Exhaust gas turbocharger for an internal-combustion engine

Details Exhaust gas turbocharger for an internal-combustion engine Exhaust gas turbocharger for an internal-combustion engine

1999-02-11

2001-05-01

Verdier, Christopher (Department: 3745)

Rotary kinetic fluid motors or pumps

Selectively adjustable vane or working fluid control means

Upstream of runner

C060S602000, C029S889100, C029S889200

Reexamination Certificate

active

06224333

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to an exhaust gas turbocharger for an internal-combustion, and more particularly, to a turbocharger having a turbine wheel which is arranged in the housing of the exhaust gas turbocharger and to which exhaust gas can be fed by way of a flow duct constructed in the housing, and having a variable baffle for adjusting a flow cross-section of the flow duct.
DE 195 43 190 A1 discloses an internal-combustion engine which has an exhaust gas turbocharger with a variable turbine geometry. On a housing of the turbine of the turbocharger, an adjustable baffle is arranged which has guide blades between which flow ducts for the exhaust gas are constructed. A control element provides adjustment of the guide blades between an opening position with the lowest possible reduction of the flow cross-section of a flow duct feeding exhaust gas and a ram position with the highest possible reduction of the flow cross-section. In order to obtain a high braking effect during the braking operation of the internal-combustion engine, the baffle is changed to its ram position, whereupon an excess pressure builds up in the section between the cylinders and the exhaust gas turbocharger. The brake pressure results in a rise of air flow in the cylinder and counteracts the compression of the gas in the cylinder.
Simultaneously, exhaust gas flows at a high velocity through the flow ducts between the guide blades and acts upon the turbine wheel whose power is transmitted to the compressor which builds up an excess pressure in the intake system and feeds it to the cylinder.
The cylinder is therefore acted upon with an increased charging pressure on the input side. A quasi-static excess pressure exists on the output side between the cylinder outlet and the exhaust gas turbocharger. This excess pressure counteracts the blowing-off of the air compressed in the cylinder into the exhaust gas piping. In the braking operation, the piston must therefore carry out compression work during the compression stroke against the high excess pressure in the exhaust gas piping, whereby a strong braking effect is achieved.
DE 43 30 487 C1 also shows a turbine with a variable turbine geometry. The turbine has a radial and a semiaxial ring nozzle. A stationary baffle is arranged in the semiaxial ring nozzle, and a variable baffle with rotatable guide blades is arranged in the radial ring nozzle. In addition, a ring, which is contoured in a fluidically advantageous manner, is arranged on the stationary baffle, is situated between the semiaxial and the radial ring nozzle and forms a stationary non-adjustable component of the turbine.
SUMMARY OF THE INVENTION
An object of the present invention is to equip exhaust gas turbochargers with a braking function at low manufacturing and mounting expenditures. In particular, it is to be possible with the present invention to retrofit existing exhaust gas turbochargers with a braking function.
According to the present invention, the foregoing objects have been achieved by providing that the baffle is movably accommodated in a matrix, the baffle and the matrix form a ring-shaped exchangeable braking module, and the matrix is detachably held on the housing and surrounds an outer contour of the turbine wheel by means of a defined gap.
By combining the components determining the braking function to form a braking module, the present invention makes it possible to provide new exhaust gas turbochargers as well as exhaust gas turbochargers which have been in operation with a braking function. The engine braking performance and the performance characteristics of the engine brake can be influenced by a simple exchange of the braking module.
Furthermore, the present invention also makes it possible to exchange within a module only the baffle and the matrix in which the baffle is guided in order to obtain in this manner an adaptation of the braking module to the respective geometry of the turbine wheel. As the result of the adaptation of certain components of the braking module to the geometry of differently constructed exhaust gas turbochargers, the braking module can be used for various exhaust gas turbochargers with only a few modifications.
The engine braking performance is achieved by the blocking or reduction of the flow cross-section by the adjustable baffle. An engine brake flap arranged behind the turbine is, however, not required and would even have a disturbing effect, which provides more mounting space.
The baffle can be advantageously axially adjusted between the opening position and the ram position so that, for changing into the ram position, the baffle must only be moved axially into the flow duct. The axially adjustable baffle is distinguished by a simple kinematic handling.
The baffle and the matrix are arranged in a ring shape around the turbine wheel in order to be able to block the ring nozzle of the normally spiral-shaped flow duct by way of which the exhaust gas can be fed from the exhaust gas piping of the turbine and in order to be able to build up the ram pressure required for the engine brake. In this embodiment, the guide blades are arranged in a ring and are preferably held on a carrier ring which provides an axial guidance in the matrix and can be acted upon by suitable control elements in the direction of the opening position or the ram position.
The carrier ring preferably has an approximately U-shaped cross-section which has a high stability and, in addition, may extend along the matrix as well as along the opposite wall in the housing of the exhaust gas turbocharger. The wall of the carrier ring to which the guide blades are fastened may have compensating bores in order to reduce or avoid an air cushion between this wall and the housing of the exhaust gas turbocharger. The air cushion would otherwise affect the adjusting movement during the axial adjusting of the baffle.
A removable lid is preferably provided on the housing so that the braking module, particularly the matrix, can be clamped to the housing and can be removed as required. For a secure receiving of the braking module, anchoring devices are provided for detachably fastening the matrix to the housing.
The baffle and/or the matrix can be constructed as a precision casting or as a sintered part which meets high precision requirements and is well suitable for being machined.


REFERENCES:
patent: 2784675 (1957-03-01), Farrell
patent: 2861774 (1958-11-01), Buchi
patent: 3303998 (1967-02-01), Koff et al.
patent: 4265589 (1981-05-01), Watson et al.
patent: 4582466 (1986-04-01), Szczupak
patent: 4886416 (1989-12-01), Wunderlich
patent: 5941684 (1999-08-01), Parker
patent: 668 455 (1988-12-01), None
patent: 4303521 (1994-05-01), None
patent: 43 30 487 (1995-01-01), None
patent: 195 43 190 (1997-05-01), None
patent: 0 034 915 (1981-09-01), None
patent: 227475 (1987-07-01), None
patent: 487193 (1992-05-01), None
patent: 0 654 587 (1995-05-01), None
patent: 624777 (1989-11-01), None
patent: 89/11583 (1989-11-01), None
European Search Report for EP 99100678.4, dated Jul. 14, 1999.

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