FR2639403A1 - INTERNAL COMBUSTION ENGINE WITH MULTIPLE CYLINDERS - Google Patents

Abstract

In this engine, in particular for a motor vehicle, an additional exhaust valve 26 provided for each cylinder controls a throttling pipe 23 interposed between the cylinder chamber 20 and an exhaust pipe so that, in the engine braking mode of the engine , air is expelled from the cylinder chamber into the exhaust duct, developing a throttle work. To prevent air transfer from cylinder to cylinder, each throttle line has a check valve 38 which opens to the exhaust duct and keeps the throttle line closed when the pressure is higher. in the exhaust duct than in the cylinder chamber.

Description

Internal combustion engine with several cylinders.

  The invention relates to a combustion engine

  internal combustion with several cylinders, in particular one

  for propelling a motor vehicle and which comprises distribution channels and, for each cylinder, on the one hand, an exhaust valve

  which controls a throttling line between

  between the cylinder chamber and an engine exhaust gas duct such that air flows from the cylinder chamber into the engine exhaust duct.

  exhaust gas in the engine brake mode, developing

  pant then a work of throttling or rolling and,

  on the other hand, a non-return valve, mounted in the con-

  the throttle duct opening towards the exhaust duct, and intended to keep the throttling duct closed when the pressure of the exhaust duct is greater than that of the chamber

of the cylinder.

  An internal combustion engine of this type is

  known from DE-34 28 626 A1. In this combustion engine

  tion already known, the additional scalding

  the engine brake mode, so that during the suction time, air can be drawn from the exhaust duct into the chamber of the cylinder considered through the valve. additional open exhaust, especially when there is a higher pressure in this duct, which occurs while a compression or expansion time is taking place in a cylinder

  neighbour. This transfer of cylinder air to cylinder cylinder

  the total flow of air discharged by the engine into the

  motor brake mode. It is then necessary to develop temporary

  unacceptably high levels of air, which may

  to pass the exhaust gas temperatures of the

engine.

  The invention is intended to avoid the trans-

  cylinder air from cylinder to cylinder

  additional exhaust valve in a combustion engine

  internally defined type at the beginning in the engine brake mode. In an internal combustion engine of the kind in question, this problem is solved by the fact that when this engine is provided with distribution valves which command the distribution ducts (intake duct, exhaust manifold) the valve of additional exhaust is constituted by a

  check valve which is kept closed by a

  lock in the engine mode of the

  internal combustion and whose locking effect is

Drunk in the engine brake mode.

  In the internal combustion engine realized se-

  According to the invention, the non-return valve is opened in the engine brake mode, during the compression and expansion time of the cylinder considered as long as the

  The pressure in the cylinder chamber is greater than that

  the exhaust pipe, so that compressed air can flow into the exhaust pipe, through the exhaust valve

  additional, by developing a rolling work.

  As soon as the exhaust valve opens and there is a balance of pressures between the cylinder chamber and the exhaust pipe, the check valve closes, so that in the time of suction that follows, the suction of the air coming from the

  exhaust through the throttle

  and, therefore, the transfer of cylinder air

  to cylinder, are deleted. The non-return valve is thus controlled by the pressure differences that are established between the cylinder chamber and the duct

  of gas in the unfolding of different times.

  According to a simple embodiment to manufacture

  which has a clear and functional separation

  between the additional exhaust valve

  and the check valve, the additional escape valve

  is permanently open in the engine brake mode and the non-return valve is inserted in the

  throttling line downstream of the exhaust valve

additionally.

  According to another embodiment, in the-

  which only the locking device must

  be operated from the outside while the

  additional exhaust, constituted by a non-return valve, opens and closes automatically at the rhythm of the operation of the engine, and in which the

  throttling line may be of a particular conformation

  particularly short, the exhaust valve

  It consists of a non-return valve which is

  kept closed in the engine mode of the engine by a

  Locking device whose locking is removed

m in the engine brake mode.

  In a practical embodiment of the

  internal combustion engine which has this characteristic

  the locking device is constituted by a spring-loaded control piston, which can be retracted into the engine brake mode under the effect of the biasing of a fluid under pressure and against the force of the spring, and which has a ramp that

  maintains the check valve in the closed state by

  against this valve in the engine mode, while in the engine brake mode when the control piston

  is retracted, this ramp releases the valve.

  According to one embodiment of the invention,

  the throttling line shows a decreasing

  gradual section from the cylinder chamber to its junction with the exhaust gas duct, passing by the additional exhaust valve and

oar the check valve.

  In this embodiment, where there is a constant increase in air velocity in the throttle line, the passage section which is the main determining factor for the throttling effect is constituted by the section of the throttle. outlet of the throttle line in the exhaust duct, which must be calculated with Accuracy

  in the practical embodiment.

  According to another characteristic of the invention, it provides, as a motor brake, a brake louver arranged in the exhaust gas duct or in the exhaust gas duct which connects to it and which narrows the section in the engine brake mode. In this case, the measurements made according to the invention have a particularly favorable influence on the rolling effect and, consequently, on the braking power of the air pumped into the cylinders since, thanks to the suppression of the transfer of the air cylinder cylinder, the air discharged in the engine brake mode is forced to completely traverse the rolling slot formed between the brake damper and the gas duct

  exhaust or the exhaust gas collecting duct

  by developing a rolling work.

  In the following, the invention will be exposed

  in more detail about several examples of

  shown in the drawings. On these drawings,

  FIG. 1 schematically represents a

  known multi-cylinder internal combustion engine,

  additional exhaust valves which

  provide throttling lines and an exhaust flap interposed in an exhaust manifold pipe; FIG. 2 is a partial view of an internal combustion engine comprising a throttle duct controlled by a

  additional exhaust valve and by means of an

  ti-back; FIG. 3 is a partial section of an internal combustion engine similar to that of FIG. 2,

  including an additional exhaust valve

  staggered by a non-return valve; and

  Figure 4 shows schematically the evolution

  section of a throttling line.

  The four-stroke internal combustion engine 1

  of Figure 1, which is already known, comprises three cylinders

  2, 3, 4, to each of which are associated an intake duct 5, 6, 7, equipped with an intake valve 8, 9, 10, and an exhaust gas duct 11, 12, 13

  equipped with an exhaust valve 14, 15, 16, the

  exhaust fumes uniting to form an exhaust manifold 17. In this

  conduct is arranged a brake louver 18 which, in the

  brake, takes the closed position reorésen-

  which leaves free a throttling slot or

  19. The cylinder chamber 20, 21, 22 of each

  that cylinder 2, 3, 4 is further connected to the corresponding exhaust gas duct 11, 12, 13 via a throttle line 23, 24, 25 which is controlled by

  an additional exhaust valve 26, 27, 28.

  In the engine brake mode of the internal combustion engine

  1, these valves constantly take the entire position

  open which is represented. The cylinder of

  ch 2 is in the compression time, the cylinder

  central dre 3 in the relaxation time, and the right cylinder 4 in the time of asante. In this way, there prevails in the exhaust pipes 11, 12, and consequently in the exhaust gas collecting pipe 17 and in the exhaust pipe 13, a pressure greater than that prevailing in the

  cylinder chamber 22, so that the air that is expelled

  Cylinder chambers 20, 21 flow into the chamber.

  22 of the cylinder 22 passing the additional exhaust valve 28 which is open. Cylinder-to-cylinder air transfer raises air temperature to unacceptable levels; on the other hand, a smaller amount of air escapes through the throttle slot 19 formed by the brake louver 18, so that the throttling and braking power of

this slot décottott.

  As has been shown in more detail

  2, the throttle line 23 (24, 25) is closed by applying the valve head 29 of the additional exhaust valve 26 (27, 28) to the seat 30, and a The chamber 31 is provided upstream of the seat 30, on the side of the cylinder chamber 20, (21, 22), to receive the valve head 29 when the additional expansion valve 26 is open. At the end of the stem 32 of the valve

  exhaust system 26 which is the furthest

  the head of the valve, there is a plate of

  34 pressure sliding in the block 33 of the engine to com-

  internal combustion 1 and which limits, on its rear face, a pressure chamber 35 which is supplied with pressure fluid, for example compressed air or oil

  under pressure through a pressure line

  36 in the motor brake mode of the engine, so that the additional exhaust valve 26 is then

  open against the force of a jurisdiction 37 and

  then binds the chamber 20 of the cylinder to the throttling line. When the pressure is removed in

  the pressure chamber 35, at the end of the modulating brake mode

  the spring 37 returns the additional exhaust valve

  26 at its closing position.

  The throttling line 23 contains in

  between the valve seat 30 and the exhaust gas duct 11, a non-return valve 38 which closes the throttle line 23 when its head 39 is apolic

on a valve seat 40.

  The non-return valve 38 takes the position

  when the additional exhaust valve

  tional 26 is open, the force that is exerted on the head of claoet 39 by the pressure difference between

  the cylinder chamber 20 and the exhaust gas duct

  11 is greater than the force of a spring 41 which acts in the closing direction while in all

  other cases, that is to say in particular when

  In the exhaust duct 11, a higher pressure than in the cylinder chamber 20, the nonreturn valve 38 is closed, so that the air reflux to the cylinder chamber 20, and consequently

  air transfer from cylinder to cylinder, are removed

with certainty.

  In the embodiment of FIG.

  the additional exhaust valve 26 constitutes

  the same non-return valve 38 which is essentially composed of a valve part 42 and a pressure part

  43, between which is compressed a compressor spring

  44. The valve part 42, which slides

  45 block 33, close the throttle line 23

  by applying to a valve seat 46 and thereby separating

  if this conduct of the cylinder chamber 20. To

  that the valve portion 42 will remain permanently in the closed position in the engine mode of the internal combustion engine, this valve head is strongly applied to the valve seat 46 by a control piston 47 belonging to a locking device

  38, via a pressure portion 43.

  For this, the control piston 47, which is loaded oar a compression spring 49, and which slides in a bore 50 perpendicular to the bore 45, presents a ramoe 51 which is pressed by the compression spring S 49 against a roller 52 Dorté by the pressure portion 43, which in turn holds the valve portion 42 applied to the valve seat 46 via

  53. In the engine brake mode of the combustion engine

  internal bombardment, a pressurized fluid is introduced into a dredging chamber 54 formed in the bore, through the pressure line 36, so that the control piston 47 is pushed back against

  of the force of the compression spring 49 through the

  pressure piston 55. In this way, the

  pressure portion 43 may fade upwards,

  as the valve portion 42 remains held down on the valve seat 46 by a compression spring 44 as long as the force exerted on the valve portion 42 by the pressure of the cylinder chamber is

  less than the force of the pressure spring 44.% eci ex-

  also in this embodiment the suction

  air to the cylinder chamber 20 through the con-

throttling speed 23.

  In Figure 4, it has been shown that the section of

  passage of expelled air through the conduct of foreign

  23 (24, 25) continually decreases between

  lindre 2 (3, 4) and the exhaust duct 11

  (12, 13) and that the flow velocity increases accordingly.

  accordingly. The reduction of section is done here in steps

  by the bore of the cylinder and the sections of the

  pre-chamber 31 (F1) of the additional exhaust valve

  26 (F2), of the non-return valve 38 (F3), to reach the section of the outlet (F4) in the exhaust pipe 11, which is calculated in such a way as to

  get throttling and braking power as well

  as good as possible without, thanks to the evolution profile

  section, the amount of air ex-

  oulsé be excessively reduced, which would reduce the

throttling power.

R E V E N 0 I C AT IO N S

  1. Internal combustion engine with several cylinders

  dres, in particular an engine intended for propulsion

  of a motor vehicle which includes

  tribution and, for each cylinder, on the one hand, a

  additional escape valve which controls a driving

  the throttle interposed between the cylinder chamber

  dre and exhaust pipe of the engine of such

  the way air flows from the cylinder chamber

  dre in the exhaust duct in the mode

  engine brake, then developing a strangling

  or rolling and, on the other hand, a check valve

  tower, mounted in the throttle pipe when opening

  to the exhaust duct and intended for

  the closed throttle line when the pressure

  of the exhaust gas duct is greater than that of the cylinder chamber, characterized in that, in an internal combustion engine (1) provided with distribution valves (intake valve 8, 9, 10, 11, 12, 13) - which control the distribution ducts (intake duct 5, 6, 7, duct

  11, 12, 13), the additional exhaust valve

  (26, 27, 28) consists of an annular flap

  return (38) which is kept closed in the

  of the internal combustion engine by means of a

  latch (48), the locking effect of which is

Drunk in the engine brake mode.

  2. Internal combustion engine according to claim

  cation 1, characterized by the fact that the locking device

  ge (48) is constituted by a spring-loaded control piston (47) which can be retracted in the

  motor brake under the effect of the solicitation of a

  under pressure and against the force of the spring, and which has a ramp (51) which maintains the non-return valve (38) in the closed state by pressing against this valve in the engine mode, while that in the mode

  when the control piston is retracted

this ramp releases the valve.

  3. Internal combustion engine according to a

  conque of claims 1 and 2, characterized in that

  the throttling line (23, 24, 25) has a di-

  gradual reduction of section from the cylinder chamber

  dre (20, 21, 22) to its junction with the conduit of

  exhaust gas (11, 12, 13), via the

  additional exhaust (26, 27, 28) and the

check valve (38).

  4. Internal combustion engine according to a

  one of claims 1 to 3, characterized in that

  brake flap (18) is arranged in the gas conduit

  (11, 12, 13) or in the collector line.

  exhaust gas (17) connected thereto for

  vir brake motor, this shutter narrowing section

in the engine brake mode.