CONTROL APPARATUS FOR AN ENGINE

• US 20140005912A1
• Filed: 03/22/2013
• Published: 01/02/2014
• Est. Priority Date: 06/29/2012
• Status: Active Grant

• Current Assignee: Mitsubishi Jidosha Kogyo Kabushiki Kaisha
• Original Assignee: Mitsubishi Jidosha Kogyo Kabushiki Kaisha
• Inventors: UEDA, Katsunori, MIYATA, Toshiyuki, IDE, Hideto
• Granted Patent: US 9,617,943 B2
• Time in Patent Office: Days
• US Class Current: 701/104
• CPC Class Codes: F02D 41/0042 Controlling the combustible mixture as a function of the canister purging, e.g. control of injected fuel to compensate for deviation of air fuel ratio when purging
• CPC Class Codes: F02D 41/0045 Estimating, calculating or determining the purging rate, amount, flow or concentration
• CPC Class Codes: F02D 41/1454 the characteristics being an oxygen content or concentration or the air-fuel ratio
• CPC Class Codes: F02D 41/3005 Details not otherwise provided for

Abstract

A control apparatus for an engine introduces purge gas containing fuel gas evaporated from a fuel tank into an intake system includes an air-fuel ratio calculation unit that calculates an air-fuel ratio (AF) of the engine, and a purge rate calculation unit that calculates a purge rate (R_PRG) corresponding to an introduction rate of the purge gas. The control apparatus further includes a concentration calculation unit that calculates a concentration (K_AF—PRG) of the purge gas based on the air-fuel ratio (AF) calculated by the air-fuel ratio calculation unit and the purge rate (R_PRG) calculated by the purge rate calculation unit. A decision unit permits or inhibits the concentration calculation unit to calculate the concentration (K_AF—PRG) based on the purge rate (R_PRG) calculated by the purge rate calculation unit. The estimation accuracy of the concentration (K_AF—PRG) of purge gas is improved.

Claims

1. A control apparatus for an engine that introduces purge gas containing fuel gas evaporated from a fuel tank into an intake system, comprising:

an air-fuel ratio calculation unit that calculates an air-fuel ratio (AF) of the engine;

a purge rate calculation unit that calculates a purge rate (R_PRG) corresponding to an introduction rate of the purge gas;

a concentration calculation unit that calculates a concentration (K<sub>AF—

PRG</sub>) of the purge gas based on the air-fuel ratio (AF) calculated by the air-fuel ratio calculation unit and the purge rate (R_PRG) calculated by the purge rate calculation unit; and

a decision unit that permits or inhibits the concentration calculation unit (4) to calculate the concentration (K<sub>AF—

PRG</sub>) based on the purge rate (R_PRG) calculated by the purge rate calculation unit.

2. The control apparatus according to claim 1, wherein

the decision unit allows the concentration calculation unit to update a calculation value of the concentration (K_AF—

_PRG) to the latest value when the purge rate (R_PRG) is equal to or higher than a criterion rate (R_TH); and

the decision unit makes the concentration calculation unit maintain the last value of the concentration (K<sub>AF—

PRG</sub>) when the purge rate (R_PRG) is lower than the criterion rate (R_TH).

3. The control apparatus according to claim 1, further comprising:

an air amount calculation unit that calculates an air amount (E_C) to be introduced into a cylinder of the engine; and

an inhibition period calculation unit that calculates a period for which the calculation of the concentration (K<sub>AF—

PRG</sub>) by the concentration calculation unit is inhibited based on a history of the air amount (E_C) calculated by the air amount calculation unit.

4. The control apparatus according to claim 2, further comprising:

an air amount calculation unit that calculates an air amount (E_C) to be introduced into a cylinder of the engine; and

an inhibition period calculation unit that calculates a period for which the calculation of the concentration (K<sub>AF—

PRG</sub>) by the concentration calculation unit is inhibited based on a history of the air amount (E_C) calculated by the air amount calculation unit.

5. The control apparatus according to claim 1, wherein

the decision unit permits or inhibits the calculation of the concentration (K_AF—

_PRG) to the concentration calculation unit based on a fuel amount correction coefficient (K<sub>FB—

PRG</sub>) correlative to a difference between the air-fuel ratio (AF) calculated by the air-fuel ratio calculation unit and a target air-fuel ratio.

6. The control apparatus according to claim 2, wherein

the decision unit permits or inhibits the calculation of the concentration (K_AF—

_PRG) to the concentration calculation unit based on a fuel amount correction coefficient (K<sub>FB—

PRG</sub>) correlative to a difference between the air-fuel ratio (AF) calculated by the air-fuel ratio calculation unit and a target air-fuel ratio.

7. The control apparatus according to claim 3, wherein

the decision unit permits or inhibits the calculation of the concentration (K_AF—

_PRG) to the concentration calculation unit based on a fuel amount correction coefficient (K<sub>FB—

PRG</sub>) correlative to a difference between the air-fuel ratio (AF) calculated by the air-fuel ratio calculation unit and a target air-fuel ratio.

8. The control apparatus according to claim 4, wherein

the decision unit permits or inhibits the calculation of the concentration (K_AF—

_PRG) to the concentration calculation unit based on a fuel amount correction coefficient (K<sub>FB—

PRG</sub>) correlative to a difference between the air-fuel ratio (AF) calculated by the air-fuel ratio calculation unit and a target air-fuel ratio.

9. The control apparatus according to claim 5, wherein

the decision unit

inhibits the calculation of the concentration (K_AF—

_PRG) in a driving state in which the variation amount of the fuel amount correction coefficient (K<sub>FB—

PRG</sub>) is equal to or greater than a criterion amount, and

permits the calculation of the concentration (K<sub>AF—

PRG</sub>) in another driving state in which the variation amount of the fuel amount correction coefficient (K<sub>FB—

PRG</sub>) is smaller than the criterion amount.

10. The control apparatus according to claim 6, wherein

the decision unit

inhibits the calculation of the concentration (K_AF—

_PRG) in a driving state in which the variation amount of the fuel amount correction coefficient (K<sub>FB—

PRG</sub>) is equal to or greater than a criterion amount, and

permits the calculation of the concentration (K<sub>AF—

PRG</sub>) in another driving state in which the variation amount of the fuel amount correction coefficient (K<sub>FB—

PRG</sub>) is smaller than the criterion amount.

11. The control apparatus according to claim 7, wherein

the decision unit

inhibits the calculation of the concentration (K_AF—

_PRG) in a driving state in which the variation amount of the fuel amount correction coefficient (K<sub>FB—

PRG</sub>) is equal to or greater than a criterion amount, and

permits the calculation of the concentration (K<sub>AF—

PRG</sub>) in another driving state in which the variation amount of the fuel amount correction coefficient (K<sub>FB—

PRG</sub>) is smaller than the criterion amount.

12. The control apparatus according to claim 8, wherein

the decision unit

inhibits the calculation of the concentration (K_AF—

_PRG) in a driving state in which the variation amount of the fuel amount correction coefficient (K<sub>FB—

PRG</sub>) is equal to or greater than a criterion amount, and

permits the calculation of the concentration (K<sub>AF—

PRG</sub>) in another driving state in which the variation amount of the fuel amount correction coefficient (K<sub>FB—

PRG</sub>) is smaller than the criterion amount.

13. The control apparatus according to claim 1, wherein

the decision unit

inhibits the calculation of the concentration (K_AF—

_PRG) when the engine is accelerated or decelerated suddenly, and

permits the calculation of the concentration (K<sub>AF—

PRG</sub>) except a case in which the engine is accelerated or decelerated suddenly.

14. The control apparatus according to claim 1, wherein

the decision unit

inhibits the calculation of the concentration (K_AF—

_PRG) when a load acting on the engine is equal to or lower than a criterion amount, and

permits the calculation of the concentration (K<sub>AF—

PRG</sub>) when the load is higher than the criterion amount.

15. The control apparatus according to claim 1, wherein

the decision unit

permits the calculation of the concentration (K_AF—

_PRG) when feedback injection control is being carried out, and

inhibits the calculation of the concentration (K<sub>AF—

PRG</sub>) when open loop injection control is being carried out.

16. The control apparatus according to claim 1, wherein

the decision unit changes a condition for permitting or inhibiting the calculation of the concentration (K_AF—

_PRG) in response to the air-fuel ratio (AF).