FR2772077A1 - INTERNAL COMBUSTION ENGINE - Google Patents

Abstract

Internal combustion engine with at least one cylinder equipped with an intake channel leading to the cylinder and whose intake section is controlled. The intake channel (12) has a valve (18) which controls the intake section. The engine further comprises an upstream valve (13) associated with the valve (16). This upstream valve is controlled according to the engine cycle.

Description

l

  The present invention an internal combustion engine

  dull comprising at least one cylinder with at least one suction channel leading to the cylinder, having a controlled intake section, and the intake channel having at least one valve controlling the intake section. State of the art:

  Internal combustion engines, known in the art,

  try constant displacement curves for the intake valve and the exhaust valve, to control

  gas exchange. The moment of opening and closing

  ture of the valve, the opening time of a valve and the

  valve stroke are periodically constant in each

  as time of the respective cylinder cycle. These support curves

  valve lift are predetermined by contours of

  cams fixed by construction as well as by the height of the cams

  mes and the camshaft permanently driven by the crankshaft

  brequin. These valve lift curves, predetermined

  born by the camshaft represent a compromise between the optimum flow of gas to provide maximum power and losses as reduced as possible, that is to say a good efficiency of the engine when it is operating at partial loads. Such a compromise can however be inconvenient if one wants at the same time to obtain a good maximum power.

  and good performance in the partial load range.

  For high engine power at high speeds, it takes both a long opening time of the valve as well as a large stroke of the valve so that at each suction time, as large a quantity than

  possible fresh gas enters the combustion chamber.

  The disadvantage of such a design of the support control

  pope resides in the pressure losses by throttling at low engine speed and in the partial load range, because for such an operation of the internal combustion engine, the opening times and the stroke of the valve in particular

  of the intake valve are too long or too large

  for the amount of air drawn in, necessary. To allow

  being to nevertheless regulate a correct filling of the combustion chamber, the section of the pipe is reduced

  with a throttle flap, which nevertheless creates

  less pressure drop during gas exchange. The valve overlaps, i.e. opening the intake valve before the exhaust valve is fully closed, are also longer, which creates

  losses by sweeping and for certain function points-

  too much residual gas remains.

aunt in the cylinder.

  To overcome this drawback, systems are known which allow the intake uplift curve to be offset from that of the exhaust. This is to positively influence the torque supplied by the internal combustion engine at the maximum load curve and the residual gas content. As parameters of

  variation to influence the uplift curves

  pope, we have in principle the stroke of the valve, the instant of the opening of the valve and the duration of this opening. In known manner, in particular to reduce the pressure drops, it is known to act on the point of closure of the intake valve. It is for example known to use a variable stroke for the intake valve combined with a continuous phase shift of the intake opening time. We can predict

  for this a complementary eccentric shaft which we de-

  place for example using an electric motor.

  A system is also known for modifying the stroke of the valve rigidly coupled to the opening time. For this, we use in addition to a second intake camshaft rotating at the same rotation speed

  than the first existing camshaft. A transmission by-

  Thanks to an electric motor, it makes it possible to rotate

  the two camshafts in relation to each other.

  The disadvantage of such solutions of a relative construction

  highly complicated is that the modifications to the cylinder head

  are relatively expensive because these modifications require

are trying additional parts.

  There are also known systems intended

  reduce pressure losses using an additional valve

  directly upstream of the intake valve. He has

  for example was proposed a rotary drawer integrated in the tu-

  suction bulb. The air thus passes through a hollow cylinder and arrives through slots in the intake channel. The cylinder is driven by the intake camshaft by a belt and can thus be modified in phase by means of

  additional settings. The result is also a reduction

  pressure losses. The disadvantage is that it does not have to modify the construction of the cylinder head and thus the low

  volume of the suction channel is still slightly depressed

  this ensures good preparation of the mixture of the quantity of fuel injected. However, the downside is

  the possibility of limited modification of this system.

  The present invention aims to develop an internal combustion engine for integrating means

  reducing pressure losses as simply as possible

  ble in existing constructions.

  Advantages of the invention: To this end, the invention relates to an internal combustion engine of the type defined above characterized in that at least one valve is associated with at least one upstream valve, controlled as a function of the engine cycle combustion

internal.

  The internal combustion engine according to the invention has the advantage of allowing with constructive means

  very simple and thus very inexpensive, to realize a sys-

  variable valve to control the admission of a combustion engine

internal bustion.

  As an upstream valve is associated with each support

  intake valve, valve which is preferably made under

  the shape of a drawer or a valve with electromagnetic control

  tick, a load control can be obtained in a simple manner without throttling the internal combustion engine. Upstream valves can be integrated into the internal combustion engine without having to modify the actual construction

  of the breech. In particular thanks to their electric actuation

  These valves are simple and robust, allowing them to operate safely and reliably while using the internal combustion engine as

  defined. In particular, one can very advantageously obtain

  geuse, by a separate control of each upstream valve, a selective filling control per cylinder to act

  directed towards the formation of the mixture (fuel mixture

  rant / combustion air), so that the operation of the internal combustion engine adapts optimally as regards consumption, residual gas content, torque and / or

  the formation of the mixture according to the operating conditions

  current. The upstream valves, provided in addition to the valves

  admission weights can be implemented very advantageously in the form of a separate module which can be easily integrated into or adapted to the engine. Preferably, the upstream valves can be integrated into a suction module associated with the internal combustion engine

  used to supply and distribute the combustion air.

  According to a preferred embodiment of the invention

  tion, the control of the upstream valve is done by an electro-

  engine plug which controls the valves at the same time

  fuel injection and injection into the

  internal bustion. It is thus possible to have an opening or closing command granted to the upstream valves relative to the

  control of the intake and fuel injection valves

  rant, which makes it possible to optimize the operation of the internal combustion engine with relatively reduced means. If the control of the upstream valve is also done in accordance with the various operating parameters of the engine such as the speed, the load, the operating temperature and

  other sizes, so we optimize the consumption

  tion of fuel and engine performance. Upstream valves also controlled by the accelerator pedal allow the driver to control the desired engine power

  without using a throttle valve which deteriorates the return

  engine. Such a control also makes it possible, by the engine electronics, to selectively cut the cylinders in a simple manner, in low load mode

  partial engine loads for very eco-friendly operation

fuel.

  The shutter installations of the upstream valves

  can advantageously be made in the form of a ti-

  flat black activated by electromagnetic means or even as a shutter controlled in rotation. Each embodiment

  is chosen according to the space available or the life

  desired actuation size. An embodiment with a flat drawer offers for example the advantage that the suction channel O10 in the open state of the upstream valve has no resistance creating pressure losses as is the case with the flaps moved in rotation. For such a flap, the axis of rotation remains fully open in the middle

  of the suction channel. An upstream valve with rotation control

  However, this offers the advantage of asking for forces

  lower actuation and operate faster-

  is lying. According to another advantageous development of

  the invention, provision may also be made for continuous actuation

  bare upstream valves. Depending on the voltage applied to

  the electromagnet of the upstream valve, we can have an action-

  continuously with only a partial release of the card

  nal suction. This is how, for example, in

  partial load of the internal combustion engine, you can

  target a partial opening that does not release the entire suction section so that the flow speed of

  the air drawn in does not become too weak.

  According to other advantageous features of the invention: - the upstream valve is controlled independently of the valve with which it is associated;

  - the internal combustion engine has at least two cycles

  lindres each time with a valve and at least one valve

  upstream associated with the valve, the upstream valve of one of the

  lindres being controlled independently of the upstream valve of the other cylinder; - the upstream valve is upstream of the valve; - an injector in the suction channel for the fuel supply and the upstream valve is upstream of the injector; - the control of the upstream valve is done in accordance with a fuel injection control of the internal combustion engine; - the control of the upstream valve is ensured by the engine electronics according to the various engine operating parameters such as the speed, the load, the operating temperature and the position of the accelerator pedal; - the upstream valve is controlled with fuel injection to allow cutting of certain cylinders;

  - the upstream valve is controlled by a no- electric motor

  particularly a stepping motor, a hydraulic motor or a pneumatic motor; - the upstream valve is a flap with a translational movement or a flat drawer actuated by a double-acting electromagnet

  or by a single-acting electromagnet combined with a res-

reminder spell;

  - the upstream valve is a rotary shutter actuated by an electric

  double-acting tro-magnet or by a single-acting electromagnet combined with a return spring;

  - the upstream valve is a translation or rotation shutter ac-

  operated by two oscillating armature electromagnets and res-

  recall spell or iris-like shutter.

  Drawings: The present invention will be described below in more detail with the aid of an example embodiment shown in the accompanying drawings, in which: - Figure 1 is a schematic sectional view of a suction channel of an internal combustion engine, - Figure 2 shows a diagram with different valve actuation timing diagrams for the intake valve and the exhaust valve and the upstream valve, - Figure 3a shows an embodiment d '' an upstream valve with a shutter controlled in translation and a single-acting electromagnet combined with a return spring, - Figure 3b shows an embodiment

  an upstream valve with movable shutter in translation and electro-

  double-acting magnet, - Figure 3c shows an embodiment

  an upstream valve with a movable shutter in translation and induced armature-

  cillant with two electromagnets, - Figure 4a shows an embodiment of an upstream valve with a rotation flap and a single-acting electromagnet combined with a return spring, - Figure 4b shows an embodiment of an upstream valve with rotary shutter and double-acting electromagnet, - Figure 4c shows an embodiment of an upstream valve with rotary shutter and oscillating armature with two electromagnets, - Figure 5 shows an embodiment of 'a

  upstream valve with conical seat closure and electro-

  single-acting magnet combined with a return spring.

  Description of the exemplary embodiments:

  Figure 1 shows in section the position of my-

  stage of an upstream valve 13 according to the invention in a suction channel 12 of an internal combustion engine. There appears a part of the suction channel 12 leading to the combustion chamber 14 of a cylinder; this passage is opened and closed by a known inlet valve 16, with plate 18

  circular, ensuring separation with the combustion chamber

  tion 14. In the direction of flow, directly before the

  intake valve 16, a fuel injector is provided

  rant 20 which injects the fuel directly into the suction channel 12 upstream of the intake valve 16. Upstream of the injector 20 in the flow direction, is

  finds the upstream valve 13 according to the invention; in the realization

  tion shown, this valve has a flat drawer 22 to

  electromagnetic control which can open or close completely

  the opening section of the suction channel 12. The

  flat slide 22 of the upstream valve 13 is pushed into its posi-

  tion of rest by a spiral spring 26 in this embodiment. This rest position is the closed position. It is only by actuating an electromagnet 24 that the flat drawer 22 is moved against the force of the spring

  26 thereby freeing the suction section. For each cy-

  engine key, the upstream valve 13 opens and closes pre-

reference with the maximum stroke.

  Figure 2 shows a diagram showing the diff-

  the various chronograms of an internal combustion engine with four

  be time, representing the actuation of the valves

  exhaust intake and upstream engine valve.

  Reference 40 designates the expansion phase; reference 42 designates the expulsion phase; reference 44 designates the suction phase and reference 46 designates the compression phase

  of a fuel / air mixture in a combustion chamber 14.

  The first line 1 represents the valve lift curves 6, 7 corresponding to the intake valve and the exhaust valve of a cylinder, as a function of time. The height of the valve lifting curve 6 thus qualitatively shows the stroke of a cylinder exhaust valve, not shown; the height of the valve lift curve 7 qualitatively shows the stroke of the intake valve 16. The second line 2 of the diagram shows the valve opening curve 8 of the upstream valve 13 when the internal combustion engine is in full load. It appears that the upstream valve 13 is fully open during the entire duration of opening of the intake valve 16. The slope of the rise in the curve gives the speed of opening and closing of finite duration of the

  upstream valve 13 with electromagnetic control. It is desired-

  ble to have an actuation duration as short as possible

  ble, but which cannot be reduced in any way

  because of the inertia of the moving masses.

  The third line 3 gives as an example a

  curve 9 corresponding to the partial load of the

  internal bustion. For this strategy of early intake shutdown (FAA), the upstream valve 13 is to a large extent opened at the same time as the valve

  16, but it is closed again very quickly-

  after a short time. The fourth line 4 of this slide

  gram shows a strategy for a delayed intake valve closing (FAR) for which the upstream valve 13 is closed only after a selected time after closing the intake valve 16. Finally, the bottom line 5 of the diagram shows another delayed admission opening (OAR) and early admission closing (FAA) strategy. The upstream valve 13 thus opens only at a selected time after the opening of the intake valve 16 and is

  closes already before closing the inlet valve 16.

  All the strategies thus presented can be refined with additional controls for the opening stroke of the upstream valve 13. For example at idle or at low

  loads, it can be very interesting to open only by

  tially the upstream valve 13 and not to release the entire intake section. Similarly, it is possible to have a slower opening speed of the upstream valve 13 in order to synchronize its opening section in this way with the opening stroke of the intake valve 16. Such a control can ensure a regular rise flow velocity

  fresh gas sucked in, thereby reducing turbu-

  lences in the intake channel 12.

  Figures 3a-5 show different embodiments of the upstream valve 13 both from the point of view of

  electromagnetic actuation and the shape of the flap.

  Thus, Figure 3a shows an embodiment

  with a flap 22 movable in translation, actuated by an electric

  single-acting three-magnet 24. A helical spring 26 supports the flap 22 in the form of a flat drawer in the closed position; the electromagnet 24 ensures each time only the opening of the upstream valve 13. When the electromagnet is cut, the

  spring 26 pushes the flat drawer back to the closed position. Vo-

  let 22 itself is a flat drawer guided in a groove 21 transversely to the direction of flow of the channel

suction 12.

  FIG. 3b shows another variant with an embodiment of the upstream valve 13 comprising a flat flap 22 in the form of a drawer as in FIG. 3a but actuated by a double-acting electromagnet 25. The double-acting electromagnet 25 thus ensures both opening and closing

flap 22 of the upstream valve 13.

  Figure 3c shows another variant. The blind

  22 movable in translation according to FIGS. 3a and 3b is ac-

  actuated in this case by two electromagnets 31, 32. The valve of the upstream valve 13 has an oscillating armature 27 at its

  end; this armature can move between the two elect

  three-magnets 31, 32 depending on whether one or the other is powered

in tension.

  Figures 4a-4c show embodiments

  tion in which the upstream valve 13 is provided with a ro-

  23 to continuously open and close the suction channel 12. The rotation point of the flap 23 actuated by a pusher 30 is located on the median longitudinal axis of the suction channel 13. The pusher 30 itself is actuated so electromagnetic either by electromagnets 24 with single effect with return by a helical spring 26 (figure 4a) of electromagnets with double effect (25) (figure 4b) or according to an embodiment with an oscillating armature

  27 movable between the two electromagnets 31, 32 (Figure 4c).

  FIG. 5 finally shows another embodiment.

  In which the upstream valve 13 has a movable cone-shaped closure member 28. In this mode of

  embodiment, the pusher 30 is actuated by an electro-

  magnet 24 single acting and return to the re- position

  pos and closing is ensured by a helical spring 26.

  In this embodiment with a conical seat valve 28, it is also possible to have embodiments with

  double-acting electromagnets 25 for actuating the push-button

  evening 30 or two electromagnets 31, 32 or an oscillating armature 27 movable between the two electromagnets 31, 32 as has

  been shown in Figures 3b, 3c or 4b, 4c.

  As shown by way of example in FIG. 2, the upstream valve 13 opens and closes once for each cycle

  of the internal combustion engine. That means

  fie that the upstream valve 13 is controlled according to the cycle

  of the internal combustion engine. This is a difference if-

  significant compared to a bottleneck, because a vo-

he

  throttle let throttles the gas or air stream that travels

  pours the suction channel or suction tubes of the mo-

  internal combustion tor, regardless of the cycle of

engine operation.

  In the case of an internal combustion engine with several cylinders, each cylinder is preferably equipped with its own upstream valve 13; it is then necessary to provide that the upstream valves 13 of the different cylinders are controlled separately and independently of one another so that the opening and closing of each upstream valve 13 are optimally adapted to the respective time of the corresponding cylinder.

  The inlet valve 16 is preferably actuated

  by mechanical forced guidance by a camshaft.

  This makes it possible to have a robust intake valve 16, which does not risk any damage to the high pressures produced in the combustion chamber 14 of the cylinder. The intake valve 16 provided between the combustion chamber 14 and the

  upstream valve 13 ensures that the high pressures producing

  tes in the combustion chamber 14 cannot act on the upstream valve 13. This allows the adjustable part of the upstream valve 13 to be made as lightly as possible (in the

  exemplary embodiments shown, the upstream valve and the

  let 22 or 23) to allow its simple assembly and to obtain medium restoring forces and high displacement speeds. If the inlet valve 16 which protects the upstream valve 13 did not exist, then the flap 22 or

  23 of the upstream valve 13 is heavy because of the reasons of

  sistance and actuation drives available ac-

  fatally with acceptable means would not possess

  sufficient dynamics for the upstream valve 13.

  Usually each cylinder has an intake valve 16 or more intake valves. In the case

  several intake valves per cylinder, it is possible to

  ble to associate with each inlet valve 16 a valve

  upstream 13 independent; we can also for each cylinder

  dre provide an upstream valve 13, common to several valves

admission 16.

Claims (8)

R E V E N D I C A T IONS   1) Internal combustion engine comprising at least one cylinder   dre with at least one suction channel leading to the cylinder   dre, having a controlled intake section, and the intake channel having at least one valve controlling the intake section, characterized in that at least this valve (16) is associated with at least one valve   upstream (13), controlled according to the cycle of the internal bustion.   2) Motor according to claim 1, characterized in that   the upstream valve (13) is an electrically operated slide valve tromagnetic.   3) Motor according to claim 1, characterized in that   the upstream valve (13) is a shutter valve with electro- magnetic.   ) Motor according to any one of the preceding claims. teeth, characterized in that   the upstream valve (13) is controlled independently of the support   pope (16) with which she is associated.    ) Motor according to claim 1, characterized in that   the internal combustion engine has at least two cylinders   dres each time with a valve (16) and at least one upstream valve (13) associated with the valve (16), the upstream valve (13) of one of the cylinders being controlled independently of the valve upstream (13) of the other cylinder.   6) Motor according to claim 1, characterized in that   the upstream valve (13) is upstream of the valve (16).   7) Engine according to claim 1, characterized by an injector (20) in the suction channel (12) for the fuel supply and the upstream valve (13) is upstream of the injector (20). ) Motor according to claim 5, characterized in that the control of the upstream valve (13) is done in accordance with a   fuel injection control of the internal combustion engine   dull. 9) Engine according to claim 1, characterized in that the control of the upstream valve (13) is provided by the engine electronics according to the various engine operating parameters such as speed, load, operating temperature and the position of the accelerator pedal. ) Motor according to claim 5, characterized in that   the upstream valve (13) is controlled with fuel injection   rant to allow cutting certain cylinders (14).   11) Motor according to any one of claims 1 to 10,   characterized in that the upstream valve (13) is controlled by an electric motor, in particular a stepping motor, a hydraulic motor or a pneumatic motor.   12) Motor according to claim 1, characterized in that the upstream valve (13) is a shutter with translational movement or flat drawer (22) actuated by a double electromagnet   effect (25) or by a single-effect electromagnet (24) linked to a return spring (26).   13) Motor according to claim 1, characterized in that the upstream valve (13) is a rotary shutter (23) actuated by a double-acting electromagnet (25) or by a combined single-acting electromagnet (24) to a return spring (26). 14) Motor according to claim 1, characterized in that the upstream valve (13) is a flap (22, 23) in translation or   rotation actuated by two electromagnets (27) with oscillating armature and return spring (26).    ) Motor according to claim 1, characterized in that the upstream valve (13) comprises a shutter in the form of an iris diaphragm or a shutter member with conical seat (28).