JP2004060546A - Internal combustion engine - Google Patents

Internal combustion engine Download PDF

Info

Publication number
JP2004060546A
JP2004060546A JP2002220657A JP2002220657A JP2004060546A JP 2004060546 A JP2004060546 A JP 2004060546A JP 2002220657 A JP2002220657 A JP 2002220657A JP 2002220657 A JP2002220657 A JP 2002220657A JP 2004060546 A JP2004060546 A JP 2004060546A
Authority
JP
Japan
Prior art keywords
air
combustion chamber
exhaust
air supply
passage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2002220657A
Other languages
Japanese (ja)
Inventor
Yasushi Yoshimura
吉村 裕史
Original Assignee
Toyota Motor Corp
トヨタ自動車株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toyota Motor Corp, トヨタ自動車株式会社 filed Critical Toyota Motor Corp
Priority to JP2002220657A priority Critical patent/JP2004060546A/en
Publication of JP2004060546A publication Critical patent/JP2004060546A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00Road transport of goods or passengers
    • Y02T10/10Internal combustion engine [ICE] based vehicles
    • Y02T10/12Improving ICE efficiencies

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology capable of increasing the output torque characteristics of an internal combustion engine with a secondary air supply part. <P>SOLUTION: This internal combustion engine comprises an exhaust gas passage allowing exhaust gas exhausted from a plurality of combustion chambers to pass therethrough, connected to the plurality of combustion chambers, and having a plurality of partial exhaust passages allowed to communicate with each other through merging points on the downstream sides thereof and a secondary air passage connected to a secondary air supply source and having a plurality of partial secondary air passages allowed to communicate with each other through branch points on the upstream sides thereof. When both the exhaust port of the first combustion chamber and the exhaust port of the second combustion chamber are set in open states, the first and second combustion chambers #1 and #2 having a sequential combustion order are allowed to communicate with each other through a first route P1 including a merging point N1 and allowed to communicate with a second route P2 including a branch point N2. The length of the second route P2 is set approximately equal to that of the first route P1. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an internal combustion engine provided with a secondary air supply.
[0002]
[Prior art]
Exhaust gas discharged from a plurality of combustion chambers of an internal combustion engine usually contains harmful components such as carbon monoxide, hydrocarbon compounds, and nitrogen oxides. In recent years, reduction of these harmful components has been strongly demanded. For this reason, the internal combustion engine is usually provided with a catalyst device for converting harmful components in exhaust gas into harmless gas.
[0003]
The catalyst device can efficiently treat harmful components in exhaust gas when the catalyst temperature is equal to or higher than the activation temperature. Therefore, when the catalyst temperature is relatively low, the catalyst device cannot efficiently treat the harmful components. For this reason, the internal combustion engine may be provided with a secondary air supply unit.
[0004]
The secondary air supply usually includes a secondary air supply and a secondary air passage connected to the secondary air supply. The secondary air passage includes, on the most downstream side, a plurality of partial secondary air passages corresponding to the plurality of combustion chambers, and the partial secondary air passages communicate with each other via an upstream branch point. I have. The secondary air is supplied to the vicinity of the exhaust ports of the plurality of combustion chambers via the secondary air passage, and as a result, unburned fuel in the exhaust gas is burned. Due to this combustion heat, the temperature of the exhaust gas increases, and as a result, the catalyst temperature can be increased in a relatively short time. Such a secondary air supply unit is disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 7-180547.
[0005]
[Problems to be solved by the invention]
However, conventionally, there has been a problem that the output torque characteristic of the internal combustion engine is deteriorated by adding the secondary air supply unit. This means that, with respect to any first and second combustion chambers in which the combustion order is continuous, the exhaust pressure when the exhaust port of the second combustion chamber is set to the open state is set to the first through the secondary air passage. This is because the time of reaching the exhaust port of the combustion chamber and the overlap period in which the intake port and the exhaust port of the first combustion chamber are set in the open state overlap. At this time, the first combustion chamber cannot take in air sufficiently, and as a result, the output torque of the internal combustion engine decreases.
[0006]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems in the related art, and has as its object to provide a technique capable of improving output torque characteristics of an internal combustion engine including a secondary air supply unit.
[0007]
[Means for Solving the Problems and Their Functions and Effects]
In order to solve at least a part of the above problems, a first device of the present invention is an internal combustion engine,
Multiple combustion chambers,
An exhaust passage through which exhaust gas discharged from the plurality of combustion chambers passes, the exhaust passage including a plurality of partial exhaust passages connected to the plurality of combustion chambers and communicating with each other via a downstream junction; ,
A secondary air supply unit for supplying secondary air into the exhaust passage,
With
The secondary air supply unit,
A secondary air supply,
A secondary air passage connected to the secondary air supply source, the secondary air passage including a plurality of partial secondary air passages communicating with each other via an upstream branch point,
With
In any of the first and second combustion chambers in which the combustion order is continuous among the plurality of combustion chambers, both the exhaust port of the first combustion chamber and the exhaust port of the second combustion chamber are open. When set to, while communicating via a first path including the junction, and communicating via a second path including the branch point,
The length of the second path is set substantially equal to the length of the first path.
[0008]
In the first device, the length of the second path passing through the secondary air passage is set substantially equal to the length of the first path passing through the exhaust passage. Therefore, the first time when the exhaust pressure when the exhaust port of the second combustion chamber is set to the open state reaches the exhaust port of the first combustion chamber via the first path, and the second time The second time at which the gas reaches the exhaust port of the first combustion chamber via the path substantially coincides with the second time.
[0009]
When the length of the second route is different from the length of the first route, the first time and the second time are different. In such a case, a decrease in the output torque may occur in the two rotation speed regions of the internal combustion engine due to the exhaust pressure of the second combustion chamber.
[0010]
However, when the first device of the present invention is employed, the rotation speed at which the output torque decreases due to the exhaust pressure of the second combustion chamber can be limited to one rotation speed region. . That is, the output torque characteristics of the internal combustion engine including the secondary air supply unit can be improved.
[0011]
In the above device,
The plurality of partial secondary air passages correspond to each of the plurality of combustion chambers,
Each of the partial secondary air passages may supply secondary air into each of the partial exhaust passages.
[0012]
In this case, the unburned fuel in the exhaust gas can be efficiently burned.
[0013]
Further, in the above device,
The length of the second path is such that the exhaust pressure when the exhaust port of the second combustion chamber is set to the open state reaches the exhaust port of the first combustion chamber via the second path. And the overlap period in which the intake port and the exhaust port of the first combustion chamber are set to the open state overlaps with each other, the rotational speed of the internal combustion engine is the minimum value in the normally used rotational speed range. Preferably, it is set so as to be smaller.
[0014]
With this configuration, it is possible to suppress a decrease in output torque when the internal combustion engine is operated in a rotational speed range where the internal combustion engine is normally used.
[0015]
A second device of the present invention is an internal combustion engine,
Multiple combustion chambers,
An exhaust passage through which exhaust gas discharged from the plurality of combustion chambers passes;
A secondary air supply unit for supplying secondary air into the exhaust passage,
With
The secondary air supply unit,
A secondary air supply,
A secondary air passage connected to the secondary air supply source, the secondary air passage including a plurality of partial secondary air passages communicating with each other via an upstream branch point,
With
In any of the first and second combustion chambers in which the combustion order is continuous among the plurality of combustion chambers, both the exhaust port of the first combustion chamber and the exhaust port of the second combustion chamber are open. When set to, communication via the path including the branch point,
The length of the path is determined by the time when the exhaust pressure when the exhaust port of the second combustion chamber is set to the open state reaches the exhaust port of the first combustion chamber via the path, and The overlap period in which the intake port and the exhaust port of the first combustion chamber are set to the open state and the rotation speed of the internal combustion engine when the overlap period is smaller than the minimum value of the rotation speed range that is normally used. It is characterized by being set.
[0016]
In the second device, the length of the path passing through the secondary air passage is set such that the rotation speed of the internal combustion engine at which the output torque is reduced is smaller than the minimum value in the rotation speed region that is normally used. I have. Therefore, it is possible to suppress a decrease in the output torque when the internal combustion engine is operated in a rotation speed region where the internal combustion engine is normally used, and as a result, to improve the output torque characteristics of the internal combustion engine including the secondary air supply unit. Becomes possible.
[0017]
In the above device,
The exhaust passage includes a plurality of partial exhaust passages respectively connected to the plurality of combustion chambers,
The plurality of partial secondary air passages correspond to each of the plurality of combustion chambers,
Each of the partial secondary air passages may supply secondary air into each of the partial exhaust passages.
[0018]
In this case, the unburned fuel in the exhaust gas can be efficiently burned.
[0019]
A third device of the present invention is an internal combustion engine,
Multiple combustion chambers,
An exhaust passage through which exhaust gas discharged from the plurality of combustion chambers passes;
A secondary air supply unit for supplying secondary air into the exhaust passage,
With
The secondary air supply unit,
A secondary air supply,
A secondary air passage connected to the secondary air supply source, the secondary air passage including a plurality of partial secondary air passages communicating with each other via an upstream branch point,
With
In any of the first and second combustion chambers in which the combustion order is continuous among the plurality of combustion chambers, both the exhaust port of the first combustion chamber and the exhaust port of the second combustion chamber are open. When set to, communication via the path including the branch point,
The secondary air supply unit further includes:
A damping unit is provided in the middle of the path and attenuates a pressure fluctuation in the secondary air passage.
[0020]
In the third device, since the damping section is provided in the middle of the path passing through the secondary air passage, the exhaust pressure of the second combustion chamber reaches the exhaust port of the first combustion chamber via the path. And the overlap period in which the intake port and the exhaust port of the first combustion chamber are set in the open state overlaps with each other, the exhaust pressure of the second combustion chamber increases through the path. The pressure at the time of reaching the inside of the first combustion chamber can be made relatively low. Therefore, it is possible to improve the output torque characteristics of the internal combustion engine including the secondary air supply unit.
[0021]
A fourth device of the present invention is an internal combustion engine,
Multiple combustion chambers,
An exhaust passage through which exhaust gas discharged from the plurality of combustion chambers passes;
A secondary air supply unit for supplying secondary air into the exhaust passage,
With
The secondary air supply unit,
A secondary air supply,
A secondary air passage connected to the secondary air supply source, the secondary air passage including a plurality of partial secondary air passages communicating with each other via an upstream branch point,
With
In any of the first and second combustion chambers in which the combustion order is continuous among the plurality of combustion chambers, both the exhaust port of the first combustion chamber and the exhaust port of the second combustion chamber are open. When set to, communication via the path including the branch point,
The secondary air supply unit further includes:
Comprising a shut-off valve provided in the middle of the path,
The internal combustion engine further comprises:
A control unit for controlling the operation of the shut-off valve,
The control unit sets the shut-off valve to an open state during a driving period of the secondary air supply source, and sets the shut-off valve to a closed state during a stop period of the secondary air supply source. Features.
[0022]
In the fourth device, a shut-off valve is provided in the middle of a path passing through the secondary air passage, and the shut-off valve is set to a closed state during a stop period of the secondary air supply source. Therefore, when the secondary air is not supplied into the exhaust passage, the first combustion chamber is not affected by the exhaust pressure of the second combustion chamber, and as a result, the internal combustion engine having the secondary air supply unit is not affected. Output torque characteristics can be improved.
[0023]
A fifth device of the present invention is an internal combustion engine,
Multiple combustion chambers,
An exhaust passage through which exhaust gas discharged from the plurality of combustion chambers passes;
A secondary air supply unit for supplying secondary air into the exhaust passage,
With
The secondary air supply unit,
A secondary air supply,
A secondary air passage connected to the secondary air supply source, the secondary air passage including a plurality of partial secondary air passages communicating with each other via an upstream branch point and corresponding to each of the plurality of combustion chambers. A secondary air passage;
With
In any of the first and second combustion chambers in which the combustion order is continuous among the plurality of combustion chambers, both the exhaust port of the first combustion chamber and the exhaust port of the second combustion chamber are open. When set to, communication via the path including the branch point,
The secondary air supply unit further includes:
Comprising a plurality of the shut-off valves provided in each of the plurality of partial secondary air passages,
The internal combustion engine further comprises:
A control unit for controlling the operation of the plurality of shut-off valves,
The control unit may be configured to control the exhaust pressure when the exhaust port of the second combustion chamber is set to the open state to reach the first shutoff valve corresponding to the first combustion chamber via the path. The first shutoff valve is set to a closed state.
[0024]
In the fifth device, during the overlap period of the first combustion chamber, the exhaust pressure when the exhaust port of the second combustion chamber is set to the open state is set to the first pressure via the path passing through the secondary air passage. Each shut-off valve provided for each combustion chamber is set to a closed state so as not to reach the exhaust port of the combustion chamber. Therefore, the first combustion chamber is not affected by the exhaust pressure of the second combustion chamber, and as a result, it is possible to improve the output torque characteristics of the internal combustion engine including the secondary air supply unit.
[0025]
A sixth device of the present invention is an internal combustion engine,
Multiple combustion chambers,
An exhaust passage through which exhaust gas discharged from the plurality of combustion chambers passes;
A secondary air supply unit for supplying secondary air into the exhaust passage,
With
The plurality of combustion chambers are divided into a plurality of groups,
The secondary air supply unit, for each of the groups,
A secondary air supply,
A secondary air passage connected to the secondary air supply,
With
Arbitrary first and second combustion chambers of the plurality of combustion chambers whose combustion order is continuous belong to different groups.
[0026]
In the sixth device, since the first combustion chamber and the second combustion chamber belong to different groups, both the exhaust port of the first combustion chamber and the exhaust port of the second combustion chamber are open. Even in the case where the state is set, the first combustion chamber and the second combustion chamber do not communicate with each other via a path passing through the secondary air passage. Therefore, it is possible to improve the output torque characteristics of the internal combustion engine including the secondary air supply unit.
[0027]
In the above device,
The number of the plurality of combustion chambers and the number of the plurality of groups may be equal.
[0028]
In this case, each combustion chamber does not communicate with any other combustion chamber via a path passing through the secondary air passage. Therefore, since each combustion chamber is not affected by the exhaust pressure of the other combustion chambers, the output torque characteristics can be considerably improved.
[0029]
Further, in the first to sixth devices,
It is preferable that a catalyst device for purifying exhaust gas is provided in the exhaust passage.
[0030]
The present invention can be realized in various modes such as a secondary air supply unit, an internal combustion engine including the secondary air supply unit, and a device such as a moving body equipped with the internal combustion engine.
[0031]
BEST MODE FOR CARRYING OUT THE INVENTION
A. First embodiment:
A-1. Engine configuration:
Next, embodiments of the present invention will be described based on examples. FIG. 1 is an explanatory diagram illustrating a schematic configuration of a gasoline engine 100 according to the first embodiment. The engine of this embodiment is mounted on a vehicle.
[0032]
The engine 100 includes an engine body 10, an intake pipe 40, an exhaust pipe 50, and a secondary air supply unit 200.
[0033]
The engine body 10 is a so-called V-type six-cylinder engine, and has six combustion chambers # 1 to # 6. The engine body 10 has two banks arranged in a V-shape. The first bank includes three combustion chambers # 1, # 3, and # 5, and the second bank includes Includes the other three combustion chambers # 2, # 4, and # 6.
[0034]
The intake pipe 40 forms an intake passage. The intake passage has a multi-stage structure in which the number of partial passages included in each stage gradually increases toward the downstream side. Specifically, one partial passage 41 is provided in the most upstream stage, and six partial passages 42a to 42f, in which the one partial passage is branched, are provided in the most downstream stage. The six partial passages 42a to 42f correspond to the six combustion chambers # 1 to # 6, respectively.
[0035]
The exhaust pipe 50 forms an exhaust passage. The exhaust passage has a multi-stage structure in which the number of partial passages included in each stage gradually decreases toward the downstream side. Specifically, the uppermost stream stage is provided with six partial passages 51a to 51f corresponding to each of the six combustion chambers. In the middle stage, a first partial passage 52a where the three partial passages 51a, 51c and 51e of the most upstream stage merge, a second partial passage 52b where the other three partial passages 51b, 51d and 51f merge, Is provided. At the most downstream stage, there is provided one partial passage 53 where the two middle partial passages 52a and 52b merge.
[0036]
The exhaust passage is provided with four catalytic devices 61 to 64 for purifying exhaust gas. The first and second catalyst devices 61 and 62 are provided in the middle first partial passage 52a, and the third and fourth catalyst devices 63 and 64 are provided in the middle second partial passage 52b. Has been. Each of the catalyst devices 61 to 64 has a catalyst containing an active component composed of a base material layer, an active metal, and a co-catalyst, and has a harmful component (carbon monoxide, hydrocarbon-based Compounds, nitrogen oxides, etc.) into harmless gases.
[0037]
The secondary air supply unit 200 includes a secondary air pump 210 and a secondary air pipe 220. The secondary air pipe 220 forms a secondary air passage. The secondary air passage has a multi-stage structure in which the number of partial passages included in each stage gradually increases toward the downstream side. Specifically, the uppermost stage is provided with one partial passage 221 connected to the secondary air pump 210, and the middle stage is provided with two partial passages 222a, 222a 222b is provided. At the most downstream stage, three partial passages 223a, 223c, and 223e where the middle first partial passage 222a is branched, and three partial passages 223b, 223d and 223f where the middle second partial passage 222b is branched. Is provided. The six most downstream passages 223a to 223f correspond to the six combustion chambers # 1 to # 6, respectively, and are respectively connected to the six most upstream passages 51a to 51f of the exhaust passage. I have.
[0038]
The secondary air supply unit 200 supplies the secondary air into the partial passages 51a to 51f at the most upstream stage of the exhaust passage. As a result, the unburned fuel in the exhaust gas burns, and the temperature of the exhaust gas rises due to the combustion heat. Then, the exhaust gas having a relatively high temperature is supplied to the catalyst devices 61 to 64, so that the catalyst temperature rises to the activation temperature or higher in a relatively short time. Here, the activation temperature means a temperature at which the catalytic reaction proceeds autonomously. As described above, when the secondary air supply unit 200 is used, for example, when the catalyst temperature is relatively low such as at the start of operation of the engine, the catalyst can be activated in a relatively short time. The catalyst devices 61 to 64 can efficiently treat harmful components in the exhaust gas.
[0039]
The engine 100 includes an electronic control unit (ECU) 90 for controlling the entire engine. In particular, the ECU 90 controls the operation of the secondary air pump 210 according to the measurement results of the four temperature sensors 91 to 94 provided in the four catalyst devices 61 to 64, respectively. Specifically, when the measurement result of each of the temperature sensors 91 to 94 indicates that the temperature is lower than the activation temperature, the secondary air pump 210 is driven (rotated), and when the measurement result indicates that the temperature is higher than the activation temperature. Then, the secondary air pump 210 is stopped.
[0040]
FIG. 2 is an explanatory diagram schematically showing the internal configuration of the engine body 10 of FIG. However, FIG. 2 is drawn focusing on the first combustion chamber # 1.
[0041]
The engine body 10 includes a cylinder block 20 and a cylinder head 30, and a first combustion chamber # 1 is formed between the cylinder block 20 and the cylinder head 30.
[0042]
The cylinder block 20 includes a cylinder 22 and a crankcase 24. A piston 26 that reciprocates up and down is provided in the cylinder 22, and a crankshaft 28 that rotates is provided in the crankcase 24. The piston 26 and the crankshaft 28 are connected via a connecting rod 27. With this configuration, conversion between the reciprocating motion of the piston 26 and the rotational motion of the crankshaft 28 is performed.
[0043]
An intake port 31 and an exhaust port 32 are formed in the cylinder head 30. An intake valve 33 is arranged in the intake port 31, and the opening / closing state of the intake port of the combustion chamber # 1 is controlled by the opening / closing operation of the intake valve 33. An exhaust valve 34 is disposed in the exhaust port 32, and the opening and closing operation of the exhaust valve 34 controls the open / close state of the exhaust port of the combustion chamber # 1.
[0044]
An intake pipe 40 is connected to the intake port 31, and an exhaust pipe 50 is connected to the exhaust port 32. The passage in the intake port 31 forms a part of the partial passage 42a at the most downstream stage of the intake passage, and the passage in the exhaust port 32 forms a part of the partial passage 51a at the most upstream stage of the exhaust passage.
[0045]
A throttle valve 46 and a fuel injection section 48 are provided in the intake passage. Air is supplied from the upstream side of the intake passage, and the throttle valve 46 adjusts the amount of air taken into the combustion chamber # 1. The fuel injection unit 48 injects fuel (gasoline) supplied from a fuel pump (not shown) into the intake passage. Thus, a mixture of air and fuel is generated. After the mixture is supplied into the combustion chamber # 1, it is burned by the electric spark formed by each spark plug 36. The burned exhaust gas is discharged from the combustion chamber # 1. A secondary air pipe 220 is inserted into the exhaust port 32, and when secondary air is supplied into the exhaust passage, unburned fuel in the exhaust gas burns.
[0046]
In the present embodiment, the throttle valve 46 and the fuel injection unit 48 are provided for each combustion chamber, and the intake pipe 40, the throttle valve 46, and the fuel injection unit 48 supply air and fuel to each combustion chamber. It functions as an air-fuel mixture introduction unit for introducing an air-fuel mixture including
[0047]
FIG. 3 is an explanatory diagram schematically showing the operation strokes of the six combustion chambers # 1 to # 6 of FIG. As shown, the combustion (expansion) in the six combustion chambers is performed in the order of # 1, # 2, # 3, # 4, # 5, and # 6. Each combustion chamber repeatedly executes four strokes of suction, compression, expansion, and exhaust. The expansion stroke in each combustion chamber is started with a delay of about 120 ° at a rotation angle of the crankshaft 28 (FIG. 2) (hereinafter, also referred to as “crank rotation angle”).
[0048]
Incidentally, as shown in FIG. 3, the intake port of each combustion chamber is set to an open state from before the end of the exhaust stroke to after the start of the compression stroke. Further, the exhaust port of each combustion chamber is set to an open state from before the end of the expansion stroke to after the start of the suction stroke. Therefore, when each combustion chamber shifts from the exhaust stroke to the intake stroke, there is a period in which both the intake port and the exhaust port are set to the open state. This period is called "overlap period". By providing the overlap period, exhaust gas can be efficiently discharged from each combustion chamber, and air can be efficiently sucked into each combustion chamber. In other words, by providing the overlap period, the intake and exhaust efficiency of each combustion chamber can be improved.
[0049]
Further, as shown in FIG. 1, the exhaust passage connected to each combustion chamber has a structure in which gas can freely flow. Therefore, any two combustion chambers in a continuous combustion order can communicate via the exhaust passage. For example, the two partial passages 51a and 51b at the most upstream stage connected to the first and second combustion chambers # 1 and # 2 communicate with each other via a downstream junction N1. When both the exhaust port of the first combustion chamber # 1 and the exhaust port of the second combustion chamber # 2 are set to the open state, the first and second combustion chambers # 1, # 2 Communicate with each other via a first path P1 including the junction N1.
[0050]
In such a case, the output torque decreases when the engine operates in a specific rotation speed region, and as a result, the output torque characteristics may deteriorate. Specifically, immediately after the exhaust port of the second combustion chamber # 2 is set to the open state, a pulsed high exhaust pressure is generated. This exhaust pressure is also called “blowdown pressure”. This exhaust pressure propagates as a pressure wave at a substantially sonic speed along the first path P1 in the exhaust passage, and reaches the exhaust port of the first combustion chamber # 1. When the arrival time overlaps with the overlap period of the first combustion chamber # 1, the pressure near the exhaust port becomes higher than the pressure near the intake port, so that the exhaust gas enters the first combustion chamber # 1. Gas flows in. At this time, the first combustion chamber # 1 cannot take in air sufficiently in the suction stroke, and as a result, the output torque of the engine decreases.
[0051]
For this reason, in the present embodiment, the output torque characteristics of the engine are improved by adjusting the length of the exhaust pipe 50 (path P1). That is, the first time until the exhaust pressure generated in the second combustion chamber # 2 reaches the exhaust port of the first combustion chamber # 1 via the first path P1 is equal to the first time of the first path P1. Determined by length, independent of engine speed. Specifically, the first time becomes longer as the first route P1 is longer. On the other hand, the second time from the time when the exhaust port of the second combustion chamber # 2 is in the open state to the overlap period of the first combustion chamber # 1 is determined by the engine speed, and the first path P1 Does not depend on the length. Specifically, the second time increases as the engine speed decreases. Therefore, in the present embodiment, the length of the exhaust pipe 50 is adjusted to adjust the rotation speed region where the output torque is reduced.
[0052]
FIG. 4 is a graph showing the relationship between the engine speed and the output torque when the length of the exhaust pipe 50 is changed. However, FIG. 4 shows a relationship when the engine is not provided with the secondary air supply unit 200.
[0053]
Curve C1 shows the relationship when the exhaust pipe 50 (path P1) is set relatively short, and curve C2 shows the relationship when the exhaust pipe 50 (path P1) is set relatively long. I have. As can be seen by comparing the two curves C1 and C2, in the curve C1, the output torque decreases in a region near the engine speed n. The rotation speed n is, for example, about 2000 rpm.
[0054]
FIG. 5 is an explanatory diagram showing exhaust pulsation at the engine speed n of FIG. Curves D1 and D2 in FIG. 5 correspond to curves C1 and C2 in FIG. In FIG. 5, the pressure change measured near the exhaust port 32 of the first combustion chamber # 1 is shown in a crank rotation angle range of about 720 °. FIG. 5 shows the open period of the exhaust port, the open period of the intake port, and the overlap period for the first combustion chamber # 1.
[0055]
The first peak Ba of the curve D2 is caused by the pressure generated in the first combustion chamber # 1 (that is, the pressure when the exhaust port of the first combustion chamber # 1 is set to the open state). . The pressure generated when the pressure generated in the sixth combustion chamber # 6 propagates to the vicinity of the exhaust port 32 of the first combustion chamber # 1 is superimposed on the first peak Ba. Similarly, the second peak Bb is caused by the pressure generated in the third combustion chamber # 3 and the pressure generated in the second combustion chamber # 2. Further, the third peak Bc is due to the pressure generated in the fifth combustion chamber # 5 and the pressure generated in the fourth combustion chamber # 4.
[0056]
As can be seen by comparing the two curves D1 and D2 of FIG. 5, in the curve D1, the peak caused by the pressure generated in the second combustion chamber # 2 is the first peak Ba and the second peak of the curve D2. It appears between the peak Bb. This is because the time required for the exhaust pressure generated in the second combustion chamber # 2 to reach the exhaust port of the first combustion chamber # 1 via the relatively short first path P1 is relatively short. is there. In the curve D1, the time when the exhaust pressure generated in the second combustion chamber # 2 reaches the exhaust port of the first combustion chamber # 1 overlaps with the overlap period of the first combustion chamber # 1. . At this time, the first combustion chamber # 1 cannot sufficiently intake air in the intake stroke, and as a result, the torque decreases as shown by the curve C1 in FIG.
[0057]
In the curve D1, the peak caused by the pressure generated in the fourth combustion chamber # 4 appears between the second peak Bb and the third peak Bc of the curve D2, and the sixth combustion chamber The peak caused by the pressure generated in # 6 appears between the third peak Bc and the first peak Ba of the curve D2.
[0058]
In this embodiment, as shown by the curve C2 in FIG. 4 and the curve D2 in FIG. 5, the length of the exhaust pipe 50 (path P1) is set such that the exhaust port of the second combustion chamber # 2 is open. Engine speed when the time when the exhaust pressure reaches the exhaust port of the first combustion chamber # 1 via the first path P1 and the overlap period of the first combustion chamber # 1 overlap ( Hereinafter, it is set such that the “first synchronous rotation speed” is smaller than the minimum value of the normally used rotation speed region (hereinafter, also simply referred to as “normal rotation speed region”). That is, in the curve C2 in FIG. 4, the torque decrease does not occur in the illustrated normal rotation speed region, but occurs in the illustrated low rotation speed region.
[0059]
If the length of the exhaust pipe 50 (path P1) is set as described above, it is possible to suppress a decrease in output torque when the engine operates in the normal rotation speed region.
[0060]
4 and 5, the case where the engine does not include the secondary air supply unit 200 has been described. However, the engine 100 according to the present embodiment includes the secondary air supply unit 200. Therefore, the above-described problem of a decrease in torque can similarly occur in the secondary air supply unit 200.
[0061]
That is, as shown in FIG. 1, the secondary air passage connected near the exhaust port of each combustion chamber has a structure in which gas can freely flow. Therefore, any two combustion chambers in a continuous combustion order can communicate via the secondary air passage. For example, the two lowermost-stage partial passages 223a and 223b connected to the first and second combustion chambers # 1 and # 2 communicate with each other via an upstream branch point N2. When both the exhaust port of the first combustion chamber # 1 and the exhaust port of the second combustion chamber # 2 are set to the open state, the first and second combustion chambers # 1, # 2 Communicate with each other via a second path P2 including the branch point N2. Therefore, the exhaust pressure generated when the exhaust port of the second combustion chamber # 2 is set to the open state propagates as a pressure wave at the substantially sonic speed through the second path P2 in the secondary air passage. It reaches the exhaust port of combustion chamber # 1. If the arrival time overlaps the overlap period of the first combustion chamber # 1, the output torque of the engine will decrease.
[0062]
For this reason, in the present embodiment, similarly to the exhaust pipe 50 (path P1), by adjusting the length of the secondary air pipe 220 (path P2), the rotation speed region where the output torque is reduced is adjusted. As a result, the output torque characteristics of the engine are improved.
[0063]
FIG. 6 is a graph showing the relationship between the engine speed and the output torque when the length of the secondary air pipe 220 is changed, and corresponds to FIG. However, FIG. 6 shows the relationship when the exhaust pipe 50 (path P1) is set to be relatively long as shown by the curve C2 in FIG. 4 and the curve D2 in FIG.
[0064]
A curve C3 shows a relationship when the secondary air pipe 220 (path P2) is set relatively short, and a curve C4 shows a case where the secondary air pipe 220 (path P2) is set relatively long. Shows the relationship. More specifically, in the curve C3, the length of the secondary air pipe 220 (path P2) is set substantially equal to the length of the exhaust pipe 50 (path P1) shown in the curve C1 of FIG. In FIG. 4, the length of the secondary air pipe 220 (path P2) is set substantially equal to the length of the exhaust pipe 50 (path P1) shown by the curve C2 in FIG. As can be seen by comparing the two curves C3 and C4, in the curve C3, as in the case of the curve C1 in FIG. 4, the output torque decreases in the region near the engine speed n. Note that the curve C4 substantially coincides with the curve C2 in FIG.
[0065]
FIG. 7 is an explanatory diagram showing the exhaust pulsation at the engine speed n of FIG. 6, and corresponds to FIG. Curves D3 and D4 in FIG. 7 correspond to curves C3 and C4 in FIG.
[0066]
The curve D4 substantially matches the curve D2 in FIG. As can be seen by comparing the two curves D3 and D4 in FIG. 7, in the curve D3, similarly to the curve D1 in FIG. 5, the peak caused by the pressure generated in the second combustion chamber # 2 is the same as the curve D4 in FIG. It appears between the first peak Ba and the second peak Bb. This is because the time required for the exhaust pressure generated in the second combustion chamber # 2 to reach the exhaust port of the first combustion chamber # 1 via the relatively short second path P2 is relatively short. is there. In the curve D3, the time when the exhaust pressure generated in the second combustion chamber # 2 reaches the exhaust port of the first combustion chamber # 1 overlaps the overlap period of the first combustion chamber # 1. . At this time, the first combustion chamber # 1 cannot take in air sufficiently in the suction stroke, and as a result, the torque decreases as shown by the curve C3 in FIG.
[0067]
In the present embodiment, as shown by the curve C4 in FIG. 6 and the curve D4 in FIG. 7, the length of the secondary air pipe 220 (path P2) depends on the exhaust pressure generated in the second combustion chamber # 2. The engine speed (hereinafter simply referred to as “second engine speed”) when the time when the vehicle reaches the exhaust port of the first combustion chamber # 1 via the path P2 and the overlap period of the first combustion chamber # 1 overlaps each other. (Also referred to as “synchronous rotation speed”) is set to be smaller than the minimum value of the rotation speed region (normal rotation speed region) that is normally used. That is, in the curve C4 of FIG. 6, the torque decrease does not occur in the illustrated normal rotation speed region but occurs in the illustrated low rotation speed region.
[0068]
If the length of the secondary air pipe 200 (path P2) is set as described above, it is possible to suppress a decrease in output torque when the engine operates in the normal rotation speed region.
[0069]
Note that the normal rotation speed range may vary depending on the configuration of the engine. In this embodiment, the normal rotation speed region is, for example, about 1000 to about 6000 rpm. The first and second synchronous rotation speeds are set to, for example, rotation speeds within a range from about 500 to about 700 rpm, which is smaller than the minimum value (about 1000 rpm) in the normal rotation speed region.
[0070]
As described above, in the present embodiment, by adjusting both the exhaust pipe 50 (path P1) and the secondary air pipe 220 (path P2), as shown in the curve C4 of FIG. 6 and the curve D4 of FIG. Thus, a decrease in torque in a region near the engine speed n is suppressed.
[0071]
In the above description, the description has been given focusing on the relationship between the first combustion chamber # 1 and the second combustion chamber # 2. However, the other two combustion chambers (that is, the combustion chambers # 2 and The same applies to combustion chamber # 3, combustion chamber # 3, combustion chamber # 4, combustion chamber # 4, combustion chamber # 5, combustion chamber # 5, combustion chamber # 6, combustion chamber # 6, and combustion chamber # 1). .
[0072]
As described above, the engine 100 according to the present embodiment includes the plurality of combustion chambers # 1 to # 6, the exhaust pipe 50 that forms the exhaust passage, and the secondary air supply unit that supplies the secondary air into the exhaust passage. 200. The first and second combustion chambers # 1 and # 2, in which the combustion order is continuous among the plurality of combustion chambers, are connected between the exhaust port of the first combustion chamber # 1 and the exhaust port of the second combustion chamber # 2. When both are set to the open state, they communicate via a first path P1 including a junction N1 and communicate via a second path P2 including a branch point N2.
[0073]
In the present embodiment, the length of the second path P2 is set substantially equal to the length of the first path P1. Note that “the length of the second path is substantially equal to the length of the first path” means that the length of the second path is within ± 15% of the length of the first path. Means that. However, the length of the second path is more preferably within ± 10% of the length of the first path, and more preferably within ± 5%. By employing this configuration, the first and second synchronous rotation speeds can be made substantially equal. That is, the first time when the exhaust pressure when the exhaust port of the second combustion chamber # 2 is set to the open state reaches the exhaust port of the first combustion chamber # 1 via the first path P1; And the second time at which the gas reaches the exhaust port of the first combustion chamber # 1 via the second path P2 is substantially matched, and the output torque of the second combustion chamber # 2 is reduced due to the exhaust pressure of the second combustion chamber # 2. The rotation speed at which the reduction occurs can be limited to one rotation speed region. That is, the output torque characteristics of the engine 100 including the secondary air supply unit 200 can be improved.
[0074]
In the present embodiment, the length of the second path P2 (substantially equal to the length of the first path P1) is set relatively long. Specifically, the length of the second path P2 is such that the exhaust pressure when the exhaust port of the second combustion chamber # 2 is set to the open state is increased via the second path P2 to the first combustion chamber. The number of revolutions of the engine when the time of reaching the exhaust port of # 1 and the overlap period in which the intake port and the exhaust port of the first combustion chamber # 1 are set to the open state overlap each other is usually used. It is set so as to be smaller than the minimum value in the rotation speed region. By adopting this configuration, the second synchronous rotation speed (substantially equal to the first synchronous rotation speed) can be set to a value smaller than the minimum value in the normal rotation speed region, and as a result, the engine is normally used. It is possible to suppress a decrease in output torque when the operation is performed in the rotation speed region.
[0075]
In the present embodiment, the first path P1 and the second path P2 are set to have substantially the same length, but may be set to different lengths instead. For example, the length of the first route P1 may be set to be longer or shorter than the length of the second route P2. However, when the length of the first path P1 is different from the length of the second path P2, the exhaust pressure when the exhaust port of the second combustion chamber # 2 is set to the open state is reduced to the first path. The first time to reach the exhaust port of the first combustion chamber # 1 via P1 and the second time to reach the exhaust port of the first combustion chamber # 1 via the second path P2 ,different. Therefore, the output torque may be reduced in the two engine speed ranges due to the exhaust pressure of the second combustion chamber. However, when the length of the first path P1 and the length of the second path P2 are set relatively long, both the first synchronous rotation speed and the second synchronous rotation speed become the normal rotation speed. It is smaller than the minimum value in several areas. For this reason, the torque does not decrease in the normal rotation speed region. When the length of the first path P1 is set to be relatively short and the length of the second path P2 is set to be relatively long, the first synchronous rotation speed falls within the normal rotation speed region. However, the second synchronous rotation speed becomes smaller than the minimum value in the normal rotation speed region. Therefore, in the normal rotation speed region, the torque reduction is limited to one rotation speed region. In general, the length of the second path P2 is such that the exhaust pressure when the exhaust port of the second combustion chamber is set to the open state is connected to the exhaust port of the first combustion chamber via the second path P2. When the arrival time and the overlap period in which the intake port and the exhaust port of the first combustion chamber are set to the open state overlap, the engine speed is smaller than the minimum value of the normally used speed range. What is necessary is just to be set so that it may become. With this configuration, it is possible to suppress a decrease in the output torque when the engine performs the operation in the normal rotation speed region, and as a result, it is possible to improve the output torque characteristics of the engine including the secondary air supply unit.
[0076]
A-1. Modification of the first embodiment
FIG. 8 is an explanatory diagram illustrating a schematic configuration of an engine 100A as a modification of the first embodiment. FIG. 8 is substantially the same as FIG. 1 except that the secondary air supply unit 200A is changed. Specifically, the secondary air pipe 220A has a zigzag passage structure in the second partial passage 222Ab in the middle stage. The zigzag passage is formed in the passage box 240.
[0077]
FIG. 9 is an explanatory diagram showing the passage box 240 of FIG. As illustrated, the passage box 240 has a substantially rectangular parallelepiped outer shape. The passage box 240 includes a passage forming portion 242 and a cover 248, and the passage forming portion 242 and the cover 248 are joined to each other. A plurality of partition plates 244 that form a zigzag passage are provided inside the passage forming portion 242. The passage forming portion 242 has passage openings 246 at both ends of the zigzag passage.
[0078]
The use of such a passage box 240 has an advantage that the volume required for disposing the secondary air supply unit can be made relatively small. Further, when such a passage box 240 is applied to an existing secondary air supply unit having a relatively short secondary air passage, the length of the secondary air passage can be relatively easily increased. There is an advantage.
[0079]
B. Second embodiment:
FIG. 10 is an explanatory diagram illustrating a schematic configuration of an engine 100B according to the second embodiment. FIG. 10 is substantially the same as FIG. 1 except that the secondary air supply unit 200B is changed. Specifically, the secondary air supply unit 200B includes a pulsation damper 250 in the middle of the secondary air pipe 220 (path P2). The pulsation damper 250 is provided in the first partial passage 222a at the middle stage, and has a function of attenuating a pressure wave propagating through the first partial passage 222a by the function of a diaphragm provided inside. .
[0080]
In this embodiment, the exhaust pressure when the exhaust port of the second combustion chamber # 2 is set to the open state reaches the exhaust port of the first combustion chamber # 1 via the pulsation damper 250. For this reason, the ultimate pressure near the exhaust port of the first combustion chamber # 1 is relatively small.
[0081]
In FIG. 10, as in the first embodiment (FIG. 1), the second path P2 is set relatively long, but when the secondary air supply unit 200B includes the pulsation damper 250, the second path P2 May be set relatively short. That is, the time when the exhaust pressure of the second combustion chamber # 2 reaches the exhaust port of the first combustion chamber # 1 via the second path P2 and the overlap period of the first combustion chamber # 1 are different. Even in the case of overlapping, the pressure when the exhaust pressure of the second combustion chamber # 2 reaches the inside of the first combustion chamber # 1 via the second path P2 can be made relatively low. Therefore, the first combustion chamber # 1 is hardly affected by the exhaust pressure of the second combustion chamber # 2. As a result, it is possible to improve the output torque characteristics of the engine including the secondary air supply unit. Become. However, as in the first embodiment, if the second path P2 is set to be relatively long, there is an advantage that a decrease in output torque can be considerably suppressed.
[0082]
In the present embodiment, the secondary air supply unit 200B includes the pulsation damper 250 in the middle of the second path P2. A buffer tank having a large space may be provided. Also in this case, the pressure wave propagating in the secondary air passage can be attenuated.
[0083]
In general, the secondary air supply unit only needs to be provided in the middle of the second path P2 and include an attenuation unit for attenuating the pressure fluctuation in the secondary air passage.
[0084]
C. Third embodiment:
FIG. 11 is an explanatory diagram illustrating a schematic configuration of an engine 100C according to the third embodiment. FIG. 11 is almost the same as FIG. 1 except that the secondary air supply unit 200C is changed. Specifically, the secondary air supply unit 200C includes a shutoff valve 260 in the middle of the secondary air pipe 220 (path P2). The shutoff valve 260 is provided in the first partial passage 222a at the middle stage, and has a function of inhibiting the propagation of the pressure wave in the first partial passage 222a.
[0085]
As described above, the secondary air supply unit 200C supplies secondary air into the partial passages 51a to 51f at the most upstream stage of the exhaust passage when the catalyst temperature is relatively low, for example, at the start of operation of the engine. The ECU 90 controls the operation of the secondary air pump 210 according to the measurement results of the temperature sensors 91 to 94 provided in each of the catalyst devices 61 to 64. When the catalyst temperature is relatively high, such as during normal operation, the ECU 90 stops the secondary air pump 210, so that no secondary air is supplied into the secondary air passage. However, even when the secondary air pump 210 is stopped, the gas in the secondary air pipe 220 can flow freely.
[0086]
Therefore, in the present embodiment, a shutoff valve 260 is provided in the middle of the secondary air pipe 220. The opening and closing operation of the shutoff valve 260 is controlled by the ECU 90. Specifically, the ECU 90 sets the shut-off valve 260 to the open state during the driving period of the secondary air pump 210 (for example, when the catalyst temperature is relatively low such as at the start of operation of the engine), and During the stop period of the air pump 210 (for example, when the catalyst temperature is relatively high during normal operation of the engine, etc.), the shut-off valve 260 is set to the closed state. When the shut-off valve 260 is set to the closed state, the pressure wave generated when the exhaust port of the second combustion chamber # 2 is set to the open state passes through the second path P2, No. 1 does not propagate to combustion chamber # 1.
[0087]
In FIG. 11, as in the first embodiment (FIG. 1), the second path P2 is set relatively long. However, when the secondary air supply unit 200C includes the shutoff valve 260, The route P2 may be set relatively short. That is, the time when the exhaust pressure of the second combustion chamber # 2 reaches the exhaust port of the first combustion chamber # 1 via the second path P2 and the overlap period of the first combustion chamber # 1 are different. Even in the case of overlapping, the exhaust pressure of the second combustion chamber # 2 can be prevented from reaching the inside of the first combustion chamber # 1 via the second path P2. Therefore, when the secondary air is not supplied into the exhaust passage, the first combustion chamber # 1 is not affected by the exhaust pressure of the second combustion chamber # 2, and as a result, the secondary air supply unit It is possible to improve the output torque characteristics of the engine including the above. However, similarly to the first embodiment, if the second path P2 is set to be relatively long, it is possible to suppress a decrease in torque even when the shutoff valve 260 is set to the open state. There are advantages. In the present embodiment, the shut-off valve 260 is always set to the open state during the driving period of the secondary air pump 210, but the driving period of the secondary air pump 210 is usually set at the time of starting the operation of the engine. Since the load on the engine is relatively small, the reduction of the output torque does not cause much problem. In other words, in the present embodiment, the shutoff valve 260 is always set to the closed state during the stop period of the secondary air pump 210, so that the decrease in the output torque during the period when the engine load is relatively large is efficiently suppressed. It is possible to do.
[0088]
In this embodiment, the ECU 90 sets the shut-off valve 260 to the open state during the driving period of the secondary air pump 210, and sets the shut-off valve 260 to the closed state during the stop period of the secondary air pump 210. I have. However, instead of this, the ECU 90 determines that the exhaust pressure of the second combustion chamber # 2 reaches the shut-off valve 260 via the first path P2, in other words, the shut-off valve whose exhaust pressure is open. The shutoff valve 260 may be set to a closed state during a period in which the passage 260 passes. In this way, during the overlap period of the first combustion chamber # 1, the exhaust pressure of the second combustion chamber # 2 does not reach the exhaust port of the first combustion chamber # 1 via the second path P2. You can do so. Alternatively, the ECU 90 may execute the above control during the driving period of the secondary air pump 210.
[0089]
C-1. Modification of the third embodiment:
FIG. 12 is an explanatory diagram illustrating a schematic configuration of an engine 100C1 as a modification of the third embodiment. FIG. 12 is substantially the same as FIG. 11 except that the secondary air supply unit 200C1 is changed. Specifically, the secondary air supply unit 200C1 includes six shut-off valves 270a to 270f in the middle of the secondary air pipe 220. The six shutoff valves 270a to 270f are provided in the six most downstream partial passages 223a to 223f, respectively, and have a function of inhibiting the propagation of the pressure wave in each of the partial passages 223a to 223f. The opening and closing operations of the shutoff valves 270a to 270f are controlled by the ECU 90. Specifically, the ECU 90 determines that the exhaust pressure when the exhaust port of the second combustion chamber # 2 is set to the open state corresponds to the first combustion chamber # 1 corresponding to the first combustion chamber # 1 via the second path P2. The first shut-off valve 270a is set to the closed state during a period in which the exhaust pressure passes through the first shut-off valve 270a in the open state during the period of reaching the shut-off valve 270a. Then, the ECU 90 sets the first shut-off valve 270a to the open state during another period. In this way, during the overlap period of the first combustion chamber # 1, the exhaust pressure of the second combustion chamber # 2 does not reach the exhaust port of the first combustion chamber # 1 via the second path P2. You can do so. This control is performed, for example, by using a map indicating the relationship between the engine speed and the opening / closing timing of the exhaust valve corresponding to each combustion chamber, or by providing a pressure sensor downstream of each of the shut-off valves 270a to 270f. Is feasible.
[0090]
In FIG. 12, as in the first embodiment (FIG. 1), the second path P2 is set relatively long, but the secondary air supply unit 200C1 is provided with shut-off valves 270a to 270f for each combustion chamber. , The second path P2 may be set relatively short. Even in this case, it is possible to prevent the exhaust pressure of the second combustion chamber # 2 from reaching the inside of the first combustion chamber # 1 via the second path P2. For this reason, the first combustion chamber is not affected by the exhaust pressure of the second combustion chamber during the overlap period, and as a result, the output torque characteristics of the engine including the secondary air supply unit can be improved. It becomes possible.
[0091]
In FIG. 12, the ECU 90 individually controls each shutoff valve provided for each combustion chamber. However, instead of this, the ECU 90 sets all the shut-off valves 270a to 270f to the open state during the driving period of the secondary air pump 210, as in FIG. All the shutoff valves 270a to 270f may be set to the closed state. Alternatively, the ECU 90 controls each shutoff valve individually during the driving period of the secondary air pump 210, and sets all the shutoff valves 270a to 270f to the closed state during the stop period of the secondary air pump 210. It may be.
[0092]
Generally, the secondary air supply section only needs to include at least one shutoff valve provided in the middle of the second path P2. The shutoff valve is preferably a valve that completely inhibits the flow of gas in the secondary air passage, but may be a valve that slightly flows gas in the closed state.
[0093]
D. Fourth embodiment:
FIG. 13 is an explanatory diagram illustrating a schematic configuration of an engine 100D according to the fourth embodiment. FIG. 13 is almost the same as FIG. 1 except that the secondary air supply unit 300D is changed. Specifically, the secondary air supply unit 300D includes two secondary air pumps 310a and 310b, and two secondary air pipes 320a and 320b connected to each secondary air pump. Each of the secondary air pipes 320a and 320b forms a secondary air passage, and the secondary air passage has a multi-stage structure in which the number of partial passages included in each stage gradually increases toward the downstream side. Specifically, one partial passage 321a connected to the first secondary air pump 310a is provided at the most upstream stage of the first secondary air pipe 320a, and at the most downstream stage, Three partial passages 322a, 322c, 322e where one partial passage 321a is branched are provided. Similarly, one partial passage 321b connected to the second secondary air pump 310b is provided at the most upstream stage of the second secondary air pipe 320b, and the one partial passage 321b is provided at the most downstream stage. Three partial passages 322b, 322d, and 322f where the partial passage 321b is branched are provided. The six most downstream partial passages 322a to 322f correspond to the six combustion chambers # 1 to # 6, respectively, and are connected to the six most upstream partial passages 51a to 51f of the exhaust passage, respectively. I have.
[0094]
In FIG. 13, the secondary air passage formed by the first secondary air pipe 320a is connected to the first, third, and fifth combustion chambers # 1, # 3, and # 5, and The secondary air passage formed by the secondary air pipe 320b is connected to the second, fourth, and sixth combustion chambers # 2, # 4, and # 6. In other words, any two combustion chambers whose combustion order is continuous (that is, combustion chamber # 1, combustion chamber # 2, combustion chamber # 2, combustion chamber # 3, combustion chamber # 3, combustion chamber # 4, combustion chamber The partial passages connected to # 4, the combustion chamber # 5, the combustion chamber # 5, the combustion chamber # 6, the combustion chamber # 6, and the combustion chamber # 1) are passages formed by other secondary air pipes 320a, 320b. There is no communication upstream. Therefore, the first combustion chamber # 1 is not affected by the exhaust pressure of the second combustion chamber # 2.
[0095]
FIG. 14 is an explanatory diagram illustrating a schematic configuration of an engine 100D1 as a first modification of the fourth embodiment. In FIG. 14, the secondary air supply unit 300D1 is changed. Specifically, the secondary air supply unit 300D1 includes three secondary air pumps 330a to 330c and three secondary air pipes 340a to 340c connected to the respective secondary air pumps. Each of the secondary air pipes 340a to 340c forms a secondary air passage, and the secondary air passage has a multi-stage structure in which the number of partial passages included in each stage gradually increases toward the downstream side. Specifically, one partial passage 341a connected to the first secondary air pump 330a is provided at the most upstream stage of the first secondary air pipe 340a. There are provided two partial passages 342a and 342d where one partial passage 341a is branched. Similarly, at the most upstream stage of the second secondary air pipe 340b, one partial passage 341b connected to the second secondary air pump 330b is provided, and at the most downstream stage, the one partial passage 341b is provided. Two partial passages 342b and 342e that branch off from the partial passage 341b are provided. Further, at the most upstream stage of the third secondary air pipe 340c, one partial passage 341c connected to the third secondary air pump 330c is provided, and at the most downstream stage, the one partial passage 341c is provided. Two partial passages 342c and 342f where the passage 341c is branched are provided. The six most downstream partial passages 342a to 342f correspond to the six combustion chambers # 1 to # 6, respectively, and are respectively connected to the six most upstream partial passages 51a to 51f of the exhaust passage. I have.
[0096]
In FIG. 14, the secondary air passage formed by the first secondary air pipe 340a is connected to the first and fourth combustion chambers # 1 and # 4. The secondary air passage formed by the second secondary air pipe 340b is connected to the second and fifth combustion chambers # 2 and # 5, and the secondary air passage formed by the third secondary air pipe 340c. The next air passage is connected to the third and sixth combustion chambers # 3 and # 6. In other words, the partial passages connected to any two combustion chambers in which the combustion order is continuous are passages formed by the other secondary air pipes 340a to 340c, and are not connected on the upstream side. Therefore, the first combustion chamber # 1 is not affected by the exhaust pressure of the second combustion chamber # 2.
[0097]
FIG. 15 is an explanatory diagram illustrating a schematic configuration of an engine 100D2 as a second modification of the fourth embodiment. In FIG. 15, the secondary air supply unit 300D2 is changed. Specifically, the secondary air supply unit 300D2 includes six secondary air pumps 350a to 350f and six secondary air pipes 360a to 360f connected to the respective secondary air pumps.
[0098]
In FIG. 15, the secondary air passages formed by the secondary air pipes 360a to 360f are respectively connected to one combustion chamber # 1 to # 6. In other words, the secondary air passage connected to any two combustion chambers in which the combustion order is continuous is a passage formed by other secondary air pipes 360a to 360f, and is not connected on the upstream side. More specifically, each combustion chamber does not communicate with any other combustion chamber via a path through the secondary air passage. Therefore, each combustion chamber is not affected by the exhaust pressure of the other combustion chambers.
[0099]
As described above, in the engine of the present embodiment, the plurality of combustion chambers # 1 to # 6 are divided into a plurality of groups. The secondary air supply unit includes, for each group, a secondary air pump and a secondary air passage connected to the secondary air pump. The first and second combustion chambers # 1 and # 2 in which the combustion order is continuous among the plurality of combustion chambers belong to different groups. By employing this configuration, even when both the exhaust port of the first combustion chamber and the exhaust port of the second combustion chamber # 2 are set to the open state, the first combustion chamber # 1 and the second combustion chamber # 2 are not opened. Does not communicate with the combustion chamber # 2 through a path passing through the secondary air passage. Therefore, it is possible to improve the output torque characteristics of the engine including the secondary air supply unit.
[0100]
The present invention is not limited to the above-described examples and embodiments, but can be implemented in various modes without departing from the gist of the invention, and for example, the following modifications are possible.
[0101]
(1) In the first embodiment (FIG. 1), the lengths of the first and second paths P1 and P2 are set in a rotational speed region where the first and second synchronous rotational speeds are normally used (a normal rotational speed region). ) Is set to be smaller than the minimum value. Incidentally, the minimum value in the normal rotation speed region depends on the usage environment of the engine. That is, when the engine can be used with no load, such as when mounted on a vehicle or a ship, the minimum value of the normal rotation speed region is preferably set to the idle rotation speed. Also, when the engine is used with a substantially constant load, such as when mounted on a stationary system, the minimum value in the normal rotation speed region is set to the minimum value in the rotation speed region that is used regularly. Preferably, it is set. As can be understood from this description, the lengths of the first and second paths P1 and P2 are set so as to match the rotation speeds at which the first and second synchronization rotation speeds are hardly used. Is preferred.
[0102]
(2) In the above embodiment, the ECU 90 controls the operation of the secondary air pump based on the measurement results of the temperature sensors 91 to 94, but the temperature sensor can be omitted. In this case, for example, the operation of the secondary air pump may be stopped after a lapse of a predetermined period from the operation start time of the engine.
[0103]
(3) In the above embodiment, the four catalyst devices 61 to 64 are provided in the exhaust passage, but a smaller or larger number of catalyst devices may be provided. Further, in the above embodiment, the catalyst device is provided in each of the two partial passages 52a and 52b in the middle stage, but is instead provided in each of the six partial passages 51a to 51f in the most upstream stage. And may be provided in one of the partial passages 53 at the most downstream stage. Generally, at least one catalyst device for purifying exhaust gas may be provided in the exhaust passage.
[0104]
In the above embodiment, the catalyst device is provided in the exhaust passage, but the catalyst device can be omitted. Also in this case, by using the secondary air supply unit, the unburned fuel in the exhaust gas is burned, and as a result, a part of the harmful components in the exhaust gas can be reduced.
[0105]
(4) In the first to third embodiments, the secondary air pipe 220 is provided in the exhaust port 32 so that the secondary air blows out toward the combustion chamber. May be provided so as to blow out toward the downstream side of the exhaust passage. By doing so, the pressure when the exhaust pressure of the second combustion chamber # 2 reaches the exhaust port of the first combustion chamber # 1 via the second path P2 can be made relatively small.
[0106]
Further, in the above embodiment, as shown in FIG. 2, the secondary air pipe 220 is inserted into the exhaust port 32 of each combustion chamber, but a part of the secondary air passage formed by the secondary air pipe is , May be formed inside the cylinder head 30.
[0107]
(5) In the first to third embodiments, the secondary air supply unit supplies the secondary air into the partial passages 51a to 51f at the most upstream stage constituting the exhaust passage, but supplies the secondary air to other parts. The next air may be supplied. For example, the secondary air supply unit may supply the secondary air into the two middle passages 52a and 52b that constitute the exhaust passage. Even in this case, the unburned fuel in the exhaust gas can be burned. In this case, the secondary air supply section may have a secondary air passage including two partial passages at the most downstream stage. However, according to the above-described embodiment, since the secondary air can be supplied into the exhaust gas having a relatively high temperature, there is an advantage that the unburned fuel in the exhaust gas can be efficiently burned. .
[0108]
Generally, a secondary air supply unit for supplying secondary air into the exhaust passage is a secondary air supply source and a secondary air passage connected to the secondary air supply source, and includes a branch on the upstream side. And a secondary air passage including a plurality of partial secondary air passages that communicate with each other via a point.
[0109]
(6) In the above embodiment, the engine has six combustion chambers, but may have fewer or more combustion chambers. However, the deterioration of the output torque characteristic is likely to occur when the engine has three or more combustion chambers. Therefore, the effect of the present invention is remarkable when the engine includes three or more combustion chambers.
[0110]
Further, in the above embodiment, the V-type engine has been described, but the present invention is also applicable to an in-line type engine.
[0111]
Further, in the above-described embodiment, a gasoline engine has been described, but the present invention is also applicable to a diesel engine.
[0112]
Generally, the present invention is applicable to an internal combustion engine having a plurality of combustion chambers.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating a schematic configuration of a gasoline engine 100 according to a first embodiment.
FIG. 2 is an explanatory diagram schematically showing an internal configuration of an engine body 10 of FIG.
FIG. 3 is an explanatory diagram schematically showing operation strokes of six combustion chambers # 1 to # 6 in FIG. 1;
FIG. 4 is a graph showing a relationship between an engine speed and an output torque when the length of an exhaust pipe 50 is changed.
FIG. 5 is an explanatory diagram showing exhaust pulsation at an engine speed n of FIG. 4;
FIG. 6 is a graph showing the relationship between the engine speed and the output torque when the length of the secondary air pipe 220 is changed, and corresponds to FIG.
7 is an explanatory view showing exhaust pulsation at an engine speed n of FIG. 6, and corresponds to FIG. 5;
FIG. 8 is an explanatory diagram showing a schematic configuration of an engine 100A as a modification of the first embodiment.
FIG. 9 is an explanatory view showing the passage box 240 of FIG.
FIG. 10 is an explanatory diagram illustrating a schematic configuration of an engine 100B according to a second embodiment.
FIG. 11 is an explanatory diagram showing a schematic configuration of an engine 100C in a third embodiment.
FIG. 12 is an explanatory diagram showing a schematic configuration of an engine 100C1 as a modified example of the third embodiment.
FIG. 13 is an explanatory diagram illustrating a schematic configuration of an engine 100D according to a fourth embodiment.
FIG. 14 is an explanatory diagram showing a schematic configuration of an engine 100D1 as a first modification of the fourth embodiment.
FIG. 15 is an explanatory diagram showing a schematic configuration of an engine 100D2 as a second modification of the fourth embodiment.
[Explanation of symbols]
10 Engine body
20 ... Cylinder block
22 ... cylinder
24 ... Crankcase
26 ... Piston
27… Connecting rod
28 ... Crankshaft
30 ... Cylinder head
31 ... intake port
32 ... Exhaust port
33 ... intake valve
34 ... exhaust valve
36 ... Spark plug
40 ... intake pipe
41 ... Partial passage
42a to 42f: partial passage
46 ... Throttle valve
48: Fuel injection unit
50 ... exhaust pipe
51a to 51f: partial passage
52a, 52b ... partial passage
53 ... Partial passage
61, 62... Second catalyst device
61, 62... Fourth catalyst device
61 to 64: Catalyst device
90 ... ECU
91 to 94 ... Temperature sensor
100 ... engine
200: Secondary air supply unit
210 ... Secondary air pump
220 ... secondary air pipe
221 ... partial passage
222a, 222b ... partial passage
223a to 223f: partial passage
240 ... aisle box
242 ... passage forming part
244 ... Partition plate
246 ... passage entrance
248 ... Lid
250 ... pulsation damper
260 ... shut-off valve
270a to 270f ... shut-off valve
300D: Secondary air supply unit
310a, 310b ... secondary air pump
320a, 320b ... secondary air pipe
321a, 321b ... partial passage
322a to 322f: partial passage
330a-330c ... secondary air pump
340a-340c ... secondary air pipe
341a, 341b, 341c ... partial passage
342a to 342f: partial passage
350a-350f ... secondary air pump
360a to 360f ... secondary air pipe
N1 ... Meeting point
N2 ... Branch point
P1 ... First path
P2: Second path

Claims (11)

  1. An internal combustion engine,
    Multiple combustion chambers,
    An exhaust passage through which exhaust gas discharged from the plurality of combustion chambers passes, the exhaust passage including a plurality of partial exhaust passages connected to the plurality of combustion chambers and communicating with each other via a downstream junction; ,
    A secondary air supply unit for supplying secondary air into the exhaust passage,
    With
    The secondary air supply unit,
    A secondary air supply,
    A secondary air passage connected to the secondary air supply source, the secondary air passage including a plurality of partial secondary air passages communicating with each other via an upstream branch point,
    With
    In any of the first and second combustion chambers in which the combustion order is continuous among the plurality of combustion chambers, both the exhaust port of the first combustion chamber and the exhaust port of the second combustion chamber are open. When set to, while communicating via a first path including the junction, and communicating via a second path including the branch point,
    The internal combustion engine according to claim 1, wherein a length of the second path is set substantially equal to a length of the first path.
  2. The internal combustion engine according to claim 1,
    The plurality of partial secondary air passages correspond to each of the plurality of combustion chambers,
    The internal combustion engine, wherein each of the partial secondary air passages supplies secondary air into each of the partial exhaust passages.
  3. The internal combustion engine according to claim 1,
    The length of the second path is such that the exhaust pressure when the exhaust port of the second combustion chamber is set to the open state reaches the exhaust port of the first combustion chamber via the second path. And the overlap period during which the intake port and the exhaust port of the first combustion chamber are set to the open state, the rotational speed of the internal combustion engine is the minimum value of the normally used rotational speed region. An internal combustion engine that is set to be smaller.
  4. An internal combustion engine,
    Multiple combustion chambers,
    An exhaust passage through which exhaust gas discharged from the plurality of combustion chambers passes;
    A secondary air supply unit for supplying secondary air into the exhaust passage,
    With
    The secondary air supply unit,
    A secondary air supply,
    A secondary air passage connected to the secondary air supply source, the secondary air passage including a plurality of partial secondary air passages communicating with each other via an upstream branch point,
    With
    In any of the first and second combustion chambers in which the combustion order is continuous among the plurality of combustion chambers, both the exhaust port of the first combustion chamber and the exhaust port of the second combustion chamber are open. When set to, communication via the path including the branch point,
    The length of the path is determined by the time when the exhaust pressure when the exhaust port of the second combustion chamber is set to the open state reaches the exhaust port of the first combustion chamber via the path, and The overlap period in which the intake port and the exhaust port of the first combustion chamber are set to the open state and the rotation speed of the internal combustion engine when the overlap period overlaps is smaller than the minimum value of the normally used rotation speed region. An internal combustion engine characterized by being set.
  5. The internal combustion engine according to claim 4, wherein
    The exhaust passage includes a plurality of partial exhaust passages respectively connected to the plurality of combustion chambers,
    The plurality of partial secondary air passages correspond to each of the plurality of combustion chambers,
    The internal combustion engine, wherein each of the partial secondary air passages supplies secondary air into each of the partial exhaust passages.
  6. An internal combustion engine,
    Multiple combustion chambers,
    An exhaust passage through which exhaust gas discharged from the plurality of combustion chambers passes;
    A secondary air supply unit for supplying secondary air into the exhaust passage,
    With
    The secondary air supply unit,
    A secondary air supply,
    A secondary air passage connected to the secondary air supply source, the secondary air passage including a plurality of partial secondary air passages communicating with each other via an upstream branch point,
    With
    In any of the first and second combustion chambers in which the combustion order is continuous among the plurality of combustion chambers, both the exhaust port of the first combustion chamber and the exhaust port of the second combustion chamber are open. When set to, communication via the path including the branch point,
    The secondary air supply unit further includes:
    An internal combustion engine provided with an attenuator provided in the middle of the path, for attenuating pressure fluctuations in the secondary air passage.
  7. An internal combustion engine,
    Multiple combustion chambers,
    An exhaust passage through which exhaust gas discharged from the plurality of combustion chambers passes;
    A secondary air supply unit for supplying secondary air into the exhaust passage,
    With
    The secondary air supply unit,
    A secondary air supply,
    A secondary air passage connected to the secondary air supply source, the secondary air passage including a plurality of partial secondary air passages communicating with each other via an upstream branch point,
    With
    In any of the first and second combustion chambers in which the combustion order is continuous among the plurality of combustion chambers, both the exhaust port of the first combustion chamber and the exhaust port of the second combustion chamber are open. When set to, communication via the path including the branch point,
    The secondary air supply unit further includes:
    Comprising a shut-off valve provided in the middle of the path,
    The internal combustion engine further comprises:
    A control unit for controlling the operation of the shut-off valve,
    The control unit sets the shut-off valve to an open state during a driving period of the secondary air supply source, and sets the shut-off valve to a closed state during a stop period of the secondary air supply source. Features internal combustion engine.
  8. An internal combustion engine,
    Multiple combustion chambers,
    An exhaust passage through which exhaust gas discharged from the plurality of combustion chambers passes;
    A secondary air supply unit for supplying secondary air into the exhaust passage,
    With
    The secondary air supply unit,
    A secondary air supply,
    A secondary air passage connected to the secondary air supply source, the secondary air passage including a plurality of partial secondary air passages communicating with each other via an upstream branch point and corresponding to each of the plurality of combustion chambers. A secondary air passage;
    With
    In any of the first and second combustion chambers in which the combustion order is continuous among the plurality of combustion chambers, both the exhaust port of the first combustion chamber and the exhaust port of the second combustion chamber are open. When set to, communication via the path including the branch point,
    The secondary air supply unit further includes:
    Comprising a plurality of the shut-off valves provided in each of the plurality of partial secondary air passages,
    The internal combustion engine further comprises:
    A control unit for controlling the operation of the plurality of shut-off valves,
    The control unit may be configured to control the exhaust pressure when the exhaust port of the second combustion chamber is set to the open state to reach the first shutoff valve corresponding to the first combustion chamber via the path. An internal combustion engine, wherein the first shutoff valve is set to a closed state.
  9. An internal combustion engine,
    Multiple combustion chambers,
    An exhaust passage through which exhaust gas discharged from the plurality of combustion chambers passes;
    A secondary air supply unit for supplying secondary air into the exhaust passage,
    With
    The plurality of combustion chambers are divided into a plurality of groups,
    The secondary air supply unit, for each of the groups,
    A secondary air supply,
    A secondary air passage connected to the secondary air supply,
    With
    An internal combustion engine according to claim 1, wherein any of the first and second combustion chambers in which the combustion order is continuous among the plurality of combustion chambers belongs to different groups.
  10. The internal combustion engine according to claim 9, wherein
    An internal combustion engine, wherein the number of the plurality of combustion chambers is equal to the number of the plurality of groups.
  11. The internal combustion engine according to any one of claims 1, 4, 6, 7, 8, and 9, further comprising:
    An internal combustion engine including a catalyst device provided in the exhaust passage for purifying exhaust gas.
JP2002220657A 2002-07-30 2002-07-30 Internal combustion engine Pending JP2004060546A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2002220657A JP2004060546A (en) 2002-07-30 2002-07-30 Internal combustion engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2002220657A JP2004060546A (en) 2002-07-30 2002-07-30 Internal combustion engine

Publications (1)

Publication Number Publication Date
JP2004060546A true JP2004060546A (en) 2004-02-26

Family

ID=31941184

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2002220657A Pending JP2004060546A (en) 2002-07-30 2002-07-30 Internal combustion engine

Country Status (1)

Country Link
JP (1) JP2004060546A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4954708B2 (en) * 2004-10-20 2012-06-20 耕一 畑村 engine

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4954708B2 (en) * 2004-10-20 2012-06-20 耕一 畑村 engine

Similar Documents

Publication Publication Date Title
US9506396B2 (en) Twin scroll turbocharger with EGR takeoffs
US9624823B2 (en) Internal combustion engine with deactivatable cylinder, and method for operating an internal combustion engine of said type
US5562086A (en) Control device of a varable cylinder engine
US6550240B2 (en) Lean engine control with multiple catalysts
US6971343B2 (en) Spark-ignition engine controller
USRE39506E1 (en) Crankcase scavenged two-stroke engines
US8671920B2 (en) Internal combustion engine
US6877464B2 (en) Spark-ignition engine controller
US4829941A (en) Intake system for multiple-cylinder engine
US4679531A (en) Intake system for internal combustion engine
RU2663604C2 (en) Method (versions) and system of selective withdrawal from operation of one or more engine cylinders
JP4215085B2 (en) Internal combustion engine
EP1403490B1 (en) Control unit for spark ignition-type engine
US7299787B2 (en) Internal combustion engine intake device
KR950000600B1 (en) Turbo-charger attached engine
DE102011104996A1 (en) Diesel engine and method for regulating bzw. control of the diesel engine
US5239960A (en) Engine induction system provided with a mechanical supercharger
US9316165B2 (en) Method for exhaust gas recirculation rate control
EP1945932B1 (en) An exhaust gas recirculation system
US7246595B1 (en) Diesel engine with differential cylinder group operation
JP5365531B2 (en) Control device for internal combustion engine
US8359836B2 (en) Internal combustion engine, vehicle, marine vessel, and secondary air supply method for internal combustion engine
DE102011105110B4 (en) Diesel engine for a vehicle
US7753037B2 (en) Engine
EP1712760B1 (en) Indirect variable valve actuation for an internal combustion engine