초록 ▼

A control system for an internal combustion engine includes a virtual engine model which mathematically represents the states of the engine in real time, but which is programmed to provide the engine's states at least a fraction of an engine cycle (and preferably at least one-fourth of an engine cyc

A control system for an internal combustion engine includes a virtual engine model which mathematically represents the states of the engine in real time, but which is programmed to provide the engine's states at least a fraction of an engine cycle (and preferably at least one-fourth of an engine cycle, i.e., one stroke) to several engine cycles in advance of the real engine. The mass flow entering and leaving the cylinder is modeled, allowing parameters such as the mass of air per cylinder (MAC) and residual exhaust gas to be computed, and thereafter used to generate engine control commands related to fuel injection (air/fuel ratio), spark advance, and so forth.

대표청구항 ▼

What is claimed is: 1. A control system for a multi-cylinder internal combustion engine, wherein for each cylinder: a. the control system calculates estimates of: (1) the mass inputs entering the cylinder, the mass inputs including intake air, (2) the mass within the cylinder, and (3) the mass outp

What is claimed is: 1. A control system for a multi-cylinder internal combustion engine, wherein for each cylinder: a. the control system calculates estimates of: (1) the mass inputs entering the cylinder, the mass inputs including intake air, (2) the mass within the cylinder, and (3) the mass outputs exiting the cylinder, the mass outputs including exhaust gas, at least a fraction of an engine cycle in the future; and b. the control system supplies fuel to the cylinder in accordance with the estimated mass within the cylinder. 2. The control system of claim 1 wherein the control system also supplies an igniting spark to each cylinder, wherein the timing of the spark for each cylinder is independent of the timing of the spark for at least some of the other cylinders. 3. The control system of claim 2 wherein the timing of the spark supplied to each cylinder is dependent on the estimated mass within the cylinder. 4. The control system of claim 1 wherein during each engine cycle: a. the control system receives a measurement of the air actually supplied to all cylinders collectively; b. the control system calculates an estimate of the air supplied to all cylinders collectively; and c. the control system adapts its calculations to reduce the difference between the estimate of the air supplied to all cylinders and the measurement of the air actually supplied to all cylinders collectively. 5. The control system of claim 1 wherein: a. the calculated estimates of the mass entering, exiting, and within each cylinder are calculated within a virtual engine model which simulates the operation of the engine at least a fraction of an engine cycle in the future, and b. the virtual engine model also calculates estimates of the energy entering, exiting, and within each cylinder. 6. The control system of claim 5 wherein the virtual engine model calculates the estimated mass within each cylinder between 0.1 and 4 cycles in advance of the engine's present cycle. 7. The control system of claim 5 wherein the virtual engine model models the intake air as being: a. compressible, and b. variable in only one dimension. 8. The control system of claim 1 wherein the estimate of the mass within the cylinder includes an estimate of the residual exhaust gas retained within each cylinder from any prior engine cycles. 9. The control system of claim 8 wherein the control system also supplies an igniting spark to each cylinder, the timing of the spark for each cylinder is dependent on the cylinder's estimated residual exhaust gas. 10. The control system of claim 8 wherein: a. each cylinder includes at least one intake valve and at least one exhaust valve; and b. the control system alters the actuation of at least one of the intake and exhaust valves for each cylinder in dependence on the cylinder's estimated residual exhaust gas. 11. The control system of claim 1 wherein each cylinder includes at least one intake valve and at least one exhaust valve, at least one of these valves having a valve lift profile which varies depending on at least one of: a. engine speed, and b. engine load. 12. A control system for a multi-cylinder internal combustion engine wherein each cylinder includes: (1) at least one intake valve supplying the cylinder with air from an intake system during an engine cycle; (2) at least one fuel injector supplying the cylinder with fuel during the engine cycle; and (3) at least one exhaust valve supplying exhaust gas from the cylinder to an exhaust system during the engine cycle, wherein the control system includes, for each cylinder, a virtual engine model which: a. calculates, during each engine cycle, an estimation of the contents of the cylinder at least a fraction of an engine cycle in the future; and b. actuates the fuel injector in accordance with the estimated cylinder contents. 13. The control system of claim 12 wherein the virtual engine model calculates the estimated air charge for each cylinder between 0.1 and 4 cycles in advance of the engine's present cycle. 14. The control system of claim 12 wherein the estimated air charge calculations performed by the virtual engine model assume that air flow from the intake system to each cylinder: a. is compressible, and b. is only variable in one dimension. 15. The control system of claim 12 wherein each cylinder's virtual engine model also calculates, during each engine cycle, an estimation of the exhaust gas exiting the cylinder when the cylinder's exhaust valve is open. 16. The control system of claim 15 wherein each cylinder's virtual engine model also calculates, during each engine cycle, an estimation of the exhaust gas exiting the cylinder at least a fraction of an engine cycle in the future. 17. The control system of claim 16 wherein the calculation of the estimated contents of the cylinder includes a calculation of the estimated residual exhaust gas retained within each cylinder after the cylinder's exhaust valve is closed. 18. The control system of claim 17 wherein the control system also controls the supply of an igniting spark to each cylinder, the timing of each cylinder's spark being dependent on: a. the cylinder's estimated air charge, and b. the cylinder's estimated residual exhaust gas. 19. The control system of claim 17 wherein the control system alters the actuation of at least one of the intake and exhaust valves for each cylinder in dependence on the cylinder's estimated residual exhaust gas. 20. The control system of claim 12 wherein: a. the virtual engine model receives measurements of the air being supplied to the engine during the engine cycle; b. the virtual engine model also calculates an estimate of the air being supplied to all cylinders during the engine cycle; and c. the virtual engine model is at least periodically modified to reduce the difference between the estimated air being supplied to all cylinders and the measured air being supplied to the engine. 21. The control system of claim 12 wherein the control system also controls the supply of an igniting spark to each cylinder, the timing of each cylinder's spark being dependent on that cylinder's estimated air charge. 22. The control system of claim 12 wherein the engine has a valve lift profile which varies depending on at least one of: a. engine speed, and b. engine load. 23. The control system of claim 12 wherein: a. the engine includes an adjustable throttle which meters the air supplied to the intake system; b. the measurement of the air supplied to the cylinders includes a measured intake system pressure; c. the control system also calculates an estimated intake system pressure for the cylinders; and d. the throttle is at least periodically adjusted to reduce the difference between the estimated intake system pressure and the measured intake system pressure. 24. A control system for a multi-cylinder internal combustion engine wherein each cylinder includes: (1) at least one intake valve supplying the cylinder with air from an intake system during an engine cycle, and (2) at least one exhaust valve supplying exhaust gas from the cylinder to an exhaust system during the engine cycle, wherein the control system: a. receives measurements of the air supplied to the cylinders during the engine cycle; b. calculates for each cylinder, in advance of the closing of the cylinder's intake valve, an estimated air charge that will be contained in the cylinder upon such closing; and c controls the supply of fuel to each cylinder in accordance with that cylinder's estimated air charge.