Abstract: An output voltage from an O.sub.2 sensor is intermittently sampled and the sampled voltage is converted into a binary signal. The binary signal is applied to an electrical digital computer, and therein the following operations are carried out. First, the maximum and minimum values of the applied binary signal are detected, then the difference between the detected values is calculated. Thereafter, the calculated difference is compared with a predetermined value to generate a binary signal indicative of the comparison result. The air-fuel ratio feedback control responsive to the applied binary signal is executed when the binary comparison result signal indicates that the calculated difference is larger than or equal to a predetermined value.

Abstract: A method for controlling an internal combustion engine with a fuel injection valve fitted to its intake manifold. Repeatedly a first quantity representing the desired amount of fuel to be supplied to the combustion chambers in the next fuel injection pulse, a second quantity representing the proportion of fuel in one pulse which will adhere to the walls of the intake system, and a third quantity representing the proportion of fuel adhering to these walls which will be sucked off into the combustion chambers between two successive pulses are determined, based upon sensed values of certain operational parameters.

Abstract: A novel pectin esterase which randomly hydrolyzes the methyl ester bond of pectin can be obtained by cultivating, on a medium, a mold strain belonging to Genus Aspergillus, Genus Penicillium, Genus Fusarium or Genus Sclerotinia and having an ability to produce said novel pectin esterase. A demethoxylated pectin having a uniform methoxyl group content can be obtained by adding said novel pectin esterase to pectin. The demethoxylated pectin thus obtained can be utilized as gelling agent, emulsifier or thickener for food processing.

Abstract: An oxygen sensor which comprising: a case having an inlet means and an outlet means through which gas passes. A sensor element is installed within the case, and an oxidation catalyzer is arranged upstream of said sensor element within said case. The inlet means or oxidation catalyzer is arranged so that a part of the gas which is introduced through the inlet means into the case flows without passing through the oxidation catalyzer while the other part of said gas passes through the oxidation catalyzer.