Mazda Motor Corporation

Tetsuo Hiraoka

Koichi Hatamura

Shinji Seike

Kazuaki Hokazono

Kouichi Hatamura

Koji Asanomi

Tomohiro Sunada

Yasuhiro Kawasako

Takenori Ohtsuka

Takenori Otsuka

Sigeyasu Yamamoto

Minoru Akizuki

Muneyuki Ogami

A V-type engine has a plurality of cylinders formed in a pair of cylinder banks. An intake system for the V-type engine includes a surge tank which is communicated with the atmosphere through a common intake passage provided with a throttle valve, discrete intake passages which branch off from the surge tank and are connected to the responsive cylinders, branch passages which branch off from the respective discrete intake passages, one or more volume chambers each of which is communicated with at least two of the branch passages, on-off valves which are respectively provided in the branch passages and are opened and closed according to the operating conditions of the engine. The surge tank is disposed above one of the cylinder banks and the volume chamber or volume chambers are disposed above the other cylinder bank.

Intake system for V-type engine

An intake system includes two surge tanks for cylinders in first and second cylinder banks of a V-type internal combustion engine which are arranged side by side over one of the first and second cylinder banks in the lengthwise direction of its associated engine and, are preferably formed as one unit and includes intake passages arranged in series in the lengthwise direction, each intake pipe connecting the surge tank with each of the cylinders in the first and second cylinder banks. The outermost intake passages disposed at the opposite ends of the surge tanks extend outward of the surge tanks in the opposite directions and are bent back into a space between the first and second cylinder banks. The remaining intake passages for the cylinders in the first cylinder bank are of C-shaped passage and the remaining intake passages for the cylinders in the second cylinder bank cross inside the C-shaped intake pipes in the space.

Intake system for V-type vehicle engine

An air suction device for a multicylinder engine comprises a first group of inlet passages each having one end connected to one of a first group of cylinders, a second group of inlet passages each having one end connected to one of a second group of cylinders, a surge chamber separated off by a partition-wall into first and second compartments for air expansion provided with a plurality of first openings each coupled with the other end of one of the first group of inlet passages and a plurality of second openings each coupled with the other end of one of the second group of inlet passages, respectively, and a valve unit including a body member forming an air passage and a closing valve disposed in the body member for closing selectively the air passage. The partition-wall is provided with a cutout portion thereon, and the valve unit is fitted to the cutout portion provided on the partition-wall in the surge chamber so as to form with the air passage thereof a connecting passage provided for interconnecting the first and second compartments and closed selectively by the closing valve.

Air suction devices for multicylinder engines

This invention relates to an internal combustion engine including a plurality of groups of combustion chambers and at least a first expansion chamber and a second expansion chamber. The first and second expansion chambers extend in a lengthwise direction and are separated from each other by a partition wall. The first expansion chamber is connected with one group of combustion chambers through separate branch passages. The second expansion chamber is also connected with another group of combustion chambers respectively through separate branch passages. First and second intake passages are connected at downstream ends with the first expansion chamber and the second expansion chamber, respectively. An auxiliary communicating passage is provided along the partition wall independent from said first and second intake passages and connects the first and second expansion chambers with each other. A length changing device for alternately communicating the first and second expansion chambers with each other by an auxiliary communicating passage of a minimum length and by an auxiliary communicating passage of a maximum length in accordance with engine operating condition is provided. The first and second intake passages have lengths a sum of which is greater than the maximum length of the auxiliary communicating passage.

Engine intake system

An induction system for a V-type internal combustion engine having a first and second banks respectively constituted with a plurality of cylinders and shifted with respect to each other in the direction of alignment of the cylinders, including intake ports provided to face a space between two banks, surge tank means for leading intake air to each intake port arranged above one of the banks, first intake passage means curvedly formed for feeding intake air from the surge tank means to the cylinders of the first bank, each being connected with the side portion of the surge tank means at one end thereof and with one of the intake ports of the cylinder of the first bank at the other end thereof and consisting of an upstream intake passage means and a downstream passage means, and second intake passage means curvedly formed for feeding intake air from the surge tank means to the cylinders of the second bank, each being connected with the side portion of the surge tank means at one end thereof and with one of the intake ports of the cylinder of the second bank and consisting of an upstream intake passage means and a downstream intake passage means, said first intake passage means being connected with the surge tank means at a point higher than a point where the second intake passage is connected with the surge tank means.

Induction system for V-type internal combustion engine

In an intake system for a V-type engine having a plurality of cylinders in each of first and second cylinder banks, a plurality of intake ports each of which is communicated with one of the cylinders being open in the inner surfaces of the cylinder banks opposed to each other, an intake manifold structure for forming discrete intake passages which are separately communicated with the respective intake ports to introduce intake air into the cylinders corresponding thereto comprises first and second pieces. The first piece is provided with a plurality of passages each forming one of said discrete intake passages communicated with the intake ports of the first cylinder bank and a connecting portion for integrally connecting the passages at a portion near the first cylinder bank. The second piece is provided with a plurality of passages each forming one of said discrete intake passages communicated with the intake ports of the second cylinder bank and a connecting portion for integrally connecting the passages at a portion near the second cylinder bank. The first and second pieces are fastened together so that the passages of the first and second pieces are alternately positioned in the direction of the row of the cylinders and cross each other between the first and second cylinder banks.

Intake manifold structure for V-type engine

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.

In an intake system for a multicylinder engine, discrete intake passage portions immediately connected to the respective cylinders are divided into two groups so that intake timings of the discrete intake passage portions in each group are not immediately successive, and the discrete intake passage portions in each group are concentrated to form a concentrated portion. Branch intake passage portions extend upstream from the concentrated portions for the both groups and are integrated with each other to form a main intake passage portion. Bypass air for adjusting the engine rpm during idling, blowby gas from the crankcase, fuel vapors trapped by the canister, exhaust from the exhaust system and the like are introduced into the concentrated portions of the discrete intake passage portions or the branch intake passage portions by way of a fluid introduction passage comprising a pair of branch introduction passage portions which are connected to the respective concentrated portions at one end and to a downstream end of a main introduction passage portion at the other end. The main introduction passage portion is connected to sources of the fluids described above at the upstream end portion. The average length l and the diameter d of the branch introduction passage portions are selected to satisfy the condition

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Hiroshima, Japan

Tetsuo Hiraoka