Abstract: The phenomenon of resonance in a catalyst converter due to a flow of an exhaust gas is reduced without causing problems with vehicle layout, problems with manufacturing (higher manufacturing cost), or adverse influences on other facets of performance. An internal combustion engine includes an internal combustion engine main body having a fuel chamber formed in an interior, and a catalyst converter arranged in an exhaust flow channel of the internal combustion engine main body and provided with a catalyst for purifying the exhaust gas. The exhaust flow channel, which is upstream of the catalyst of the catalyst converter, is provided with a protuberance for disturbing the flow of the exhaust gas in the exhaust flow channel to reduce pressure pulsations of the exhaust gas.

Abstract: The phenomenon of resonance in a catalyst converter due to a flow of an exhaust gas is reduced without causing problems with vehicle layout, problems with manufacturing (higher manufacturing cost), or adverse influences on other facets of performance. An internal combustion engine includes an internal combustion engine main body having a fuel chamber formed in an interior, and a catalyst converter arranged in an exhaust flow channel of the internal combustion engine main body and provided with a catalyst for purifying the exhaust gas. The exhaust flow channel, which is upstream of the catalyst of the catalyst converter, is provided with a protuberance for disturbing the flow of the exhaust gas in the exhaust flow channel to reduce pressure pulsations of the exhaust gas.

Abstract: Disclosed is a gas compressor capable of preventing generation of noise due to the vibration during the rotation of the rotor. A rotor rotating in a cylinder around a rotation shaft has five radially extending vane grooves, each of which supports a vane. The respective directions of the vane grooves are determined such that the respective angular differences between at least three adjacent compression chambers are not less than 5 degrees. Thus, the angular intervals in terms of direction between the vanes supported by the vane grooves are also different from each other. As a result, the timing with which the vanes pass the outlet port is irregular, and the discharge period is thus unequal between a plurality of compression chambers, whereby the periodicity of the vibration based thereon is reduced, and the peak values of the basic vibration component are reduced.

Abstract: An electromagnetic clutch having an electromagnet, a rotational member mounted to undergo rotation, an armature selectively coupled to the rotational member for rotation therewith when the electromagnet is energized, and a ball bearing rotatably supporting the rotational member. The ball bearing has an inner race, an outer race, and a plurality of balls arranged in a plurality of rows each containing an odd number of the balls. The balls of the ball bearing are disposed between the inner race and the outer race so that each of the balls contacts the inner race at at least one point and contacts the outer race at at least one point.

Abstract: Disclosed is a gas compressor capable of preventing generation of noise due to the vibration during the rotation of the rotor. A rotor rotating in a cylinder around a rotation shaft has five radially extending vane grooves, each of which supports a vane. The respective directions of the vane grooves are determined such that the respective angular differences between at least three adjacent compression chambers are not less than 5 degrees. Thus, the angular intervals in terms of direction between the vanes supported by the vane grooves are also different from each other. As a result, the timing with which the vanes pass the outlet port is irregular, and the discharge period is thus unequal between a plurality of compression chambers, whereby the periodicity of the vibration based thereon is reduced, and the peak values of the basic vibration component are reduced.

Abstract: An electromagnetic clutch is offered to reduce noise and vibration caused from the ball bearing. The number of balls per row of a ball bearing of an electromagnetic clutch is given an odd number.