Electronically controlled fuel injection method and apparatus

Claim 3

Apparatus for electronically controlling the rate of fuel being injected at low engine temperatures into an engine having a combustion chamber and a crank-shaft comprising: means for monitoring a pressure P in said combustion chamber; microcomputer processing means for (1) determining said P at a plurality of predetermined intervals during compression and explosion strokes from 180° before top dead center to 180° after top dead center and during each intake stroke and exhaust stroke, (2) generating, in response to said determining step, an integrated pressure value Pi related to the integral of the product of P and the incremental change in combustion chamber volume per incremental change in crank-shaft angle over the range of crank-shaft angles from 180° before top dead center to 180° after top dead center during the compression and explosion strokes, (3) generating a pumping means effective pressure value P p related to the difference between combustion chamber pressures during an intake stroke and an exhaust stroke of said engine, (4) generating a torque value T related to said Pi less Pf and said P p where Pf is related to a frictional average effective pressure, and (5) determining the amount by which said fuel injection rate should be adjusted so that T approaches a predetermined optimum torque, said microcomputer processing means functions (3), (4) and (5) occurring during one of an exhaust stroke and an intake stroke of said engine; and means, responsive to said microcomputer processing means for adjusting said fuel injection rate.

Claim 4

Apparatus for electronically controlling the rate of fuel being injected at low engine temperatures into an engine having a combustion chamber and a crank-shaft comprising: means for monitoring a pressure P in said combustion chamber; microcomputer processing means for (1) determining said P at a plurality of predetermined intervals during compression and explosion strokes from 180° before top dead center to 180° after top dead center and during each intake stroke and exhaust stroke, (2) generating, in response to said determining step, an integrated pressure value Pi related to the integral of the product of P and the incremental change in combustion chamber volume per incremental change in crank-shaft angle over the range of crank-shaft angles from 180° before top dead center to 180° after top dead center during the compression and explosion strokes, (3) generating a pumping means effective pressure value P p related to the difference between combustion chamber pressures during an intake stroke and an exhaust stroke of said engine, (4) generating a torque value T related to said Pi less Pf and said P p where Pf is related to a frictional average effective pressure, and (5) determining the amount by which said fuel injection rate should be adjusted so that T approaches a predetermined optimum torque, said microcomputer processing means functions (3), (4) and (5) occurring during one of an exhaust stroke and an intake stroke of said engine; and means, responsive to said microcomputer processing means for adjusting said fuel injection rate.

Claim 5

A method as defined in claim 1, wherein said step (b) includes the step of determining P during a compression stroke and an explosion stroke at every change through a predetermined angle of the crank-shaft.

Claim 6

A method as defined in claim 3, wherein said step (a) includes the step of determining P only a single point respectively during an intake stroke and an exhaust stroke of said engine.

Claim 7

A method as defined in claim 1, wherein said step (f) includes the step of adjusting said fuel injection rate so that a mean torque of said T averaged over 5 cycles approaches said optimum torque.

Claim 8

A method as defined in claim 3, wherein said predetermined angle is 3°.

Claim 9

Apparatus as in claim 2 wherein said microcomputer processing means determines said P during said compression and explosion strokes each time said crank-shaft rotates a predetermined angle.

Claim 10

Apparatus as in claim 7 wherein said predetermined angle is 3°.

Claim 11

Apparatus as in claim 2 wherein said microcomputer processing means determines said P only once during each intake stroke and each exhaust stroke.

Claim 12

Apparatus as in claim 2 wherein said microcomputer processing means averages said T over five cycles and determines the amount by which said fuel injection rate should be adjusted so that said averages approaches said optimum value.