hello gents
im hoping some of you fine folks can steer me in the right direction here. i need to make a self adjusting temperature regulating device to control the power output of a single 12 volt DC glowplug, as in diesel engine automotive heating element. the application is for a vegetable oil conversion on my dodge diesel. my grease is getting safely up to 160*F at the heat exchanger, but there is still a length of tubing with cool grease between exchanger and injection pump, that has to be inducted during initial switch over that may eventually cause issues.
the heating element will also serve as a redundant last chance temp booster in the event that my coolant system just isnt up to the task on extremely cold massachusetts days. i will be machining a simple aluminum block with a provision for threading the glowplug into it, that has separate passages for fuel. the block will be directly grounded and the glowplug should probably be powered by an ignition switch activated relay so that cheap, low power switches can be used, and also to prevent drained batteries from forgetting to turn the unit off. i also have to be able to manually switch it off when diesel fuel is flowing through, heating that reduces lubricity for the injection pump.
i will be using an autometer electronic temp sender and gauge to monitor temperature of the device so no fancy readout or anything is required. the circuit must have the ability to self regulate, because the vegetable oil temperature will increase as the heat exchanger takes effect and raises the oil temp.
please assume that my electronics knowledge doesnt go far beyond E/I/R
thanks for any help.
mike