The goal was to design a basic logic circuit with a timer that energizes the ignition coils 1s after the oil pressure switch opens. The coils will be DE-ENERGIZED under the following conditions:
1. If the oil pressure switch closes due to loss of oil pressure (the engine isn't running OR the engine isn't cranking fast enough to produce sufficient oil pressure to open the oil pressure switch).
2. If the deadman switch is opened
3. If the keyswitch is turned off
If someone attempts to start the bike yet releases the starter button midway, the oil pressure in the engine will drop, close the oil pressure switch, deactivate the timer, the coils will de-energize, and the delay sequence will be restarted when the bike is cranked again.
Detailed Sequence:
1. When the keyswitch is turned ON, power flows to terminal 30 on relay K1. Terminal 86 on K1 is permanently grounded.
2. When the deadman switch is closed, power flows to coil terminal 85 on relay K1 and K2 - at this point K1 will close and allow power to flow to terminal 30 on K2. Closing the deadman also allows power to flow to input terminal 87a on the timer.
3. If the engine is not running, the will be no oil pressure, and the oil pressure switch will be closed, causing coil terminal 86 or relay K2 to be grounded, causing K2 to open, preventing power from flowing to terminal 86 on the timer (this DEACTIVATES THE TIMER). Terminal 87 on the timer will also be grounded.
4. When the bike cranks, oil pressure opens the oil pressure switch causing relay K2 to revert to the NC state, allowing power to flow to terminal 86 on the timer. The open oil pressure switch also removed the ground path from terminal 87 on the timer, and thus, the only active input on the timer is the +12V on terminal 87A. Because the timer has power on terminal 86 and and 87a, it will activate and close in 1s, thus connecting terminal 86 to terminal 30 and allow power to flow to the ignition coil. At this point, the engine has been spinning for however long it takes to create oil pressure + 1s, which should be long enough to prevent kickback once the coils are energized.
The ground from the closed oil pressure switch to terminal 87 on the timer is a "safety" of sorts - if for some reason relay K2 malfunctions and allows power to flow to terminal 86 on the timer in all states, the timer will not activate until the oil pressure switch opens and the ground is removed from terminal 87. Thus, the only active input to the timer is +12V on terminal 87A.
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