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.

Abstract: A carburetion system for providing improved cold start engine operation comprises a carburetor having an air-fuel passage, an air inlet to the passage, a fuel inlet to the passage for mixing fuel and air in the passage, and an outlet from the passage for delivering a mixture of air and vaporized fuel to the engine. A heater comprising a ceramic resistor body of a material of positive temperature coefficient of resistivity has a plurality of passages extending through the body and has means directing electrical current through the body for heating the body. The heater is mounted at the outlet of the air fuel passage of the carburetor with the heater body passages aligned with the air-fuel passage to pass the air-fuel mixture through the heater passages in heat-transfer relation to the body to facilitate vaporization and mixing of the fuel in the air-fuel mixture.

Abstract: A resistor particularly useful as a self-regulating fluid heater has passages extending through a body of ceramic resistance material of positive temperature coefficient of resistivity (PTC) and has ohmic contact coatings formed on the inner walls of the passages. The passage walls define thin webs of the resistance material between adjacent passages and are of uniform thickness end to end. Slits located in the walls at the ends of selected passages accommodate electrically conducting means which interconnect the contacts in selected pairs of the passages. In that way, predetermined groups of the contacts are interconnected at respective ends of the resistor so that when the groups of contacts are connected in a circuit, electrical current is directed through the thin webs of resistance material between contacts of opposite polarity in adjacent passages, thereby to heat the resistor to self-regulate its temperature to efficiently generate heat for transfer to a fluid directed through the passages.

Abstract: An automatic choke system of modular construction has self-regulating heaters arranged to heat a thermostatic spring to adjust a choke valve during start-up of an automotive engine. Heat storing and transferring means are located between the heaters and spring to provide heat-transfer paths of different lengths between the respective heaters and the spring for providing the thermostatic spring with non-linear heat up to improve the smoothness of initial engine operation while also minimizing the period of fuel-enriched operation during start-up. The same heat storing and transferring means is also provided with a large heat storing capacity for continuing to transfer heat to the spring after termination of engine operation to prevent any substantial fuel enrichment by the choke system if the engine should be restarted before selected portions of the engine cool below selected fuel vaporizing temperatures.

Abstract: A mirror unit suitable for exterior mounting on an automobile includes a glass member with a reflecting surface, a thermally-conducting metal plate, a self-regulating electrical resistance heater body of material of positive temperature coefficient of resistivity having one side mounted on one side of the plate in thermally and electrically conducting relation to the plate, terminal means electrically connected to the opposite side of the heater body, and means securing the plate to the glass member for enclosing the heater body therebetween to heat the glass member for defogging the reflecting surface thereof.

Abstract: A carburetion system for providing improved cold start engine operation comprises a carburetor having an air-fuel passage, an air inlet to the passage, a fuel inlet to the passage for mixing fuel and air in the passage, and an outlet from the passage for delivering a mixture of air and vaporized fuel to the engine. A heater comprising a ceramic resistor body of a material of positive temperature coefficient of resistivity has a plurality of passages extending through the body and has means directing electrical current through the body for heating the body. The heater is mounted at the outlet of the air-fuel passage of the carburetor with the heater body passages aligned with the air-fuel passage to pass the air-fuel mixture through the heater passages in heat-transfer relation to the body to facilitate vaporization and mixing of the fuel in the air-fuel mixture.

Abstract: A carburetion system for improving cold starting of an automotive engine comprises a carburetor having an air-fuel passage, an air inlet to the passage, a fuel inlet to the passage for mixing fuel and air in the passage, and an outlet from the passage for delivering a mixture of an air and vaporized fuel to the engine. A heater comprising a ceramic resistor body of a material of positive temperature coefficient of resistivity has a plurality of relatively large passages extending in a pattern in spaced side-by-side relation to each other through the body between opposite ends of the body for defining thin webs of the resistor material between adjacent body passages. The heater is mounted at the outlet of the carburetor air-fuel passage with the heater passages aligned with the air-fuel passage to pass the air-fuel mixture through the heater passages in heat transfer relation to the body.

Abstract: A condition responsive control device is disclosed for affecting operation of a choke control in response to variable ambient and system temperatures, as well as the use of such a device in a system in which it is desired to adjust an operating parameter of the system in response to such temperatures. The device includes an ambient temperature sensing switch which remains de-energized in response to ambient temperatures below a first preselected temperature level and is energized in response to temperatures in excess of this level so as to transmit an electrical signal in response to energization. The device also includes a system temperature sensing thermostatic coil which remains unactuated in response to system temperatures below a second preselected temperature level and is actuated in response to temperatures above this level so as to effect an operating parameter of the system.