A negative pressure control valve (44) is disposed in a part of an intake passage (12) upstream of a confluence (30) of an EGR passage (27) and the intake passage (12). When in an EGR region (Regr) where an EGR gas is recirculated to the intake passage (12) through the EGR passage (27), the negative pressure control valve (44) is controlled in a manner to ensure a differential pressure between an exhaust passage (13) and the intake passage (12). When in an operation region (R2) lower in load than the EGR region (Regr), the negative pressure control valve (44) is controlled in a closing direction so as to suppress occurrence of noise.

Methods and systems are provided for operating a cylinder with a series gap igniter coupled to an ion sensing module. In one example, a method may include determining a location of an initial combustion in a cylinder from a series gap igniter based on a pressure rise rate in the cylinder, the ignition spark initiating combustion in the cylinder; and adjusting at least one setting of the cylinder based on the determined location. In this way, combustion stability and efficiency may be increased without increasing a cost and complexity of the engine.

Methods and systems are provided for diagnosing a humidity sensor in an engine. In one example, a method may include heating intake air entering an intake passage of an engine using heat recirculated from an exhaust system of the engine. A response of the humidity sensor to the heating of the intake air may be used to assess an integrity of the humidity sensor.

One embodiment is a system comprising an engine including a dedicated EGR cylinder configured to provide EGR to the engine via an EGR loop, a non-dedicated cylinder, a plurality of injectors structured to inject fuel into the dedicated EGR cylinder and the non-dedicated EGR cylinder, and an electronic control system operatively coupled with the fueling system and the ignition system. The electronic control system is configured to evaluate engine operating parameters including an engine load and an engine speed. The electronic control system is responsive to variation of the engine operating parameters to control operation of the fueling system to vary combustion in the at least one dedicated cylinder between rich of stoichiometric and stoichiometric.

The invention relates to a control method that allows the mean quantity of nitrogen oxides per kilometer covered emitted by a vehicle fitted with an internal combustion engine associated with a post-treatment system to be kept below a predefined fixed threshold, for any journey made by the vehicle. The mean quantity emitted over a fixed elementary distance that has just been covered by the vehicle is calculated iteratively, together with a long-term conformity factor which is equal to the mean quantity emitted over the entire distance covered since the start of the journey. When it is found that the long-term conformity factor is above the threshold, the engine and/or the post-treatment system is regulated in such a way as to obtain, over the next fixed elementary distance, a mean quantity of nitrogen oxides per kilometer that is lower than the threshold value FC, for example equal to 90% of the threshold, whatever the engine operating point. Thus, the long-term conformity factor converges towards the threshold.

Exhaust particulates are collected by a GPF(gasoline particulate filter) device. EGR control is executed, and exhaust gas flowing through an exhaust passage upstream of the GPF device is introduced into an intake passage via an EGR passage. In the EGR control, an opening area of the EGR passage is controlled to reduce the opening area of the EGR passage according to an operating state of the engine as a particulate deposition amount in the GPF device is increased.

An engine unit includes: an engine that is able to independently inject fuel into cylinders; an exhaust gas recirculation device that recirculates exhaust gas of the engine to intake air; a cleaning device that cleans exhaust gas from the engine; and a control device that controls the engine and the exhaust gas recirculation device. The control device performs control such that an amount of exhaust gas recirculated to intake air is less when fuel cutoff is performed for some cylinders out of all cylinders of the engine than when fuel is injected into all the cylinders of the engine.

The invention relates to a method for operating an internal combustion engine system (2), wherein the internal combustion engine system (2) is provided with an air intake duct (3), an exhaust gas duct (4) and an exhaust gas recirculation (EGR) system (5), wherein the EGR system (5) comprises an EGR conduit (6) that fluidly connects the exhaust duct (4) and the intake duct (3), and wherein a gas feeding device (7) configured to feed exhaust gas from the exhaust duct (4) to the intake duct (3) is arranged in the EGR conduit (6). The method is characterized in that it comprises the step of: providing a flushing liquid in the EGR conduit (6) upstream of the EGR gas feeding device (7) so as to flush and clean the EGR gas feeding device (7). The invention also relates to an internal combustion engine system (2) configured for being operated by such a method and to a vehicle (1) provided with such an engine system (2). The invention further relates to means for controlling the above method.

The invention provides a method for controlling an internal combustion engine (2) for controlling an internal combustion engine (2) comprising at least one first cylinder (201) and at least one second cylinder (202) with respective reciprocating pistons, an intake guide (305) arranged to guide air from a fresh air intake arrangement (303) to the first and second cylinders (201, 202), a fuel system (801, 802) arranged to inject fuel into the first and second cylinders (201, 202), a first exhaust guide (401) and a second exhaust guide (402) arranged to guide gases from the first and second cylinders (201, 202), respectively, towards an exhaust after treatment system (7), the method comprising—receiving (S1) in the first cylinder (201), from the intake guide (305), air from the fresh air intake arrangement (303) or gases including air from the fresh air intake arrangement (303),—expelling from the first cylinder (201), to the first exhaust guide (401), gases in the form of the air received in the first cylinder, or in the form of exhaust gases from combustions in the first cylinder, including a portion of the air received in the first cylinder (201),—controlling (S4) a first exhaust valve (411) located in the first exhaust guide (401) so as to reduce or inhibit the transport of the gases from the first cylinder (201) to the exhaust after treatment system (7) and simultaneously recirculating the gases from the first exhaust guide (401) to the intake guide (305) by means of an exhaust gas recirculating (EGR) passage (404),—receiving in the second cylinder (202), from the intake guide (305), at least a portion of the gases recirculated from the first exhaust guide (401) to the intake guide (305),—injecting (S5) fuel into the second cylinder (202) so as to provide repetitive combustions with air in the received gases,—expelling from the second cylinder (202), to the second exhaust guide (402), the exhaust gases produced by the combustions in the second cylinder (202), and—controlling a second exhaust valve (412) located in the second exhaust guide (402) so as to guide the exhaust gases expelled from the second cylinder through the second exhaust guide (402) towards the exhaust after treatment system (7).

Systems and methods for estimating an engine event location are disclosed herein. In one embodiment, a control system is configured to receive feedback from at least one vibration sensor coupled to a reciprocating engine, estimate an engine parameter based at least on the feedback and an Empirical Transform Function (ETF), estimate a location of an engine event based on the engine parameter, and adjust operation of the reciprocating engine based at least on the location of the engine event.