JPS58167822A - Supercharge device of 4-cycle engine - Google Patents

Abstract

PURPOSE:To both simplify construction of a device and reduce its cost and a level of noise, by using a crank chamber of an engine main unit as the supercharge working chamber to eliminate the necessity for separately providing a supercharger. CONSTITUTION:In a partial load operative range of an engine, a relief valve 23 is fully opened, and a mixture flowing from an introducing passage 21 to a crank chamber 7 reversely flows from the valve 23 to the passage 21 at pressurization of the chamber 7 not to perform supercharge action. In a high load operative range of the engine, the valve 23 is fully closed. In a lifting stroke (compression or exhaust stroke) of a piston 3, a mixture introduced into the chamber 7 through an introducing valve 22 from the passage 21 is pressurized as the piston lowers. If compressive pressure exceeds opening pressure of a piston valve 15, the valve 15 tends to lift a swivel arm 33. When a push rod 29A becomes liftable by a cam mechanism, the arm 33 turns a supercharge valve 17A to open a supercharge port 16A and close an intake port 11 in the upstream side.

Description

[Detailed description of the invention] The present invention relates to a supercharging device for a four-stroke engine.

In order to increase the maximum output of the engine without changing the cylinder capacity,
A supercharging device is sometimes provided to improve intake air filling efficiency, but supercharging devices are generally classified into target chargers and mechanical superchargers.

The main charger uses the energy of the exhaust gas to drive the exhaust turbine and the intake consolerator for supercharging. supercharge the intake air through the

However, these are all equipped with a supercharging device separate from the engine main body, so it is difficult to drive. These problems include energy loss (if the charger is a charger, loss due to increased exhaust pressure), increased weight and cost, and increased noise.

In order to solve these problems, the present invention utilizes the crank chamber of the engine body as an operating chamber for supercharging.
The purpose of the present invention is to provide a supercharging device for a four-stroke engine that has little energy loss, low noise, and low cost.

Embodiments of the present invention will be described below based on the drawings.

Figures 1 and 2 show the present invention applied to a two-cylinder, four-stroke engine.As will be described later, the present invention is based on the premise of an even-numbered Kiso engine in which the piston phase is the same in at least two cylinders. do.

First, in the figure, 1 is a cylinder head, 2 is a cylinder block, 3 is a piston, 4 is an intake valve, 18 is an exhaust valve, and 10 is a combustion chamber.

The piston 3 is connected to a crankshaft 6 via a connecting rod 5, and the crank chamber 7 on the lower surface of the piston 3 is filled with an oil valve 8.
cover 9 on the lower surface of the crankshaft 6
partitioned to form an independent space, which constitutes a working chamber for supercharging.

When the engine cycle rotates, one cylinder #1 and #2 cylinder is in the intake stroke and the other is in the expansion stroke.

Furthermore, regarding piston 3, this means that they are in the same phase, and the three lines of the circular piston rise at the same time.
Repeat the descent.

The cylinder head 1 has an intake port 11 and an exhaust bow) 12
An intake bow 11 is connected to an intake passage (AFI manifold) 14, and an air-fuel mixture is supplied from a carburetor (not shown).

Both cylinders φ1. 2 intake chamber) 11 and the above 2 ink chamber 7
A supercharging passage 13 is formed in the middle of this supercharging passage 13 to communicate with the
! <Piston valve 15 is interposed.

The supercharging passage 13 is connected from the downstream side of the piston valve 15 to both intake ports 11 and branches into supercharging ports 16 and 16B.

Supercharging valves 17A and 17B are provided at the connection portions where these supercharging boats 16A and 16B communicate with each intake boat 11, respectively. The cam mechanisms 20A and 20
Linked with B.

On the other hand, a fresh air introduction passage 21 branched from the intake passage 14 is connected to the crank chamber 7, and this connection part has an introduction valve 22 constituted by a check valve (reed valve) and an accelerator pedal (not shown). A relief valve 23 that normally opens in conjunction with the accelerator and closes only when the accelerator is fully open is connected to a branch path 21A in parallel.
21B. As shown in FIG. 5, the relief valve 23 is connected to the accelerator wire 24, and is urged toward the return side (opening side) by the return swell ring 36.

The inlet valve 22 opens when the crank chamber (working chamber) 7 expands as the piston 3 rises and the pressure decreases, allowing fresh air to be sucked into the crank chamber 7.

In the cam mechanisms 20A and 20B (as shown in FIGS. 3 and 4), cam reds 27A and 27B abut on dedicated cams 26A and 26B, respectively, which are attached to cam shaft muscles for driving intake and exhaust valves. At the other end of this is a bushel rod 29 via a crank lever 28.

29B are connected, and this bushing rod 29A, 29B
The other ends abut the rotating tips of levers 31A and 31B, which are fixed by 3°K to the valve shafts of supercharging valves 17A and 17B, respectively.

L””-31A and 81B are springs respectively! This forces the supercharging valves 17A and 17B to close.

Both ends of a swing arm 330 are in contact with the lower sides of the levers 31A and 31B, and the center portion of the swing arm 33 is connected to the piston valve 15 described above via the slide rod 34 and a pin 33A.

Gutsushirotsudo 29A or 29B is cam position 27A.
, 27B are in contact with the valleys of the cams 26A, 26B, upward movement is possible, and at this time the piston valve 15 rises and the swinging arm 33 moves toward the bin 33A.
When the tilt lever 31K or 31B is pushed up with , the supercharging valves 17A and 17B open.

When the supercharging valves 17 and 17B are opened, they close the upstream side of the intake port 11, as shown by the dashed line in FIG.

Next, the operation will be described. The effective volume of the crank chamber 7 formed on the lower surface of the piston 3 changes as the piston 3 moves up and down.

#1. Since the piston 3 of the #2 cylinder moves up and down in the same phase, the volume change at this time is the sum of the area of the two cylinders multiplied by the piston stroke.

Incidentally, in engine partial load operation, that is, in an operating range where a large amount of intake air is not required, there is no need for supercharging, but in such a front state, the relief valve 23 is fully opened by the action of the return spring.

When the volume of the crank chamber 7 changes with the movement of the piston, that is, when it expands due to the rise of the piston 3, the air-fuel mixture flows from the introduction passage 21 through the introduction valve 22 and this relief valve 23, and the air-fuel mixture flows into the piston 3. It is discharged when the cylinder contracts due to descent, but since the relief valve 23 is fully open, the air-fuel mixture in the crank chamber 7 flows back into the introduction passage 21 and does not push up the male stone valve 15. .

In this state, the supercharging valves 17A, 17B are activated mainly in the latter half of the cam machine suction stroke, and the bushing rod 29A is activated.

Since the piston valve 15 does not push up the swinging arm 33 even if 29B is in a state where it can be raised, the supercharging port 16A
, 16B are not opened, and therefore, the air-fuel mixture is mostly taken into the combustion chamber 10 by the intake air/-) 115- as the intake valve 4 is opened.

In other words, no supercharging is performed in the partial load range.

On the other hand, in the high load range near full throttle, the relief valve 23 is fully closed, so the process of the piston 3 rising (
1 inlet valve (check valve) in crank chamber 7 during compression and exhaust stroke
The air-fuel mixture sucked in from the introduction passage 21 via 22 is
As the piston 3 descends, it is pressurized.

When the compression pressure exceeds the closing pressure of the piston valve 15,
The piston valve 15 is pressed and tries to push up the swing arm 33.

Therefore, at this time, for example, if cylinder #1 enters the intake stroke, when the cam mechanism 20m allows the cylinder rod 29A to rise, the swinging arm 33 tilts while rising around the bin 33A. The supercharging valve 17A opens the supercharging/-) 16A via the /4-31A, and at the same time, the upstream intake air? - Close port 11.

Therefore, the pressurized air-fuel mixture flows from the supercharging passage 13 to the intake port 11 via the supercharging &-) 16A, and is further fed into the combustion chamber 10 as the piston 3 descends.

In this way, when the engine is under high load, a sufficient amount of air-fuel mixture is forced into the cylinder due to the supercharging effect, increasing the engine's maximum output.

When the suction stroke ends, the supercharging valve 17A is closed via the bushing rod 29A of the cam mechanism 20A, and at the same time, the male stone valve 15 closes the supercharging passage 13, and the supercharging action ends.

Then, in the process of the piston 3 rising again, the air-fuel mixture from the fresh air introduction passage 21 is sucked into the crank chamber 7 via the introduction valve 22, and during the intake stroke on the cylinder #2 side of the A supercharging effect similar to that occurs.

Next, FIG. 6 shows a simplified version of the cam mechanisms 20A and 20B, in which the spring 40 is installed so that the supercharging valve 17A biases the lever 31A in the normal pressure closing direction, the bushing rod 29A, the cam rod 27A, the cam 26A, etc. etc. are removed.

In other words, regardless of the rotation angle of the lever 31A, the spring 40 is set so as not to exceed the axis of the lever 31A. If the force becomes stronger than the force acting on the spring 40, both the supercharging valves 17A and 17B will open, but since the intake valve 4 of one intake port 11 is closed, the air-fuel mixture will not flow into the cylinder on the intake stroke. However, part of the air-fuel mixture is fed under pressure to the cylinder on the expansion stroke side.
) Since it also goes into 11 (dead becomes a knee)
, the supercharging efficiency will decrease slightly.

Figure 7 shows piston valves 15A and 15B at both supercharging ports) 1
6A and 16BK are installed respectively, and the slide rod 3
4'A and 34B are the respective levers 31A and 31
K is designed to directly push up the lower surface of the rotating tip of B.

In this case, the piston valve 15A (15B) on the suction stroke side
Only the piston valve 15B (1
5A) and supercharging valve 17B (17A)/-
) 16B (16A) has no air-fuel mixture flowing into it,
Therefore, there is an effect of reducing dead neem and improving supercharging efficiency.

In FIG. 8, the piston valve 15 is omitted and the cam 45 directly drives the supercharging valve 17A (17B).

The fulcrum 41 of the crankshaft 28 connected to the cam rod 27A driven by the cam 45 is connected to the lifting block 4.
2, and connect this lifting block 42 to the accelerator wire 4.
0. When the block 42 is in contact with the peak of the cam 44 (the state shown in the figure), the movement of the cam rod □゛''''27 remains unchanged. The transmission is transmitted to Bushrod 29 via the crank lever 28, but when the cam 44 comes off the peak, the block 42 drops, so even if the cam rod 27A strokes, the crank Leno F-28 does not move. , Therefore, the supercharging valve 17A will not open.

The cam 44 is set so that the block 42 rides on the peak when the accelerator is fully opened.

Therefore, the supercharging valve 1 is used only during high loads when supercharging is required.
7A (17B) can be opened during the suction stroke, and is kept closed during other partial loads.

In addition, at partial load, the relief valve 23 is open and the supercharging pressure does not increase, so the supercharging valve 17 people.

Although supercharging is not performed even if 17B is opened, it is preferable to keep the valve closed from the viewpoint of the flow of the air-fuel mixture and durability.

(However, depending on the case, the fulcrum 41 of Cranfret/mother 28 may be fixed so that supercharging valves 17A and 1
7B can be operated and left in the same position.Next, FIGS. 9 and 1C show the supercharging valve 17 and 17B changed from a butterfly lid to a rotary type, and the rotating shaft 50 is replaced by a crankshaft (not shown). 1 of the rank axis rotation by interlocking with
Rotate at the ratio of

Rotary pulps 51A and 518 are arranged at the outlet portions of supercharging ports 16A and 16B.

The rotary pulps 51A, 51B are relative to the rotating shaft 50,
The valve plate 52 is installed with a phase of 180° in rotation angle.
When the notch 53 matches the supercharging port 16A (16B), supercharging air is forced into the combustion chamber 10 from the intake port 11.

Of course, the positional relationship is set in advance so that the notch 53 coincides with the supercharger 1-) when the intake valve opens.

When the Ta-tariparts 51A and 51B are provided in this way,
Pulp opening/closing noise is reduced and operation followability at high rotation speeds becomes smoother. In addition, the notched groove 5 along the valve plate 52
4 is formed so that the intake port 11 is opened throughout the entire intake stroke, and therefore, during partial load when supercharged air-fuel mixture is not supplied, the intake port 11 is opened through the notch groove 54 of the intake port 11.
The air-fuel mixture is drawn into the combustion chamber 10.

FIG. 11 is a schematic diagram of an embodiment in which the present invention is applied to a four-cylinder engine.

For cylinders #1 to #4, the firing order is ($ 1-#-3-
$4-〇2), therefore #1 cylinder and #4 cylinder
The pistons 3 of the cylinders are in the same phase, and the pistons 3 of the #2 and #3 cylinders are also in the same phase.

Then, the piston 3 is in the same phase as the crank chambers 7A and 7.
D, 7B and 7C are in communication with each other (each is partitioned off from the others), and the respective supercharging passages 13A and 13D, and 13B and 130 are in communication with each other.

In addition, the piston valves 15 and 1 of the supercharging passages 13A and 13D
5D are independent, but the supercharging passage 13B and the piston valve 15B of 130 are shared.

In this way, the crank chambers of #1 and #4 cylinders (
The working chambers) 7A and 7D expand and contract synchronously, and the crank chambers 7B and 7C of the #2 and #3 cylinders also expand and contract at the same time, so the air-fuel mixture is pressurized and sent to each intake air 1-) 11. In each of the above embodiments, if oil is stored in the crank chamber 7, this will be sent to the combustion chamber along with the supercharging air, increasing oil consumption.
It is desirable to configure a so-called dry sump type lubrication system.

A forced lubrication system is used to reliably supply lubricating oil to each sliding part, and a lubricating pipe is also formed at the small end of the connecting rod to feed lubricating oil to the sliding surface of the cylinder.

In addition, the fresh air introduction passage 21 may be configured to take in only air from upstream of the carburetor, and in this case, the air-fuel mixture generated in the carburetor is set to become rich during supercharging, and Make sure that a predetermined air-fuel ratio (near the stoichiometric air-fuel ratio) is obtained in total.

In addition, if a fuel injection valve is provided in place of the carburetor, providing the fuel injection valve in the intake air downstream of the supercharging valves 17A and 17B and in the jet 11 will prevent the fuel from flowing into the crank chamber 7. Therefore, fuel supply response etc. are significantly improved.

In addition, in this case, the fresh air introduction passage 21 is arranged to perform supercharging by utilizing the crank chamber according to the present invention, as shown in FIG. This significantly simplifies the structure and reduces weight, cost, and noise compared to conventional systems that require a separate supercharger.In addition, during partial loads when no supercharging is performed, the crank chamber is released. Therefore, there is less compression work loss and efficient supercharging with less energy loss.

When applied to a two-cylinder engine, the fuel supply device (carburetor)
It is possible to reduce intake pulsation through the air and suppress variations in air-fuel ratio.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of the first embodiment of the present invention, FIG. 2 is a sectional view taken along line A-A, and FIG. 3 is a sectional view of the vicinity of the supercharger.
FIG. 4 is a sectional view taken along the line B-B, and FIG. 5 is a sectional view of the vicinity of the relief valve. 6 to 8 are sectional views showing other examples of the opening/closing mechanism for driving the supercharging valve, FIG. 9 is a sectional view showing other examples of the supercharging valve, and FIG. 10 is a C-C thereof. A line sectional view and FIG. 11 are schematic configuration diagrams of an embodiment in which the present invention is applied to a four-cylinder engine. 1... Cylinder head, 2... Cylinder block,
3... Piston, 4... Intake valve, 5... Connecting rod, 7... Crank chamber (working chamber), 8... Oil drain, 9... Cover, 10... Combustion chamber , 11...
Intake 1-), 13... Supercharging passage, 14... Intake passage, 15... Piston valve, 16A, 16B... Supercharging 4
-G, 17A, 17B...Supercharging valve, 20A, 20B...
...Cam mechanism, 21... Fresh air introduction passage, 22... Introduction valve, 23... Relief valve, 25... Camshaft, 26A
, 26B...cam, 29A, 29B...gutsushirotsudo, 33...swinging arm. Patent applicant Nippon Motor Co., Ltd. Figure 1-A @ Figure 6 Figure 7 Figure 9

Claims (1)

[Claims] 1. In an even multi-cylinder four-stroke engine in which the pistons between two cylinders are in the same phase, the crank chambers between the cylinders whose pistons are in the same phase are communicated with each other, and this crank chamber and the intake port of the cylinder are connected. A supercharging passage is formed connecting the two, and a supercharging valve that opens during the suction stroke is interposed in this supercharging passage, while a fresh air introduction passage is connected to the crank chamber, and an introduction valve that opens when the piston rises is provided in this introduction passage. A supercharging device for a four-stroke engine characterized by: 2. The supercharging device for a four-cycle engine as set forth in claim 1, wherein the fresh air introduction passage is provided with a relief valve that closes the introduction valve when the engine is under high load. 3. The supercharging valve is configured to open and close in conjunction with a screw valve that opens the supercharging passage when the pressure in the crank chamber rises above a predetermined value. A supercharging device for a four-cycle engine as described in Section 1.