JP2011052665A - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a combustion performance by generating a good air-fuel mixture in an internal combustion engine. <P>SOLUTION: The internal combustion engine is formed with tangential ports 17a and helical ports 17b having different shapes and communicating with a combustion chamber 16, and is provided with CNG injectors 27 for injecting a CNG fuel and diesel oil injectors 33 for injecting a diesel oil. The CNG injectors 27 inject the CNG fuel into the tangential ports 17a and the light oil injectors 33 inject the light oil into the combustion chamber 16. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an internal combustion engine having a fuel injection valve capable of injecting gaseous fuel and liquid fuel.

  As an internal combustion engine capable of injecting gaseous fuel and liquid fuel, for example, there is one described in Patent Document 1 below. The dual fuel diesel engine described in Patent Document 1 is provided with a gas cylinder, a regulator that adjusts the gas pressure as a pressure drop, a gas injector that injects gas into an intake port, and a liquid fuel as a gas fuel supply system. As a supply system, a fuel tank, a fuel injection pump that boosts and adjusts the liquid pressure, and a liquid injector that injects liquid into the cylinder are provided, and gas fuel is supplied during the intake stroke from when the exhaust valve is closed until the intake valve is closed. Is injected and then liquid fuel is injected to ignite and burn.

Japanese Unexamined Patent Publication No. 07-011983

  In the diesel engine having the gas fuel supply system and the liquid fuel supply system described above, gas fuel is used as the fuel for securing the output, and liquid fuel is used for securing the ignitability of the gas fuel. . That is, gaseous fuel is injected into the air and mixed while introducing both into the cylinder to generate an air-fuel mixture, and liquid fuel is injected into the air-fuel mixture for compression ignition. In this case, it is necessary to adjust the injection amount of the gas fuel according to the required output of the engine. However, in this conventional dual fuel diesel engine, the gas fuel is injected into the intake port at a predetermined pressure. When the injection amount of the gas fuel increases, it becomes difficult to perform the intake synchronous injection properly, and the mixing is performed. There is a risk that the gas generation will be insufficient.

  An object of the present invention is to solve such a problem, and an object of the present invention is to provide an internal combustion engine capable of generating a favorable air-fuel mixture and improving combustibility.

  In order to solve the above-described problems and achieve the object, an internal combustion engine of the present invention includes a cylinder formed by an internal combustion engine body and a piston, a plurality of intake ports having different shapes communicating with the cylinder, and the intake air An intake valve capable of opening and closing a port, an exhaust port communicating with the cylinder, an exhaust valve capable of opening and closing the exhaust port, a gaseous fuel injection valve capable of injecting gaseous fuel into the intake port, and liquid fuel in the cylinder An internal combustion engine including a liquid fuel injection valve capable of injecting fuel gas is characterized in that the gaseous fuel injection valve injects gaseous fuel into a part of the plurality of intake ports.

  In the internal combustion engine of the present invention, the plurality of intake ports have at least two types of ports of a tangential port, a helical port, and a straight port.

  In the internal combustion engine of the present invention, the plurality of intake ports are a tangential port and a helical port, and the gaseous fuel injection valve injects gaseous fuel into the tangential port.

  The internal combustion engine of the present invention has a plurality of cylinders, the same number of the gaseous fuel injection valves are provided for each cylinder, the intake pipe and the plurality of intake ports are communicated by an intake manifold, and the gaseous fuel injection valves Is mounted on the intake manifold and extends from the injection port toward a part of the plurality of intake ports.

  The internal combustion engine of the present invention is characterized in that an injection position changing means capable of changing an injection position of the gaseous fuel injection valve among the plurality of intake ports is provided.

  The internal combustion engine of the present invention is characterized in that a control means for controlling the injection position changing means in accordance with the operating state of the internal combustion engine is provided.

  According to the internal combustion engine of the present invention, a plurality of intake ports having different shapes communicating with the cylinder are provided, and a gas fuel injection valve capable of injecting gaseous fuel is provided in the intake port, and a plurality of intake ports are provided by the gas fuel injection valves. Gas fuel can be injected into a part of the intake port. Accordingly, it is possible to inject gaseous fuel into the intake port having an optimal shape, and it is possible to generate an air-fuel mixture in which air and fuel are well mixed. As a result, it is possible to improve combustibility.

FIG. 1 is a schematic plan view showing an internal combustion engine according to Embodiment 1 of the present invention. FIG. 2 is a schematic sectional view showing the internal combustion engine of the first embodiment. FIG. 3 is a schematic diagram illustrating an intake port in the internal combustion engine of the first embodiment. FIG. 4 is a schematic plan view showing the internal combustion engine according to the second embodiment of the present invention. FIG. 5 is a schematic plan view showing an internal combustion engine according to Embodiment 3 of the present invention. FIG. 6 is a schematic plan view showing an internal combustion engine according to Embodiment 4 of the present invention.

  Embodiments of an internal combustion engine according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this Example.

  1 is a schematic plan view illustrating an internal combustion engine according to a first embodiment of the present invention, FIG. 2 is a schematic cross-sectional view illustrating the internal combustion engine according to the first embodiment, and FIG. 3 illustrates an intake port in the internal combustion engine according to the first embodiment. FIG.

  The internal combustion engine of the first embodiment will be described by applying this internal combustion engine to a diesel engine. In the diesel engine of the first embodiment, as shown in FIGS. 1 to 3, a cylinder head 12 is bolted on the cylinder block 11, and the engine body is configured by the cylinder block 11 and the cylinder head 12. . Four cylinder bores 13 are formed along the vertical direction so as to be arranged in series along the longitudinal direction of the cylinder block 11, and pistons 14 are fitted to the respective cylinder bores 13 so as to be vertically movable. A crankcase (not shown) is fastened to the lower portion of the cylinder block 11, and a crankshaft is rotatably supported in the crankcase. Each piston 14 is connected to the crankshaft via a connecting rod 15. .

  The four combustion chambers (cylinders) 16 are defined by a cavity (concave portion) 14 a formed on the wall surface of the cylinder bore 13, the lower surface of the cylinder head 12, and the top surface of the piston 14 in the cylinder block 11. An intake port 17 and an exhaust port 18 are formed on the lower surface of the cylinder head 12 so as to communicate with the combustion chambers 16, respectively. The lower ends of the valve 19 and the exhaust valve 20 are respectively arranged. The intake valve 19 and the exhaust valve 20 are supported by the cylinder head 12 so as to be movable in the axial direction, and are urged and supported in a direction (upward in FIG. 2) for closing the intake port 17 and the exhaust port 18. ing. An intake camshaft 21 and an exhaust camshaft 22 are rotatably supported by the cylinder head 12. The intake cam and the exhaust cam formed on the intake camshaft 21 and the exhaust camshaft 22 are connected to the intake valve 19 and the intake cam 19. It is in contact with the upper end of the exhaust valve 20.

  In this embodiment, the intake port 17 provided for each combustion chamber 16 is composed of a plurality of intake ports having different shapes. Specifically, each intake port 17 includes a tangential port 17a and a helical port 17b, is formed substantially parallel to the cylinder head 12 in the horizontal direction, and an intake valve 19 with respect to each port 17a, 17b. Is provided.

  The tangential port 17a is generally used to form a large swirl in the entire cylinder by supplying the intake air supplied into the combustion chamber 16 in the cylinder tangential direction in order to achieve homogeneous combustion of the air-fuel mixture. When the swirl flow is sustained until the end of the compression stroke, a homogeneous mixture is generated due to the turbulence of the air flow generated by the increase in the swirl flow at the ignition timing, and the combustion speed is increased to achieve good homogeneous combustion Is possible. On the other hand, the helical port 17b generally forms a strong partial swirl flow at the time of exiting the intake port 17 by intake air supplied into the combustion chamber 16 in order to realize stratified combustion of the air-fuel mixture. A swirl flow is generated in the combustion chamber 16 to activate the intake air flow, and a rich mixture layer that is easy to ignite at the center of the combustion chamber 16 by direct injection of fuel into the combustion chamber 16 or the like. It is possible to form and realize ultra lean combustion.

  Further, the exhaust port 18 provided for each combustion chamber 16 includes two exhaust ports 18a and 18b having the same shape. Further, although not shown, an endless timing chain is wound around the crankshaft sprocket fixed to the crankshaft and the camshaft sprockets fixed to the intake camshaft 21 and the exhaust camshaft 22 respectively. The crankshaft, the intake camshaft 21 and the exhaust camshaft 22 can be interlocked.

  Therefore, when the intake camshaft 21 and the exhaust camshaft 22 rotate in synchronization with the crankshaft, the intake cam and the exhaust cam move up and down the intake valve 19 and the exhaust valve 20 at a predetermined timing, so that the intake port 17 (17a , 17b) and the exhaust port 18 (18a, 18b) can be opened and closed to allow the intake port 17 and the combustion chamber 16 to communicate with the combustion chamber 16 and the exhaust port 18, respectively. In this case, the intake camshaft 21 and the exhaust camshaft 22 are set to rotate once (360 degrees) while the crankshaft rotates twice (720 degrees). Therefore, the diesel engine executes four strokes of the intake stroke, the compression stroke, the expansion stroke, and the exhaust stroke while the crankshaft rotates twice. At this time, the intake camshaft 21 and the exhaust camshaft 22 rotate once. Will be.

  An intake manifold 23 is fastened to the side surface of the cylinder head 12 on the intake port 17 side. An intake pipe 24 is connected to the intake manifold 23, and an air cleaner 25 is attached to an air intake port of the intake pipe 24. Yes. A throttle valve 26 is provided on the downstream side of the air cleaner 25.

  In this embodiment, a gas fuel injection valve capable of injecting gaseous fuel into the intake port 17 (17a, 17b) and a liquid fuel injection valve capable of injecting liquid fuel into the combustion chamber 16 are provided. The fuel injection valve can inject gaseous fuel into a part of the tangential port 17a and the helical port 17b, that is, the tangential port 17a. In this case, a compressed natural gas (CNG) fuel is applied as the gaseous fuel, and light oil is applied as the liquid fuel.

  That is, in the intake manifold 23, four CNG injectors (gaseous fuel injection valves) 27 corresponding to the four combustion chambers 16 are provided in series at predetermined intervals. Each of the CNG injectors 27 is connected to a CNG delivery pipe 28 arranged at the base end side above the CNG injector 27, and the tip end side enters the intake manifold 23. Each CNG injector 27 is connected with a CNG injection pipe 29 at the tip, and each CNG injection pipe 29 extends in the intake manifold 23 toward each intake port 17 of the cylinder head 12, and the tip is provided with each tip. It is inserted into the tangential port 17a.

  The CNG delivery pipe 28 is disposed above the intake manifold 23 and on the connection side of the intake pipe 24, and is connected to the CNG cylinder 31 by the CNG supply pipe 30. A pressure regulator 32 is provided on the CNG supply pipe 30. The pressure regulator 32 decreases the pressure of the CNG stored in the CNG cylinder 31 and adjusts it to a predetermined supply pressure.

  In this case, in order to evenly distribute and supply CNG fuel to each combustion chamber 16 and to ensure stable combustion, the dynamic range of the CNG fuel supply system is the intake stroke after the exhaust valve 20 is closed in the intake stroke. It is set to be able to supply the requested amount of CNG fuel until the valve 19 is closed. Specifically, if the supply pressure of CNG fuel is constant, the requested CNG fuel amount can be injected within a predetermined injection timing (injection period) even if the supply amount varies from a small flow rate to a large flow rate. It is assumed that the CNG injector 27 has excellent response characteristics. When the supply amount fluctuates from a small flow rate to a large flow rate, the ECU 41 controls the pressure regulator 32 so that the CNG fuel 27 can inject the required CNG fuel amount within a predetermined injection timing (injection period). Thus, the supply pressure of CNG fuel can be adjusted.

  Therefore, when the pressure regulator 32 adjusts the CNG pressure of the CNG cylinder 31 to a predetermined supply pressure and then supplies the CNG delivery pipe 28 through the CNG supply pipe 30, the CNG fuel is supplied to the CNG delivery pipe 28 at a predetermined pressure. Is maintained, and each CNG injector 27 is operated, whereby CNG fuel can be injected into each tangential port 17a via the CNG injection pipe 29.

  The cylinder head 12 is provided with four light oil injectors (liquid fuel injection valves) 33 in series at predetermined intervals located above the center of each combustion chamber 16. Each of the light oil injectors 33 is connected to the common rail 34 disposed on the upper end side of the light oil injector 33, and faces the combustion chamber 16 on the front end side. The common rail 34 is disposed above the cylinder head 12 and is connected to a light oil tank 36 by a light oil supply pipe 35. A high pressure pump 37 is provided in the light oil supply pipe 35. The high pressure pump 37 increases the pressure of light oil stored in the light oil tank 36 and adjusts it to a predetermined supply pressure.

  Accordingly, when the high pressure pump 37 adjusts the light oil pressure in the light oil tank 36 to a predetermined supply pressure and then supplies the common rail 34 through the light oil supply pipe 35, the light oil fuel having a predetermined pressure is maintained in the common rail 34. Light oil fuel can be injected into each combustion chamber 16 by operating each light oil injector 33.

  On the other hand, an exhaust manifold 38 is fastened to the side surface of the cylinder head 12 on the exhaust port 18 side, and an exhaust pipe 39 is connected to the exhaust manifold 38. The exhaust pipe 39 is contained in the exhaust gas. A catalyst 40 for purifying harmful substances is provided. In this case, the catalyst 40 is, for example, DPNR, and collects particulates (PM: particulates) in the exhaust gas, particularly black smoke, and stores NOx in the exhaust gas when the exhaust air-fuel ratio is lean. It is desirable that the stored NOx is released when the oxygen concentration in the exhaust gas is reduced and is reduced by the added fuel (reducing agent).

  Although not shown, it is desirable to provide an exhaust gas recirculation (EGR) device that returns exhaust gas to the intake system. This EGR device connects an exhaust pipe 39 and an intake pipe 24 to recirculate a part of the exhaust gas to the intake system, an EGR valve provided in the EGR path, and an EGR path. It comprises an EGR cooler that cools the exhaust gas.

  By the way, the vehicle is equipped with an electronic control unit (ECU) 41 that controls the diesel engine of this embodiment. The ECU 41 can control the fuel injection amount, fuel injection timing, and the like by the injectors 27 and 33, and is based on the engine operating state such as the detected intake air amount, accelerator opening, engine speed, and cooling water temperature. The throttle opening, fuel injection amount, injection timing, etc. are determined.

  That is, an air flow sensor 42 is mounted on the upstream side of the intake pipe 24 and outputs the measured intake air amount to the ECU 41. The accelerator pedal is provided with an accelerator position sensor 43, which outputs the current accelerator opening to the ECU 41. The crankshaft is provided with a crank angle sensor 44 and outputs the detected crank angle to the ECU 41. The ECU 41 discriminates an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke in each cylinder based on the crank angle. Calculate the engine speed. Further, the cylinder block 11 is provided with a water temperature sensor 45 and outputs the detected engine cooling water temperature to the ECU 41.

  An air-fuel ratio (A / F) sensor 46 is provided upstream of the catalyst 40 in the exhaust pipe 39. The A / F sensor 46 detects the exhaust air / fuel ratio (oxygen amount) of the exhaust gas exhausted from the combustion chamber 16 through the exhaust port 18 and the exhaust manifold 38 to the exhaust pipe 39, and outputs the detected exhaust air / fuel ratio to the ECU 41. is doing. The ECU 41 corrects the fuel injection amount by feeding back the exhaust air-fuel ratio detected by the A / F sensor 46 and comparing it with the target air-fuel ratio set according to the engine operating state.

  Here, the operation of the diesel engine of the first embodiment will be described.

  In the diesel engine of the first embodiment, as shown in FIGS. 1 and 2, the ECU 41 is an engine such as the intake air amount detected by the various sensors 42, 43, 44, 45, the accelerator opening, the engine speed, and the cooling water temperature. Based on the operating state, the injection amount and fuel injection timing of CNG fuel and light oil fuel by the CNG injector 27 and light oil injector 33 are determined.

  That is, the ECU 41 controls the pressure regulator 32 according to the engine operating state, adjusts the CNG pressure of the CNG cylinder 31 to a predetermined supply pressure, and supplies it to the CNG delivery pipe 28. The ECU 41 controls each CNG injector 27 and injects CNG fuel from the CNG injection pipe 29 to the tangential port 17a in each intake port 17 at a predetermined timing. In this case, the fuel injection timing of the CNG injector 27 is set during the intake stroke from when the exhaust valve 20 is closed to when the intake valve 19 is closed.

  Then, the CNG fuel injected into the tangential port 17a is taken into the combustion chamber 16 along with the air taken into the tangential port 17a through the intake pipe 24 through the air cleaner 25. At this time, the mixture of CNG fuel and air supplied to the combustion chamber 16 through the tangential port 17a becomes a large swirl flow in the cylinder. Thereafter, when the piston 14 moves up to the compression stroke, the swirl flow of the air-fuel mixture is maintained until the end of the compression stroke. Note that the air introduced from the intake pipe 24 through the helical port 17b into the combustion chamber 16 is ejected from the helical port 17b as a strong swirl flow.

  The ECU 41 controls each light oil injector 33 and injects light oil fuel into each combustion chamber 16 at a predetermined timing. In this case, the light oil fuel is injected toward the cavity 14a of the piston 14, and is collected at the center thereof. Thereafter, when the inside of the combustion chamber 16 reaches a predetermined pressure, the mixture of CNG fuel and air is ignited with this light oil fuel as a base point, and at this ignition timing, due to the turbulence of the air flow generated by the increase of the swirl flow A homogeneous mixture is generated and the combustion rate is increased to achieve good homogeneous combustion.

  As described above, in the internal combustion engine of the first embodiment, the tangential port 17a and the helical port 17b having different shapes communicating with the combustion chamber 16 are formed, the CNG injector 27 capable of injecting CNG fuel, and the light oil fuel. The CNG injector 27 injects CNG fuel into the tangential port 17 a, and the light oil injector 33 injects light oil fuel into the combustion chamber 16.

  Therefore, by injecting CNG fuel into the tangential port 17a, air and CNG fuel are introduced into the combustion chamber 16 in a swirl flow, and air and CNG fuel are appropriately mixed, A good air-fuel mixture can be generated, and particularly in a high load operation of the engine, good homogeneous combustion can be realized and the combustibility can be improved.

  In the internal combustion engine of the first embodiment, the intake pipe 24 and the intake port 17 (17a, 17b) communicating with each combustion chamber 16 are communicated by the intake manifold 23, and the CNG injector 27 is attached to the intake manifold 23. An injection port at the tip of the CNG injection pipe 29 extends toward the tangential port 17a. Therefore, the CNG fuel can be appropriately injected into the tangential port 17a, and the CNG fuel supply system can be efficiently arranged without interfering with the light oil fuel supply system.

  In the internal combustion engine of the first embodiment, the dynamic range of the CNG fuel supply system is improved by using the CNG injector 27 having response characteristics or by adjusting the supply pressure of the CNG fuel by the pressure regulator 32. . Accordingly, during the intake stroke, the requested amount of CNG fuel can be properly supplied from when the exhaust valve 20 is closed to when the intake valve 19 is closed, and CNG fuel is evenly distributed to each combustion chamber 16. Supply and ensure stable combustion.

  FIG. 4 is a schematic plan view showing the internal combustion engine according to the second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the diesel engine of the second embodiment, as shown in FIG. 4, in the intake manifold 23, four CNG injectors 27 are provided in series at predetermined intervals corresponding to the four combustion chambers 16. Yes. Each of the CNG injectors 27 is connected to a CNG delivery pipe 51 having a base end portion disposed above the CNG injector 27, a tip end portion enters the intake manifold 23, and a CNG injection pipe 29 is connected to each CNG injection pipe 29. , Each tangential port 17a is extended.

  The cylinder head 12 is provided with four light oil injectors 33 arranged in series at predetermined intervals located above the center of each combustion chamber 16. Each light oil injector 33 has a base end portion connected to a common rail 52 disposed above the intake manifold 23 via a pipe (not shown), and a tip end portion facing the combustion chamber 16.

  In this case, the CNG delivery pipe 51 is located above the intake manifold 23 and is disposed on one side in the arrangement direction of the combustion chambers 16 on the connection side of the intake pipe 24. The common rail 52 is located above the intake manifold 23 and is disposed on the coupling side of the cylinder head 12. That is, the CNG delivery pipe 51 and the common rail 52 are arranged above the intake manifold 23 in the horizontal direction.

  As described above, in the internal combustion engine according to the second embodiment, the tangential port 17a and the helical port 17b having different shapes communicating with the combustion chamber 16 are formed, and CNG fuel can be injected into the tangential port 17a. 27 and a light oil injector 33 capable of injecting light oil fuel into the combustion chamber 16 are provided, and a CNG delivery pipe 51 and a common rail 52 are arranged above the intake manifold 23 in a horizontal direction.

  Therefore, by disposing the CNG fuel supply system and the light oil fuel supply system above the intake manifold 23, each fuel supply system can be efficiently arranged, and the apparatus can be made compact.

  FIG. 5 is a schematic plan view showing an internal combustion engine according to Embodiment 3 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the diesel engine according to the third embodiment, as shown in FIG. 5, each intake port 17 includes a tangential port 17a and a helical port 17b. An intake manifold 23 is fastened to the side surface of the cylinder head 12 on the intake port 17 side, and an intake pipe 24 is connected to the intake manifold 23.

  In the intake manifold 23, four CNG injectors 27 corresponding to the four combustion chambers 16 are provided in series at a predetermined interval. Each of the CNG injectors 27 is connected to a CNG delivery pipe 28 disposed on the upper end side of the CNG injector 27, enters the intake manifold 23 on the distal end side, and a CNG injection pipe 29 is connected to the distal end portion. Each CNG injection pipe 29 extends in the intake manifold 23 toward each intake port 17 of the cylinder head 12, and a tip portion is inserted into each helical port 17b.

  Therefore, CNG fuel of a predetermined pressure is maintained in the CNG delivery pipe 28. By operating each CNG injector 27, the CNG fuel can be injected to each helical port 17b via the CNG injection pipe 29. .

  Accordingly, each CNG injector 27 injects CNG fuel from the CNG injection pipe 29 to the helical port 17b in each intake port 17 at a predetermined timing. In this case, the fuel injection timing of the CNG injector 27 is set during the intake stroke from when the exhaust valve 20 is closed to when the intake valve 19 is closed.

  Then, the CNG fuel injected into the helical port 17b is taken into the combustion chamber 16 together with the air taken into the helical port 17b through the intake pipe 24 through the air cleaner 25. At this time, the mixture of CNG fuel and air supplied to the combustion chamber 16 through the helical port 17b becomes a strong partial swirl flow. Note that the air introduced from the intake pipe 24 through the tangential port 17a into the combustion chamber 16 becomes a large swirl flow in the cylinder.

  On the other hand, each light oil injector 33 injects light oil fuel into each combustion chamber 16 at a predetermined timing. In this case, the light oil fuel is injected toward the cavity 14a of the piston 14, and is collected at the center thereof. Thereafter, when the inside of the combustion chamber 16 reaches a predetermined pressure, a mixture of CNG fuel and air is ignited with the light oil fuel as a base point. At this time, the swirl flow composed of the mixture of CNG fuel and air in the combustion chamber 16 activates the intake air flow and is easily ignited at the center of the combustion chamber 16 by the light oil fuel injected into the combustion chamber 16. An air-fuel mixture is formed, and stratified combustion of the air-fuel mixture is enabled, and ultra lean combustion is realized.

  Thus, in the internal combustion engine of the third embodiment, the tangential port 17a and the helical port 17b having different shapes communicating with the combustion chamber 16 are formed, and the CNG injector 27 capable of injecting CNG fuel, and the light oil fuel The CNG injector 27 injects CNG fuel into the helical port 17 b, and the light oil injector 33 injects light oil fuel into the combustion chamber 16.

  Therefore, by injecting the CNG fuel into the helical port 17b, the air and the CNG fuel are introduced into the combustion chamber 16 as a strong partial swirl flow, and the air and the CNG fuel are properly mixed. As a result, a good air-fuel mixture can be generated, and in particular, good stratified combustion can be realized and the combustibility can be improved during low-load operation of the engine.

  FIG. 6 is a schematic plan view showing an internal combustion engine according to Embodiment 4 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the diesel engine of the fourth embodiment, as shown in FIG. 6, each intake port 17 includes a tangential port 17a and a helical port 17b. An intake manifold 23 is fastened to the side surface of the cylinder head 12 on the intake port 17 side, and an intake pipe 24 is connected to the intake manifold 23.

  In the intake manifold 23, four CNG injectors 27 corresponding to the four combustion chambers 16 are provided in series at a predetermined interval. Each of the CNG injectors 27 is connected to a CNG delivery pipe 28 having a base end portion disposed above the CNG injector 27, a distal end portion enters the intake manifold 23, and a CNG injection pipe 61 is connected to the distal end portion. Each CNG injection pipe 61 extends in the intake manifold 23 toward each intake port 17 of the cylinder head 12 and has a tip portion facing each tangential port 17a or each helical port 17b.

  And the CNG injection pipe 61 connected with each CNG injector 27 can change the injection position between the tangential port 17a and the helical port 17b. That is, each CNG injection pipe 61 is configured by a soft member, and a connecting portion 62 is provided on the tip side, and each connecting portion 62 is connected by a connecting rod 63 along the arrangement direction of the CNG injectors 27. . And the diaphragm actuator 64 as an injection position change means is connected with the edge part of this connection rod 63, and this diaphragm actuator 64 can be controlled according to the driving | running state of a diesel engine by ECU.

  Therefore, when the ECU actuates the diaphragm actuator 64, each CNG injection pipe 61 is moved via the connecting rod 63, and the injection port provided at the tip portion is positioned opposite the tangential port 17a and the helical port. It can move between positions facing 17b.

  Therefore, when the diesel engine is in the high load operation region, the ECU operates the diaphragm actuator 64 and moves the injection port of each CNG injection pipe 61 to a position facing the tangential port 17a. Here, each CNG injector 27 injects CNG fuel from the CNG injection pipe 61 to the tangential port 17a in each intake port 17 at a predetermined timing.

  Then, the CNG fuel injected into the tangential port 17a is supplied into the combustion chamber 16 together with air. At this time, the mixture of CNG fuel and air supplied to the combustion chamber 16 through the tangential port 17a is: Large swirl flow in the cylinder. On the other hand, each light oil injector 33 injects light oil fuel into each combustion chamber 16 at a predetermined timing. In this case, the light oil fuel is injected toward the cavity 14a of the piston 14 and collected at the center thereof, and the mixture of CNG fuel and air is ignited with this light oil fuel as a base point, and at this ignition timing, A homogeneous air-fuel mixture is generated by the turbulence of the air flow generated by the increase in the swirl flow, the combustion speed is increased, and good homogeneous combustion is realized.

  On the other hand, when the diesel engine is in the low load operation region, the ECU operates the diaphragm actuator 64 and moves the injection port of each CNG injection pipe 61 to a position facing the helical port 17b. Here, each CNG injector 27 injects CNG fuel from the CNG injection pipe 61 to the helical port 17 b in each intake port 17 at a predetermined timing.

  Then, the CNG fuel injected into the helical port 17b is supplied into the combustion chamber 16 together with air. At this time, the mixture of CNG fuel and air supplied to the combustion chamber 16 through the helical port 17b has a strong portion. It becomes a typical swirl style. On the other hand, each light oil injector 33 injects light oil fuel into each combustion chamber 16 at a predetermined timing. In this case, the light oil fuel is injected toward the cavity 14a of the piston 14 and collected at the center thereof, and the mixture of CNG fuel and air is ignited with this light oil fuel as a base point. At this time, the swirl flow composed of the mixture of CNG fuel and air in the combustion chamber 16 activates the intake air flow and is easily ignited at the center of the combustion chamber 16 by the light oil fuel injected into the combustion chamber 16. An air-fuel mixture is formed, and stratified combustion of the air-fuel mixture is enabled, and ultra lean combustion is realized.

  Thus, in the internal combustion engine of the fourth embodiment, the tangential port 17a and the helical port 17b having different shapes communicating with the combustion chamber 16 are formed, and the CNG injector 27 capable of injecting CNG fuel, and the light oil fuel Is provided, and the injection position of the CNG injector 27 by the diaphragm actuator 64 can be changed between the tangential port 17a and the helical port 17b.

  Therefore, CNG fuel can be selectively injected between the tangential port 17a and the helical port 17b, and CNG fuel can be injected into an appropriate intake port according to the operating state of the diesel engine, thereby improving combustibility. Can be made.

  In the internal combustion engine of the fourth embodiment, the ECU injects CNG fuel into the tangential port 17a in the high load operation state according to the operation state of the diesel engine, and in the low load operation state, the ECU injects the CNG fuel into the helical port 17b. I try to spray. Therefore, good homogeneous combustion can be realized in high-load operation of a diesel engine, and good stratified combustion can be realized in low-load operation of a diesel engine. Can be improved.

  In each of the above-described embodiments, the tangential port 17a and the helical port 17b are provided as a plurality of intake ports having different shapes in the intake port 17. However, the present invention is not limited to this combination. It may be combined with a port. That is, as a plurality of intake ports of different shapes, a tangential port and a straight port may be provided, a helical port and a straight port may be provided, and further, three ports of a tangential port, a helical port and a straight port are provided. May be.

  As described above, the internal combustion engine according to the present invention is good by providing a plurality of intake ports having different shapes and allowing gaseous fuel to be injected into some of the plurality of intake ports by the gaseous fuel injection valve. Therefore, the present invention is useful for any type of internal combustion engine.

16 Combustion chamber (cylinder)
17 Intake port 17a Tangential port 17b Helical port 18 Exhaust port 27 CNG injector (gaseous fuel injection valve)
28,51 CNG delivery pipe 29 CNG injection pipe 32 Pressure regulator 33 Light oil injector (liquid fuel injection valve)
34, 52 Common rail 37 High pressure pump 41 Electronic control unit (ECU)
64 Diaphragm actuator (injection position changing means)

Claims (6)

A cylinder formed by an internal combustion engine body and a piston;
A plurality of intake ports having different shapes communicating with the cylinder;
An intake valve capable of opening and closing the intake port;
An exhaust port communicating with the cylinder;
An exhaust valve capable of opening and closing the exhaust port;
A gaseous fuel injection valve capable of injecting gaseous fuel into the intake port;
A liquid fuel injection valve capable of injecting liquid fuel into the cylinder;
An internal combustion engine comprising:
The gaseous fuel injection valve injects gaseous fuel into a part of the plurality of intake ports;
An internal combustion engine characterized by that.   2. The internal combustion engine according to claim 1, wherein the plurality of intake ports include at least two types of ports of a tangential port, a helical port, and a straight port.   The internal combustion engine according to claim 2, wherein the plurality of intake ports are a tangential port and a helical port, and the gaseous fuel injection valve injects gaseous fuel into the tangential port.   There are a plurality of cylinders, the same number of the gaseous fuel injection valves are provided for each cylinder, an intake pipe and the plurality of intake ports are communicated by an intake manifold, and the gaseous fuel injection valves are attached to the intake manifold. The internal combustion engine according to any one of claims 1 to 3, wherein the internal combustion engine extends from the injection port toward a part of the plurality of intake ports.   5. The internal combustion engine according to claim 1, further comprising an injection position changing unit capable of changing an injection position of the gaseous fuel injection valve among the plurality of intake ports. 6.   6. The internal combustion engine according to claim 5, further comprising control means for controlling the injection position changing means in accordance with an operating state of the internal combustion engine.

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