Abstract: A cylinder head includes an intake throat and an intake duct, a valve seat ring is provided in an inner ring of the intake throat; a section of the intake duct is a tumble generating duct; and an extending direction of the tumble generating duct is oblique relative to the cylinder head bottom surface, the lower side surface of the tumble generating duct is a tumble guide surface, the lower end of which forms a tumble generating sharp angle, and the projection of the tumble generating sharp angle on the upper end circular surface of the valve seat ring is a sharp angle projection, the sharp angle projection is a protruding area protruding from the edge of the upper end circular surface of the valve seat ring, and the width of the middle part of the sharp angle projection is larger than the width of both ends thereof.

Abstract: A cylinder head includes an intake throat and an intake duct, a valve seat ring is provided in an inner ring of the intake throat; a section of the intake duct is a tumble generating duct; and an extending direction of the tumble generating duct is oblique relative to the cylinder head bottom surface, the lower side surface of the tumble generating duct is a tumble guide surface, the lower end of which forms a tumble generating sharp angle, and the projection of the tumble generating sharp angle on the upper end circular surface of the valve seat ring is a sharp angle projection, the sharp angle projection is a protruding area protruding from the edge of the upper end circular surface of the valve seat ring, and the width of the middle part of the sharp angle projection is larger than the width of both ends thereof.

Abstract: A weak tumble flow fast combustion system is provided. An intake throat and an exhaust throat are provided on a cylinder head, a section of an intake duct close to the intake throat is a tumble guide duct, an axis of the tumble guide duct is arranged obliquely with respect to the bottom surface of the cylinder head, and an upper side surface of the tumble guide duct is a flowing-down guide surface arranged obliquely with respect to the bottom surface of the cylinder head, a lower side surface of the tumble guide duct is an arc-shaped guide surface recessed toward the bottom surface of the cylinder head, an eccentric chamfer is provided at the lower end of the intake throat, and the eccentric direction of the eccentric chamfer is offset along the direction connecting the center of the intake throat to the exhaust throat.

Abstract: The present application relates to an electronic device and a wireless communication method. The electronic device comprises: a processing circuit, configured to select a modulation codebook from a modulation codebook cluster for use in a multiple-input multiple-output MIMO system on the basis of a channel matrix of the MIMO system, the modulation codebook cluster comprising a plurality of modulation codebooks used by a sending terminal device corresponding to the electronic device for generating modulation signals, wherein the number of data streams transmitted after modulation is greater than the number of orthogonal channels; and a transceiving circuit, configured to send feedback information to the sending terminal device, the feedback information comprising identification information of the selected modulation codebook.