RU2453717C2 - Internal combustion engine - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: piston engine comprises engine control system and valve timing phase variation system. Intake pipe houses blow valve while cylinder accommodates intake and discharge valves driven by camshaft. Blow receiver is arranged between blow valve and intake valve. In compliance with this invention, blow valve is opened by partial or complete displacement of throttle driven by common armature of several electromagnets in response to engine control system and valve timing variation system instructions, while intake and discharge valves are driven with no part of valve timing system. Note here that intake valve opens before blow valve to communicate combustion chamber with blow receiver but closes after, before or at a time with blow valve after BDC of intake stroke.

EFFECT: improved operating performances.

13 cl, 13 dwg

Description

The invention relates to the field of piston internal combustion engines. In the text and in the illustrations (Fig. 1 ... Fig. 13) the following abbreviations are adopted:

- ICE - internal combustion engine,

- M _max - the maximum moment of the internal combustion engine,

- P _max - the maximum power of the internal combustion engine,

- KS - combustion chamber,

- V _cc - volume of the combustion chamber,

- exhaust gas - exhaust (residual) gases,

- VPC - intake valve

- OFF - exhaust valve,

- RP - purge receiver,

- V _RP - volume RP,

- R _RP - pressure in RP, atm,

- TDC - top dead center of the piston,

- BDC - the bottom dead center of the piston,

- EMZ - electromagnetic damper,

- KSUD - an integrated engine control system,

- SIFG - system for changing the valve timing,

- V _C - the volume of the cylinder,

- P _C - pressure in the cylinder, atm.

On the pie charts of the valve timing:

- the opening or closing angle of the valves is counted clockwise, starting from the TDC of the beginning of the intake stroke, in degrees. crankshaft rotation

- thick lines correspond to the closed state of the valves, thin lines to the open state,

- φ are the angles between the moments of opening or closing of the valves,

- α - the angles between the TDC or BDC and the moment of opening of the valves,

- β are the angles between TDC or BDC and the moment of valve closure.

Features of the operation of various types of internal combustion engines are considered on the example of a single-cylinder, four-stroke gasoline internal combustion engine with an injection power system.

In the illustrations:

- Figure 1 - classic ICE,

- Figure 2 is a pie chart of the timing of the internal combustion engine of Figure 1,

- Figure 3 - ICE with an electromagnetic valve actuator,

- Figure 4 is a phase diagram of the engine timing of Figure 3 in partial load modes.

- Figure 5 - ICE with EMZ in the intake manifold,

- Fig.6 is a phase diagram of the engine timing of Fig.5 in the partial load mode,

- Fig.7 - EMZ,

- Fig - EMZ with non-orthogonal partitions,

- Fig.9 - EMZ with cylindrical partitions,

- Figure 10 is a phase diagram of the gas distribution of internal combustion engines with EMZ in full load mode,

- 11 is a phase diagram of the timing of the internal combustion engine with EMZ in the forced blow mode,

- Fig - ICE with one EMZ on two cylinders,

- Fig - phase diagram of the gas distribution engine with EMZ in the vacuum braking mode.

The classic ICE, despite a number of shortcomings, is still widely used in industry and transport. Such an internal combustion engine, see FIG. 1, generally comprises a cylinder 1 with a piston 2, VPK 3, VOK 4. The valves are driven by cams 5 of the camshaft 6. A piston 2 rotates the crankshaft through a connecting rod 7, and the fuel nozzle and spark plug are conventionally not shown . Figure 2 presents a diagram of the valve timing. ICE is shown at the end of the exhaust stroke, the piston almost reaches the TDC.

At low and idle speeds, the exhaust of such an engine has high toxicity (high levels of CO, CH). This is due to the fact that at the end of the exhaust stroke the inertia of the exhaust on the upward movement of the piston is not large, and it largely remains in the CS in the form of exhaust gas. In subsequent intake strokes, the exhaust gas is mixed with a fresh charge and makes it difficult to burn.

There is a time when the pressure to reduce the toxicity of the exhaust end of the exhaust stroke as a seek from the inlet conduit may be better to blow air toward the COP of 3 to OFF MIC 4. The fact that near TDC during valve overlap (angle φ ₃₄₎ in the inlet pipe is larger than in the outlet, at this time the most intensive purge occurs. Denote this time T _about .

According to the diagram, Figure 2, we denote the moment of the beginning of this time (calculated in deg.) As α ₀ .

It is clear from the diagram that if VHF 3 opens early - α ₃ > α ₀ , then a large volume of exhaust gas has time to enter the inlet pipe through the ajar open HVM 3, and upon subsequent purging of the exhaust gas enters the CS.

If α ₃ <α ₀ , then the time T ₀ expires, and the purge does not occur at all. For each specific mode of operation of the internal combustion engine there is a α ₀ , therefore, the purge efficiency is different at different speeds and at different loads of the classic internal combustion engine. Good purge is obtained only in a small range of crankshaft rotational speeds (average rpm - 2000-3000 1 / min) since it is for this regime that empirically determined average values of the valve timing angles α ₃ , α ₄ , β ₃ , β ₄ , φ ₃₄ and etc.

With an increase in the speed of the internal combustion engine, the time when the VPK 3 is fully open falls, the fresh charge falling into the cylinder falls, and, as a result, M _max and P _max , the internal combustion engine “does not accept” at high speeds.

To increase the charge at high RPM 3 revolutions, it is necessary to start opening as early as possible to the TDC, increasing the angle α ₃ and, accordingly, increasing the valve overlap φ ₃₄ . However, in this case (see FIG. 1), the exhaust gases, being under increased pressure, begin to “shoot” into the intake pipe, then they in an increased volume climb back into the cylinder at the intake stroke, and, starting with a certain value α ₃ , φ ₃₄ , the increase in fresh charge stops. As noted in / 1 /, "in most cases, high-speed engines have wider valve timing than low-speed engines."

Thus, at low, medium and high revolutions, the internal combustion engine must be operated with its specific gas distribution phase angles in order to obtain minimum toxicity and maximum power and torque.

Recently, in the automotive industry, ICE with "variable valve timing" has been increasingly used. Almost all well-known companies - BMW, HONDA, ... - developed their own versions of mechanical, electromechanical, etc. systems (CIFG). Changes in the valve timing over a wide range of revolutions are achieved, for example, as noted in / 2 /, either by turning the camshaft, or by using additional special-profile cams that control several intake and several exhaust valves of one cylinder. At different engine speeds and loads, the opening angles (α ₃ ) of the intake valves (usually of different diameters) are different, and the height of their lift is different. This ensures a high efficiency of purging the compressor, a sufficient degree of turbulence of the air charge at the inlet, and by the time the piston starts moving downward at the inlet, a sufficient total flow area of all inlet valves is sufficient to gain full charge of the cylinder at high speeds. The effectiveness of SIFG today is such that, for example, with toxicity according to the Euro-3 standard, such ICEs have a specific power of 125 hp. per liter of naturally aspirated volume / 2 /.

It should be noted that the more effective the mechanical SIFG, the more difficult it is (it is necessary to control several valves), more expensive and more cumbersome. In some types of internal combustion engines, up to five valves per cylinder are used.

A further step in terms of improvement, according to / 2 /, is the use of electromagnetic valve actuators under the control of an integrated engine management system (ECC).

Such an internal combustion engine (see FIG. 3) contains all the components of the classical internal combustion engine of FIG. 1, but the valves of the VPC 3 and VCO 4 valves are driven by electromagnets 9, 10, respectively, under the control of the ACS 11.

The source data for the CSAC are the well-known parameters:

- Turnovers - n,

- Air flow - V _B

- CO or O ₂ level,

- Impulse "beginning" - T _N ,

- Coolant temperature - T _OHL , etc.

According to these data, the engine control system determines the moments of opening and closing of the VPK 3, Vyk 4, opens and closes the fuel nozzle, etc. In this case, the valve lift height, according to / 2 /, is the maximum possible and is not regulated, the charge of the cylinder 1 at the inlet is determined by the duration of the open state of the VPC 3, the feed mixture in all modes is the same and close to stoichiometric. ICE does not have a throttle. In Fig.3, the fuel nozzle and the spark plug are conventionally not shown.

At full power, the engine works as a classic in the diagram of Figure 2.

In partial load modes - according to the diagram of Figure 4, as follows.

VPK 3 at the inlet stroke closes much earlier than BDC, for example, at point I. With a further movement of the piston down to BDC (angle β ₃ ), the pressure _Pc drops below atmospheric, vacuum piston braking occurs, and the ICE spends energy to overcome the moment, but after the BDC on the piston moving upward, on the compression stroke, to point II (approximately symmetrical point I relative to the BDC), the expended energy returns back (the piston retracts). Thus, ICE does not have pump losses at partial load modes. Pumping losses are typical for ICEs with a throttle.

Throughout the entire speed range of the internal combustion engine and in the entire load range, the engine control system is able to provide optimal valve timing angles.

The desire to bring valves with electromagnets arose for a long time among designers (there are other publications on this subject), but putting it into practice in a serial engine is worth a lot of effort. The fact is that the camshaft used everywhere is simple, cheap and reliable, the cam does not just press and release the valve stem, it “leads” it by gently pressing (opening) and gently releasing (closing), the latter is very important - the valve closes without impact plates on the saddle.

When using a valve actuator with an electromagnet (hereinafter - EMC - an electromagnetic valve), the valve can be quickly opened (unlike the cam) by letting a large current flow into the electromagnet winding, but it is not easy to quickly close it without impact (this is noted in / 2 /), the current the electromagnet is reduced by a special sub-program of the CCMS.

Further, the absence of pumping losses is determined by the fact that the EMC has only two states - fully open - completely closed. However, in a number of partial load modes of the internal combustion engine, it is desirable to be able to not fully open the EMC at the inlet. This introduces turbulence, improves the mixing of air and fuel, facilitates the formation of a layered charge when starting a cold ICE and idling. The force of opening a poppet valve is determined mainly by the force of the return springs and is quite large (reaches 20 kg for the VPC 3, for the VC 4 - even more), when using conventional materials, the volume of the drive solenoid valve is about 0.5 liters - it is bulky. It is also difficult to obtain a high drive frequency (50 Hz or higher). In general, the electromagnetic valve drive is very expensive today, complicated and does not allow partially open states.

The purpose of the invention is due to a slight change in design to make possible the use of low-power EMC.

To do this, in the base part, the classic ICE design with cam camshaft is used, and in the inlet pipe a short distance in front of the inlet valve is an additional damper valve driven by an electromagnet (hereinafter EMZ). The damper easily opens and closes (rising and lowering) without impact and provides a wide variation in the charge of the cylinder with air. Note that from / 3 / it is known the use of an uncontrolled check valve in the intake manifold.

ICE (see Figure 5) contains a cylinder 1 with a piston 2, VPK 3, VOK 4. The latter are driven by cams 5 of the camshaft 6. A piston 2 rotates the crankshaft through a connecting rod 7. EMZ 12 is placed in front of the VPK 3 at a short distance (for example, 1 ... 5 cm), it is a double flap controlled check valve that opens and closes with an electromagnet (EM) under the control of the ACS 11, the same system controls the fuel nozzle 13 and the candle 14.

ICE is shown at the end of the exhaust stroke, piston 2 almost reaches the TDC. A pie chart of the valve timing in partial load mode is shown in FIG. 6.

Let us consider in more detail the design and operation of EMZ 12 (see Fig. 7).

The valve body 13 is mounted in the inlet pipe and contains two transverse partitions 14 spaced apart by a small distance (l = 0.5 ... 3 mm). Partitions have the same coaxial perforation with a maximum element height of h ₁ vertically. A light plate is placed between the partitions - a shutter 15 of thickness S, with the same perforation as the partitions. The damper 15 using the rod 16 can move up and down until it completely overlaps or matches its perforations with perforations of the partitions. The rod is connected with a bipolar cylindrical armature 17 of electromagnets 18-19 and 20-21, where 18, 20 are magnetic circuits, and 19, 21 are coils, respectively. The electromagnet coils are turned on and de-energized via keys 22, 23. If the electromagnet 18-19 is turned on and off - 20-21, the armature 17 and the shutter 15 are in the lower position - the valve is closed (the openings of the partitions 14 are closed by the shutter 15).

If the electromagnet 20-21 is turned on and off - 18-19, the armature 17 and the shutter 15 move up - the valve is open.

In the closed state, the shutter 15 behaves as a check valve for the air flow from left to right, and for the flow of air and exhaust from right to left. In this case, the gas pressure flap is pressed either to the right partition or to the left. According to Fig.7 EMZ 12 has two stable positions (open-closed), it is easy to make intermediate positions (see Fig.7, dotted line), increasing the number of electromagnets and placing them in other planes around the armature. Accordingly, it is necessary to change the magnitude of the displacement of the electromagnets in height - h to the value h / 2 for three electromagnets, h / 3 for four, etc.

The perforation of the shutter 15 and partitions 14 may not be regular and have holes and their groups of unequal area, this causes a turbulence (turbulization) of the air flow at the inlet and improves the carburetion of the working mixture.

The flow area (flow rate) of the EMZ 12 is important. In this regard, the partitions can be located at an angle to the axis OO _{1 of the} inlet pipe (see Fig. 8), consist of several parts, and also have a curved surface, for example, a cylindrical one (see Fig.9).

In the exhaust stroke (see Fig. 6), OFF 4 is open, and VPK 3 and EMZ 12 are closed, the exhaust goes to the exhaust manifold. Short of TDC, VPK 3 begins to open; EMZ 12 is closed. Exhaust gas under excess pressure enters the volume between VPK 3 and EMZ 12 (hereinafter this volume - RP - purge receiver according to / 3 /) and compress the air there (shown by dashed lines and dots).

As the exhaust gas expires, their pressure, _Pgr , drops, the air compressed in the RP expands. acquires speed and displaces the exhaust gas from the RP back to the CS and then, under the action of the ejection effect, into the exhaust manifold, while _Pg falls below atmospheric. At this moment (it can occur both before the TDC and after, depending on the speed and load of the internal combustion engine), the EMZ 12 is opened (it opens instantly and completely), the compressor is purged with air from the inlet pipe in the direction from VPC 3 to VC 4. Further, with closed VC 4 and fully open EMZ 12 and VPC 3, the cylinder is charged. The phases of VPC 3 and VC 4 are unchanged. The angle α ₃ - the beginning of the opening of VPC 3 is chosen to be the largest, so that by the time of the TDC it would be completely open, this ensures the maximum charge of the cylinder at high speeds.

In the partial load modes of the internal combustion engine (see Fig. 6), the EMZ 12 closes long before the BDC of the intake stroke (for example, in position III), this ensures a partial charge, despite the fact that the VPC 3 is still open. Further, with the continuation of the movement of the piston 2 down above it, a certain pressure is created, the internal combustion engine expends energy to overcome the moment. On the movement of the piston 2 up to position IV, the energy expended to overcome the torque is returned (the piston is drawn into the cylinder).

Shortly after the BDC, the intake stroke (the beginning of the compression stroke), as with all classic ICEs, the BCC 3 closes (see angle β ₃ ). The following steps are followed: compression, stroke, release.

It should be noted that in the continuation of the angle φ ₃ in the RP, the pressure is lower than atmospheric, at this time it is advisable to open EMZ 12 for a short time and equalize the pressure to the left and right of the damper (see Fig. 6 the hatched sector φ _у ). The sector φ _у can be located anywhere within the angle φ ₃ (see, for example, sectors φ _у1 , φ _у2 ).

Thus, the disk-shaped VPC 3 and VC 4 located in the cylinder work as compression ones (ensure the retention of the working fluid at high pressures and temperatures), and the controlled one - EMZ 12, provides cylinder charge from minimum to full, and since it is located outside the cylinder, it does not have high demands on preserving compression when exposed to high pressure and temperature. The pressure drop to the left and right of the EMZ is about 0.5 atm. EMZ 12 is made in the form of a light, thin shutter, it works fundamentally without shock when opening and closing, it provides a high frequency of operation, since the mass of the shutter is small, allows intermediate positions and is controlled by an order of magnitude smaller than that of the prototype. Up and down damper stroke is a few millimeters.

It should be noted that in the partial load modes of the internal combustion engine, the energy spent on overcoming the torque at the inlet is not fully returned, the value of “non-return” without taking into account other losses is estimated as the ratio:

Q = V _rp / (V _rp + V _C )

and at minimum loads the internal combustion engine reaches 10%.

In full load mode, the internal combustion engine works as a classic, the maximum charge (see Figure 10) involves the simultaneous closure of VPC 3 and EMZ 12 (or VPC 3 closes before EMZ 12). The moment β _{3 is} set by the cam position and unchanged.

In full load mode, the internal combustion engine can work with forced blowing of high pressure, such as, for example, ICE / 3 /. For this, initially (see Fig. 11), it is established that VPC 3 closes somewhat later than the moment of full charge collection, and EMZ 12 closes at the moment of full charge collection (β ₁₂ ), i.e. earlier VPK 3. Between these moments an angle φ of _{12.3 is formed} . ICE in this mode works as follows.

When the position of the piston 2 is a bit later than the BDC of the intake stroke, when the cylinder charge is full, the EMZ 12 closes and compression begins in the volume V _c + V _rp . When high pressure is reached, for example, P _c = 2 (this happens through an angle φ _12.3 ), the BPC 3 closes, compression continues in the cylinder, and air with a pressure P _p = 2 is stored in the RP. The following are the strokes of the stroke and exhaust. At the end of the exhaust stroke, with closed EMZ 12, the HVC 3 opens, and air from the RP blows the compressor over the angle φ _3.12 in the direction from the HVC 3 to the OFF 4. An increased purge pressure will also be observed in the angle range 2β ₁₂ at a partial load after the point V. To this point P _rn <1 and, as noted above, after the inlet stroke, EMZ 12 must be briefly opened to ensure φ _у (Fig. 6). To do this or not, the ACS 11 decides, depending on the current value of the angle φ ₁₂ .

It should be noted (see Figure 5) that the volume V _{pp should} seem to be minimal in order to reduce the non-return value - Q. But at low V _pp there is little air to purge the COP after the exhaust stroke, and the negative effect on the EMZ 12 is amplified high exhaust gas temperatures.

If V _{rp is} greatly increased (for example, to several volumes of CS, this corresponds to an increase in size L), then the initial principle of the invention will lose its meaning - it will not be possible to provide a small charge, since after the early shutdown of EMZ 12 at a small charge, the cylinder will still gain a full charge from RP through an open air intake complex 3. Of course, for each specific ICE there is its own optimal V _RP , which is determined empirically, but with an average it is comparable with the volume of the combustion chamber:

To start a cold ICE at a low charge, especially at negative external temperatures, is problematic, since at a low charge the pressure of the working mixture at the end of the compression stroke is small - its temperature is low - the charge is poorly ignited by a spark. During a cold start, it is advisable for a short time to give a full charge of air, while forming a layer-by-layer mixture with enrichment in the area of the candle, this task is assigned to the ECC 11.

EMZ provides ample opportunities for the management of internal combustion engines.

1. It makes it possible to open the inlet valve of the cylinder much earlier and thereby obtain high revolutions and torque from the engine.

2. During the purge process, over the valve overlap angle φ _{34, the} EMZ can open and close several times due to low inertia. In a multi-cylinder internal combustion engine in the area of the open exhaust valve, harmonic pressure fluctuations are observed due to exhaust from other cylinders, as well as due to resonant acoustic phenomena in individual sections of the exhaust system. These fluctuations, respectively, change _POG . EMZ is opened at _Pg <1 and closed at _Pg > 1.

3. ICE can be operated as in / 3 /, completely covering the EMZ. This corresponds to turning off the cylinder. Additionally, operation in the vacuum braking mode is possible (see Fig. 13). Here, in the intake stroke, the EMZ is closed (or ajar) - the piston is decelerated by vacuum (the stronger the less the damper is open). Before the BDC, the EMZ intake stroke is fully opened - the cylinder is filled with atmospheric pressure air. After the BDC and closing of the VPC 3, the air is compressed in the cylinder, then, in the stroke of the working stroke, it expands, at the end of which, when the VC 4 is open, the air enters the exhaust pipe, etc. In this mode, accordingly, fuel is not supplied, the braking effect is controlled either by the magnitude of the opening of the EMF, or by the duration of the fully closed state of the EMF per intake stroke.

The vacuum braking mode can also be obtained by repeatedly opening and closing the EMF during the intake stroke.

4. In the partial load mode, the internal combustion engine, as in the prototype / 2 /, can operate in pulse-width modulation mode. In this case, the EMF is fully open for a part of the intake stroke duration (no pumping losses).

A mode of operation with a partially open EMZ is allowed over the entire intake stroke, as when working with a throttle valve (maximum pump losses).

Mixed mode is allowed (small pumping losses). For example, at the intake stroke, first the EMF is fully open (pump losses are minimal, fuel is not supplied), then partially open (air comes in with increased turbulence, fuel is supplied, a stoichiometric mixture is formed), then the EMZ is completely open (fuel is not supplied). Thus, a layer-by-layer mixture is formed when the cylinder is fully charged with air. If at the third stage the shutter is closed, a layered mixture with an incomplete charge of air is formed. EMZ per intake stroke can open fully or partially several times.

Literature

1. V.A. Stukanov. Fundamentals of the theory of automobile engines and automobiles: Textbook. - M .: FORUM: INFRA-M, 2004, p. 55.

2. A. Fomin and A. Vorobyov-Obukhov. Camshaft - retired: The magazine "Behind the Wheel", No. 11, 1998 .; prototype.

3. A.S. USSR No. 889878 class. G02B 29/00.

Claims (13)

1. Four-stroke piston internal combustion engine (ICE), comprising a power system and an ignition system under the control of an integrated engine management system (ACS); a variable valve timing system (SIFG), at least one cylinder, a piston kinematically connected to the crankshaft; a purge valve (KP) located in the inlet pipe; a camshaft, through the cams, leading the inlet and outlet valves located in the cylinder and a purge receiver located between the gearbox and the intake valve, characterized in that to simplify the design and improve the performance of the gearbox, it is opened fully or partially by shifting the shutter, which is driven by a common armature of several electromagnets on KSUD teams with the participation of CIFG the inlet and outlet valves are driven without the participation of SIFG, the inlet valve opens earlier than the gearbox, connecting the combustion chamber to the purge receiver, and closes later, earlier or at the same time after the bottom dead center of the intake stroke. 2. ICE according to claim 1, characterized in that the gearbox includes two stationary transverse partitions with the same coaxial perforation, between which there is a flap with the same perforation, during movement of which (flap) there is a complete or partial overlap of the perforations or their complete coincidence. 3. ICE according to claim 1, characterized in that the common anchor of the electromagnets is cylindrical and has one or more distinct poles in the form of cylinders of larger diameter, which (poles) are positioned opposite the poles of the magnetic circuits of the corresponding included electromagnets:
closed-loop electromagnet,
an electromagnet of a fully open state of the gearbox,
partially open electromagnet KP. 4. ICE according to any one of claims 1 to 3, characterized in that one gearbox is located in the common intake pipe and is used to operate two cylinders, the pistons of which are phase-shifted 360 °. 5. ICE according to claim 1, characterized in that, in order to increase the flow area of the gearbox, the plane of the partitions is set at angles other than 90 ° relative to the axis of the inlet pipe. 6. ICE according to claim 1, characterized in that, in order to increase the flow area of the gearbox, the partitions and the shutter can have a coaxial curved surface (for example, cylindrical). 7. ICE according to claim 1, 2, characterized in that, in order to increase charge turbulization, the transverse partitions and the shutter have groups with different perforation elements area. 8. ICE according to claim 1, characterized in that, in order to organize the optimal purge of the combustion chamber, the moment of opening the gearbox and the flow through it is determined by the engine control system with the participation of SIFG differentially for each specific mode of operation of the engine. 9. ICE according to any one of claims 1 to 3, characterized in that, in order to improve the purge of the combustion chamber, for a period of time when the inlet valve is closed, the gearbox has the ability to open briefly on commands from the ACS. 10. ICE according to any one of claims 1 to 3, characterized in that, in order to improve the purge of the combustion chamber, during the time that the valves of the cylinder cylinder are closed, it has the ability to open and close several times according to the commands of the ACS. 11. ICE according to any one of claims 1 to 3, characterized in that in order to obtain optimal working mixtures in different modes of operation of the engine, during the intake stroke of the gearbox can open for a while, either fully or partially, as well as alternating these two modes in which fuel can either be supplied or not. 12. ICE according to claim 1, characterized in that for organizing the vacuum braking mode of the engine, the gearbox is partially or completely closed at the intake stroke, but for a short time completely opens before closing the intake valve, fuel is not supplied to the cylinder. 13. ICE according to claim 1, characterized in that for organizing the vacuum braking mode by the engine of the gearbox during the intake stroke, it opens and closes several times, fuel is not supplied to the cylinder.

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