Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
  • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
  • F02D13/0203—Variable control of intake and exhaust valves
  • F02D13/0207—Variable control of intake and exhaust valves changing valve lift or valve lift and timing
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
  • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
  • F02D13/0273—Multiple actuations of a valve within an engine cycle
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
  • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
  • F02D13/0261—Controlling the valve overlap
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/10—Internal combustion engine [ICE] based vehicles
  • Y02T10/12—Improving ICE efficiencies

Definitions

• the invention relates to vehicle engines.
• internal combustion engines of vehicles it is conventional to implement recirculation of exhaust gas or EGR. This is the case, for example, in compression-ignition diesel engines for which, at certain operating points, recirculation of the unburned gases is carried out.
• EGR gases in larger or smaller quantities in diesel engines significantly reduces the nitrogen oxides, or NOx, emitted into the atmosphere.
• the temperature of the recirculated exhaust gas also has a strong influence on pollutant emissions, especially on unburnt low engine loads.
• the aim is to reduce unburnt emissions at low loads.
• diesel engines are increasingly using an EGR gas cooling system to limit NOx emissions.
• this cooling has the effect of increasing the emissions of unburnt at low engine loads when the engine is cold and the oxidation catalyst is not primed.
• An object of the invention is to further improve the performance of engines with respect to anti-pollution standards.
• a control method of a vehicle engine in which an opening movement is given to at least one intake valve while an opening movement is given to at least one an exhaust valve associated with the same cylinder as the intake valve.
• the method according to the invention may also have at least one of the following characteristics:
• the opening movement of the exhaust valve is started after starting the opening movement of the intake valve; the two opening movements have different amplitudes;
• a closing movement is given to the intake valve while a closing movement is given to the exhaust valve.
• Also provided according to the invention is a method of controlling a vehicle engine, in which a closing movement is given to at least one intake valve while a closing movement is given to at least one valve of exhaust associated with the same cylinder as the intake valve.
• the method according to the invention may furthermore have at least one of the following features: - the closing movement of the intake valve is completed before completing the closing movement of the exhaust valve;
• the exhaust valve is kept closed and during this time it opens and then closes the inlet valve; during a cycle of the engine, the intake valve is opened twice and the exhaust valve only once;
• the two openings of the intake valve have different amplitudes
• the inlet valve is kept closed and during this time the exhaust valve is opened and then closed;
• the exhaust valve is opened twice and the intake valve only once;
• the two openings of the exhaust valve have different amplitudes; it is implemented only when a motor load is lower than a predetermined value;
• the engine is a diesel engine with direct injection.
• a vehicle engine comprising: at least one cylinder;
• a vehicle engine comprising:
• FIG. 2 shows valve lift curves illustrating two examples of implementation of the method of the invention
• FIG. 3 is a diagram illustrating comparative test results between a motor of the prior art and the two examples of implementation of FIG. 2 and illustrating on the columns and on the y-axis on the left the emission of hydrocarbons. and on the curve and in ordinate on the right the consumption of fuel; and
• FIG. 4 is a diagram similar to FIG. 3 illustrating the hydrocarbon emissions and the exhaust temperature.
• FIG. 1 schematically illustrates a motor 2 according to a preferred embodiment of the invention.
• This engine comprises an air filter 4 communicating with a compressor 6 of a turbocharger 8.
• a line 10 indirectly communicates the compressor with an intake manifold 12 controlling the admission of gas into cylinders 15 formed in a cylinder head 14 of the motor.
• each cylinder is a piston not shown.
• each cylinder is associated with at least one intake valve and at least one exhaust valve, and preferably two of each. The movement of the exhaust valves is controlled by an exhaust manifold 16.
• the engine comprises an external exhaust gas recirculation circuit 18 taking a fraction of the exhaust gas at the outlet of the cylinder head for reinjecting them into the circuit
• the amount of exhaust gas recirculated by this circuit 18 can be controlled by means of a valve 20 in a manner known per se.
• the circuit 18 includes in particular a cooler and a bypass of the latter which have not been illustrated.
• the fraction of the non-recirculated exhaust gas rotates a turbine 22 of the turbocharger 8 and is conveyed to an exhaust device 24 comprising in particular an oxidation catalyst 26.
• the external EGR circuit 18 which feeds the intake circuit with highly cooled burnt gases. Indeed, at these operating points, it is mainly the NOx emissions that must be reduced.
• the unburnt emissions are relatively low and the oxidation catalyst is already primed.
• valve lift laws are modified through the distributors 12 and 16.
• the first embodiment is that of the configuration 1. Briefly, in addition to performing the normal engine cycle at the valves, opening the intake valves while opening the exhaust valves for the exhaust.
• the diagrams of Figure 2 shows on the abscissa the rotation angles of the engine crankshaft and the ordinate the extension of each valve out of its housing. More precisely, in the configuration 1, at the same time that the opening movement of the exhaust valves for the evacuation of the gases present in the cylinder (curve 2) is started, an opening movement of the valves of the cylinder is started. admission (curve 1). The two opening movements, however, have different amplitudes so that the amplitude of movement of the intake valves is less than the amplitude of the movement of the exhaust valves. Knowing that all the valves are moving at the same speed, and that the closing movement of each of these valves begins once it has reached the intended open position, it follows that the closing movement of the valves begins.
• each intake valve and once each exhaust valve are opened twice.
• the two successive openings of each intake valve have different amplitudes from each other, the amplitude being less in the exhaust than during the admission.
• the cycle is as follows. Firstly, the closed intake valves (curve 1) are maintained while the exhaust valves (curve 2) are opened and closed in order to exhaust in a conventional manner.
• the exhaust is closed by closing when the piston reaches top dead center.
• the opening movement of the intake valves is started and then, after a period corresponding, for example, to approximately 60 ° of crankshaft angle, an opening movement of the exhaust valves is started. Consequently, during a certain period, the opening movements of the exhaust and intake valves are simultaneously performed.
• the intake valves have reached the end of their path before this is the case for the exhaust valves.
• the closing movement of the intake valves begins while the opening movement of the exhaust valves is not yet complete.
• each exhaust valve and once each intake valve are opened twice.
• the two successive openings of each valve exhaust have different amplitudes from one another, the amplitude being less during the intake than during the exhaust.
• Distributors 12 and 16 for implementing these control laws can be easily made from distributors of the prior art.
• the opening of the two intake valves during the exhaust phase allows a portion of the burned gases to be stored in the intake plenum before being reintroduced into the cylinders during admission. next.
• This short loop of the EGR gases makes it possible to introduce hot gases that are hotter than in the case of a conventional circuit.
• Configuration 2 allows a greater reduction in unburnt emissions and an increase in exhaust temperature. Although it seems more interesting, the configuration 1 is also interesting.
• This invention can be implemented on all engines, regardless of the number of valves per cylinder (one or two exhaust valves, one or two intake valves) and whatever the motive of the valves, that it 0 ° or 90 ° valve action. It is observed that, in configuration 1, the intake valves being open during the exhaust phase, a portion of the burnt gases is stored in the intake plenum before being reintroduced into the cylinder during admission. next. This short loop of the EGR gases makes it possible to introduce hot gases that are hotter than in the case of a conventional circuit.
• the hot flue gases are introduced together with the fresh air. Therefore, the flue gases are very hot.
• Both strategies have many advantages. They are particularly adapted to the diesel engine.
• the simultaneous opening of the exhaust and intake valves makes it possible to greatly increase the amount of internal EGR without causing an impact between the valves and the piston. In addition, there is no overconsumption of fuel.
• the simultaneous opening of the exhaust and intake valves does not affect the negative loop of the PMI.
• the invention makes it possible to increase the amount of internal EGR gas without increasing the fuel consumption on the lightly loaded operating points of the engine or when the engine is cold. On moderately and heavily loaded operating points, it is the external EGR circuit that supplies the engine with highly cooled flue gases. Indeed, on these operating points, it is mainly the NOx emissions that it is necessary to reduce, the emissions of unburnt being lower and the oxidation catalyst being initiated.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Output Control And Ontrol Of Special Type Engine (AREA)
• Valve Device For Special Equipments (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=34950184

Family Applications (1)

Country Status (5)

Families Citing this family (5)

Family Cites Families (18)

• 2004
  • 2004-10-25 FR FR0411342A patent/FR2877047A1/fr active Pending
• 2005
  • 2005-10-25 JP JP2007537359A patent/JP2008518144A/ja active Pending
  • 2005-10-25 US US11/577,959 patent/US20080121210A1/en not_active Abandoned
  • 2005-10-25 WO PCT/FR2005/050897 patent/WO2006045982A2/fr active Application Filing
  • 2005-10-25 EP EP05816047A patent/EP1807617A2/de not_active Withdrawn

Non-Patent Citations (1)

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