Abstract: A cylinder head structure for a V-type engine comprising a pair of cylinder head members which are the same in shape and oriented in opposite directions and which are provided in each of the front and rear end wall portions with an opening. Camshafts are supported for rotation in the respective cylinder head members so that their respective one ends project outside through the openings on the same end of the engine. A cam pulley is mounted on the projecting portion of each cam shaft, and a transmission belt is provided for transmitting the driving force of the crankshaft to the cam pulley on each camshaft. A pair of first cover members are mounted on the end wall portions of the respective cylinder head members through which the camshafts project to form closed cross section spaces together with the corresponding cylinder head members for covering the transmission belt.

Abstract: An intake arrangement for an internal combustion engine provided with a intake construction capable of generating a swirl effective for improving combustibility within a combustion chamber during low load operating conditions of the engine, without substantially altering a two intake port system aiming at a high output of the engine.

Abstract: A camshaft driving system for a DOHC engine having a pair of cylinder rows which are displaced from each other in the axial direction of the crankshaft so that a vacant space is formed in front of one of the cylinder rows and behind the other cylinder row. One of the camshafts in each cylinder row is provided with a timing pulley. The timing pulleys of the respective cylinder rows are arranged to be driven by the crankshaft of the engine by way of transmission means such as a chain or a timing belt passed around a crank pulley fixed to the crankshaft and the timing pulleys. The driving force transmitted to said one of the camshafts in each cylinder row is further transmitted to the other camshaft in each cylinder row by way of a driving force transmission means.

Abstract: An intake system for a V-type engine comprises a surge tank, a common intake pipe upstream of the surge tank and a plurality of discrete intake pipes for connecting the respective cylinders in the cylinder banks of the V-type engine with the surge tank. Each of the discrete intake pipes for the cylinders in each cylinder bank comprises a U-shaped bight portion which projects from the side of the surge tank remote from the cylinder bank toward the other cylinder bank and is bent toward the cylinder bank, and a crossing portion which is connected between the corresponding intake port in the cylinder bank and the downstream end of the U-shaped bight portion and crosses the discrete intake pipes for the cylinders in the other cylinder bank below the surge tank.

Abstract: In a cylinder block for an internal combustion engine, a pair of opposed side walls thereof extending in the direction of the row of cylinders therein are respectively formed of a plurality of bight portions. The bight portions in each side wall differ in phase from those in the other side wall.

Abstract: An intake arrangement for an internal combustion engine, including a plurality of intake ports opening into a combustion chamber, a plurality of intake valves for opening and closing the intake ports, respectively, a main intake passage having a plurality of branch intake passages connected to the intake ports, respectively, a shutter valve for opening and closing the main intake passage, and an auxiliary intake passage branched from the main intake passage and connected to one of the intake ports.

Abstract: An improved, compact auxiliary mechanism driving device in a V-type, overhead-camshaft engine in which a driving section for engine auxiliary mechanism is mounted on a camshaft without increasing the overall size of the engine by utilizing a vacant or unused space(s) on the camshafts peculiar to such an overhead-camshaft engine. A pair of first and second cylinder banks are arranged in V-shape and have a first and a second cylinder head, respectively. The cylinders of the first bank are displaced from the cylinders of the second bank in the axial direction of the camshaft. A first camshaft having first valve-operating cams for the first cylinders is provided on the first cylinder head of the first cylinders. A second camshaft having second valve-operating cams for the second cylinders is provided on the second cylinder head of the second cylinders.

Abstract: A crankcase ventilating system for a V-type, OHC internal combustion engine comprising a substantially hollow engine body structure having a pair of upwardly diverging cylinder banks and an oil pan secured to the body structure from below to define a crankcase, and also having a pressure buffer chamber, defined between the cylinder banks, at least one engine cylinder, defined in each of the cylinder banks, and a cam chamber defined therein at top of each of the cylinder banks, and an intake system for the introduction of a controlled combustible air-fuel mixture into the engine cylinders. The system comprises first separate oil return passages each defined in the body structure and communicating between the respective engine cylinder and the buffer chamber, and a connecting passage communicating between the buffer chamber and the crankcase.

Abstract: A V-type engine comprises a cylinder block forming first and second cylinder banks arranged in V-shape. Each cylinder bank is provided with a row of cylinders extending in the axial direction of the crankshaft between the front and rear ends of the engine. The cylinder row in the second cylinder bank starts from a location spaced apart from the front end of the engine and the cylinder row in the first cylinder bank starts from a location near the front end of the engine so that the cylinder row in the second cylinder bank is axially rearwardly displaced from that in the first cylinder bank. A water pump is mounted on the front end of the cylinder block substantially at the center between the first and second cylinder banks. A coolant inlet-passage to the water pump is provided in the part of the cylinder block between the foremost cylinder in the second bank and the front end of the cylinder block, which part is a dead space.

Abstract: A V-type internal combustion engine having cam shafts respectively provided in first spaces defined between cylinder heads and head covers of a pair of upwardly diverging cylinder banks and a breather arrangement which includes a pressure buffer chamber provided between the cylinder banks of a cylinder block and having side walls constituted by cylinder block walls of said cylinder banks so as to be closed at its upper portion and communicated with an interior of a crankcase, and a communicating passage for communicating said pressure buffer chamber with an intake passage at a downstream of a throttle valve, and a baffle plate provided in said pressure buffer chamber to confront the open end of said communicating passage.

Abstract: Internal combustion engine having an intake port formed in cylinder head and a first and second intake passages both connected with said intake port. The intake passages are respectively provided with throttle valves and the throttle valve in the second intake passage is opened only under a heavy load operation. The ignition timing is advanced when the throttle valve in the second intake passage has been brought into operation.

Abstract: An exhaust gas recirculation system has at least two recirculation lines to permit recirculation of a large quantity of exhaust gas when required and in which recirculation of exhaust gas is reduced or completely cut off in accordance with particular engine operating conditions.

Abstract: Internal combustion engine having an intake port formed in cylinder head and first and second intake passages both connected with the intake port. The intake passages are respectively provided with throttle valves and the throttle valve in the second intake passage is opened only under a heavy load operation. The ignition timing is advanced or an additional supply of fuel is provided in the transient period wherein the throttle valve in the first intake passage has reached substantially fully open position and the throttle valve in the second intake passage has started to open so as to supplement any decrease in the engine output in this period.

Abstract: An exhaust gas recirculation device in which exhaust gas from the engine of a vehicle, for example, may be recirculated via two separate lines to portions of a carburetor which are upstream and downstream of a throttle valve, to permit a suitably large amount of exhaust gas to be recirculated when necessary and which includes control means which stops the flow of gas in both lines when the engine is being warmed up, and stops the flow of gas in the upstream recirculation line only when engine load, engine speed, or vehicle speed is high, or when there is a risk of icing in the carburetor, whereby the disadvantages of recirculated exhaust gas during particular engine operating conditions are avoided.