Engine control device

1. An engine control device for controlling an engine including a combustion chamber, an intake passage, and an exhaust passage, the engine control device comprising:

a dynamo-electric machine configured to generate electric power by rotation of the engine;

a battery configured to store the electric power generated by the dynamo-electric machine;

an electric supercharger including an electric compressor disposed in the intake passage and configured to supercharge intake air into the combustion chamber by the electric power stored in the battery;

a mechanical supercharger including an exhaust turbine disposed in the exhaust passage and configured to be driven by exhaust gas in the exhaust passage, and a mechanical compressor disposed in the intake passage and configured to supercharge intake air into the combustion chamber;

a remaining charge detector configured to detect a remaining amount of charge of the battery; and

a supercharge controller configured to adjust a ratio between a supercharging pressure by the electric supercharger and a supercharging pressure by the mechanical supercharger according to the remaining amount of charge of the battery,

wherein the supercharge controller is configured to determine a degree of opening of a exhaust bypass valve based on a difference between a target supercharging pressure of intake air and the supercharging pressure by the electric supercharger.

2. The engine control device of claim 1 , wherein the engine further includes an exhaust bypass passage connecting portions of the exhaust passage upstream and downstream of the exhaust turbine, and an exhaust bypass valve configured to selectively open and close the exhaust bypass passage, the supercharge controller being configured to control a degree of opening of the exhaust bypass valve according to the remaining amount of charge of the battery.

3. The engine control device of claim 1 , wherein the supercharge controller is configured to reduce the supercharging pressure by the electric supercharger and increase the supercharging pressure by the mechanical supercharger when the remaining amount of charge of the battery falls below a predetermined amount of charge while the electric supercharger is being activated.

4. The engine control device of claim 1 , further comprising an operating state controller configured to control a revolving speed of the engine and a load of the engine with reference to an equi-output curve where an output of the engine does not change, while the ratio between the supercharging pressure by the electric supercharger and the supercharging pressure by the mechanical supercharger is changing.

5. A vehicle comprising:

the engine control device of claim 4 ;

an engine configured to be controlled by the engine control device; and

a transmission configured to change a speed reduction ratio of the output of the engine,

wherein the operating state controller is configured to control the speed reduction ratio as the revolving speed of the engine and the load of the engine change along the equi-output curve.

6. The engine control device of claim 2 , wherein the supercharge controller is configured to reduce the supercharging pressure by the electric supercharger and increase the supercharging pressure by the mechanical supercharger when the remaining amount of charge of the battery falls below a predetermined amount of charge while the electric supercharger is being activated.

7. The engine control device of claim 2 , further comprising an operating state controller configured to control a revolving speed of the engine and a load of the engine with reference to an equi-output curve where an output of the engine does not change, while the ratio between the supercharging pressure by the electric supercharger and the supercharging pressure by the mechanical supercharger is changing.

8. A vehicle comprising:

the engine control device of claim 7 ;

an engine configured to be controlled by the engine control device; and

a transmission configured to change a speed reduction ratio of the output of the engine,

wherein the operating state controller is configured to control the speed reduction ratio as the revolving speed of the engine and the load of the engine change along the equi-output curve.

9. The engine control device of claim 3 , further comprising an operating state controller configured to control a revolving speed of the engine and a load of the engine with reference to an equi-output curve where an output of the engine does not change, while the ratio between the supercharging pressure by the electric supercharger and the supercharging pressure by the mechanical supercharger is changing.

10. A vehicle comprising:

the engine control device of claim 9 ;

an engine configured to be controlled by the engine control device; and

a transmission configured to change a speed reduction ratio of the output of the engine,

wherein the operating state controller is configured to control the speed reduction ratio as the revolving speed of the engine and the load of the engine change along the equi-output curve.

11. The engine control device of claim 6 , further comprising an operating state controller configured to control a revolving speed of the engine and a load of the engine with reference to an equi-output curve where an output of the engine does not change, while the ratio between the supercharging pressure by the electric supercharger and the supercharging pressure by the mechanical supercharger is changing.

12. A vehicle comprising:

the engine control device of claim 11 ;

an engine configured to be controlled by the engine control device; and

a transmission configured to change a speed reduction ratio of the output of the engine,

wherein the operating state controller is configured to control the speed reduction ratio as the revolving speed of the engine and the load of the engine change along the equi-output curve.