Internal combustion engine with high speed combustion and method for controlling an internal combustion engine

Abstract

To provide an innovative solution for an internal combustion engine which is characterized by both high operating efficiency and an extremely simple structure.SOLUTION: An engine includes at least one cylinder, and a first intake valve and a second intake valve that control flows of intake air from a first intake duct and a second intake duct, respectively. The two intake ducts communicate with a common intake manifold so as to receive air at the same pressure. During the intake stage, in each cylinder operating cycle, initially an opening and closing movement of only the first intake valve is activated while the second intake valve remains closed, and subsequently an opening and closing movement of only the second intake valve is activated while the first intake valve remains closed. In this way, the two air flows at the same pressure entering the cylinder give rise to a high turbulent kinetic energy (TKE), to the advantage of combustion efficiency and reduction of harmful exhaust emissions.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an internal combustion engine of the type including one or more cylinders, each having a series of intake, compression, expansion, and discharge stages during each operating cycle of the cylinder, and respective pistons slidable within the cylinder between TDC and BDC and operatively connected to a crankshaft. In particular, the invention relates to an internal combustion engine of the type including, for each cylinder: a first intake duct and a second intake duct opening into the cylinder at spaced apart locations and communicating with the same intake manifold so that both receive air at the same pressure; first and second intake valves associated with the cylinder for controlling admission of intake air flow from the first and second intake ducts, respectively, into the cylinder during an intake stage in each operating cycle of the cylinder; a device for actuating the first and second inlet valves to control the opening and subsequent closing of the first and second inlet valves during an inlet stage in each operating cycle of a cylinder; and This relates to an engine of the type including

[0002] The invention is generally applicable to internal combustion engines of any type, for example petrol or diesel. The relevant The device for actuating the intake valve may be of any type, in particular it may be a fixed oh and precise time and displacement in Conventional devices that control the intake valve, or opening and / or closing of the intake valve as engine operating conditions vary At the time of , and / or Intake valve rise of The actuator may be any known type of variable actuation device configured to vary the amount of force applied to the actuator. [Background technology]

[0003] Increasingly, CO2 emissions and particulate matter from gasoline and diesel internal combustion engines strict The regulations have led designers towards a series of measures (e.g., high compression ratio engines, engines operating according to the Miller-Atkinson cycle, recirculation of cooled exhaust gases or dilution of the air-petrol mixture with excess air, direct injection of fuel at high pressure, deactivation of one or more engine cylinders, etc.). drive but, However, these are Maximum power output per displacement unit and air, fuel, and ( If present ) It introduces new issues regarding the homogeneity of the mixture constituted by exhaust gas recirculation (EGR) and the formation of particulate matter associated with the quality of the fuel injector atomizer.

[0004] With a view to overcoming these drawbacks, the applicant has already proposed various engine solutions aimed at obtaining a high turbulent kinetic energy (TKE) of the air charge inside the cylinder in order to obtain a more rapid combustion propagation (see, for example, European Patent Application No. 20214913, filed on December 17, 2020, not yet published at the priority date of the present invention).

[0005] however, While having rapid combustion and high efficiency, A very simple configuration Yes If necessary, a simplified drive system for the intake valve can be used. of can also be adopted Inside The need for partial combustion engines is still felt. [Objective of the Invention]

[0006] Therefore, the object of the present invention is to provide a high operating efficiency and emergency to Simple The aim of this study is to propose an innovative solution for an internal combustion engine characterized by both a compact and flexible structure.

[0007] Another particular object of the invention is to propose an internal combustion engine, and a method for controlling the operation of this engine, that makes it possible, by very simple and low-cost means, to increase the combustion propagation speed in the cylinders of the engine, in order to improve the homogeneity of the air-fuel-EGR charge and to avoid the so-called "wall-wetting" phenomenon with the fuel injectors, even under the most severe conditions, such as when starting the engine cold.

[0008] Alternatively, the aforementioned advantages can be combined with a high operational flexibility of the engine thanks to the combined application of a variable actuation system of the engine's intake valves. to It is also within the scope of the invention to propose an internal combustion engine of the type shown. Summary of the Invention

[0009] Achieve one or more of the above objectives From a perspective , Book The invention is as set forth at the beginning of this description. The present invention relates to an internal combustion engine having the above-mentioned features, and is further characterized as follows: the device for actuating the first intake valve and the second intake valve comprises: During the intake phase of each cylinder cycle, first controlling the opening and subsequent closing of only the first intake valve while the second intake valve remains closed; Next and configured to control the opening and subsequent closing of only the second intake valve while the first intake valve remains closed. Tei , As a result, airflow at the same pressure enters the cylinder from the two intake ducts at different times, increasing turbulent kinetic energy and providing benefits in terms of combustion efficiency and reduced harmful exhaust emissions. . [Advantages of the invention]

[0010] Research and experimentation by applicant has shown that the alternating opening, at successive times, of the two intake valves of each cylinder of the engine generally enables: It was proven. Obtaining an improvement in the rate of propagation of combustion; The macro-motions organized inside the combustion chamber, namely the so-called swirl motion (flow rotating around the cylinder axis), the tumble motion (flow rotating around an axis perpendicular to the cylinder axis), and the cross-tumble motion (flow rotating around an axis perpendicular to the cylinder axis and perpendicular to the tumble axis), are modulated, resulting in the charge The homogeneity of promotion and in the combustion chamber fart Direct fuel injection stage , i.e. Reducing wall impingement phenomena during gasoline direct injection (GDI) child and.

[0011] The aforementioned advantage is that there are two intake ducts. spaced apart position in inside the cylinder flow in This is derived from the fact that the piston is approximately above Dead point (TDC) During the initial stage of the intake stroke, which begins when the intake valve is at he The airflow introduced into the cylinder through the first intake duct contains a swirl component and a tumble component. component and the hydrodynamic field including the cross-tumble component is Generate The opening of the first valve causes the two intake valves to open simultaneously. And R case Compared to strength degree Exercise place (Twice as strong in the ideal case, i.e., without viscous dissipation) is established .this twist expensive Intensity exercise place is a highly turbulent formation and direct fuel injection (if envisioned). Charge for of Suitable The fuel injection, characterized by a single injection or multiple injections, occurs during or after the first valve opening. You may start at . twist Intense exercise place and swirl of a specific strength and Thanks to the air, EGR (if present) oh Maximum homogeneity of the fuel and fuel mixture becomes Furthermore, especially during cold engine starts case , The fuel injected into the combustion chamber becomes more difficult to evaporate, resulting in Particulate matter ( but Increase (which is also caused by the more pronounced wall-wetting phenomenon), but the generated Swirl and Burning Burning spray and Interactions By , Burning Dropping To the wall collision (Impingement) Avoid have a beneficial effect on particulate matter emissions .

[0012] First intake valve closed And In the second part of the inhalation phase, Fuel injection can continue. Higher strength motion Thanks to the existence of the place, Most The proper air-fuel mixture arising Towards the end of the intake stroke, the second intake valve opens. he , then close again It will be. 2. Intake valve this Delayed Second Opening is two t Has the effect of: It is due to the first opening of the first valve. arise Swirl movement motion Field components and to oppose motion motion The place Generate , according to the maximum rise of this second actuation, and the second opening Get started crank angle to Therefore, Existing The swirl will eventually decay or its rotation direction will is reversed even a This phenomenon occurs at higher engine loads. especially It is necessary. strength Dynamics with a small swirl component motion One problem associated with the field is that the swirl rank Place not much Insensitive The point is that. As the stone gradually moves towards TDC, a tumbling motion teeth converted into turbulent kinetic energy on the other hand , swirl and its associated kinetic energy teeth, It continues to exist even after TDC, Burning During the baking, Through the combustion chamber wall Greater heat Dissipation causes. Therefore, To increase the rate of propagation of the flame To increase its strength Unlike the turbulent kinetic energy required, the kinetic energy associated with the swirl is good Instead, swirl damping obtained by opening a second valve is required. Swirl, Tumble ingredients (or Cross Tumble , but, Either way In any case, (around an axis perpendicular to the cylinder axis) In organization was Macro To exercise and conversion By doing so , Transfer of kinetic energy from swirl to tumble but possible Becoming , The possibility of conversion into turbulent kinetic energy is obtained. Useful for increasing combustion rate when the piston is close to TDC is. Second intake valve delay Open Release alone, It generates a "new" amount of turbulence, which dissipates but , The overall turbulent kinetic energy content at TDC is Intake valve of at the same time Follow Next By method Operation If you want to greater than vinegar do. disorder Flow Dissipation is proportional to the cube of the intensity of the turbulence itself, and start to Leave Many amount The generation of turbulence in this Large dissipation The occurrence of new turbulence By delaying ,ignition corner in the Ideally, Follow Next Intake valve Operation case Compared to the ignition angle to The available turbulent kinetic energy in double It is possible to That's often said , This means: Combustion stability Improvement of for example, charge of Dilution Increase The obvious advantage is the possibility .

[0013] The document French Patent Application Publication No. 3064676 states: S An internal combustion engine having two intake valves per cylinder is disclosed. , note that these intake valves are opened at subsequent times. The two intake valves are Associated with two intake ducts, One receives compressed air from the turbocharger Take The other receives further compressed air from an additional compressor located downstream of the turbocharger. take . The air flow at higher pressures is piston heads towards TDC During the journey 、 introduced into the cylinder like This occurs. Ta eye、 At higher pressures Can Associated with the intake duct that receives this air flow R Inlet valves open after other inlet valves open And , instead, The other intake valves open towards BDC. cormorant During the piston stroke to be carried out In other words, this prior art If , Two intake valves on the same cylinder of crankshaft rotation spaced apart angle The reason it is required to be open at this range is simply because the two intake ducts are supplied with air at different pressures. .

[0014] The solution known from French patent application FR 3064676 has the following drawbacks: the increased cost and complexity of the system due to the need to provide a pressure booster and, consequently, a unit for cooling the air before introducing it into the cylinder; The engine's heat capacity increases due to the presence of the booster. death , resulting in delayed warm-up and reduced catalytic converter efficiency and consequent harmful emissions. thing has worsened, Loss of efficiency due to energy absorbed by the booster, As a result Greater pumping work for the engine of The need raw Jiru. [Additional desirable features]

[0015] In a first embodiment, the device for actuating the two intake valves associated with the cylinder is of conventional type. case The engine includes a camshaft that operates the intake valves. The camshaft includes a first cam for actuating the first intake valve against the action of a return spring tending to hold the first intake valve closed, and a second cam for actuating the second intake valve against the action of a return spring tending to hold the second intake valve closed. In this embodiment, each S Linda operating cycle in During the intake phase, initially, the first cam causes opening and closing movements of only said first intake valve while the second intake valve remains closed; NextThe first cam and the second cam are configured and arranged on the camshaft such that the second cam causes opening and closing movement of only the second intake valve while the first intake valve remains closed. Place will be done.

[0016] In a second embodiment, the engine includes a variable actuation device for the first intake valve and the second intake valve, the variable actuation device being configured to: First Only the first intake valve, Next Only the second intake valve At successive times the aforementioned operating mode that releases, or , the first intake valve and the second intake valve Mutual stomach Same as Kazuyo Or relatively close came into contact crank angle to Leave Open Release, and the first intake valve and the second intake valve Mutual stomach Same as Kazuyo Or relatively close came into contact crank angle to Leave closed The second conventional operating mode is to lock or One of us only of and preferably a third operating mode in which only the second intake valve is opened and closed. realization It is configured to:

[0017] According to a first example, the variable actuation device may be of the type sold under the trademark MultiAir® and which is the subject of various patents of the applicant (including EP 0803642, EP 1555398, EP 1508676, EP 1674673, EP 2261471, EP 2693007, and EP 2801706). case The first and second cams respectively control first and second intake valves associated with the cylinders by respective electronically controlled hydraulic devices. Each of the two hydraulic devices is operated by a respective cam. And Tappets and A master cylinder with associated tappets that transfers pressurized fluid from the pressurized fluid chamber to slave cylinders that act as hydraulic actuators for each intake valve.and, and an electrically operated control valve that, when open, places the pressurized fluid chamber in communication with the low pressure discharge channel, thereby Intake valve Separated from each tappet And each return The spring opens the intake valve quick Quick closure To cause Designed are .

[0018] In another example, the first intake valve and before The actuating device of the second intake valve comprises: Ma A known type of variable actuation device includes a multi-profile cam. Thus, the device may be selectively operated to provide either a mode of operation in which only the first inlet valve is initially opened and then only the second inlet valve is opened at successive times, or a mode of operation in which the first and second inlet valves are opened simultaneously or nearly simultaneously.

[0019] In yet another example, the actuation devices of the first intake valve and the second intake valve are adapted to actuate the first intake valve and the second intake valve in response to a crank angle and are independently, and 、 Each valve moves independently of the other intake valves. Sucking Opening the valve closed Electromagnetic or electrical devices that have the ability to control air sky air A variable actuation device including a variable actuator.

[0020] Research and testing conducted by the applicant has shown that the first intake valve oh and the second intake valve Two Open cycle Ta Timing By setting this appropriately, Advantages of the invention demonstrated that the .

[0021] In one example, the midpoint of the opening phase of the first intake valve is: In the cylinder From TDC to BDC Pi The first half of the stroke is in progress, and the midpoint of the opening phase of the second intake valve is In the cylinder From TDC to BDC Pi It is in the second half of the intake stroke of the engine.

[0022] especially, Book In the example of the invention, S Linda of The piston is substantially at top dead center (TDC), or Top dead center to Close proximity Sometimes the first intake valve opens AndBefore the piston reaches bottom dead center (BDC), preferably at the end of the stroke from TDC to BDC. Medium between Nearby Closed when in And , on the other hand, A second intake valve B DC Nearby Preferably, the piston is directed towards TDC. hair And already Rising Open when And , the air flow That direction Intake manifold Reverse to the side Transfer The point at which the tendency ( At this point, (which may depend on the pressure in the intake manifold, the speed of crankshaft rotation, and engine load) And R Yo The intake valve actuation device is configured as follows.

[0023] In this example, During each operating cycle of the cylinder, First intake valve closed from Opening the second intake valve The progress up to On time Leave , S The piston in the cylinder is B Continue moving towards DC , creating a vacuum inside the cylinder As a result, the second intake valve opens. And When parable The piston is heading towards TDC and rising In case Even if there is , the vacuum previously created in the cylinder but , Further from the second intake duct air Absorb the charge of This allows for a high vacuum in the cylinder (depending on the closing angle of the first valve) About , 2nd times In the cylinder, Generated R inflow Velocity, flow rate, and turbulence become even larger As a result Obtained fluid mechanics target The field is highly turbulent and the propagation speed of the combustion perspective from Large This allows for significant benefits, especially when using EGR or excess air by air fuel charge This allows for increased dilution of Book This embodiment of the invention has the advantages described above. Synergistically increase difference Let This makes it possible.

[0024] In one embodiment, high Engine load time In No. The first intake valve is closed, and the first intake duct To the upstream side of Stand up Generates pressure waves that , The pressure wave General of Through the intake manifold The first and second intake ducts are sized so that the first and second intake ducts propagate into the second intake duct, thereby maximizing cylinder filling. .

[0025] In another example, the first Intake duct and the second intake duct is configured such that, under conditions of maximum engine charge and full opening of the second intake valve, the airflow entering the combustion chamber due to the opening of the second intake valve does not counteract the swirling motion of the airflow previously introduced into the combustion chamber due to the opening of the first intake valve. Yo The diameters and lengths are selected to be different.

[0026] In another example, the actuation devices for the first and second intake valves include: No. Control the rise of the first intake valve to be significantly lower than the rise of the second intake valve. As a result, the filling of the cylinder is mainly due to the opening of the second intake valve. It is composed. Book The invention also relates to an engine control method. [Brief explanation of the drawings]

[0027] Further characteristics and advantages of the invention will become apparent from the description that follows, given purely by way of non-limiting example, with reference to the accompanying drawings, in which:

[0028] [Figure 1] FIG. 1 is a perspective view of a top view of a combustion chamber of a cylinder of an internal combustion engine and its associated intake and exhaust ducts. [Figure 2] FIG. 1 is a perspective view of a top view of a combustion chamber of a cylinder of an internal combustion engine and its associated intake and exhaust ducts.

[0029] [Figure 3] 1 is a perspective view of a conventional type of actuation system for two intake valves associated with a cylinder; FIG.

[0030] [Figure 3A] 4 illustrates a variant of FIG. 3 corresponding to an example of the first embodiment of the invention.

[0031] [Figure 4] 1A-1C illustrate various example implementations of the opening and closing cycles of the two intake valves associated with each cylinder of an internal combustion engine according to different embodiments of the invention, compared to a conventional cycle that assumes both intake valves are open at BDC and both intake valves are closed at TDC. [Figure 5] 1A-1C illustrate various example implementations of the opening and closing cycles of the two intake valves associated with each cylinder of an internal combustion engine according to different embodiments of the invention, compared to a conventional cycle that assumes both intake valves are open at BDC and both intake valves are closed at TDC. [Figure 6] 1A-1C illustrate various example implementations of the opening and closing cycles of the two intake valves associated with each cylinder of an internal combustion engine according to different embodiments of the invention, compared to a conventional cycle that assumes both intake valves are open at BDC and both intake valves are closed at TDC. [Figure 7] 1A-1C illustrate various example implementations of the opening and closing cycles of the two intake valves associated with each cylinder of an internal combustion engine according to different embodiments of the invention, compared to a conventional cycle that assumes both intake valves are open at BDC and both intake valves are closed at TDC. [Figure 8]1A-1C illustrate various example implementations of the opening and closing cycles of the two intake valves associated with each cylinder of an internal combustion engine according to different embodiments of the invention, compared to a conventional cycle that assumes both intake valves are open at BDC and both intake valves are closed at TDC. [Figure 9] 1A-1C illustrate various example implementations of the opening and closing cycles of the two intake valves associated with each cylinder of an internal combustion engine according to different embodiments of the invention, compared to a conventional cycle that assumes both intake valves are open at BDC and both intake valves are closed at TDC. [Figure 10A] 1A and 1B are diagrams illustrating the advantages of the present invention. [Figure 10B] 1A and 1B are diagrams illustrating the advantages of the present invention. [Figure 10C] 1A and 1B are diagrams illustrating the advantages of the present invention. [Figure 10D] 1A and 1B are diagrams illustrating the advantages of the present invention. [Figure 10E] 1A and 1B are diagrams illustrating the advantages of the present invention.

[0032] [Figure 11] 1 is a variable actuation system for intake valves of the type known by the name MultiAir that can be used in embodiments of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0033] 1 and 2, reference numeral 2 indicates throughout any 1 shows a combustion chamber associated with cylinder 1 of a known type of internal combustion engine. The axis of the cylinder is designated C1. Figures 1 and 2 are any known shape and each other to Separated position in Opening in combustion chamber 2 mouth The two suction ducts 3A and 3B are shown. friend ,same FirstIt communicates with an intake manifold 30 (only partially shown) and therefore receives air at the same pressure from the air supply line to the engine. In the example shown, the engine Because it is not a supercharged type , both ducts 3A and 3B are at ambient pressure to Air is received in the supercharged engine. Even if , in any case , ducts 3A and 3B are the same one pressure of Receive air.

[0034] 1 and 2 also show a cylinder 1 associated with an internal combustion engine in an exhaust manifold 5 (partially visible in FIG. 2). merge Two exhaust ducts 4A and 4B are shown.

[0035] The engine may be of any known type, with controlled ignition or compression ignition, and it will be understood that the drawings show only the parts that are relevant for the purposes of the present invention, and that the structure and overall configuration of the engine may be in any known manner.

[0036] According to the prior art, two intake valves of conventional poppet type, namely a first intake valve VA and a second intake valve VB, having a stem and a circular head, are associated with the two intake ducts 3A, 3B.

[0037] As will be further illustrated below, for the purposes of the present invention, the drive system for the intake valves VA, VB may be of any known type. Purely by way of example, Figure 3 shows a conventional type of intake valves VA, VB including a camshaft 6 rotatably supported within the structure of the engine's cylinder head and rotated in a conventional manner by a transmission device (e.g., a toothed belt transmission device) from the crankshaft (not shown) of the internal combustion engine. ofThe actuating device is shown in Fig. 3. The camshaft 6, only a portion of which is shown in Fig. 3, includes two cams 6A, 6B which actuate the first intake valve VA and the second intake valve VB, respectively. In the conventional example illustrated in Fig. 3, the two cams 6A, 6B actuate the two valves VA, VB by means of respective rocker arms 7A, 7B, each of which is connected to a cylinder head Structure By construction Supported Support part 8 top to swivel type to Can be attached one end Department and each intake valve to Opposites at work of end Department It has the following.

[0038] Explained here Book Referring again to the first embodiment of the invention, the cams 6A, 6B are arranged in the same manner as illustrated in FIG. 3A to obtain the type of lift profile illustrated in any one of FIGS. like It will be corrected.

[0039] Figure 4 shows the rise profiles of the two intake valves VA, VB according to an example of the first embodiment of the present invention. The displacement of each intake valve is Engine rotation angle as a function of Here, The arrangement to be adopted So, the engine rotation angle is equal to 360 degrees. teeth , the piston inside the cylinder Top dead center ( TDC ) The piston position at BDC corresponds to the condition at 540 degrees crank angle. to handle.

[0040] In Figure 4, line LC is equipped with a conventional cam. Follow Previous engine case 1 illustrates the rising diagram of the intake valve in the conventional solution. case In this case, the two intake valves VA and VB are simultaneously driven according to the profile LC. and Synchronous control. in In traditional solutions, two inhalationThe valve opens just before TDC. tree First, crank angle 470 degrees Nearby The maximum opening condition is reached at a crank angle equal to 600 degrees. of Nearby In closed again And To achieve this result, the two cams 6A and 6B are have the same profile, resulting in an ascending profile LC, and As can be seen in FIG. mosquito Mushaft 6 in same First corner rank Place Yes do.

[0041] As illustrated in Figure 4 Book In an embodiment of the invention, the cams 6A, 6B have different configurations (as in FIG. 3A) and are mounted on the camshaft 6. corner occasionally Differently oriented The shape of the two cams 6A and 6B and Orientation are calculated by LA and LB in Fig. 4. Show Intake valves VA and VB of Generate a climb profile Ta (Fig. 4 and Since then The rising profiles LA and LB shown in It's just something Please note that sea ​​bream ).

[0042] Observed Should The first important characteristic is each Cylinder motion Intake stage of the working cycle Medium First, the second intake valve VB remains closed. In the meantime , the opening and closing movements of only the first intake valve VA are Operation And, Next , the first intake valve VA remains closed In the meantime , the opening and closing movement of only the second intake valve VB is Operation This is what is done.

[0043] FIG. 4 shows a particularly preferred example of an embodiment, in which the piston in the cylinder is near TDC. to One day ( That is, ,T Just before DC Also Immediately after At a position close to TDC ), the first intake valve VA begins to open, and then crank angle 540 degrees earlier , i.e., the piston in the cylinder still Move towards BDC Inside , which is first closed when the BDC has not yet been reached. In response to this , second intake valve VB occurs after the piston in the cylinder has reached BDC and is already rising towards TDC (for example, around a crank angle equal to 560 degrees). open And , nine After an additional rotation of the crankshaft , for example after a rotation equal to about 90 degrees Closed to And do.

[0044] Referring again to FIG. 4, the maximum rise of the first intake valve VA is approximately 80% of the maximum rise of a conventional cycle in which the intake valves VA, VB are simultaneously opened and closed according to the conventional rise line LC, while the maximum rise of the second intake valve VB is equal to about 3 / 8 of the maximum rise of the first intake valve VA (also, according to the conventional rise line LC). maximum It can be observed that the increase in

[0045] Figures 5 to 8 show 5 is a view similar to the embodiment of FIG. 4 illustrating an example of an additional embodiment of the present invention; Ascent profile shape ( Figures 5 and 6) or timing of the rising profile ( Figures 7 and 8) but This is different from the example in Figure 4. As can be seen, Figures 5 and 6 case , opening of intake valves VA and VB time and closure time is illustrated in Figure 4. Opening and closing times Effectively corresponds to On the other hand ,Fig.7 In the case , the second intake valve VB is closed, and the first intake valve VA is closed. And Immediately after that, it began to open On the other hand, the last Figure 8 In the case of The second intake valve begins to open just before the first intake valve VA closes.

[0046] All the foregoing embodiments are What is common is that during the intake stage in the cylinder, there is a first period during which only the first intake valve VA is substantially open while the second intake valve VB remains closed, while during a second period only the second intake valve VB is open while the first intake valve VA remains closed.

[0047] Opening of two intake valves cycle Regardless of the timing of the closing cycle, the aforementioned characteristics are R air In charge Turbulence Kinetic Energy (TKE) of This allows for the benefits of increased This is related to the configuration of the intake ducts illustrated in FIG. 2, i.e., the intake ducts open at positions spaced apart from each other on both sides of the plane 4. Therefore, Only from intake duct 3A The air S When the airflow is introduced into the cylinder, it has a swirl component (a flow that rotates around the C1 axis of the cylinder). have fluid mechanics target Then, the first intake valve VA closes. And , the second intake valve VB opens And When direction From intake duct 3B come flow but , destination to Induction The fluid force target It interferes with the field and increases its TKE. of Turbulence Kinetic Energy of The increase is Once air and fuel and Mixture of air exploded ( Gasoline engine case is the spark plug Following the ignition , or diesel engine case is the compression in the cylinder By ) Then , the propagation speed of combustion of Increase difference Let result .

[0048] The aforementioned advantages of increasing TKE within the airflow introduced into the cylinder are apparent from the embodiments of FIGS. In some cases, synergistic increase This case ,actual 、 First intake valve VA is closed And When the piston in the cylinder moves toward BDC, hair It continues to fall and to Vacuum give rise to . child In the case of these embodiments, No.2, intake valve is after BDC, i.e., when the piston has already risen again towards TDC. Open Ku Nevertheless, in the cylinder before The vacuum field established in this stage In However, the opening of the second intake valve VB A forceful air inflow from the second intake duct 3B into the cylinder occurs, Cylinder Within fluid mechanics target High in the field stomach TKE of Generate vinegar That meaning Taste.

[0049] the above death As mentioned above, The present invention relates to an internal combustion engine having a device for actuating intake valves of the conventional type, in which the rise profile of the two intake valves is fixed and predetermined. and an internal combustion engine provided with a variable intake valve drive system of Both fruit It can be equipped.

[0050] Thus, for example, see Figure 6 Then , No. Opening of suction valve VA of 1 closed of give rise to Cam 6A is For example, electrohydraulic device to Controlled by , LA1 In fact, hydraulic means Rika Mu exercise from the movement of the intake valve. in, Sucking Movement to enter the company law Rules Non-monotonic and However, Using the same variable drive system , the rise profile of the valve VA is varied. , for example, according to profile LA2 Similarly, the actuating device combined with the cam 6B is shown in FIG. Show Movement according to the specified ascent profile LB1 law Create rules Make However, The engine increases the effective valve VB Obtained according to profile LB2 It is possible to Variable Drive System of Preparation hand Good too.

[0051] In one example, The present invention provides Developed by the same applicant and sold under the MultiAir brand are Types of engine intake valves forAn internal combustion engine equipped with a variable drive system suitable It is used.

[0052] Figure 11 shows a schematic example of a Multiair variable actuation system. In this case, each of the intake valves VA, VB (Figure 11 shows the devices associated with valve VA) is actuated by an electronically controlled hydraulic device 8 to drive a respective cam 6A or 6B. via operation And Cam 6 is return It operates a tappet 9 which is kept in contact with the cam 6 by a spring 10. The tappet 9 Ma Associated with the pumping piston 11 of the star cylinder The master cylinder transfers pressurized fluid from chamber 12 to the chamber of slave cylinder 13, whose piston 14 acts as an actuator for intake valve VA. Intake valve VA teeth , By spring 15 Turn intake duct 3A to the closed position. hair hand Pull All of the aforementioned components are held together by the engine cylinder head structure 16. The solenoid valve 17 is controlled by an electronic control unit E. When the solenoid valve is in a closed state, it provides communication between the pressurized fluid chamber 12 and the low pressure environment 18. Block and low pressure environment 18 The solenoid valve 17 communicates with a fluid accumulator 19 and with an inlet 20 intended to communicate with the engine lubrication circuit. When the solenoid valve 17 is in the closed state, the pressurized fluid chamber 12 is isolated, so that the pressure provided by the cam 6 R Tappet 9 Exercise , via the fluid in chamber 12 and slave cylinder 13 To intake valve VA Transmission Achieved Yo Cam 6 keeps intake valve VA open. In , by the electronic control unit E the law of nature Opening of the controlled solenoid valve 17 but , discharge of pressurized fluid chamber 12 This causes the Spring 15 twist Intake valve VA but closure will be In this state, the intake valve VA is driven by the cam 6. R Tappet 9 motion The impact of not receive .

[0053] This explanation is The basic operating principle of the Multiair system Described solely as an indication been There are . Book The applicant: Various embodiments of this system have been developed, including: already The above The subject of various published patent applications, including R .

[0054] Book invention teeth , for example, electromagnetic drive systems, for example of the type including multi-profile cams. Ma or variable drive system etc. of any Known types of variable actuation systems for intake valves and set combination Even Available a It is understood that sea ​​bream .

[0055] Adopt a variable drive system case , above Note of Operation Mode That is, the mode in which only the first intake valve is operated first, and then only the second intake valve is operated at successive times is ,engine Identification of of Operating conditions Implemented only under on the other hand, Engine other Under operating conditions, each S Linda's two intake valves teeth, Conventional direction Controlled by the formula , opened and closed at the same time do.

[0056] Figure 9 shows Book In a variant of the invention, the two intake valves are raised of Another example of the figure Show vinegar 。

[0057] 10A-10E compare the conventional standard implementation where both intake valves open at TDC and close at BDC. Book The main advantages that can be obtained by the invention are presented.

[0058] Figure 10A shows the standard implementation. In some cases , figureof 7 Qualitative Diagram corresponds to Book of the invention one In an embodiment In some cases , the change in the mean value of the turbulent kinetic energy (TKE) in the combustion chamber transformation The diagram in FIG. 10A shows the delay of the second intake valve. Open BDC In the vicinity Turbulence Kinetic Energy of new to Increase This indicates that ,the result, Although it has been scattered, At the next TDC Can TKE value is the standard case significantly higher than become .

[0059] Figure 10B shows the different combustion processes that occur in the combustion chamber. Organized to was Macro 1 illustrates a schematic diagram of the movement. child These figures are indicates the reference system, The X-axis is the plane of symmetry of the intake valve duct (Plane 4 in Figure 2) exists within and, combustion chamber fart Air introduction direction and Matches Therefore, the tumble motion is in a plane perpendicular to the Y vector. a It is defined as 、 The cross tumble motion is in a plane perpendicular to the X vector. a The swirl is defined as the flow of a liquid in a plane perpendicular to the Z vector. a The so-called tumble, cross tumble, and swirl Each index of is defined as follows: Tumble index = ω Tumble / ω Engine Cross tumble index = ω CrossTumble / ω Engine Swirl index = ω Swirl / ω Engine ω Engine is the engine rotation speed, and ω Tumble , ω CrossTumble , and ωSwirl is the average angle of each motion Fast degrees [rad / sec].

[0060] FIG. 10C shows the effect of the opening of the second intake valve on the swirl generated by the preceding opening movement of the first intake valve. influence Show Break The line indicates the time after the first intake valve opening cycle. to , the opening of the second intake valve If not done , the swirl index Will show refers to a trend. During combustion, Swirl Strength is quite large , This means: heat exchange but Increase death, engine efficiency but It is noted that the sea ​​bream The solid line is Showing the advantages of the present invention over swirl, Second intake valve opens And R Soon , Swirl Opening the second intake valve Medium In proportion to the air introduced into Attenuated . No. The opening movement profile of the intake valve of change have the ability to With an actuating device for the intake valve By the law of nature ,combustion Medium to 、 Chamber Inside It is possible to adjust the strength of the swirl present in and It can be inferred that the dashed / dotted lines This refers to standard operation, and of course Formation of swirl Thoughts Determined attitude do not have 。

[0061] FIG. 10D illustrates the effect of the opening of the second intake valve on the tumble generated by the preceding opening cycle of the first intake valve. influence Show vinegar. Opening of the second intake valve At the start (In this example, a crank angle of 500 degrees) to swirl index of sudden Decrease (visible in Figure 10C) There is a significant increase in the tumble index It should be noted that . As with the standard example, from the crank angle of 660 degrees, the tumble index drops to zero because the tumble is compressed by the movement of the piston, and the kinetic energy is disturbed. Flow kinetic energy strange exchange Will be ( See also Figure 10A )。 crank angle but 660 degrees ~ 700 degrees During , by canceling the tumble Generated dissipation By Dissipation is replaced by For , TKE's further No dissipation occurs .

[0062] Figure 10E shows the trend of the cross tumble index. . Similar to the Whirl (Fig. 10C), this motion is similar to the standard actuation. case to teeth Also, the tumbling motion (Fig. 10D) case Similarly, the cross tumble movement No. Opening movement of intake valve 1 later Opening the second intake valve time to The activated swirl motion is due to the transformation Tumble motion case Similarly, the cross tumble motion occurs at a crank angle of 660 to 700 degrees. of TKE within the range support We support this.

[0063] In conclusion, Swirl's modularity is different from other organization Affected by exercise It is understood that Therefore, the first intake valve and the second intake valve successive Change the parameters that define the operation. transformation By doing so, the TKE value required at TDC can be While ensuring , it is possible to optimize the need for optimal air-fuel mixing. 。

[0064] In one embodiment, the first Intake duct and the second intake duct is At high engine loads, the first intake valve closes First intake duct A pressure wave is generated that rises upstream of the common of Through the intake manifold The intake duct is dimensioned to propagate through the intake duct to maximize cylinder filling. .

[0065] In another example, the first Intake ductand the second intake duct is different diameters and different lengths, the different diameters and different lengths being Maximum engine charge and full opening of second intake valve conditions Then, the second intake valve opens. R The air flow into the combustion chamber is increased by the opening of the first intake valve. Inside to destination The swirling motion of the airflow introduced into the stomach Selected to be R .

[0066] In another example, the actuation devices for the first and second intake valves include: The first intake valve rises Significantly lower than the rise of the second intake valve Ku configured to control Tei ,the result, S Linda's Filling is mainly done by opening the second intake valve. Obtained.

[0067] In essence, without prejudice to the principles of the invention, the embodiments and structural details may vary widely with respect to those described and illustrated purely by way of example, without departing from the scope of the invention as defined in the appended claims.

Claims

1. 1. An internal combustion engine having one or more cylinders and respective pistons operatively connected to a crankshaft sliding within said cylinders between TDC and BDC, said internal combustion engine configured to perform a series of intake, compression, expansion, and discharge stages during each operating cycle of each cylinder; The internal combustion engine has, for each cylinder: a first intake duct and a second intake duct opening into the cylinder at spaced apart locations, the first intake duct and the second intake duct both communicating with the same intake manifold and thereby receiving air at the same pressure; first and second intake valves associated with the cylinder for controlling the flow of intake air from the first and second intake ducts, respectively, into the cylinder during the intake stage of each operating cycle of the cylinder; and a device for operating the first and second intake valves, controlling the opening and subsequent closing of the first and second intake valves during the intake stage of each operating cycle of the cylinder; and Equipped with the device for actuating the first and second intake valves is configured to, during the intake stage of each cylinder operating cycle, firstly control the opening and subsequent closing of only the first intake valve while the second intake valve remains closed, and then control the opening and subsequent closing of only the second intake valve while the first intake valve remains closed, so that the air flows from the first and second intake ducts communicating with the same intake manifold into the cylinder at different times create an increase in turbulent kinetic energy, resulting in advantages of combustion efficiency and reduced harmful exhaust emissions. Internal combustion engine.

2. The internal combustion engine includes a camshaft for operating the first intake valve and the second intake valve, the camshaft including: a first cam for actuating the first intake valve against the action of a return spring tending to hold the first intake valve closed; a second cam for actuating said second intake valve against the action of a return spring tending to hold said second intake valve closed; and the first cam and the second cam are constructed and arranged on the camshaft such that during each intake stage, first the first cam causes the opening and subsequent closing movement of the first intake valve while the second intake valve remains closed, and then the second cam causes the opening and subsequent closing movement of the second intake valve while the first intake valve remains closed.

10. The internal combustion engine of claim 1.

3. The internal combustion engine includes a variable actuation device for the first intake valve and the second intake valve, the variable actuation device being configured to: a first operating mode in which first only the first inlet valve and then only the second inlet valve are opened at successive times; or a second operating mode in which the first intake valve and the second intake valve are opened at substantially the same crank angle as each other and the first intake valve and the second intake valve are closed at substantially the same crank angle as each other; or a third operating mode in which only one of the first intake valve and the second intake valve is opened and closed; configured to produce either 3. An internal combustion engine according to claim 1 or 2.

4. 4. The internal combustion engine of claim 3, wherein the first operating mode is implemented when the engine speed is less than 3000 rpm.

5. The first cam and the second cam control the first intake valve and the second intake valve, respectively, by respective electronically controlled hydraulic devices, each of the hydraulic devices comprising: a tappet operated by each of the first cam and the second cam; a master cylinder associated with the tappet for transferring pressurized fluid from a pressurized fluid chamber to a slave cylinder acting as a hydraulic actuator for each of the first and second intake valves; at least one electrically operated control valve configured, when open, to communicate the pressurized fluid chamber with a low pressure delivery channel, thereby isolating the first and second intake valves from their respective tappets and causing the closing of the first and second intake valves by action of their respective return springs; Including, 3. The internal combustion engine of claim 2, wherein the electrically operated control valves of each of the hydraulic devices are controlled by an electronic control unit, the electronic control unit configured and programmed to activate an operating mode only under one or more predetermined operating conditions of the internal combustion engine, wherein during each intake stage, in the operating mode, first an opening movement and subsequent closing movement of only the first intake valve occurs while the second intake valve remains closed, and then an opening movement and subsequent closing movement of only the second intake valve occurs while the first intake valve remains closed.

6. 6. An internal combustion engine according to claim 1, wherein a midpoint of an opening stage of the first intake valve is located in a first half of an intake stroke of the piston from the TDC to the BDC, while a midpoint of an opening stage of the second intake valve is located in a second half of the intake stroke of the piston from the TDC to the BDC.

7. 7. An internal combustion engine according to claim 1, wherein the device for actuating the first and second intake valves is configured such that during the intake stage of each operating cycle of the cylinder, the first intake valve is opened when the piston in the cylinder is substantially at TDC and closed before the piston reaches BDC, while the second intake valve is opened after the piston has reached BDC and is moving upward towards TDC and closed as soon as, after further rotation of the crankshaft, the air flow entering through the first intake duct controlled by the second intake valve tends to reverse its direction and exit the cylinder through the same first intake duct.

8. 4. The internal combustion engine of claim 1 or 3, wherein the device for actuating the first and second intake valves is a variable actuation device including an electromagnetic or electro-pneumatic actuator.

9. 4. The internal combustion engine of claim 3, wherein the device for actuating the first and second intake valves is a variable actuation device of a type including a cam having multiple profiles, the variable actuation device being selectively operable to produce either an operating mode in which the first and second intake valves are opened at successive times or an operating mode in which the first and second intake valves are opened substantially simultaneously.

10. the first intake duct and the second intake duct have different configurations; and / or 10. An internal combustion engine according to claim 1, wherein the first and second intake valves are poppet-type valves having circular heads and stems, with the heads having different diameters.

11. 11. The internal combustion engine of claim 1, wherein the first and second intake valves are poppet-type valves having circular heads and stems, and the maximum lift of the first intake valve is greater than D / 5, where D is the diameter of the circular head of the first intake valve.

12. 12. An internal combustion engine according to any one of claims 1 to 11, wherein the first and second intake ducts are sized such that, at high engine loads, the closing of the first intake valve generates a pressure wave that rises upstream of the first intake duct and propagates into the second intake duct, maximizing filling of the cylinder.

13. 13. An internal combustion engine according to claim 1, wherein the first and second intake ducts have different diameters and lengths selected so that, under conditions of maximum charge of the internal combustion engine and full opening of the second intake valve, the air flow entering the combustion chamber by opening the second intake valve does not counteract the swirling motion of the air flow previously introduced into the combustion chamber by opening the first intake valve.

14. 14. An internal combustion engine according to any one of claims 1 to 13, wherein the device for actuating the first and second intake valves is configured to control the lift of the first intake valve to be lower than the lift of the second intake valve, so that filling of the cylinder is obtained mainly due to opening of the second intake valve.

15. 1. A method of controlling operation of an internal combustion engine including one or more cylinders and respective pistons sliding within said cylinders between TDC and BDC and operatively connected to a crankshaft, wherein during each operating cycle in each cylinder, a series of intake, compression, expansion, and discharge stages occur; The internal combustion engine has, for each cylinder: a first intake duct and a second intake duct opening into the cylinder at spaced apart locations, the first intake duct and the second intake duct both communicating with the same intake manifold and thereby receiving air at the same pressure; first and second intake valves associated with the cylinder for controlling the flow of intake air from the first and second intake ducts, respectively, into the cylinder during the intake stage of each operating cycle of the cylinder; and a device for actuating the first and second intake valves to control the opening and subsequent closing movements of the first and second intake valves during the intake stage of each operating cycle of the cylinder; The method comprises: during the intake stage of each cylinder's operating cycle, the device for operating the first and second intake valves first controls the opening and subsequent closing of only the first intake valve while the second intake valve remains closed, and then controls the opening and subsequent closing of only the second intake valve while the first intake valve remains closed, so that the airflows from the first and second intake ducts communicating with the same intake manifold enter the cylinder at different times, resulting in increased turbulent kinetic energy, which provides advantages in combustion efficiency and reduced harmful exhaust emissions.

16. 16. The method of claim 15, wherein the first intake valve is opened when the piston in the cylinder is substantially at the TDC and closed before the piston reaches the BDC, while the second intake valve is opened after the piston reaches the BDC and has already risen toward the TDC and closed after further rotation of the crankshaft.

17. The internal combustion engine has a variable actuation device for the first intake valve and the second intake valve, the variable actuation device being configured to: a first operating mode in which the first and second intake valves are opened at successive times; or a second operating mode in which the first intake valve and the second intake valve are opened at substantially the same crank angle as each other and the first intake valve and the second intake valve are closed at substantially the same crank angle as each other; or a third mode of operation in which only one of the first intake valve and the second intake valve is opened and closed; The method of claim 15 or 16, wherein the method is controlled to produce any one of the following:

18. 18. The method of claim 17, wherein the first operating mode is implemented when the engine speed is less than 3000 rpm.

19. 19. The method of any one of claims 15 to 18, wherein the first and second intake ducts are sized such that, at high engine loads, the closing of the first intake valve generates a pressure wave that builds up upstream of the first intake duct and propagates into the second intake duct, maximizing filling of the cylinder.

20. A method according to any one of claims 15 to 19, wherein the first intake duct and the second intake duct have different diameters and different lengths, and the different diameters and different lengths are selected so that, under conditions of maximum engine charge and full opening of the second intake valve, the air flow entering the combustion chamber upon opening of the second intake valve does not counteract the swirl motion of the air flow previously introduced into the combustion chamber upon opening of the first intake valve.

21. 21. The method of any one of claims 15 to 20, wherein the device for actuating the first and second intake valves is configured to control the lift of the first intake valve to be lower than the lift of the second intake valve, so that filling of the cylinder is obtained mainly due to opening of the second intake valve.

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