Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
  • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
  • F02M26/22—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories with coolers in the recirculation passage
  • F02M26/23—Layout, e.g. schematics
  • F02M26/28—Layout, e.g. schematics with liquid-cooled heat exchangers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
  • F01P5/00—Pumping cooling-air or liquid coolants
  • F01P5/10—Pumping liquid coolant; Arrangements of coolant pumps
  • F01P2005/105—Using two or more pumps
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
  • F01P2060/00—Cooling circuits using auxiliaries
  • F01P2060/08—Cabin heater

Definitions

• the invention relates to a device for the thermal regulation of recirculated gases of an internal combustion engine.
• a heat exchange is generally provided between these gases.
• recirculated exhaust and engine coolant a recircled gas / heat transfer liquid heat exchanger is supplied with coolant at the engine outlet by a stitching on the engine water outlet housing, upstream of the thermostat.
• FIG. 1 illustrates a device for the thermal regulation of the recirculated gases of an internal combustion engine according to the prior art, comprising a heat transfer liquid circuit 1 connected to an internal combustion engine 2, the circuit comprising first means 3 of heat exchanger coolant / air A, such as a radiator, located in a first loop 13 connected to the engine 2, second recirculating liquid heat exchange / recirculating exhaust gas exchange means GB 4 located in a second loop 14 connected in parallel to the first loop 13, to allow the supply of the second 4 exchange means heat transfer liquid from the first 3 heat exchange means.
• first means 3 of heat exchanger coolant / air A such as a radiator
• the flow of coolant admitted to circulate in the first loop 13 is controlled, for example, by a thermostat 7 located in the housing 16 of water outlet.
• a first pump 10, for example mechanical, linked to the engine 2 ensures the activation of the fluid flow in the cooling circuit 1.
• the second exchanger 4 liquid / recirculated gas exchanger
• a conventional radiator creates a pressure drop of the order of 300 mbar.
• a standard electric pump 5 provides in the second loop 14 a back pressure of about 200 mbar, therefore less than the pressure drop in the radiator 3.
• this parasitic flow direction is represented by the arrows 24 in FIG. 1).
• This reversal of circulation is preceded by an operating point during which there is a zero or almost zero flow in the second exchanger 4. This operating point at zero flow can occur, for example at a speed of the order of 2700 rpm.
• one solution is to have a non-return valve 17 in the second branch 14, so as to reduce the flow rate therein in the engine cooling phase (see Figure 1).
• This solution is generally satisfactory for the reverse parasite flow but it entails a significant additional cost in the context of a large scale production.
• the use of a non-return valve generates an additional pressure drop in the hydraulic circuit and requires calibrating a leak to maintain a minimum flow in the exchanger 4.
• Another solution is to increase the power of the electric pump disposed in the second loop 14.
• An object of the present invention is to overcome all or part of the disadvantages of the prior art noted above.
• the device for regulating the heat of the gases reci ructed from an internal combustion engine is essentially characterized in that that the ends of the second loop are connected directly to the body of the first heat exchange means.
• the invention may include one or more of the following features:
• the ends of the second loop are respectively connected to inputs and outputs of the first heat exchange means, which are distributed between the input and the output of the connection of the first heat exchange means to the motor,
• the ends of the second loop are connected to the first heat exchange means so as to connect the input and output of the second heat exchange means with, respectively, the outputs and the input of the first heat exchange means,
• the first heat exchange means comprise at least one heat exchanger beam connected to a fluid inlet housing and a fluid outlet housing, the ends of the second loop being connected directly to the respective fluid inlet and outlet boxes,
• the second loop comprises activation means controlled by the flow of heat transfer fluid, such as a pump, the device comprises means for regulating the flow rate of heat transfer fluid allowed to circulate in the first loop,
• the flow control means comprise a proportional type valve, such as a thermostat,
• the flow control means comprise a pump
• the means for activating the flow rate in the second loop and the means for regulating the flow rate in the first loop are independent, so as to enable the flow activation means to start or stop in the second loop, regardless of the flow of coolant admitted to circulate in the first loop.
• FIG. 1 represents a schematic view of a cooling circuit of an internal combustion engine according to the prior art
• FIG. 2 represents a schematic view of a cooling circuit of an internal combustion engine according to an exemplary embodiment of the invention
• FIG. 3 represents a diagrammatic front view of a detail of FIG. 2, illustrating an exemplary embodiment of the heat exchange means such as a radiator according to the invention
• FIG. 4 represents a cross-sectional and schematic cross-sectional view of the heat exchange means of FIG. 3, along the line AA,
• FIG. 5 schematically represents a graph illustrating comparative fluid flow rates of cooling in the second loop 14 of the circuit according to the engine speed.
• the thermal control device also comprises a third loop 19, optional connected in parallel with the first 13 and second 14 loops of the circuit 1.
• the third loop 19 comprises a coolant / air exchanger 18 such as a heater for, for example, giving calories to a volume such as a vehicle cabin.
• Such an internal combustion engine 2 conventionally comprises intake ducts (not shown) delivering fresh gases into the cylinders of the engine 2.
• the GB burnt gases from the combustion in the cylinders are collected by exhaust ducts (not shown).
• a bypass makes it possible to recirculate a fraction of the exhaust gases at the intake level.
• the bypass may comprise for this purpose a controlled valve for regulating the flow rate of the recirculated exhaust gas.
• the circuit 1 according to the invention differs from that described above in that the second loop 14 which contains the exchanger 4 heat transfer liquid / recirculated exhaust gas GB is connected in parallel to the first loop 13 directly on the body of the first means 3 of heat exchange. Furthermore, this second loop 14 may dispense with non-return valve 17 and in this case contains only a pump 5, preferably electric.
• the two ends of the second loop 14 are connected directly to the radiator 3, so as to connect the inlet 11 and outlet 12 of the exchanger 4 heat transfer liquid / recirculated exhaust gas with respectively 6 and input 5 of the radiator 3.
• the radiator 3 may comprise a heat exchanger comprising at least one bundle 7 of tubes / fins whose ends are respectively connected to a fluid inlet housing 8 and a fluid outlet housing 9 (FIGS. 3 and 4).
• the two ends of the lines of the second loop 14 can be connected directly to, respectively, the inlet casings 8 and the fluid outlet 9 of the radiator 3.
• the invention thus makes it possible to minimize the hydraulic head losses at the terminals of the circuit 14, in particular within the fluid outlet inlet casings 9, with respect to the system according to the prior art in which the second loop 14 is connected. on pipes or hoses of the first loop.
• the invention thus makes it possible, for the same type of pump 5 arranged in the second loop 14, to push the operating points at risk to higher speeds.
• FIG. 5 illustrates on a same graph the variation of the flow rate D of cooling fluid in the exchanger 4 coolant / exhaust gas recirculated in liters per minute (in ordinate) as a function of the engine speed N in revolutions per minute ( on the abscissa).
• the graph represents this flow rate for a circuit according to the prior art (curve 20) and for a modified circuit according to the invention (curve 21). That is to say that for a hydraulic circuit according to the prior art (according to FIG. 1), it can be seen that the flow rate in the second loop 14 and therefore in the exchanger 4 liquid / recirculated gas becomes zero and reverses from 2700 rpm. about.
• the invention allows a thermal regulation
• the ends of the second loop 14 can be connected respectively to input 5 and output 6 of the radiator 3 which are distinct from the input 15 and output 16 connecting the radiator 3 to the engine 2.
• the device according to the invention makes it possible, with a simple and inexpensive structure, to guarantee an optimum temperature for the recirculated exhaust gases.
• the nominal efficiency of the recirculated liquid / exhaust gas exchanger 4 is maintained over a very wide engine operating range (and encompassing the currently defined use points of this exchanger).
• the invention makes it possible to ensure a minimum flow rate of 5 to 6 l / min in a conventional exchanger 4 when the latter must be operational.
• the circulations of the coolant in the first 13 and second 14 loops can be controlled independently.
• the circulation of the coolant in the third loop 19 is also independent of the circulation in the other loop 14.
• the circuit 1 makes it possible to feed the exchanger 4 coolant / recirculated exhaust gas with liquid cooled by the radiator 3.
• the heat transfer fluid circulating in the exchanger 4 coolant / recirculated gas remains at a temperature close to room temperature. In this way, the efficiency of the exchanger 4 is improved, which promotes the reduction of pollutants in the engine exhaust gases (especially NOx).
• the electric pump 5 of the second circuit 4 can be started to increase the heat exchange between the coolant and the recirculated exhaust gas.
• Stopping this electric pump 5 also makes it possible to eliminate the circulation of coolant in the exchanger 4 liquid / recirculated gas in the engine start phase, that is to say at a time when the starting of a catalysis system is not yet initiated (usually when the temperature of the exhaust gas is below a threshold temperature of between 100 and 250 0 C, generally about 150 0 C).
• This configuration makes it possible to reduce the pollutants of the type in particular CO and HC and thus makes it possible to eliminate the conventional by-pass on the coolant or on the exhaust gases.
• Means for measuring the temperature of the exhaust gas such as a probe may be provided for this purpose at the exhaust.
• the circuit 14 includes a check valve, when the recirculation of the exhaust gas is interrupted by the corresponding valve, the pump 5 located in the second loop 14 is not turned on.
• the pump 5 is stopped with a determined time after this stop recycling.
• the pump 5 located in the second loop 14 is energized only when the exhaust gas is recirculated and the temperature of the latter has reached a threshold value (catalyst initiated).
• the thermostat 7 When the operating configuration of the engine requires simultaneous cooling of the engine 2 and recirculated exhaust gas, the thermostat 7 is open and the pump 5 located in the second loop 14 is turned on.
• the coolant cool in the radiator 3 is shared between the engine 2 and the exchanger 4 liquid / recirculated gas.
• the radiator 3 is fed with a mixture of liquid from the engine 2 and the recirculated liquid / exhaust gas exchanger.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Exhaust-Gas Circulating Devices (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2005
  • 2005-02-14 FR FR0550416A patent/FR2882105B1/fr not_active Expired - Fee Related
• 2006
  • 2006-02-07 JP JP2007554611A patent/JP2008530429A/ja active Pending
  • 2006-02-07 WO PCT/FR2006/050105 patent/WO2006085024A1/fr active Application Filing
  • 2006-02-07 EP EP06709484A patent/EP1848887A1/fr not_active Withdrawn
  • 2006-02-07 US US11/816,223 patent/US20080257526A1/en not_active Abandoned

Non-Patent Citations (1)

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