Fuel injection control system for internal combustion engine with fuel cut-off control at high engine speed range suppressive of recovery shock upon fuels resumption

Claim 2

A fuel injection control system for an internal combustion engine, for performing fuel cut-off operation for blocking fuel delivery in response to an excessively high engine speed over a predetermined high engine speed criterion for protecting the engine, comprising: a fuel injection system including a fuel injection valve for delivering a controlled amount of fuel at a controlled timing; a sensor means for monitoring engine driving condition parameters including an engine revolution speed; and a controller, associated with said fuel injection system for controlling fuel delivery amount and fuel injection timing based on the engine driving parameters monitored by said sensor means, said controller being responsive to the engine revolution speed higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined high engine speed criterion, to initiate fuel cut-off operation to intermittently block fuel delivery through said fuel injection valve.

Claim 3

A fuel injection control system as set forth in claim 1, wherein said controller derives ratio of fuel delivery blocking period and fuel delivery permitting period on the basis of magnitude of engine speed in excess of said predetermined fuel cut speed.

Claim 4

A fuel injection control system as set forth in claim 2, wherein said controller derives a period of a fuel cut cycle, which fuel cut cycle period being variable depending upon the excess magnitude of the engine speed over said predetermined fuel cut speed, said fuel cut cycle including a fuel cut-off period and fuel resuming period, and said controller repeats fuel cut cycles until engine speed is decelerated below a predetermined fuel resuming speed.

Claim 5

A fuel injection control system as set forth in claim 3, wherein said controller orders fuel cut-off for said fuel cut-off period and subsequently orders fuel resumption for said fuel resuming period after said fuel cut period expires.

Claim 6

A fuel injection control system as set forth in claim 4. wherein said controller orders fuel cut-off at a timing corresponding to at the end of an intake valve open period after fuel cut-off condition is satisfied and orders fuel resumption at a timing corresponding to at the end of an intake valve open period after fuel resume condition is satisfied.

Claim 7

A fuel injection control system as set forth in claim 2, wherein said controller derives number of engine cylinders to block fuel delivery based on the excess magnitude of engine speed over said predetermined fuel cut speed for performing fuel cut-off operation for the determined number of engine cylinders and for maintaining fuel injection for remaining cylinders.

Claim 8

A fuel injection control system as set forth in claim 6, wherein said controller identifies engine cylinders to perform fuel cut-off based on the number of engine cylinders to perform fuel cut-off.

Claim 9

A fuel injection control system for an internal combustion engine, for performing fuel cut-off operation for blocking fuel delivery in response to an excessively high engine speed over a predetermined high engine speed criterion for protecting the engine, comprising: a fuel injection system including a fuel injection valve for delivering a controlled amount of fuel at a controlled timing; a sensor means for monitoring engine driving condition parameters including an engine revolution speed; and a controller, associated with said fuel injection system for controlling fuel delivery amount and fuel injection timing based on the engine driving parameters monitored by said sensor means, said controller being responsive to the engine revolution speed higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined high engine speed criterion, to initiate fuel cut-off operation, said controller driving a period of a fuel cut cycle, which fuel cut cycle period being variable depending upon magnitude of the engine speed over said predetermined fuel cut speed, said fuel cut cycle including a fuel cut-off period and fuel resuming period, and said controller repeats fuel cut cycle until engine is decelerated below a predetermined fuel resuming speed which is set in the vicinity of said predetermined high engine speed criterion and at a speed lower than said fuel cut-off speed.

Claim 10

A fuel injection control system for an internal combustion engine, for performing fuel cut-off operation for blocking fuel delivery in response to an excessively high engine speed over a predetermined high engine speed criterion for protecting the engine, comprising: a fuel injection system including a fuel injection valve for delivering a controlled amount of fuel at a controlled timing; a sensor means for monitoring engine driving condition parameters including an engine revolution speed; and a controller, associated with said fuel injection system for controlling fuel delivery amount and fuel injection timing based on the engine driving parameters monitored by said sensor means, said controller being responsive to the engine revolution speed higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined high engine speed criterion, to initiate fuel cut-off operation, said controller driving a period of a fuel cut cycle, which fuel cut cycle period being variable depending upon magnitude of the engine speed over said predetermined fuel cut speed, said fuel cut cycle including a fuel cut-off period and fuel resuming period, and said controller repeats fuel cut cycle until engine is decelerated below a predetermined fuel resuming speed which is set in the vicinity of said predetermined high engine speed criterion and at a speed lower than said fuel cut-off speed.

Claim 11

A fuel injection control system as set forth in claim 8, wherein said controller orders fuel cut-off for said fuel cut-off period and subsequently orders fuel resumption for said fuel resuming period after said fuel cut period expires.

Claim 12

A fuel injection control system as set forth in claim 9, wherein said controller orders fuel cut-off at a timing corresponding to at the end of an intake valve open period after fuel cut-off condition is satisfied and orders fuel resumption at a timing corresponding to at the end of an intake valve open period after fuel resume condition is satisfied.

Claim 13

A fuel injection control system for an internal combustion engine, for performing fuel cut-off operation for blocking fuel delivery in response to an excessively high engine speed over a predetermined high engine speed criterion for protecting the engine, comprising: a fuel injection system including a fuel injection valve for delivering a controlled amount of fuel at a controlled timing; a sensor means for monitoring engine driving condition parameters including an engine revolution speed; and a controller, associated with said fuel injection system for controlling fuel delivery amount and fuel injection timing based on the engine driving parameters monitored by said sensor means, said controller being responsive to the engine revolution speed higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined high engine speed criterion, to initiate fuel cut-off operation, said controller deriving number of engine cylinders to block fuel delivery based on the excess magnitude of engine speed over said predetermined fuel cut speed for performing fuel cut-off operation for the determined number of engine cylinders and for maintaining fuel injection for remaining cylinders.

Claim 14

A fuel injection control system for an internal combustion engine, for performing fuel cut-off operation for blocking fuel delivery in response to an excessively high engine speed over a predetermined high engine speed criterion for protecting the engine, comprising: a fuel injection system including a fuel injection valve for delivering a controlled amount of fuel at a controlled timing; a sensor means for monitoring engine driving condition parameters including an engine revolution speed; and a controller, associated with said fuel injection system for controlling fuel delivery amount and fuel injection timing based on the engine driving parameters monitored by said sensor means, said controller being responsive to the engine revolution speed higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined high engine speed criterion, to initiate fuel cut-off operation, said controller deriving number of engine cylinders to block fuel delivery based on the excess magnitude of engine speed over said predetermined fuel cut speed for performing fuel cut-off operation for the determined number of engine cylinders and for maintaining fuel injection for remaining cylinders.

Claim 15

A fuel injection control system as set forth in claim 11, wherein said controller orders fuel cut-off at a timing corresponding to at the end of an intake valve open period after fuel cut-off condition is satisfied and orders fuel resumption at a timing corresponding to at the end of an intake valve open period after fuel resume condition is satisfied.

Claim 16

A fuel injection control system as set forth in claim 11, wherein said controller identifies engine cylinders to perform fuel cut-off based on the number of engine cylinders to perform fuel cut-off.

Claim 17

A fuel delivery control system for an internal combustion engine, for performing fuel cut-off operation for blocking fuel delivery in response to an excessively high engine speed over a predetermined high engine speed criterion for protecting the engine, comprising: a fuel delivery system including a fuel delivery means for delivering a controlled amount of fuel at a controlled timing; a sensor means for monitoring engine driving condition parameters including an engine revolution speed; and a controller, associated with said fuel delivery system for controlling fuel delivery amount and fuel delivery timing based on the engine driving parameters monitored by said sensor means, said controller being responsive to the engine revolution speed higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined high engine speed criterion, to initiate fuel cut-off operation to intermittently block fuel delivery through said fuel delivery means.

Claim 18

A fuel delivery control system for an internal combustion engine, for performing fuel cut-off operation for blocking fuel delivery in response to an excessively high engine speed over a predetermined high engine speed criterion for protecting the engine, comprising: a fuel delivery system including a fuel delivery means for delivering a controlled amount of fuel at a controlled timing; a sensor means for monitoring engine driving condition parameters including an engine revolution speed; and a controller, associated with said fuel delivery system for controlling fuel delivery amount and fuel delivery timing based on the engine driving parameters monitored by said sensor means, said controller being responsive to the engine revolution speed higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined high engine speed criterion, to initiate fuel cut-off operation to intermittently block fuel delivery through said fuel delivery means.

Claim 19

A fuel delivery control system for an internal combustion engine, for performing fuel cut-off operation for blocking fuel delivery in response to an excessively high engine speed over a predetermined high engine speed criterion for protecting the engine, comprising: a fuel delivery system including a fuel delivery means for delivering a controlled amount of fuel at a controlled timing; a sensor means for monitoring engine driving condition parameters including an engine revolution speed; and a controller, associated with said fuel delivery system for controlling fuel delivery amount and fuel delivery timing based on the engine driving parameters monitored by said sensor means, said controller being responsive to the engine revolution speed higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined high engine speed criterion, to initiate fuel cut-off operation, said controller driving a period of a fuel cut cycle, which fuel cut cycle period being variable depending upon magnitude of the engine speed over said predetermined fuel cut speed, said fuel cut cycle including a fuel cut-off period and fuel resuming period, and said controller repeats fuel cut cycle until engine is decelerated below a predetermined fuel resuming sped which is set in the vicinity of said predetermined high engine speed criterion and at a speed lower than said fuel cut-off speed.

Claim 20

A fuel delivery control system for an internal combustion engine, for performing fuel cut-off operation for blocking fuel delivery in response to an excessively high engine speed over a predetermined high engine speed criterion for protecting the engine, comprising: a fuel delivery system including a fuel delivery means for delivering a controlled amount of fuel at a controlled timing; a sensor means for monitoring engine driving condition parameters including an engine revolution speed; and a controller, associated with said fuel delivery system for controlling fuel delivery amount and fuel delivery timing based on the engine driving parameters monitored by said sensor means, said controller being responsive to the engine revolution speed higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined high engine speed criterion, to initiate fuel cut-off operation, said controller driving a period of a fuel cut cycle, which fuel cut cycle period being variable depending upon magnitude of the engine speed over said predetermined fuel cut speed, said fuel cut cycle including a fuel cut-off period and fuel resuming period, and said controller repeats fuel cut cycle until engine is decelerated below a predetermined fuel resuming sped which is set in the vicinity of said predetermined high engine speed criterion and at a speed lower than said fuel cut-off speed.

Claim 21

A fuel delivery control system for an internal combustion engine, for performing fuel cut-off operation for blocking fuel delivery in response to an excessively high engine speed over a predetermined high engine speed criterion for protecting the engine, comprising: a fuel delivery system including a fuel delivery means for delivering a controlled amount of fuel at a controlled timing: a sensor means for monitoring engine driving condition parameters including an engine revolution speed; and a controller, associated with said fuel delivery system for controlling fuel delivery amount and fuel delivery timing based on the engine driving parameters monitored by said sensor means, said controller being responsive to the engine revolution speed higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined high engine speed criterion, to initiate fuel cut-off operation, said controller driving number of engine cylinders to block fuel delivery based on the excess magnitude of engine speed over said predetermined fuel cut speed for performing fuel cut-off operation for the determined number of engine cylinders and for maintaining fuel delivery for remaining cylinders.

Claim 22

A fuel delivery control system for an internal combustion engine, for performing fuel cut-off operation for blocking fuel delivery in response to an excessively high engine speed over a predetermined high engine speed criterion for protecting the engine, comprising: a fuel delivery system including a fuel delivery means for delivering a controlled amount of fuel at a controlled timing: a sensor means for monitoring engine driving condition parameters including an engine revolution speed; and a controller, associated with said fuel delivery system for controlling fuel delivery amount and fuel delivery timing based on the engine driving parameters monitored by said sensor means, said controller being responsive to the engine revolution speed higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined high engine speed criterion, to initiate fuel cut-off operation, said controller driving number of engine cylinders to block fuel delivery based on the excess magnitude of engine speed over said predetermined fuel cut speed for performing fuel cut-off operation for the determined number of engine cylinders and for maintaining fuel delivery for remaining cylinders.

Claim 23

A fuel injection control system for an internal combustion engine, for performing fuel cut-off operation for blocking fuel delivery in response to an excessively high engine speed over a predetermined high engine speed criterion for protecting the engine, comprising: a fuel injection system including a fuel injection valve for delivering a controlled amount of fuel at a controlled timing; a sensor means for monitoring engine driving condition parameters including an engine revolution speed and a crankshaft angular position; and a controller, associated with said fuel injection system for controlling fuel delivery amount and fuel injection timing based on the engine driving parameters monitored by said sensor means, said controller being responsive to the engine revolution speed higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined high engine speed criterion, to initiate fuel cut-off operation to intermittently block fuel delivery through said fuel injection valve, said controller deriving initiation timing on the basis of said crankshaft angular position and known valve timing of an intake valve for performing said fuel cut-off operation so that fuel cut-off is initiated at a close timing of an intake valve.

Claim 24

A fuel injection control system for an internal combustion engine, for performing fuel cut-off operation for blocking fuel delivery in response to an excessively high engine speed over a predetermined high engine speed criterion for protecting the engine, comprising: a fuel injection system including a fuel injection valve for delivering a controlled amount of fuel at a controlled timing; a sensor means for monitoring engine driving condition parameters including an engine revolution speed and a crankshaft angular position; and a controller, associated with said fuel injection system for controlling fuel delivery amount and fuel injection timing based on the engine driving parameters monitored by said sensor means, said controller being responsive to the engine revolution speed higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined high engine speed criterion, to initiate fuel cut-off operation to intermittently block fuel delivery through said fuel injection valve, said controller deriving initiation timing on the basis of said crankshaft angular position and known valve timing of an intake valve for performing said fuel cut-off operation so that fuel cut-off is initiated at a close timing of an intake valve.

Claim 25

A fuel injection control system for an internal combustion engine, for performing fuel cut-off operation for blocking fuel delivery in response to an excessively high engine speed over a predetermined high engine speed criterion for protecting the engine, comprising: a fuel injection system including a fuel injection valve for delivering a controlled amount of fuel at a controlled timing; a sensor means for monitoring engine driving condition parameters including an engine revolution speed and a crankshaft angular position; and a controller, associated with said fuel injection system for controlling fuel delivery amount and fuel injection timing based on the engine driving parameters monitored by said sensor means, said controller being responsive to the engine revolution speed higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined high engine speed criterion, to initiate fuel cut-off operation, said controller deriving a period of a fuel cut cycle, which fuel cut cycle period being variable depending upon magnitude of the engine speed over said predetermined fuel cut speed, said fuel cut cycle including a fuel cut-off period and fuel resuming period, and said controller repeats fuel cut cycle until engine is decelerated below a predetermined fuel resuming speed which is set in the vicinity of said predetermined high engine speed criterion and at a speed lower than said fuel cut-off speed, said controller driving initiation timing on the basis of said crankshaft angular position and known valve timing of an intake valve for performing said fuel cut-off and fuel resuming operation so that fuel cut-off and fuel resumption is initiated at a close timing of said intake valve.

Claim 26

A fuel injection control system for an internal combustion engine, for performing fuel cut-off operation for blocking fuel delivery in response to an excessively high engine speed over a predetermined high engine speed criterion for protecting the engine, comprising: a fuel injection system including a fuel injection valve for delivering a controlled amount of fuel at a controlled timing; a sensor means for monitoring engine driving condition parameters including an engine revolution speed and a crankshaft angular position; and a controller, associated with said fuel injection system for controlling fuel delivery amount and fuel injection timing based on the engine driving parameters monitored by said sensor means, said controller being responsive to the engine revolution speed higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined high engine speed criterion, to initiate fuel cut-off operation, said controller deriving a period of a fuel cut cycle, which fuel cut cycle period being variable depending upon magnitude of the engine speed over said predetermined fuel cut speed, said fuel cut cycle including a fuel cut-off period and fuel resuming period, and said controller repeats fuel cut cycle until engine is decelerated below a predetermined fuel resuming speed which is set in the vicinity of said predetermined high engine speed criterion and at a speed lower than said fuel cut-off speed, said controller driving initiation timing on the basis of said crankshaft angular position and known valve timing of an intake valve for performing said fuel cut-off and fuel resuming operation so that fuel cut-off and fuel resumption is initiated at a close timing of said intake valve.

Claim 27

A fuel injection control system for an internal combustion engine, for performing fuel cut-off operation for blocking fuel delivery in response to an excessively high engine speed over a predetermined high engine speed criterion for protecting the engine, comprising: a fuel injection system including a fuel injection valve for delivering a controlled amount of fuel at a controlled timing; a sensor means for monitoring engine driving condition parameters including an engine revolution speed and a crankshaft angular position; and a controller, associated with said fuel injection system for controlling fuel delivery amount and fuel injection timing based on the engine driving parameters monitored by said sensor means, said controller being responsive to the engine revolution speed higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined high engine speed criterion, to initiate fuel cut-off operation, said controller driving number of engine cylinders to block fuel delivery based on the excess magnitude of engine speed over said predetermined fuel cut speed for performing fuel cut-off operation for the determined number of engine cylinders and for maintaining fuel injection for remaining cylinders, said controller driving fuel cut-off initiation timing for each of engine cylinders on the basis of said crankshaft angular position and known valve timing of an intake valve for performing said fuel cut-off operation so that fuel cut-off is initiated at a close timing of said intake valve.

Claim 28

A fuel injection control system for an internal combustion engine, for performing fuel cut-off operation for blocking fuel delivery in response to an excessively high engine speed over a predetermined high engine speed criterion for protecting the engine, comprising: a fuel injection system including a fuel injection valve for delivering a controlled amount of fuel at a controlled timing; a sensor means for monitoring engine driving condition parameters including an engine revolution speed and a crankshaft angular position; and a controller, associated with said fuel injection system for controlling fuel delivery amount and fuel injection timing based on the engine driving parameters monitored by said sensor means, said controller being responsive to the engine revolution speed higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined high engine speed criterion, to initiate fuel cut-off operation, said controller driving number of engine cylinders to block fuel delivery based on the excess magnitude of engine speed over said predetermined fuel cut speed for performing fuel cut-off operation for the determined number of engine cylinders and for maintaining fuel injection for remaining cylinders, said controller driving fuel cut-off initiation timing for each of engine cylinders on the basis of said crankshaft angular position and known valve timing of an intake valve for performing said fuel cut-off operation so that fuel cut-off is initiated at a close timing of said intake valve.

Claim 29

In a fuel injection system for an internal combustion engine, means for performing a progressive fuel cut-off operation for restricting fuel delivery in response to the engine speed exceeding a predetermined upper value, to prevent the engine from attaining excessively high rotational speed without causing an abrupt change in an output torque of said engine, comprising: a sensor means for monitoring engine driving condition parameters including a revolution speed of said engine; a fuel injection system including a controlling means and a fuel injection valve, for delivering a controlled amount of fuel at a controlled timing, said amount and timing being in response to outputs from said sensing: means, said controller responding to the engine evaluation speed being higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined upper value, by causing a progressive fuel cut-off operation to block fuel delivery through said fuel injection valve by an amount corresponding to the magnitude by which said engine rotational speed exceeds said predetermined fuel cut speed, so as to prevent said engine from substantially exceeding said predetermined fuel cut speed without causing an abrupt change in an output torque of said engine.

Claim 30

In a fuel injection system for an internal combustion engine, means for performing a progressive fuel cut-off operation for restricting fuel delivery in response to the engine speed exceeding a predetermined upper value, to prevent the engine from attaining excessively high rotational speed without causing an abrupt change in an output torque of said engine, comprising: a sensor means for monitoring engine driving condition parameters including a revolution speed of said engine; a fuel injection system including a controlling means and a fuel injection valve, for delivering a controlled amount of fuel at a controlled timing, said amount and timing being in response to outputs from said sensing: means, said controller responding to the engine evaluation speed being higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined upper value, by causing a progressive fuel cut-off operation to block fuel delivery through said fuel injection valve by an amount corresponding to the magnitude by which said engine rotational speed exceeds said predetermined fuel cut speed, so as to prevent said engine from substantially exceeding said predetermined fuel cut speed without causing an abrupt change in an output torque of said engine.

Claim 31

In a fuel injection system for an internal combustion engine, a means for performing a progressive fuel cut-off operation for blocking fuel delivery to a number of cylinders of said engine in response to the engine speed exceeding a predetermined upper value, to prevent the engine from attaining excessively high rotational speed without causing an abrupt change in an output torque of said engine, comprising: a sensor means for monitoring engine driving condition parameters including a revolution speed of said engine; said fuel injection system including a controlling means and a plurality of fuel injection valves, said controller responding to the engine revolution speed being higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined upper value by determining which among said plurality of engine cylinders to which fuel delivery is to be blocked, said determined cylinders being progressively larger in number dependent on the excess magnitude of engine speed over said predetermined fuel cut speed, and causing a fuel cut-off operation to block fuel flow to said determined engine cylinders and maintaining fuel injection for remaining cylinders, by controlling fuel flow through a respective number of said fuel injection valves, so as to prevent said engine from substantially exceeding said predetermined fuel cut speed without causing an abrupt change in an output torque of said engine.

Claim 32

In a fuel injection system for an internal combustion engine, a means for performing a progressive fuel cut-off operation for blocking fuel delivery to a number of cylinders of said engine in response to the engine speed exceeding a predetermined upper value, to prevent the engine from attaining excessively high rotational speed without causing an abrupt change in an output torque of said engine, comprising: a sensor means for monitoring engine driving condition parameters including a revolution speed of said engine; said fuel injection system including a controlling means and a plurality of fuel injection valves, said controller responding to the engine revolution speed being higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined upper value by determining which among said plurality of engine cylinders to which fuel delivery is to be blocked, said determined cylinders being progressively larger in number dependent on the excess magnitude of engine speed over said predetermined fuel cut speed, and causing a fuel cut-off operation to block fuel flow to said determined engine cylinders and maintaining fuel injection for remaining cylinders, by controlling fuel flow through a respective number of said fuel injection valves, so as to prevent said engine from substantially exceeding said predetermined fuel cut speed without causing an abrupt change in an output torque of said engine.

Claim 33

In a fuel injection system for an internal combustion engine, a method for preventing the engine from attaining excessively high rotational speed without causing an abrupt change in an output torque of said engine, comprising the steps of: monitoring engine driving condition parameters including a revolution speed of said engine; delivering a controlled amount of fuel at a controlled timing in response to said monitored condition parameters; responding to the engine revolution speed being higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined upper value by causing a progressive fuel cut-off operation to block fuel delivery through said fuel injection valve by an amount corresponding to the magnitude by which said engine rotational speed exceeds said predetermined fuel cut speed, so as to prevent said engine from substantially exceeding said predetermined fuel cut speed without causing an abrupt change in an output torque of said engine.

Claim 34

In a fuel injection system for an internal combustion engine, a method for preventing the engine from attaining excessively high rotational speed without causing an abrupt change in an output torque of said engine, comprising the steps of: monitoring engine driving condition parameters including a revolution speed of said engine; delivering a controlled amount of fuel at a controlled timing in response to said monitored condition parameters; responding to the engine revolution speed being higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined upper value by causing a progressive fuel cut-off operation to block fuel delivery through said fuel injection valve by an amount corresponding to the magnitude by which said engine rotational speed exceeds said predetermined fuel cut speed, so as to prevent said engine from substantially exceeding said predetermined fuel cut speed without causing an abrupt change in an output torque of said engine.

Claim 35

In a fuel injection system for an internal combustion engine, a method for preventing the engine from attaining excessively high rotational speed without causing an abrupt change in an output torque of said engine, comprising the steps of: monitoring engine driving condition parameters including a revolution speed of said engine; delivering a controlled amount of fuel at a controlled timing in response to said monitored condition parameters; responding to the engine revolution speed being higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined upper value by determining which among said plurality of engine cylinders to which fuel delivery is to be blocked, said determined cylinders being progressively larger in number dependant on the excess magnitude of engine speed over said predetermined fuel cut speed; and blocking fuel flow to said determined engine cylinders and maintaining fuel injection for remaining cylinders, so as to prevent said engine from substantially exceeding said predetermined fuel cut speed without causing an abrupt change in an output torque of said engine.

Claim 36

In a fuel injection system for an internal combustion engine, a method for preventing the engine from attaining excessively high rotational speed without causing an abrupt change in an output torque of said engine, comprising the steps of: monitoring engine driving condition parameters including a revolution speed of said engine; delivering a controlled amount of fuel at a controlled timing in response to said monitored condition parameters; responding to the engine revolution speed being higher than a predetermined fuel cut speed which is set in the vicinity of said predetermined upper value by determining which among said plurality of engine cylinders to which fuel delivery is to be blocked, said determined cylinders being progressively larger in number dependant on the excess magnitude of engine speed over said predetermined fuel cut speed; and blocking fuel flow to said determined engine cylinders and maintaining fuel injection for remaining cylinders, so as to prevent said engine from substantially exceeding said predetermined fuel cut speed without causing an abrupt change in an output torque of said engine.