Apparatus of estimating fuel injection state

1. An apparatus of estimating fuel injection state of a fuel injection system having at least three injectors including a first, second and third injectors provided for a first, second and third cylinders of an internal combustion engine respectively, a first fuel pressure sensor which detects pressure of fuel supplied to the first injector, and a second fuel pressure sensor which detects pressure of fuel supplied to the second injector, the apparatus comprising:

a first acquisition section which acquires an injected cylinder waveform, the injected cylinder waveform being shown by fuel pressure change detected by the first fuel pressure sensor when the first injector injects fuel; a second acquisition section which acquires a first non-injected cylinder waveform, the first non-injected cylinder waveform being shown by fuel pressure change detected by the second fuel pressure sensor when the first injector injects fuel;

a correlation calculation section which calculates a correlation between the injected cylinder waveform and the first non-injected cylinder waveform;

a third acquisition section which acquires a second non-injected cylinder waveform, the second non-injected cylinder waveform being shown by fuel pressure change detected by the first or second fuel pressure sensor when the third injector injects fuel;

an injection state estimation section which estimates fuel injection state injected from the third injector based on the second non-injected cylinder waveform and the correlation;

an injection delay calculation section which calculates a first injection delay time showing a response delay of injection state with respect to an injection start command signal to the first injector based on the injected cylinder waveform;

a first drop delay calculation section which calculates a first drop delay time until the first non-injected cylinder waveform begins dropping from the injection start command signal to the first injector; and

a second drop delay calculation section which calculates a second drop delay time until the second non-injected cylinder waveform begins dropping from the injection start command signal to the third injector, wherein

the correlation calculation section calculates the correlation between the first injection delay time and the first drop delay time, and wherein

the injection state estimation section estimates a second injection delay time as the fuel injection state based on the second drop delay time and the correlation, the second injection delay time showing a response delay of injection state of the third injector with respect to an injection start command signal to the third injector.

2. The apparatus of estimating fuel injection state in claim 1 , further comprising:

an injected waveform change calculation section which calculates a waveform change amount of the injected cylinder, the waveform change amount of the injected cylinder being shown by an amount of injected fuel from the first injector calculated based on the injected cylinder waveform, an integrated value of the injected cylinder waveform, or a pressure drop amount of the injected cylinder waveform;

a first non-injected waveform change calculation section which calculates a first waveform change amount of the non-injected cylinder, the first waveform change amount of the non-injected cylinder being shown by an integrated value of the non-injected cylinder waveform, or a pressure drop amount of the non-injected cylinder waveform; and

a second non-injected waveform change calculation section which calculates a second waveform change amount of the non-injected cylinder when the third injector injects fuel, the second waveform change amount of the non-injected cylinder being shown by an integrated value of the second non-injected cylinder waveform, or a pressure drop amount of the second non-injected cylinder waveform, wherein

the correlation calculation section calculates the correlation between the waveform change amount of the injected cylinder and the first waveform change amount of the non-injected cylinder, and wherein

the injection state estimation section estimates an amount of injected fuel from the third injector based on the second waveform change amount of the non-injected cylinder and the correlation.

3. The apparatus of estimating fuel injection state in claim 2 , further comprising:

a drop start timing calculation section which calculates a start timing of pressure drop in the first non-injected cylinder waveform caused by fuel injection from the first injector, wherein

the first and second non-injected waveform change calculation section calculates the integrated value of the non-injected cylinder waveform as the first and second waveform change amount of the non-injected cylinder, and calculates the integrated value by integrating the non-injected cylinder waveform over an integration window, the integration window being defined with a start timing which is obtained by the start timing of pressure drop.

4. The apparatus of estimating fuel injection state in claim 2 , further comprising:

a drop delay time calculation section which calculates a drop delay time until a start timing of pressure drop appears on the first non-injected cylinder waveform from an injection start command signal to the first injector, wherein

the first and second non-injected waveform change calculation section calculates the integrated value of the non-injected cylinder waveform as the first and second waveform change amount of the non-injected cylinder, and calculates the integrated value by integrating the non-injected cylinder waveform over an integration window, the integration window being defined with a finish timing which is obtained by a timing when the drop delay time is elapsed from an injection finish command signal to the first injector.

5. The apparatus of estimating fuel injection state in claim 1 , wherein

the fuel injection system further includes a fuel pump and a pressurized fuel container which are configured to accumulate fuel pressurized by the fuel pump in the pressurized fuel container, and to deliver pressurized fuel from the pressurized fuel container to the first, second and third injectors, and wherein

the correlation calculation section distinguishes and calculates the correlation in a distinguishable manner depending on whether the injected cylinder waveform and the first and second non-injected cylinder waveform are detected in a pressurizing period or in a non-pressurizing period of the fuel pump, and wherein

the injection state estimation section selects the correlation to be used for estimation of the fuel injection state, according to whether the second non-injected cylinder waveform is detected at the pressurizing period or in the non-pressurizing period of the fuel pump.

6. The apparatus of estimating fuel injection state in claim 1 , further comprising:

a storage section which stores the correlation calculated by the correlation calculation section in a map in a manner that the correlation is associated with pressure just before the injected cylinder waveform starts dropping, wherein

the correlation calculation section obtains the correlation to be used for the estimation based on pressure just before the second non-injected cylinder waveform starts dropping and the map.

7. The apparatus of estimating fuel injection state in claim 1 , wherein

the fuel injection system further includes a fuel pump and a pressurized fuel container which are configured to accumulate fuel pressurized by the fuel pump in the pressurized fuel container, and to deliver pressurized fuel from the pressurized fuel container to the first, second and third injectors, and wherein

the first fuel pressure sensor is disposed on a fuel passage from an outlet of the pressurized fuel container to a nozzle hole of the first injector.

8. An apparatus of estimating fuel injection state of a fuel injection system having at least three injectors including a first, second and third injectors provided for a first, second and third cylinders of an internal combustion engine respectively, a first fuel pressure sensor which detects pressure of fuel supplied to the first injector, and a second fuel pressure sensor which detects pressure of fuel supplied to the second injector, the apparatus comprising:

a first acquisition section which acquires an injected cylinder waveform, the injected cylinder waveform being shown by fuel pressure change detected by the first fuel pressure sensor when the first injector injects fuel; a second acquisition section which acquires a first non-injected cylinder waveform, the first non-injected cylinder waveform being shown by fuel pressure change detected by the second fuel pressure sensor when the first injector injects fuel;

a correlation calculation section which calculates a correlation between the injected cylinder waveform and the first non-injected cylinder waveform;

a third acquisition section which acquires a second non-injected cylinder waveform, the second non-injected cylinder waveform being shown by fuel pressure change detected by the first or second fuel pressure sensor when the third injector injects fuel;

an injection state estimation section which estimates fuel injection state injected from the third injector based on the second non-injected cylinder waveform and the correlation;

an injected waveform change calculation section which calculates a waveform change amount of the injected cylinder, the waveform change amount of the injected cylinder being shown by an amount of injected fuel from the first injector calculated based on the injected cylinder waveform, an integrated value of the injected cylinder waveform, or a pressure drop amount of the injected cylinder waveform;

a first non-injected waveform change calculation section which calculates a first waveform change amount of the non-injected cylinder, the first waveform change amount of the non-injected cylinder being shown by an integrated value of the non-injected cylinder waveform, or a pressure drop amount of the non-injected cylinder waveform; and

a second non-injected waveform change calculation section which calculates a second waveform change amount of the non-injected cylinder when the third injector injects fuel, the second waveform change amount of the non-injected cylinder being shown by an integrated value of the second non-injected cylinder waveform, or a pressure drop amount of the second non-injected cylinder waveform, wherein

the correlation calculation section calculates the correlation between the waveform change amount of the injected cylinder and the first waveform change amount of the non-injected cylinder, and wherein

the injection state estimation section estimates an amount of injected fuel from the third injector based on the second waveform change amount of the non-injected cylinder and the correlation.

9. The apparatus of estimating fuel injection state in claim 8 , further comprising:

a drop start timing calculation section which calculates a start timing of pressure drop in the first non-injected cylinder waveform caused by fuel injection from the first injector, wherein

the first and second non-injected waveform change calculation section calculates the integrated value of the non-injected cylinder waveform as the first and second waveform change amount of the non-injected cylinder, and calculates the integrated value by integrating the non-injected cylinder waveform over an integration window, the integration window being defined with a start timing which is obtained by the start timing of pressure drop.

10. The apparatus of estimating fuel injection state in claim 8 , further comprising:

a drop delay time calculation section which calculates a drop delay time until a start timing of pressure drop appears on the first non-injected cylinder waveform from an injection start command signal to the first injector, wherein

the first and second non-injected waveform change calculation section calculates the integrated value of the non-injected cylinder waveform as the first and second waveform change amount of the non-injected cylinder, and calculates the integrated value by integrating the non-injected cylinder waveform over an integration window, the integration window being defined with a finish timing which is obtained by a timing when the drop delay time is elapsed from an injection finish command signal to the first injector.

11. The apparatus of estimating fuel injection state in claim 8 , wherein

the fuel injection system further includes a fuel pump and a pressurized fuel container which are configured to accumulate fuel pressurized by the fuel pump in the pressurized fuel container, and to deliver pressurized fuel from the pressurized fuel container to the first, second and third injectors, and wherein

the correlation calculation section distinguishes and calculates the correlation in a distinguishable manner depending on whether the injected cylinder waveform and the first and second non-injected cylinder waveform are detected in a pressurizing period or in a non-pressurizing period of the fuel pump, and wherein

the injection state estimation section selects the correlation to be used for estimation of the fuel injection state, according to whether the second non-injected cylinder waveform is detected at the pressurizing period or in the non-pressurizing period of the fuel pump.

12. The apparatus of estimating fuel injection state in claim 8 , further comprising:

a storage section which stores the correlation calculated by the correlation calculation section in a map in a manner that the correlation is associated with pressure just before the injected cylinder waveform starts dropping, wherein

the correlation calculation section obtains the correlation to be used for the estimation based on pressure just before the second non-injected cylinder waveform starts dropping and the map.

13. The apparatus of estimating fuel injection state in claim 8 , wherein

the fuel injection system further includes a fuel pump and a pressurized fuel container which are configured to accumulate fuel pressurized by the fuel pump in the pressurized fuel container, and to deliver pressurized fuel from the pressurized fuel container to the first, second and third injectors, and wherein

the first fuel pressure sensor is disposed on a fuel passage from an outlet of the pressurized fuel container to a nozzle hole of the first injector.