An electronic control method for a throttle performed by an electronic control throttle device is disclosed. The electronic control method includes: generating, by the electronic control section, the control signal for the throttle with a sum of a proportional torque and an integral torque as a value of a torque command, by calculating an engine speed deviation from a difference between a calculated or input engine speed and an input engine speed command; calculating an engine rotational angular acceleration based on the engine speed; obtaining the proportional torque from a product of the engine speed deviation and a predetermined coefficient; and obtaining the integral torque by integrating the product of the engine speed deviation and the predetermined coefficient.

Methods and systems are provided for user controlled engine revving. In one example, the engine may be revved to a peak speed according to a target revving sequence in response to a user-initiated command. A revving sound may be provided in response to an input device, without demanding manual depression of an accelerator pedal.

A CPU determines that there is a misfire when a relative magnitude of a rotation fluctuation amount ΔT30[0] related to a cylinder subject to the determination in relation to a rotation fluctuation amounts ΔT30[4] of the previous combustion cycle is greater than or equal to the determination value Δth. However, during the execution of a catalyst warm-up process, the CPU uses, in the comparison, the relative magnitude of the rotation fluctuation amount ΔT30[0] in relation to the average ΔT30ave[0] of the smallest five of the rotation fluctuation amounts ΔT30[4] to ΔT30[40] from the past ten combustion cycles.

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.

To provide a controller and a control method for internal combustion engine which can set appropriately an angle interval for estimating the combustion state in accordance with change of a burning angle interval, and can reduce calculation processing load for estimation of the combustion state. A controller for internal combustion engine changes the estimation crank angle interval based on an operating condition of the internal combustion engine; calculates an increment of gas pressure torque by burning at each crank angle of the estimation crank angle interval; and estimates the combustion state of the internal combustion engine, based on the increment of gas pressure torque by burning in the estimation crank angle interval.

A CPU performs a regeneration process for a GPF by stopping combustion control of cylinder #1 and causing an air-fuel ratio of an air-fuel mixture in the other cylinders to be richer. The CPU calculates a rotational fluctuation amount which is used to detect random misfires in which a misfire rate in a predetermined period is equal to or greater than a predetermined proportion by calculating a difference in time et3txdh in which a crank shaft rotates by 30°CA. At the time of performing the regeneration process, the CPU calculates the rotational fluctuation amount based on a value obtained by removing an influence of torsion of a damper from the time et3txdh. When the influence of torsion is removed, 0.5th-order rotation and harmonics thereof are selectively used using a filter process.

The invention relates to a method for diagnosing and/or controlling a reciprocating engine having a variable compression ratio, wherein the method comprises the working steps: determining (S30) a first value (U.sub.1,1, U.sub.1,2; Δ.sub.1) of a rotational irregularity parameter of a crankshaft (1) of the reciprocating engine; and determining (S60) a value of a compression ratio parameter for the reciprocating engine based on said first rotational irregularity parameter value.

A variable combustion cylinder ratio control device includes a target ratio setting section and a pattern determining section. The pattern determining section determines a target deactivation interval as a subsequent deactivation interval when the difference between a current deactivation interval and the target deactivation interval is less than or equal to X cylinders, and determines, as the subsequent deactivation interval, an interval closer to the target deactivation interval than the current deactivation interval by X cylinders when the difference between the current deactivation interval and the target deactivation interval exceeds X cylinders. The value of X is a natural number and a variable value that varies in accordance with the operating state of the engine.

Provided is an internal combustion engine control unit that controls an engine by detecting combustion characteristics with a simple configuration robust to disturbance such as noise. Therefore, the internal combustion engine control unit (ECU 12) of the present embodiment includes a rotational speed calculation unit 122a that calculates a crank rotational speed of an internal combustion engine (engine 1); an extreme value timing calculation unit 122b that calculates an extreme value timing of the crank rotational speed calculated by the rotational speed calculation unit 122a; and a combustion state estimation unit (combustion phase calculation unit 122c) that estimates a combustion state based on the extreme value timing of the crank speed calculated by the extreme value timing calculation unit 122b.

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.