Abstract: A misfire detection apparatus for an internal combustion engine is capable of detecting combustion when an ionic current generated upon combustion is superimposed on a leakage current, even if the ionic current does not contain an increased component. An ionic current detection part (1) detects an ionic current flowing between electrodes arranged in a combustion chamber of the internal combustion engine through ions generated upon combustion of an air fuel mixture therein by impressing a voltage on the electrodes. A tendency recognition part (4-7) recognizes a tendency of a change in the ionic current detected by the ionic current detection part. A threshold determination device (8) sets a threshold for an output of the tendency recognition part. A determination device (10) determines an occurrence of combustion or misfiring in the combustion chamber based on an output of the tendency recognition part and an output of the threshold determination device.

Abstract: A compressor includes a compression mechanism part for compressing refrigerant sucked from an outside of the hermetic container and discharging compressed refrigerant to a discharge space, an electric motor part composed of a stator and a rotor, facing a first space which is at an opposite side of the discharge space with respect to the compression mechanism part in the hermetic container, for driving the compression mechanism part through a main shaft, a passage at an external circumferential side of the compression mechanism part, for connecting the discharge space with the first space, and a fan provided at an end of the rotor, facing the first space. The refrigerant discharged into the discharge space passes through the passage at the external circumferential side of the compression mechanism part to reach the first space, and passes the fan to be discharged to the outside of the hermetic container.