A two-stroke engine (4) has a throttle motor (22) for driving a throttle valve (20), a fuel injection device (430) disposed in an intake system (18) including a crank chamber (420), and a control unit (24) controlling the throttle motor (22) and the fuel injection device. The two-stroke engine (4) is designed to achieve an engine rotation speed of 4,500 rpm to 7,000 rpm when the throttle valve (20) is fully open. The two-stroke engine (4) is operated with the throttle full open by the control unit (24), and a battery (8) is charged with electric power generated by a generator (6) using the two-stroke engine.

Methods and systems are provided for balancing a plurality of fuel injectors via a diagnostic. In one example, a method may include adjusting a fuel injection pattern to increase an occurrence of a fuel injection being preceded by a same-cylinder bank fuel injection. The method may further include skipping fuel injections resulting in the fuel injection being preceded by an opposite-cylinder bank fuel injection.

A control method for internal combustion engine with a fuel injection valve configured to directly inject fuel into a cylinder and an ignition plug configured to directly spark-ignite the fuel injected from the fuel injection valve includes comparing an actual behavior, which is an actual changing behavior of an engine revolution speed at an engine start, to a reference behavior set in advance, and switching from stratified combustion in which a fuel spray injected from the fuel injection valve and staying around the ignition plug is directly spark-ignited to homogeneous combustion in which a homogeneous air-fuel mixture is formed in a combustion chamber and the fuel is burned and increasing a mechanical compression ratio of the internal combustion engine as compared to the case where the actual behavior and the reference behavior match if the actual behavior is different from the reference behavior.

An internal combustion engine control apparatus including a microprocessor. The microprocessor is configured to perform determining whether a warm-up of an exhaust catalyst device disposed on an exhaust passage of an internal combustion engine is complete; acquiring an information on a temperature inside a cylinder of the internal combustion engine; switching an injection mode to a first injection mode or a second injection mode in accordance with an information on a temperature inside the cylinder when it is determined that a warm-up of the exhaust catalyst device is complete; and controlling a fuel injector so as to inject the fuel in accordance with an injection mode.

A control unit controls a combustion state of an internal combustion engine in accordance with a drive torque requested by a driver. The control unit performs a switching control to switch at least a combustion state between lean-burn combustion and stoichiometric combustion. A monitor unit performs torque monitoring to determine abnormality of a request torque, which is requested to the internal combustion engine, and a generated torque of the internal combustion engine based on the request torque and an estimation torque, which is an estimation value of an actual torque of the internal combustion engine. A combustion state determining unit determines whether the combustion state in the control unit is the lean-burn combustion or the stoichiometric combustion. A computing unit computes the estimation torque in accordance with the combustion state determined by the combustion state determining unit.

During a transient period, the opening degree of a throttle valve (throttle opening degree) is varied from a steady-period target throttle opening degree in a region A1 toward a valve closing side by a predetermined amount P, and is thereafter controlled so as to become a steady-period target throttle opening degree in the region A1. The transient period is a transient period in which the operation state is shifted from a region B2 in which an air-fuel ratio in a supercharged state becomes a predetermined lean air-fuel ratio to a region A1 in which the air-fuel ratio in a non-supercharged state becomes a predetermined rich air-fuel ratio richer than the lean air-fuel ratio. In this transient period, by reducing the air amount in a cylinder, the combustion torque of an internal combustion engine is suppressed, and consequently; a torque overshoot can be suppressed.

An internal combustion engine (1) is provided with a turbocharger (2), and is configured to be switchable between a stoichiometric combustion mode having a theoretical air-fuel ratio as a target air-fuel ratio and a lean combustion mode having a lean air-fuel ratio as a target air-fuel ratio. An air bypass valve (20) is provided in an air bypass passage (19) communicating a collector (11a) on the downstream of a throttle valve (12) with the upstream side of a compressor (2b) in an intake passage (11). At the time of the shifting from the lean combustion mode to the stoichiometric mode, the throttle valve (12) is closed and the air bypass valve (20) is temporarily opened to decrease the pressure inside the collector (11a) quickly.

An acquisition unit acquires a required torque and an operating state of an internal combustion engine. A control unit is configured to: control operation of the internal combustion engine by using a required air amount, a required fuel amount, and a required ignition timing; acquire a required air amount by using the acquired required torque and a target air-fuel ratio of an air system determined according to the operating state; perform torque fluctuation correction on the target air-fuel ratio of the air system to determine a target air-fuel ratio of an injection system to reduce a difference between the required torque and an actual torque in a transition period between stoichiometric combustion and lean combustion; acquire a required fuel amount and a required ignition timing by using the determined target air-fuel ratio of the air system and the determined target air-fuel ratio of the injection system.

A control apparatus for an internal combustion engine includes an electronic control unit configured to i) perform a fuel introduction process, ii) calculate a total injection amount in the fuel introduction process, and control each of fuel injection valves based on a required injection amount per cylinder when the fuel introduction process is performed, and iii) perform a cylinder deactivation process for stopping fuel from being injected for one or some of cylinders, and controlling each of the fuel injection valves such that an amount of the fuel obtained by dividing the total injection amount is injected for a cylinder or cylinders other than the one or some of the cylinders for which the fuel is stopped from being injected, when the fuel introduction process is performed.

In an internal combustion engine which performs a homogeneous lean combustion mode and a stratified lean combustion mode, there is provided a new internal combustion engine control device capable of obtaining a stable combustion state by decreasing influences of delay of an air flow and a degree of change of a transient state and smoothly performing switching between the homogeneous lean combustion mode and the stratified lean combustion mode. Accordingly, in the present invention, when switching between the stratified lean mode in which a compression stroke injection is performed by a direct injection injector 7 and the homogeneous lean combustion mode in which an intake stroke injection is performed by the direct injection injector 7 is performed, a predetermined delay time t is provided from at least a switching operation of a tumble control valve 6, a switching operation between the compression stroke injection and the intake stroke injection is performed, and the delay time t is set so as to correspond to a magnitude of the degree of change L of the transient state. A switching timing between the compression stroke injection and the intake stroke injection is controlled according to the flow delay of an air control system such as the tumble control valve 6 and the degree of change L of the transient state, and thus, it is possible to improve combustion stability in a combustion chamber.