Vehicle starter and electrical system protection

Abstract

A protective control box is disclosure for providing protection for a starter system and other components of equipment, such as vehicles, incorporating internal combustion engines. Improved starter protection apparatus and circuitry using frequency to voltage conversion disables a starter motor from starting the internal combustion engine when engine speed exceeds a pre-determined level. The starter cannot be re-actuated until and unless engine speed has fallen below a second lower pre-determined speed level. The protection box includes a lockout solenoid which in turn selectively locks out the main starter solenoid in accordance with the foregoing conditions. A wait-to-start lamp and associated comparator and latching circuitry is provided for actuating the wait lamp in response to initiation of glow plug controller pre-glow operation, and for subsequently extinguishing the lamp. Once extinguished, the lamp cannot be re-actuated until and unless the ignition has been toggled. Circuitry including a field effect transistor is provided for controlling glow plug controller operation by means of an auxiliary solenoid. Load dump control circuitry responsive to frequency to voltage conversion inhibits disconnection of electrical loads from a motor-driven alternator even when the ignition is turned off, until engine speed has dropped to a safe level. This prevents voltage spikes which would otherwise result from the sudden unloading of the alternator, a phenomenon which could damage a voltage regulator or other electrical circuitry. After-glow control maintains glow plug controller operation until ambient engine temperature has reached a pre-determined level.