초록 ▼

An internal combustion engine control apparatus that prevents an abrupt change in the air amount at the time of supercharger switching. The control apparatus enters a small turbo operating state in which a small turbocharger is mainly operative, during relatively low-rotation-speed and low-load side

An internal combustion engine control apparatus that prevents an abrupt change in the air amount at the time of supercharger switching. The control apparatus enters a small turbo operating state in which a small turbocharger is mainly operative, during relatively low-rotation-speed and low-load side, and enters a large turbo operating state in which a large turbocharger is mainly operative, in a relatively high-rotation-speed and high-load. In the small turbo operating state, the control apparatus can exercise charging efficiency enhancement control by using a scavenging effect. Before switching from the small turbo operating state to the large turbo operating state, the control apparatus predicts whether the large turbocharger will build up its boost pressure quickly or slowly. When slow boost pressure is predicted, the control apparatus exercises charging efficiency enhancement control to provide a low degree of charging efficiency enhancement.

대표청구항 ▼

1. A control apparatus for an internal combustion engine, the control apparatus comprising: a supercharger;supercharger switching means for switching the supercharger between a supercharger nonoperating state and a supercharger operating state, the nonoperating state making the supercharger substant

1. A control apparatus for an internal combustion engine, the control apparatus comprising: a supercharger;supercharger switching means for switching the supercharger between a supercharger nonoperating state and a supercharger operating state, the nonoperating state making the supercharger substantially inoperative when an operating point of the internal combustion engine is within a low-rotation-speed and low-load region, the operating state making the supercharger operative when the operating point is within a high-rotation-speed and high-load region;charging efficiency enhancement means for exercising charging efficiency enhancement control in the supercharger nonoperating state, wherein a valve overlap period is provided during which an intake valve open period and an exhaust valve open period overlap and a trough of exhaust pressure pulsation is adjusted to be present within the valve overlap period;boost pressure prediction means for preliminarily predicting, before switching from the supercharger nonoperating state to the supercharger operating state, whether the supercharger will build up boost pressure quickly or slowly depending on the rotation speed of the supercharger; anddegree-of-charging-efficiency-enhancement control means which, when the boost pressure is predicted to build up slowly, causes the charging efficiency enhancement means to provide a lower degree of charging efficiency enhancement than when the boost pressure is predicted to build up quickly. 2. The control apparatus according to claim 1, further comprising degree-of-warm-up detection means for detecting the degree of warm-up of the internal combustion engine, wherein the boost pressure prediction means predicts, based on the degree of warm-up, whether the boost pressure will build up quickly or slowly. 3. The control apparatus according to claim 1, further comprising switching point correction means which, when the degree of charging efficiency enhancement is high, set a switching point of the supercharger switching means on a higher-rotation-speed and higher-load side than when the degree of charging efficiency enhancement is low. 4. A control apparatus for an internal combustion engine, the control apparatus comprising: a small supercharger;a large supercharger having a larger capacity than the small supercharger;supercharger switching means for switching these superchargers between a small supercharger operating state and a large supercharger operating state, the small supercharger operating state making the small supercharger mainly operative when an operating point of the internal combustion engine is within a low-rotation-speed and low-load region, the large supercharger operating state making the large supercharger mainly operative when the operating point is within a high-rotation-speed and high-load region;charging efficiency enhancement means for exercising charging efficiency enhancement control in the small supercharger operating state, wherein a valve overlap period is provided during which an intake valve open period and an exhaust valve open period overlap and a trough of exhaust pressure pulsation is adjusted to be present within the valve overlap period;boost pressure prediction means for preliminarily predicting, before switching from the small supercharger operating state to the large supercharger operating state, whether the large supercharger will build up boost pressure quickly or slowly depending on the rotation speed of the large supercharger; anddegree-of-charging-efficiency-enhancement control means which, when the boost pressure is predicted to build up slowly, causes the charging efficiency enhancement means to provide a lower degree of charging efficiency enhancement than when the boost pressure is predicted to build up quickly. 5. The control apparatus according to claim 4, wherein the large supercharger includes a turbine which operates on exhaust gas, and a variable nozzle which varies the inlet area of the turbine, and wherein the boost pressure prediction means predicts, based on the opening of the variable nozzle, whether the boost pressure will build up quickly or slowly. 6. The control apparatus according to claim 4, further comprising detection means for detecting the boost pressure or the rotation speed of the large supercharger, wherein the boost pressure prediction means predicts, based on the detected boost pressure or rotation speed, whether the boost pressure will build up quickly or slowly. 7. The control apparatus according to claim 4, further comprising degree-of-warm-up detection means for detecting the degree of warm-up of the internal combustion engine, wherein the boost pressure prediction means predicts, based on the degree of warm-up, whether the boost pressure will build up quickly or slowly. 8. The control apparatus according to claim 4, further comprising switching point correction means which, when the degree of charging efficiency enhancement is high, set a switching point of the supercharger switching means on a higher-rotation-speed and higher-load side than when the degree of charging efficiency enhancement is low. 9. A control apparatus for an internal combustion engine, the control apparatus comprising: a supercharger;a supercharger switching device for switching the supercharger between a supercharger nonoperating state and a supercharger operating state, the nonoperating state making the supercharger substantially inoperative when an operating point of the internal combustion engine is within a low-rotation-speed and low-load region, the operating state making the supercharger operative when the operating point is within a high-rotation-speed and high-load region;a charging efficiency enhancement device for exercising charging efficiency enhancement control in the supercharger nonoperating state, wherein a valve overlap period is provided during which an intake valve open period and an exhaust valve open period overlap and a trough of exhaust pressure pulsation is adjusted to be present within the valve overlap period;a boost pressure prediction device for preliminarily predicting, before switching from the supercharger nonoperating state to the supercharger operating state, whether the supercharger will build up boost pressure quickly or slowly depending on the rotation speed of the supercharger; anda degree-of-charging-efficiency-enhancement control device which, when the boost pressure is predicted to build up slowly, causes the charging efficiency enhancement device to provide a lower degree of charging efficiency enhancement than when the boost pressure is predicted to build up quickly. 10. The control apparatus according to claim 9, further comprising a degree-of-warm-up detection device for detecting the degree of warm-up of the internal combustion engine, wherein the boost pressure prediction device predicts, based on the degree of warm-up, whether the boost pressure will build up quickly or slowly. 11. The control apparatus according to claim 9, further comprising a switching point correction device which, when the degree of charging efficiency enhancement is high, set a switching point of the supercharger switching device on a higher-rotation-speed and higher-load side than when the degree of charging efficiency enhancement is low. 12. A control apparatus for an internal combustion engine, the control apparatus comprising: a small supercharger;a large supercharger having a larger capacity than the small supercharger;a supercharger switching device for switching these superchargers between a small supercharger operating state and a large supercharger operating state, the small supercharger operating state making the small supercharger mainly operative when an operating point of the internal combustion engine is within a low-rotation-speed and low-load region, the large supercharger operating state making the large supercharger mainly operative when the operating point is within a high-rotation-speed and high-load region;a charging efficiency enhancement device for exercising charging efficiency enhancement control in the small supercharger operating state, wherein a valve overlap period is provided during which an intake valve open period and an exhaust valve open period overlap and a trough of exhaust pressure pulsation is adjusted to be present within the valve overlap period;a boost pressure prediction device for preliminarily predicting, before switching from the small supercharger operating state to the large supercharger operating state, whether the large supercharger will build up boost pressure quickly or slowly depending on the rotation speed of the large supercharger; anda degree-of-charging-efficiency-enhancement control device which, when the boost pressure is predicted to build up slowly, causes the charging efficiency enhancement device to provide a lower degree of charging efficiency enhancement than when the boost pressure is predicted to build up quickly. 13. The control apparatus according to claim 12, wherein the large supercharger includes a turbine which operates on exhaust gas, and a variable nozzle which varies the inlet area of the turbine, and wherein the boost pressure prediction device predicts, based on the opening of the variable nozzle, whether the boost pressure will build up quickly or slowly. 14. The control apparatus according to claim 12, further comprising a detection device for detecting the boost pressure or the rotation speed of the large supercharger, wherein the boost pressure prediction device predicts, based on the detected boost pressure or rotation speed, whether the boost pressure will build up quickly or slowly. 15. The control apparatus according to claim 12, further comprising a degree-of-warm-up detection device for detecting the degree of warm-up of the internal combustion engine, wherein the boost pressure prediction device predicts, based on the degree of warm-up, whether the boost pressure will build up quickly or slowly. 16. The control apparatus according to claim 12, further comprising a switching point correction device which, when the degree of charging efficiency enhancement is high, set a switching point of the supercharger switching device on a higher-rotation-speed and higher-load side than when the degree of charging efficiency enhancement is low.