JP2010024994A - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine increasing engine torque and increasing fuel efficiency. <P>SOLUTION: This engine includes: two intake valves 34a, 34b; two fuel injection valves 45a, 45b; an intake valve drive device 40 driving the intake valves 34a, 34b; an intake valve drive control part 102 controlling the intake valve drive device 40; and a fuel injection control part 101 controlling fuel injection action by the fuel injection valves 45a, 45b. When the intake valve drive control part 102 closes one intake valve 34a and opens and closes the other intake valve 34b, the fuel injection control part 101 stops fuel injection from one fuel injection valve 45a on one intake valve 34a side, and executes fuel injection from the other fuel injection valve 45b on the other intake valve 34b side during a close period of the other intake valve 34b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a port injection type internal combustion engine, and more particularly, to a twin injector type internal combustion engine.

  Conventionally, an intake air of an engine provided with two intake valves provided for each cylinder, two intake ports corresponding thereto, and two fuel injection valves mounted on each of the two intake ports An apparatus is known (see, for example, Patent Document 1). In the intake device of this engine, the two intake valves are alternately opened every predetermined time, and at this time, the intake valve that performs the valve opening operation to prevent fuel accumulation in the other intake port Fuel is injected only from the fuel injection valve on the side.

JP 2001-159322 A

  By the way, according to the conventional engine intake device, fuel is injected from the fuel injection valve on the intake valve side that performs the valve opening operation. However, the valve opening timing of the intake valve and the fuel injection timing of the fuel injection valve are disclosed. It has not been. That is, when one intake valve is closed and the other intake valve is opened, that is, when the two intake valves are opened alternately every predetermined time, the fuel injection timing by the fuel injection valve In this case, fuel and air cannot be sufficiently introduced into the cylinder, and the engine torque obtained by combustion of the air-fuel mixture may be reduced.

  Accordingly, an object of the present invention is to provide an internal combustion engine that can improve engine torque and fuel efficiency.

  The internal combustion engine of the present invention includes a combustion chamber, two intake passages communicating with the combustion chamber, two intake valves that can open and close each intake passage, and two fuel injections that can inject fuel toward each intake passage. A valve, an intake valve driving means capable of fully opening and closing each intake valve between an open position and a closed position, and stopping at least one intake valve at the closed position; and an intake valve capable of controlling the intake valve drive means Drive control means and fuel injection control means capable of controlling the fuel injection operation by each fuel injection valve, and the intake valve drive control means stops one intake valve at the closed position while the other intake valve When the full opening / closing operation is performed, the fuel injection control means stops the fuel injection from one fuel injection valve on the one intake valve side and the fuel injection from the other fuel injection valve on the other intake valve side. During intake valve opening period Characterized in that row.

  In this case, the intake valve drive control means controls the intake valve drive means based on the operating region of the internal combustion engine, and the operating region can drive the internal combustion engine with the amount of air drawn from the other intake valve. When in the operation region, one intake valve is stopped at the closed position, while the other intake valve is fully opened and closed, and the fuel injection control means performs fuel injection from one fuel injection valve on one intake valve side. It is preferable that the fuel injection from the other fuel injection valve on the other intake valve side is performed during the valve opening period of the other intake valve while stopping.

  Further, in this case, the intake valve drive control means has a second operation region in which the operation region is a high load region as compared with the first operation region and the internal combustion engine can be driven by the amount of air drawn from the two intake valves. In this case, it is preferable that the two intake valves are fully opened and closed, and the fuel injection control means executes fuel injection from the two fuel injection valves.

  Further, in this case, the intake valve driving means is configured to be capable of half-opening / closing the at least one intake valve between the half-open position and the closed position. When it becomes the third operation region between the operation region and the second operation region, it is preferable that one intake valve is half-opened / closed and the other intake valve is fully opened / closed.

  Further, in this case, when the fuel injection control means executes fuel injection from the two fuel injection valves in the third operation region, the fuel injection control means has one fuel injection valve on the side of one intake valve that performs a half-opening / closing operation. It is preferable that the fuel injection from is performed during the closing period of one of the intake valves.

  Also, in this case, the fuel injection amount injected from one fuel injection valve on the side of one intake valve that performs a half-opening / closing operation is the fuel injection amount injected from the other fuel injection valve on the side of the other intake valve that performs a full opening / closing operation. It is preferable that the amount is smaller than the amount.

  In these cases, a throttle valve capable of adjusting the amount of intake air taken into the combustion chamber and throttle control means capable of controlling the throttle opening of the throttle valve are further provided, and the throttle control means includes two intake valves. It is preferable to increase the throttle opening when the third operating region in which the opening / closing operation is performed shifts to the first operating region in which one intake valve stops at the closed position and the other intake valve fully opens / closes. .

  The internal combustion engine according to the present invention performs fuel injection from the other fuel injection valve during the valve opening period of the other intake valve that is fully opened and closed when one intake valve is stopped at or near the closed position. As a result, the temperature of the sucked air can be lowered by the latent heat of vaporization of the fuel, and the charging efficiency of the air-fuel mixture can be improved. As a result, even when one intake valve is stopped at the closed position, the air-fuel mixture can be satisfactorily filled from the other intake valve, so that the engine torque obtained by the combustion of the air-fuel mixture can be improved. . In addition, since the injected fuel is introduced into the combustion chamber along with the airflow of the air that is sucked in, the adhesion of fuel around the intake port can be suppressed. Thereby, since almost all the injected fuel can be introduced into the combustion chamber, there is an effect that fuel efficiency can be improved.

  Hereinafter, an internal combustion engine according to the present invention will be described with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  Here, FIG. 1 is a schematic cross-sectional view showing the configuration of the port injection type engine according to this embodiment, and FIG. 2 shows the periphery of the combustion chamber of the port injection type engine according to this embodiment. It is a fragmentary sectional view. FIG. 3 is a top view of the intake-side communication port and the exhaust-side communication port as viewed from above the combustion chamber, and FIG. 4 is an explanatory diagram schematically showing an operation control map. Further, FIG. 5 is a diagram for explaining the relationship between the lift amount of the intake valve and the fuel injection amount from the fuel injection valve in each operation region, and FIG. 6 is a diagram when the throttle of the engine according to the present embodiment is fully opened. FIG. 7 is a time chart showing the combustion operation of the engine driven at high speed when the throttle of the engine according to this embodiment is fully opened. is there. FIG. 8 is a time chart showing the combustion operation of the engine driven at low / medium speed when the throttle of the engine according to the modification is fully opened, and FIG. 9 is when the throttle of the engine according to the modification is fully opened. 3 is a time chart showing the combustion operation of an engine driven at high speed.

  First, an internal combustion engine (hereinafter abbreviated as an engine) according to this embodiment will be described with reference to FIGS. 1 to 3. The engine 1 is a port injection engine and is controlled by the ECU 2.

  The engine 1 includes a crankcase 10 from the bottom, a cylinder block 11 provided at the top of the crankcase 10, and a cylinder head 12 provided at the top of the cylinder block 11 via a head gasket (not shown). Is formed. A plurality of pistons 13 are accommodated in the upper interior of the cylinder block 11 in accordance with the number of cylinders (one in the figure) so as to be reciprocally movable. The crankshaft 14 is accommodated. Each piston 13 and crankshaft 14 are connected by a connecting rod 15, and the reciprocating motion of each piston 13 is transmitted to the crankshaft 14. A plurality of pent roof type combustion chambers 16 are formed by the cylinder block 11, the cylinder head 12, and the piston 13 according to the number of cylinders.

  The crankcase 10 is provided with a crank angle sensor 20 that detects the rotation angle of the crankshaft 14. The crank angle sensor 20 is connected to the ECU 2. The ECU 2 performs an ignition operation of a spark plug 44 described later and a fuel injection operation of two fuel injection valves 45a and 45b described later based on the detection result of the crank angle sensor 20. These control the opening / closing operation of two intake valves 34a and 34b and two exhaust valves 35a and 35b, which will be described later.

  The cylinder block 11 is formed with a plurality of cylinder bores 24 penetrating in a cylindrical shape for accommodating a plurality of pistons 13 therein. The piston 13 is formed in a cylindrical shape so as to be fitted to the cylinder bore 24, and is supported in the cylinder bore 24 so as to be capable of reciprocating between a top dead center and a bottom dead center. Further, a piston cavity 25 is formed in the head surface of the piston 13 so as to be immersed.

  The cylinder head 12 has an intake port 30 communicating with the combustion chamber 16 and an exhaust port 31 disposed facing the intake port 30 and communicating with the combustion chamber 16 therein (see FIG. 3). The intake port 30 includes a collective intake passage 30a formed on the upstream side and two branched intake passages 30b (two intake passages) branched from the collective intake passage 30a and communicating with the combustion chamber 16, respectively. . The exhaust port 31 includes two branch exhaust passages 31b that are formed on the upstream side and communicate with the combustion chamber 16, respectively, and a collective exhaust passage 31a in which the two branch exhaust passages 31b merge.

  In addition, two intake valves 34a and 34b are respectively disposed in the two intake side communication ports 32 between the combustion chamber 16 and each branch intake passage 30b, and the combustion chamber 16 and each branch exhaust passage are provided. Two exhaust valves 35a and 35b are disposed in the two exhaust side communication ports 33 between 31b.

  As shown in FIG. 3, each intake side communication port 32 is formed in a circular shape when viewed from above, and each exhaust side communication port 33 is also formed in a circular shape when viewed from above, and each exhaust side communication port 33 is formed as an intake side communication port. The diameter is smaller than 32. The two intake side communication ports 32 are arranged adjacent to each other, and the two exhaust side communication ports 33 are also arranged adjacent to each other.

  Referring to FIG. 1 again, each of the intake valves 34a, 34b and each of the exhaust valves 35a, 35b is formed in a conical shape having an umbrella shape and is widened to the end, and each intake side communication port 32 and each exhaust side communication port 33 are formed. Is configured to be movable between an open position (lowering end position) where the air is released and a closed position (upward position) where the intake side communication ports 32 and the exhaust side communication ports 33 are closed. An intake valve driving device 40 that operates them at the base end portions of the two intake valves 34a and 34b, and an exhaust valve driving device 41 that operates them at the base end portions of the two exhaust valves 35a and 35b. Are respectively disposed.

  The intake valve driving device 40 is configured to fully open and close each intake valve 34a, 34b between the open position and the closed position, and to stop one intake valve 34a at the closed position. It is the structure provided with the valve stop mechanism. In addition, the intake valve drive device 40 can move one intake valve 34a to a half-open position, which is an intermediate position between the open position and the closed position, and one intake valve 34a is half-open. It is possible to perform a half-open / close operation between the position and the closed position. Thereby, the intake valve drive device 40 can halve the lift amount of one intake valve 34a.

  The half-open position is not limited to the intermediate position between the open position and the closed position, and may be in the vicinity of the intermediate position. Further, the closed position is not limited to the position where the lift amount of the intake valve becomes zero, but may be a position near zero, that is, between the half-open position and the closed position. That is, the intermediate position and the closed position may be within a range of deviation caused by errors such as control and dimensional tolerance. Although details will be described later, the intake valve driving device 40 is connected to the ECU 2, and the ECU 2 controls the intake valve driving device 40 to control the opening and closing operations of the intake valves 34 a and 34 b.

  The exhaust valve driving device 41 fully opens and closes the exhaust valves 35a and 35b between the open position and the closed position, and is connected to the ECU 2. The ECU 2 controls the exhaust valve driving device 41 to The opening / closing operation of the exhaust valves 35a and 35b is controlled.

  A spark plug 44 is disposed at the top of the combustion chamber 16 so that the tip portion protrudes. The spark plug 44 is connected to the ECU 2, and the ECU 2 controls the ignition operation based on the detection result by the crank angle sensor 20.

  In addition, two fuel injection valves 45a and 45b for injecting fuel toward the intake valves 34a and 34b are respectively disposed on the upper portions of the two branch intake passages 30b of the cylinder head 12 (see FIG. 3). ), So-called twin injector configuration. The two fuel injection valves 45 a and 45 b are connected to the ECU 2, and the ECU 2 controls the fuel injection operation based on the detection result by the crank angle sensor 20. Specifically, since each fuel injection valve 45a, 45b is disposed in each branch intake passage 30b in the vicinity of each intake valve 34a, 34b, the injection angle of each fuel injection valve 45a, 45b may be a wide angle. Thus, it is possible to suppress the fuel from adhering to the wall surface of each branch intake passage 30b. Further, since it is possible to perform fuel injection using the two fuel injection valves 45a and 45b, it is possible to reduce the fuel injection amount injected during one combustion cycle by half, thereby injecting fuel. It is possible to atomize the fuel.

  Although details will be described later, the ECU 2 controls the ignition control unit 100 that controls the ignition operation of the spark plug 44, the fuel injection control unit 101 that controls the fuel injection operations of the two fuel injection valves 45a and 45b, and 2 An intake valve drive control unit 102 that controls an intake valve drive device 40 that opens and closes the two intake valves 34a and 34b.

  Here, the combustion operation of the engine 1 during one combustion cycle will be described. In the combustion cycle, an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke are sequentially performed.

  In the intake stroke, the piston 13 starts moving from the top dead center to the bottom dead center, and at least one of the two intake valves 34a and 34b is moved forward to open the intake side communication port 32. Then, air is sucked into the combustion chamber 16 by the negative pressure of the combustion chamber 16 through the intake side communication port 32, and thereafter, the intake valves 34a and 34b moved forward are moved backward to close the intake side communication port 32. To do. At this time, the ECU 2 starts fuel injection from at least one of the two fuel injection valves 45a and 45b, and forms an air-fuel mixture by mixing the injected fuel and the sucked air.

  In the compression stroke, the piston 13 moves from the bottom dead center to the top dead center. When the piston 13 moves to the top dead center, the air-fuel mixture is compressed along with this movement. When the piston 13 reaches near the top dead center, the ECU 2 sparks the spark plug 44 and ignites the air-fuel mixture. Note that the fuel injection by the two fuel injection valves 45a and 45b ends before the spark plug 44 is discharged.

  In the expansion stroke, the air-fuel mixture expands (explodes) by combustion of the air-fuel mixture by ignition, and moves the piston 13 from the top dead center toward the bottom dead center.

  In the exhaust stroke, the piston 13 that has reached the bottom dead center moves again toward the top dead center due to inertia. At this time, the two exhaust valves 35a and 35b are moved forward to open the exhaust side communication port 33, and the exhaust gas after combustion is discharged from the exhaust side communication port 33 as the piston 13 moves to the top dead center. Let After the exhaust gas is discharged, the exhaust valves 35a and 35b are moved backward to close the exhaust side communication port 33.

  By repeating the above combustion cycle, each piston 13 is reciprocated, and this power is transmitted to the crankshaft 14 via the connecting rod 15, whereby the engine 1 can obtain a driving force.

  By the way, the combustion operation (operation) of the engine 1 is controlled based on the operation region of the engine 1, and specifically, the opening / closing operation of the two intake valves 34a and 34b is made variable or the two fuel injection valves are changed. The fuel injection operation of 45a and 45b is varied, or the ignition operation of the spark plug 44 is varied. Hereinafter, the operation control of the engine 1 will be specifically described.

  First, prior to the description of the operation control of the engine 1, the ECU 2 will be described. As described above, the ECU 2 includes the ignition control unit 100 that controls the ignition operation of the spark plug 44, the fuel injection control unit 101 that controls the fuel injection operation of the two fuel injection valves 45a and 45b, and the intake valve drive device 40. And an intake valve drive control unit 102 for controlling. The ECU 2 is connected to an air flow sensor 105 for detecting the amount of intake air taken into the engine 1 and a throttle opening sensor 106 for detecting the throttle opening of a throttle valve (not shown). A throttle control unit 103 that controls the throttle valve is provided. Further, the ECU 2 stores an operation control map M for controlling the operation of the engine 1 based on the engine speed and the engine torque.

  As shown in FIG. 4, the operation control map M has an engine rotation speed on the horizontal axis and an engine torque on the vertical axis. The operation control map M has three operation regions from a low rotation / low torque region to a high rotation / high torque region. Is set. The three operation regions are a one-valve stop operation region E1 (first operation region), a partial lift operation region E2 (third operation region), and a full lift operation region E3 (second operation region).

  The one-valve stop operation region E1 is set from the low rotation / low torque region to the medium rotation / medium torque region, and the engine 1 is sufficiently operated with the intake air amount sucked through the other intake valve 34b. It is a possible operating area.

  The full lift operation region E3 is set to a high rotation / high torque region, and is a region where the engine 1 can be operated with the intake air amount sucked from the two intake valves 34a and 34b. That is, the full lift operation region E3 is an operation region in which the engine 1 can be operated by sucking air from the two intake valves 34a and 34b.

  The partial lift operation region E2 is set in a region between the one-valve stop operation region E1 and the full lift operation region E3, and the intake air amount sucked through the other intake valve 34b and the two intake valves 34a, This is an operating region in which the engine 1 can be operated with an intake air amount between the intake air amount sucked through 34b.

  The intake valve drive control unit 102 controls the opening / closing operation of the two intake valves 34a and 34b, that is, the opening / closing timing and the lift amount via the intake valve driving device 40 based on the operation control map M. Specifically, as shown in the table of FIG. 5, when the engine 1 is driven in the one-valve stop operation region E1, the intake valve drive control unit 102 stops one intake valve 34a at the closed position. The other intake valve 34b is fully opened and closed between the open position and the closed position. That is, the intake valve drive control unit 102 sets the lift amount of one intake valve 34a to zero. In addition, when the engine 1 is driven in the partial lift operation region E2, the intake valve drive control unit 102 causes one intake valve 34a to perform a half-open / close operation between the closed position and the half-open position, and the other The intake valve 34b is fully opened and closed. That is, the intake valve drive control unit 102 sets the lift amount of one intake valve 34a as the partial lift amount (half lift amount). Further, the intake valve drive control unit 102 fully opens and closes the two intake valves 34a and 34b when the engine 1 is driven in the full lift operation region E3. That is, the intake valve drive control unit 102 sets the lift amounts of the two intake valves 34a and 34b as the full lift amount.

  The fuel injection control unit 101 controls the fuel injection operations of the two fuel injection valves 45a and 45b, that is, the fuel injection timing and the fuel injection amount, based on the operation control map M described above. Specifically, as shown in the table of FIG. 5, when the engine 1 is driven in the one-valve stop operation region E1, the fuel injection control unit 101 has one intake valve 34a side stopped at the closed position. The fuel injection from the fuel injection valve 45a is stopped, and the fuel injection from the other fuel injection valve 45b on the side of the other intake valve 34b that performs the full opening / closing operation is executed for the entire amount. At this time, the fuel injection control unit 101 executes fuel injection from the other fuel injection valve 45b during the opening period of the other intake valve 34b (intake synchronous injection). Fuel injection from the fuel injection valve 45b is executed immediately after the opening of the other intake valve 34b. Thereby, the fuel injected from the other fuel injection valve 45b is introduced on the air sucked into the combustion chamber 16 immediately after the other intake valve 34b is opened. The fuel introduced into the combustion chamber 16 is vaporized, so that the temperature of the air sucked into the combustion chamber 16 is lowered, thereby improving the charging efficiency of the air-fuel mixture.

  In addition, when the engine 1 is driven in the partial lift operation region E2, the fuel injection control unit 101 stops fuel injection from one fuel injection valve 45a on the side of one intake valve 34a that performs a half-opening / closing operation. Then, the fuel injection from the other fuel injection valve 45b on the side of the other intake valve 34b that performs the full opening / closing operation is executed for the entire amount. At this time, the fuel injection control unit 101 executes fuel injection from the other fuel injection valve 45b during the opening period of the other intake valve 34b.

  When the operating region of the engine 1 shifts from the partial lift operating region E2 to the full lift operating region E3 while driving at high speed, the fuel injection amount required to drive the engine 1 is injected from the other fuel injection valve 45b. Since it exceeds the maximum possible fuel injection amount, the fuel injection control unit 101 restarts the fuel injection from the one fuel injection valve 45a. At this time, the fuel injection control unit 101 performs the fuel injection from the resumed one fuel injection valve 45a during the closing period of the one intake valve 34a (intake asynchronous injection). As a result, the fuel injected from the one fuel injection valve 45a is vaporized in the one branch intake passage 30b, and the vaporized fuel flows into the combustion chamber 16 when the one intake valve 34a is opened. The mixture formation in 16 can be made homogeneous. In addition, when fuel is injected from the two fuel injection valves 45a and 45b, the total amount of the fuel injection amount to be injected is reduced by half and the fuel is injected.

  Further, the fuel injection control unit 101 executes fuel injection from the two fuel injection valves 45a and 45b when the engine 1 is driven in the full lift operation region E3. At this time, the fuel injection control unit 101 executes fuel injection from the two fuel injection valves 45a and 45b while the two intake valves 34a and 34b are open. In this case as well, since the fuel is injected from the two fuel injection valves 45a and 45b, the total amount of the fuel injection to be injected is reduced by half and the fuel is injected.

  The throttle controller 103 adjusts the amount of intake air flowing into the combustion chamber 16 by controlling the throttle opening / closing operation of the throttle valve as described above. For example, when the operation region of the engine 1 shifts from the full lift operation region E3 to the one-valve stop operation region E1, that is, when the number of intake valves 34a and 34b that perform full opening / closing operations is reduced from two to one, the throttle control unit 103 increases the throttle opening by the amount of one intake valve 34a stopped at the closed position. Specifically, when shifting from the full lift operation region E3 to the one-valve stop operation region E1, the throttle control unit 103 sets the throttle opening to the closed side. For this reason, the intake port 30 has a negative pressure and the intake resistance increases. At this time, the intake valve drive control unit 102 stops one intake valve 34a and fully opens / closes the other intake valve 34b, and the throttle control unit 103 increases the throttle opening. Thereby, the negative pressure in the intake port 30 is returned to the atmospheric pressure side, whereby the intake resistance is reduced, and the load applied to the reciprocating operation of the piston 13, that is, the pumping loss can be reduced.

  Here, a series of combustion operations of the engine 1 controlled based on the operation control map M will be described with reference to FIGS. 6 and 7. FIG. 6 is a time chart showing the combustion operation of the engine driven at low / medium speed when the throttle is fully opened, the horizontal axis is time (Time), and the vertical axis is the accelerator opening degree. The lift amounts of the two intake valves 34a and 34b, the intake air amounts from the two intake valves 34a and 34b, the fuel injection amounts of the two fuel injection valves 45a and 45b, and the ignition timing of the spark plug 44 are obtained.

  First, when the accelerator operation is performed so that the predetermined accelerator opening A1 with a small opening is changed to the predetermined accelerator opening B1 with a large opening, the operation region of the engine 1 is from the one-valve stop operation region E1. The process proceeds to the full lift operation region E3 via the partial lift operation region E2. That is, the operation region of the engine 1 during operation at the accelerator opening A1 is the one-valve stop operation region E1. Further, the operation region of the engine 1 at the time of transition from the accelerator opening A1 to the accelerator opening B1 is a partial lift operation region E2. And the driving | running | working area | region of the engine 1 at the time of the driving | operation with accelerator opening B1 turns into the full lift driving | running area E3.

  The opening / closing operation of the two intake valves 34a, 34b at this time will be described. In the one-valve stop operation region E1, one of the two intake valves 34a and 34b is stopped at the closed position and the other is fully opened and closed, so that the lift amount of one intake valve 34a becomes zero and the other intake valve The lift amount of the valve 34b is the full lift amount. In the partial lift operation region E2, the two intake valves 34a and 34b are half opened / closed and the other is fully opened / closed. Therefore, the lift amount of one intake valve 34a is half of the full lift amount, that is, The lift amount of the other intake valve 34b is the full lift amount. In the full lift operation region E3, since the two intake valves 34a and 34b are fully opened and closed, the lift amount of the two intake valves 34a and 34b is the full lift amount.

  In addition, the amount of intake air from the two intake valves 34a and 34b at this time will be described. In the one-valve stop operation region E1, since only the other intake valve 34b of the two intake valves 34a and 34b is fully opened and closed, the intake air amount sucked into the combustion chamber 16 is equal to a predetermined intake air amount. It has become. In the partial lift operation region E2, one of the two intake valves 34a and 34b performs a half open / close operation and the other performs a full open / close operation. Therefore, the intake air amount sucked into the combustion chamber 16 is equal to the intake valve 34a. Increases by half-opening and closing. The reason why the intake air amount increases slightly after the one intake valve 34a is opened and closed halfway is that the air flow sensor 105 for detecting the intake air amount is installed apart from the intake valves 34a and 34b. This is due to detection delay due to In the full lift operation region E3, since the two intake valves 34a and 34b are both fully opened and closed, the intake air amount sucked into the combustion chamber 16 is changed from the half open / close operation of the one intake valve 34a. Increased by shifting to the opening / closing operation.

  Further, the fuel injection amounts from the two fuel injection valves 45a and 45b at this time will be described. In the one-valve stop operation region E1, the two fuel injection valves 45a and 45b perform fuel injection only from the other side. Therefore, the fuel injection amount introduced into the combustion chamber 16 is a predetermined amount corresponding to the intake air amount. This is the amount of fuel injection. Further, in the partial lift operation region E2, the two fuel injection valves 45a and 45b perform fuel injection only from the other side. At this time, the amount of intake air sucked into the combustion chamber 16 increases as compared with the amount of intake air in the one-valve stop operation region E1, so the fuel injection amount injected from the other fuel injection valve 45b also increases. In the full lift operation region E3, the two fuel injection valves 45a and 45b perform fuel injection from both. At this time, the amount of intake air sucked into the combustion chamber 16 increases as compared with the amount of intake air in the partial lift operation region E2, so that the fuel injection amounts injected from the two fuel injection valves 45a and 45b also increase. In this case, since the fuel is injected from the two fuel injection valves 45a and 45b, the fuel injection amount to be injected can be reduced by half.

  Finally, the ignition timing of the spark plug 44 in this case will be described. In the one-valve stop operation region E1, the spark plug 44 discharges with a predetermined crank angle as an ignition timing. Further, in the partial lift operation region E2, the spark plug 44 greatly retards the ignition timing immediately after the half opening / closing operation of the one intake valve 34a, and then gradually advances the retarded ignition timing. go. Then, in the full lift operation region E3, the ignition plug 44 greatly retards the ignition timing immediately after the full opening / closing operation of the one intake valve 34a, and then gradually advances the retarded ignition timing. Then, gradually retard the ignition timing again. As a result, when the intake air amount and the fuel injection amount are increased, the ignition timing is greatly retarded, so that a torque step due to a sudden increase in engine torque can be suppressed, and deterioration of drivability due to the torque step is suppressed. can do.

  Next, FIG. 7 is a time chart showing the combustion operation of the engine driven at a high speed when the engine throttle is fully opened, the horizontal axis is time (Time), and the vertical axis is the accelerator opening. The lift amount of the two intake valves 34a and 34b, the intake air amount from the two intake valves 34a and 34b, the fuel injection amount of the two fuel injection valves 45a and 45b, and the ignition timing of the spark plug 44. . Only parts different from the time chart shown in FIG. 6 will be described.

  If the throttle is fully opened during high-speed operation of the engine 1, a large amount of fuel injection is required as described above. In this case, since the required fuel injection amount exceeds the maximum fuel injection amount that can be injected from the other fuel injection valve 45b, it is necessary to inject fuel from one fuel injection valve 45a even within the partial lift operation region E2. There is. That is, in the partial lift operation region E2, the two fuel injection valves 45a and 45b perform fuel injection from both. At this time, as described above, the other fuel injection valve 45b disposed on the side of the other intake valve 34b that is fully opened and closed performs fuel injection while the other intake valve 34b is open. On the other hand, one fuel injection valve 45a disposed on the side of one intake valve 34a that performs a half-opening / closing operation is executed during the closing period of one intake valve 34a. As shown in FIG. 7, in the partial lift operation region E2, since the fuel is injected from the two fuel injection valves 45a and 45b, the fuel injection amount to be injected can be reduced by half.

  According to the above configuration, fuel is not injected from one fuel injection valve 45a, and fuel is injected from the other fuel injection valve 45b during the opening period of the other intake valve 34b that is fully opened and closed. In addition, the temperature of the air taken in can be lowered by the latent heat of vaporization of the fuel, and the volumetric efficiency of the air-fuel mixture can be improved. Thus, even when one intake valve 34a is in a stopped state at the closed position, the air-fuel mixture can be satisfactorily charged from the other intake valve 34b, so that the engine torque obtained by the combustion of the air-fuel mixture is improved. Can do. In addition, since the injected fuel is introduced into the combustion chamber 16 along the airflow of the air that is sucked in, the adhesion of fuel around the branch intake passage 30b can be suppressed. As a result, almost all of the injected fuel can be introduced into the combustion chamber 16, so that fuel efficiency can be improved.

  Further, in the one-valve stop operation region E1, one intake valve 34a is stopped at or near the closed position, and fuel injection from one fuel injection valve 45a disposed on the one intake valve 34a side is stopped. By doing so, it is possible to prevent fuel from accumulating around the one intake valve 34a. For this reason, when one of the intake valves 34a is opened, it is possible to prevent occurrence of a torque step due to the accumulated fuel flowing into the combustion chamber 16, that is, excessive supply of fuel.

  Furthermore, if fuel injection is performed during the opening period of one intake valve 34a that performs a half-opening / closing operation, a large amount of fuel adheres to one intake valve 34a. For this reason, in the partial lift operation region E2 in which one intake valve 34a performs a half-opening / closing operation, by stopping fuel injection from one fuel injection valve 45a on the one intake valve 34a side, It is possible to prevent the fuel from adhering.

  Further, in the partial lift operation region E2 in which one intake valve 34a performs a half-opening / closing operation, when fuel is injected from one fuel injection valve 45a on the one intake valve 34a side, one fuel injection valve 45a is one intake air. Fuel is injected when the valve 34a is closed. Thus, the injected fuel is vaporized in the branch intake passage 30b on the side of the one intake valve 34a, and the vaporized fuel is introduced into the combustion chamber 16 when the one intake valve 34a is opened. The air-fuel mixture formed in 16 can be in a homogeneous state.

  Further, the full lift operation region E3 in which the two intake valves 34a and 34b are fully opened / closed is shifted to the single valve stop operation region E1 in which one intake valve 34a is stopped at the closed position and the other intake valve 34b is fully opened / closed. In this case, the throttle opening of the throttle valve can be increased. Thereby, since the pressure in the intake port 30 can be increased, the intake resistance is reduced, and the load applied to the reciprocating operation of the piston 13, that is, the pumping loss can be reduced.

  In the present embodiment, the intake valve driving device 40 is configured by a one-valve stop mechanism. However, the present invention is not limited thereto, and as a modification, the intake valve driving device 40 may be configured by a variable valve mechanism. That is, the variable valve mechanism can open and close at least one intake valve 34a with a desired lift amount. According to this configuration, as shown in FIGS. 8 and 9, the lift amount of one intake valve 34a can be continuously varied from zero to the full lift amount.

  Here, with reference to FIGS. 8 and 9, the combustion operation of the engine 1 controlled based on the operation control map M in a modification in which the intake valve driving device 40 is configured by a variable valve mechanism will be described. FIG. 8 is a time chart showing the combustion operation of the engine driven at low / medium speed when the throttle is fully opened, the horizontal axis is time (Time), and the vertical axis is the accelerator opening degree. The lift amounts of the two intake valves 34a and 34b, the intake air amounts from the two intake valves 34a and 34b, the fuel injection amounts of the two fuel injection valves 45a and 45b, and the ignition timing of the spark plug 44 are obtained. Only different parts will be described in order to avoid duplicate descriptions.

  First, when the accelerator operation is performed so that the predetermined accelerator opening A1 with a small opening is changed to the predetermined accelerator opening B1 with a large opening, the operation region of the engine 1 is from the one-valve stop operation region E1. The process proceeds to the full lift operation region E3 via the partial lift operation region E2. That is, when the engine 1 is operated at the accelerator opening A1, the operation region of the engine 1 is the one-valve stop operation region E1. Further, the operating region of the engine 1 when the accelerator opening A1 is shifted to the accelerator opening B1 is a partial lift operation region E2. When the engine 1 is operated at the accelerator opening B1, the operation region of the engine 1 is a full lift operation region E3.

  The opening / closing operation of the two intake valves 34a, 34b at this time will be described. In the one-valve stop operation region E1, one of the two intake valves 34a and 34b is stopped at the closed position and the other is fully opened and closed, so that the lift amount of one intake valve 34a becomes zero and the other intake valve The lift amount of the valve 34b is the full lift amount. In the partial lift operation region E2, one of the two intake valves 34a and 34b is opened and closed while continuously increasing the lift amount from zero to the full lift amount, and the other is fully opened and closed. In the full lift operation region E3, the two intake valves 34a and 34b are fully opened / closed, so the lift amount of the two intake valves 34a and 34b is the full lift amount.

  In addition, the amount of intake air from the two intake valves 34a and 34b at this time will be described. In the one-valve stop operation region E1, since only the other intake valve 34b of the two intake valves 34a and 34b is fully opened and closed, the intake air amount sucked into the combustion chamber 16 is equal to a predetermined intake air amount. It has become. In the partial lift operation region E2, since the lift amount of one of the two intake valves 34a and 34b continuously increases and the other fully opens and closes, the intake air amount sucked into the combustion chamber 16 is one side. The lift amount of the intake valve 34a increases as the lift amount increases. That is, the intake air amount also increases continuously. In the full lift operation region E3, since the two intake valves 34a and 34b are both fully opened and closed, the amount of intake air sucked into the combustion chamber 16 is the amount that one intake valve 34a is fully opened and closed. ,To increase.

  Further, the fuel injection amounts from the two fuel injection valves 45a and 45b at this time will be described. In the one-valve stop operation region E1, the two fuel injection valves 45a and 45b perform fuel injection only from the other side. Therefore, the fuel injection amount introduced into the combustion chamber 16 is a predetermined amount corresponding to the intake air amount. This is the amount of fuel injection. Further, in the partial lift operation region E2, the two fuel injection valves 45a and 45b perform fuel injection only from the other side. At this time, since the intake air amount sucked into the combustion chamber 16 continuously increases from the intake air amount in the one-valve stop operation region E1, the fuel injection amount injected from the other fuel injection valve 45b also increases continuously. To do. In the full lift operation region E3, the two fuel injection valves 45a and 45b perform fuel injection from both. At this time, the intake air amount sucked into the combustion chamber 16 becomes the maximum intake air amount that has continuously increased in the partial lift operation region E2. In this case, since the fuel is injected from the two fuel injection valves 45a and 45b, the fuel injection amount to be injected can be reduced by half.

  Finally, the ignition timing of the spark plug 44 in this case will be described. In the one-valve stop operation region E1, the spark plug 44 discharges with a predetermined crank angle as an ignition timing. In the partial lift operation region E2, the spark plug 44 gradually advances the ignition timing. In the full lift operation region E3, the spark plug 44 gradually retards the ignition timing. That is, since the intake air amount and the fuel injection amount gradually increase, it is not necessary to retard the ignition timing greatly.

  Next, FIG. 9 is a time chart showing the combustion operation of the engine driven at a high speed when the engine throttle is fully opened, the horizontal axis is time (Time), and the vertical axis is the accelerator opening. The lift amount of the two intake valves 34a and 34b, the intake air amount from the two intake valves 34a and 34b, the fuel injection amount of the two fuel injection valves 45a and 45b, and the ignition timing of the spark plug 44. . Only parts different from the time chart shown in FIG. 8 will be described.

  If the throttle is fully opened during high-speed operation of the engine 1, a large amount of fuel injection is required as described above. In this case, since the required fuel injection amount exceeds the maximum fuel injection amount that can be injected from the other fuel injection valve 45b, it is necessary to inject fuel from one fuel injection valve 45a even within the partial lift operation region E2. There is. That is, in the partial lift operation region E2, the two fuel injection valves 45a and 45b perform fuel injection from both. At this time, as described above, the other fuel injection valve 45b disposed on the side of the other intake valve 34b that is fully opened and closed performs fuel injection while the other intake valve 34b is open. On the other hand, one fuel injection valve 45a disposed on the side of one intake valve 34a where the lift amount continuously increases is executed during the closing period of one intake valve 34a. In the partial lift operation region E2, when fuel injection is performed from the two fuel injection valves 45a and 45b, the fuel injection amount from each fuel injection valve 45a and 45b is halved as shown in FIG.

  Even in the above configuration, fuel is not injected from one fuel injection valve 45a, and fuel is injected from the other fuel injection valve 45b during the opening period of the other intake valve 34b that is fully opened and closed. The temperature of the air taken in can be lowered by the latent heat of vaporization of the fuel, and the charging efficiency of the air-fuel mixture can be improved. Thus, even when one intake valve 34a is in a stopped state at the closed position, the air-fuel mixture can be satisfactorily charged from the other intake valve 34b, so that the engine torque obtained by the combustion of the air-fuel mixture is improved. Can do.

  In addition, in the partial lift operation region E2 at the time of high rotation operation of the engine 1 shown in FIGS. 7 and 9, the fuel injection amount injected from the two fuel injection valves 45a and 45b is halved. The fuel injection amount from one fuel injection valve 45a provided on the side of one intake valve 34a that performs the half-opening / closing operation is changed from the other fuel injection valve 45b provided on the side of the other intake valve 34b that performs the full opening / closing operation. The fuel injection amount may be a small amount compared to the fuel injection amount.

  As described above, the present invention is useful in a port injection type internal combustion engine, and is particularly suitable for a twin injector type internal combustion engine.

It is typical sectional drawing showing the composition of the port injection type engine concerning this example. It is a fragmentary sectional view showing the circumference of a combustion chamber of a port injection type engine concerning this example. FIG. 4 is a top view of an intake side communication port and an exhaust side communication port as viewed from above the combustion chamber. It is explanatory drawing which represented the driving | operation control map typically. It is a figure explaining the relationship between the lift amount of the intake valve and the fuel injection amount from the fuel injection valve in each operation region. 6 is a time chart showing a combustion operation of an engine driven at low / medium speed when the throttle of the engine according to the present embodiment is fully opened. 6 is a time chart showing a combustion operation of an engine driven at a high speed when the throttle of the engine according to the present embodiment is fully opened. 10 is a time chart showing a combustion operation of an engine driven at low / medium speed when the throttle according to a modification is fully opened. 7 is a time chart showing a combustion operation of an engine driven at a high speed when the throttle of the engine according to a modification is fully opened.

Explanation of symbols

1 Engine 2 ECU
DESCRIPTION OF SYMBOLS 10 Crankcase 11 Cylinder block 12 Cylinder head 13 Piston 14 Crankshaft 15 Connecting rod 16 Combustion chamber 20 Crank angle sensor 24 Cylinder bore 25 Piston cavity 30 Intake port 30a Collecting intake passage 30b Branching intake passage 31 Exhaust port 31a Collecting exhaust passage 31b Branching exhaust passage 32 Intake side communication port 33 Exhaust side communication port 34a, 34b Intake valve 35a, 35b Exhaust valve 40 Intake valve drive device 41 Exhaust valve drive device 44 Spark plug 45a, 45b Fuel injection valve 100 Ignition control unit 101 Fuel injection control unit 102 Intake Valve drive control unit 103 Throttle control unit 105 Air flow sensor 106 Throttle opening sensor M Operation control map E1 Single valve stop operation region E2 Partial lift operation region E3 Full lift Operating area

Claims (7)

A combustion chamber;
Two intake passages communicating with the combustion chamber;
Two intake valves that can freely open and close each intake passage;
Two fuel injection valves capable of injecting fuel toward the intake passages;
An intake valve driving means capable of fully opening and closing each of the intake valves between an open position and a closed position, and stopping at least one of the intake valves at the closed position;
Intake valve drive control means capable of controlling the intake valve drive means;
Fuel injection control means capable of controlling the fuel injection operation by each fuel injection valve,
When the intake valve drive control means stops the one intake valve at the closed position and fully opens and closes the other intake valve, the fuel injection control means The fuel injection from one fuel injection valve is stopped, and the fuel injection from the other fuel injection valve on the other intake valve side is executed during the opening period of the other intake valve. Internal combustion engine. The intake valve drive control means controls the intake valve drive means based on the operating region of the internal combustion engine, and the operating region can drive the internal combustion engine with the amount of air drawn from the other intake valve. When in one operating region, the one intake valve is stopped at the closed position, while the other intake valve is fully opened and closed,
The fuel injection control means stops fuel injection from the one fuel injection valve on the one intake valve side, and performs fuel injection from the other fuel injection valve on the other intake valve side to the other intake valve side. The internal combustion engine according to claim 1, wherein the internal combustion engine is executed during the opening period of the intake valve. The intake valve drive control means is a second operation region in which the operation region is a high load region as compared with the first operation region and the internal combustion engine can be driven by the amount of air sucked from the two intake valves. At one time, the two intake valves are fully opened and closed,
The internal combustion engine according to claim 2, wherein the fuel injection control means executes fuel injection from the two fuel injection valves. The intake valve driving means is configured to be capable of semi-opening and closing at least one of the intake valves between a semi-open position and the closed position,
The intake valve drive control means causes the one intake valve to perform a half-open / close operation when the operation region is a third operation region between the first operation region and the second operation region, and The internal combustion engine according to claim 3, wherein the intake valve is fully opened and closed.   In the third operating region, when the fuel injection control means executes fuel injection from the two fuel injection valves, the fuel injection control means performs the one fuel injection on the side of the one intake valve that performs a half-opening / closing operation. The internal combustion engine according to claim 4, wherein fuel injection from the valve is performed during a closing period of the one intake valve.   The fuel injection amount injected from the one fuel injection valve on the side of the one intake valve that performs the half-opening / closing operation is the fuel injection amount injected from the other fuel injection valve on the side of the other intake valve that performs the full opening / closing operation. 6. The internal combustion engine according to claim 5, wherein the amount is smaller than that of the engine. A throttle valve capable of adjusting the amount of intake air sucked into the combustion chamber;
Throttle control means capable of controlling the throttle opening of the throttle valve, and
From the third operating region in which the two intake valves perform an opening / closing operation, the throttle control means is configured to perform the first operation in which the one intake valve stops at the closed position and the other intake valve fully opens / closes. The internal combustion engine according to claim 5 or 6, wherein the throttle opening is increased when shifting to the operating region.

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