JP2004092429A - Engine with turbocharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve both efficient engine output performance improvement by a turbocharger and exhaust gas purification performance improvement. <P>SOLUTION: The exhaust from a first exhaust valve 7a reaches a turbine 25 through a first exhaust port 5a and a first exhaust passageway 22, then passes through a main catalyst 26, and is discharged. The exhaust from a second exhaust valve 7b is led to the middle of the first exhaust passageway 22 through a second exhaust port 5b, a second exhaust passageway 23, and a first catalyst 24, and reaches the turbine 25 through the first exhaust passageway 22. When an engine is cold, each first exhaust valve 7a is inactive and each second exhaust valve 7b is active except during high load and high rotation, and both the valves are active during high load and high rotation. After the engine warms up, both the valves are active during low load and low rotation and during high load and high rotation, and each first exhaust valve 7a is active and each second exhaust valve 7b is inactive in the other region. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an engine with a turbocharger having a plurality of exhaust valves and a plurality of cylinders capable of operating and deactivating these exhaust valves independently.
[0002]
[Prior art]
In recent years, an engine having a plurality of exhaust valves and a plurality of cylinders capable of independently operating and deactivating these exhaust valves has been put into practical use.
[0003]
For example, in Japanese Patent Application Laid-Open No. Hei 7-91237, first and second exhaust ports and first and second exhaust valves for individually opening and closing the first and second exhaust ports are provided for each cylinder, and the first exhaust port of each cylinder is provided with a first exhaust port. The branch pipe of the exhaust manifold is connected to the second exhaust port, the branch pipe of the second exhaust manifold is connected, the respective exhaust manifolds are connected to a common exhaust pipe, and the lower exhaust pipe is connected to the first exhaust manifold. There is disclosed an exhaust gas purifying apparatus for an engine in which an adsorption trapper for adsorbing HC at the time and a catalytic converter are interposed in an exhaust pipe.
[0004]
[Problems to be solved by the invention]
In the case where a turbocharger is provided in the above-described prior art engine, if a catalyst is provided upstream of the turbine, turbine efficiency is reduced due to exhaust resistance of the catalyst portion, and engine back pressure is increased, which causes a reduction in output. .
[0005]
Therefore, when a turbocharger is provided in the above-described engine, the turbocharger turbine is installed in order to achieve both efficient engine output performance improvement and exhaust gas purification performance improvement by the turbocharger. It is necessary to control the variable valve mechanism appropriately in accordance with the operating state of the engine by arranging it at an optimum position and taking into account the output characteristics of the turbocharger and the characteristics of the catalyst precisely.
[0006]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a turbocharger by arranging a turbine of a turbocharger at an optimum position and appropriately controlling a variable valve mechanism according to an engine operating state. It is an object of the present invention to provide an engine with a turbocharger, which can achieve both efficient improvement in engine output performance and improvement in exhaust gas purification performance.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, an engine with a turbocharger according to the present invention according to claim 1 has a first exhaust valve capable of controlling at least operation and non-operation, and operates independently of the first exhaust valve. A second exhaust valve having a controllable non-operation; a first exhaust port communicating with the first exhaust valve and a second exhaust port communicating with the second exhaust valve are formed independently; A first exhaust passage connected to the turbine inlet side of the turbocharger to collect and lead the exhaust from each of the first exhaust ports; A second exhaust passage connected to a middle portion of the first exhaust passage and collecting and discharging exhaust gas from each of the second exhaust ports. A first catalyst is provided in the middle of the second exhaust passage. A second catalyst downstream of the turbine of the turbocharger It is characterized by providing.
[0008]
According to a second aspect of the present invention, there is provided an engine with a turbocharger according to the present invention, wherein a first exhaust valve capable of controlling at least operation and non-operation, and operation and non-operation controlled independently of the first exhaust valve. A plurality of cylinders each having a freely movable second exhaust valve and having independently formed a first exhaust port communicating with the first exhaust valve and a second exhaust port communicating with the second exhaust valve. On the other hand, in an engine with a turbocharger in which a turbine of a turbocharger is divided into at least a first exhaust passage portion and a second exhaust passage portion having a smaller cross section than the first exhaust passage portion, A first exhaust passage connected to an inlet side of the first exhaust passage portion to collect and extract exhaust gas from each of the first exhaust ports, and connected to an inlet side of a second exhaust passage portion of the turbine; Exhaust from each of the second exhaust ports A second exhaust passage for collecting and leading out, a first catalyst interposed in the middle of the second exhaust passage, and a second catalyst provided downstream of a turbine of the turbocharger. It is characterized by.
[0009]
Further, the engine with a turbocharger according to the present invention according to claim 3 is the engine with turbocharger according to claim 1 or 2, wherein each of the first exhaust valves is closed when the engine is cold. And the second exhaust valve is operated.
[0010]
The engine with a turbocharger according to the present invention described in claim 4 is the engine with a turbocharger according to any one of claims 1 to 3, wherein the engine operates when the engine is cold. When a high-speed, high-load operation state is set in advance, each of the first exhaust valves and each of the second exhaust valves are operated.
[0011]
Further, according to a fifth aspect of the present invention, in the engine with a turbocharger according to any one of the first to fourth aspects, after the engine is warmed, each of the first and second turbochargers is replaced with the first one. And the second exhaust valve is closed and deactivated.
[0012]
The engine with a turbocharger according to the present invention according to claim 6 is the engine with a turbocharger according to any one of claims 1 to 5, wherein the engine operation is performed in advance after the engine is warmed up. When the set high-speed, high-load operation state is set, the first exhaust valve and the second exhaust valve are operated.
[0013]
Further, the engine with a turbocharger according to the present invention according to claim 7 is the engine with a turbocharger according to any one of claims 1 to 6, wherein the engine operation is previously performed after the engine is warmed up. When the set low-speed, low-load operation state is established, the first exhaust valve and the second exhaust valve are operated.
[0014]
The engine with a turbocharger according to the present invention described in claim 8 is the engine with a turbocharger according to any one of claims 1 to 7, wherein each first exhaust gas of each of the cylinders is provided. The ports are connected to the first exhaust passage after being merged.
[0015]
Further, according to a ninth aspect of the present invention, in the engine with a turbocharger according to any one of the first to eighth aspects, each second exhaust gas of each of the cylinders is provided. The ports are connected to the second exhaust passage after being merged.
[0016]
That is, in the engine with the turbocharger according to the first aspect, exhaust from the first exhaust valve of each cylinder reaches the turbine of the turbocharger via the first exhaust port and the first exhaust passage. I do. Then, the gas is discharged through the second catalyst through the turbine. On the other hand, the exhaust gas from the second exhaust valve of each cylinder is guided to the middle of the first exhaust passage via the second exhaust port, the second exhaust passage, and the first catalyst. And reaches the turbine of the turbocharger through the exhaust passage of the turbocharger. Then, the gas is discharged through the second catalyst through the turbine. In this way, the catalyst interposed upstream of the turbine is constituted only by the first catalyst, and is configured so that a decrease in turbine efficiency and an increase in engine back pressure are minimized.
[0017]
Also, in the engine with a turbocharger according to the second aspect, the exhaust gas from the first exhaust valve of each cylinder is supplied to the turbocharger turbine through the first exhaust port and the first exhaust passage. No. 1 exhaust passage. Then, the gas is discharged through the second catalyst through the first exhaust passage. On the other hand, the exhaust from the second exhaust valve of each cylinder is cross-sectioned from the first exhaust passage of the turbocharger turbine via the second exhaust port, the second exhaust passage, and the first catalyst. To the second exhaust passage portion having a smaller value. Then, the fuel is discharged through the second catalyst through the second exhaust passage. In this way, even in the turbocharged engine in which the turbine of the turbocharger is divided into at least the first exhaust passage portion and the second exhaust passage portion having a smaller cross section than the first exhaust passage portion, the turbine is provided upstream of the turbine. The interposed catalyst is constituted only by the first catalyst, and is constituted so that a decrease in turbine efficiency and an increase in engine back pressure are minimized.
[0018]
In the engine with a turbocharger according to claim 1 or 2 configured as described above, as described in claim 3, when the engine is cold, each first exhaust valve is closed and deactivated. By operating each of the second exhaust valves, the first catalyst is activated at an early stage so that the exhaust gas can be efficiently purified.
[0019]
Further, when the engine operation is in a preset high-speed, high-load operation state when the engine is cold, each first exhaust valve and each second exhaust valve are connected. By operating the exhaust valve, protection of the first catalyst in a high-speed, high-load operation state can be effectively performed.
[0020]
Further, as described in claim 5, after the engine is warmed up, the first exhaust valves are operated, and the second exhaust valves are closed and deactivated, so that the exhaust gas causes the first catalyst to operate. The gas is bypassed and supplied to the turbine, thereby improving the turbine efficiency and reducing the engine back pressure to generate high output. In addition, the exhaust blowdown pressure can be effectively used, and better supercharging characteristics can be obtained than at low rotation speeds, and traveling performance can be improved.
[0021]
Further, when the engine operation is set to a preset high-speed, high-load operation state after the engine is warmed up, each first exhaust valve and each second exhaust valve are provided. By operating the valve, the exhaust efficiency of the engine can be improved and the maximum output can be improved. In addition, the protection of the first catalyst in a high-speed, high-load operation state can be effectively performed. It is also possible to prevent a decrease in exhaust gas cleaning performance due to thermal deterioration of the catalyst.
[0022]
Further, when the engine operation is brought into a preset low-speed, low-load operation state after the engine is warmed up, each first exhaust valve and each second exhaust valve are set. By operating the valve, it is possible to improve the exhaust efficiency of the engine and improve the fuel efficiency, and also to improve the exhaust gas purification performance by the effects of the first catalyst and the second catalyst. Can be.
[0023]
In the engine with a turbocharger according to any one of claims 1 to 7, as described in claim 8, after the first exhaust ports of the cylinders are joined to each other, the first exhaust is performed. If the second exhaust port of each cylinder is connected to the second exhaust port after being connected to the passage, or the second exhaust port of each cylinder is joined, as described in claim 9, the exhaust passage volume is reduced, Since the exhaust gas temperature can be raised, the first catalyst can be activated early.
[0024]
Embodiment
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIGS. 1 to 6 show a first embodiment of the present invention. FIG. 1 is an explanatory diagram of the overall configuration of a turbocharged engine, and FIG. 2 is an explanatory diagram of an exhaust passage connected to each exhaust port of each cylinder head. , FIG. 3 is a circuit configuration diagram of an electronic control system, FIG. 4 is a flowchart of exhaust valve operation control, FIG. 5 is a region characteristic diagram for setting operation and non-operation of an exhaust valve when the engine is cold, and FIG. FIG. 6 is a region characteristic diagram for setting the operation and non-operation of the exhaust valve in FIG.
[0025]
First, the overall configuration of a turbocharged engine to which the present invention is applied will be described with reference to FIG. In FIG. 1, reference numeral 1 denotes a turbocharged engine (hereinafter abbreviated as "engine"), and in this embodiment, a horizontally opposed four-cylinder gasoline engine. Cylinder heads 3 are respectively provided in both left and right banks of the cylinder block 2 of the engine 1 provided with two cylinders each, and each cylinder head 3 is formed with an intake port 4 and an exhaust port 5 communicating with each cylinder. .
[0026]
Here, each cylinder of the left bank or the right bank has a pair of intake valves 6 and a pair of exhaust valves 7, and the pair of intake valves 6 are connected to respective intake ports 4. ing.
[0027]
An intake manifold 8 communicates with the intake port 4, and a throttle body 10 communicates with an upstream gathering portion of the intake manifold 8 via an air chamber 9. An air cleaner 12 is mounted on an upstream side of the throttle body 10 via an intake pipe 11, and the air cleaner 12 is connected to an air intake chamber 13.
[0028]
A throttle valve 14 is provided on the throttle body 10, an intercooler 15 is interposed in an intake pipe 11 immediately upstream of the throttle body 10, and a resonator chamber 16 is provided downstream of the air cleaner 12 in the intake pipe 11. Is interposed.
[0029]
The resonator chamber 16 and the intake manifold 8 are connected by a bypass passage 17 that bypasses the upstream side and the downstream side of the throttle valve 14. The bypass passage 17 is connected to an idle speed control valve (idle A rotation speed control valve (ISC valve) 18 is interposed. Immediately downstream of the ISC valve 18, a check valve 20 that opens when the intake pressure is negative and closes when the intake pressure becomes positive when supercharged by the turbocharger 19 is interposed. Have been.
[0030]
Further, as shown in FIG. 2A, the first exhaust port 5a of the exhaust port 5 is communicated with the outer exhaust valve (first exhaust valve) 7a in each bank, and is adjacent in each bank. The second exhaust port 5b of the exhaust port 5 is connected to the exhaust valve (second exhaust valve) 7b.
[0031]
Further, the first exhaust valve 7a and the second exhaust valve 7b are independently provided to each other by a later-described electronic control unit (ECU) 60 to select a cam for operating a rocker arm of a valve operating mechanism by hydraulic pressure. A valve operation selection mechanism 21 is provided, which can be selected to be activated or deactivated while being closed.
[0032]
The first exhaust port 5a of the exhaust port 5 communicates with a first exhaust passage 22 whose inlet side is bifurcated, and the second exhaust port 5b of the exhaust port 5 has the same inlet side as the second exhaust port 5b. A second exhaust passage 23 branched to the crotch communicates with the crotch. A first catalyst 24 is interposed in the second exhaust passage 23, and a downstream end is connected to a middle part of the first exhaust passage 22.
[0033]
Thus, the first exhaust passage 22 to which the second exhaust passage 23 is connected is communicated with the inlet of the turbine 25 of the turbocharger 19, and the main catalyst (second catalyst) 26 is connected to the outlet of the turbine 25. And an exhaust pipe 28 connected to the muffler 27 is connected.
[0034]
In the turbocharger 19, a compressor 29 is provided downstream of the resonator chamber 16 of the intake pipe 11. Thus, in the turbocharger 19, the compressor 29 is rotationally driven by the exhaust energy introduced into the turbine 25, and sucks and pressurizes air to supercharge.
[0035]
A wastegate valve 30 is interposed at the inlet of the turbine housing of the turbocharger 19, and a wastegate valve operating actuator 31 is connected to the wastegate valve 30. The waste gate valve actuating actuator 31 is partitioned into two chambers by a diaphragm, one of which forms a pressure chamber communicating with the waste gate valve control duty solenoid valve 32, and the other biases the waste gate valve 30 in the closing direction. A spring chamber containing the spring is formed.
[0036]
The wastegate valve control duty solenoid valve 32 has a port communicating with the pressure chamber of the actuator 31 for operating the wastegate valve, a port communicating with the compressor downstream of the turbocharger 19, and a port communicating with the resonator chamber 16. The opening degree of the port communicating with the resonator chamber 16 is adjusted according to the duty ratio of the control signal output from the ECU 60, and the pressure on the resonator chamber 16 side and the pressure on the compressor downstream side are adjusted. The pressure is regulated and the control pressure is supplied to the pressure chamber of the wastegate valve actuating actuator 31, and the opening degree of the wastegate valve 30 is adjusted to control the supercharging pressure.
[0037]
On the other hand, an injector 33 is located immediately upstream of each intake port 4 of each cylinder of the intake manifold 8, and fuel in a fuel tank (not shown) is pressure-fed by a fuel pump (not shown), and is also supplied to the injector 33 by a pressure regulator (not shown). Is regulated to a predetermined pressure.
[0038]
Further, an ignition plug 34 whose tip is exposed to the combustion chamber is attached to each cylinder of the cylinder head 3, and an igniter 36 is connected to the ignition plug 34 via an ignition coil 35 provided for each cylinder. Have been.
[0039]
In the above description, an example is described in which the first exhaust port 5a and the second exhaust port 5b of the exhaust port 5 are connected to the first exhaust passage 22 and the second exhaust passage 23, each of which has a branched inlet. However, as shown in FIG. 2 (b), for example, adjacent second exhaust ports 5b are formed by merging in advance in the cylinder head 3, and a second exhaust passage 23 is formed in the merged port. You may make it connect. Also, if possible in a three-dimensional space, the first exhaust ports 5a are formed by merging in advance in the cylinder head 3, and the first exhaust passage 22 is connected to the merged ports. You may do it. By configuring the pipe in this manner, the volume of the exhaust passage can be reduced, and the exhaust temperature can be increased. Therefore, particularly when the first exhaust ports 5a are formed by merging the first exhaust ports 5a in the cylinder head 3 in advance. Thus, the first catalyst 24 can be activated early.
[0040]
Next, various sensors will be described. An absolute pressure sensor 38 is provided to select and detect the intake pipe pressure downstream of the throttle valve 14 (the intake pressure in the intake manifold 8) and the atmospheric pressure by an intake pipe pressure / atmospheric pressure switching solenoid valve 39. A knock sensor 40 is attached to the cylinder block 2, and a cooling water temperature sensor 42 faces a cooling water passage 41 that connects the left and right banks. Further, a throttle opening sensor 43 is connected to the throttle valve 14, and an intake air amount sensor 44 is provided immediately downstream of the air cleaner 12.
[0041]
Further, a crank rotor 46 is axially mounted on a crankshaft 45 of the engine 1, and a crank angle sensor 47 composed of an electromagnetic pickup or the like is provided around the outer periphery of the crank rotor 46. Further, a cylinder discriminating sensor 50 composed of an electromagnetic pickup or the like is provided opposite to a cam rotor 49 connected to the camshaft 48 in the valve operating mechanism.
[0042]
The crank angle sensor 47 and the cylinder discrimination sensor 50 detect protrusions formed at predetermined intervals on the crank rotor 46 and the cam rotor 49, respectively, with the operation of the engine, and output a crank pulse and a cylinder discrimination pulse. The ECU 60 calculates the engine speed from the crank pulse interval time (projection detection interval), calculates the ignition timing, the fuel injection timing, and the like, and further determines the cylinder discrimination from the input pattern of the crank pulse and the cylinder discrimination pulse. I do.
[0043]
Next, the configuration of the electronic control system will be described with reference to FIG. The ECU 60 mainly includes a microcomputer in which a CPU 61, a ROM 62, a RAM 63, a backup RAM 64, a counter / timer group 65, and an I / O interface 66 are connected via a bus line, and supplies a predetermined stabilized power to each unit. Peripheral circuits such as a constant voltage circuit 67, a drive circuit 68, and an A / D converter 69 are provided.
[0044]
The counter / timer group 65 includes a free-run counter, various counters such as a counter for counting the input of a cylinder determination sensor signal (cylinder determination pulse), a fuel injection timer, an ignition timer, and a periodic interrupt for generating a periodic interrupt. Timers and watchdog timers for monitoring system abnormalities are collectively referred to for convenience, and also include various software counters and timers.
[0045]
The constant voltage circuit 67 is connected to the battery 71 via a first relay contact of a power relay 70 having two relay contacts. The power relay 70 has one end of a relay coil grounded and the other end of the relay coil. Are connected to the drive circuit 68. A power supply line for supplying power from the battery 71 to each actuator is connected to the second relay contact of the power supply relay 70. One end of an ignition switch 72 is connected to the battery 71, and the other end of the ignition switch 72 is connected to an input port of the I / O interface 66.
[0046]
Further, the constant voltage circuit 67 is directly connected to the battery 71, and when the ON of the ignition switch 72 connected to the battery 71 is detected at the input port of the I / O interface 66 and the contact of the power relay 70 is closed, While supplying power to each unit in the ECU 60, backup power is always supplied to the backup RAM 64 regardless of whether the ignition switch 72 is ON or OFF.
[0047]
The knock sensor 40, the crank angle sensor 47, the cylinder discrimination sensor 50, and the vehicle speed sensor 51 are connected to input ports of the I / O interface 66. Further, an input port of the I / O interface 66 is connected via an A / D converter 69 to an intake air amount sensor 44, a throttle opening sensor 43, a cooling water temperature sensor 42, an absolute pressure sensor 38, and a battery. The voltage VB is input and monitored.
[0048]
On the other hand, the output ports of the I / O interface 66 include an ISC valve 18, an injector 33, a valve operation selecting mechanism 21, a waste gate valve control duty solenoid valve 32, an intake pipe pressure / atmospheric pressure switching solenoid valve 39, and a power supply. The relay coil of the relay 70 is connected via the drive circuit 68, and the igniter 36 is connected.
[0049]
When the ignition switch 72 is turned on, the power relay 70 is turned on, a constant voltage is supplied to each unit via the constant voltage circuit 67, and the ECU 60 executes various controls. That is, in the ECU 60, the CPU 61 inputs detection signals from various sensors via the I / O interface 66 based on the control program stored in the ROM 62, and various data stored in the RAM 63 and the backup RAM 64. Calculates various control amounts based on the fixed data stored in.
[0050]
Then, the ECU 60 determines the operation and non-operation of the first exhaust valve 7a and the second exhaust valve 7b, respectively, based on maps set in advance when the engine is cold and after the engine is warmed up, as shown in FIG. The selection is made in accordance with the exhaust valve operation control program shown in the flowchart, and a signal is output to the valve operation selection mechanism section 21 via the drive circuit 68.
[0051]
Further, the ECU 60 outputs a control signal to the waste gate valve control duty solenoid valve 32 via the drive circuit 68 to perform supercharging pressure control. Further, the ECU 60 outputs a drive pulse width signal that determines the calculated fuel injection amount to the injector 33 of the corresponding cylinder at a predetermined timing to perform fuel injection control, and outputs an ignition signal to the igniter 36 at a predetermined timing. To control the ignition timing and output a control signal to the ISC valve 18 to execute idle speed control and the like.
[0052]
Hereinafter, the exhaust valve operation control executed by the ECU 60 will be described with reference to the flowchart of FIG.
First, in step (hereinafter abbreviated as "S") 101, necessary parameters are read, and the routine proceeds to S102, where it is determined whether or not the engine 1 is in a cold state. If the result of this determination is that the engine 1 is in a cold state, the flow proceeds to S103, and refers to a region characteristic diagram (FIG. 5) for setting the operation and non-operation of the exhaust valve when the engine is in a cold state, which is stored in advance. Then, it is determined whether or not the operation state of the engine 1 is in the region A.
[0053]
If the result of determination in S103 is area A, the process proceeds to S104, in which each first exhaust valve 5a is closed and deactivated, and each second exhaust valve 5b is activated, and the program exits. That is, all the exhaust gas of the engine 1 is exhausted from each second exhaust valve 5b and passed through the second exhaust passage 23, whereby the first catalyst 24 is activated early and the exhaust gas is purified. Can be performed efficiently.
[0054]
Also, as a result of the determination in S103, if it is not the area A, that is, if it is the area B of high load and high rotation, the process proceeds to S105, and the first exhaust valve 5a and the second exhaust valve 5b are connected. Activate them together and exit the program. By setting the region B in this manner, even when the engine is cold, protection of the first catalyst 24 during high load and high rotation can be effectively performed.
[0055]
On the other hand, when it is determined in S102 that the engine is not in the cold state, the process proceeds to S106, and a region characteristic diagram (FIG. 6) for setting the operation and non-operation of the exhaust valve after the engine is warmed up in advance is stored. With reference to, it is determined whether or not the operating state of the engine 1 is in the region L (low load, low rotation region).
[0056]
If the result of determination in S106 is that the area is L, the process proceeds to S105, in which each first exhaust valve 5a and each second exhaust valve 5b are both operated, and the program exits. As described above, at the time of low load and low speed, by operating both the first exhaust valve 5a and the second exhaust valve 5b together, it is possible to improve the exhaust efficiency of the engine 1 and improve the fuel efficiency. In addition to the above, the effect of the first catalyst 24 and the second catalyst 26 can improve the exhaust gas purification performance.
[0057]
If the result of determination in S106 is not area L, the process proceeds to S107, and it is determined whether or not area M. As a result, in the case of the region M, the process proceeds to S108, in which each of the first exhaust valves 5a is operated, and each of the second exhaust valves 5b is closed and deactivated to exit the program. That is, in the case of the region M, the first exhaust valve 5a is operated and the second exhaust valve 5b is closed to be inactive, so that the exhaust gas bypasses the first catalyst 24 and the turbine 25 To improve the turbine efficiency and reduce the engine back pressure to generate high output. In addition, the exhaust blowdown pressure can be used effectively, so that supercharging characteristics better than those at low rotation speeds can be obtained, and traveling performance can be improved.
[0058]
On the other hand, if the result of determination in S107 is that the area is not the area M, that is, if the area is a high-load, high-speed area N, the process proceeds to S105, in which the first exhaust valve 5a and the second exhaust valve 5b are connected. Activate them together and exit the program. As described above, in the case of the region N in which the engine is in the high-speed, high-load operation state, the exhaust efficiency of the engine 1 is increased by operating each of the first exhaust valves 5a and each of the second exhaust valves 5b. And the maximum output can be improved, and the protection of the first catalyst 24 can be effectively performed in a high-speed, high-load operation state. It is also possible to prevent a decrease.
[0059]
Next, FIG. 7 is an explanatory diagram of the overall configuration of an engine with a turbocharger according to a second embodiment of the present invention. Note that the second embodiment has a structure in which the turbine of the turbocharger is divided into a first exhaust passage portion and a second exhaust passage portion having a smaller cross section than the first exhaust passage portion. Since there is a difference from the first embodiment, other configurations and operations are the same as those of the first embodiment, and therefore, the same reference numerals are given and the description is omitted.
[0060]
That is, as shown in FIG. 7, the turbine scroll portion of the turbine 81 of the turbocharger 80 according to the second embodiment has a first exhaust passage portion 82 and a cross section of the first exhaust passage portion 82. The small second exhaust passage portion 83 is formed so as to be divided into two exhaust passage portions.
[0061]
The first exhaust passage 82 of the turbine 81 communicates with the first exhaust passage 22 communicating with each first exhaust port 5a, and the second exhaust passage 83 communicates with the second exhaust passage 83. A second exhaust passage 23 communicated with the exhaust port 5b is communicated.
[0062]
The first exhaust valve 7a and the second exhaust valve 7b are operated or closed and non-operated according to a characteristic map when the engine is cold and after the engine is warmed up, as in the first embodiment. Controlled.
[0063]
As described above, the first exhaust passage portion 82 and the turbine 81 partitioned by the second exhaust passage portion 83 having a smaller cross section than the first exhaust passage portion 82 respectively form the first exhaust passage 22 and the first exhaust passage portion 82. By connecting and configuring the two exhaust passages 23, in addition to the effect described in the first embodiment, when the exhaust gas from the engine 1 is discharged through the second exhaust passage 23, the exhaust gas is supplied to the turbine 81. Since the throttled high-pressure exhaust gas is supplied, the supercharging effect can be improved. In addition, the first exhaust passage portion 82 of the turbine 81 has a sufficient cross section, and when discharging exhaust gas through the first exhaust passage 22, better supercharging characteristics than at low rotation speed are obtained. Performance can be improved.
[0064]
【The invention's effect】
As described above, according to the present invention, the turbine of the turbocharger is disposed at an optimum position, and the variable valve mechanism is appropriately controlled according to the operating state of the engine. It is possible to achieve both efficient improvement in engine output performance and improvement in exhaust gas purification performance.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an overall configuration of a turbocharged engine according to a first embodiment of the present invention.
FIG. 2 is an explanatory view of an exhaust passage connected to each exhaust port of each cylinder head.
FIG. 3 is a circuit diagram of an electronic control system according to the first embodiment;
FIG. 4 is a flowchart of exhaust valve operation control according to the first embodiment;
FIG. 5 is a region characteristic diagram for setting operation and non-operation of an exhaust valve when the engine is cold;
FIG. 6 is a region characteristic diagram for setting operation and non-operation of an exhaust valve after the engine is warmed up;
FIG. 7 is an explanatory view of the overall configuration of a turbocharged engine according to a second embodiment of the present invention.
[Explanation of symbols]
1 Engine with turbocharger
3 Cylinder head
5 Exhaust port
5a First exhaust port
5b Second exhaust port
7 Exhaust valve
7a First exhaust valve
7b Second exhaust valve
19 Turbocharger
21 Valve operation selection mechanism
22 First exhaust passage
23 Second exhaust passage
24 First catalyst
25 Turbine
26 Main catalyst (second catalyst)
60 ECU

Claims (9)

At least a first exhaust valve whose operation and non-operation can be controlled freely, and a second exhaust valve whose operation and non-operation can be controlled independently of the first exhaust valve are provided. An engine with a turbocharger comprising a plurality of cylinders each having a first exhaust port communicating therewith and a second exhaust port communicating with the second exhaust valve formed independently.
A first exhaust passage connected to the turbine inlet side of the turbocharger to collect and extract exhaust from each of the first exhaust ports; and a first exhaust passage connected to an intermediate portion of the first exhaust passage and A second exhaust passage for collecting and leading exhaust from the second exhaust port,
An engine with a turbocharger, wherein a first catalyst is interposed in the middle of the second exhaust passage, and a second catalyst is provided downstream of a turbine of the turbocharger. At least a first exhaust valve whose operation and non-operation can be controlled freely, and a second exhaust valve whose operation and non-operation can be controlled independently of the first exhaust valve are provided. A plurality of cylinders each independently having a first exhaust port communicating therewith and a second exhaust port communicating with the second exhaust valve are provided, and the turbine of the turbocharger is provided with at least a first exhaust passage portion. An engine with a turbocharger defined in a second exhaust passage section having a smaller cross section than the first exhaust passage section,
A first exhaust passage connected to an inlet side of a first exhaust passage portion of the turbine to collect and extract exhaust gas from each of the first exhaust ports; and an inlet side of a second exhaust passage portion of the turbine. And a second exhaust passage for connecting and exhausting the exhaust from each of the second exhaust ports.
An engine with a turbocharger, wherein a first catalyst is interposed in the middle of the second exhaust passage, and a second catalyst is provided downstream of a turbine of the turbocharger. 3. The turbocharger according to claim 1, wherein each of the first exhaust valves is closed and deactivated when the engine is cold, and the second exhaust valves are activated. With engine. When the engine operation is in a preset high-speed, high-load operation state while the engine is cold, the first exhaust valve and the second exhaust valve are operated. The engine with a turbocharger according to any one of claims 1 to 3. 5. The engine according to claim 1, wherein after the engine is warmed up, each of the first exhaust valves is operated, and each of the second exhaust valves is closed to be inoperative. 6. Engine with turbocharger. After the engine is warmed up, when the engine operation is in a preset high-speed, high-load operation state, the first exhaust valve and the second exhaust valve are operated. The engine with a turbocharger according to any one of claims 1 to 5. After the engine warms up, when the engine operation is in a preset low rotation, low load operation state, the first exhaust valve and the second exhaust valve are operated. The turbocharged engine according to any one of claims 1 to 6. The turbocharger according to any one of claims 1 to 7, wherein the first exhaust ports of the cylinders are connected to the first exhaust passage after being merged. engine. The turbocharger according to any one of claims 1 to 8, wherein the second exhaust ports of the cylinders are connected to the second exhaust passage after being merged. engine.

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