Abstract: An engine includes a cylinder head, an ignition plug disposed in the cylinder head, a head partition wall disposed on the cylinder head to surround a periphery of the ignition plug, an injector disposed in the cylinder head and having an injection hole exposed outside the head partition wall, a cylinder block coupled to the cylinder head, a cylinder formed in the cylinder block, a piston disposed in the cylinder, and a piston partition wall disposed on a crown surface of the piston to face the head partition wall in a sliding direction of the piston. The height of the piston partition wall from the crown surface on the side closer to the injector is less than the height of the piston partition wall from the crown surface on the side farther from the injector.

Abstract: An engine includes a cylinder head, an ignition plug disposed in the cylinder head, a head partition wall disposed on the cylinder head to surround a periphery of the ignition plug, an injector disposed in the cylinder head and having an injection hole exposed outside the head partition wall, a cylinder block coupled to the cylinder head, a cylinder formed in the cylinder block, a piston disposed in the cylinder, and a piston partition wall disposed on a crown surface of the piston to face the head partition wall in a sliding direction of the piston. The height of the piston partition wall from the crown surface on the side closer to the injector is less than the height of the piston partition wall from the crown surface on the side farther from the injector.

Abstract: A hydrazinopyridazine compound represented by the formula ##STR1## wherein R.sup.1 represents a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a lower alkyl group which may optionally be substituted by a halogen atom or a hydroxyl, lower alkoxy, lower alkylthio, lower alkanoylamino, allyloxy or tetrahydrofurfuryloxy group, a lower alkoxy group which may optionally be substituted by a 2-furyl, phenyl or lower alkoxy group, a lower alkenyl group, a lower alkenyloxy group, or a lower alkynyl group; R.sup.2 represents a hydrogen atom, a halogen atom, a cyano group, a lower alkyl group which may optionally be substituted by a halogen atom or a lower alkoxy group, a lower alkoxy group, a lower alkenyl group, or a lower alkenyloxy group; R.sup.3, R.sup.4 and R.sup.5, independently from each other, represent a hydrogen atom, a halogen atom, a lower alkyl group which may optionally be substituted by a lower alkoxy group, or a lower alkoxy group; R.sup.6 and R.sup.