unburnt fuel is provided to an exhaust flow treatment apparatus for combustion, it may be desirable to prevent unburnt fuel from entering the exhaust fluid recirculation apparatus. A method of controlling operation of an engine unit includes confirming that a valve of the exhaust flow recirculation apparatus is closed, and overriding a control signal for controlling the valve in order to ensure that the valve remains closed before injecting fuel upstream of the valve for combustion in the exhaust fluid treatment apparatus.

Abstract: An exhaust gas recirculation device for a motor vehicle is disclosed with includes an unburnt gas line for guiding an unburnt gas flow and at least one exhaust gas feed line for supplying exhaust gas into the unburnt gas line. At least two discharge openings offset relative to each other in the circumferential direction of the unburnt gas line are provided in the unburnt gas line, by way of which the exhaust gas can be or is supplied to the unburnt gas line.

Abstract: The invention relates to a method for regenerating nitrogen oxide storage catalytic converters and to a correspondingly adapted exhaust-gas purification system for lean-burn engines. In particular, the present invention relates to the regeneration of nitrogen oxide storage catalytic converters during special driving situations of the vehicle.

Abstract: Methods and systems are provided for estimating an impact of PCV hydrocarbons on an output of an intake oxygen sensor. In one example, a method may include disabling EGR flow when the impact of PCV hydrocarbons on the output of the intake oxygen sensor is above a threshold. The impact of the PCV hydrocarbons on the output of the intake oxygen sensor may be based on a difference between the output of the intake oxygen sensor and a DPOV sensor when EGR is flow and a difference between the output of the intake oxygen sensor and expected blow-by when EGR is not flowing.

Abstract: Various systems and method for controlling exhaust gas recirculation (EGR) in an internal combustion engine are provided. In one embodiment, a method includes injecting fuel to a subset of cylinders that includes less than all cylinders of a first cylinder group to obtain a target EGR rate. The first cylinder group provides exhaust gas through an exhaust gas recirculation (EGR) passage structure fluidly coupled between the first cylinder group and an intake passage structure. The method further includes injecting fuel to at least one cylinder of a second cylinder group. The second cylinder group provides substantially no exhaust gas through the EGR passage structure.

Abstract: In an exhaust system for an internal combustion engine, an output member is configured to transmit power generated by a motor to a valving element via a valve stem. An output shaft is disposed on a rotation central axis of an output gear and coupled with the output gear to be rotatable integrally therewith. A follower is disposed eccentrically relative to a rotation central axis of the output shaft and connected to the output shaft to be rotatable integrally therewith. A first accommodating chamber accommodates at least the valve stem and the follower. A second accommodating chamber accommodates at least the motor and the output gear. A housing includes a housing wall that divides the first chamber from the second chamber. The housing wall includes a first bearing slidably supporting the output shaft in its rotation direction, and a cylindrical first bearing holder holding outer periphery of the first bearing.

Abstract: An object of the present invention is to restrain the emission amount of unburned fuel components while restraining the consumption of fuel with relatively high ignitability in a multi-fuel internal combustion engine. The present invention resides in such a fuel supply control system for a multi-fuel internal combustion engine that a first fuel with relatively high ignitability and a second fuel with relatively low ignitability are used as fuels and the first fuel is used as an ignition source to mixedly combust the first fuel and the second fuel, wherein a supply amount Qd of the first fuel is adjusted on the basis of a difference ?RH between a first heat generation rate RHd which is a heat generation rate given when assuming that only the first fuel is combusted and an actual heat generation rate RHa which is a heat generation rate given when the fuels are actually combusted (S105 to 107, S109).

Abstract: Various methods and systems are provided for blocking backflow of exhaust through an exhaust gas recirculation system. In one embodiment, a method comprises flowing exhaust gas through an exhaust gas recirculation (EGR) passage in a first direction from at least a first cylinder group of an engine to an intake manifold of the engine, the exhaust gas flowing in the first direction through a filter arranged in the EGR passage prior to reaching the intake manifold, and blocking flow of gas through the filter in a second, opposite direction with a mechanical one-way valve positioned in the EGR passage between the filter and the intake manifold.

Abstract: Various methods and systems may be used to provide recirculated engine exhaust to an engine of a hybrid powertrain. It is assumed that the engine is equipped with a dedicated EGR loop. At least one cylinder is operated as a dedicated exhaust gas recirculation (EGR) cylinder, such that all exhaust of that cylinder is recirculated to the fresh air intake of the engine via the EGR loop. One or more cylinders are operated as main cylinders, such that exhaust from those cylinders exits the engine to the atmosphere. The engine itself is operable for at least part of its operation in a decoupled mode in which the dedicated EGR cylinder is mechanically decoupled from the engine crankshaft. During this decoupled mode, the dedicated EGR cylinder powers a generator. The main cylinders are operable exclusively to provide power to the crankshaft.

Abstract: A combined cleaning system to be used in a wet scrubber process for reducing SOX and NOX in exhaust gases from a combustion engine comprises an Exhaust Gas Cleaning (EGC) scrubber and an Exhaust Gas Recirculation (EGR) scrubber. The combined cleaning system further comprises a scrubber water circulation tank arranged to circulate scrubber water in an EGC scrubber process loop between the scrubber water circulation tank and the EGC scrubber and in an EGR scrubber process loop between the scrubber water circulation tank and the EGR scrubber. The EGR scrubber process loop comprises an arrangement for supply of a first alkaline agent to the flow of scrubber water and a first separator unit to separate particulate matter from the circulated scrubber water.

Abstract: Disclosed is an EGR mixer for mixing a fresh air flow and an EGR flow. The EGR mixer comprises an air duct configured to allow a fresh air flow to flow therethrough, and comprises an EGR duct configured to allow an EGR flow to flow therethrough. The EGR mixer comprises a mixing duct positioned downstream of the air duct and the EGR duct. The EGR mixer comprises a supplemental duct fluidly connecting the EGR duct to a second mixing section of the mixing duct. The EGR mixer is configured to mix the fresh air flow and the EGR flow into a mixed flow.

Abstract: An exhaust manifold for an internal combustion engine with exhaust turbocharging and an exhaust gas recirculation device, includes a header pipe with several inflow openings connected with the combustion chambers of the internal combustion engine via connecting pieces, and outlet openings branching from the header pipe via connecting branches for the exhaust gas recirculation and the exhaust turbocharger. To achieve a high exhaust gas recirculation rate and an effective pressurization of the exhaust turbocharger with exhaust gas, at least one flow guide element is arranged in the header pipe close to the outlet openings which divides the exhaust gas flow onto the two outlet openings in a targeted manner.

Abstract: An engine includes an EGR apparatus which refluxes a portion of exhaust gas from an exhaust manifold to an intake manifold as EGR gas. A differential pressure sensor detects a differential pressure between intake pressure of the intake manifold and exhaust pressure in the exhaust manifold. The differential pressure sensor is mounted on a head cover which covers an upper portion of a cylinder head. An intake pressure taking-out passage which is in communication with the intake manifold is formed in the cylinder head. An intake pressure introducing passage which is connected to the differential pressure sensor is formed in the head cover. The intake pressure taking-out passage and the intake pressure introducing passage are in communication with each other.

Abstract: Various methods and systems are provided for a hydraulically actuated engine valve. In one example, a method includes receiving an indication of a temperature of an exhaust flow exceeding a threshold temperature. The method further includes responsive to the indication, increasing a flow, in a hydraulically actuated valve system having a valve and an actuator in thermal communication with the exhaust flow, of hydraulic fluid through the actuator, to manage a temperature of the actuator.

Abstract: A vehicle is provided with an engine, an H2 and CO tank, a CO2 reclaimer, an electrolytic solution tank, an electrolyzer, a water tank and the like. During operation of the engine, an exhaust gas is introduced into an absorbing liquid in the CO2 reclaimer so as to recover CO2 in the exhaust gas and to store the same in the electrolytic solution tank. While supplying the absorbing liquid having absorbed CO2 and water to the electrolyzer from the electrolytic solution tank and the water tank, respectively, electric power is supplied to the electrolyzer. As a result, a mixed gas composed of CO and H2 from CO2 and water. The generated mixed gas is temporarily stored in the H2 and CO tank and is supplied to the engine.

Abstract: An exhaust gas recirculation device is provided. The device recirculates, from an exhaust system to an intake system, a part of exhaust gas from a plurality of cylinders of a multi-cylinder engine as EGR gas. The device includes a single EGR pipe extending from the exhaust system toward the intake system, an EGR manifold branching from a downstream end portion of the EGR pipe toward each cylinder, and an EGR valve for adjusting an EGR gas amount. The EGR manifold has one or more common EGR passages having a single pipe portion and branched pipe portions, and one or more independent EGR passages. Each shape of the common and independent EGR passages is set so that a communicating path in the EGR manifold communicating an arbitrary cylinder with a cylinder where combustion is performed subsequently thereto has the same volume for any cylinder combination having the adjacent combustion order.

Abstract: A method for controlling combustion in an engine is provided. The method comprises under a first condition, adjusting an EGR amount of a total cylinder charge in response to engine out NOx levels being below a first threshold. In this way, NOx levels may be used as feedback to control combustion stability.

Abstract: Methods and systems are provided for enabling engine dilution control. One or more engine diluents are combined to provide a desired engine dilution, the various diluents selected based on their respective combustion stability limits. A ratio of the various diluents used is further adjusted based on engine operating limitations.

Abstract: The engine boosting system includes an engine having an intake manifold, exhaust manifold and exhaust gas recirculation loop fluidly connected therebetween. A boost circuit including a storage vessel is in fluid communication with the intake manifold and with the exhaust manifold. A throttle is located downstream of the exhaust manifold, the exhaust gas recirculation loop, and the boost circuit. A connection between the boost circuit and the intake manifold is independent of a connection between the exhaust gas recirculation loop and the intake manifold.

Abstract: Methods are provided for controlling an engine. One method may include boosting engine intake air to a cylinder; and injecting an amount of a scavenging fluid into the cylinder based on an amount of cylinder residual exhaust gas. A scavenging fluid, such as water or windshield washer fluid evaporates on contact with the hot exhaust gases and hot metal components and the expanded volume of the vapor displaces the residual exhaust gas, thereby improving engine scavenging.

Abstract: An internal combustion engine system basically has an internal combustion engine, a reforming fuel injection device and a reformer. The internal combustion engine has an exhaust circulation path that is connected to an exhaust path and an intake path communicating with a combustion chamber. The reforming fuel injection device injects a reforming fuel into an exhaust gas flowing through the exhaust circulation path. The reformer has a reforming catalyst for generating a hydrogen-containing gas using the reforming fuel. The internal combustion engine system has a reforming catalyst regeneration device for causing an oxygen-containing gas to flow through the exhaust circulation path and thereby regenerate the reforming catalyst at a predetermined timing for regenerating the reforming catalyst.

Abstract: Systems and methods for exhaust gas recirculation are provided. The system includes a dedicated exhaust gas recirculation loop for recirculating exhaust gas flow from at least one dedicated cylinder of an engine into an intake system prior to combustion. The system further includes a low pressure exhaust gas recirculation loop for increasing the exhaust gas recirculation amount above that provided by the dedicated exhaust gas recirculation loop.

Abstract: A method includes operating a spark ignition engine and flowing low pressure exhaust gas recirculation (EGR) from an exhaust to an inlet of the spark ignition engine. The method includes interpreting a parameter affecting an operation of the spark ignition engine, and determining a knock index value in response to the parameter. The method further includes reducing a likelihood of engine knock in response to the knock index value exceeding a knock threshold value.

Abstract: An EGR valve includes a housing formed with a passage, a valve seat provided in the passage, a valve element seatable on the valve seat, a valve stem provided with the valve element at an end, and an actuator for making stroke movement of the valve stem. The valve element is moved together with the valve stem with respect to the valve seat to change an open area of a measuring section, thereby changing an opening degree of the valve element, to adjust a flow rate of EGR gas in the passage. The EGR valve has high-resolution flow-rate characteristics in a low opening region of the valve element and large flow-rate characteristics in a high opening region. The valve element and the valve seat have predetermined shapes to cause the flow-rate characteristics in the low opening region to change in a curve without a step.

Abstract: A control apparatus for an internal combustion engine is provided that can favorably determine a shut-off failure of an EGR valve under a high intake pressure condition in which an intake pressure becomes higher than an exhaust pressure. In a case where the high intake pressure condition and a transition condition are established at a time of a shut-off instruction on shutting off the EGR valve, it is determined that a shut-off failure of the EGR valve has occurred if an actual measurement value of the air-fuel ratio of exhaust gas detected by a main air-fuel ratio sensor is a value that is leaner by an amount equal to or greater than a predetermined lean determination value relative to a target value of the air-fuel ratio of the exhaust gas.

Abstract: In a stratification operation, O2 is injected from an oxygen injector during valve opening of an intake valve. Therefore, the injected O2 flows into a combustion chamber immediately after the injection, and forms a layer having a constant spread in the combustion chamber. Meanwhile, the working gas in the combustion chamber forms such a layer as to cover the O2 layer on a wall surface of the combustion chamber in conjunction with formation of the O2 layer. In other words, in the combustion chamber, an inner layer with a high O2 concentration and an outer layer with a high working gas concentration are respectively formed.

Abstract: A valve suitable for use as an exhaust gas recirculation valve in an engine includes a valve housing defining an interior space, a valve stem and a valve member, which may be a poppet, mounted on said valve stem. The valve member is arranged to move between open and closed positions. The valve further includes a mounting member, which may be a bush, located in the interior space, with said valve stem supported within the mounting member. The valve member includes a deflector to direct fluid away from the mounting member when the valve member is in an open position.

Abstract: An engine system for a machine is disclosed. The engine system may have an intake manifold configured to direct air into a donor cylinder and a non-donor cylinder of an engine. The engine system may also have a first exhaust manifold configured to direct exhaust from the non-donor cylinder to the atmosphere. The engine system may also have a second exhaust manifold configured to receive exhaust from the donor cylinder. The engine system may further have a control valve configured to selectively direct a first amount of exhaust from the second exhaust manifold to the intake manifold. In addition, the engine system may have an orifice configured to allow a second amount of exhaust to flow from the second exhaust manifold to the first exhaust manifold.

Abstract: A system includes an internal combustion engine having a number of cylinders, with at least one of the cylinders plumbed to have a complete recycle of the exhaust gases from the cylinder. The system further includes the completely recycled cylinder having an EGR stroke cycle, and the non-recycled cylinders of the engine having an exhaust stroke cycle. The system includes the EGR stroke cycle being distinct from the exhaust stroke cycle. An amount and composition of the exhaust gases from the recycled cylinder are distinct from the amount and composition of the exhaust gases from the non-recycled cylinders, at least at certain operating conditions of the engine.

Abstract: Methods and systems are provided for reducing EGR estimation errors during lean engine operating conditions. During lean engine operation, EGR is disabled if the estimated exhaust air-fuel ratio becomes leaner than a lean threshold. The lean threshold is adjusted based on an upper limit of EGR errors that may be tolerated by the engine at a given engine speed and load.

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: Disclosed is an exhaust gas recirculation (EGR) valve for a vehicle which achieves regulation of the flow rate of exhaust gas introduced into an engine and the flow rate of fresh air. The EGR valve includes a fresh air flow channel, an EGR flow channel connected to the fresh air flow channel and a valve unit configured to open or close the EGR flow channel and to selectively block the fresh air flow channel according to an opened/closed state of the EGR flow channel. The valve unit includes a first valve to open or close the EGR flow channel and a second valve arranged at one side of the first valve at a different angle from an arrangement angle of the first valve. The second valve is moved along with the first valve to selectively interfere with a flow stream of fresh air in the fresh air flow channel.

Abstract: A method of estimating a boost pressure of a turbocharger is disclosed. A throttle body temperature is estimated as a function of engine operating parameters. An intake air mass flow and an exhaust mass flow are estimated as a function of the throttle body temperature. A turbine inlet pressure and a turbine outlet pressure are estimated as a function of engine operating parameters. A turbine speed is estimated as a function of the intake air mass flow, exhaust mass flow and turbine inlet and outlet pressure. The boost pressure is estimated as a function of the turbine speed. Estimation of the maximum boost pressure of a turbocharged internal combustion engine is performed method cyclically as follows: estimating a throttle temperature, estimating an air mass flow and an exhaust mass flow, estimating a turbine inlet pressure and a turbine outlet pressure, estimating a turbine speed, and estimating the maximum boost pressure.

Abstract: A gas sensor assembly for sensing a pressure of a gas including a housing, a carrier, an electronic chip, a cap and a biasing apparatus. The housing has a wall defining cavity with a port open to the gas. The carrier is mounted to the wall in the cavity. The electronic chip is secured to the carrier on an opposed side from the port and includes a diaphragm portion exposed to the port. The cap is mounted to the chip on an opposed side from the carrier. The biasing apparatus is located between the cap and the wall of the housing, with the biasing apparatus being configured to bias the cap toward the chip whereby gas pressure acting against the diaphragm is opposed by the biasing apparatus.

Abstract: An intake manifold assembly includes an intake manifold body defining an interior manifold cavity. The intake manifold further includes a throttle mount coupled to the intake manifold body and defining a mount passage in fluid communication with the interior manifold cavity. The throttle mount is configured to be coupled to a throttle assembly. The intake manifold assembly further includes a supplemental gas conduit including a first supplemental gas conduit portion coupled to the intake manifold body. The supplemental gas conduit further includes a second supplemental gas conduit portion in fluid communication with the first supplemental gas conduit portion. The second supplemental gas conduit portion is coupled to the throttle mount and is configured to deliver supplemental gases into the mount passage to mix the supplemental gases with intake air flowing through the mount passage.

Abstract: In an exemplary embodiment, an internal combustion engine includes an oxidation catalyst configured to receive an exhaust gas flow from the internal combustion engine, a urea injector positioned downstream of the oxidation catalyst to inject a urea flow into the exhaust gas flow and a mixer positioned downstream of the urea injector to mix the exhaust gas flow and the urea flow to form a mixed exhaust gas and urea flow. The engine also includes a particulate filter and catalytic reduction assembly positioned downstream of the mixer to receive the mixed exhaust and urea flow from the mixer to form a treated exhaust gas flow and an exhaust gas recirculation system coupled to the particulate filter to receive a portion of the treated exhaust gas flow and recirculate the portion of the exhaust gas flow to be mixed with a fresh air flow for the internal combustion engine.

Abstract: Exhaust gas recirculation circuit comprising: at least one valve (100) comprising a body defining a first duct (1) opening into a second duct (2) thereby defining an intersection that forms a seat (7) at right angles to the second duct (2), a valve disk (8) that slides in the first duct (1) at right angles to the seat(7) between a closed position and an open position in which the valve disk (8) lies into close proximity to a wall (5) of the first duct (1) lying facing the seat (7), the valve (100) comprising means of actuating (12) the valve disk (8) from its closed position to its open position and an elastic spring mechanism bringing the valve disk (8) to its closed position, an exhaust pipe (24) connected to the first duct (1) of the valve (100), an intake pipe (31) connected to the second duct (2) of the valve (100), the circuit being arranged to define a flow direction for a gas flow from the first duct (1) to the second duct (2) in such a manner as the gas flow tends to bring the valve disk (8) in the c

Abstract: Methods and systems are provided for adjusting cylinder valve timings to enable a group of cylinders to operate and combust while another group of cylinders on a second are selectively deactivated. Valve timing may be adjusted to allow flow of air through the inactive cylinders to be reduced, lowering catalyst regeneration requirements upon reactivation. The valve timing may alternatively be adjusted to enable exhaust gas to be recirculated to the active cylinders via the inactive cylinders, providing cooled EGR benefits.

Abstract: Provided is a control device for an internal combustion engine equipped with a supercharger, including: operation state detection means for detecting an operation state of the internal combustion engine; overlap read means for reading a valve overlap period; collector pressure detection means for detecting a collector pressure; exhaust gas pressure estimation means for estimating an exhaust gas pressure on an upstream side of the supercharger; and scavenging amount estimation means for estimating a scavenging amount based on the operation state, the valve overlap period, the collector pressure, and the exhaust gas pressure.

Abstract: Devices, systems and methods for the preparation of an oxygenate compound or mixture of oxygenate compounds suitable for use in internal combustion engines are disclosed. An internal combustion engine system includes: a fuel system including an oxygenate compound synthesis device including a reactor including a catalyst, the oxygenate compound synthesis device being configured to convert at least a portion of a feedstock to an oxygenate compound or a mixture of oxygenate compounds; and an internal combustion engine configured to initiate combustion through compression or high energy discharge, the internal combustion engine including: a fuel injection system configured to provide fuel injection, and a cooling system configured to cool the internal combustion engine, the internal combustion engine being configured to heat the oxygenate compound synthesis device using heat from the cooling system of the internal combustion engine. Applications of the devices, systems and methods are also disclosed.

Abstract: A dual path fresh air system, having a first air supply path, the first path supplies air to at least one first cylinder set; a second air supply path, the second path supplies air to at least on second cylinder set; a first exhaust gas recirculation inlet fluidly connected to the first path to introduce recirculated exhaust gas into the first path; a second exhaust gas recirculation inlet fluidly connected to the second path to introduce recirculated exhaust gas into the second path; a first valve member, which is arranged upstream of the first exhaust gas recirculation inlet in the first path, wherein the first valve member controls fluid flowing through a cross section of the first path; and a second valve member which is arranged upstream of the second exhaust gas recirculation inlet in the second path, for controlling fluid flowing through a cross section of the second path.

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.