An engine system control apparatus includes a parameter reception unit that receives parameters necessary for acquiring a pressure ratio of the low-pressure compressor and a pressure ratio of the high-pressure compressor, a pressure ratio acquisition unit that acquires the pressure ratio of the low-pressure compressor and the pressure ratio of the high-pressure compressor based on the parameters, an inter-compressor pressure ratio acquisition unit that acquires an inter-compressor pressure ratio obtainable by dividing the pressure ratio of the high-pressure compressor by the pressure ratio of the low-pressure compressor, and a control unit that controls the exhaust gas flowrate adjustment unit such that the inter-compressor pressure ratio becomes a predetermined pressure ratio for optimizing an operation efficiency of the engine system.

An engine system control apparatus includes a parameter reception unit that receives parameters necessary for acquiring a pressure ratio of the low-pressure compressor and a pressure ratio of the high-pressure compressor, a pressure ratio acquisition unit that acquires the pressure ratio of the low-pressure compressor and the pressure ratio of the high-pressure compressor based on the parameters, an inter-compressor pressure ratio acquisition unit that acquires an inter-compressor pressure ratio obtainable by dividing the pressure ratio of the high-pressure compressor by the pressure ratio of the low-pressure compressor, and a control unit that controls the exhaust gas flowrate adjustment unit such that the inter-compressor pressure ratio becomes a predetermined pressure ratio for optimizing an operation efficiency of the engine system.

An engine system comprises a fuel tank, an internal combustion engine, a generator, a recoil starter, a control unit, an injector, a fuel pump, an ignition apparatus, and a detection unit that detects a number-of-rotations of the internal combustion engine. The control unit, in a starting period of the internal combustion engine using the recoil starter, determines whether or not the internal combustion engine can perform self-sustaining rotation based on the number-of-rotations, and if the internal combustion engine cannot perform self-sustaining rotation. Electric power is not supplied to the ignition apparatus, the injector, and the fuel pump when the internal combustion engine cannot perform self-sustaining rotation. The electric power is supplied to them when the internal combustion engine can perform self-sustaining rotation.

An engine system comprises a fuel tank, an internal combustion engine, a generator, a recoil starter, a control unit, an injector, a fuel pump, an ignition apparatus, and a detection unit that detects a number-of-rotations of the internal combustion engine. The control unit, in a starting period of the internal combustion engine using the recoil starter, determines whether or not the internal combustion engine can perform self-sustaining rotation based on the number-of-rotations, and if the internal combustion engine cannot perform self-sustaining rotation. Electric power is not supplied to the ignition apparatus, the injector, and the fuel pump when the internal combustion engine cannot perform self-sustaining rotation. The electric power is supplied to them when the internal combustion engine can perform self-sustaining rotation.

A plant control system comprises a feedback controller 5 configured to determine a control input of a plant 6 so that one control output of the plant approaches a target value, a provisional target value calculating part 2 configured to calculate a provisional target value based on a predetermined parameter of the plant, and a reference governor 3 configured to perform a minimum value search of an object function by updating a corrected target value to thereby derive the target value from the provisional target value. The reference governor is configured to update the corrected target value only between r0.5R.sub.r and r. R.sub.r is a value of a partial differential for the corrected target value w of the object function when the corrected target value w is the provisional target value r.

A plant control system comprises a feedback controller 5 configured to determine a control input of a plant 6 so that one control output of the plant approaches a target value, a provisional target value calculating part 2 configured to calculate a provisional target value based on a predetermined parameter of the plant, and a reference governor 3 configured to perform a minimum value search of an object function by updating a corrected target value to thereby derive the target value from the provisional target value. The reference governor is configured to update the corrected target value only between r0.5R.sub.r and r. R.sub.r is a value of a partial differential for the corrected target value w of the object function when the corrected target value w is the provisional target value r.

An engine promoting DPF regeneration processing is provided. Catalyst activation processing and thereafter DPF regeneration processing are performed under control of a device. In the catalyst activation processing, a target temperature of exhaust at an exhaust exit of a catalyst is set to be in a first temperature region, and then the opening degree of an exhaust throttle device is controlled. In the DPF regeneration processing, the target temperature is set to be in a second temperature region. A target temperature of the exhaust at an exhaust inlet of a DPF is set to be in a third temperature region. The opening degree of the exhaust throttle device is controlled, and unburned fuel is supplied into the exhaust. The temperature regions are set to be successively higher, and a temperature difference between successive temperature regions is set to be successively lower.

An engine promoting DPF regeneration processing is provided. Catalyst activation processing and thereafter DPF regeneration processing are performed under control of a device. In the catalyst activation processing, a target temperature of exhaust at an exhaust exit of a catalyst is set to be in a first temperature region, and then the opening degree of an exhaust throttle device is controlled. In the DPF regeneration processing, the target temperature is set to be in a second temperature region. A target temperature of the exhaust at an exhaust inlet of a DPF is set to be in a third temperature region. The opening degree of the exhaust throttle device is controlled, and unburned fuel is supplied into the exhaust. The temperature regions are set to be successively higher, and a temperature difference between successive temperature regions is set to be successively lower.

A catalyst warm-up control method for a hybrid vehicle includes a battery supplying electric power to an electric motor, the battery is charged by an engine for electric power generation, and exhaust gas discharged from the engine 1 is treated by a catalyst. By the catalyst warm-up control method, when temperature of the catalyst is lower than required warm-up temperature for activating the catalyst, target revolution speed and target torque of the engine are controlled based on a state of charge of the battery, and, when target revolution speed is lower than lower-limit revolution speed at which the catalyst can be heated to the required warm-up temperature, the target revolution speed is controlled so as to be required warm-up revolution speed that is equal to or higher than the lower-limit revolution speed.

A catalyst warm-up control method for a hybrid vehicle includes a battery supplying electric power to an electric motor, the battery is charged by an engine for electric power generation, and exhaust gas discharged from the engine 1 is treated by a catalyst. By the catalyst warm-up control method, when temperature of the catalyst is lower than required warm-up temperature for activating the catalyst, target revolution speed and target torque of the engine are controlled based on a state of charge of the battery, and, when target revolution speed is lower than lower-limit revolution speed at which the catalyst can be heated to the required warm-up temperature, the target revolution speed is controlled so as to be required warm-up revolution speed that is equal to or higher than the lower-limit revolution speed.