JPS59145348A - Thickening of gas mixture at start time of alternate ignition type two-cycle internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a starting mixture enrichment system for use in starting an alternating ignition two-stroke internal combustion engine.

Chokes have long been used to enrich the air-Q combustion mixture when starting an engine.

Additionally, some enrichment systems use manifold vacuum to cause the engine to draw fuel from the carburetor, but require the throttle to be closed.

The two-stroke internal combustion engine of the invention has at least two cylinders which are ignited alternately by the pressure in the crankcase when one crankcase is under negative pressure. Additional fuel flow passages also extend through each crankcase and are connected by a common flow passage. This common flow path connects to the float bowl of the vaporizer. A normally open control valve is disposed within this common flow path.

When attempting to start the engine, the control valve is vented and fuel is added into the common flow path. At the initial rotation of the crankshaft,
The pressure in one crankcase forces fuel into the other crankcase (which is under negative pressure). Further rotation of the crankshaft reverses the pressure and reverses the direction of fuel flow. As the engine continues to run, the control valves open alternately reverse the direction of fuel flow to accommodate alternate pressurized fuel injections into each crankcase.

This occurs regardless of the throttle settings.

The present invention will now be described with reference to the accompanying drawings.

The internal combustion engine 10 shown in the drawings is of a two-cycle alternate ignition type, and includes a cylinder block 11 . This cylinder block 11 comprises a pair of cylinders 12.13 each having a conventional reciprocating piston 14.15 arranged therein. The pistons 14, 15 move in the opposite direction and are connected to the crankshaft 16 in the usual manner in the case of the piston 14 in the crankcase 17 and in the case of the piston 15 in the crankcase 18. . Ordinary spark plug 1
9 is provided to ignite the engine 10.

The air/combustion mixture is provided by a carburetor 20 to the crankcase 17,18. The carburetor 2 DEG directs the air-combustion mixture through intake valve means (which in this embodiment includes a flanged reed block 21 of approximately 7-dimensional shape) in the usual manner. The reed block 21 has a chamber 22 provided between the carburetor throat 23 and each crankcase 17,18.
It is equipped with a conventional elastic boat-covered reed play (24.25) located inside the engine and providing alternating unidirectional passage of the air/combustion mixture to the engine. The air-fist combustion mixture ultimately flows through channels (not shown) to the distal side of each piston. This passageway is common and is illustrated in U.S. Patent No. 2,609,8
Please refer to issue 01.

The carburetor 20 may be of any suitable well-known type, and includes a seven-lunge base 27, an air force 28, and a throttle jr.
29, a float bowl 30, and a siphon 31. The carburetor 20 is attached to the engine 10 adjacent to the common chamber 22 by bolts 32 or the like. In this embodiment, the adapter/plate 33 is attached to the carburetor base 2.
7 and the engine 10, and the bolt 3
4. It is held in place by 4. Adapter plate 33
is an annular opening connecting chamber 22 and throat 23 +:+
It is equipped with 35.

It is desired to improve the startability of the engine lO by increasing the initial flow rate of fuel.

For this purpose, an additional fuel connection is provided between each crankcase 17, 18 and the carburetor 20. This connection is completely independent of the primary vaporizer output through the throat 23 and reed block 21.

As shown in FIGS. 2 and 4-6, additional connections to the crankcase 17 include a flow passage 36 in the float bowl 30 and carburetor body 26, and a hole 37 in the carburetor base plate 27. and into a short groove 38. The groove 38 coincides with the hole 39 in the adapter plate 33. Another hole 40 is provided in the flanged base of the reed block 21.
The hole 39 coincides with the hole 39 to allow fuel to pass through the crankcase 17.

With particular reference to FIG. 2.3, channel 36.41 merges into a common channel 46 provided in the body of float bowl 30. Channel 4
6 extends horizontally between the ends of the channel 36, 41 and then vertically upwardly to define a valve chamber 47 containing a spring-biased pole one-way valve. This valve chamber 47 is connected to a calibrated throttle channel 49, which is connected to the float bowl 30.
inside and usually ends below the fuel level. A control valve 48 is provided, which is manually operated by a push rod 50 extending externally of the carburetor 20.

In operation, control valve 48 is open to flow fuel through throttle passage 49 and valve chamber 47 to common passage 46, assuming normal levels of fuel in float bowl 30 during start-up. The additional flow path will be filled with fuel up to the liquid level in the float bowl 30. The crankshaft 16 is rotated to start the engine 10.

During the first revolution of the crankshaft, the piston takes in air.

During the compression stroke, positive pressure is generated in the crankcase 17,
A negative pressure is created within the crankcase 18 .

(Of course, this could also be reversed), which would then create a pressure imbalance between the connecting channels 36,41. As a result, the fuel therein is blown under pressure through the channel 41 and the above-mentioned connections into the crankcase 18 and joins the normal air-combustion mixture entering from the carburetor throat 23. Intake valve 21 is bypassed.

If the crankshaft 16 rotates another 180 degrees, this process is reversed. - That is, a negative pressure is created in the crankcase 17 and a positive pressure is created in the crankcase 18. The fuel (which has been replenished during this time in the channel 36.41) is blown out under pressure in the opposite direction and enters the crankcase 17 through the channel 36 and the connection mentioned above.

The process of alternately injecting additional amounts of fuel into the crankcase 17,18 continues as long as the control valve 48 is open, increasing startability and continuing fuel-rich warm-up as desired. As soon as the control valve 48 closes, the flow of fuel to the common flow path 46 and flow path 36.41 is stopped, so that the engine 1O continues to operate only with the normal air-combustion mixture from the carburetor 20. It turns out. During this time, air flows back and forth between the crankcases 17 and 18 through the flow passages 36 and 41, but it has been found that there is no adverse effect on the power and operating characteristics of the engine 10.

In the embodiment of the carburetor 20 shown in FIG. 2.3, the control valve 48
Several seconds may elapse from when the fuel is flat until enough fuel fills the flow path 3641 to achieve maximum enrichment. This delay time can be eliminated, if desired, with the embodiment shown in FIG. In this embodiment, the enrichment reservoir 51 is
9 and control valve 48, the flow passage 49 is provided in a bulkhead member 52 separating the main float bowl fuel chamber 53 from the sump 51.

In the embodiment of FIG. 7, additional fuel is supplied to crankcase 1.
7.184 While the fuel is being injected alternately, the fuel in the reservoir 51 continues to be replenished through the flow path 49. Even when valve 48 is closed, fuel continues to be supplied to reservoir 5, filling it to the fuel level in float bowl chamber 53. When the control valve 48 is opened to start the engine 10, fuel is immediately refilled from the reservoir 51 without flowing through the throttle channel.

The system described herein uses pressure in one crankcase to displace fuel and quickly transfers fuel to the other crankcase, resulting in faster engine starting. This device is independent of manifold vacuum and any throttle
It works with the settings.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a two-cylinder internal combustion engine to which the starting enrichment concept is applied. FIG. 2 is an enlarged front view of the engine partially cut away and partially shown. FIG. 3 is a vertical center cross-sectional view of the carburetor taken along line 3--3 of FIG. FIG. 4 is a vertical sectional view taken along line 4--4 in FIG. FIG. 5 is a partially broken vertical cross-sectional view taken along line 5--5 in FIG. FIG. 6 is a sectional view taken along line 6-6 in FIG. 5. FIG. 7 is a fragmentary diagram showing the use of a thickening layer.

Claims (11)

[Claims] (1), in internal combustion engines. (L) The first cylinder reciprocates in opposite directions within the first and second cylinders. (b) a cylinder block having a second piston; first and second crankcases combined with a second piston; (C) mounted on the internal combustion engine, the i11. means for alternately supplying an air-combustion mixture to the first and second crankcases during reciprocation of a second piston; (d) responsive to pressure in the alternate crankcases; combination with means for selectively supplying an additional amount of fuel to the crankcase alternately during the reciprocation of the piston during starting of the internal combustion engine; (2) In the combination set forth in claim 1, the additional amount supplying means includes an interconnected fuel receiving flow path connected to supply fuel to the first and second crankcases. , when the first and second pistons reciprocate, the direction of flow of fuel in the interconnected fuel receiving flow path is reversed to alternately inject pressurized fuel into the first and second crankcases. Did you do that? Characteristic combination. (3) In an internal combustion engine, (a) 1st. The first cylinder reciprocates in opposite directions within the second cylinder. a cylinder block having a second piston; (b) first and second crankcases that are combined with the first and second pistons; (c) a cylinder block that is attached to the internal combustion engine and that 1. means for alternately supplying an air-combustion mixture to said first and second crankcases during reciprocating movement of a second piston; (d) responsive to pressure in said crankcases; means for selectively supplying additional amounts of fuel to the crankcase alternately during reciprocation of the piston during startup of the crankcase. (e) the air/combustion mixture supply means includes a carburetor having a float pole, and (f) a common flow path in which the additional quantity supply means is adapted to receive fuel from the float pole of the carburetor. (g) said first and second flow path means and said common flow path forming an additional fuel connection; A combination characterized in that the flow direction of the fuel is reversed within the cylinder according to the reciprocating movement of the piston, so that the fuel is alternately pressurized and injected into the first and second crankcases. (4) In the combination described in claim 3. (a) the carburetor includes a throttle valve; and (b) reversal of the flow of fuel through the first and second flow path means is independent of the setting of the throttle valve. combination. (5) In the combination according to claim 3, (a) a throttle flow path connecting the float bowl to the common flow path; and (b) arranged in combination with the common flow path. selectively actuated one-way valve means for permitting fuel to flow from said throttle passageway to said first and second passageway means. (6) The combination according to claim 5, wherein the float bowl includes a housing that includes the throttle channel. (7) The combination according to claim 6, wherein the float bowl includes a fuel chamber to which the throttle flow path is connected. (8) In the combination described in claim 6. (a) said float chamber η) includes a bulkhead separating it into a secondary fuel chamber and a fuel enrichment reservoir; (b) said throttle passage is provided in said bulkhead, and said secondary fuel chamber and the fuel enrichment reservoir are connected. (9) The combination according to claim 8, wherein the common flow path communicates with the reservoir. (10), in internal combustion engines. (a) The first cylinder reciprocates in opposite directions within the first and second cylinders. a cylinder housing block having a second piston; (b) first and second crankcases combined with the first and second pistons; 1. means for supplying an air φ combustion mixture to said first and second crankcases alternately during reciprocation of a second piston; (d) responsive to pressure in said crankcases; (e) means for selectively supplying additional amounts of fuel to the crankcase alternately upon reciprocation of the piston during startup of the engine; (e) the air-combustion mixture supply means comprises a carburetor having a float; (f) first and second flow path means connected by a common flow path, the additional volume supply means being adapted to receive fuel from the float bowl of the carburetor; ) The first and second flow path means and the common flow path constitute an additional fuel connection, in which the flow direction of the fuel is reversed in accordance with the reciprocating movement of the piston. (h) the air-combustion mixture supply means further connects the carburetor to the first and second crankcases; intake valve means connected to alternately supply the air/combustion mixture to the crankcase; (+) the first and second flow path means bypassing the intake valve means; combination. (11) In the combination according to claim 10, (a) the carburetor is attached to a base member attached to the internal combustion engine, and (b) the carburetor is trapped between the base member and the internal combustion engine. (c) the first channel extends through a short groove in the base member to a first opening in the plate;
and (d) the second flow path communicates through an elongated arc-shaped groove in the base member to a second opening in the plate that is substantially diametrically opposed to the first forward opening. ing