Electronic engine r.p.m. limiting device

Claim 2

An electronic device for limiting the speed of an internal combustion engine having an ignition coil including a primary winding and a direct current source series connected to one side of said primary winding, said limiting device comprising: switching means connected in series with said series connected primary winding and direct current source and responsive to said engine speed for alternate actuation to allow current flow through said primary winding and deactuation to interrupt said current flow at an actuation frequency proportional to said engine speed; sensing means responsively coupled to said switching means for generating an output signal when said actuating frequency reaches a predetermined value; a silicon-controlled rectifier connected across said switching means and having a gate electrode, said output signal generated by said sensing means being coupled to said gate electrode, said silicon-controlled rectifier becoming conductive to allow continuous current flow through said primary winding when said output signal is generated by said sensing means.

Claim 3

The device as described in claim 1 wherein said sensing means includes (i) an RC charging network including a charging capacitor coupled to said direct current source, and (ii) discharge meanS responsively coupled to said switching means for discharging said each time said switching means interrupts said current flow through said primary winding, said direct current source charging said charging capacitor to a predetermined voltage potential by a charging current intermediate said discharges, the average value of said charging current being proportional to said engine speed.

Claim 4

The device as described in claim 2 wherein said sensing means further includes a detector means responsive to said charging current for generating said output signal to said gate electrode of said silicon-controlled rectifier when the average value of said charging current reaches a predetermined value.

Claim 5

The device as described in claim 3 wherein said switching means comprises mechanical breaker points and wherein said sensing means further includes a diode coupled in parallel with said mechanical breaker points.

Claim 6

The device as described in claim 3 wherein said switching means comprise a transistorized circuit including a switching transistor connected in series with said primary winding said switching transistor becoming alternately conductive and nonconductive at a frequency proportional to said engine speed.

Claim 7

The device as described in claim 5 wherein said switching means further includes a photoelectric timing means coupled to said engine for generating an output timing signal having a frequency proportional to said engine speed, said timing signal being coupled to the base electrode of said switching transistor.

Claim 8

The device as described in claim 1 wherein said silicon-controlled rectifier is series connected with a resistor, said series connected silicon-controlled rectifier and resistor being connected in parallel to said switching means, and wherein said sensing means is responsive to current flowing through said series connected silicon-controlled rectifier and resistor when said silicon-controlled rectifier is conductive.

Claim 9

A solid-state device for limiting the speed of an internal combustion engine having a direct current source connected to the primary winding of an ignition coil, said limiting device comprising: means driven by said engine for generating timing signals synchronized with the speed of said engine; pulse-shaping means responsive to said timing means for generating a square wave having a frequency determined by said timing signals; switching means in series with said primary winding and responsive to said pulse shaping means, said switching means allowing current flow through said primary winding when actuated and interrupting said current flow when deactuated, said ignition coil generating an ignition pulse when said current flow is interrupted; sensing means responsive to said engine speed for generating an output signal when said engine speed exceeds a predetermined value; and a silicon-controlled rectifier connected in parallel with said switching means and having a gate electrode coupled to said sensing means output signal, said silicon-controlled rectifier becoming conductive when said sensing means generates said output signal to allow continuous current flow through said primary winding.

Claim 10

A solid-state device for limiting the speed of an internal combustion engine having a direct current source connected to the primary winding of an ignition coil, said limiting device comprising: means driven by said engine for generating timing signals synchronized with the speed of said engine; pulse-shaping means responsive to said timing means for generating a square wave having a frequency determined by said timing signals; switching means in series with said primary winding and responsive to said pulse shaping means, said switching means allowing current flow through said primary winding when actuated and interrupting said current flow when deactuated, said ignition coil generating an ignition pulse when said current flow is interrupted; sensing means responsive to said engine speed for generating an output signal when said engine speed exceeds a predetermined value; and a silicon-controlled rectifier connected in parallel with said switching means and having a gate electrode coupled to said sensing means output signal, said silicon-controlled rectifier becoming conductive when said sensing means generates said output signal to allow continuous current flow through said primary winding.

Claim 11

The device as described in claim 8 wherein said sensing means includes (i) an RC charging network having a charging capacitor coupled to said direct current source and (ii) a discharge means coupled to said charging capacitor and responsive to said engine speed for discharging said charging capacitor at a rate proportional to said engine speed, said direct current source charging said charging capacitor by a charging current intermediate said discharges, the average value of said charging current being proportional to said engine speed.

Claim 12

The device as described in claim 9 wherein said sensing means further includes a detector means responsive to said charge current for generating said output signal when the average value of said charging current reaches a value corresponding to a predetermined engine speed.

Claim 13

In an internal combustion engine having an ignition system including an ignition coil having a primary and a secondary winding, and a direct current source coupled to one side of said primary winding an engine r.p.m. limiting device comprising: switching means having a first terminal connected to ground and a second terminal coupled to the other side of said primary winding and responsive to the speed of said engine for actuating to allow current flow from said direct current source through said primary winding and deactuating to interrupt said current flow at an actuation frequency proportional to said engine speed, said ignition coil generating an ignition pulse when said current flow is interrupted; a diode having an anode and a cathode connected to said first and second terminals respectively of said switching means; a silicon-controlled rectifier having (i) an anode electrode coupled to said second terminal of said switching means, (ii) a cathode electrode coupled to said first terminal of said switching means, and (iii) a gate electrode, said silicon-controlled rectifier becoming conductive to disable said ignition system when an appropriate signal is applied to said gate electrode; a resistor connected intermediate said cathode electrode of said silicon-controlled rectifier and said first terminal of said switching means, and a sensing means coupled to said second terminal of said switching means and responsive to said ignition pulses generated by said ignition coil for generating an output signal to said gate electrode of said silicon-controlled rectifier to disable said ignition system when said ignition pulses occur at a frequency corresponding to a predetermined engine speed, said control means being further responsive to current flow through said series connected silicon-controlled rectifier and resistor to maintain said output signal to said gate electrode when said ignition system is disabled until said engine speed slows to a value below said predetermined value.

Claim 14

In an internal combustion engine having an ignition system including an ignition coil having a primary and a secondary winding, and a direct current source coupled to one side of said primary winding an engine r.p.m. limiting device comprising: switching means having a first terminal connected to ground and a second terminal coupled to the other side of said primary winding and responsive to the speed of said engine for actuating to allow current flow from said direct current source through said primary winding and deactuating to interrupt said current flow at an actuation frequency proportional to said engine speed, said ignition coil generating an ignition pulse when said current flow is interrupted; a diode having an anode and a cathode connected to said first and second terminals respectively of said switching means; a silicon-controlled rectifier having (i) an anode electrode coupled to said second terminal of said switching means, (ii) a cathode electrode coupled to said first terminal of said switching means, and (iii) a gate electrode, said silicon-controlled rectifier becoming conductive to disable said ignition system when an appropriate signal is applied to said gate electrode; a resistor connected intermediate said cathode electrode of said silicon-controlled rectifier and said first terminal of said switching means, and a sensing means coupled to said second terminal of said switching means and responsive to said ignition pulses generated by said ignition coil for generating an output signal to said gate electrode of said silicon-controlled rectifier to disable said ignition system when said ignition pulses occur at a frequency corresponding to a predetermined engine speed, said control means being further responsive to current flow through said series connected silicon-controlled rectifier and resistor to maintain said output signal to said gate electrode when said ignition system is disabled until said engine speed slows to a value below said predetermined value.

Claim 15

The device as described in claim 11 wherein said sensing means includes an RC charging network including a charging capacitor coupled to said direct current source and discharge means responsive to said ignition pulses generated by said ignition coil and coupled to said charging capacitor for discharging said charging capacitor at a frequency determined by the frequency of said ignition pulses, said direct current source charging said charging capacitor with a changing current intermediate said discharges, the average value of said charge current being proportional to said engine speed.

Claim 16

The device as described in claim 12 wherein said sensing means further includes a detector means responsive to said charge current for generating said output signal when the average value of said charging current reaches a value corresponding to a predetermined engine speed.

Claim 17

The device as described in claim 13 wherein said switching means comprises mechanical breaker points.

Claim 18

The device as described in claim 13 wherein said switching means comprises a photoelectric timing means responsive to said engine speed for generating a timing signal proportional to said engine speed, and a switching transistor connected in series with said primary winding said switching transistor having a base electrode responsively coupled to said timing signal.

Claim 19

The device defined in claim 1 wherein said current flow through said silicon-controlled rectifier is limited when said silicon-controlled rectifier is conductive, to inhibit ignition pulses while allowing sufficient current changes in said primary circuit to allow actuation of said sensing means, thereby allowing operation of said device while the ignition system is disabled.

Claim 20

The device defined in claim 1 additionally comprising: a diode, parallel connected to said switching means, said diode eliminating spurious signals from said switching means and thereby allowing said sensing means to produce said output signal at a frequency no lower than said predetermined frequency.

Claim 21

A solid-state device for limiting the speed of an internal combustion engine having a direct current source connected to the primary winding of an ignition coil, said limiting device comprising: means driven by said engine for generating timing signals synchronized with the speed of said engine; pulse shaping means responsive to said timing means for generating a square wave having a frequency determined by said timing signals; switching means in series with said primary winding and responsive to said pulse shaping means, said switching means allowing current flow through said primary winding when actuated and interrupting said current flow when deactuated, said ignition coil generating an ignition pulse when said current flow is interrupted; a capacitor; means responsive to said engine speed for charging said capacitor; sensing means responsive to said capacitor charging means for generating an output signal when said engine speed exceeds a predetermined value; and a silicon-controlled rectifier connected in parallel with said switching means and having a gate electrode coupled to said sensing means output signal, said silicon-controlled rectifier becoming conductive when said sensing means generates said output signal to allow continuous current through said primary winding.

Claim 22

A solid-state device for limiting the speed of an internal combustion engine having a direct current source connected to the primary winding of an ignition coil, said limiting device comprising: means driven by said engine for generating timing signals synchronized with the speed of said engine; pulse shaping means responsive to said timing means for generating a square wave having a frequency determined by said timing signals; switching means in series with said primary winding and responsive to said pulse shaping means, said switching means allowing current flow through said primary winding when actuated and interrupting said current flow when deactuated, said ignition coil generating an ignition pulse when said current flow is interrupted; a capacitor; means responsive to said engine speed for charging said capacitor; sensing means responsive to said capacitor charging means for generating an output signal when said engine speed exceeds a predetermined value; and a silicon-controlled rectifier connected in parallel with said switching means and having a gate electrode coupled to said sensing means output signal, said silicon-controlled rectifier becoming conductive when said sensing means generates said output signal to allow continuous current through said primary winding.

Claim 23

The device as described in claim 18 wherein said capacitor charging means charges said capacitor with a charging current the average value of which is proportional to said engine speed.

Claim 24

An electronic device for limiting the speed of an internal combustion engine having an ignition coil including a primary winding and a direct current source series connected to one side of said primary winding, said limiting device comprising: switching means connected in series with said series connected primary winding and direct current source and responsive to said engine speed for alternately actuating to allow current flow to be said primary winding and deactuating to interrupt said current flow at an actuation frequency proportional to said engine speed; a diode parallel connected with said switching means, to control the waveform produced by said switching means; and control means responsive to said switching means for inhibiting the operation of said ignition coil when said actuation frequency reaches a predetermined level.

Claim 25

An electronic device for limiting the speed of an internal combustion engine having an ignition coil including a primary winding and a direct current source series connected to one side of said primary winding, said limiting device comprising: switching means connected in series with said series connected primary winding and direct current source and responsive to said engine speed for alternately actuating to allow current flow to be said primary winding and deactuating to interrupt said current flow at an actuation frequency proportional to said engine speed; a diode parallel connected with said switching means, to control the waveform produced by said switching means; and control means responsive to said switching means for inhibiting the operation of said ignition coil when said actuation frequency reaches a predetermined level.

Claim 26

An electronic device for limiting the speed of an internal combustion engine having an ignition coil including a primary winding and a direct current source series connected to one side of said primary winding, said limiting device comprising: switching means connected in series with said series connected primary winding and direct current source and responsive to said engine speed for alternate actuation to allow current flow through said primary winding and deactuation to interrupt said current flow at an actuation frequency proportional to said engine speed; sensing means responsively coupled to said switching means for generating an output signal determined by said actuation frequency; and a solid-state switch connected across said switching means and having a gate electrode, said output signal generated by said sensing means being coupled to said gate electrode, said solid-state switch becoming conductive to allow continuous current flow through said primary winding when said actuation frequency reaches a predetermined value.

Claim 27

An electronic device for limiting the speed of an internal combustion engine having an ignition coil including a primary winding and a direct current source series connected to one side of said primary winding, said limiting device comprising: switching means connected in series with said series connected primary winding and direct current source and responsive to said engine speed for alternate actuation to allow current flow through said primary winding and deactuation to interrupt said current flow at an actuation frequency proportional to said engine speed; sensing means responsively coupled to said switching means for generating an output signal determined by said actuation frequency; and a solid-state switch connected across said switching means and having a gate electrode, said output signal generated by said sensing means being coupled to said gate electrode, said solid-state switch becoming conductive to allow continuous current flow through said primary winding when said actuation frequency reaches a predetermined value.

Claim 28

An electronic device as defined in claim 21 additionally comprising: a resistor, series connected with said solid-state switch, said series resistor and solid-state switch being connected in parallel with said switching means, said solid-state switch, when conductive, allowing current flow through said coil primary and said resistor when said switching means is deactuated, said resistor having a value which is sufficiently low that changes in the current flow through saId primary winding caused by actuation and deactuation of said switching means when said solid-state switch is conductive will not produce ignition pulses; and sensing means is responsive to changes in the current flow in said primary winding caused by actuation and deactuation of said switching means regardless of actuation or deactuation of said solid-state switch.