Abstract: A basic opening (A0) of an EGR control valve (22) is set, based on a current engine operation state. A differential pressure (?P1) across the EGR control valve (22) is calculated, based on an actual exhaust system temperature (T1) sensed by an exhaust temperature sensor (33). A reference differential pressure (?P0) is calculated, which is a differential pressure across the EGR control valve (22) in a steady state corresponding to the current engine operation state. A reference pulsation amplitude (D) is calculated, which is an amplitude of pulsation of the reference differential pressure (?P0). The basic opening (A0) is corrected, based on the differential pressure (?P1), the reference differential pressure (?P0), and the reference pulsation amplitude (D).

Abstract: 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.

Abstract: In inline four cylinder internal combustion engine (1), exhaust ports for a #2 cylinder and a #3 cylinder merge inside cylinder head (3) and form an opening serving as a single collective exhaust port. Exhaust manifold (5) has individual exhaust pipes (6, 7) for #1 and #4 cylinders and collective exhaust pipe (8), and the leading ends of these three exhaust pipes (6, 7, 8) are connected to catalytic converter (11). Exhaust gas introduction angle (?2) of each of individual exhaust pipes (6, 7) is larger by 30-60 degrees than exhaust gas introduction angle (?1) of collective exhaust pipe (8). Consequently, flow velocity distribution and temperature distribution in a catalyst carrier become uniform.

Abstract: In an in-line four-cylinder internal combustion engine, exhaust ports (2b, 2c) of cylinders #2 and #3 merge together inside a cylinder head and become open as one flat collective exhaust port (2bc). An exhaust manifold (5) includes separate individual exhaust pipes (6, 7) for cylinders #1 and #4 and a collective exhaust pipe (8) for cylinders #2 and #4. Tip ends of these three exhaust pipes are connected to a catalytic converter (11). An equivalent diameter of the collective exhaust port (2bc) is larger than equivalent diameters of the exhaust ports (2a, 2d) before merging. A short diameter of the collective exhaust port (2bc) is smaller than or equal to the equivalent diameters of the exhaust ports (2b, 2c).

Abstract: An internal combustion engine includes an intake passage of the internal combustion engine, an exhaust passage of the internal combustion engine, an EGR passage connecting the intake passage and the exhaust passage. The internal combustion engine further includes a throttle valve provided downstream of a connected part to the EGR passage in the intake passage, and configured to control a quantity of intake air flowing into the internal combustion engine, and an intake throttle valve provided upstream of the connected part to the EGR passage in the intake passage. A control device controls the internal combustion engine, in which device an opening degree of the intake throttle valve is determined on the basis of an intake air quantity.

Abstract: An internal combustion engine includes an intake passage of the internal combustion engine, an exhaust passage of the internal combustion engine, and an EGR passage connecting the intake passage and the exhaust passage. The internal combustion engine further includes a throttle valve provided downstream of a connected part to the EGR passage in the intake passage, and configured to control an intake air quantity toward a downstream side of the connected part, and an intake throttle valve provided upstream of the connected part to the EGR passage in the intake passage. In a control device of the internal combustion engine, an opening degree of the intake throttle valve is determined on the basis of an opening degree of the throttle valve.

Abstract: An exhaust gas recirculation control method of an internal combustion engine, the internal combustion engine including: a turbo supercharger; an exhaust gas recirculation passage communicating an exhaust passage with an intake passage at a part upstream of a compressor of the turbo supercharger; an exhaust gas recirculating amount control valve disposed in the exhaust gas recirculation passage; a differential pressure generating valve disposed upstream of a merging portion of fresh air gas and exhaust gas in the intake passage; and a controller adapted to control an opening of the exhaust gas recirculation amount control valve and an opening of the differential pressure generating valve, wherein in the method, the controller cooperatively controls the opening of the exhaust gas recirculation amount control valve and the opening of the differential pressure generating valve to make an exhaust gas recirculation ratio change to a target exhaust gas recirculation ratio at a change rate that prevents abnormal comb

Abstract: In an in-line four-cylinder internal combustion engine, exhaust ports (2b, 2c) of cylinders #2 and #3 merge together inside a cylinder head and become open as one flat collective exhaust port (2bc). An exhaust manifold (5) includes separate individual exhaust pipes (6, 7) for cylinders #1 and #4 and a collective exhaust pipe (8) for cylinders #2 and #4. Tip ends of these three exhaust pipes are connected to a catalytic converter (11). An equivalent diameter of the collective exhaust port (2bc) is larger than equivalent diameters of the exhaust ports (2a, 2d) before merging. A short diameter of the collective exhaust port (2bc) is smaller than or equal to the equivalent diameters of the exhaust ports (2b, 2c).

Abstract: In inline four cylinder internal combustion engine (1), exhaust ports for a #2 cylinder and a #3 cylinder merge inside cylinder head (3) and form an opening serving as a single collective exhaust port. Exhaust manifold (5) has individual exhaust pipes (6, 7) for #1 and #4 cylinders and collective exhaust pipe (8), and the leading ends of these three exhaust pipes (6, 7, 8) are connected to catalytic converter (11). Exhaust gas introduction angle (?2) of each of individual exhaust pipes (6, 7) is larger by 30-60 degrees than exhaust gas introduction angle (?1) of collective exhaust pipe (8). Consequently, flow velocity distribution and temperature distribution in a catalyst carrier become uniform.

Abstract: Provided is an internal combustion engine including two intake valves for each cylinder, the internal combustion engine including: a fixed cam for driving one of the two intake valves with a lift characteristic having a valve opening timing close to a top dead center; a variable valve actuation mechanism capable of changing, in accordance with an engine running condition, lift characteristics between a low-lift characteristic having an event angle and a lift amount each being smaller than an event angle and a lift amount of the fixed cam, and a high-lift characteristic having the event angle and the lift amount each being larger than the event angle and the lift amount of the fixed cam; and a variable cam for driving another of the two intake valves, the variable cam including the variable valve actuation mechanism, in which the variable valve actuation mechanism is configured to set the lift characteristic of the variable cam so as to obtain a valve opening timing on a retard side relative to the valve openi

Abstract: Provided is an internal combustion engine including two intake valves for each cylinder, the internal combustion engine including: a fixed cam for driving one of the two intake valves with a lift characteristic having a valve opening timing close to a top dead center; a variable valve actuation mechanism capable of changing, in accordance with an engine running condition, lift characteristics between a low-lift characteristic having an event angle and a lift amount each being smaller than an event angle and a lift amount of the fixed cam, and a high-lift characteristic having the event angle and the lift amount each being larger than the event angle and the lift amount of the fixed cam; and a variable cam for driving another of the two intake valves, the variable cam including the variable valve actuation mechanism, in which the variable valve actuation mechanism is configured to set the lift characteristic of the variable cam so as to obtain a valve opening timing on a retard side relative to the valve openi

Abstract: A sub collector is connected to a main collector disposed downstream of a throttle valve in an intake passage and a control valve for collector capacity disposed between the two collectors controls connection therebetween. A difference in pressure between the two collectors is reduced when a condition that pressure in the sub collector is lower than a predetermined value in relation to pressure in the main collector occurs. Namely, the control valve is forcibly opened at a point from a fully closed position of the throttle valve to acceleration operation thereof.

Abstract: A sub collector is connected to a main collector disposed downstream of a throttle valve in an intake passage and a control valve for collector capacity disposed between the two collectors controls connection therebetween. A difference in pressure between the two collectors is reduced when a condition that pressure in the sub collector is lower than a predetermined value in relation to pressure in the main collector occurs. Namely, the control valve is forcibly opened at a point from a fully closed position of the throttle valve to acceleration operation thereof.

Abstract: An internal combustion engine comprises intake and exhaust valves. An electromagnetic actuator is provided for actuating each intake valve so that the intake valve makes its opening and closing action. A control unit is provided for controlling the electromagnetic actuator in accordance with engine operating conditions. The control unit is arranged to control the electromagnetic actuator in a manner to cause the intake valve to make first and second opening and closing actions in an intake stroke in synchronism with intake air pulsation. The first opening and closing action is before in time the second opening and closing action.