Mazda Motor Corporation

Naohide Koshimoto

Shigeki Nakatani

Keiji Araki

Hiroyuki Sugimoto

A particular cooling water passage structure is installed in a V-type engine having two cylinder banks offset in a lengthwise direction of a crankshaft. Each bank is provided with inlet ports, provided to admit a cooling water flow. Each inlet port communicates with a lengthwise front end portion of the water jacket. The inlet port of one of the cylinder banks, which is offset forward relative to the other, is further in communication with a side portion, adjacent to the front end portion, of the water jacket. The inlet ports have apertures which open at the same location in the lengthwise direction. Piping, connected to the inlet ports, is provided in a space formed between the offset cylinder banks.

Cooling water passage for V-type internal combustion engine

An overhead camshaft structure for a double overhead camshaft engine having at least three in-line cylinders and two camshafts which are formed with series of pairs of cam lobes and series of camshaft journals, respectively, and are operatively connected with each other by helical gears comprises a thrust collar formed on each camshaft, a thrust bearing formed with a thrust restrictive groove consisting of an upper half and a lower half, narrower than the upper half, for receiving therein the thrust collar, and an oil passage consisting of a radial passage portion penetrating through the thrust collar and an axial passage portion formed in each camshaft for allowing oil to pass up to each cam lobe and camshaft journal for lubrication. The radial passage is directed in parallel with a straight line connecting an axial centerline of rotation of each said camshaft and a juncture of a valve opening ramp of said cam lobe adjacent to said thrust collar.

Camshaft structure for double overhead camshaft engine

A V-type DOHC engine has first and second banks. The end of the cylinder row in the first bank on one end of the engine retracts from that of the cylinder row in the second bank. A first camshaft in each bank is driven by the crankshaft by way of a first transmission mechanism which is disposed on said one end of the engine, and the first and second camshafts in each bank are connected by a second transmission mechanism which is disposed between the first transmission mechanism and the cylinder row of the bank. The end portion of the first camshaft in the first bank on said one end of the engine is supported by a pair of bearings one disposed between the first and second transmission mechanisms and the other disposed between the second power transmission mechanism and the cylinder row in the first bank. The end portion of the second camshaft in the first bank on said one end of the engine is supported by a bearing disposed between the second transmission mechanism and the cylinder row in the first bank. The end portion of each of the camshafts in the second bank on said one end of the engine is supported by a bearing disposed between the first and second transmission mechanisms.

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Hiroshima, Japan

Naohide Koshimoto