JP2976800B2 - Internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine for supplying air to a cylinder for scavenging and / or supercharging.

[0002]

2. Description of the Related Art In a conventional internal combustion engine for a vehicle, especially a large vehicle such as a truck, a combustion chamber cavity is formed in the top surface of a piston, and fuel is injected into the combustion chamber cavity to generate explosive combustion. Such direct injection diesel engines are widely used. In this type of internal combustion engine, when the exhaust stroke ends and the intake stroke starts, a considerable amount of exhaust gas inevitably remains in the combustion chamber cavity. Since the residual exhaust gas in the combustion chamber cavity has a high temperature, the residual exhaust gas is mixed with the air sucked into the cylinder in the intake stroke following the exhaust stroke, thereby causing a significant increase in the intake air temperature. In the case of a normal direct injection diesel engine for trucks, the temperature rise of fresh air sucked by the residual exhaust gas in the combustion chamber cavity is approximately 40 ° C.
Reach a degree. Such fresh air temperature increase of the reduction of charging efficiency Needless to say, therefore there is a problem of causing a decrease in engine output, also increased _the amount of NO _x in the exhaust gas due to an increase in the maximum combustion temperature in the explosion stroke Further, there is a disadvantage that the smoke property is deteriorated.

Conventionally, each cylinder of an internal combustion engine is provided with a third valve separate from a normal intake valve and an exhaust valve, and compressed air is injected into the cylinder from the third valve for the purpose of scavenging, supercharging, and the like. Such a device is disclosed in JP-A-4-31622 and JP-A-1-163420. In these proposed internal combustion engines, normal intake and exhaust valves,
Intake and exhaust ports cooperating with these intake and exhaust valves,
Since the fuel injection valve, the cooling water chamber having a complicated shape, and the like are provided and the third valve must be additionally provided in a cylinder head having an extremely complicated structure, the third valve is required. The increase in cost due to the addition of itself and the increase in cost due to the increasingly complicated structure of the cylinder head overlap, and there is a problem that a considerable increase in manufacturing cost cannot be avoided. Furthermore, in these proposed configurations, compressed air is continuously supplied from the third valve into the cylinder during the period in which the third valve is open for scavenging and supercharging.
Since the consumption of the compressed air is large and the required capacity of the compressed air source including the air compressor is increased, the production cost and the running cost of the air supply system are disadvantageously increased.

[0004]

SUMMARY OF THE INVENTION The present invention provides for efficient exhaust gas cleaning and / or supercharging without providing a third valve separate from normal exhaust and intake valves. Accordingly, it is an object of the present invention to provide a simple and inexpensive internal combustion engine capable of improving engine output and improving exhaust gas performance.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and has an intake port provided in a cylinder head of an internal combustion engine, and a combustion chamber of the intake port mounted on the cylinder head. An intake valve for opening and closing the opening on the side, a compressed air source for storing compressed air, a shock wave transmission having one end opened into an intake port upstream of a valve head portion of the intake valve and the other end connected to the compressed air source passage, the valve device for Shokkuuebu generating interposed in the Shokkuuebu transfer passage, and a control device for outputting a signal for momentarily opening and closing the valve device in accordance with an operating state of the internal combustion engine, the Shokkuuebu transfer passage Is sucking
The area of the gap between the umbrella and the intake port when the air valve is open
Sv, and the area of the shockwave transmission passage is Sp
And set the area in the transmission passage so that Sv <Sp.
The present invention proposes an internal combustion engine characterized by the above.
In the present invention, the control device preferably includes at least a load sensor for detecting a load and a rotation speed sensor for detecting a rotation speed of a crankshaft, as means for detecting an engine operating state. Further, it is preferable that the control device momentarily controls the opening and closing of the valve device so as to supply a scavenging wave for scavenging when the engine operating state is at full load and the intake and exhaust valves are overlapped. It is preferable that the control device momentarily controls the opening and closing of the valve device so as to supply a supercharging shock wave before the intake valve closes when the engine operating state is at full load. Further , the shock wave transmission passage is configured so that a tip end of the shock wave transmission passage is directed to the umbrella portion, a high wave is formed around the umbrella portion of the intake valve, and high-pressure air is pushed from the gap. Is preferred.
Further, the shock wave transmission passage forms a high wave in the passage by forming a constricted portion at a tip portion of the passage, and jet flow is directed toward a gap between the intake valve head portion and the intake port opening. Is advantageously configured to inject. Further, the shock wave transmission passage has a tip end of the passage directed to the intake valve head in the cylinder block so as to guide the wave motion to a gap between the intake valve head and the intake port opening. Preferably, they are provided. Further, in the present invention, it is advantageous that the valve device is an electromagnetic valve, and the control device can open and close the valve device at the time of full load operation of the engine and at the time of high load operation close thereto. desirable.

[0006]

According to the present invention, the valve device interposed in the shock wave transmission passage is instantaneously provided at an appropriate timing according to the operating state of the internal combustion engine by the control device, that is, at the end of the exhaust stroke of each cylinder. When opened, the high-pressure air stored in the compressed air source jets into the shock wave transmission passage in a very small amount to generate a shock wave. The generated shock wave propagates in the shock wave transmission passage at high speed, reaches the intake port upstream of the valve head of the intake valve, and forms a high-pressure region in the intake port upstream of the valve head of the intake valve. By forming a high-pressure region in the intake port, the intake air in the intake port downstream therefrom is forcibly pumped into the cylinder, and the exhaust gas remaining in the cylinder is discharged from the exhaust valve which is still open. It is pushed into the exhaust port for effective cleaning. Since the scavenging is performed by the wave pressure of the shock wave generated by instantaneously opening and closing the valve device, the consumption of high-pressure air is small, and the capacity of the compressed air source is sufficiently small. Also, by instantly opening the valve device at the end of the intake stroke,
By utilizing the wave pressure of the shock wave, the intake air in the intake port is forcibly pressed into the cylinder to obtain a supercharging effect. In addition, the above scavenging and / or supercharging
It is particularly effective to perform the operation at the time of full load operation in which the output of the engine is particularly required or at the time of high load operation in the vicinity thereof. Thereby, the consumption of the compressed air can be further reduced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the accompanying drawings. In the drawing, reference numeral 10 indicates a piston of a direct injection diesel engine for a truck, which piston has a combustion chamber cavity 12 recessed on the top surface thereof.
The piston 10 is connected to a crankshaft (not shown) via a connecting rod 14 and reciprocates in a cylinder 18 formed in a crankcase 16.

The cylinder head 2 is placed on the crankcase 16.
The cylinder head is provided with an exhaust port 22 and an intake port 24. Exhaust port 22
An exhaust valve 26 is provided near an open end of the intake port 24 communicating with the cylinder 18, and an intake valve 28 is provided near an open end of the intake port 24 communicating with the cylinder 18. Further, the combustion chamber cavity 1 is provided in the cylinder head 20.
2, a fuel injection valve 30 is provided, and a shock wave transmission passage 32 whose one end is open to an upstream portion of the intake valve valve head portion of the intake port 24 is provided. (Note that, in FIG. 1, the exhaust port 22, the intake port 24, the exhaust valve 26, the intake valve 28, the fuel injection valve 30, and the shockwave transmission passage 32 are illustrated on the same plane for convenience, but technically good. As is known, the valve members, ports and passages are generally located in different planes on the cylinder head portion above the cylinder 18 so as not to interfere with each other, and the fuel The injection valve 30
Although it is drawn substantially perpendicular to the top surface of the piston 10, it is often arranged at an appropriate inclination with respect to the piston top surface mainly due to the arrangement space. )

The opening end 32 'of the shock wave transmission passage 32 in the intake port 24 is preferably provided so as to point toward the valve head of the intake valve 28 as shown in the figure. The other end is connected to an air tank 36 as a source of compressed air via a valve device 34 for generating shock waves. The air tank 36 is filled with high-pressure (preferably, a pressure of 5 atm or more) compressed air discharged from an air compressor 38 driven in conjunction with the crankshaft of the engine. Alternatively, the compressed air discharged from the air compressor 38 can be directly supplied to the valve device 34 for generating shock waves. In this case, a suitable accumulator (for example, an accumulator for maintaining the line pressure) is provided on the discharge side of the air compressor 38. (A nitrogen gas filled rubber bag type accumulator, a piston type accumulator, etc.).

[0010] The valve device 34 for generating the shock wave.
Has an excellent responsiveness to an opening / closing command signal, in other words, an appropriate valve device that opens and closes instantaneously upon receiving the signal is adopted. A valve member 44 that cooperates with the valve seat 42 of the valve member, a valve spring 46 that constantly biases the valve member 44 in the closing direction,
The solenoid 4 drives the valve member 44 in the opening direction against the valve closing force of the valve spring 46 by being urged.
The valve housing 40 is provided with an air inlet 50 connected to the compressed air source 36.

[0011] The solenoid 48 is the rotation speed Ne of the engine, an engine load Le, crank angle theta _c, etc., by receiving a signal relating to the operating state of the engine, with the solenoid 48 of Shokkuuebu generating valve 34 of each cylinder Controlled by a controller or controller 52 that provides an energizing or deactivating output signal.

In the above arrangement, the valve device 34 for Shokkuuebu generation takes a valve lift h _v the vertical axis, the valve lift diagram of Figure 2 shows taking crank angle theta _c on the horizontal axis, the exhaust stroke The end period, ie, the lift curve h of the exhaust valve 26
_ex and the lift curve h _in of the intake valve 28 overlap, and at least one or both of the end of the intake stroke, that is, the period B in the figure, or both, is instantaneously opened and closed by the output signal of the control device 52. Is done. The period A
And B, the instantaneous opening and closing of the valve device 34 is preferably performed in or near full-power operation in which the output of the engine is particularly required. However, it is of course possible to open and close the valve device 34 in all operating states of the engine as desired.

In the above-mentioned period A or B, when an energizing output is supplied from the control device 52 to the solenoid 48,
The valve member 44 is displaced to the open position as shown in FIG. 1, and the high-pressure compressed air of the compressed air source 36 flows into the shock wave transmission passage 32 instantaneously, so that a shock wave is generated. The generated shock wave has an open end 32 '.
From the intake port 24 to generate a high-pressure region in the intake port at the upstream portion of the valve head portion of the intake valve 28.

In the valve wrap period A at the end of the exhaust stroke due to the occurrence of the high pressure region, the intake air in the intake pipe 24 is indicated by a dotted arrow in FIG. 1 due to the pressure difference between the low pressure of the exhaust port 22 and the high pressure region. As described above, the exhaust gas forcedly fed into the combustion chamber cavity 12 and remaining in the combustion chamber cavity 12 is effectively cleaned. Since the residual exhaust gas in the combustion chamber cavity 12 is of course high in temperature, by effectively cleaning the exhaust gas, it is possible to effectively prevent a rise in the temperature of the intake air taken in during the intake stroke, to improve the volumetric efficiency, and therefore to improve the engine output. Can be improved. Furthermore, since the intake air temperature at the end of compression decreases,
Reducing the maximum temperature and connection time of the combustion gases, it is possible to reduce the NO _x and smoke in the exhaust gas. In order to generate the high pressure region in the intake port by the shock wave, the shock wave is applied to the open end 3 of the transmission passage 32.
2 ', the opening area of the intake valve 28 is S
v, and when the cross-sectional area of the open end of the shockwave transmission passage 32 is Sp, Sv <Sp is set. Also,
Orientation of the transfer passage 32 in the vicinity of the open end, the traveling direction of Shokkuuebu in other words, it is effective to direct the valve head of the intake valve 28. Furthermore, it is advantageous in that the opening end of the shock wave transmission passage 32 is formed to have a narrowed tapered shape, and the pressure in the high pressure region is increased.

Further, at the end B of the intake stroke in FIG. 2, the high pressure region is generated in the intake port 24, whereby the intake air in the intake port can be forcibly pumped into the cylinder. The effect is obtained. As is well known in the art, supercharging results in a corresponding increase in engine power.

According to the above configuration, it is not necessary to provide the third valve in the cylinder head 20 which is structurally extremely complicated, and the valve device 34 can be provided outside the cylinder head 20. There is an advantage that it can be manufactured at low cost without increasing the cost, and since the generation of the high-pressure region in the intake port 24 is based on the shock wave caused by the instantaneous opening of the valve device 34, the valve which is once opened The device 34 has the advantage that it is immediately closed by the control device 52, so that the consumption of compressed air is very low. Further, the valve device 34 is momentarily opened and closed in at least one or both of the exhaust stroke end A and the intake stroke end B only at the time of full power operation in which engine output is required or at the time of high load operation in the vicinity thereof. This has the added advantage that the consumption of compressed air can be further reduced.

In the above embodiment, the piston 1
Although the case where the combustion chamber cavity 12 recessed on the top surface of the zero is a toroidal combustion chamber is illustrated, the present invention is not limited to this, and a Hesselmann-type combustion chamber, a Leyland-type combustion chamber, etc. The present invention can be widely applied to various direct injection diesel engines having a combustion chamber cavity of an arbitrary shape such as a dish shape. Further, although a solenoid valve using a solenoid 48 as an actuator is shown as the shock wave generating valve device 34, a hydraulic or compressed air operated valve device which has excellent responsiveness and can be opened and closed instantaneously may be appropriately employed. it can.

[0018]

As described above, the internal combustion engine according to the present invention has an intake port provided on a cylinder head of the internal combustion engine, and is mounted on the cylinder head and opens and closes an opening on the combustion chamber side of the intake port. An intake valve, a compressed air source for storing compressed air, one end of which opens into an intake port upstream of the valve head portion of the intake valve and the other end communicates with the compressed air source. the valve device interposed the Shokkuuebu for generating, and a control device for outputting a signal for momentarily opening and closing the valve device in accordance with an operating state of the internal combustion engine, the shock
The wave transmission passage is located between the umbrella and the intake port when the intake valve is open.
Sv is the area of the gap with the opening, and shock wave transmission
Assuming that the area of the passage is Sp, Sv <Sp
The area within the transmission passage is set , and the exhaust gas cleaning and / or supercharging can be effectively performed by a simple and inexpensive structure. This is industrially beneficial because it can achieve improved exhaust gas performance.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention.

FIG. 2 is a valve lift diagram of the engine shown in FIG. 1;

[Explanation of symbols]

10: piston, 20: cylinder head, 22: exhaust port, 24: intake port, 26: exhaust valve, 28: intake valve, 32: shock wave transmission passage, 34: valve device,
36 ... Compressed air source, 52 ... Control device.

Claims (3)

(57) [Claims] 1. An intake port provided in a cylinder head of an internal combustion engine, an intake valve mounted on the cylinder head to open and close an opening of the intake port on the combustion chamber side, a compressed air source for storing compressed air, and one end thereof. A shock wave transmission passage that opens into an intake port upstream of a valve head portion of the intake valve and has the other end connected to the compressed air source, a valve device for generating a shock wave interposed in the shock wave transmission passage, and the internal combustion engine A control device that outputs a signal for instantaneously opening and closing the valve device according to the operating state of the engine ;
The shock wave transmission passage is connected to the umbrella when the intake valve is opened.
The area of the gap with the intake port opening is Sv,
Assuming that the area of the probe transmission passage is Sp, Sv <Sp
An internal combustion engine characterized in that the area within the transmission passage is set as described above . 2. The control device according to claim 1, wherein the control device includes at least a load sensor for detecting a load and a rotation speed sensor for detecting a rotation speed of a crankshaft, as means for detecting an engine operating state. 2. The internal combustion engine according to 1. 3. The control device according to claim 1, wherein when the engine operating state is full load and the intake and exhaust valves overlap, the valve device is momentarily opened and closed to supply a scavenging shock wave. The internal combustion engine according to claim 1 or 2, wherein: