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
  • F02D13/0223—Variable control of the intake valves only
  • F02D13/0226—Variable control of the intake valves only changing valve lift or valve lift and timing
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/26—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder
• • 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
  • F02D13/0223—Variable control of the intake valves only
  • F02D13/0234—Variable control of the intake valves only changing the valve timing only
• • 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
  • F02D13/0257—Independent control of two or more intake or exhaust valves respectively, i.e. one of two intake valves remains closed or is opened partially while the other is fully opened
• • 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
  • F02D13/0269—Controlling the valves to perform a Miller-Atkinson cycle
• • 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 a combustion engine.
• the invention relates more particularly to a four-stroke internal combustion engine, of the type comprising an air / fuel mixture intake circuit and a circuit for exhausting burnt gases which communicate with a combustion chamber of at least a cylinder of the engine, of the type in which the communications of the intake and exhaust circuits with the chamber are capable of being each closed by at least one valve with controlled opening, respectively of intake and exhaust , and of the type in which a turbocharger makes it possible to increase the pressure for admitting the mixture into the chamber.
• a turbocharger to increase the performance of a thermal engine with a given displacement is known and has many advantages.
• the actual compression ratio of the fuel mixture is lower than the geometric rate determined by the displacements of the piston in the cylinder between its bottom dead center (PMB) and its top dead center (TDC), and therefore below the expansion rate. .
• turbocharging which has the advantage of using as driving power of the compressor the energy of the exhaust gases which, otherwise, is not used.
• turbocharger One of the characteristics of a turbocharger is that it provides sufficient overpressure only from a certain engine rotation speed, that is to say from a certain energy level of the gases d exhaust, so that at low revs or at low engine loads, the rate of supercharging provided by the turbocharger is very low.
• the invention proposes an engine of the type seen above, characterized in that means are provided for delaying the closing of the communication between the intake circuit and the chamber combustion outside the engine operating modes corresponding to low intake pressures.
• the obturation of the intake circuit is delayed by delaying the closing command of at least one intake valve; - the delay in closing the intake valve is variable depending on engine operating parameters;
• each cylinder has at least two intake valves each connected by an independent conduit to the intake circuit, one of the intake valves is controlled to be closed with delay, and the intake conduit associated with this valve is provided with controlled valve means which are closed for a low inlet pressure;
• valve means The opening of the valve means varies according to engine operating parameters
• the winnowing means include a shutter with controlled opening.
• FIG. 1 is a partial schematic sectional view of part of an internal combustion engine according to the teachings of the invention.
• Fig ures 2 and 3 are two diagrams showing the valve lift control during the exhaust and intake times of the thermal cycle of such an engine, respectively in the case of low and high intake pressures;
• FIG. 1 shows a cylinder 1 0 of a four-stroke turbocharged internal combustion engine, the upper part of which forms a combustion chamber 12 delimited by a movable piston 14 and by a cylinder head 1 5.
• the cylinder re 1 0 is supplied with air / fuel mixture by an intake circuit 16 which opens into the combustion chamber 12 through an intake valve 1 8 whose movements are controlled by a camshaft (not shown) so to close or not to close the communication between the intake circuit 16 and the combustion chamber 12.
• the intake circuit 16 comprises, upstream of the valve 1 8, a turbocharger 1 1 of supercharging.
• An exhaust circuit 17 is provided for evacuating the burnt gases from the combustion chamber 12 through an exhaust valve 1 9 also controlled by a camshaft (not shown).
• a variable distribution system it is possible to extend the opening of the intake valve 18 by using a variable distribution system.
• Such systems are known and it is therefore possible to vary the instant of closing of the intake valve 1 8 as a function of various engine operating parameters such as its rotation speed, the pressure of the air / fuel mixture. in the intake circuit 16 and the accelerator position
• this variation may be continuous or discrete.
• valves 18, 19 are controlled according to the diagram in the Figure 2 and the intake valve 18 is controlled to be closed very quickly after the bottom dead center (PMB) of the piston 14 which marks the theoretical end of the intake time.
• PMB bottom dead center
• This first embodiment of the invention can be used with engines having one or more intake valves per cylinder.
• the second embodiment of the invention which is shown in Figure 4 is more particularly intended for engines having at least two intake valves per cylinder.
• the intake valve 1 8b being for example controlled to close relatively long after the bottom dead center (PMB) of the piston 14 representing the end of the theoretical admission time.
• PMB bottom dead center
• the two intake valves 1 8a, 1 8b are each provided with an independent intake duct 20a, 20b and the duct 20b of the inlet valve 18b controlled with a closing delay is provided with a shutter 22 controlled as a function of engine operating parameters.
• the flap 22 is closed and then closes the cond uit 20b so as to prevent any discharge of air / fuel mixture into the intake circuit 16.
• the flap 22 is controlled to be opened so as to allow such a discharge.
• this system avoids the installation of a heavy and complex variable distribution device while obtaining the desired Miller cycle.
• This device also has the advantage of reducing the passage section of the inlet gases at low loads, which improves their mixing and therefore promotes homogeneous combustion of the air / fuel mixture in the cylinder.
• the cylinder 10 continues to receive air / fuel mixture while the piston 14 begins to rise in the cylinder re, which is favorable to a good filling.

Landscapes

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

Applications Claiming Priority (3)

Publications (1)

Family

ID=9482812

Family Applications (1)

Country Status (4)

Family Cites Families (5)

• 1995
  • 1995-09-21 FR FR9511115A patent/FR2739138B1/fr not_active Expired - Fee Related
• 1996
  • 1996-09-20 EP EP96932622A patent/EP0851972A1/de not_active Withdrawn
  • 1996-09-20 WO PCT/FR1996/001468 patent/WO1997011260A1/fr not_active Application Discontinuation
  • 1996-09-23 AR ARP960104458A patent/AR003647A1/es unknown

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events