JP2021121736A - Internal combustion engine - Google Patents

Abstract

To provide a five-stroke internal combustion engine which is simple in a structure, and excellent in energy collection efficiency.SOLUTION: Two combustion cylinders 3, 4 and one auxiliary cylinder 5 which is sandwiched between the two combustion cylinders are serially arranged. Exhaust ports 21 of the combustion cylinder 3, 4 are shifted to a side of the auxiliary cylinder 5 in an area at an exhaust side with a longitudinal direction center line O1 sandwiched, and also, flow-in ports 22, 23 of the auxiliary cylinder 5 are shifted to sides of the combustion cylinder 3, 4 at the exhaust side with the longitudinal direction center line O1 sandwiched. The exhaust ports 21 and the flow-in ports 22, 23 which adjoin each other communicate with each other via a take-in passage 24. Exhaust ports 25, 26 of the auxiliary cylinder 5 are located in a point of a short-side center line O2. Since the ports 20, 21 ... can secure necessary areas, a pumping loss can be suppressed. Since the take-in passage 24 can be shortened, power collection efficiency can be improved by suppressing the temperature-lowering and the expansion of a combustion gas. Since each valve is driven by two pieces of camshafts, a structure can be simplified.SELECTED DRAWING: Figure 1

Description

The present invention relates to an internal combustion engine having an auxiliary cylinder for energy recovery in addition to a combustion cylinder.

In a reciprocating internal combustion engine, the piston moves from the top dead center to the bottom dead center due to the combustion gas, but the combustion gas maintains a positive pressure even when the piston has completely moved to the bottom dead center. Energy is wasted. Therefore, an auxiliary cylinder for energy recovery is provided in addition to the combustion cylinder, the combustion gas is moved to the auxiliary cylinder when the combustion cylinder is in the exhaust stroke, and the auxiliary piston fitted in the auxiliary cylinder is driven by the combustion gas. It is proposed to do.

This internal combustion engine is also called a 5-stroke internal combustion engine or a 5-cycle internal combustion engine because a stroke of power extraction by an auxiliary cylinder is added in addition to the four strokes of the combustion cylinder.

As an example of this 5-stroke internal combustion engine, in Patent Document 1, two combustion cylinders and one auxiliary cylinder are arranged in series, and the main piston of the combustion cylinder and the auxiliary piston of the auxiliary cylinder have connecting rods, respectively. A configuration connected to the crankshaft via a shaft is disclosed. On the other hand, Patent Document 2 discloses a structure in which the main piston and the auxiliary piston are connected to a common crankshaft while the auxiliary cylinders are arranged so as to be offset from the row of combustion cylinders.

Jitsukosho 17-809 Gazette Japanese Unexamined Patent Publication No. 2013-174215

In Patent Document 1, the structure is simple because the crankshaft is shared between the combustion cylinder and the auxiliary cylinder, but the intake port and the exhaust port of the combustion cylinder and the combustion gas inflow port and the combustion gas discharge port of the auxiliary cylinder are used. Since and are lined up in series, the inner diameter of each port must be small. Therefore, it is doubtful whether the intake and exhaust in the combustion cylinder and the inflow and exhaust of the combustion gas in the auxiliary cylinder are smoothly performed.

On the other hand, if the auxiliary cylinders are displaced from the arrangement of the combustion cylinders as in Patent Document 2, it can be said that the opening area required for each port can be secured, but it is undeniable that the structure becomes complicated. In addition, since the distance between the exhaust port of the combustion cylinder and the combustion gas inflow port of the auxiliary cylinder tends to be long, expansion and temperature drop are likely to occur in the process of the combustion gas flowing from the combustion cylinder to the auxiliary cylinder. There is also a concern that the energy recovery efficiency will decrease.

The present invention has been made against the background of such a situation, and aims to improve the energy recovery efficiency while simplifying the structure as much as possible.

The internal combustion engine of the present invention is
"The first and second four-cycle combustion cylinders and one auxiliary cylinder that extracts power from the combustion gas discharged from both combustion cylinders are one auxiliary cylinder between the two combustion cylinders. Are arranged in series with the
While the intake port and the exhaust port are formed in the first and second combustion cylinders, while
The first inflow port into which the combustion gas discharged from the exhaust port provided in the first combustion cylinder flows into the auxiliary cylinder and the combustion gas discharged from the exhaust port of the second combustion cylinder flow into the auxiliary cylinder. A second inflow port and an outflow port for discharging combustion gas are formed. "
It has a basic structure.

And in the above basic configuration
"The intake ports of both combustion cylinders are formed on the intake side with a long longitudinal center line in the cylinder row direction, and the exhaust port of the combustion cylinder is on the exhaust side with the longitudinal center line in between. While it is formed at the site and near the auxiliary cylinder,
The first inflow port of the auxiliary cylinder is arranged closer to the side of the first combustion cylinder, and the second inflow port of the auxiliary cylinder is arranged closer to the side of the second combustion cylinder. "
It has the feature.

According to the present invention, since the combustion cylinder and the auxiliary cylinder are arranged in series, the valve drive structure can be simplified.

Further, in the combustion cylinder, the intake port and the exhaust port are arranged separately on one side and the other side across the longitudinal center line, so that the opening area required for the intake port and the exhaust port can be secured. .. Therefore, the combustion cylinder can make the intake and exhaust smooth, while the auxiliary cylinder can make the inflow / exhaust of the combustion gas smooth, which can contribute to the improvement of the output and the pumping loss. As a result, it can contribute to the improvement of fuel efficiency.

Further, since the inflow port of the combustion cylinder is formed in the portion close to the auxiliary cylinder and the inflow port of the auxiliary cylinder is formed in the portion close to the combustion cylinder, the exhaust port of the combustion cylinder and the auxiliary cylinder The distance from the inflow port can be as short as possible. As a result, it is possible to suppress the temperature drop and expansion of the combustion gas. As a result, the power recovery efficiency of the auxiliary cylinder can be improved, which can further contribute to the improvement of fuel efficiency.

In the figure which shows the embodiment, (A) is a schematic plan view, (B) is a sectional view taken along line BB of (A). FIG. 2 is a sectional view taken along line II-II of FIG. FIG. 3 is a sectional view taken along line III-III of FIG. FIG. 1 is a sectional view taken along line IV-IV of FIG. It is a figure which shows the stroke of each cylinder.

(1). Structure of Embodiment Next, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the internal combustion engine includes an engine body having a cylinder block 1 and a cylinder head 2 as main elements, and the engine body includes first and second combustion cylinders 3 and 4. One auxiliary cylinder 5 sandwiched between the two is formed in series.

Each of the cylinders 3, 4 and 5 has cylinder bores 6 and 7 formed in the cylinder block 1 and pent-roof type recesses 8 and 9 formed in the cylinder head 2, and the combustion cylinders 3 and 4 have. The main piston 10 is slidably fitted in the auxiliary cylinder 5, and the auxiliary piston 11 is slidably fitted in the auxiliary cylinder 5. Each of the pistons 10 and 11 is connected to one crankshaft 13 via a connecting rod 12.

As a reminder, the small end of the connecting rod 12 is connected to the pistons 10 and 11 via the piston pin 14, and the large end of the connecting rod 12 is connected to the crank arm 15 via the crank pin 16. .. Further, each journal portion 17 of the crankshaft 13 is rotatably held by the cylinder block 1 via the crank cap 18.

The volume of the auxiliary cylinder 5 is about twice the volume of the combustion cylinders 3 and 4. Therefore, the inner diameter of the auxiliary cylinder 5 is about 1.25 times the inner diameter of the combustion cylinders 3 and 4. Further, while the two main pistons 10 move up and down in synchronization, the phase of the auxiliary piston 11 is 180 ° out of phase with the phase of the main piston 10. Further, the total mass of the two main pistons 10 and the mass of one auxiliary piston 11 are the same. As a result, the rotation of the crankshaft 13 is balanced.

As shown in FIG. 1 (A), the combustion cylinders 3 and 4 of the cylinder head 2 are located on the side of the intake side surface 2a with the longitudinal center line O1 in the crank axis direction (cylinder row direction) interposed therebetween. Two intake ports 20 and one exhaust port 21 located on the exhaust side surface 2b side of the longitudinal center line O1 are open. The starting end of the intake port 20 is open to the intake side surface of the cylinder head 2, and intake air is supplied from an intake manifold (not shown).

The exhaust ports 21 of the combustion cylinders 3 and 4 are arranged closer to the auxiliary cylinder 5 with the short center line O2 orthogonal to the longitudinal center line O1 interposed therebetween. To be precise, the exhaust port 21 opens in an area closer to the auxiliary cylinder 5 and closer to the exhaust side among the four areas partitioned by the longitudinal center line O1 and the short center line O2.

The auxiliary cylinder 5 has a first inflow port 22 to which combustion gas is sent from the exhaust port 21 of the first combustion cylinder 3 and a second inflow port 23 to which combustion gas is sent from the exhaust port 21 of the second combustion cylinder 4. Is open.

The first inflow port 22 is open to a portion closer to the first combustion cylinder 3 on the side of the exhaust side surface 2b across the longitudinal center line O1 and closer to the first combustion cylinder 3 across the short center line O2 in a plan view. The 2 inflow port 23 is open to a portion closer to the second combustion cylinder 4 on the side of the exhaust side surface 2b with the longitudinal center line O1 and the short center line O2 in the plan view. The exhaust port 21 of the first combustion cylinder 3 and the first inflow port 22 of the auxiliary cylinder 5, and the exhaust port 21 of the second combustion cylinder 4 and the second inflow port 23 of the auxiliary cylinder 5 are vertically traversed. It communicates with the intake passage 24 (see FIG. 4) curved in a bow shape when viewed from the side (see FIG. 4).

Further, the auxiliary cylinder 5 is formed with two first and second discharge ports 25 and 26 for discharging combustion gas. The two discharge ports 25 and 26 are formed so as to be located on both sides of the longitudinal center line O1 and on the short center line O2. Further, the first exhaust port 25 located on the side of the intake side surface 2a has a larger diameter than the second discharge port 26 located on the side of the exhaust side surface 2b. This is because there are two inflow ports 22 and 23 on the side of the exhaust side surface 2b, and the space of the second exhaust port 26 is restricted. For example, only one discharge port can be formed around the axis of the auxiliary cylinder 5.

Each port 20, 21, 22, ... Is opened and closed by a valve. FIG. 2 shows the opening / closing structure of the intake port 20 and the exhaust port 21 in the first combustion cylinder 3. That is, like a normal internal combustion engine, the intake port 20 is opened and closed by the intake valve 28 driven by the intake camshaft 27, and the exhaust port 21 is opened and closed by the exhaust valve 30 driven by the exhaust camshaft 29. Will be done. The valves 28 and 30 are slidably fitted to the sleeve (valve guide) 31 and are urged in the closing direction by the spring 32.

Although the cam shafts 27 and 29 are simply shown in a circle in FIGS. 2 and 3, the cam portion is actually formed. Further, although the cam shafts 27 and 29 are rotatably held by the cam cap, this is also omitted. Further, although the injector faces the intake port 20, it is omitted in the drawing. As shown in FIG. 1 (B), the spark plug 33 is exposed at the top of the recess 8 in the combustion cylinders 3 and 4.

FIG. 3 shows the opening / closing structure of the discharge ports 25 and 26 in the auxiliary cylinder 5. Both discharge ports 25 and 26 are gathered in one discharge passage 34 extending in the direction of the short center line O2, and the discharge passage 34 is open to the exhaust side surface 2b of the cylinder head 2.

Then, the first discharge port 25 is opened and closed by the first discharge valve 35 driven by the intake cam shaft 27, and the second discharge port 26 is operated by the second discharge valve 36 driven by the exhaust cam shaft 29. It is opened and closed with. In this case, since there is a discharge passage 34 above the second discharge port 26 and the exposed length of the second discharge valve 36 is long, a tubular upward boss is attached to the cylinder head 2 in order to secure a fitting allowance for the sleeve 31. 37 is formed.

The inflow ports 22 and 23 of the auxiliary cylinder 5 are opened and closed by the inflow valve 38 shown in FIG. The inflow valve 38 is driven by an exhaust valve camshaft 29. As shown in FIGS. 2 and 3, a cooling water jacket 39 is formed on the cylinder head 2.

(2). Summary The movements of the cylinders 3, 4 and 5 are the same as in the conventional case, and as shown in FIG. 5, the phases of the first combustion cylinder 3 and the second combustion cylinder 4 are shifted by 360 °. While four strokes are performed in this state, combustion gas is alternately supplied to the auxiliary cylinder 5 from the first combustion cylinder 3 and the second combustion cylinder 4 at intervals of 360 °, and the combustion gas is at intervals of 360 °. Is discharged at. Therefore, a pair of cams for driving the inflow valve 38 and the discharge valves 36 and 35 are formed on the cam shafts 27 and 29 on both sides of the shaft center.

In any case, the valves 28 and 30 of the combustion cylinders 3 and 4 and the valves 35, 36 and 37 of the auxiliary cylinder 5 are driven by the two camshafts 27 and 29. Therefore, the drive structure is simple. In the present embodiment, five valves are opened and closed by the two camshafts 27 and 29, respectively, so that the load acting on the two camshafts 27 and 29 can be equalized. Therefore, the loads of both camshafts 27 and 29 on the timing chain can be equalized, and the timing chain can be smoothly rotated.

Further, the exhaust port 21 of the first combustion cylinder 3 and the first inflow port 22 of the auxiliary cylinder 5, and the exhaust port 21 of the second combustion cylinder 3 and the second inflow port 23 of the auxiliary cylinder 5 are to the minimum. Since they are close to each other, the length of the intake passage 24 can be shortened as much as possible. As a result, it is possible to suppress the temperature drop and expansion of the combustion gas and improve the work efficiency (energy recovery efficiency) of the auxiliary cylinder 5.

Further, looking at the combustion cylinders 3 and 4, since the intake port 20 and the exhaust port 21 are formed so as to be divided into one side and the other side with the longitudinal center line O1 sandwiched between them, the total intake port 20 is totaled. The area can be increased to secure the required intake air amount, and the exhaust port 21 can also secure the required opening area to smoothly exhaust the air. Therefore, fuel efficiency can be improved by reducing pumping loss.

Since only one exhaust port 21 is formed in one combustion cylinder 3 or 4, the structure is simplified and it can contribute to cost reduction. When two discharge ports 25 and 26 are formed in the auxiliary cylinder 5 as in the embodiment, the flow resistance at the time of discharging the combustion gas can be greatly reduced, and the expansion at the time of discharging can be promoted to contribute to the reduction of the pumping loss. In any case, it can contribute to the improvement of fuel efficiency.

Although the embodiments of the present invention have been described above, the present invention can be embodied in various ways. For example, it is possible to adopt a form in which a plurality of units are arranged in series with two combustion cylinders and one auxiliary cylinder as one unit.

The present invention can be embodied in an internal combustion engine (5-stroke internal combustion engine) provided with an auxiliary cylinder for power recovery. Therefore, it can be used industrially.

1 Shinrida block 2 Cylinder head 3 1st combustion cylinder 4 2nd combustion cylinder 5 Auxiliary cylinder 6,7 Cylinder bore 10 Main piston 11 Auxiliary piston 13 Crankshaft 20 Intake port 21 Exhaust port 22 1st inflow port 23 2nd inflow Port 24 Intake passage 25 1st discharge port 26 2nd discharge port 27,29 Camshaft 28 Intake valve 30 Exhaust valve 34 Discharge passage 35,36 Discharge valve 38 Inflow valve O1 Longitudinal center line O2 Short center line

Claims (1)

The first and second four-cycle combustion cylinders and one auxiliary cylinder that extracts power from the combustion gas discharged from both combustion cylinders have one auxiliary cylinder between the two combustion cylinders. Arranged in series in a sandwiched state,
While the intake port and the exhaust port are formed in the first and second combustion cylinders, while
The first inflow port into which the combustion gas discharged from the exhaust port provided in the first combustion cylinder flows into the auxiliary cylinder and the combustion gas discharged from the exhaust port of the second combustion cylinder flow into the auxiliary cylinder. It has a configuration in which a second inflow port and an outflow port for discharging combustion gas are formed.
The intake ports of both combustion cylinders are formed on the intake side with a long longitudinal center line in the cylinder row direction, and the exhaust port of the combustion cylinder is on the exhaust side with the longitudinal center line in between. While it is formed near the auxiliary cylinder,
The first inflow port of the auxiliary cylinder is arranged closer to the side of the first combustion cylinder, and the second inflow port of the auxiliary cylinder is arranged closer to the side of the second combustion cylinder.
Internal combustion engine.

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