INTAKE DEVICE FOR INTERNAL COMBUSTION ENGINES

Abstract: In an internal combustion of the type, in which a thin and high speed auxiliary intake air flow is injected into a combustion chamber (1) from an auxiliary intake pipe (16) having a small effective area and being formed in the wall of an intake passage (6) in the vicinity of that combustion chamber thereby establishing an intense swirl in the air-fuel mixture in the combustion chamber an intake device is provided having a deflector (18) formed at the leading end of that auxiliary intake pipe.

Description: Intake Device for Internal Combustion Engines The invention relates to an intake device for internal combustion engines of the type in which an auxiliary intake pipe is provided which is directed towards the inside of a combustion chamber and protrudes into the engine intake passage. Intake devices of the above type make it possible to achieve improved combustion conditions for the air-fuel mixture. In intake devices of the above type the auxiliary intake pipe has a small effective area and by means of a thin and high speed auxiliary intake flow injected from said auxiliary intake pipe said improved combustion conditions in the combustion chamber are achieved by establishing a high speed swirl in that combustion chamber. Combustion chambers which are used in connection with auxiliary intake pipes of the-above type have their vertical walls extending in parallel with the cylinder axis. As outlined above, said auxiliary intake pipes protrude into the intake passage and if one of the af ore-mentioned vertical combustion chamber walls happens to be located in front of the injection direction, the auxiliary intake air flow injected from said auxiliary intake pipe impinges upon said vertical combustion chamber wall resulting in a scattering of said intake air flow so that the desired swirl cannot be established. The invention as claimed is intended to remedy these drawbacks. It solves the problem of how to design an intake device for internal combustion in which a high speed swirl can be established in the air-fuel mixture in the combustion chamber even if a vertical combustion chamber wall is located in front of the auxiliary intake air outlet. According to the invention an intake device for internal combustion engines comprising an auxiliary intake pipe which protrudes into an intake passage in the vicinity of an combustion chamber is characterised in that a deflector is provided at the leading end of that auxiliary intake pipe to deflect the air-flow from that auxiliary intake pipe. The advantages offered by the invention are mainly that the auxiliary intake air flow injected from that auxiliary intake pipe does not impinge upon a vertical wall. Since the auxiliary air flow is deflected by the inventive deflector provided at the leading end of the auxiliary intake pipe, there can be attained an effect that the increase in the intake resistance can be reduced, as compared with intake devices of the type in which the auxiliary intake pipe is bent or crushed in the intake passage. Moreover, since the deflector is disposed in the vicinity of the leading end of the auxiliary intake pipe, there can be attained another effect in that the injection p rt of the auxiliary intake pipe is located inthe vicinity of the intake valve so that the auxiliary intake flow is not blocked from passing through the opened clearance of the intake valve even if it is relatively high-deflected. According to a preferred embodiment of the invention said deflector is attached to the upper wall of said auxiliary intake pipe. According to a further improvement of the present invention said deflector is formed by an extension of the leading edge of the upper wall of that auxiliary intake pipe. In accordance with another preferred embodiment of the invention said deflector is of spoon-like shape or of tongue like shape. One way of carrying out the invention is described in detail below with reference to drawings which illustrate only one specific embodiment, in which: Fig. 1 is a schematic side view showing an intake assembly in partial section, Fig. 2 is a section taken along line II - 1I of Fig. 1, Fig. 3 is a perspective view showing the leading end of an auxiliary intake pipe which is located in the vicinity of an intake valve, Fig. 4a is a detailed side view showing the leading end of the auxiliary intake pipe and Fig.4b is a front view of the leading end shown in Fig. 4a. As shown in Figs. 1 and 2 the inventive intake device is associated with a combustion chamber 1 of bath tub shape. Said combustion chamber is defined by a cylinder 2 having a vertical inner cylinder wall 2a, a cylinder head 3 and a piston 4. An intake passage 6 leading to the combustion chamber 1 through an intake valve 5 has communication with the atmosphere through a valve housing 7 attached to the cylinder head 3, an intake manifold 8, an insulator 9 and a carburetor 11. This carburetor II is of well-known type and is equipped with two throttle valves, namely an operator operated throttle valve 12 in the carburetor primary passage 11a and an automatic throttle valve 13 in the carburetor secondary passage 11b. The construction thus far described is substantially similar to that of the well-known intake assemblies except valve-housing 7. Within intake passage 6 a control valve 14 is provided which is made cooperative with the operator operated throttle valve 12 but is opened with a slight delay as compared to said throttle valve 12. Control valve 14 is however fully opened substantially simultaneously with throttle valve 12. The intake passage 6 is branched between the throttle valves 12 and 13 and the control valve 14, i.e., at the branches 8a (Fig. 2) of the manifold 8, thereby forming auxiliary intake passages 15. These auxiliary intake passages 15 have their downstream sides formed into auxiliary intake pipes 16 which are press-fitted in and supported by the valve housing 7. Reference numeral 17 indicates a balancing passage which establishes communication between the auxiliary intake passages of the respective cylinders and which acts as a distributing passage 9a for EGR gases (exhaust gas return). Each of the injection ports, that is, each of the leading ends of the auxiliary intake pipes 16 is provided, as shown in Figs. 3 and 4 with a spoon-shaped or preferably tongue-shaped deflector 18. This deflector 18 is attached to the upper wall of the auxiliary intake pipe 16 thereby to deflect the air flow from that auxiliary intake pipe 16 downwards so that it may not impinge upon the wall of the combustion chamber of the cylinder head 3. The deflector 18 may be formed by an extension of the leading end of the upper wall of that auxiliary intake pipe. The operation of an internal combustion engine having an intake device as described above will be illustrated in the following. In light load operation of the engine including the idling operation, the control valve 14 is closed so that the intake air is completely fed through the auxiliary intake passages 15. More specifically, when the intake valves 5 are opened, the vacuum in combustion chambers 1 is propagated into the intake passages 6 such that the auxiliary intake air flows in a thin and high speed air flow, which is directed tangentially of cylinder wall 2a, into the combustion chambers 1. The incoming auxiliary intake air flow is deflected downwardly when passing the inventive deflector 18 so that instantly an intensive swirl is established at the cylinder axis without impinging upon the walls of the cylinder head 3. The inventive intake device is suitable for combustion chambers having a bath tub shape, a wedge shape or the like which has its vertical wall extending in parallel with the cylinder axis. As has been described hereinbefore the present invention provides an intake device for internal combustion engines in which an auxiliary intake pipe is provided having a small effective sectional area and being directed towards the inside of a combustion chamber. Said auxiliary intake pipe protrudes into the intake passage of the engine so that a high speed swirl may be established in the airfuel mixture of the combustion chamber by a thin and high speed auxiliary intake flow injected from the auxiliary intake pipe.

Claims: Claims: 1. Intake device for internal combustion engines comprising an auxiliary intake pipe (16) which protrudes into an intake passage (6) in the vicinity of an combustion chamber (1), characterised in that a deflector (18) is provided at the leading end of said auxiliary intake pipe (16) to deflect the air flow from said auxiliary intake pipe downwardly. 2. Intake device as claimed in claim 1, characterised in that said deflector (18) is attached to the upper wall of that-auxiliary intake pipe (16). 3. Intake device as claimed in claim 1, characterised in that said deflector (18) is formed by an extension of the leading end of the upper wall of said auxiliary intake pipe (16). 4. Intake device as claimed in one of claims I to 3, characterised in that said deflector (18) is of spoonlike shape. 5. Intake device as claimed in one of claims 1 to 3, characterised in that said deflector (18) is of tonguelike shape. CLAIMS: 1. Intake device for internal combustion engines comprising an auxiliary intake pipe (16) which protrudes into an intake passage (6) in the vicinity of a combustion chamber (1) characterised in that to the upper wall of said auxiliary intake pipe (16) there is attached a deflector (18) of spoon-like or tongue-like shape, to deflect the air flow from that auxiliary intake pipe so that it may not impede upon the wall of the combustion chamber (1). 2. Intake device as claimed in claim 1, characterised in that the deflector (18) is formed by an extension of the leading end of the upper wall of said auxiliary intake pipe (16).

Inventors: SUGIYAMA, KEIICHI
Applicants: YAMAHA MOTOR CO., LTD.
Application year: 1981
Main classification: F02B31
IPC codes: F02M35, F02B31