Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D15/00—Varying compression ratio
  • F02D15/02—Varying compression ratio by alteration or displacement of piston stroke
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B75/00—Other engines
  • F02B75/04—Engines with variable distances between pistons at top dead-centre positions and cylinder heads
  • F02B75/045—Engines with variable distances between pistons at top dead-centre positions and cylinder heads by means of a variable connecting rod length
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B75/00—Other engines
  • F02B75/04—Engines with variable distances between pistons at top dead-centre positions and cylinder heads
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B75/00—Other engines
  • F02B75/04—Engines with variable distances between pistons at top dead-centre positions and cylinder heads
  • F02B75/047—Engines with variable distances between pistons at top dead-centre positions and cylinder heads by means of variable crankshaft position
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B75/00—Other engines
  • F02B75/16—Engines characterised by number of cylinders, e.g. single-cylinder engines
  • F02B75/18—Multi-cylinder engines
  • F02B75/22—Multi-cylinder engines with cylinders in V, fan, or star arrangement
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D15/00—Varying compression ratio
  • F02D15/04—Varying compression ratio by alteration of volume of compression space without changing piston stroke

Definitions

• the present invention relates to a method and a device, reactive and consuming very little energy, for continuously optimizing the compression ratio, in particular of reciprocating piston engines.
• This invention is especially relevant for improving the energy efficiency of engines which are not used continuously at their maximum load or which use multiple fuels of different octane numbers.
• This invention is compatible with a very low level of pollution and is suitable in particular for reciprocating piston engines whose cylinders are arranged either flat, or in N, or in line.
• compression ratio designates the geometric compression ratio of an internal combustion engine with reciprocating pistons.
• Continuous optimization of the compression ratio is relevant for reducing fuel consumption and contributing to the greenhouse effect for areas of use where engines are not fully loaded and for engines that use multiple fuels d 'different octane numbers.
• Continuous optimization of the compression ratio is relevant for keeping an engine in compression ignition mode of a premix of oxidizer and fuel.
• Such a mode of operation described in particular in WO 99 42718 A, allows to achieve a very low emission level of nitrogen oxides.
• the optimization of the compression ratio is compatible with the usual systems for reducing nitrogen oxide emissions such as exhaust gas recycling systems (EGR) or catalysts for nitrogen oxides.
• EGR exhaust gas recycling systems
• Patent WO 95 29329 A discloses a device comprising two eccentrics at the head of each connecting rod. The angular setting of these two eccentrics is a function of the engine load and allows the distance between each piston and the corresponding cylinder head to be modified.
• One category of solutions consists in modifying the length of the connecting rod, for example by adding a joint which modifies the straightness of the connecting rod.
• Patents EP 0 520 637 A and DE 195 02 820 A can be classified in this category of solutions.
• the additional parts which transmit the forces between the pistons and the crankshaft crank pins must be designed and dimensioned accordingly to ensure the required reliability.
• the method according to the invention is therefore compatible with devices for which the operation induces a variation in the distance between the point of articulation and the axis of the corresponding crankpin of the crankshaft.
• the method according to the invention is also compatible with devices which do not allow the distance between the articulation point and the axis of the corresponding crankpin of the crankshaft to be varied.
• the method according to the invention also applies to internal combustion thermal engines also comprising an electronic device for calculating optimal values for controlling the operation of these engines, sensors for measuring the values of physical quantities which characterize the operation of these motors, devices for adjusting commands for the operation of these motors to the values calculated by the calculation device mentioned above.
• the process described above is supplemented, on the one hand by the calculation in the second phase: of the quantities of air and fuel admitted for combustion as well as of the trigger angle combustion, as a function of the values of physical quantities which characterize the operation of the motors measured in the first phase, in particular the compression ratio, on the other hand by the control in the third phase of the devices for obtaining the quantity of intake air, quantity of fuel admitted, combustion initiation angle, in order to make the values of these three controlled parameters converge towards the values calculated in the second phase as a function in particular of the compression ratio.
• the device according to the invention integrated into an internal combustion engine with reciprocating pistons driven by a main crankshaft comprising an eccentric placed between the foot of each connecting rod and the corresponding crankpin of the main crankshaft is characterized in that each eccentric placed between the foot of each connecting rod and the corresponding crankpin of the main crankshaft is oriented using a rod whose direction is articulated on a pivot.
• the axis of the sliding part of the rod is in a plane perpendicular to the axis of the main crankshaft
• the displacements of the pivot, of the slide or articulated arms are made in planes perpendicular to the axis of the main crankshaft
• the axis of the pivot is parallel to the axis of the main crankshaft.
• Each pivot which articulates the direction of a rod secured to an eccentric forms a crankpin of this orientation crankshaft and each articulated arm of the corresponding pendulum forms a lever connecting this crankpin to the corresponding journal of this orientation crankshaft.
• the crankshaft is guided and oriented by a guidance system.
• This guidance system comprises a frame articulated on an axis fixed relative to the casing and controlled in position.
• the fixed parts of the bearings of the orientation crankshaft are integral with this articulated frame.
• the guidance system and the orientation crankshaft are constructed to comply, during operation, with geometrical characteristics included within tolerances compatible with the possibilities of realization as well as with the proper functioning of the device and of the engine.
• the axis of articulation of the chassis coincides with the axis of the main crankshaft; - Each pivot and the axis of the orientation crankshaft are parallel to the axis of the main crankshaft; the displacements of each pivot are carried out along planes perpendicular to the axis of the main crankshaft; the length of the lever of each crankpin of the orientation crankshaft is equal to the length of the lever of the corresponding crankshaft belonging to the main crankshaft; - The orientation crankshaft is linked in rotation to the main crankshaft so that the crankpin levers of these two crankshafts are always parallel.
• the engine includes an electronic computer.
• the position of the slide or the articulated arms, for each eccentric placed between a connecting rod end and the corresponding crankpin of the main crankshaft, is calculated by the electronic computer, taking into account in particular the possibilities defined by the mechanical construction of the engine.
• the fourth list of characteristics described in this paragraph can complete the device according to the invention or its construction variant, alone or associated with any one of the three other lists of complementary characteristics mentioned above.
• an actuator uses a part of the exhaust gas fenthalpy to help modify the compression ratio.
• the device according to the invention in any of the versions described above, incorporates the characteristic described in the preceding paragraph.
• a hydraulic actuator makes it possible to actuate the device for modifying the compression ratio.
• a gas cylinder acts on a booster cylinder in order to provide hydraulic pressure to modify the compression ratio of the engine. This design offers a greater choice for placing the gas actuator.
• the eccentrics placed between the connecting rod ends and the crank pins of the main crankshaft are secured to one or more fingers and this or these fingers are all oriented towards a half-space defined by a plane secured to the eccentric, this plane containing the axis of the crank pin.
• two eccentrics are joined, with an angular offset, so that the axes of their internal diameter are coincident.
• FIG. 1 is a diagram which illustrates the characteristics of the method according to the invention.
• FIG. 7 represents two schematic cross-sectional views of an engine with cylinders arranged in line, the compression ratio modification mechanism of which comprises a rod which slides relative to the eccentric and which is integral with a part guided by the pivot;
• FIG. 8 shows a schematic cross-sectional view of an engine with cylinders arranged in a V, the compression ratio modification mechanism comprises a rod secured to the eccentric which slides relative to a balance; 9 shows a schematic view in cross section of an opposed engine having a modification mechanism of the compression ratio includes a rod integral with the eccentric which slides relative to a slider;
• the orientation crankshaft is guided and oriented by a guide system which comprises a chassis (60) articulated around an axis coincident with the axis of the main crankshaft (4).
• the bearings of the orientation crankshaft are fixed to the chassis (60).
• the guidance system and the orientation crankshaft are constructed to respect, during operation, geometric characteristics included within tolerances compatible with the possibilities of realization as well as with the proper functioning of the device and of the motor. These geometric characteristics are as follows: the displacements of each pivot (29a), (29b), (29c) are produced in the plane (9) perpendicular to the axis (1) of the main crankshaft (4), each pivot (29a ), (29b).
• FIG. 9 The mechanism for changing the compression ratio shown in FIG. 9 is driven by a hydraulic cylinder (93).
• This hydraulic cylinder is supplied by the pipes (55) and (56). It is linked to the slide (28) via the rod (92).
• Figures 4 and 5 show another way to realize the invention.
• Each of the two chambers (107a), (107b) of the booster cylinder (106) is connected to a hydraulic pipe (55) or (56) supplying the hydraulic cylinder (93) or the variable timing device (54) , via two parallel branches, one of which is fitted with a valve (108c), (108b) and the other with a valve (108a), (108d) and a non-return valve ( 109a), (109b).
• This non-return valve (109a), (109b) stops the flow of hydraulic liquid in the corresponding branch to the overpressure cylinder (106).
• the outlet pipes (105a), (105b) of the gas cylinder (103) are connected to the motor suction (20). This variant is not shown in the figures.
• the eccentrics (8), (8a), (8b) are formed by two half shells (121) and (122). This construction shown in Figures 11 to 14 facilitates assembly.

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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)
• Shafts, Cranks, Connecting Bars, And Related Bearings (AREA)

Applications Claiming Priority (5)

Publications (2)

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ID=26212525

Family Applications (1)

Country Status (8)

Families Citing this family (21)

Family Cites Families (27)

• 2000
  • 2000-11-28 WO PCT/FR2000/003324 patent/WO2001040641A1/fr active IP Right Grant
  • 2000-11-28 DE DE60017940T patent/DE60017940T2/de not_active Expired - Lifetime
  • 2000-11-28 US US10/148,393 patent/US6789515B1/en not_active Expired - Fee Related
  • 2000-11-28 JP JP2001542680A patent/JP4505170B2/ja not_active Expired - Fee Related
  • 2000-11-28 EP EP00985347A patent/EP1238189B1/de not_active Expired - Lifetime
  • 2000-11-28 ES ES00985347T patent/ES2237479T3/es not_active Expired - Lifetime
  • 2000-11-28 KR KR1020027006960A patent/KR100720327B1/ko not_active IP Right Cessation
  • 2000-11-28 AU AU21796/01A patent/AU2179601A/en not_active Abandoned

Non-Patent Citations (1)

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