FR2584455A1 - INTERNAL COMBUSTION ENGINE CYLINDER HEAD WITH THREE VALVES - Google Patents

Abstract

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

Description

i The invention relates to an internal combustion engine cylinder head with

  positive ignition, comprising combustion chambers associated with corresponding cylinders of the engine and in which each combustion chamber is provided with two intake valves and with an exhaust valve suitable for closing two intake ducts and one duct exhaust opening respectively in

  two opposite side faces of the cylinder head.

  The presence of two intake valves per

  combustion chamber not only provides

  rer a relatively large passage section for

  intake gases, and as a result of obtaining an import-

  aunt engine power, but also to provide a variable power supply optimized by introducing intake gases alternately by a single valve

  at low speeds and / or low engine loads

  or by the two valves at high speeds

and / or heavy loads.

  In the usual cylinder heads of this type, the

  two intake valves from each com- part chamber

  bustion are juxtaposed, generally on the side of the lateral face where the intake ducts open,

  and on the opposite side are arranged the exhaust valve

  and a spark plug. The inner end

  of it, provided with electrodes causing the inflammation

  mation of the mixture introduced into the chamber, is consequently significantly spaced from the center of the chamber, close to the exhaust valve, and relatively distant from one of the two intake valves. This often results in incomplete combustion of the mixture and a strong knocking tendency, which results

  by defective engine performance and deterioration

  excessive ration of its mobile crew.

  The invention aims to achieve a cu-

  weary of the suspended type, with three valves per cylinder, providing the engine with good performance and

minimal knocking tendency.

  According to the invention, in each combustion chamber the exhaust valve and a first intake valve are arranged on the side of the side face o opens the exhaust duct, the

  two intake valves are approximately diametra-

  opposite, and the inner end of the spark plug is located between the two intake valves, on the side opposite to the exhaust valve and close to it

from the center of the room.

  According to other advantageous features of the invention: - the valves are driven by an overhead camshaft, by means of two respective pushers for the exhaust valve and for the first intake valve, and by l 'via a rocker arm for the other intake valve; _ the spark plug is screwed into the side face o open the intake ducts, and it is

  arranged in an inclined position under the associated duct

  linked to the first intake valve.

  A non-limiting example of embodiment of a cylinder head according to the invention is described below, with reference to the accompanying drawings, in which: Figure 1 is a view in elevation and in

  section along line I-I of Figure 2 of a breech-

  se of an internal combustion engine according to the invention; - Figure 2 is a top view without cylinder head cover of the cylinder head of Figure 1; - and Figure 3 is a partial view of

  below the cylinder head of Figures 1 and 2.

  We see in the Figures a cylinder head 1 of an internal combustion engine, intended to cover by its underside 2 a cylinder block delimiting

  with pistons several combustion chambers 3.

  In each chamber 3 there are two inlet ducts 4, 5 and an exhaust duct 6 which can be closed off respectively with inlet rod 7, 8 or exhaust 9 valves (hidden by the valve 7 at the

Figure 1).

  At their end opposite to the chamber 3, the intake ducts 4, 5 open into a first lateral face 10 of the cylinder head 1, and the exhaust duct 6 opens into the opposite side 11, communicating respectively with pipes of 'inlet 12 and exhaust 13, In the embodiment shown, the conduits 4 and 5 are separated up to the face 10 and the tube 12 has two orifices to the right of this face. As a variant, the conduits 4 and 5 meet before opening onto the face 10, and the tube 12 then has only one

orifice to the right of this face.

  The intake valve 7 and the exhaust valve 9 are substantially perpendicular to the face 2 and located, above the chamber 3, on the side of the side face 11, and each cooperate with one of two parallel pushers 14, 15 operated

  respectively by a cam 16 and a solid cam 17

  of a shaft 18 carried by the cylinder head 1 parallel

on faces 2, 10 and 11.

  The intake valve 8 is significantly inclined relative to the other two valves 7, 9 and is located, above the chamber 3, on the side of the side face 10, where it cooperates with a rocker arm oscillating on an axis 20 and actuated by a cam 21 of

258445S

4-

  the shaft 18. This axis 20 is carried by several cha-

  bearing skins 22 which hold the shaft 18 on

  transverse partitions 23 of the cylinder head 1.

  Each valve is conventionally returned to its seat by a spring such as those 24 and 25

corresponding to valves 7 and 8.

  A cylinder head cover 26 covers the cylinder head 1 so as to protect the shaft 18 and its bearings 22, the rocker arms 19 and their axis 20 as well as the pushers 14, 15 and the springs. This cylinder head cover is removed

  in Figure 2 to clarify the drawing.

  The camshaft 18 and the rocker shafts being situated relatively high, above the valves 7, 9 and their pushers 14, 15, the conduits 4 and 5

  have large radii of curvature -

  for example greater than 3 cm- and open enough-

  high on side 10 to make room for a bou-

  ignition 30 screwed into cylinder head 1 on the side of

  this face, near valve 8 and below the con-

intake 4.

  The spark plug is relatively slightly inclined relative to the face 2 of the cylinder head 1 and, according to a feature of the invention, its internal end a provided with electrodes is located, in the chamber 3, near the center of the latter , on the side opposite the

  exhaust valve 9 and between the two valves 7.

  8 intake, which are roughly diametrically opposed. This results in satisfactory combustion of the gas mixtures produced in chamber 3 and a minimal knocking tendency, in particular thanks to the good distribution of the gases admitted by the two opposite valves 7, 8 and thanks to the almost central position of the zone of controlled inflammation, while the

  area between the internal end 30a of the bou-

  gie 30 and the exhaust valve 9 is cooled by

  the gases admitted by the two valves 7, 8.

  Furthermore, thanks to their large curvature, the intake ducts 4 and 5 have good permeability, that is to say a low resistance to

  the flow for the gases which pass there, which opti-

  switches on the supply of chamber 3, in particular

  for high engine operating speeds.

445S

Claims (3)

  1 - Cylinder head of internal combustion engine   controlled ignition, comprising combustion chambers   tion (3) associated with corresponding engine cylinders, and wherein each combustion chamber (3) is provided with a spark plug (30), two intake valves (7, 8) and a valve exhaust (9) suitable for closing two intake ducts (4, 5) and an exhaust duct (6) opening respectively   in two opposite side faces (10, 11) of the cu-   exhaust (1), characterized in that, in each combustion chamber (3) the exhaust valve (9) and a first intake valve (7) are arranged on the side of the side face (11) where the exhaust pipe (6), the two intake valves (7,   8) are roughly diametrically opposite, and the former   internal end (30a) of the spark plug (30) is located between the two intake valves (7, 8). on the side opposite to and near the exhaust valve (9) from the center of the chamber (3).   2 - cylinder head according to claim 1, charac-   that the valves (7, 8, 9) are entrained   born by a camshaft (18) at the head, by means of two respective pushers (15, 14) for the exhaust valve (9) and for the first intake valve (7) , and through a   rocker arm (19) for the other intake valve (8).   3 - cylinder head according to one of claims 1   and 2, characterized in that the spark plug (30) is screwed into the lateral face (10) o open the intake ducts (4, 5) and it is arranged, in an inclined position, under the duct (4) associated with the first one intake valve (7).