JPS6088810A - Internal-combustion engine - Google Patents

Abstract

PURPOSE:To make two-stroke cycling performable with the specified load or more, by installing suction and exhaust valves to perform four-stroke cycling on one side and suction and exhaust valves on the other to perform two-stroke cycling to one cylinder, respectively. CONSTITUTION:A suction valve 13 and an exhaust valve 15 for four-cycle use are all installed in a combustion chamber 5, while an exhaust valve 28 for two- cycle use is installed in a cylinder 4. A supercharger is installed in a suction passage which interconnects the two-cycle suction valve. In addition, with a load detecting device 55 for an engine, a hydraulic selector valve 49 is selected whereby oil pressure to a hydraulic cylinder 31 is controlled. With this constitution, when the engine is highe in its load than the specified one, two-stroke cycling takes place while four-stroke cycling takes place when the engine is lower in its load than the specified one.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion engine equipped with a supercharger such as an exhaust turbocharger.

In general, in internal combustion engines, increasing the compression ratio is effective in increasing output and reducing fuel consumption. on the other hand,
Modern internal combustion engines are equipped with superchargers such as exhaust turbo superchargers to improve output and improve fuel efficiency.However, supercharging an engine increases the effective compression ratio of the engine. To prevent knocking from occurring easily, the compression ratio in conventional supercharged internal combustion engines is set in advance to a low value by the amount that the effective compression ratio increases due to supercharging.

However, a supercharger such as an exhaust turbo supercharger starts operating when the engine load exceeds a certain value, and in the load range below that, the effect of supercharging is almost negligible (in fact, the effect of supercharging is Although the supercharger creates suction resistance to the air and reduces charging efficiency, the compression ratio is as low as described above, so the engine output and fuel efficiency at that time are lower than in the case of a non-supercharged engine. It was going to get worse.

Therefore, Japanese Patent Application Laid-Open No. 55-37550 as a prior art proposes an exhaust turbocharged internal combustion engine, in which the intake boat to the combustion chamber is divided into two (first and second), and the supercharging While the supercharging from the machine is supplied to the first intake port, in the low load range atmospheric air is sucked in from the second intake boat by the suction action as the piston descends. However, even in this case, the compression ratio must be set to a low value in advance by the amount that the effective compression ratio increases due to supercharging, so It was not possible to sufficiently improve output and reduce fuel consumption in low load ranges while maintaining high output and low fuel consumption in high load ranges due to the low compression ratio in the low load range. .

In the low load range where the engine load is below a certain value, the supercharger has almost no effect. Therefore, the present invention enables a high compression ratio as a non-supercharged 4-cycle engine that does not perform supercharging. In the load range above this, by using a two-cycle engine and performing supercharging, the output in the low load range can be increased while maintaining high output and low fuel consumption in the high load range. This makes it possible to achieve sufficient improvement and reduction in fuel consumption.

The present invention will be described below with reference to drawings of embodiments. In the drawings, 1 is a cylinder block, 2 is a cylinder head, 3 is a piston that reciprocates within a cylinder 4 in the cylinder block 1, and 5 is a concave portion on the lower surface of the cylinder head 2. The cylinder throat 2 is provided with an intake boat 6 and an exhaust port 7 for 4-cycle use.
In addition, a 2-cycle intake boat 8 is provided,
An ignition plug 9 is provided, and a camshaft 10 is provided on the upper surface of the cylinder nozzle 2, which rotates once per two revolutions of a crankshaft (not shown).・Bottom dead center of N3 (B.

A two-cycle exhaust port 11 is provided at a position appropriately above the top surface in D and C) so as to open into the cylinder 4.

An intake valve 13 with a spring 12 and an exhaust valve 15 with a spring 14 are provided at the openings of the intake boat 6 and the exhaust port 7 to the combustion chamber for the 4-cycle, respectively.
The exhaust valve 15 is interlocked with the single cam 20.21 on the camshaft 10 via a rocker l5ii18.19 pivoted on a hollow rocker shaft 16.17, and is connected to the intake valve and It is configured to open and close with the same timing as the exhaust valve, and the intake boat 6 is connected to an intake passage 23 from the air cleaner 22, and the exhaust port 7 is connected to an exhaust pipe 24 to the atmosphere. .

An intake valve 26 with a spring 25 is provided at the opening of the two-cycle intake boat 8 to the combustion chamber 5, and an exhaust valve 28 with a spring 27 is provided at the opening of the exhaust port 11 to the cylinder 4. The intake valve 26 is connected to the double cam 30 on the camshaft 10 via a swing M29 pivotally supported on the rocker shaft 16.
In conjunction with this, the piston 3 is configured to open in a section from the bottom dead center (B, D, C) until it rises approximately 90 degrees at the crank angle. The intake boat 8 is configured to come into contact with a cam 33 on a rotating shaft 32 and open when hydraulic pressure is supplied to the hydraulic cylinder 31. A supercharging passage 36 from the exhaust port 11 is connected thereto, and the exhaust turbine 34 is inserted into the exhaust passage 37 from the exhaust port 11 .

Further, the intake passage 23 and the supercharging passage 36 are each provided with fuel supply means 38, 39 such as a carburetor or a fuel supply nozzle.

Between the tip of each swinging arm 18, 19, 29 and each intake valve 13, 26 and exhaust valve 15, each of these valves can be set in an operating state or a non-operating state depending on the load of the engine. A switching means 40 is provided for switching between the two. As shown in FIG. 4, this switching means 40 includes a plunger 42 that is slidably inserted into a hydraulic chamber 41 formed in the tip of each swing arm toward each valve, and the lower end of this plunger 42 is inserted into a hydraulic chamber 41 formed in the tip of each swing arm. The upper end of each valve is pressed into contact with a spring 43 in a hydraulic chamber 41, and each swinging arm is provided with an oil passage 44 that communicates with the oil pressure chamber 41. A valve body 48 is slidably inserted into the switching chamber 45 to open and close a communication path 47 from the hydraulic chamber 41 to the atmosphere, and hydraulic pressure is supplied to the oil path 44. This hydraulic pressure causes the valve body 48 to communicate the oil passage 44 with the hydraulic chamber 41 via the check valve 46 and at the same time throttle the communication passage 47 to the atmosphere, so that the plunger 42 protrudes under the hydraulic pressure. When the joint valve is opened and closed by the swinging of each swinging arm, and the hydraulic pressure to the oil passage 44 is discharged or becomes low pressure, the valve body 48 moves into the oil passage 44 as shown in FIG.
4 and the hydraulic chamber 41, and at the same time fully open the communication path 47 to the atmosphere, thereby releasing the hydraulic pressure in the hydraulic chamber 41. The structure is such that the joint venture is completely inactive so that it does not open or close.

In addition, 49 is a 2-port 2-position hydraulic switching valve.
One hydraulic passage 50 in the hydraulic switching valve 49 is connected to the four hydraulic passages 50 through a passage 51.52 in the rocker shaft 16.17.
The oil passage 44 of the swinging arm 18 for the cycle intake valve 13 and the oil passage 4 of the swinging arm 19 for the 4-cycle exhaust valve 15
4, the other hydraulic passage 53 in the hydraulic switching valve 49 is connected to the oil passage 44 of the swinging arm 29' for the two-cycle intake valve 26 via the passage 54 in the rocker shaft 16, and It is connected to the hydraulic cylinder 31 of the two-cycle exhaust valve 28, and the hydraulic switching valve 49 is connected to the engine load detection means 55, so that when the engine load is in a load range below a certain value, the hydraulic pump 56, etc. Hydraulic pressure from the hydraulic source is supplied to the one hydraulic passage 50, and at the same time the other hydraulic passage 53 is opened to the oil tank 57, and when the load of the engine exceeds the certain value, the one hydraulic passage 50 is opened. It is constructed so that it is switched so as to simultaneously supply hydraulic pressure to the other hydraulic passage 53.

In this configuration, in a load range where the engine load is below a certain value, the hydraulic switching valve 49 switches to supply hydraulic pressure to one hydraulic passage 50 and open the other hydraulic passage 53, thereby providing two cycles. The 2-cycle intake valve 26 remains closed and does not open or close, and the 2-cycle exhaust valve 28 is also closed, while only the 4-cycle intake valve 13 and exhaust valve 15 open and close due to the rotation of the camshaft 10. , the engine is operated as a 4-cycle.

When the load of the engine exceeds the certain value, the hydraulic switching valve 49 opens one hydraulic passage 50 and switches to supply hydraulic pressure to the other hydraulic passage 53.
This time, the 4-cycle intake valve 13 and the exhaust valve 15 are inactive, while the 2-cycle intake valve 26 is in the camshaft 10
As the crankshaft rotates once, the exhaust valve 28 opens and closes once, and the engine is operated as a two-cycle operation. Intake supercharging is performed by being driven by exhaust gas discharged from the exhaust port 11.

In other words, when the engine load exceeds a certain value, the piston 3
descends due to the explosion in combustion chamber 5 and approaches its bottom dead center (
Previously, the exhaust port 11 opened into the cylinder 4 to begin releasing exhaust gas, and then when the piston 3 reached the bottom dead center, the intake valve 26 opened and supercharged air from the exhaust turbo supercharger 35 was released. is introduced while scavenging the exhaust gas inside the cylinder 4, the piston 3 moves upward, the exhaust port 11 is closed by the piston 3, and then the intake valve 2 is closed.
6 closes and enters the compression stroke, the engine is operated in two cycles and in a state of intake supercharging. Since the compression ratio is lower than the current compression ratio by the volume of the stroke from the bottom dead center of the piston 3 until the exhaust port 11 closes, non-king will not occur even if the effective compression ratio increases due to supercharging. It is.

It goes without saying that the ignition timing of the spark plug is also changed in accordance with the mutual switching between the 4-cycle and 2-cycle. Alternatively, the 4-cycle intake boat 6 and the 2-cycle intake boat 8 may be made into one at their inlet portions, and branched into two on the combustion chamber 5 side.

As described above, the present invention provides a 4-cycle intake valve, an exhaust valve, and a 2-cycle intake valve in the combustion chamber, a 2-cycle exhaust valve in the cylinder, and an intake passage to the 2-cycle intake valve. is provided with a supercharger, while the 4-cycle intake valve and exhaust valve and the 2-cycle intake valve and exhaust valve are connected to the 4-cycle intake valve and the exhaust valve when the engine load is below a certain value. The two-cycle intake valve and the exhaust valve are related to each other so that the two-cycle intake valve and the exhaust valve are operated when the engine load is equal to or higher than a certain value.
In the low load range of the engine, the engine operates in 4 cycles without supercharging, so the compression ratio in this low load range can be maximized regardless of intake supercharging, while in the high load range it operates in 2 cycles. However, compared to the 4-stroke, the 2-stroke has one explosion stroke per revolution of the crankshaft, and when compared with the same displacement, the output is larger, and since intake supercharging is performed in these 2-stroke, the engine This has the effect of reliably achieving improved output and reduced fuel consumption over the entire load range from low load to high load.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a vertical front view of the main parts of the engine, an enlarged sectional view taken along line 1-1 in FIG. 2, FIG. 2 is a plan view of the engine, and FIG. 3 is FIG. FIG. 4 is a view showing the operation switching means for the intake valve and exhaust valve, and FIG. 5 is a view showing the operating state of FIG. 4. 1... Cylinder block, 2... Cylinder head, 3... Piston, 4... Cylinder, 5...
・・Combustion chamber, 6・・4-cycle intake port, 7・
... Exhaust boat for 4-cycle, 8... Intake hoard for 2-cycle, 10... Camshaft, 11... Exhaust port for 2-cycle, 13... Intake valve for 4-cycle, 15...Exhaust valve for 4-cycle, 26...Intake valve for 2-cycle, 28...Exhaust valve for 2-cycle, 3
5...Exhaust turbo supercharger. Patent applicant Daihatsu Motor Co., Ltd. - Town map Q)

Claims (1)

[Claims] (1), 4-cycle intake valve and exhaust valve in the combustion chamber and 2
A cycle intake valve and a 2-cycle exhaust valve are provided in each cylinder, and a supercharger is provided in the intake passage to the 2-cycle intake valve, while the 4-cycle intake valve and the exhaust valve are connected to the 2-cycle intake valve. The 2-cycle intake valve and exhaust valve operate when the engine load is below a certain value, and the 2-cycle intake valve and the exhaust valve operate when the engine load is above a certain value. and an internal combustion engine operably associated with an exhaust valve.