Methods and systems are provided for adjusting combustion parameters to increase combustion stability during conditions when condensate formed in a charge air cooler may enter cylinders of an engine. In response to increased mass air flow and a condensate level in the charge air cooler, the engine may combust a rich air-fuel ratio while increasing a positive valve overlap.

Methods and systems are provided for adjusting combustion parameters to increase combustion stability during conditions when condensate formed in a charge air cooler may enter cylinders of an engine. In response to increased mass air flow and a condensate level in the charge air cooler, the engine may combust a rich air-fuel ratio while increasing a positive valve overlap.

When it is determined that the initial combustion is unstable, the engine speed is forcibly increased. When the engine speed is forcibly increased, fluidity in the cylinder increases. When the fluidity in the cylinder rises, homogeneity of the homogeneous air-fuel mixture is improved. Therefore, it is possible to enlarge the flame kernel. When the flame kernel is enlarged, the initial flame resulting from the flame kernel is also enlarged. Then, the initial flame becomes easy to involve the closest fuel spray thereby the initial combustion can be stabilized.

When it is determined that the initial combustion is unstable, the engine speed is forcibly increased. When the engine speed is forcibly increased, fluidity in the cylinder increases. When the fluidity in the cylinder rises, homogeneity of the homogeneous air-fuel mixture is improved. Therefore, it is possible to enlarge the flame kernel. When the flame kernel is enlarged, the initial flame resulting from the flame kernel is also enlarged. Then, the initial flame becomes easy to involve the closest fuel spray thereby the initial combustion can be stabilized.

In a method for controlling an engine (1), based on a control map (75) of an engine speed N and a fuel injection amount Q of a common-rail fuel injection unit (3), a controller (7) calculating the fuel injection amount Q depending on the engine speed N, calculating an injection amount deviation Qn as a fuel injection amount increase, and determining that an engine is in a transient state if the injection amount deviation Qn exceeds a reference transient injection amount deviation A2 or if a transient injection amount deviation count Xq is larger than or equal to a reference transient injection amount deviation count X2. If it is determined that the engine is in the transient state, the controller controls an EGR unit (4) and a boost controller (8) according to an excess air ratio that is an indicator indicating the state of the engine.

An ECU makes an opening degree of a throttle valve larger than an opening degree in an idle rotating state of an engine in a rotation drop period during which engine speed drops to zero after combustion of the engine is stopped. Further, the ECU determines that the engine speed is within a predetermined rotation speed range including at least a resonance range of the engine in the rotation drop period, and, in the case where it is determined that the engine speed is within the predetermined rotation speed range, the ECU performs rotation drop processing of temporarily increasing a drop rate of the engine speed.

Provided is an in-combustion chamber flow control device used in an engine having an intake passage connected to an intake opening formed in a ceiling surface of a combustion chamber, at an angle inclined with respect to a direction of an axis of a cylinder. This in-combustion chamber flow control device comprises a plasma actuator (28) disposed inside the combustion chamber (16). The plasma actuator comprises: a dielectric body (38) disposed along the ceiling surface (16a) of the combustion chamber, at a position closer to a center of the ceiling surface than the intake opening (18a); an exposed electrode (40) disposed on one side of the dielectric body facing the combustion chamber; and an embedded electrode (42) disposed on a side opposite to the exposed electrode across the dielectric body. The embedded electrode is disposed at a position closer to the intake opening than the exposed electrode.

The control device 80 for an internal combustion engine comprises a control unit 81 configured to perform control processing comprising, during warming-up of the internal combustion engine 10, advancing valve opening timing and valve closing timing of an exhaust valve 18 of the internal combustion engine 10 with respect to respective preset reference values thereof, and retarding fuel injection timing of the internal combustion engine 10 with respect to a preset reference value thereof. According to this control device 80 for the internal combustion engine, warming-up of the internal combustion engine 10 can be effectively facilitated, and the warming-up time of the internal combustion engine 10 can thus be shortened.

The control device 80 for an internal combustion engine comprises a control unit 81 configured to perform control processing comprising, during warming-up of the internal combustion engine 10, advancing valve opening timing and valve closing timing of an exhaust valve 18 of the internal combustion engine 10 with respect to respective preset reference values thereof, and retarding fuel injection timing of the internal combustion engine 10 with respect to a preset reference value thereof. According to this control device 80 for the internal combustion engine, warming-up of the internal combustion engine 10 can be effectively facilitated, and the warming-up time of the internal combustion engine 10 can thus be shortened.

An internal combustion engine control device equipped with air cylinders and an EGR mechanism that returns exhaust gas emitted from the air cylinders to the intake side of the air cylinders is provided. The internal combustion engine control device includes an EGR control unit that controls the EGR flow volume of the EGR mechanism, and a humidity detection unit that directly or indirectly detects the humidity of outside air supplied to the air cylinders. The EGR control unit calculates the moisture amount in the outside air and the moisture amount in the recirculated exhaust gas, and controls the EGR mechanism on the basis of: a stable combustion limit air cylinder mass, which is set in accordance with the combustion state in the air cylinders; the mass of the air introduced into the air cylinders; the mass of the fuel; and the moisture amounts.