MOVABLE JET CARBURETOR

Abstract: A movable jet of fuel emitted under low pressure from a group of small holes distributed over an area is linked to the throttle plate (7) of a carburetor such that the excessive amount of fuel at partial load falls into a drainage area and flows into a pool (6) from which it returns to the fuel tank through an overflow line. The pool (6) has a fixed fuel level to serve an idling system. An engine-driven fuel pump delivers for each intake stroke of the engine a fixed amount of fuel to the movable jet and a bypass device (9) which has a variable opening to bypass a part of fuel to the drainage area according to the speed of the engine.

Description: MOVABLE JST CARBURETO - - TECHNICAL FIELD This invention relates to the movable jet carburetor of a. spark, ignition internal combustion engine. BACKGROUND ART By accident during ray experiment on a new method of fuel infection system with Bosch gasoline injector,. I found that the engine speed can be varied by allowing a portion of the fuel jet to enter the engine manifold. I also, found that the amount of fuel emitted from the injector for each intake stroke of the engine had to be reduced when the engine speed was increased » and vice versa, for a fixed relative position between the injector and the throttle plate of the carburetor. Brief DESCRIPTION OF DRAWINGS An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is the elevation of a movable jet carburetor with, a jet element of straight tube type. The partial views or sections are shown as Figures 1A, IB, 1C, ID and IE. Figure 2 is the detail of one kind of fuel pump which is needed to supply fuel to the carburetor. Figure is the detail of one kind of mechanical linkage for transmitting the motion of the throttle plate to the jet element shown in Figure 1. Figure 3A is the top view of Figure 3- Figure 3B is the side view of the joint of the linkage at the jet element. Figure i is the detail of one kind of mechanical linkage for transmitting the motion of the throttle plate to a jet element of polygon type. Figure l+λ is the top view of Figure . Figure 5 is the flow diagram of fuel system. EMBODIMENTS OF THE INVENTION Figure 1 is. the full, scale drawing, of a typical carburetor of this, invention. Casing 1 has an air duct of 50 mm. inside diameter, is connected to the air filter 3 of the engine, has o& e throttle plate S of conventional type in the air duct* has one air vent 1 located above the choke plate, to keep the air pressure atmospheric inside the adjacent dust-proof box comprising drainage tray 2 and lid 3, and has a fuel pool 6 of 20 mm- in depth which is maintained by the overflow return 2 as shown in Figures ID and A* to the fuel tank of the engine as shown in. Figure 5- Figure 3 shows the mechanical linkage which lin s, the throttle plate Λ and fuel jet element 13 at the position of mini- ttun fuel injection. Holes 14 for emitting fuel are at this moment a l outside the air duct and above the area of tray 2 (Fig. 1) sϊich. that the whole amount of fuel is drained tα the pool where a g-nal.1 amount is siphoned through th.e drilled passage (.Tigs. IE and ID) and miyea with, the idling air entering through- orifice 27 to form a mixture which enters the aju? duct 27 through the opening of variable orifice Λ with control needle 1Ω2 and emits as an idle jet when the throttle plate is closed. When the throttle plate is slightly open, additional mixture enters the air duct through the small inclined holes located at the level of the throttle plate to augment the idle jet. The drilled passage comprises 3 π.m drilled holes of which the ends are plugged with, ping 202. As shown in Figure 1, the Jet element 1 has a fuel inlet. nipple 28 at the middle. 13 is made of a tube of 6 * 5 π_m outside diameter. During assembly, the right side of 13 enters the left side beveled hole of the air duct and run-t. through the bearings 15 an the right side. Then tray 2 with, rubber bushing 44 already in place is mounted with screws 203 (Fig. ID) onto the pool side of casing 1. It is understood that such minor details as gaskets,- washers, springs for control needles, retainers for pins or swivels, etc., are not shown on the drawings. Flexible tube 11 of enough length is used to join 28 and fuel outlet 4 of bypass device 9 which is fastened to lid 3 with screws 203 (Fig. 1A). Lid 3 is fastened to tray 2 with screws, and its seam joining 1 is sealed with rubber seal 26 for dust-proof. The sides of 1, 2 and 3 form an enclosed box which has an air vent 41 leading to air filter 43. When the jet element moves from right to left, and vice versa, its protruding part outside the enclosed space may get dust which is wiped off by sponge kZ enclosed in retainers 29 and 30 as shown in Figures IB and 1C respectively. As shown in Figures 1 and 1A, the bypass device 9 has fuel inlet 10 connected with tube to the outlet 33 (Fig. 2) of the fuel pump. The main part of fuel flows through outlet i to supply jet element 13, while the remaining part is flowing through bypass 12 controlled by needle 101 (of which the opening is variable by manual action or by an nshown diaphragm sensing the engine intake manifold vacuum, or by an unshown electronic device) and entering inlet 5 of li 3 and then falling onto tray 2 and finally entering pool 6 by gravity- As shown in Figure 3 > rotary crank 17 is made of 2,3 mm thick, steel plate which has a punched hole of the shape of two parallel sides and two circular arcs to fit into the end of the axle of throttle plate for rotating together,. Figure 3A shows the developed top view of crank 17 which is retained in place with collar 301 and cotter 302 and which has a bent-over tip at the lower end to accommodate screw 201 for adjusting the stroke of jet element 13 by changing the clearances between the cranks and stop blocks 21 and 22 for minimum and maximum fuel injection from jet element respectively,. The upper end of each crank joins one connecting bar 20 throug swivel 303 * The other end of each connecting bar swivels on one end of rod IS., Qrαsshead clamp 19 grasps the middle of 18 and one end of jet element 13, and allow 13 tα be set at an adjustable position relative to casing. 1. As an alternative design shown in Figure i+, jet element 13 is of the shape of a square wheel rotating, about a vertical axle which is parallel to the air duct of casing 1 and constrained by bearings 15 affixed to 1- Fuel enters 13 through inlet 16 and flows through drilled passage plugged with plugs 202 at the ends. The jet element protrudes into air duct through a slot with beveled edges to divide the fuel jet into two parts, one joining the air stream to form a mixture and the other falling into the drainage area of tray 2 (Fig. 1). The axles of 13 and throttle plate 7 are perpendicular to each other in the side view of Figure . The axles are not coplanar. The cranks 17 and 23 attached to them are joined by connecting bar 20 at both ends with Hooke's universal joint * The cranks and the connecting bar are made of punched and stamped steel plates. Figure 2 shows the fuel pump which is of the same type as that for supplying fuel to the float chamber of a conventional induction type carburetor. However, it should be driven by a - k - different cam which delivers one or more strokes to rocking lever 37, and spring 36 of diaphragm 3k should be strong enough for giving the diaphragm enough length of upward stroke to deliver enough amount of fuel per intake stroke of the engine when the engine speed is the highest and the time interval between the separation and reunion of 37 and pulling rod 35 is the shortest. The slot in the lower part of 35 and the stroke of 37 should be long enough for allowing the diaphragm to deliver enough amount of fuel per intake stroke of the engine when the engine speed is the lowest and the load or external torque on the engine crank shaft is the highest► Spring 39 should be strong enough for keeping 37 always in contact with the cam of the engine while 37 is rocking around 38, The space between the diaphragm and pump housing 31 has air vent i_0. Inlet 32 and outlet 33 are of non-return type, and connected to the fuel tank of the engine and the inlet 10 of bypass 9 (Fig»l) respectively. 38 is a fixed fulcrum * The fuel pump can also be of the same type as that of a diesel engine * However, its stroke can be fixed and its outlet pressure would be below 2 bar. Figure 5 is the flow diagram with arrowheads showing the direction of fuel flow.

Claims: CLAIMS 1. A method of providing air-fuel mixture of required air-fuel ratio to the carburetor of a spark ignition internal combustion engine by providing the carburetor with: (1) a casing which has: one air inlet to admit ambient air,. one mixture outlet to deliver said air-fuel mixture to the engine, and one air duct joining said air inlet and mixture outlet; one enclosed box attached to the air duct which has: one main fuel inlet to admit main fuel supply, one bypass fuel inlet to admit bypass fuel, and one fuel drainage area located outside and adjacent to the air duct, oft..- fuel pool located below said drainage area and having an overflow return to the fuel tank of the engine such that the pool has a fixed fuel level, equivalent to that of the float chamber of a conventional induction type carburetor; bearings for one choke plate and one throttle plate which are located in the air duct; and bearings and openings for the movable fuel jet system describ¬ ed below; (2) a fuel supply bypass device which has a variable opening to bypass a part of fuel to said drainage area according to the speed of the engine; (3) a movable fuel jet system which has: one fuel jet element of which a part stays inside said air duct and the remaining part stays above said drainage area,, and which has a group of small holes distributed over a part of its surface area for emitting fuel, and which can move within the constraint of bearings affixed to said casing, one fuel jet element connected to the main fuel inlet of said casing with flexible tube to allow motion, and one linkage to transmit the motion of said throttle plate to the fuel jet element such that for each small step movement of the throttle plate there is a relative small step movement of the fuel jet element to change the number of small holes for jet over the areas inside and outside the air duct such that the ratio of air- uel mixture to enter the engine is fixed for a fixed engine speed, throttle position,, and rate of fuel supply; and ( k) one fuel supply system which delivers a fixed amount of fuel from the fuel tank of the engine to said, fuel supply bypass device and then to said fuel jet element for each intake stroke of the engine. 2« In connection with claim 1, said fuel supply system delivers a variable amount of fuel which varies with the engine speed and said bypasβ devic is set to bypass a fixed volumetric ratio of fuel from the total amount supplied by the fuel supply system regardless of engine speed * 3. In connection with claims 1 and 2, said engine speed for controlling said fuel supply system and said bypass device is sensed by the intake manifold vacuum of the engine.

Inventors: TING HUI-TZENG, TING, HUI-TZENG
Applicants: TING HUI TZENG, TING, HUI-TZENG
Application year: 1985
Main classification: F02M7
IPC codes: F02M7, F02M17, F02M71