WO2020229860A1 - Moteur à combustion interne - Google Patents

Moteur à combustion interne Download PDF

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Publication number
WO2020229860A1
WO2020229860A1 PCT/IB2019/000534 IB2019000534W WO2020229860A1 WO 2020229860 A1 WO2020229860 A1 WO 2020229860A1 IB 2019000534 W IB2019000534 W IB 2019000534W WO 2020229860 A1 WO2020229860 A1 WO 2020229860A1
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WO
WIPO (PCT)
Prior art keywords
intake
dead center
internal combustion
combustion engine
center
Prior art date
Application number
PCT/IB2019/000534
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English (en)
Japanese (ja)
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WO2020229860A8 (fr
Inventor
理晴 葛西
鈴木　琢磨
チヤータジ アクス
Original Assignee
日産自動車株式会社
ルノー エス．ア．エス
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.)
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Publication date
Application filed by 日産自動車株式会社, ルノー エス．ア．エス filed Critical 日産自動車株式会社
Priority to PCT/IB2019/000534 priority Critical patent/WO2020229860A1/fr
Priority to JP2021519011A priority patent/JP7151882B2/ja
Publication of WO2020229860A1 publication Critical patent/WO2020229860A1/fr
Publication of WO2020229860A8 publication Critical patent/WO2020229860A8/fr

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
    • F01L1/344—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
    • F01L1/356—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear making the angular relationship oscillate, e.g. non-homokinetic drive
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D15/00—Varying compression ratio
    • F02D15/02—Varying compression ratio by alteration or displacement of piston stroke

Definitions

  • the present invention relates to a spark-ignition internal combustion engine that injects fuel into a cylinder to perform lean burn.
  • Lean burn which burns with a dilute mixture, is known as one means of improving the fuel consumption rate of spark-ignition internal combustion engines represented by gasoline engines for vehicles.
  • Lean burn which is effective in improving the fuel consumption rate, can be realized not only by setting the air-fuel ratio, which is the ratio of fresh air to the amount of fuel, to be larger than the theoretical air-fuel ratio, but also by a large amount of exhaust gas return.
  • air-fuel ratio which is the ratio of fresh air to the amount of fuel
  • Patent Document 1 discloses a valve gear that changes the profile of the cam in the linear motion valve mechanism so that the maximum lift time is biased to the advance angle side or the retard angle side.
  • Patent Document 2 relates to a double-link piston crank mechanism in which a piston and a crank pin are connected by a plurality of links.
  • a piston in a stroke is set according to a setting of a link geometry. It discloses that the characteristics of speed can be set appropriately.
  • An object of the present invention is to effectively utilize these technologies to strengthen gas flow such as tumble in a cylinder and to stabilize combustion of lean combustion.
  • the spark ignition type internal combustion engine according to the present invention
  • the double-link piston crank mechanism is configured so that the peak of the piston speed in the intake stroke is located on the lagging side of the half crank angle position between the intake top dead center and the intake bottom dead center.
  • the lift characteristics of the intake valve are asymmetrical between the ascending section and the descending section, and the center of gravity of the integrated lift amount is located on the lagging side of the center of the intake valve operating angle.
  • FIG. 6 is a configuration explanatory view schematically showing a configuration of an internal combustion engine according to the present invention.
  • FIG. 1 schematically shows the configuration of an internal combustion engine 1 for an automobile to which the present invention is applied.
  • the internal combustion engine 1 is a 4-stroke cycle in-cylinder direct-injection spark-ignition internal combustion engine equipped with a double-link piston crank mechanism 2, and basically performs lean combustion that is leaner than the stoichiometric air-fuel ratio.
  • a pair of intake valves 4 and a pair of exhaust valves 5 are arranged on the ceiling wall surface of each cylinder 3, and a spark plug 6 is arranged in a central portion surrounded by these intake valves 4 and exhaust valves 5.
  • the combustion chamber 13 has a general pent roof type, and the intake port 15 and the exhaust port 17 extend so as to face each other.
  • the intake valve 4 is opened and closed via a valve operating mechanism (not shown), and has a lift characteristic that is asymmetrical between the ascending section and the descending section, as will be described later.
  • the exhaust valve 5 is also opened and closed via a valve operating mechanism (not shown).
  • the lift characteristic of the exhaust valve 5 is set to, for example, a general characteristic that opens before the bottom dead center of the piston and closes after the top dead center of the piston.
  • valve operating mechanism of the intake valve 4 and the exhaust valve 5 a direct acting valve mechanism in which the cam directly presses the cylindrical tappet provided at the valve stem end, and the cam lift is attached to the valve stem via the rocker arm.
  • Known valve operating mechanisms such as a rocker arm type valve operating mechanism that transmits, a hydraulic valve operating mechanism that opens and closes valves 4 and 5 by hydraulic pressure, and an electromagnetic valve operating mechanism that opens and closes valves 4 and 5 using a solenoid are appropriately provided. Can be used.
  • the lift characteristic of the intake valve 4 is a high lift type characteristic in which the lift amount is large compared to the operating angle
  • a rocker arm type valve operating mechanism, particularly a cam which can obtain a lift amount expansion action by the lever ratio.
  • a roller rocker arm type valve operating mechanism with reduced frictional resistance with the intake valve 4 is used to drive the intake valve 4.
  • Both the intake valve 4 and the exhaust valve 5 can be combined with a variable valve timing mechanism that can change the opening time and closing time.
  • Each cylinder 3 is provided with a fuel injection valve 16 so as to inject fuel directly into the cylinder.
  • the fuel injection valve 16 is located below the pair of intake ports 15, and is configured to inject fuel diagonally downward.
  • fuel injection is generally performed from the fuel injection valve 16 in the latter half of the compression stroke, and the stratified air-fuel mixture is ignited.
  • an auxiliary fuel injection valve 12 is provided at each of the intake ports 15 of each cylinder.
  • the auxiliary fuel injection valve 12 is configured so that fuel can be injected toward the intake valve 4 in the intake port 15. For example, at the time of homogeneous combustion with the target air-fuel ratio as the stoichiometric air-fuel ratio, a part or all of the fuel is injected and supplied by the auxiliary fuel injection valve 12. Alternatively, a part of the fuel is supplied from the auxiliary fuel injection valve 12 at the time of high load when the total fuel amount becomes large.
  • the configuration including the auxiliary fuel injection valve 12 is not essential, and the configuration may include only the fuel injection valve 16 for in-cylinder fuel injection.
  • An electronically controlled throttle valve 19 whose opening degree is controlled by a control signal from an engine controller (not shown) is interposed upstream of the intake collector 18 of the intake passage 14, and further upstream of the electronically controlled throttle valve 19. , An air flow meter 20 for detecting the amount of intake air and an air cleaner 21 are arranged.
  • a catalyst device 26 made of an appropriate catalyst is arranged in the exhaust passage 25 where the plurality of exhaust ports 17 are merged.
  • the catalyst device 26 is configured to include, for example, a NOx storage catalyst and a three-way catalyst.
  • An air-fuel ratio sensor 28 for detecting the air-fuel ratio is arranged on the upstream side of the catalyst device 26.
  • the double-link type piston crank mechanism 2 utilizes a known configuration described in Patent Document 2 and the like, and includes a lower link 42 rotatably supported by a crank pin 41a of a crankshaft 41 and the lower link 42.
  • the upper link 45 that connects the upper pin 43 at one end of the piston pin 43 and the piston pin 44a of the piston 44 to each other, the control link 47 whose one end is connected to the control pin 46 at the other end of the lower link 42, and the control link 47. It is mainly composed of a control shaft 48 that swingably supports the other end.
  • the crankshaft 41 and the control shaft 48 are rotatably supported in the crankcase 49a below the cylinder block 49.
  • the control shaft 48 has an eccentric shaft portion 48a whose position changes with the rotation of the control shaft 48, and the end portion of the control link 47 is rotatably fitted to the eccentric shaft portion 48a. It fits. That is, the double-link type piston crank mechanism 2 of the illustrated example is configured as a variable compression ratio mechanism capable of changing the mechanical compression ratio of the internal combustion engine 1, and the piston 44 dies as the control shaft 48 rotates. The point position is displaced up and down, thus changing the mechanical compression ratio.
  • an electric actuator 51 having a rotation center axis parallel to the crankshaft 41 is arranged on the outer wall surface of the crankcase 49a.
  • the electric actuator 51 and the control shaft are routed via a first arm 52 fixed to the output rotation shaft of the electric actuator 51, a second arm 53 fixed to the control shaft 48, and an intermediate link 54 connecting the two. It is linked with 48.
  • the electric actuator 51 includes an electric motor and a transmission mechanism arranged in series in the axial direction.
  • the electric actuator 51 is controlled by a control signal from an engine controller (not shown) so as to realize a target compression ratio according to the engine operating conditions.
  • the target compression ratio is basically a high compression ratio on the low load side, and the higher the load, the lower the compression ratio for knocking suppression and the like. In one embodiment, the target compression ratio is set stepwise.
  • the peak of the piston speed in the intake stroke is on the latter half of the intake stroke, that is, on the side behind the crank angle position of 1/2 between the intake top dead center and the intake bottom dead center.
  • the link geometry is set to be located at. In other words, assuming that the crank angle between the intake top dead center and the intake bottom dead center is 180 °, the peak of the piston speed exists on the lagging side of 90 ° CA after the top dead center. If the crank angle between the intake top dead center and the intake bottom dead center is 176 °, the peak of the piston speed exists on the lagging side of 88 ° CA after the top dead center, which is 1/2.
  • the crankshaft 41 rotates in the counterclockwise direction in FIG.
  • top dead center and bottom dead center are not the position of the crank pin 41a, but the piston top dead center where the movement direction of the piston 44 is reversed and the piston top dead center. It means the bottom dead center of the piston.
  • the distance between the top dead center and the bottom dead center is correctly 180 ° each in the crank angle between the ascending stroke and the descending stroke, whereas the double link type piston crank mechanism 2 In, the distance is not completely 180 °, but is slightly (for example, about several °).
  • the distance indicated by the crank angle between the top dead center and the bottom dead center is not completely 180 °, and the ascending stroke and the descending stroke are equal to 180. Even if it is regarded as ° CA, there is no difference in terms of action and effect.
  • the mechanical compression ratio of the internal combustion engine 1 can be changed within a certain range (for example, 10 to 15), and the link can be changed accordingly.
  • the geometry changes, but in one preferred embodiment, the peak piston speed is located late in the intake stroke under all controllable compression ratio control positions.
  • the link geometry may be such that the peak of the piston speed is located in the latter half of the intake stroke at the maximum compression ratio within the controllable range.
  • FIG. 2 is a characteristic diagram showing the lift characteristics and the piston speed characteristics of the intake valve 4 in comparison with the examples and the comparative examples.
  • the leftmost “TDC” is the intake top dead center
  • the “BDC” is the intake bottom dead center
  • the rightmost “TDC” is the compression top dead center.
  • the "intake stroke” is between the intake top dead center and the intake bottom dead center. As mentioned above, the distance between the top dead center and the bottom dead center (that is, the intake stroke) is not strictly 180 ° CA.
  • Line a shows the change in piston speed in the embodiment.
  • the peak of the piston speed in the descending stroke is the crank angle position of 1/2 between the latter half of the intake stroke, that is, the intake top dead center and the intake bottom dead center. It is located on the lagging side. In the illustrated example, it has a peak near 120 ° CA after the inspiratory top dead center.
  • Line b shows the lift characteristics of the intake valve 4 of the embodiment.
  • the lift characteristics of the intake valve 4 of the embodiment are asymmetrical between the ascending section and the descending section, and the point where the maximum lift is obtained is the center of the operating angle (crank angle between the opening time and the closing time). It is biased to the lagging side. Due to such an asymmetrical lift characteristic, the center of gravity G of the integrated lift amount is located on the lagging side of the center of the intake valve operating angle. In the illustrated example, the center of gravity G is located in the latter half of the intake stroke defined by the intake top dead center and the intake bottom dead center.
  • the closing time is set near the inspiratory bottom dead center. For example, it is within a range of about ⁇ 5 ° CA with respect to bottom dead center.
  • the opening time is set near the intake top dead center (for example, within ⁇ 5 ° CA).
  • the operating angle can be set as appropriate, but in the illustrated example, it has an operating angle of about 180 ° CA.
  • the distance between the top dead center and the bottom dead center is not strictly 180 ° CA, so the lift characteristic (opening / closing timing) of the intake valve 4 is set in consideration of this.
  • Line c shows the piston speed in the case of a single link type piston crank mechanism as a comparative example.
  • the peak of the piston speed in the descending stroke is located in the first half of the intake stroke.
  • Line d shows the lift characteristics of the intake valve of the comparative example, and shows the general lift characteristics that are symmetrical between the ascending section and the descending section.
  • the point of maximum lift is at the center of the operating angle
  • the center of gravity of the integrated lift amount is also located at the center of the operating angle.
  • the opening time and the closing time of the intake valve are shown to be the same as those in the embodiment.
  • FIG. 3 is a characteristic diagram showing the lift characteristics (line d) of the intake valve and the piston speed characteristics (line c) in such a comparative example.
  • the distance between the top dead center and the bottom dead center is 180 ° CA.
  • FIG. 4 is an explanatory diagram of the principle of tumble generation in the cylinder.
  • the intake flow flows from the intake port 15 into the cylinder at high speed through the opening of the intake valve 4.
  • This high-speed intake flow creates a vertical swirling flow, or tumble, in the cylinder.
  • the strength of this tumble correlates with the descending speed of the piston 44 and the opening area of the intake valve 4, that is, the lift amount. If the intake valve 4 is greatly lifted when the piston speed is high, a large amount of intake flow flows in at high speed through the opening of the intake valve 4, so that a strong tumble can be obtained.
  • the tumble generated in the intake stroke remains until the compression stroke, promotes lean burn by the fuel injected into the cylinder in the latter half of the compression stroke, and contributes to the stabilization of lean burn.
  • the peak of the piston speed in the downward direction is in the first half of the intake stroke, and the point where the maximum lift is reached and the center of gravity of the integrated lift amount are at the center of the operating angle.
  • the timing when the strongest occurs is relatively early in the inspiratory stroke. In the latter half of the intake stroke, the piston speed becomes low and the lift amount of the intake valve also becomes small, so that the flow velocity and the flow rate of the intake flow flowing in through the opening of the intake valve sharply decrease. Therefore, the tumble generated in the cylinder is weak, and in particular, since the timing at which the tumble is strongly generated is early, it is difficult to leave a tumble of sufficient strength until the latter half of the compression stroke.
  • the point at which the intake valve 4 becomes the maximum lift and the center of gravity G of the integrated lift amount are offset to the lag side in the operating angle, and this Since the peak of the piston speed in the downward direction is located on the lagging side in the intake stroke, the timing at which the tumble occurs most strongly is the latter half of the intake stroke. Further, even at the time when the intake bottom dead center is approached, the lift amount (line b) of the intake valve 4 is larger than the lift amount (line d) of the comparative example, and the piston speed (line a) is also the piston speed (line a) of the comparative example. Since it is higher than the line c), the tumble continues to be generated relatively strongly. Therefore, the tumble generated in the cylinder becomes stronger, and in particular, the timing at which the tumble is strongly generated becomes stronger, so that a tumble having sufficient strength can be left until the latter half of the compression stroke.
  • the peak of the piston speed and the position of the center of gravity G of the integrated lift amount of the intake valve 4 are not so far apart.
  • the peak of the piston speed and the center of gravity G of the integrated lift amount of the intake valve 4 are located within a range of 10 ° in terms of crank angle. That is, it is desirable that the center of gravity G of the integrated lift amount is located within the range of ⁇ 10 ° CA with respect to the peak of the piston speed.
  • the intake valve closing time is set to near the bottom dead center in the configuration of the comparative example, the lift amount decreases early in the latter half of the intake stroke, so it is difficult to generate a sufficient tumble. Therefore, it is not possible to advance the intake valve closing time while ensuring sufficient tumble.
  • the center of gravity G of the integrated lift amount is offset to the side delayed from the center of the operating angle, and the peak of the piston speed is similarly delayed to the latter half of the intake stroke to accelerate the closing time of the intake valve 4.
  • lean combustion can be achieved by strengthening the tumble to improve the fuel consumption rate, and at the same time, knocking can be suppressed.
  • variable compression ratio mechanism is not essential in the present invention, and the double-link piston whose mechanical compression ratio does not change is not essential. It may be a crank mechanism.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Combustion Methods Of Internal-Combustion Engines (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)

Abstract

La présente invention concerne un moteur à combustion interne à allumage par étincelle (1) pourvu d'une soupape d'injection de carburant (16) pour injecter un carburant dans un cylindre et qui effectue une combustion maigre. Ce moteur à combustion interne (1) est pourvu d'un mécanisme de manivelle à piston de type à double liaison (2). La géométrie de liaison du mécanisme de manivelle à piston de type à double liaison (2) est configurée de telle sorte que le pic de la vitesse de piston (ligne a) dans une course d'admission est positionné davantage vers un côté de retard qu'une position d'1/2 angle de manivelle entre le point mort haut d'admission (TDC) et le point mort bas d'admission (BDC). La caractéristique de levage (ligne b) d'une soupape d'admission (4) est asymétrique dans une section ascendante et dans une section descendante et le centre de gravité (G) de la quantité de levage accumulée est positionné davantage vers un côté de retard que le centre de l'angle de fonctionnement de soupape d'admission. En conséquence, la force de culbutage est améliorée dans la dernière moitié de la course d'admission.
PCT/IB2019/000534 2019-05-13 2019-05-13 Moteur à combustion interne WO2020229860A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/IB2019/000534 WO2020229860A1 (fr) 2019-05-13 2019-05-13 Moteur à combustion interne
JP2021519011A JP7151882B2 (ja) 2019-05-13 2019-05-13 内燃機関

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/IB2019/000534 WO2020229860A1 (fr) 2019-05-13 2019-05-13 Moteur à combustion interne

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WO2020229860A1 true WO2020229860A1 (fr) 2020-11-19
WO2020229860A8 WO2020229860A8 (fr) 2021-09-10

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS638632B2 (fr) * 1982-11-02 1988-02-23 Matsushita Electronics Corp
JP2002285857A (ja) * 2001-03-28 2002-10-03 Nissan Motor Co Ltd 内燃機関のピストン駆動装置
JP2007327345A (ja) * 2006-06-06 2007-12-20 Nissan Motor Co Ltd 筒内直接噴射式内燃機関

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3638632B2 (ja) 1994-06-17 2005-04-13 ヤマハ発動機株式会社 エンジンの動弁装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS638632B2 (fr) * 1982-11-02 1988-02-23 Matsushita Electronics Corp
JP2002285857A (ja) * 2001-03-28 2002-10-03 Nissan Motor Co Ltd 内燃機関のピストン駆動装置
JP2007327345A (ja) * 2006-06-06 2007-12-20 Nissan Motor Co Ltd 筒内直接噴射式内燃機関

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Publication number Publication date
JP7151882B2 (ja) 2022-10-12
JPWO2020229860A1 (fr) 2020-11-19
WO2020229860A8 (fr) 2021-09-10

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