Device for limiting the speed of internal-combustion engine

Claim 1

A device for limiting the speed of an internal combustion engine having a shaft, an ignition coil including a primary winding (11, 31) and a secondary winding (12, 32), an engine spark plug (17, 37) connected with the secondary winding, and a charging capacitor (10, 30) connected in circuit with the primary winding for controlling the discharge of the capacitor to produce a controlled discharge voltage therefrom to controllably activate the spark plug, comprising: a rotatable member (5, 25) connected with said shaft; a single rotatable magnet system (4, 24) carried by said rotatable member for rotation therewith; a stationary first core (2, 22) including a front face disposed adjacent to and in close proximity to the outer periphery of said rotatable member, a charging coil (1, 21) mounted about said core for producing an electric pulse for each rotation of said rotatable member; a stationary second core (8, 28) mounted in close proximity to said rotatable member and displaced in phase from said stationary first core by an adjustable angular position relative to said charging coil, a single stationary triggering coil (7, 27) mounted about said second core, the position of said second core being present with respect to said first core to satisfy a predetermined maximum speed value of said engine; rectifier means (9, 29a) coupled to said charging coil responsive to the electric pulse output therefrom for rectifying the pulse output, said capacitor having an input coupled to the output of said rectifying means; a semi-conductor switch (13, 33) connected between said rectifier means output and said input of said capacitor, the input gate of said switch being coupled to said triggering coil and responsive to a pulse therefrom to inhibit said capacitor from being fully charged from a rectifier means and thereby limiting the discharge voltage from said capacitor to said primary winding, thereby limiting the engine to a maximum speed value; a resistor (15, 35) connected in parallel with said triggering coil, said resistor having a value correlated to the maximum speed value and the characteristics of said magnet system; and means adjusting the angular position of said triggering coil with respect to said charging coil to activate the spark plug when engine rotation is below said maximum speed value, said switch being responsive to said triggering coil to prevent full build up of charge on said capacitor in response to engine rotation at said maximum speed value thereby applying said pulse from said triggering coil to said switch while the output from said rectifier means is applied to said capacitor, said spark plug being prevented from being activated in response to less than full build up of charge on said capacitor when said maximum speed value is attained.

Claim 2

A device for limiting the speed of an internal combustion engine having a shaft, an ignition coil including a primary winding (11, 31) and a secondary winding (12, 32), an engine spark plug (17, 37) connected with the secondary winding, and a charging capacitor (10, 30) connected in circuit with the primary winding for controlling the discharge of the capacitor to produce a controlled discharge voltage therefrom to controllably activate the spark plug, comprising: a rotatable member (5, 25) connected with said shaft; a single rotatable magnet system (4, 24) carried by said rotatable member for rotation therewith; a stationary first core (2, 22) including a front face disposed adjacent to and in close proximity to the outer periphery of said rotatable member, a charging coil (1, 21) mounted about said core for producing an electric pulse for each rotation of said rotatable member; a stationary second core (8, 28) mounted in close proximity to said rotatable member and displaced in phase from said stationary first core by an adjustable angular position relative to said charging coil, a single stationary triggering coil (7, 27) mounted about said second core, the position of said second core being present with respect to said first core to satisfy a predetermined maximum speed value of said engine; rectifier means (9, 29a) coupled to said charging coil responsive to the electric pulse output therefrom for rectifying the pulse output, said capacitor having an input coupled to the output of said rectifying means; a semi-conductor switch (13, 33) connected between said rectifier means output and said input of said capacitor, the input gate of said switch being coupled to said triggering coil and responsive to a pulse therefrom to inhibit said capacitor from being fully charged from a rectifier means and thereby limiting the discharge voltage from said capacitor to said primary winding, thereby limiting the engine to a maximum speed value; a resistor (15, 35) connected in parallel with said triggering coil, said resistor having a value correlated to the maximum speed value and the characteristics of said magnet system; and means adjusting the angular position of said triggering coil with respect to said charging coil to activate the spark plug when engine rotation is below said maximum speed value, said switch being responsive to said triggering coil to prevent full build up of charge on said capacitor in response to engine rotation at said maximum speed value thereby applying said pulse from said triggering coil to said switch while the output from said rectifier means is applied to said capacitor, said spark plug being prevented from being activated in response to less than full build up of charge on said capacitor when said maximum speed value is attained.