Abstract: A protective circuit capable of remotely switching power to a load on and off and including an electrothermal sensor system having a heating element of predetermined resistance in series with the load and source of power whereby the temperature of the heating element is monitored relative to ambient temperature to determine current flow in the heater. The electrothermal sensor, according to one embodiment, includes a ceramic substrate having the heater formed thereon with a first deposited heat monitoring element thereon for monitoring the temperature of the heater and a second heat monitoring element thereon for monitoring the ambient temperature of the substrate remote from the heater. The electrothermal sensor, according to a second embodiment, includes a layer of electrically conductive material, a backing layer thereon of electrically insulating material, a grid on the backing layer of thermoresponsive material to form RTDs and a second layer of electrically insulating material over said grid.

Abstract: A protective circuit capable of remotely switching power to a load on and off and including an electrothermal sensor system having a heating element of predetermined resistance in series with the load and source of power whereby the temperature of the heating element is monitored relative to ambient temperature to determine current flow in the heater. The electrothermal sensor, according to one embodiment, includes a ceramic substrate having the heater formed thereon with a first deposited heat monitoring element thereon for monitoring the temperature of the heater and a second heat monitoring element thereon for monitoring the ambient temperature of the substrate remote from the heater. The electrothermal sensor, according to a second embodiment, includes a layer of electrically conductive material, a backing layer thereon of electrically insulating material, a grid on the backing layer of thermoresponsive material to form RTDs and a second layer of electrically insulating material over said grid.

Abstract: A cylinder pressure transmitter has piezoelectric means to provide an electrical signal corresponding to pressure in a cylinder of an automotive internal combustion engine during engine operation and has electronic means to amplify the signal for transmission to computer control means for use in regulating spark advance to improve engine efficiency and performance and reduce engine knocking. The pressure transmitter has a generally cylindrical body having a chamber open at both ends for attachment to an engine cylinder, has a diaphragm secured over one end of the chamber, and has the piezoelectric means held against the diaphragm with a selected preload compressive force by backing means which are threadedly engaged with the body inside the chamber for adjustment to provide the desired force.

Abstract: A fuel system for an internal combustion engine has an electrical resistance heater accommodated in gasket means disposed between a throttle body flange and a mating flange on an intake manifold so that the heater is located immediately adjacent an idling speed fuel inlet nozzle or the like in the throttle body for transferring heat to the nozzle area through the throttle body flange to prevent freeze-up of the nozzle during engine operation.

Abstract: An economical mirror unit adapted for exterior mounting on an automobile has a single self-regulating electrical resistance heater disc of a material of positive temperature coefficient of resistivity mounted in a recess on a heat-distributing metal plate and enclosed in the recess by a glass reflecting member mounted over the recess so that the heater serves to defog the reflecting surface of the member. Various portions of the plate have selected different spacings from the glass reflecting member for heating various overlying portions of the reflecting member to a substantially uniform temperature so that the heater is operable at a high temperature to rapidly and uniformly defog the mirror without risk of damage to the glass reflecting member.