Coated compressor diffuser

Details Coated compressor diffuser Coated compressor diffuser

1999-07-19

2001-04-24

Verdier, Christopher (Department: 3745)

Internal-combustion engines

High tension ignition system

Using capacitive storage and discharge for spark energy

C060S751000, C417S407000, C415S200000, C415S915000, C029S888020, C029S888021, C029S889200

Reexamination Certificate

active

06220234

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to an internal coating for increasing the efficiency of a centrifugal compressor. More specifically, the invention relates to a powder paint coating within the volute of a turbocharger.
There is a continuing interest and importance to improving the thermal efficiency of the internal combustion engine. One of the most efficient forms of internal combustion engines is a diesel engine with a turbocharger. It is well known that the turbocharger utilizes waste heat of the exhaust gas to drive a compressor for compressing the intake air accepted by the diesel engine.
The role of the turbocharger in improving the brake specific fuel consumption (BSFC) of a diesel engine includes not just efficiently extracting power from the exhaust gas, but also using that power to efficiently compress the intake air. One general rule of thumb is that each one percent improvement in the efficiency of the turbocharger compressor relates to a one-third percent improvement in the BSFC of the engine.
One of the problems with centrifugal compressors of turbochargers is that the centrifuging action of the compressor provides air at high velocities into a diffuser. Although the diffuser, which is also called a volute on a turbocharger, slows the air exiting from the blades of the compressor, there is still a portion of the flowpath of the diffuser in which the high velocity air scrubs over the walls of the flowpath. This scrubbing action is aerodynamic drag of the air flowing over the wall. This drag reduces the total pressure of the air and increases the total temperature of the air, and thereby reduces the efficiency of the compressor.
There are techniques for smoothing the walls of the diffuser and thereby increasing the efficiency of the compressor. One such technique is to fabricate the volute from smooth, wrought materials, but this greatly increases the cost of the diffuser. It is more common to cast the diffuser so as to make it affordable. In some applications, sand casting is a preferred technique. However, even with selection of fine grain sand, the as-cast surfaces often have a surface roughness in excess of 250 microinches. This as-cast surface can be further machined as to improve its smoothness, although this additional machining operation necessarily increases the cost of the diffuser. One such technique is extrude honing.
What is needed is a technique for increasing the efficiency of centrifugal compressors in a cost-effective manner. The present invention does this in a novel and unobvious way.
SUMMARY OF THE INVENTION
Briefly describing one aspect of the present invention there is provided an apparatus comprising an internal combustion engine, a turbocharger, and a coating. The internal combustion engine produces exhaust gas. The turbocharger includes a turbine and a compressor. The turbine is powered by the exhaust gas, and the turbine powers the centrifugal compressor. The turbocharger defines a flowpath for slowing the air exiting from the compressor. There is a coating of heat-resistant powder paint along a portion of the flowpath. The coating provides a smooth surface to reduce the aerodynamic drag of the air flowing within the turbocharger.
Briefly describing another aspect of the present invention there is provided an apparatus comprising a centrifugal compressor, a cast diffuser, and a coating. The centrifugal compressor compresses gas. The cast diffuser defines an internal flowpath receiving compressed gas from the centrifugal compressor. There is a coating of heat-resistant paint on the cast diffuser along the portion of the internal flowpath.
Briefly describing another aspect of the present invention there is provided a method for improving the efficiency of a compressor. The method includes providing a compressor for compressing gas and a flowpath for the compressed gas. The method also includes coating a portion of the flowpath with a heat resistant powder paint and reducing the surface roughness of the portion of the flowpath.
These and other aspects of the present invention will be apparent from the following description of the preferred embodiment, the drawings and the claims.


REFERENCES:
patent: 1504736 (1924-08-01), Brown
patent: 3346175 (1967-10-01), Wiles
patent: 3764373 (1973-10-01), Speirs et al.
patent: 3998716 (1976-12-01), Masar et al.
patent: 4066806 (1978-01-01), Speirs et al.
patent: 4190686 (1980-02-01), Muis
patent: 4826401 (1989-05-01), Clark et al.
patent: 4988266 (1991-01-01), Nakamura et al.
patent: 5064315 (1991-11-01), Samejima et al.
patent: 5281484 (1994-01-01), Tank et al.
patent: 5441763 (1995-08-01), Kuo
patent: 5472315 (1995-12-01), Alexander et al.
patent: 5708039 (1998-01-01), Daly et al.
patent: 1098876 (1968-01-01), None
patent: 2195920 (1988-04-01), None
Permalux Powder Coating—General Technical Data Sheet: printed from Permalux web site: http://www.permalux.com/en/ABC.htm Jan. 12, 1999, 3 pages.
Permalux Powder Coating—ABC About Powder Coating: printed from Permalux web site: http://www.permalux.com/en/tech.htm Jan. 12, 1999, 2 pages.
“Belzona Superglide” Technical Leaflet, 2 pages (no date).

Affiliated with

Also associated with

Rating

Coated compressor diffuser does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Coated compressor diffuser, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Coated compressor diffuser will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2500205