Control method and apparatus for internal combustion engine

Claim 2

A control apparatus for an internal combustion engine comprising: a fuel tank (13); a first and a second evaporative fuel path (16, 15) for passing evaporative fuel from said fuel tank (13) to an air intake path (7); a first and a second control valve (6, 5) pro­vided in said first and second evaporative fuel routes (6, 5) for controlling the quantity of evaporative fuel pass­ing therethrough; first control quantity determination means (410, 412) for determining a first control quantity for con­trolling said first control valve (6) on the basis of the state of operating the engine; and second control quantity determination means (126 to 132) for determining a second control quantity for con­trolling said second control valve (5) on the basis of said first control quantity.

Claim 3

A control apparatus for an internal combustion engine according to claim 1, further comprising: a canister (14) for storing evaporative emission of the fuel in the fuel tank (13); said first and second evaporative fuel paths comprising an evaporative fuel path for passing the eva­ porative fuel from said canister to an air intake path of the engine; said second control valve (6) is provided in said evaporative fuel path from said canister for con­trolling an amount of the evaporative fuel passing there­through from said canister; and said second control quantity determination means include control means (10) for generating a second control signal for controlling said second control valve (5) on the basis of a state of operation of said first control valve (6).

Claim 4

A control apparatus for an internal combustion engine according to Claim 2, wherein said second control quantity determination means (128, 120) determine that said second control quantity is reduced when said first control quantity has increased.

Claim 5

A control apparatus for an internal combustion engine according to Claim 2, wherein said second control quantity determination means determine that said control quantity is increased (714) when said first control quan­tity has increased (618).

Claim 6

A control apparatus for an internal combustion engine according to Claim 2, wherein said second control quantity determination means determine that said second control quantity is reduced (712) when said first control quantity has reduced (616).

Claim 7

A control apparatus for an internal combustion engine according to Claim 2, wherein said second control quantity determination means (102, 124) determine a second control quantity which makes the second control valve means to be closed when the engine is not operating.

Claim 8

A control apparatus for an internal combustion engine according to Claim 2, wherein said second control quantity determination means (104, 124) determine a second control quantity which makes the second control valve means to be closed when a fuel supply quantity is not being feedback-controlled so as to make an air-fuel ratio to be a target value.

Claim 9

A control apparatus for an internal combustion engine according to Claim 2, wherein said second control quantity determination means determine (108, 124) a second control quantity which make said second control valve means to be closed when a fuel supply is being cut.

Claim 10

A control apparatus for an internal combustion engine according to one of the preceding claims, wherein valve state determination means (410, 412) are provided for determining whether said first control valve is to be in an open state or a closed state, in accordance with an operating state of the engine; said control quantity determination means (126 to 132) are determining the control quantity of the se­cond control valve in accordance with the open or closed state of said first control valve as determined by said valve state determination means.

Claim 11

A control apparatus for an internal combustion engine according to Claim 9, wherein said control quanti­ty determination means (128 to 130) reduce said control quantity to a predetermined quantity when said first control valve (6) has changed from a closed state to an open state.

Claim 12

A control apparatus for an internal combustion engine according to Claim 9, wherein said predetermined quantity is preset (130) to a value at which said second control valve (5) is closed.

Claim 13

A control apparatus for an internal combustion engine according to Claim 9, wherein said control quantity determination means (130, 132) gradually increase said control quantity after it has been reduced to a predetermined quantity.

Claim 14

A control apparatus for an internal combustion engine according to Claim 9, wherein said control quantity determination means (126, 132) increase said control quantity when said first control valve has changed from an open state to a closed state.

Claim 15

A control apparatus for an internal combustion engine according to Claim 9, wherein said control quantity determination means (116) determine a control quantity of the second control valve on the basis of an engine speed or an engine load.

Claim 16

A control method for an internal combustion engine comprising: a fuel tank (13); a first and a second evaporative fuel routes (16, 15) for passing evaporative fuel from said fuel tank (13) to an air intake path; a first and a second control valve (6, 5) provided in said first and second evaporative fuel routes (16, 15) for controlling an amount of the evaporative fuel passing therethrough; a first control quantity determination means (620) for determining a control quantity of the first control valve on the basis of a state of the engine; and a second control quantity determination means (716) for determining a control quantity of the second control valve on the basis of a state of the engine, said method comprising the steps of: controlling (410, 412) said first control valve (6) on the basis of an operation state of the engine; and obtaining (126 to 132) a control quantity for controlling said second control valve (5) on the basis of said first control quantity.

Claim 17

A control method for an internal combustion engine comprising: a fuel tank (13); a first and a second evaporative fuel routes (16, 15) for passing evaporative fuel from said fuel tank (13) to an air intake path; a first and a second control valve (6, 5) provided in said first and second evaporative fuel routes (16, 15) for controlling an amount of the evaporative fuel passing therethrough; a first control quantity determination means (620) for determining a control quantity of the first control valve on the basis of a state of the engine; and a second control quantity determination means (716) for determining a control quantity of the second control valve on the basis of a state of the engine, said method comprising the steps of: controlling (410, 412) said first control valve (6) on the basis of an operation state of the engine; and obtaining (126 to 132) a control quantity for controlling said second control valve (5) on the basis of said first control quantity.

Claim 18

The method according to Claim 15, said method further comprising the steps of: obtaining (410, 412) opening and closing of said first control valve (6) based on an operating state of the engine; and obtaining (126 to 132) a control quantity of said second control valve (5) on the basis of a control state of said first control valve (6).

Claim 19

A control apparatus for an internal combustion engine according to Claim 3, wherein said second control quantity is increased (618, 708) when a supply of a fuel is necessary.

Claim 20

A control apparatus for an internal combustion engine according to Claim 4, wherein said second control quantity is reduced (610, 706) when an air-fuel ratio is out of a predetermined state.

Claim 21

A control apparatus for an internal combustion engine according to Claim 1, wherein said second control quantity determination means (126, 132) increase said second control quantity when said first control quantity has reduced.