JPS6014891Y2 - supercharged engine - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a reciprocating engine in which supercharging is performed through a third valve that opens from the end of the suction stroke to the beginning of the compression stroke.

Engines that supercharge the intake air are known in order to improve the output and fuel efficiency of automobile engines, etc., but normally the entire intake air volume is supercharged using a turbocharger, etc. The capacity of the supercharger is set based on the maximum output.

However, this would require a large capacity supercharger, so
The applicant has proposed a supercharged engine that can perform efficient supercharging with a small capacity by supercharging only a portion of the intake air through a third valve.

(For example, see Japanese Patent Application Laid-Open No. 53-746199.) To explain this with reference to FIG. 3 is attached, and the discharge air from this pump cylinder 3 is supplied to each cylinder #1 to #4 via a supercharging passage 4.

In addition to the intake valve 5 and the exhaust valve 6, each cylinder #1 to #4 is equipped with a third valve 7 exclusively for supercharging.
It begins to open near the end of closing and closes in the early to middle stages of the compression stroke.

The pump cylinder 3 has a suction valve 8 and a discharge valve 9, and performs one cycle of suction and discharge operations per rotation of the crankshaft.

Therefore, the pressurized air discharged from the pump cylinder 3 to the supercharging passage 4 is transferred to each cylinder #1 to ## as the third valve 7 opens.
4, and the third valve 7 closes just before the cylinder internal pressure rises above the supercharging pressure in the compression stroke, thereby preventing the backflow.

In this way, supercharging air is additionally supplied to the cylinder where intake air has been supplied in advance, so compared to full-volume supercharging, a small amount of supercharging has a substantially greater supercharging effect (for example, 50%
In order to perform supercharging, the capacity of the pump cylinder only needs to be the same as that of each cylinder, but in the case of full supercharging, three times the capacity of each cylinder is required.

Moreover, part of the intake air from downstream of the throttle valve 10 is transferred to the pump cylinder 3.
The supercharging air can be not only air but also a mixture with fuel. It has various advantages, such as increasing in-cylinder swirl by controlling the flow rate and direction of air inflow, which is also effective in improving combustion.

However, according to experiments conducted by the present inventors, when supercharging four cylinders with two discharge actions per engine cycle (two revolutions), the supercharged air is biased toward the cylinder where the third valve opens immediately after discharge. It was found that there is a tendency to be easily supplied.

Figure 2 shows the relationship between the lift of the discharge valve of the pump cylinder and the operating state of the third valve. This increases the ratio of supercharging air supplied to the cylinders.

In terms of crankshaft balance, this requires the connecting rod of the pump cylinder to be attached to the crankshaft to match the stroke timing of the first and fourth cylinders, and the inertia effect of pumping is used to adjust the discharge timing of the pump cylinder. This is unavoidable due to reasons such as the need to be able to send supercharged air to each cylinder by using the 3rd valve, or to supply supercharged air from the third valve near the end of the intake stroke to help strengthen the in-cylinder gas flow. It cannot be done.

If the amount of supercharging air supplied within the cylinders becomes uneven in this way, an imbalance in output between the cylinders will occur, resulting in a loss of smooth engine rotation and an increase in vibration.

In order to solve these problems, the present invention provides a supercharging passage for each cylinder independently and a valve to prevent backflow, thereby correcting the imbalance in the amount of supercharging between the cylinders. The purpose is to provide engines.

Hereinafter, embodiments of the present invention will be described based on the drawings.

As shown in FIGS. 3 and 4, the pump cylinder 3' is provided with two discharge valves 9A and 9B.
The valve opens once every two revolutions of the engine crankshaft.

For the cylinders in which the opening periods of these discharge valves 9A and 9B and the third valve 7 overlap, for example, the first discharge valve 9A, the first cylinder #1 and the third cylinder #3, and the second discharge valve For 9B, the supercharging passages 4A to 4D are separately configured as the second cylinder #2 and the fourth cylinder #4.

(However, the supercharging passage of the first cylinder #1 is 4A, hereinafter, the second
Cylinder #2 is numbered 4B, and so on.

) These supercharging passages 4A to 4D are set to have substantially the same passage volume depending on their lengths and diameters.

In order to open and close these supercharging passages 4A to 4D, as is clear from FIGS. 4 and 5, discharge valves 9A (
A partition plate 16 extending in the axial direction is interposed in the discharge port 15 of the valve 9B), and the tip of the partition plate 16 is connected to the discharge port 15 of the discharge valve 9A (9B).
The valve device is extended to the vicinity where it comes into contact with the back surface of the cap, and thereby prevents mutual backflow of the supercharging air once sent to the supercharging passages 4A to 4D when the discharge valve 9A (9B) is closed. It consists of

Note that the passages of the discharge port 15 that are partitioned by the partition plate 16 are connected to the above-mentioned supercharging passages 4A to 4D, respectively.

The present invention is constructed as described above, and for convenience of explanation,
The same reference numerals are used for substantially the same parts as in FIG.

Next, the action will be explained.

First, when the first discharge valve 9A opens, the supercharging air from the pump cylinder 3' flows into the supercharging passages of the first cylinder #1 and the third cylinder #3.
It is sent almost equally to A and 40.

When the discharge valve 9A closes, this supercharging air flows into the supercharging passages 4A and 4.
They become trapped at 0 and no longer flow back to each other.

Therefore, during this time, the third valve 7 of the first cylinder #1 opens,
Next, the third valve 7 of the third cylinder #3 opens, but unlike in the past, most of the supercharged air no longer flows only into the first cylinder #1, where the third valve 7 opens first. , 1st cylinder #
1, only the supercharging air existing in the dedicated supercharging passage 4A flows in, and then when the third valve 7 of the third cylinder #3 opens, almost the same amount of supercharging air flows from the supercharging passage 4C. Air is supplied.

(The volumes of the supercharging passages 4A and 40 are set to be the same, but considering the overlap relationship between the third valve 7 and the discharge valve 9A, the volume of the first cylinder #1 where supercharging air easily flows may be made slightly smaller.

) Similarly, when the second discharge valve 9B opens, the second cylinder #2
Almost the same amount of supercharging air is also fed into the supercharging passages 4B and 4D of the fourth cylinder #4.

In this way, substantially uniform supercharging air is supplied from the first cylinder #1 to the fourth cylinder #4, making it possible to avoid an imbalance in engine output among the cylinders.

Next, in the embodiment shown in FIG. 6, check valves 18A to 1 are used as valve devices for preventing backflow in each of the supercharging passages 4A to 4D.
In this case, the partition plate 16 as shown in FIG. 4 is not required.

Further, in the embodiment shown in FIG. 7, four discharge valves 9A to 9D are provided in the pump cylinder 3', and supercharging passages 4A to 44 are provided in the pump cylinder 3', respectively.
I am trying to connect D.

However, in this case, the opening timing of the discharge valves 9A to 9D is set so that two valves are opened at the same time (for example, the discharge valves 9A and 9C, and 9B and 9D, which correspond to the supercharging passages 4A to 9D). (determined in relation to 4D).

Although the above embodiments have all been explained using a four-cylinder engine as an example, it is easily understood that, for example, in the case of a six-cylinder engine, six supercharging passages are required.

Note that a surge tank may be interposed in the supercharging passage to average the supercharging pressure.

As explained above, according to the present invention, the supercharging passage is provided independently and a valve device that prevents backflow is installed, so that the supercharging amount imbalance between the cylinders can be corrected, and the engine output between the cylinders can be improved. This makes it possible to provide a reciprocating engine with less vibration, fuel consumption, and good output characteristics.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the conventional device, Figure 2 is its operating characteristic diagram,
Fig. 3 is a schematic diagram of the first embodiment of the present invention, Fig. 4 is a sectional view of the discharge port portion, Fig. 5 is a sectional view taken along the line I-I, and Fig. 6
7 are schematic diagrams of main parts of the second and third embodiments, respectively. 1...Intake passage, 3'...Pump cylinder, 4A to 4D...Supercharging passage, 7...Third valve, 9A to 9D... ...Discharge valve, 15...
・Discharge port, 16... Partition plate.

Claims (1)

[Scope of utility model registration request] A third valve is provided in each engine cylinder along with the intake and exhaust valves, and this third valve is opened during the compression stroke from the end of the intake stroke to additionally introduce supercharging air into the cylinder via the supercharging passage. In a supercharged engine, a pump cylinder that discharges supercharging air through a discharge valve into a supercharging passage is provided in conjunction with each cylinder, while the supercharging passage of each cylinder is formed independently from each other, and A supercharged engine characterized in that the volumes of these supercharging passages are set to be substantially the same, and further comprising a valve device that selectively opens the side of the supercharging passage connected to the pump cylinder when discharge is discharged from the pump cylinder.