Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D9/00—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits
  • F02D9/04—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits concerning exhaust conduits
  • F02D9/06—Exhaust brakes
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D11/00—Arrangements for, or adaptations to, non-automatic engine control initiation means, e.g. operator initiated
  • F02D11/06—Arrangements for, or adaptations to, non-automatic engine control initiation means, e.g. operator initiated characterised by non-mechanical control linkages, e.g. fluid control linkages or by control linkages with power drive or assistance
  • F02D11/08—Arrangements for, or adaptations to, non-automatic engine control initiation means, e.g. operator initiated characterised by non-mechanical control linkages, e.g. fluid control linkages or by control linkages with power drive or assistance of the pneumatic type

Definitions

• the present invention relates to a retarder device mounted in the exhaust gas circuit of a vehicle equipped with a combustion engine, comprising at least one valve provided with a movable shutter and a control cylinder for this shutter, this cylinder comprising a movable piston provided with a rod coupled to said movable obturator, and comprising at least one device for balancing the back pressure exerted by the obturator on the gases, this balancing device being arranged to enter into action when the shutter (7) is in the closed position and from a predetermined back pressure threshold and to reopen the shutter (7) with a reopening degree I as soon as the back pressure reaches said threshold, so as to create an appropriate exhaust gas leakage rate to regulate this back pressure regardless of the engine speed.
• This type of retarder is well known in particular in the field of industrial vehicles equipped with a combustion engine. Given their high inertia, these vehicles require, in addition to their own braking system, a retarder device housed in the exhaust gas circuit, preferably between the engine and the silencer, and generally mounted at the outlet of the turbocharger. powered by the exhaust manifold. It is usually controlled by a pedal actuated by the driver's left foot to prevent the driver from disengaging at the same time.
• This retarder device generates back pressure in the exhaust circuit. This back pressure is higher or lower depending on the position of the shutter and its degree of reopening. It has the effect of slowing down the engine and therefore of completing the braking of the vehicle. The higher the back pressure, the more effective the deceleration.
• this back pressure must be limited to the maximum set pressure allowable by the exhaust manifold, in order to avoid reopening of the intake valves.
• This back pressure naturally depends on the pressure of the exhaust gases exerted on the shutter which is an asymptotic function of the engine speed. Consequently, for each engine speed corresponds a level of back pressure and therefore a level of deceleration. We are currently trying to make this function constant and at most equal to the maximum admissible set pressure whatever the engine speed and from low speeds, in order to optimize the deceleration.
• an exhaust modulator device comprises in a shutter shutter two leakage holes closed by spring blades having different rigidities.
• a first leaf spring opens a first leak hole and releases part of the exhaust gases.
• a second level of back pressure is reached, the second leaf spring opens a second leak hole, thereby increasing the flow of exhaust gases.
• This device makes it possible to limit the back pressure but generates deceleration stages. It is therefore not optimal.
• the leaf springs are subjected to temperature constraints and the attack of exhaust gases. As a result, their functioning deteriorates over time, thus affecting their opening and closing performance.
• the publication US-A-4,669,585 describes a technique similar to that above but adapted to a guillotine valve, the overall height of which is much greater than that of a butterfly valve.
• the counterpressure balancing device comprises an opening in the shutter closed by a plate coupled to the end of an actuator rod which can lie in the piston against the action of a spring when the back pressure reaches a certain threshold. exhaust gas only a small contact surface, which reduces the efficiency of the retarder.
• this device is directly subjected to the attacks of the exhaust gases and can, therefore, seize up or be damaged prematurely, which reduces the reliability of the device.
• This device is also complex and expensive to implement. It also undergoes parasitic forces, the back pressure acting perpendicular to the movement of said plate further reducing the efficiency and reliability of the device.
• the object of the present invention is to improve current retarder devices by proposing a simple, compact back pressure equalization device, of reduced cost, making it possible to obtain constant and maximum deceleration performance whatever engine speed while guaranteeing reliability and operating stability over time, without risk of damage due to aggression from exhaust gases and high temperature, protected from any attack from outside the engine (splashing water , sludge, oil residue, etc.), and without affecting the inertia of the retarder and therefore the efficiency of the opening and closing of the shutter.
• Another aim is to be able to easily and at low cost equip the retarder devices already in service by an after-sales marketing.
• a retarder device as defined in the preamble and characterized in that the straightening device is integrated into the control cylinder and disposed between two separate and coaxial parts of the cylinder rod, at least one part being arranged to move from one stroke C relative to the other, this stroke C corresponding to the degree of reopening I and being controlled by at least one calibrated spring member disposed between the two distinct parts of this rod.
• one of the parts is constituted by the movable piston and the other part is constituted by the rod itself.
• the piston can comprise a coaxial cavity and the rod can comprise a head housed in said cavity, the calibrated spring member being disposed in the cavity at the rear of the head.
• the piston consists of two assembled parts, the cavity extending inside the two parts.
• the spring member is calibrated to a value such that it compresses from a force corresponding to said predetermined back pressure threshold.
• the maximum stroke C of the cylinder rod can be between 0 and 10 mm and is preferably equal to 5 mm.
• the shutter is rotatable and the degree of reopening I is an angle ⁇ , the maximum value of which is between 0 and 20 ° and preferably equal to 10 °.
• the cavity has a length at least equal to the sum of the length of the compressed calibrated spring member, the thickness of the head of the rod and the maximum stroke C of the rod.
• the axis of rotation A of the shutter is distinct from the axis of symmetry B of said shutter by an interval d, this interval d being between 0.5 and 5 mm.
• the jack has two separate bearings, arranged to guide the rod axially, one bearing being provided in the piston and the other bearing in a fixed ring which closes the jacketing of the jack.
• FIG. 1 represents an overall perspective view of a retarder device according to the invention mounted at the outlet of a turbocharger
• FIG. 2 is a view in axial section of the retarder device according to the invention.
• Figures 3 to 5 are top sectional views showing the retarder device respectfully at rest - the shutter open, at work - the shutter closed and balanced - the shutter slightly open.
• the retarder device 1 is conventionally mounted in the exhaust circuit of a generally industrial vehicle and equipped with a combustion engine, at the outlet of a turbocharger TC powered by an EC exhaust manifold which recovers the gases from said engine (not shown).
• the retarder device 1 comprises a valve 2 controlled by a control member 3.
• the valve 2 comprises a body 4 defining a channel 5 for the passage of the exhaust gases in the direction of the arrows F and a bore 6 for a movable shutter 7 mounted in said body 4 transversely to said channel 5 intended to retain the gases upstream when it is in the closed position.
• the body 4 has at its ends two mounting flanges 4a, 4b intended to receive, upstream, a corresponding flange of the turbocharger TC and, downstream, a corresponding flange of the exhaust duct (not shown).
• the mounting flanges 4a, 4b can be replaced by any other equivalent device, such as clamps, etc.
• the movable shutter 7, which is shown, is a butterfly flap mounted on a shaft 8 of axis A, this shaft having an upper end which passes through said body 4 to be coupled to said control member 3.
• the axis A corresponding to the axis of rotation of the butterfly flap 7 is distinct from the axis of symmetry B of said flap and distant by an interval d which can vary from 0.5 to 5 mm depending on the size of the retarder. The reasons for this misalignment will be explained below. Of course, any other form of shutter is possible such as a bushel, a ball or a drawer.
• the body 4 of the valve 2 comprises a vacuum cellar 4 'which consists of a bent conduit produced by molding inside the body and located on the passage of the shaft 8.
• This conduit has a blind upstream end disposed near the shaft 8 and a downstream end opening into the channel 5 downstream of the shutter. It provides effective sealing of the retarder 1 between the shaft 8 and the body 4. In fact, when the shutter 7 is closed, if exhaust gases seep between these two parts, they are automatically diverted and evacuated by the duct 4 ', which by the difference in pressure between the upstream and downstream of the shutter acts as a vacuum cleaner, hence its name: vacuum cellar.
• the control member 3 is a jack 9, which can be hydraulic, pneumatic or electric, arranged outside said body 4 and therefore not subject to exhaust gases.
• This jack 9 is mounted on a support 10 by a screw-nut system 9 'defining a fixed axis D and comprises an internal movable piston 11 (cf. Fig. 3 to 5) provided with an external rod 12 coupled to the shaft 8 of the shutter 7 by a ball 13 and a lever 14, the ball 13 defining a hinge axis E.
• the points corresponding to axes A, D and E define a triangle which determines the kinematics of opening and closing of the butterfly flap 7 as well as the lengths of the lever 14 and of the rod 12 of the jack. In no case should these points be aligned.
• the support 10 of the jack 9 is positioned on the body 4 of the valve 2 and a seal 10 'is provided around the shaft 8 to further avoid any risk of leakage of exhaust gases outside the retarder 1.
• the retarder device 1 is controlled by the driver of the industrial vehicle by means of a control pedal. In normal vehicle operation, the retarder device 1 is at rest, so the shutter 7 is open (cf.
• the jack 9 is supplied with a pressurized fluid, the rod 12 extends and causes the shutter 7 to close (cf. FIG. 4) thus retaining the gases and generating a back pressure which causes the engine slowing down and therefore a decrease in vehicle speed. It should be noted that even in the closed position, the shutter 7 lets escape a reduced flow of exhaust gases to avoid any risk of blockage and dangerous overpressure for the equipment located upstream.
• FIGS. 3 to 5 illustrate the different positions of the retarder device 1 in top view with the representation in section of the control jack 9.
• Figure 3 shows the retarder device 1 in its rest position. The jack is not supplied, the piston 11 is located near the orifice 15 for supplying the pressurized fluid, the rod 12 is retracted and the shutter 7 is in the open position, that is to say oriented in parallel the flow of exhaust gases.
• FIG. 4 shows the retarder device 1 in its working position.
• the jack 9 is supplied, the piston 11 moves in one stroke C, the rod 12 comes out of the same stroke C causing the shutter 7 to pivot a quarter turn.
• the shutter 7 is then in the closed position, that is to say oriented perpendicular to the flow of the exhaust gases and generating the back pressure.
• the shutter 7 and the bore 6 of this shutter are arranged to allow a very small gas leak to escape.
• the piston 11 is mounted in the jacket of the jack 9 by an O-ring 16 ensuring sealing and on the rod 12 by a paher 17.
• a fixed ring 18 closes the jacket of the jack 9 and guides the rod 12 in a paher 19.
• This rod 12 is therefore guided axially at its two ends by the two bearings 17, 19, which are self-lubricated and which provide it with a sufficient guide surface to ensure a uniform movement, always in the axis and without risk of blockage. .
• Two superposed return springs 20, 21, placed in opposition and coaxial are provided between this fixed ring 18 and the piston 11 to return the piston 11 to the rest position as soon as the supply of the pressurized fluid stops.
• These two return springs 20, 21 can also be replaced by a single return spring or by any equivalent means, depending on the type of retarder.
• the piston 11 is limited in its stroke by a stop formed when the two pads 17, 19 come into contact, the return springs 20, 21 being compressed.
• These return springs 20, 21 are determined so that by being compressed, their turns are never contiguous, in order to limit the fatigue of these springs and to avoid that they alone form said abutment. These return springs 20, 21 are mounted and guided on corresponding shoulders 11 ', 11 "and 18', 18" provided respectively on the piston 11 and the fixed ring 18.
• FIG. 5 represents the retarder device 1 in its equilibrium position.
• the jack 9 is always supplied with the pressurized fluid, the piston 11 is in the same position as that of FIG. 4 and the rod 12 is extended.
• the gas pressure upstream of the shutter 7 has increased beyond a back pressure threshold, which is at most equal to the maximum admissible back pressure value and which is determined by a shredding device 25 described below and authorizing the reopening partUe and limited to a degree of reopening I of the shutter 7 to create a greater gas leakage.
• the shutter 7 is placed in an equilibrium position limited by its degree of reopening I ensuring a constant and maximum deceleration effect since it corresponds to the counter - predetermined set pressure which can be the maximum permissible back pressure by the CE exhaust manifold.
• the shredding device 25 is integrated and housed in the cylinder 9. It comprises the rod 12 of the cylinder which is dissociated from the piston 11 and a calibrated spring member 26 interposed between the rod and the piston.
• the calibrated spring member 26 is, in this case, a compression spring but can be constituted by any other suitable spring element.
• a cavity 27 is provided coaxially in the piston 11 to receive said spring member 26 and the corresponding end of the rod 12 forming a head 28 with a diameter greater than that of the rod.
• the cavity 27 has a length at least equal to the sum of the length of the calibrated compressed spring member 26, the thickness of the head 28 of the rod and a stroke C corresponding to the recoil stroke of the rod 12.
• the integration of the balancing device 25 in the jack 9 requires the rehsation of the piston 11 into two parts 11a, 11b assembled by screwing or any other equivalent means such as for example crimping, the cavity 27 being provided inside. of both parties.
• the spring member 26 pushes the rod 12 which is stopped in translation by its head 28 while pressing on the bottom of the cavity 27.
• This spring member 26 is calibrated to resist a compressive force corresponding to the counter threshold -pressure predetermined at the shutter 7, equal to or less than the maximum permissible back pressure by the CE exhaust manifold. Beyond this threshold, the spring member 26 compresses and allows the rod 12 of the stroke C to retreat under the effect of the pressure of the exhaust gases exerted on the shutter 7.
• the axis of rotation A of the shutter 7 is off-axis with respect to its axis of symmetry B, thus creating a torque allowing its reopening under the thrust force caused by the exhaust gases.
• the stroke C of the rod 12 authorizes the reopening of the shutter 7 by a degree of reopening I, corresponding in this case, to an angle ⁇ , thereby generating a greater exhaust gas leakage rate.
• the maximum stroke C is delimited by the part 11a of the piston and the head 28 of the rod when this head 28 abuts at the bottom of the cavity 27.
• it can be between 0 and 10 mm and preferably equal to 5 mm, which corresponds to a maximum degree of reopening I whose maximum angle ⁇ is between 0 and 20 ° and preferably equal at 10 °.
• this reopening angle ⁇ varies as a function of the exhaust gas pressure between its minimum and maximum values, 0 and 10 ° for example, which makes it possible to guarantee a constant back pressure. and at most equal to the maximum admissible pressure set by the CE exhaust coUector.
• This equalization device 25 therefore makes it possible to control the pressure of the gases upstream of the shutter by balancing the forces at the level of the rod 12 of the jack 9.
• the invention makes it possible to improve the current retarder devices by proposing a simple, inexpensive, efficient, compact stretching device 25 incorporated in the control jack 9 which is delocalized with respect to the circuit. exhaust.
• the retarder and balancing functions are thus dissociated.
• the control cylinder 9 equipped with the balancing device 25 and the shredding device itself are neither subjected to high temperatures and to aggressions from the exhaust gases, nor to aggressions external to the engine.
• the angle-cutting device 25 being integrated into the jack 9 does not generate any parasitic load on the rod of the jack which can have a negative influence on its reaction time when the shutter is opened and closed.
• U can be offered in after-sales to equip existing retarder devices and can be installed very easily without the need to dismantle valve 2.
• the present invention is not limited to the example of reahsation described but extends to any modification and variant obvious to a person skilled in the art.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Control Of Throttle Valves Provided In The Intake System Or In The Exhaust System (AREA)
• Braking Arrangements (AREA)
• Transmission Of Braking Force In Braking Systems (AREA)
• Exhaust Gas After Treatment (AREA)
• Valve Device For Special Equipments (AREA)
• Controls For Constant Speed Travelling (AREA)

Applications Claiming Priority (3)

Publications (2)

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ID=9525680

Family Applications (1)

Country Status (11)

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Family Cites Families (6)

• 1998
  • 1998-04-22 FR FR9805212A patent/FR2777945B1/fr not_active Expired - Fee Related
• 1999
  • 1999-04-22 CA CA002294097A patent/CA2294097C/fr not_active Expired - Fee Related
  • 1999-04-22 US US09/446,421 patent/US6273059B1/en not_active Expired - Fee Related
  • 1999-04-22 AT AT99915821T patent/ATE231952T1/de not_active IP Right Cessation
  • 1999-04-22 DE DE69905112T patent/DE69905112T2/de not_active Expired - Lifetime
  • 1999-04-22 KR KR1019997012166A patent/KR20010020490A/ko not_active Application Discontinuation
  • 1999-04-22 WO PCT/FR1999/000965 patent/WO1999054611A1/fr not_active Application Discontinuation
  • 1999-04-22 RU RU2000100819/06A patent/RU2218470C2/ru not_active IP Right Cessation
  • 1999-04-22 TR TR1999/03200T patent/TR199903200T1/xx unknown
  • 1999-04-22 AU AU34265/99A patent/AU3426599A/en not_active Abandoned
  • 1999-04-22 EP EP99915821A patent/EP0991857B1/de not_active Expired - Lifetime

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