US2630791A

US2630791A - Induction system for a two-cycle engine of three cylinders

Info

Publication number: US2630791A
Application number: US228065A
Authority: US
Inventors: Elmer C Kiekhaefer
Original assignee: Individual
Current assignee: Individual
Priority date: 1951-05-24
Filing date: 1951-05-24
Publication date: 1953-03-10
Anticipated expiration: 1970-03-10

Description

March 10, 1953 E. c. KLEKHAEF-ER 2,630,791

INDUCTION SYSTEM FOR A TWO-CYCLE ENGINE- OF THREE CYLINDERS Filed May 24, 1951 26 Ag I INVENTOR."

A [Zner fia r fllorneys Patented Mar. 10, 1953 INDUCTION SYSTEM FOR A TWO-CYCLE ENGINE OF THREE CYLINDERS ElmerC. Kiekhaefer, Ccdarburg. Wis. Application May 24, 1951, Serla'lNo. 228,065

This invention relates to engines having three cylinders firing consecutively and particularly Claims. (01. 123-.--'7:3)

to two-cycle engines employing crankcase induction and precompression for scavenging and recharging of the respective cylinders.

The invention provides two carburetors which are subject to individual adjustment and two separate induction systems associated therewith which supply jointly the intermediate crankcase with carbureted fuel and air and the respective adjacent crankcases individually with carbureted fuel and air.

The principal object of the invention is to supply equal amounts of carbureted fuel and air in equal proportions at all times to the three crankcases and cylinders.

A more particular object is to eliminate extensive manifold systems which cannot be arranged to deliver equal quantities of fuel at all speeds from one or more carburetors connected thereto.

A further object is to provide for the adjustment of the carburetion as required for efficient three-cylinder engine operation and maximum output.

A more particular object is to eliminate individual carburetor adjustment for each respective cylinder in an engine of three cylinders or more and to eliminate a corresponding number of adjustments.

A further object is to make the engine operation noticeably responsive to the adjustment of each carburetor employed without a common manifold system.

These and other .object s and advantages will be more fully set forth in the following description of a preferred embodiment of the invention as illustrated in the accompanyin drawing.

In the drawing:

Figure 1 is a side view of the engine with parts thereof broken away and sectioned generally in the vertical longitudinal plane of the cylinder axes; and,

Fig. 2 is across-section of the engine taken on line 2-2 of Figure 1.

The engine shown in the drawing includes the cylinder block I and the crankcase member 2, which latter is joined to one end of the block to enclose and support the crankshaft 3 in the upper and lower bearings 4 and 5, respectively.

Crankshaft 3 includes the three crank throws 6 spaced 120 about the crankshaft axis, and the bearings 1 intermediate the crank throws, which separate the crank throws axially of the crankshaft.

The semi-cylindrical bearing blocks 8 and 9.

assembled on bearings 1, engage and fit the corresponding complemental inner dimensions of member 2 and block I, to define therewith the three individual crank chambers H), H and i2 for the crank throws 6. The complementary blocks 8 separate the upper and intermediate chambers 10 and l l, respectively, and the similar blocks 9 separate the intermediate and lower chambers II and [2, respectively.

Each of the three cylinders l3 formed in block I is closed at its upper end by the block and opens downwardly into a corresponding crank chamber. A piston r4 carried in each cylinder l3 for reciprocation is connected by a rod l5 with the corresponding crank throw 6.

The intake ports l6 opening into one side of each cylinder [3 communicate with the corresponding crank chambers through the respective transfer passages H formed in block I. The exhaust ports l8 open from the opposite side of the cylinder into means, not shown, for discharge of the exhaust from the engine.

Ports l6 and i3 are controlled by movement of pistons I4 covering and uncovering the ports to open and close the same. During the upward stroke of the piston in each cylinder, the respective ports are closed, and the fuel charge in the upper combustion end of the cylinder is compressed. At the same time, the induction of the succeeding fuel charge into the crank chamber below the piston is effected, as will be described. After cylinder firing, the downward power stroke continues until the piston uncovers and opens ports IB, which provide for the exhaust of the burned gases, and shortly thereafter opens ports I6 for transfer of the compressed fuel charge from the crank chamber to the cylinder through a passage I],

The complementary upper and lower crankcase bearing blocks Band 9 are secured by screws is on the corresponding bearing! of crankshaft 3 and are provided respectively with

passages

20 and 2|.

Passages

20 and 2| register respectively with upper and

lower openings

22 and 23 in member 2, and open into the crank chambers through ports 24 formed in the blocks. Passages 20 open into chambers i0 and H, and passages Zl open into chambers ll and 12.

The reeds 25 seated on blocks 8 and 9 normally cover and close the corresponding ports 24 of each block. Each reed 25 is secured at one end to the corresponding block and is otherwise subject to flexing to open and close-the respective port in response to cyclic pressure changes effected within the chamber by movement of the respective piston.

The construction of blocks 8 and 9 and the reed valves formed by ports 24 and reeds 25 is similar to that described and claimed in the copending application of the present inventor for Crankcase Induction Valve for Two-Cycle Engine, Serial No. 117,325, filed September 23, 1949. I

Each

carburetor

28 and 21 includes a mixing passage 28 which is open at one end to receive the air.

The nozzles 29 of

carburetors

26 and 21 are connected to a suitable, constant fuel supply by the fuel conduit 33, shown only in part. Each

carburetor

26 and 27 includes a valve 3!, which provides for the adjustment of the fuel supply to the respective nozzle for a given operation condition of the engine and carburetor, and an adjustment lever or stem 32 which may be turned,

while the engine is operating, to regulate the corresponding valve and the mixture of carbureted fuel and air as desired and required for the most eihcient operation or greatest power output of the engine.

Carburetors

26 and 2? are carried by and secured to crankcase member 2 with the passages 28 in communication respectively with the upper and

lower openings

22 and 23 for the delivery of carbureted fuel and air mixture to chambers 19, H and i2.

Passages 20, communicating with the upper opening 22, provide for the delivery of the fuel mixture from carburetor 26 through ports 2 to chambers ill and H, in response to the upward induction stroke of the corresponding pistons l4, as described. Passages 2i, communicating with opening 23, provide for the delivery of the fuel mixture from carburetor 2! through ports 25 to chambers H and I2, similarly in response to the upward induction stroke of the corresponding pistons.

According to the invention, each carburetor 2E and 2'! is disposed for the delivery of fuel mixture to two of the three cylinders 43, so that engine operation may be controlled by an adjustment of each of

carburetors

26 and 21, first independently of and irrespective of the adjustment of the other, and thereafter reset as the adjustment required is indicated.

Optimum engine operation is approached by the adjustment of the two carburetors made first independently of the other and with the latter in each case deliberately set out of adjustment. With engine operation then dependent upon the first carburetor, the adjustment of the first carburetor may be made according to the response of the engine to such adjustment. When maximum output of the engine is reached, the indicated adjustment of the first carburetor is noted for later resetting, and the carburetor is then set out of adjustment. The adjustment of the other carburetor is then made as with the first carburetor, and thereafter both carburetors may be reset to the indicated adjustment required for the maximum output of the engine operating on both carburetors.

In engines provided with independent lubricating systems, not shown, each carburetor may be alternately adjusted with the other entirely closed to the delivery of fuel. In the engine shown and described which is adapted to be operated with the lubrication provided with and by the fuel, the adjustment of each carburetor is preferably made with the other carburetor providing the delivery of air with sumcient fuel for lubrication purposes with or without some combustion. If desired, such other carburetor may otherwise also be set to deliver an overrich mixture with a fuel-air ratio above the limits of optimum combustion, thus providing and adequately assuring the lubrication required.

The invention provides for the delivery of the fuel and air mixture to three cylinders or crankcases arranged in line in the precise amounts necessary for optimum engine operation.

In each instance, the engine is responsive directly to the carburetor being adjusted, and such adjustment may be made according to such response.

The elimination of extensive manifold systems extending beyond .a given cylinder or crankcase is provided by limiting the induction systems to the two'pair of adjacent cylinders. The coordinated adjustment of the carburetors is made possible by the separate induction systems which are independently adequate for engine operation. The adjustment of each respective carburetor independently of the other with the engine running allows their adjustment by observation of engine operation and response. After both carburetors have been separately adjusted, as described, they may be put in operation together for normal engine running with the full assurance that both carburetors are delivering the proper fuel charge to each of the three cylinders.

Various embodiments of the invention may be employed within the scope of the following claims.

I claim:

1. In an engine having three cylinders arranged in line and having consecutive induction cycles, two independently operable induction systems including separate, individual passages for delivery of carbureted fuel and air collectively to the intermediate cylinder and respectively to each of the other two thereof, and valve means controlling said passages and the induction of the fuel and air mixture including valve means associated with said intermediate cylinder separately controlling the passages of said independently operable induction systems.

2. In an engine having three cylinders arranged in line and having consecutive induction cycles, two separate carbureting means for the delivery of fuel and air mixture to the engine, said carbureting means being capable of individual adjustment, and two independent induction systems for delivery of the fuel and air mixture from the respective carbureting means collectively to the intermediate cylinder and respectively to the other two thereof wherein two of said three cylinders are subject and responsive to the adjustment of either of said carburetors.

3. In a two-cycle engine of the class described, a crankshaft having three crank throws spaced axially thereof and of each other about the rotational axis thereof, a cylinder block having three cylinders arranged in line and respectively in operative relation to the corresponding crank throws, a piston carried for reciprocation in each cylinder and connected to the corresponding crank throw, a crankcase supporting said crankshaft and including chambers separately enclosing each crank throw, each of said cylinders opening into the corresponding chamber below the respective piston and having intake ports above and controlled by the piston and in communication with said corresponding chamber, in.

dividual passages opening into adjacent crank chambers, separate carbureting devices for the delivery of carbureted fuel and air to the corresponding individual passages, valve means controlling said passages and the delivery or" carbureted fuel and air therefrom to the corr sponding crank chambers in timed relation to the reciprocation of said pistons, and valve means for individually adjusting said carbureting devices whereby the individual adjustment of the delivery of carbureted fuel and air to two crankcases and cylinders of the engine is provided by each of said valve means.

4. In a two-cycle engine of the class described, a crankshaft having three crank throws spaced axially thereof and 120 of each other about the rotational axis thereof, a cylinder block having three cylinders arranged in line and respectively in operative relation to the corresponding crank throws, a piston carried for reciprocation in each cylinder and connected tothe corresponding crank throw, a crankcase supporting said crank" shaft and including chambers separately enclosing each crank throw, each of said cylinders opening into the corresponding chamber below the respective piston and having intake ports above and controlled by the piston and in communication with said corresponding chamber, individual passages opening into adjacent crank chambers, separate carbureting devices for the delivery of carbureted fuel and air to the corresponding individual passages, and valve means controlling said passages and the delivery of carbureted. fuel and air therefrom to the corresponding crank chambers in timed relation to the reciprocation of said pistons and including means associated with the intermediate crank chamber and separately controlling said passages thereto.

5. In a two-cycle engine of the class described, a crankshaft having three crank throws spaced axially thereof and 1 0 of each other about the rotational axis thereof, a cylinder block having three cylinders arranged in line and respectively in operative relation to the corresponding crank throws, a piston carried for reciprocation in each cylinder and connected to the corresponding crank throw, a crankcase supporting said crankshaft and including chambers separately enclosing each crank throw, each of said cylinders opening into the corresponding chamber below the respective piston and having intake ports above and controlled by the piston and in communication with said corresponding chamber, individual passages opening into adjacent crank chambers, separate carbureting devices disposed to deliver carbureted fuel and air to the corresponding individual passages, valve means for adjusting said carbureting devices whereby the independent adjustment of the delivery of carbureted fuel and air to two crankcases and cylinders of the engine is provided by each of said valve means, and corresponding valve means controlling said individual passages and the delivery of carbureted fuel and air therefrom to the corresponding crank chambers in timed relation to the reciprocation of said pistons whereby tWo of the three cylinders of the engine are subject and responsive to the adjustment of one of said carbureting devices.

ELMER C. KIEKI-IAEFER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,050,456 Helin Jan. 14, 1913 1,318,542 Chevrolet Oct. 14, 1919 1,746,548 Meyer Feb. 11, 1930 2,254,365 Conover Dec. 2, 1941 2,282,458 Conover May 12, 1942