FR2468747A1 - IMPROVEMENTS IN THE OPERATION OF AUTOMATIC COMBUSTION ENGINES - Google Patents

Abstract

Operating method of a self-igniting internal combustion engine provided with a dynamic pressure supercharged exhaust gas turbocharger, including the steering device, connected in the gas turbine upstream of the turbine wheel in the direction of exhaust gas, can be adjusted to vary the passage section. The method is characterized in that the passage section QL of the directing device 12 is adjusted so that: a. That in the lower ULB load range this section be brought to a maximum size QLmax; b. That in the mean range of MLB load it be brought to a minimum quantity QLmin; and c. That in the upper load range OLB it is again brought to the maximum magnitude QLmax and that in addition, in this load range, the moment of injection is simultaneously delayed relative to that of the average load range MLB .

Description

The invention relates to a method of operating

  an internal combustion engine to autoallumaae

  equipped with a supercharged exhaust turbocharger

  dynamic pressure system, including the direct

  connected in the gas turbine upstream of the turbine wheel in the direction of the exhaust gas, can be

  to vary the passage section.

  CH Patent No. 107,453 shows, for example,

  FIG. 4 shows an internal combustion engine comprising

  an exhaust turbocharger supercharged

  dynamic pressure, in which the flow section

  flow of the exhaust gas turbine can be modified by a regulator. This adjustment member is part of an adjusting device and is coupled on the one hand

  a motor rotation speed regulator with inter-

  position of a linkage, and secondly to a regulator of

  pressure acting by the pressure of the supercharger

  tion. The rotational speed regulator brings the regulator to a coarse adjustment position in which the inflow section of the exhaust gas turbine takes at any time a determined quantity corresponding to a determined rotational speed, so that the increase

  or the decrease in the speed of rotation

  to increase or decrease the

  flow, while the regulator reacts to the supercharging pressure brings the regulating member to its extreme position corresponding each time to the pressure

  momentary charge air. In a range of

  In this way, according to the specific design of the engine, a specific inflow section of the exhaust gas turbine of suitable size is released, so that in this range of loads, by virtue of the amount of exhaust gas existing and from the resulting energy of the exhaust gases, a determined supercharging air pressure is established. However, in this earlier publication, nothing is said about the

  behavior of the internal combustion engine with regard to

  fuel consumption, or a specific control mode of the influx section to obtain a

minimum fuel consumption.

  On the contrary, this invention relates to a method of operating an internal combustion engine

  auto-ignition system of the type defined above, which makes it possible

  keep optimum fuel consumption over the entire

  range of loads without exceeding the maximum pressure of

mage set for full charge.

  According to the invention, this object is reached

  thanks to the fact that the passage section of the dis-

  director so that (a) only in the lower range

  this section is brought to a maximum size, (b) the average load range is brought to a minimum and (c) in the upper load range is again brought to the maximum size. and that furthermore, in this load range, the moment of the injection is simultaneously delayed

  relative to that of the average load range.

  Other embodiments are described in detail below.

  Thanks to the application of the method according to the invention, a considerably lower fuel consumption can be obtained than that of an internal combustion engine which operates with a non-adjustable passage section of the steering device of the turbocharger high pressure turbine. exhaust gas. For the reduction of the fuel consumption in the higher load range, the inclusion of the injection pump in the process according to the invention, with the possibility of varying the time of the injection, is of decisive importance. The reduction of fuel consumption,

  and therefore the noticeable decrease in operating expenditure

  resulting from this, are achieved to a large extent in practice by rational use of the groups that exist in the

2468747-

  internal combustion, and without inadmissibly exceeding certain limit values set by

  so that to apply the present process of

  In existing assemblies, it is sufficient to reduce the transformation of the control and the injection pump. The following is more specifically described:

  method of operation provided by the invention for a

  self-igniting internal combustion engine of the type defined above, with reference to a two-stage exhaust gas turbocharger shown schematically in FIG. 1 of the drawings, and various operating diagrams. On the drawings:

  Figure 1 schematically shows a turbo-

  two-stage exhaust gas compressor comprising different devices for driving the operating method;

  FIG. 2 is a diagram showing the in-

  FIG. 3 is a diagram showing the power domains of the internal combustion engine and on which the power in percentage has been plotted as abscissa, also serving as abscissa for the other diagrams represented. by Figures 3 to 7; Figure 4 is a diagram showing sectional variations of the director device in the execution of the operating method; Fig. 5 is a diagram showing the variation of the ignition pressure in the present process; Figure 6 is a diagram showing

  the variation of the proportion of combustion air in this pro-

  sold; FIG. 7 is a diagram showing the

  actual fuel consumption curve in the pre-

process of operation.

  The procedure of the invention according to the invention is applicable to internal combustion engines equipped with a single or multi-stage exhaust gas turbocharger, but which is explained here in connection with a two-stage exhaust turbocharger as this supercharging mode is more applicable in self-igniting internal combustion engines, particularly in diesel engines with

major power.

  The two-stage exhaust turbocharger shown in FIG.

  high pressure 1 with high pressure turbine 2 and

  high pressure pressure washer 3 driven by the turbine, and a low pressure stage 4 with a low pressure turbine 5

  and low pressure compressor 6 driven thereby.

  The high pressure turbine 2 and the low pressure turbine

  5 are axial flow turbines and are arranged coaxially side by side. The high pressure turbine 2 and the high pressure compressor 3 of the high pressure stage 1 on the one hand, and the low pressure turbine and the low pressure compressor 6 of the low pressure stage 4, on the other hand, are placed on respective shafts 7 and 8 aligned axially with each other; in addition, the outlet of the exhaust gases 9 of the high-pressure turbine 2 is arranged so as to open directly, without the interposition of a deflection device, into the exhaust gas inlet 10 of the low-pressure turbine

  pressure rotating in opposite direction. The high pressure turbine

  2 of the high pressure stage 1 is formed of a turbine wheel 12, a director device 12 and a supply volute 13 with suction pipe 14 which, not shown and in it - even known, is connected directly by a flange to the exhaust manifold of the

  internal combustion engine with self-ignition, not shown

  felt no more. The high-pressure turbine 2 of the high-pressure stage 1 is supplied in service by the exhaust gases of the engine indicated by the arrow 15 and aui, coming from the exhaust manifold, are introduced through the intake manifold 14 in the supply volute 13 of the high-pressure turbine 2. The latter serves to uniformly bring the incoming gases to the blades 16 distributed around the entire periphery of the wheel 11 of the high-pressure turbine 2, and also to ensure a great exhaust velocity. The high-pressure compressor 3 is formed of a radial compressor wheel 17 with blades 18

  suitably arranged, and a compressor compressor cover

  dial 19, provided with a discharge volute 20 and which is connected with

  corded on the inlet side to a feed channel 22 feeding - according to the arrow 21 - air precompressed to the compressor wheel 17, and the outlet side, through an outlet pipe 23, to a pipe 24 which can be brought to the combustion chambers of the engine, in the direction of the arrow, the supercharged air supercharged in the high pressure compressor 3. The pipe 24 is connected by

  not shown, via a cooling device

  also not represented, to the corresponding admissions

the engine cylinders.

  The exhaust gas outlet 9 of the high pressure turbine is connected, via

  of a transfer channel 25 at the inlet of the exhaust gas

  10 of the low pressure turbine 5 which is formed of a wheel 26 with vanes 27 uniformly distributed around the circumference and axially traversed, and a housing of

  axial compressor 28 with discharge volute 29. The cartridge

  axial compressor 28 is connected in a manner that is not

  sent through an outlet pipe 30 to the exhaust of the internal combustion engine, to which the exhaust gases are fed, in the direction of the arrow 31, after their

  kinetic energy has been used completely.

  The low pressure compressor 6 comprises a radial compressor wheel 32 provided with blades 33 of suitable structure, and a radial compressor housing 34 in the form of a volute. The charge air is sucked by the low pressure compressor 6 in the direction of the arrow 35, through a pot 36 with silencer and

  air filter, it is precompressed by the compression wheel.

  32 on the outlet side of the housing 34, in the direction of the arrow 38, through a pipe 37, to a cooler 39. The latter is connected to the side of the outlet to the air intake duct leading to the compressor

at high pressure 3.

  In the exhaust gas turbocharger

  described above, the use of exhaust energy, as well as the compression of

  of the charge air, are carried out in two stages.

  The exhaust gas coming from the internal combustion engine

  in the direction of arrow 15, by the exhaust manifold

  first time it is used in the high-pressure stage 1 and then brought, with a view to a new

  low pressure stage 4. Exhaust gases

  sent to the high-pressure turbine 2

  the high-pressure stage lose in this stage a pre-

  part of their energy, and at the output of it, they enter directly into the transfer channel 25 which widens conically, then into the input channel

  exhaust gases 10 of the low pressure stage 4.

  Since the high-pressure stage 1 and the low-pressure stage 4 are adjacent by the front sides of their turbines 2, 5, the path that the exhaust gas must accomplish between the two turbine stages is very short. . Conical widening of the transfer channel serves to adapt the flow sections to the pressure ratios of the exhaust gas. The turbine wheel 26 is lined at its circumference with blades 27 which are directed in the opposite direction to that of the blades 16 of the turbine wheel 11 of the high-pressure stage, and are inclined upside down flow of the exhaust gas, so that the direction of operation of the high pressure stage is opposite to that of the low pressure stage; -moreover, thanks to

  that provision, the direction printed on the exhaust gas

  The output of the high-pressure turbine 2 is exactly that which is desirable at the inlet of the low-pressure turbine 5. Since there is no change in

  direction and that the construction is extremely

  combrante, power losses in the region between the two turbine stages are removed almost completely. In the low pressure turbine 5 of the low pressure stage 4, the flow energy of the introduced gases is converted by the turbine wheel 26 into movement energy and then the exhaust gases are fed in the direction from arrow 31, going through

  the exhaust volute 29, at the exhaust pipe not re-

  present. The energy of movement of the turbine at low

  pressure 5 is used, in the low pres-

  6 rigidly coupled, to precompress. the supercharging air sucked in the direction of the arrow 35. The pre-compressed supercharging air is fed through the pipe 37 to the aftercooler 39, where it is cooled, and then it is fed through the pipe 22 to the high-pressure compressor.

  pressure 3 of the high pressure stage 1. This air of super-

  The precompressed feed is further compressed in the high-pressure compressor 3 by the radial compressor wheel 17 and then by the exhaust volute 20 and the outlet pipe 23 of the radial compressor housing 19, as well as through the pipe 24, it is brought to the cylinders of the

internal combustion engine.

  In an exhaust gas turbocharger

  of this kind, provided that the passage section of the steering device 12 is constant throughout the range of loads - in accordance with dash 40 of Figure 4 - and that the moment of injection remains the same throughout the range As shown in dash 41 of FIG. 2, the function curves shown in phantom in FIGS. 5, 6 and 7, namely 42 for ignition pressure P (FIG. 5), 43 for FIG. air ratio

  oxidizer Av (Figure 6) and 44 for the consumption

  fective fuel be (Figure 7). In Figure 3, we have

  indicated the load ranges of the internal combustion engine; a lower domain (ULB) is defined as the range between 0 and about 15% of the full load, in which the motor operates at a

  average effective pressure MS of about 4.5 to 5.5 bar.

  The average load domain (MLB) is defined as that between about 15% and about 80% of full load power, while the upper load domain (OLB) is defined by the domain greater than about 80%

  power in full charge. In the case where the

  flow rate of the turbine steering device 12

  at high pressure 2 of the high pressure stage 1 of the turbo

  exhaust gas compressor remains unchanged in-all

  load range, in accordance with paragraph 40 of the

  4, and o the moment of injection remains as

  ge in the entire range of loads according to dash 41 of Figure 2, it establishes in full load supercharger air pressure higher than that which would be

  necessary for the most fuel-efficient

  and this higher supercharger air pressure

  This entails, particularly in the upper load area OLB, a relatively high ratio of combustion air Xv. disadvantageous for the consumption of

  fuel, as shown in dash 43 of Figure 6.

  The ignition pressure PZ increases constantly, in accordance with

  in dash 42 of Figure 5, starting from a minimum,

  up to a maximum set by engine construction.

  By virtue of the characteristic curves shown in FIGS. 5 and 6, 42 for the ignition pressure PZ and 43 for the combustion air ratio Av, there is a characteristic fuel consumption, be, corresponding to the dashed curve 44. This fuel consumption results from the thermodynamic values that are established during the operating process, and in particular the ratio between the ignition pressure Pz and the average effective pressure Pme. this fuel consumption, represented by curve 44

  of Figure 7, by appropriate measures. For re-

  to solve this problem, we took in the combustion engine

  the following provisions, explained with reference

in Figure 1.

  The steering device 12 of the turbine

  at high pressure 2 of the high pressure stage 1 of the turbo

  exhaust gas compressor is designed in the form of

  ble, so that one can vary its effective passage section QL. To this adjustable steering device 12 is added an adjusting device 45 whose adjustment signal can be applied to the steering device 12 for

  adjust it, as shown schematically in line 46.

  For its part, the adjustment device 45 responds to

  The control device 47 itself responds to two different signals which are sent to it at two inputs, a first input 49 and a second input 50. first inlet 49 is connected by a channel 52 to a device for measuring the supercharging air pressure 51. This measuring device 51 is connected on the input side, Dar a measuring tube 53, to the pipe 24 by which the highly compressed supercharging air exiting the high pressure compressor 3 can be brought to the different cylinders of the engine. The measuring device 51 captures the existing boost air pressure and transforms it into a corresponding electrical signal which

  is sent to the control device 47 via the channel 52.

  By its second input, the control device 47 is

  connected to a guide linkage 54 schematically shown

  which, influenced on the side of entry by a regular

  55, serves to adjust the piston of an injection pump

  fueling 56 following. The latter is connected in a manner not shown, by its suction pipe 57 to a fuel tank, and by its discharge pipe 58 to a high pressure accumulator, not shown either, from which hoses are known in a known manner. of fuel that go to the engine cylinder injection valves. The control piston of the pump

  fuel injection device 56 comprises, in a non-recom-

  presented, an oblique control edge by means of the-

  which, in the upper range of OLB loads - see

  figure 3 - the moment of injection can be delayed

  latively to that of the lower and middle domains of

  charge, in accordance with solid line 57 of FIG.

  The guide linkage 54 starts, according to this shift and its momentary position, signals which can be

  sent via a channel 59 to the second input 50 of the

control system 47.

  By taking advantage of the arrangements described above, it is possible to apply, in order to obtain a lower fuel consumption, the operating method of the engine according to the invention, described hereinafter. The flow section QL of the adjustable steering device 12 provided in the high pressure turbine 2 of the high pressure stage 1 of the turbocharger is adjusted so that (a) in the lower load range ULB - corresponding to FIG. - it is brought to the maximum section QLmax - see the solid line 60 of Figure 4 - (b), that in the range

  MLB load average it is brought to a minimum section

  QLmin (about 60 to 70% of the maximum section of

  passage QLmax - see solid line 61 in Figure 4 -

  and (c) that in the upper load range OLB, it is fed to the maximum passage section Q Lmax, see

solid line 62 of FIG.

  In addition, in the upper load range OLB, the moment of the injection is simultaneously delayed relative to the average load range, as indicated by the oblique solid line 63 in FIG. 2. The passage of a section of FIG. switching to another of the directing device 12 preferably takes place continuously.

  in order to avoid a retention in the turbocharger,

  trailing a possible pumping of it. The control of these operations is provided by the control device 47 which, when passing from the lower range to the average load range, by the signals sent to its inputs 49 and 50,

  transmit via channel 48 a control signal to the

  tification 45 which, accordingly, and in a regular manner

  in accordance with the solid line 64 of FIG. 4, sets the director device 12 to the minimum passage section QLmin instead of the maximum section QLmax that it previously had, while passing from the middle range to the range higher charge, again from

  on a regular basis, he adjusts it to the maximum section. In return

  delaying the moment of injection and by regulating the

  supervisor at the maximum crossing section, which

  causes a decrease in the air pressure of over-

  In the engine cylinders, an ignition position can be obtained which, in the upper load range OLB, constantly keeps a value which is set at full load; this state is represented by the solid line 65 of FIG. 5. In addition, this measurement makes it possible to obtain in the upper load range OLB a combustion air ratio Av which constantly decreases by a maximum up to the value of fully loaded, and which is indicated in Figure 6 by the curve in full line 66. Following this reduction of the ratio of combustion air v

  - caused by the decrease of the air pressure of

  - it is also necessary to set a lower final compression pressure Pc in the upper load range. Fuel consumption

  results from the thermodynamic processes and conditions

  the operation, and in particular of the ratios between the ignition orse P and the effective pressure

  average P and P / pc * ratio.

  me wearing P Zpme rises in the upper load range

  OLB when applying the process according to the

  As a result of the more advantageous thermodynamic operating parameters, a lower fuel consumption is obtained, indicated in FIG. 7 by the solid line 67. In nominal load (100%), o PZ and

  Are fixed by construction, the process according to the invention

  This allows the fuel consumption to be lowered by adjusting the optimum ratio PZ / pc. Furthermore, it can be seen from the diagram of FIG. 7 that when the operating method according to the invention is applied, it is possible, approximately in a load range corresponding to 80% of the full load - therefore to the passage of the medium load range MLB to upper load range OLB - obtain the greatest decrease in fuel consumption, indicated by arrows, relative to a combustion engine

  internal combustion engine, including the exhaust turbocharger

  a directional device with an invariable section.

  However, this lower fuel consumption is manifested, when applying the operating method according to the invention, not only in the upper load range OLB, but, as indicated by the solid line 68 in FIG. 7, also in FIG. the average range of MLB charge. This last result is due to the fact that in this

  average MLB load range, the area of the listening section

  The steering device 12 is adjusted to the minimum flow, and thus, in spite of the smaller amount of exhaust gas supplied to the turbocharger, supercharger air at higher pressure can be supplied to the combustion chambers, which gives an ignition pressure P. which, as shown by the solid line 69 of FIG. 5, decreases with respect to the ignition pressure at full load but is still to a greater extent to a certain extent than the ignition pressure, represented by the

  42, which is established in the case of a

  rector set to maximum flow in this load range.

  Since thus, also in the medium MLB load range, the ignition pressure PZ is higher

  when the method according to the invention is applied, it is

  obligatory, in this region also, a more

  ratio of ignition pressure to actual pressure

  average (Pz / ss), which is the criterion of the least

  dre fuel consumption also in this range

charge.

  In the lowest load range -

  less than 10% - no significant progress can be made with regard to fuel consumption in relation to the known processes, since in this range, given the relatively small amount of exhaust gas and therefore the insufficient usable energy, the benefits of an exhaust turbocharger can hardly

to be smelled.

  It can be seen from the explanations above that, by applying the method according to the invention, the advantages of this one are obtained in particular in the medium and upper ranges of charge as well as in full load, ie from 15 to 100%. about charge. However, as these are generally known, the most frequent charge ranges in an internal combustion engine, the advantages of the method according to the invention, in particular the lower fuel consumption that one

  can get, are practically felt completely.

Claims (6)

R E V E N D I C A T I 0 N S   1.- Operating method of an engine   self-igniting internal combustion engine with a turbocharger   pressurized exhaust gas presser   dynamic arrangement, the steering device of which, connected in the gas turbine upstream of the turbine wheel in the direction of the exhaust gas, can be adjusted to vary the passage section, characterized in that the passage section (QL) of the device   director (12) so that (a) only in the lower range   of load (ULB) this section is brought to a maximum size (QLmax) (b) that in the medium load range (MLB) it is brought to a minimum magnitude (QLmin) and (c) that in the upper range of load (OLB), it is again brought to the maximum size (QLmax) and that, in addition, in this load range, the   moment of injection is simultaneously delayed relative   the average load range (MLB).   2. A process according to claim 1, characterized in that the passage of a passage section of the director device (12) to another is carried out from   on a regular basis to avoid restraint in the turbo-   exhaust gas compressor, resulting in pumping eventual of it.   3. A method according to claim 1 or 2, characterized in that the adjustment of the director device (12), passing from one load range to another, is automatically performed under the control of different   engine operating parameters.   4. A method according to claim 3, characterized in that the adjustment of the director device (12) is performed by a setting device (45) conjugate   with the latter, who receives the corresponding order   of a control device - (47) giving these control commands according to two operating parameters introduced in this device, namely the air pressure   and the position of the steering linkage -   armature (54) which adjusts the piston of an injection pump (56),   for determined quantities of these parameters.   5. A process according to claim 4, characterized in that the boost air pressure, msured by a pressure measuring device (51), is   converted into it into an electrical signal corresponding to   which is sent to the control device (47).   6. A method according to claim 4, characterized in that each position of the guide linkage (54) is reproduced by electrical signals generated according to the position and which are sent   to the control device (47) to be processed.