Test device for automobile engine idle speed control circuit
First Claim
1. A test instrument for driving a two-coil stepper motor comprising a four-pole multi-position non-shorting mechanical rotary switch connected for switching polarities from a direct current source to both coils of said stepper motor with each step of said rotary switch from one said position to another thereby to turn said stepper motor in one step increments for each said step of said rotary switch in a direction dependent on the direction of movement of said rotary switch.
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Accused Products
Abstract
A portable self-contained instrument for testing the idle speed control system in an automotive engine includes LED indicators for displaying engine computer output pulses to the idle speed stepper motor, and a multi-pole rotary switch connected to an internal battery for deriving the voltages necessary for exercising the stepper motor. A mode switch allows normal engine operation while monitoring the computer output on the LEDs, or connects the rotary switch for controlling the stepper motor while disabling the computer.
21 Citations
18 Claims
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1. A test instrument for driving a two-coil stepper motor comprising a four-pole multi-position non-shorting mechanical rotary switch connected for switching polarities from a direct current source to both coils of said stepper motor with each step of said rotary switch from one said position to another thereby to turn said stepper motor in one step increments for each said step of said rotary switch in a direction dependent on the direction of movement of said rotary switch.
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2. A test instrument for testing the operation of the idle speed control system in an automotive engine where the idle speed is set by a two-coil stepper motor driven through a multi-conductor engine cable connected to the output of an engine control computer, comprising:
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indicator means for displaying output signals of said control computer on said engine cable; stepper drive means for driving said stepper motor; first connector means for connecting said indicator means to said engine cable; second connector means for connecting to the coils of said stepper motor; and first switch means for selectively connecting said second connector means either to said stepper drive means in a first mode of operation or to said first connector means in a second mode of operation of said test instrument. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10)
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11. A test instrument for testing the operation of the idle speed control system in an automotive engine where the idle speed is set by a two-coil stepper motor driven by an engine control computer through a four conductor engine cable, comprising:
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a common housing; visual indicator means mounted to said housing associated with each conductor of said engine cable for displaying computer output signals on said each conductor; first connector means for connecting said indicator means to said engine cable; second connector means for connecting to the coils of said stepper motor; a battery in said housing; first switch means mounted to said housing and connected to said battery for mechanically switching polarities at said second connector means to turn said stepper motor in one step increments in a selected direction; and second switch means mounted to said housing for selectively connecting said second connector means either to said first switch means in a first mode of operation or to said first connector means in a second mode of operation of said test instrument. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A test instrument for testing the operation of the idle speed control system in an automotive engine where the idle speed is set by a two-coil stepper motor driven by an engine control computer through a four conductor engine cable, comprising:
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visual indicator means associated with each conductor of said engine cable for displaying computer output signals on said each conductor; first connector means for connecting said indicator means to said engine cable; second connector means for connecting to the coils of said stepper motor; mode switch means for selectively connecting said second connector means either to said stepper drive means in a first mode of operation or to said first connector means in a second mode of operation of said test instrument; and a four-pole multi-position non-shorting mechanical rotary second switch connected to a direct current source for switching polarities at said second connector means with each step of said second switch from one said position to another in a sequence adapted to turn said stepper motor in one step increments in a direction dependent on the direction of movement of said second switch.
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Specification