FR2534971A1 - METHOD AND DEVICE FOR SUPPLYING AN INTERNAL COMBUSTION ENGINE BY EXHAUST GAS TURBOCHARGER - Google Patents

Abstract

The invention relates to a method and a device for supercharging an internal combustion engine by an exhaust gas turbocharger. IN THIS DEVICE EQUIPPING AN INTERNAL COMBUSTION ENGINE WITH SEVERAL CYLINDERS EQUIPPED WITH A COMBINED SUPERCHARGER POWERED BY A TURBOCHARGER 5, 7 AND INTAKES 9, 8 AND EXHAUST 2, 3, 4 SUITABLE TO OSCILLATE, THE SAID PARTS D THE INTAKE AND EXHAUST ARE CONNECTED BY A LINK 13 TO AN OSCILLATING SYSTEM CAPABLE OF RESONTING AND WHOSE OWN FREQUENCY CAUSING THE OVERFURNING IS CLOSE TO THE EXCITATION FREQUENCY. AN ISOLATION BODY 14 INCORPORATED IN LINK 13 CONNECTS THE INTAKE AND EXHAUST COMPONENTS OF THE OSCILLATING SYSTEM WHEN THE PRESSURE IS GREATER ON THE INLET SIDE THAN THE EXHAUST SIDE. APPLICATION TO INTERNAL COMBUSTION ENGINES WITH COMBINED SUPERCHARGING.

Description

The present invention relates to a method of supercharging a

  an exhaust gas turbocharger internal combustion engine or engine, using a compressor mounted on the intake side and a turbine located on the exhaust side, and taking advantage of the gaseous oscillations

by means of an oscillating system.

  Turbocharging is currently by far the best known way to increase

  the specific power of an internal combustion engine.

  However, the different absorption characteristics of the turbocharger and the four-stroke internal combustion engine raise very complex adaptation problems, particularly when the internal combustion engine has to be designed for the widest possible range of high average pressures. As is necessary for modern vehicle engines Therefore, any adaptation of a turbocharger to a four-stroke vehicle engine is ultimately a compromise between optimum operating values at a time of

  chosen operation and a field or operating range

  as much as possible.

  A whole series of measures is known to overcome

  these difficulties and to widen as much as possible the useful operating range of supercharged

turbochargers.

  For example, for small engines, it is generally common to have a relief valve downstream of the compressor or upstream of the turbines to regulate

  the maximum pressure of supraimentation.

  It is also known to combine the supercharging

  turbocharger to a supercharging obtained by

  a system of resonance In what is called the "overeating"

  resonance system, systems are used which

  by oscillations of fresh and harmonized gases

  depending on the resonance, contain resonance tubes

  The latter then form an oscillating system whose specific number of oscillations can be well determined. The principle of resonance boosting can be applied in isolation, or it can be precisely combined with a supercharging system.

  turbocharger to constitute what is called a "supercharger"

  When this oscillating arrangement is interposed between the turbocharger or the air supply duct and the cylinder and when, as a result of the piston stroke during operation of the engine during successive suction periods, it is excited at a frequency close to its specific number of oscillations, a resonance occurs and this causes amplified pressure oscillations by virtue of which, under the action of the overpressures due to the oscillations and occurring at a moment considered

  When the intake valve is closed, the rate of return

  The cylinders can be significantly improved in a desired range of angular velocities, compared with internal combustion engines which do not have such a resonance boost. More detailed considerations in this regard have been published for example in the journal "IMTZ Notortechnische Zeitschrift ", No. 32 (1971), pages

  368 to 373 and 39 (1978), pages 447 to 451.

  In addition to such devices placed on the intake side and equipped with an oscillating system harmonized according to the resonance, the provision of an oscillating system quoted exhaust is, for example, known from the document DE-A-2 914 691. The method described in this document provides for the separation of the absorption or the efficiency of a four-engine

  time and a turbocharger, so that the conditions

  operating conditions of the latter are close to those of the pure and simple principle of a gas turbine

  cause this separation, a connecting duct

  tion) connects the intake manifold, downstream of the compressor,

  at the exhaust manifold upstream of the turbine

  junction box is connected parallel to the motor

  valve incorporated in this connecting duct makes it possible to

  the current of air flowing through it Taking advantage of the pulsation energy generated by the movement of the engine gases and originating on the one hand from the pressure variations * of the supercharging air on the suction side and, on the other hand, on the other hand, pressure variations of the exhaust system on the exhaust side, the connecting duct must cause a pressure difference so great that a large amount of air must flow through this connecting duct during operation. under partial load, and this even when the average pressure upstream of the junction conduit is lower than the average pressure prevailing downstream thereof It allows to obtain, in addition to an increase in air pressure supercharged, an improvement in the acceleration behavior of a motor thus equipped, preferably in the operating range under partial load in which it is to be expected a need for

maximum air.

  A similar technical process of supercharging, described in a review "Entropy", No. 48 (1972), pages 5 to 12, provides in addition to have a combustion chamber in

the mentioned connecting duct.

  The known resonance systems situated on the charge air side, in which the cyclically induced suction strokes cause a wave-in the intake system in the case of resonance, nevertheless have disadvantages which oppose them. wide use Excitation energy absorbs work developed by the movement of gases, which increases fuel consumption In many cases of use (number of cylinders), the pressure amplitudes that can be created are too small for efficient over-feeding can be guaranteed The width of the effective frequency band is relatively small On the other hand, resonance systems placed on the exhaust side do not

  no improvement and even exert negative effects.

  In addition, in general, the arrangement and design of a resonance system always constitutes a compromise between optimum performance,

  acceptable dimensions of components and flow losses

  In this case, the question of sizing becomes all the more critical.

  that the spectrum of the resonant frequency is low.

  It is therefore an object of the invention, in comparison with known supercharging systems, to increase the pressure amplitudes on the intake side (and thus the supercharging effect), to reduce the work absorption of the movement of gases to excitation, and dissociate the turbocharger from the engine so that it can operate in a more favorable operating range. For this purpose, the method according to the invention is characterized by the fact that the admission organs and the

  exhaust components of the engine are connected by a connection for

  to kill an oscillating system capable of resonating when the pressure

  downstream of the compressor is greater than the pressure

  prevailing upstream of the turbine.

  According to the invention, a device for implementing this method, equipping a piston engine

  internal combustion engine with multiple cylinders,

  an exhaust gas turbocharger and comprising intake members, connecting members and escapement members capable of oscillating, is characterized by

  the fact that intake organs, escape

  as well as a connection between them) are harmonized according to an oscillating system whose frequency causing the supercharging is close to the excitation frequency; and in that there is incorporated in said connection an isolating member which connects the intake components and the exhaust components of the oscillating system when the pressure on the intake side is

  stronger than that prevailing on the exhaust side.

  The use, proposed by the invention, of the exhaust side to form the resonance oscillating circuit makes it possible to obtain considerable advantages. Firstly, the above-mentioned dimensioning problem is generally water-softened. excitation of a standing wave concerns a place in which it is

  available in large quantities and in a cyclical succession

  that can be used in an appropriate grouping.

  In the exhaust system, pressure pulsations (which are otherwise not used) to excite the oscillation system on the intake side provide greater amplitudes of pressure. The same effect causes a lowering of the pressure in the zone between the pulsations, which again reduces the work caused by the movement of the gases, thus also the fuel consumption At the same time, the absorption characteristics of the engine and the turbocharger are dissociated, with the

benefits that entails.

  The isolation device may consist of a non-return valve which is mounted in the connection in such a way that it only allows a flow on the intake side

  at the exhaust side In this case, the turbocharger

  is completely free and will always have an optimum degree of efficiency in the operating state

stationary.

  However, when it is desired to return the exhaust gases in circulation because of the quality of these exhaust fumes at very low load and / or to improve the cold start of the engine, it is advisable to realize the engine body. insulation in the form of an adjustable flap whose position can be adjusted according to the load,

  the power and speed of rotation of the combustion engine

internally.

  The invention will now be described in more detail with reference to the accompanying drawings by way of non-limiting examples and in which FIG. 1 schematically illustrates an engine

  six-cylinder in-line equipped with a supercharger-

combined;

  Figure 2 shows an analogous representation

  FIG. 1 illustrates a four-cylinder engine. FIG. 3 illustrates by a similar representation a five-cylinder engine.

  Figures 4a and 4b are each a representation of

  fragmentary section corresponding to the preceding figures, to illustrate the possibility of mounting the charge air cooler-; and Figure 5 is again a representation

  similar to Figures 1 to 3, showing an eight-cylinder engine

  in V to highlight the application of the inven-

  to engines with larger numbers of cylinders in

arranging the device in duplicate.

  FIG. 1 schematically illustrates a six-cylinder engine Cylinders 1a, 1b, 1c, 1d, 1c located in the engine block, not shown in detail, each have an intake valve and an exhaust valve * not shown in FIG. According to the conventional mode of operation of an engine of this type, the operating cycle is such that the rollers 1a, 1b, 1c or 1d, the, lf follow each other with a crank angle of 240 and that there is enter

  these two groups a crank angle difference of 120 '.

  This arrangement causes a distribution of the admission organs

  and exhaust components in two groups, as shown in Figure 1 The exhaust valves of the

  group of cylinders 1a to 1c each open

  An analogous arrangement is provided for the exhaust valves of the group of cylinders 1d to 1f, which open out through exhaust channels 2 into the exhaust manifold 2 into a common exhaust manifold 3.

  an exhaust manifold 3 associated therewith.

  From each of these two manifolds 3, an exhaust pipe 4 directs the exhaust gases to an exhaust gas turbine before they are discharged into

  This turbine 5 driven by the exhaust gases

  7 leads to a compressor 7 via a driving link 6 '.

  5 and the compressor 7 together form the turbocompres-

the motor shown.

  In a manner corresponding to the disposition of the exhaust side, the intake valves of the group of cylinders 1a to 1c each open through an intake channel

  8 in a common resonance tank 9 and, analogously,

  the intake ducts 8 of the cylinders 1d to 1f

  The two resonance chambers 9 are each connected by a resonance tube 10 to a compensation tank 11 which is connected in turn by means of a conduit 12 for supplying the reactor. air, at the outlet side of the compressor 7 of the turbocharger The two resonance tanks 9 located on the intake side are, as

  it appears from Figure 1, connected by conduits of rods

  13 (arranged in a cross) to the exhaust manifolds 3

  In this connection 13 between the intake side and the exhaust side, there are incorporated isolation members (in the form of nonreturn valves 14 in the example under consideration) which block

  flow from the exhaust side to the intake side.

  The mode of operation and the action exerted by the turbocharger 5, 7 described above can be

presuppositions known.

  The resonant oscillation circuit, associated with the supplementary resonance boost, is formed by the two resonance tubes 10, the compensation tank 11, the resonance chambers 9 and the intake-side inlet channels 8, and ue through the junction tubes 13

  and exhaust-side organs, escape channels,

  2, the exhaust manifolds 3 and the

exhaust pipes 4.

  So, this oscillating system includes as well

  of the organs on the intake side that organs on the

  The oscillating system is set so that its natural frequency is within a desired range of angular velocities.

  when the link 13 is open.

  said engine, the gaseous oscillations are

  caused by escapement, succeeding one another cyclically

  1c or 1d to 1f and they produce the supercharging at the end of the suction cycles of the intake sides of the id cylinders at If or the at 1c, connected by

the link 13.

  In Figures 2 and 3 which respectively illustrate

  By the same kind of representations as in FIG. 1, a four-cylinder in-line engine and a five-cylinder in-line engine, the components of the oscillating system are shown adapted to the operating mode of these engines, in particular to their devices. ignition, controls

  their valves and the overlapping of their vacuum cycles.

  In this case, the oscillating system comprises the resonance tank 9 itself placed downstream of the duct 12 for supplying air from the compressor.

  7 to said resonance tank 9; on the admission side, this system

  There are four (FIG. 2) or five (FIG. 3) inlet channels 8 connecting this tank 9 to the cylinders 1a to 1d or 1a; on the exhaust side, it comprises an exhaust manifold 3 into which the four or five exhaust ducts 2 of the cylinders 1a to 1c or 1a, the exhaust pipe 4 and the duct 13 which connects the resonance tank 9 at the collector 3 and in which is again incorporated an isolation member 14,

for example a check valve.

  Again, this oscillating system is set so that its natural frequency is in a desired range of angular velocities of the engine when the link 13 is open. The gaseous oscillations are caused.

  by the exhaust thrusts that follow one another cyclically.

  The duct 12 for supplying the air must be designed so that its natural frequency is not in the frequency

  excitation determined by the motor.

  The aforementioned devices can be supplemented at any time by a charge air cooler In a six-cylinder engine according to the example of Figure 1, and as shown in Figure 4 a,

  a cooler 15 of this type is conveniently connected directly

  on the duct 12 supplying air, upstream of the compensation vessel 11 In the exemplary embodiments according to FIGS. 2 and 3, and as shown in FIG. 4 b, this cooler is rationally mounted in said FIG. 5 illustrates, by way of example, an embodiment according to the invention of machines or internal combustion engines equipped with a number of cylinders.

  higher than the examples in Figures 1 to 3.

  tion is based in each case on a multiplication (in particular a doubling) of the devices according to Figures 1 to 3 above, in which case however it is generally provided for each engine a single turbocharger, that is to say a only compressor 7 and a single turbine 5 which drive

  corresponding torque or power distributions.

  This multiplication comes out in detail from the eight-speed engine

  cylinders shown in Figure 5, which comprises a double

  of the device illustrated in Figure 2 for an engine

  four-cylinder In this case too, the identical

  In the same way, according to the invention, it is possible to obtain ten-cylinder engines by a doubling of the five-cylinder engine shown in FIG. 3, and twelve-cylinder engines by a doubling of the engine to six

cylinders of Figure 1.

  In any case, the isolation member (s) 14 may be made in the form of simple nonreturn valves which, as mentioned before, are incorporated in the connection between the intake side and the exhaust side.

  in order to allow only a flow on the permissible side

  From the technical point of view, it should be noted that the flow losses are kept very low in the isolating member 140. According to an improvement of the invention, if a certain recirculation of the gases occurs. is desirable because of the quality of the exhaust gas at very low load and / or to improve the cold start properties, the or each of the isolation members 14 may also consist

  in a controllable flap The adjustment of such an isolating member

  can then take place according to different

  engine meters, for example injection pumps, the position of the adjusting rods and / or the engine rotation speed, the temperature of the exhaust gas, etc. It goes without saying that many modifications can be made to the described method and device.

  and shown without departing from the scope of the invention.

Claims (5)

CLAIM $   1 Supercharging method of a combustion engine   internal combustion exhaust turbocharger, in   using a compressor located on the intake side and a   the exhaust system, and taking advantage of the gaseous oscillations by means of an oscillating system, characterized by the fact that the intake members (9,8) and the exhaust members (2, 3, 4) ) of the motor are connected by a link (13) to form a resonant oscillating system (2, 3, 4, e, 9, 13) when the pressure prevailing downstream of the compressor (7) is greater   the pressure prevailing upstream of the turbine (5).   2 Apparatus for implementing the method according to claim 1, equipping a machine or piston engine with internal combustion provided with several cylinders, supercharged by exhaust gas turbocharger and comprising intake members, connecting members and exhaust members adapted to oscillate, characterized in that intake members (11, 10, 9, 8), exhaust members (2, 3, 4) and a link ( 13) between these are set according to an oscillating system   (2,3,4,8,9,13) whose own frequency causes the over-   feeding is close to the frequency of exeitation; and in that connection there is incorporated an isolating member (14) which connects the intake components (9,8) and the exhaust components (2,3,4) of the oscillating system when the pressure on the admission side is more   large than that prevailing of the exhaust ect.   3 Device according to claim 2, characterized in that the isolation member (14) is a valve check.   4 Device according to claim 2, cara   the fact that the isolating member is in the form of an adjustable flap whose position can be adjusted according to the load, the power and the   rotational speed of the internal combustion engine.   Device according to one of Claims 2 to 4, characterized in that the   an air cooler (15) of surali- mentation.   6 Device according to any one of the   2 to 5, characterized in that the isolating member   (14) is controlled in such a way that a certain amount of exhaust gas is recirculated   the operating range under partial load.