Abstract: A process for producing silicon carbide short fibers comprises oxidizing metallic silicon powder in an oxidizing gas atmosphere into silicon monoxide in the form of ultrafine particles or gas, and carbonizing said silicon monoxide in a reducing gas atmosphere containing carbon at temperatures being lower than temperatures for producing powder and falling in a temperature range for causing a heterogenous core formation of silicon carbide, thereby producing silicon carbide short fibers. The process of the present invention is capable of mass-producing silicon carbide short fibers continuously in a short time.

Abstract: An air/fuel ratio detector constructed of first and second elements positioned such that the gap between the closed end of the second element constructing the limit current type oxygen sensor and the end of a tubular heater is closed or such that the one of electrodes formed on the second element and located on the side contacting the exhaust gas is made of a material having no catalytic capability to purify the exhaust gas. As a result, the second element does not constitute a concentration cell so that the output characteristics obtainable are ideal from the rich to lean range of the air-fuel ratio.

Abstract: An air-fuel ratio detector and an air-fuel ratio measuring method for detecting an oxygen density in an exhaust gas emitted from the internal combustion engine of an automobile. The air-fuel ratio detector has a tubular body and a pair of partition members dividing the tubular body into a closed-end section and an open-end section. At least one of the partition members comprises a solid electrolyte permeable to oxygen ions. A pair of electrodes is mounted on opposite surfaces of the solid electrolyte and connected to a DC power supply, thus constituting an oxygen pump. Another pair of electrodes is mounted on one of the partition members and connected to a DC power supply, thus constituting a limited-current oxygen sensor. Oxygen is introduced into a space between the partition members at all times by the oxygen pump to maintain the gas, which has been supplied through a gas dispersion member into the space, lean.

Abstract: A detector and a measuring method for detecting an air-fuel ratio in an internal combustion engine or the like. The detector has a tubular body having a closed end, a solid electrolyte permeable to oxygen ions which divides the interior of the tubular body into a closed-end section and an open-end section, and electrodes mounted on opposite surfaces of the solid electrolyte. One pair of the electrodes on the opposite surfaces of the solid electrolyte is connected to a circuit for detecting an electromotive force, thus constituting an oxygen sensor. The other electrode pair is connected to a DC power supply, thus constituting an oxygen pump. The oxygen sensor detects the quantity of oxygen in a gas supplied through a gas dispersion member. The direction of flow and magnitude of and electric current in the oxygen pump are controlled on the basis of an output from the oxygen sensor for enabling the gas to have a stoichiometric air-fuel ratio.