Contactless ignition system for internal combustion engine

Claim 2

A contactless ignition system for an internal combustion engine, said ignition system comprising: a signal generator means for producing a signal voltage in synchronism with the rotation of the engine, the magnitude of said signal voltage increasing in accordance with increasing rotational speed of the engine, a saturation amplifier means with its input effectively connected to said signal generator means for producing an amplified output signal which becomes saturated when said signal voltage reaches a predetermined level, a level regulator means for controlling an input bias to said amplifier, an amplification regulator means for controlling the amplification factor of said saturation amplifier means thereby controlling the time period during which said output signal is saturated, and an AC coupling circuit for connecting the AC components of the amplified output signal of said saturation amplifier as an input AC signal to a succeeding circuit said succeeding circuit including a level detecting circuit for producing an ignition signal by detecting a predetermined level of said input AC signal applied to said succeeding circuit through said AC coupling circuit whereby the effective advance of said ignition signal is determined by the period during which said output signal from said saturation amplifier is saturated.

Claim 3

A contactless ignition system according to claim 1, further comprising means for supplying said amplification regulator means with said signal voltage from said signal generator means and for producing a control signal corresponding to a desired ignition advance angle with the amplification factor of said saturation amplifier means being controlled by said control signal produced by said amplification regulator means.

Claim 6

A system for automatically advancing an ignition angle as in claim 3, wherein: said saturation amplifier means has an amplification factor which is of a relatively high value when the engine rotation is lower than a predetermined value and which is then controllably decreased in accordance with increasing engine rotational speeds.

Claim 7

A system automatically advancing an ignition angle as in claim 3, wherein: said saturation amplifier means comprises: a first transistor having an emitter, collector and base an output resistance connected between the collector of said first transistor and a power terminal which is connectable to a power source, an emitter resistance connected between the emitter of said first transistor and a ground potential terminal, and a variable resistance connected between the base of said first transistor and said power terminal and wherein: said amplification regulator means comprises: a series electrical circuit of a second transistor having an emitter, collector and base, and a resistor connected in series with the emitter-collector of said second transistor, said series circuit being connected in parallel with said emitter resistance.

Claim 8

An improvement for an internal combustion engine automatic ignition advance system of the type that utilizes a level detector to determine ignition timing by detecting when an input AC signal in synchronism with engine rotation exceeds a preset trigger level where the input AC signal is normally taken directly or after linear amplification as a signal voltage from a signal generator operated in synchronism with the engine and producing higher signal voltages as the engine speed is increased, said improvement comprising: a saturation amplifier means with an input effectively electrically connected to an output of said signal generator for producing a saturated output signal which is saturated for at least part of each cycle of an AC signal output from said signal generator after the engine rotational speed exceeds a predetermined value and which becomes increasingly saturated as higher voltages are applied to its input in response to higher engine rotational speeds, an AC coupling means connected between an output of said saturation amplifier means and an input of said level detector for passing the AC component only of said saturated output signal to the level detector whereby the effective magnitude of ignition advance is determined by the degree of saturation of said saturation amplifier means, and means for controlling the degree of saturation of said saturation amplifier means.

Claim 9

An improvement for an internal combustion engine automatic ignition advance system of the type that utilizes a level detector to determine ignition timing by detecting when an input AC signal in synchronism with engine rotation exceeds a preset trigger level where the input AC signal is normally taken directly or after linear amplification as a signal voltage from a signal generator operated in synchronism with the engine and producing higher signal voltages as the engine speed is increased, said improvement comprising: a saturation amplifier means with an input effectively electrically connected to an output of said signal generator for producing a saturated output signal which is saturated for at least part of each cycle of an AC signal output from said signal generator after the engine rotational speed exceeds a predetermined value and which becomes increasingly saturated as higher voltages are applied to its input in response to higher engine rotational speeds, an AC coupling means connected between an output of said saturation amplifier means and an input of said level detector for passing the AC component only of said saturated output signal to the level detector whereby the effective magnitude of ignition advance is determined by the degree of saturation of said saturation amplifier means, and means for controlling the degree of saturation of said saturation amplifier means.

Claim 10

An improvement as in claim 6 wherein said means for controlling comprises: an amplification regulator means effectively connected to said signal generator and to said saturation amplifier means for controlling the amplification factor of said saturation amplifier means in accordance with the output from said signal generator to cause the amplification factor, and hence the degree of saturation, to decrease with increasing engine rotational speeds thereby resulting in lesser ignition advance angles at higher engine speeds.

Claim 11

An improvement as in claim 7 wherein said saturation amplifier means comprises a transistor amplifier including controlled bias means for determining the predetermined value of engine rotational speed beyond which the output of said transistor amplifier is saturated.