Abstract: The Rh content by percentage in an HC absorbent catalytic converter provided in an exhaust pipe is greater than the Rh content by percentage in an upstream three-way catalyst. In this way, even when HC which has been temporarily absorbed is emitted in an atmosphere and the exhaust gas becomes rich, the HC absorbent catalytic converter displays improved oxidization and removal of HC due to the high content by percentage of Rh which has a high HC conversion ratio in rich atmospheres. There is no necessity to control the air-fuel ratio to a strongly lean ratio and so HC removal can be improved while maintaining suppression of NOx emissions.

Abstract: A spark ignition engine (2) has a fuel injector (8) in an intake port (7). An engine rotation speed sensor (9) detects the rotation speed of the engine (2). The controller (1) determines the target fuel injection amount of the fuel injector (8) during startup of the engine (2) by correcting the basic injection amount in response to the trend in the variation in the engine rotation speed. When the rotation speed of the engine (2) decreases, the controller (1) sets the target fuel injection amount to be smaller than when the rotation speed of the engine (2) is increasing at an identical rotation speed. As a result, effects on the air-fuel ratio related to wall flow relative to fluctuations in the rotation speed of the engine (2) are eliminated and the control accuracy of the air-fuel ratio of the engine (2) is improved.

Abstract: A spark ignition internal combustion engine (2) performs ignition within a fixed ignition crank angle range. The operation control device comprises a programmable controller (1) and a unit crank angle sensor (9) outputting a unit crank angle signal on each unit crank angle. The controller (1) calculates the engine rotation speed based on the unit crank angle signals (S1). By preventing the calculation of the engine rotation speed based on the unit crank angle signals detected in the ignition crank angle range, errors in the calculation of the engine rotation speed resulting from engine ignition noise are eliminated and a precise engine rotation speed is obtained.

Abstract: A spark ignition internal combustion engine (2) performs ignition within a fixed ignition crank angle range. The operation control device comprises a programmable controller (1) and a unit crank angle sensor (9) outputting a unit crank angle signal on each unit crank angle. The controller (1) calculates the engine rotation speed based on the unit crank angle signals (S1). By preventing the calculation of the engine rotation speed based on the unit crank angle signals detected in the ignition crank angle range, errors in the calculation of the engine rotation speed resulting from engine ignition noise are eliminated and a precise engine rotation speed is obtained.

Abstract: A spark ignition engine (2) has a fuel injector (8) in an intake port (7). An engine rotation speed sensor (9) detects the rotation speed of the engine (2). The controller (1) determines the target fuel injection amount of the fuel injector (8) during startup of the engine (2) by correcting the basic injection amount in response to the trend in the variation in the engine rotation speed. When the rotation speed of the engine (2) decreases, the controller (1) sets the target fuel injection amount to be smaller than when the rotation speed of the engine (2) is increasing at an identical rotation speed. As a result, effects on the air-fuel ratio related to wall flow relative to fluctuations in the rotation speed of the engine (2) are eliminated and the control accuracy of the air-fuel ratio of the engine (2) is improved.

Abstract: The invention comprises at least two independent intake ports 14a, 14b connected to a combustion chamber 15, two intake valves 12a, 12b, and two exhaust valves 13a, 13b. Upper and lower channels 22a, 22b which are defined by a partition wall, and an intake control valve 25 for opening and closing the lower side channel 22b are provided in the interior of the first intake port 14a. An intake control valve 26 for opening and closing the first intake port 14b is also provided. The invention further comprises a controller 50 for controlling the opening and closing of the intake control valves 25 and 26, and the degree of opening of these intake control valves 25 and 26 is controlled in accordance with the operating conditions.

Abstract: The invention comprises at least two independent intake ports 14a, 14b connected to a combustion chamber 15, two intake valves 12a, 12b, and two exhaust valves 13a, 13b. A first fuel injection valve 31a is provided in the first intake port 14a and a second intake control valve 26 is provided for opening and closing the second intake port 14b. When the engine is in the cold condition, the second intake control valve 26 is slightly opened and fuel is injected from the first fuel injection valve 31b. Air-fuel mixture from the first intake port 14a and a smaller amount of fresh air from the second intake port 14b are introduced [into the combustion chamber], and the overall air-fuel ratio inside the combustion chamber is controlled to become slightly lean.

Abstract: The invention comprises at least two independent intake ports 14a, 14b connected to a combustion chamber 15, two intake valves 12a, 12b, and two exhaust valves 13a, 13b. A first fuel injection valve 31a is provided in the first intake port 14a and a second intake control valve 26 is provided for opening and closing the second intake port 14b. When the engine is in the cold condition, the second intake control valve 26 is slightly opened and fuel is injected from the first fuel injection valve 31b. Air-fuel mixture from the first intake port 14a and a smaller amount of fresh air from the second intake port 14b are introduced [into the combustion chamber], and the overall air-fuel ratio inside the combustion chamber is controlled to become slightly lean.

Abstract: The invention comprises at least two independent intake ports 14a, 14b connected to a combustion chamber 15, two intake valves 12a, 12b, and two exhaust valves 13a, 13b. Upper and lower channels 22a, 22b which are defined by a partition wall, and an intake control valve 25 for opening and closing the lower side channel 22b are provided in the interior of the first intake port 14a. An intake control valve 26 for opening and closing the first intake port 14b is also provided. The invention further comprises a controller 50 for controlling the opening and closing of the intake control valves 25 and 26, and the degree of opening of these intake control valves 25 and 26 is controlled in accordance with the operating conditions.

Abstract: The startup time of an engine is shortened by performing initial fuel injection after the start of cranking on a cylinder undergoing an intake stroke and a cylinder undergoing an exhaust stroke. After the initial fuel injection, HC emissions are suppressed by performing fuel injection in cylinders undergoing an exhaust stroke. Furthermore when it is determined that initial combustion has not occurred after the initial fuel injection, an additional injection is performed on the cylinder undergoing an intake stroke. In this manner, it is possible to minimize increases in the startup time and adverse effects on exhaust emissions.

Abstract: In order to improve the control characteristics for ignition timing during transient operating conditions including engine startup, during engine transient operating conditions, a controller (1) sets an advance limit ADVLMT restricting the maximum value of the ignition timing advance to a limit ADMLMTS which is a large value when compared to the value for steady-state operating conditions. Furthermore during transient operating conditions, the dwell angle TDWLLB is also increased and the correlation of the ignition timing control with respect to a suitable ignition timing is improved.

Abstract: In a four-stroke cycle multi-cylinder internal combustion engine (2), a controller (1) controls fuel injectors (8) to inject fuel for the cylinder (#1) in the intake stroke immediately after the first cylinder-stroke identification is performed. Due to this fuel injection control, the fuel is necessarily injected before the first combustion occasion at any cylinder (#1-#4), cylinder dependent fluctuation of air-fuel ratio when the first combustion takes place in the respective cylinders (#1-#4) is prevented. Further, in a predetermined low temperature range, the controller (1) controls fuel injectors (8) to perform a preliminary fuel injection for all the cylinders (#1-#4) before the first cylinder-stroke identification, so the fuel amount required for the first combustion is ensured for all the cylinders (#1-#4).

Abstract: An internal combustion engine (2) provided with a starter motor sequentially performs combustion of fuel in a plurality of cylinders (#1-#4). Each cylinder is provided with an intake port (7) and a fuel injector (8) to inject fuel in the intake port (7) and repeatedly performs an intake stroke, compression stroke, expansion stroke and an exhaust stroke. A sensor (9, 11) generates a signal identifying a cylinder in a specific position in a specific stroke and the controller (1) executes a cylinder-stroke identification in response to the signal. Upon the first execution of the cylinder-stroke identification when the engine is cranked, a fuel injection is performed for a cylinder in the intake stroke and for a cylinder in the exhaust stroke simultaneously so as to ensure the fuel supply amount required for the first combustion in each cylinder.

Abstract: A fuel injection control device for an internal combustion engine is provided with a controller functions to command the fuel injectors for a cylinder in the exhaust stroke and for a cylinder in the intake stroke to simultaneously perform a primary fuel injection, when the first cylinder-stroke identification is performed, if the engine temperature is higher than a predetermined temperature. The controller further functions to command the fuel injector only for a cylinder in the intake stroke to perform a primary fuel injection, when the first cylinder-stroke identification is performed, if the engine temperature is less than the predetermined temperature. Thus the startup time of the engine is shortened and the stability of startup is ensured at normal, low, or extremely low temperatures.

Abstract: An internal combustion engine (2) provided with a starter motor sequentially performs combustion of fuel in a plurality of cylinders (#1-#4). Each cylinder is provided with an intake port (7) and a fuel injector (8) to inject fuel in the intake port (7) and repeatedly performs an intake stroke, compression stroke, expansion stroke and an exhaust stroke. A sensor (9, 11) generates a signal identifying a cylinder in a specific position in a specific stroke and the controller (1) executes a cylinder-stroke identification in response to the signal. Upon the first execution of the cylinder-stroke identification when the engine is cranked, a fuel injection is performed for a cylinder in the intake stroke and for a cylinder in the exhaust stroke similtaneously so as to ensure the fuel supply amount required for the first combustion in each cylinder.

Abstract: The startup time of an engine is shortened by performing initial fuel injection after the start of cranking on a cylinder undergoing an intake stroke and a cylinder undergoing an exhaust stroke. After the initial fuel injection, HC emissions are suppressed by performing fuel injection in cylinders undergoing an exhaust stroke. Furthermore when it is determined that initial combustion has not occurred after the initial fuel injection, an additional injection is performed on the cylinder undergoing an intake stroke. In this manner, it is possible to minimize increases in the startup time and adverse effects on exhaust emissions.

Abstract: A fuel injection control device for an internal combustion engine is provided with a controller functions to command the fuel injectors for a cylinder in the exhaust stroke and for a cylinder in the intake stroke to simultaneously perform a primary fuel injection, when the first cylinder-stroke identification is performed, if the engine temperature is higher than a predetermined temperature. The controller further functions to command the fuel injector only for a cylinder in the intake stroke to perform a primary fuel injection, when the first cylinder-stroke identification is performed, if the engine temperature is less than the predetermined temperature. Thus the startup time of the engine is shortened and the stability of startup is ensured at normal, low, or extremely low temperatures.

Abstract: In a four-stroke cycle multi-cylinder internal combustion engine (2), a controller (1) controls fuel injectors (8) to inject fuel for the cylinder (#1) in the intake stroke immediately after the first cylinder-stroke identification is performed. Due to this fuel injection control, the fuel is necessarily injected before the first combustion occasion at any cylinder (#1-#4), cylinder dependent fluctuation of air-fuel ratio when the first combustion takes place in the respective cylinders (#1-#4) is prevented. Further, in a predetermined low temperature range, the controller (1) controls fuel injectors (8) to perform a preliminary fuel injection for all the cylinders (#1-#4) before the first cylinder-stroke identification, so the fuel amount required for the first combustion is ensured for all the cylinders (#1-#4).

Abstract: In order to improve the control characteristics for ignition timing during transient operating conditions including engine startup, during engine transient operating conditions, a controller (1) sets an advance limit ADVLMT restricting the maximum value of the ignition timing advance to a limit ADMLMTS which is a large value when compared to the value for steady-state operating conditions. Furthermore during transient operating conditions, the dwell angle TDWLLB is also increased and the correlation of the ignition timing control with respect to a suitable ignition timing is improved.

Abstract: A controller (6) controls an air-fuel ratio of an engine (1) so that an oxygen storage amount of a catalyst (3) provided in an exhaust passage (2) is maintained constant. At this time, the controller (6) computes or estimates the oxygen storage amount separately for a first amount and a second amount, where the first amount is estimated based on a relationship between the first and second amount. The controller (6) controls the air/fuel ratio based on the estimated first amount.