FR2752440A1 - COOLING SYSTEM FOR AN INTERNAL COMBUSTION ENGINE - Google Patents

Abstract

This system comprises an engine cooling circuit with a radiator, an external air duct leading to the engine and in which an exhaust gas turbocharger is arranged, as well as an exhaust gas recirculation duct containing a device. cooling. The cooling device (5) is integrated in the engine cooling circuit, to which it is connected by at least one branch line (7) and one return line (8). The exhaust gas recirculation pipe (15), after having passed through the cooling device (5) ends in the pipe (10) for supplying outside air leading to the engine (4). Applicable to diesel engines.

Description

The invention relates to a cooling system

  for an internal combustion engine, in particular for a diesel engine, with an engine cooling circuit, having an engine radiator, with an external air line leading to the internal combustion engine and in which a turbocharger is arranged. exhaust gas supercharger, as well as with an exhaust gas recirculation pipe in which

  is arranged a cooling device.

  DE-OS 25 41 156 discloses a method, as well as the devices necessary for its implementation, for supercharging a heat engine. according to

  this document, the recycled exhaust gases are introduced

  pressurized dusts in a part - also under pressure - of a compressor, more exactly at a location downstream of the rotor blade of the compressor. In a recycling line of the corresponding device of

  implemented, a cooling device is provided.

  is lying. It must be used to cool the gases

  before their introduction into the compres-

sor.

  However, with the method described in the document

  above mentioned, it is not possible to reduce the emission of pollutants, in particular the emission of NOx, or

  did not think of such a reduction.

  DE 32 20 832 C2 discloses a method for determining the exhaust gas recirculation rate of diesel engines, in which a target value of the exhaust gas recirculation rate is compared with an actual value of relating to the state of

  operation of the internal combustion engine. The temperature

  exhaust gas is detected as a

  the state of charge of this motor and used for the regulation of the exhaust gas recirculation rate during changes in the setpoint. A temperature measurement point to determine this state of charge

is also planned.

  This process is however very complicated and

  especially for a large number of parts or

  such as sensors and electrical circuits. It adds that it is not appropriate to reduce

the emission of NOx.

  The document DE 41 14 704 C1 describes a cooling system for a supercharged internal combustion engine, used for cooling in two stages the compressed supercharging air by an exhaust gas turbocharger. In this case, it has been provided that a cooling fluid required in a subsidiary branch is derived from a coolant stream leaving a high temperature return cooler and that the coolant

  passing through the internal combustion engine, flows

continued to this cooler.

  This cooling system, however, has the

  on the one hand, it has a very complicated structure

  and, on the other hand, that it does not contribute to

the emission of pollutants.

  According to the state of the art, the emission of NOx particles by diesel engines is still very high. The most diverse attempts at solution have been proposed to solve this problem. Thus, as a test, DENOx catalysts were equipped with diesel engines. However, given the reduction in NOx emissions, this solution is not sufficient

and furthermore relatively expensive.

  The invention therefore aims to reduce the emission

  of pollutants, in particular the NOx emission of an internal combustion engine, in particular a diesel engine.

  According to the invention, this result is achieved.

  This is because the cooling device is integrated in the engine cooling circuit, the cooling device being connected through to the engine cooling circuit.

  least one branch line and one line

  tower to the cooling system ducts of the

  the exhaust gas recirculation line, after having passed through the cooling device,

  opening into the outside supply air duct

  to the internal combustion engine.

  By the connection according to the invention of a

  positive cooling to the engine cooling circuit through a service line and a

  return, an integration of a dis-

  positive cooling in the cooling circuit

  the engine. Thus is created a cooling system

  to reduce the concentration of NOx and

  of particles. By providing for an adequate arrangement of the

  positive cooling, for example in the food

  hot water supply of the heating system, the waste heat of the exhaust gas (from the heat exchanger

  for the exhaust gas) can be used to heat

  the passenger compartment of the vehicle, which is

  all in the case of modern DE diesel engines which

  that a relatively small amount of heat ex-

cédentaire.

  An embodiment of the cooling system

  according to the invention provides that the bridging

  part of the fluid supply line

  refrigeration leading from the radiator of the vehicle (engine radiator) to the internal combustion engine, and that the

  return duct of the cooling device

  in the cooling fluid supply line.

  upstream of the internal combustion engine, with

  adjustment valves in the inlet pipe of the

  coolant and in the branch-pipe

  for the purpose of distributing the

froidissement.

  Another embodiment of the feedback system

  according to the invention provides that a circulation pump is installed in the service line

  which starts from the cooling fluid inlet pipe

  the radiator from the vehicle to the combustion engine

  internal control, and that the return conduct of the

  cooling system ends up in a

  engine cooling fluid tower leading to the

diateur of the vehicle.

  Other features and advantages of the

  will become clearer from the description

  which will follow several nonlimiting examples of embodiment, as well as the appended drawings, in which:

  FIG. 1 represents a cooling system

  dissement according to the invention according to a first embodiment, comprising solenoid valves; FIG. 2 represents a second mode of

  realization of a cooling system according to the in-

  vention, with an electric circulation pump; and - Figure 3 represents a third mode of

  realization of a cooling system according to the in-

  vention, with valves and an electric pump

of circulation.

  According to FIG. 1, a liquid stream of

  cooling, leaving a radiator 1 of the vehicle, is distributed in an adjustable manner, by solenoid valves 2 and 3, on an internal combustion engine 4 and a device

  5, representing a recycle cooler

  cling of exhaust gas. Valve 2 is in a

  coolant supply line 6 of the cir-

  engine cooling, driving to the internal combustion engine 4. Valve 3 is located in

  a branch line 7 leading to the

cold 5.

  Valves 2 and 3 are used to adjust the di-

  characteristic gram of the efficiency of the device of

  5. Through a return line 8

  5 of the cooling device 5, the cooling circuit of the engine 4 receives heat, which is particularly advantageous in the heating phase of the internal combustion engine 4. The latter receives external air through a valve set 9 exhaust gas recirculation. This valve is under the control of a

  characteristic diagram and its action depends on the com-

  Exhaust gas recirculation

  which has been taken into account in the design of the engine with

internal bustion 4.

  The outside air supply is effected in a known manner through an outside air supply pipe, in which a mass meter is installed.

  11, the compressor of a supercharger turbocharger

  exhaust system 12 and a cooler

Charge air 13.

  Due to cooling by cooling

  of the recycled exhaust gas 5, a larger quantity of charge gas can be supplied to the

  external air circuit of the internal combustion engine 4.

  This result is achieved by the fact that a recycling drive

  the exhaust gas valve 15 connects an exhaust pipe 14, at a point upstream of the turbine of the exhaust gas turbocharger 12, to the cooling device 5, and that the exhaust gas concerned, after having been suitably cooled in this device 5, are added in a mixture, through the exhaust gas recycling valve 9, in the

  external air supply duct 10. A regulator

  16 is provided in a known manner for the regulation of

turbocharger 12.

  The cooling circuit further contains a temperature measuring point 17 and a pressure measuring point 18, as well as a pipe 19 for measuring the temperature.

  return of the engine coolant.

  FIG. 2 represents a decoupled circuit for the cooling device 5, comprising a

  circulating electric pump 20 specific to this circuit.

  The cooling circuit of the motor 4 additionally contains the components shown in FIG. 1 and to which the same references have been given in FIG. 2. The valves 2 and 3 of the embodiment according to FIG. 1 are therefore replaced by the circulating pump 20 in the embodiment according to the

figure 2.

  If a thermostatic valve 21 being

  in the engine cooling circuit 4 is closed.

  this can be the case, for example, in the

  temperature, maximum cooling rates can be

  can be obtained by the electric circulation pump

  in the internal circuit thus formed.

  As the engine 4 does not release heat in this phase and as the engine cooling circuit is closed at this time vis-à-vis the return line 19 leading to the radiator 1 of the vehicle, the cooling circuit of the engine passes only via the connecting pipe 7 to the cooling device 5 and directly returns via the return pipe 8 to the inlet zone of the radiator 1. This circuit remains in service until the thermostatic valve 21 opens . The outside air circuit for the engine 4 and the exhaust gas recirculation are realized as

  described for the execution according to FIG.

  The purpose of the exemplary embodiment according to the

  gure 2 is to obtain a maximum cooling rate

  badly during the warm-up phase. After the opening of

  thermostatic valve 21, a mixed regime is pos-

  possible, but a regulation of the electric pump of cir-

  culation 20 is possible too. The chosen solution de-

hang from each application.

  Figure 3 shows an embodiment

  particular of the radiator 1 of the vehicle. Indeed, this

  diateur is divided into two parts la and lb. A stop valve 22 makes it possible to obtain, together with a reversal valve 23, a

  complete separation of the two circuits, namely the

  engine cooling and cooling circuit

  cooling of the cooling device.

  For optimization purposes, an appropriate combination is

  during possible too. The reason is that, thus, one can avoid the lowering of the temperature below

the fouling temperature.

  If the thermostatic valve 21 is closed, the engine cooling circuit extends from the radiator portion 1a through the stop valve 22 and the return line 8 of the cooling circuit of the cooling device 5 and consequently , until

  in the part lb of the radiator. In this mode of use

  the two parts 1a and 1b of the radiator are connected

  in series. After passing through the portion 1b of the radiator, the engine 4 receives, through a pipe 24 and the overturning valve 23, cooled water. In this way, a radiator 1 divided into two

  parts la and lb which can be combined in an appropriate manner

  quate according to the cooling needs. The

  tie lb of the radiator can be installed - especially under

  a chiller - at any location de-

  It is apparent from the foregoing that the cooling device 5 in this case has a cooling fluid circuit with a radiator or cooler 1b, for this fluid of the vehicle. cooling, which

are his own.

  In this embodiment also, the cooling air circuit and the exhaust gas circuit also correspond to the circuits shown on the drawing.

figure 1.

  It is also possible to install after cooling a cooling system according to the invention since the design of the radiator of the vehicle does not require to be modified for the implementation of the invention. Indeed, the recycling of exhaust gases is not provided for in

  operating point on which the design is based

  radiator, that is to say on the full

  charge at low speed. Instead, the cooling

  of recycled exhaust gases between only

  action in a partial load range, more exact-

  for example, in a range between

  idle speed and rotational speeds used at approximately 3/4 of the nominal power, ie at engine loads between the zero load and 75% of the

maximum charge.

Claims (7)

  1. Cooling system for an internal combustion engine, in particular for a diesel engine, with an engine cooling circuit, having an engine radiator, with an external air duct leading to the internal combustion engine and in which is arranged an exhaust gas turbocharger, as well as with an exhaust gas recirculation pipe in which a cooling device is arranged, characterized in that the device   cooling circuit (5) is integrated in the recirculation circuit.   engine cooling, cooling device   (5) being connected through at least one branch line   (7) and a return line (8) to the engine cooling system lines (6, 19), and the exhaust gas recirculation line (15), after   have passed through the cooling device (5), de-   plugging in the outside air supply line (10)   leading to the internal combustion engine (4).   2. Cooling system according to the   cation 1, characterized in that the conduct of branch-   (7) part of the fluid supply line   cooling (6) leading from the radiator (1) of the vehicle to the internal combustion engine (4)   and that the return line (8) of the cooling device   (5) ends up in the arrival line of   coolant (6) upstream of the combustion engine   internal bustion (4), with provision of control valves   (2, 3) in the cooling fluid inlet pipe   (6) and in the service line (7) in order to   a distribution of the cooling fluid stream is lying.   3. Cooling system according to the   cation 1, characterized in that a circulation pump (20) is installed in the connecting pipe (7) which starts from the cooling fluid inlet pipe (6) leading from the radiator (1) of the vehicle to the engine internal combustion engine (4), and that the return line (8) of the cooling device (5) terminates in a motor coolant return line (19) leading to the radiator (1) of the vehicle.   4. Cooling system according to the   cation 1, characterized in that the cooling device   (5) has a cooling fluid circuit.   with a radiator (lb), for the fluid of   cooling, which are its own.   5. Cooling system according to the   cation 4, characterized in that the radiator (1b) can be connected in series with the radiator (1) of the vehicle.   6. Cooling system according to the   cation 4 or 5, characterized in that the radia-   (lb) is flanged on the radiator (1) of the vehicle. cule.   7. Cooling system according to the   cation 1, characterized in that the lost heat of the heat exchanger for the exhaust gas is   used to heat the cabin of the vehicle.