US6499471B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic compensator for a piezoelectrical fuel injector
Assignee: Siemens Automotive Corp
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Filing: 2001-06-01
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Granted: 2002-12-31
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Expires: 2021-06-01
Abstract
Abstract A fuel injector comprises a body having a longitudinal axis, a piezoelectric actuator that has first and second ends, a needle coupled to the first end of the piezoelectric actuator, and a hydraulic compensator coupled the second end of the piezoelectric actuator. The piezoelectric actuator includes a plurality of piezoelectric elements along the axis between the first and second ends. The needle is movable between a first configuration permitting fuel injection and a second configuration preventing fuel injection. And the hydraulic compensator axially positions the piezoelectric actuator with respect to the body in response to temperature variation. Also, a method of compensating for thermal expansion or contraction of the fuel injector comprises providing fuel from a fuel supply to the fuel injector; and axially adjusting the piezoelectric actuator with respect to the body in response to temperature variation. The axially adjusting includes moving hydraulic oil through an orifice connecting first and second hydraulic oil reservoirs.
Inventors
- 👤 Jingming Jim Shen
- 👤 Bogdan Gromek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 17:39
CPC Classifications
F; F02; F02M; F02M61/00; F02M61/04; F02M61/08; F02M51/00; F02M51/06; F02M51/0603; F02M61/16; F02M61/167; F02M2200/00; F02M2200/26
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
138 words
A fuel injector comprising: a body having a longitudinal axis; a piezoelectric actuator having first and second ends, the piezoelectric actuator including a plurality of piezoelectric elements along the axis between the first and second ends; a needle coupled to the first end of the piezoelectric actuator, the needle being movable between a first configuration permitting fuel injection and second configuration preventing fuel injection; and a hydraulic compensator coupled to the second end of the piezoelectric actuator and axially positioning the piezoelectric actuator with respect to the body in response to temperature variation, the hydraulic compensator comprises: hydraulic oil; a first reservoir filled with the hydraulic oil; a second reservoir filled with the hydraulic oil; an orifice connecting the first and second reservoirs, the hydraulic oil moving through the orifice between the reservoirs in response to temperature variation.
Claim 2
Dependent Claim
138 words
A fuel injector comprising: a body having a longitudinal axis; a piezoelectric actuator having first and second ends, the piezoelectric actuator including a plurality of piezoelectric elements along the axis between the first and second ends; a needle coupled to the first end of the piezoelectric actuator, the needle being movable between a first configuration permitting fuel injection and second configuration preventing fuel injection; and a hydraulic compensator coupled to the second end of the piezoelectric actuator and axially positioning the piezoelectric actuator with respect to the body in response to temperature variation, the hydraulic compensator comprises: hydraulic oil; a first reservoir filled with the hydraulic oil; a second reservoir filled with the hydraulic oil; an orifice connecting the first and second reservoirs, the hydraulic oil moving through the orifice between the reservoirs in response to temperature variation.
Claim 3
Dependent Claim
15 words
The fuel injector according to claim 1 , wherein the hydraulic oil comprises silicon oil.
Claim 4
Dependent Claim
38 words
The fuel injector according to claim 1 , wherein the hydraulic compensator further comprises: a first piston fixed with respect to the second end of the piezoelectric actuator stack, the piston defines a portion of the first reservoir.
Claim 5
Dependent Claim
59 words
The fuel injector according to claim 3 , wherein the hydraulic compensator further comprises: a bellows defining at least a portion of the second reservoir; and a compression spring acting on the bellows to displace the hydraulic oil from the second reservoir, through the orifice, to the first reservoir, and to the first reservoir for displacing the first piston.
Claim 6
Dependent Claim
31 words
The fuel injector according to claim 4 , wherein the hydraulic compensator further comprises: a screw operatively connected to the compression spring and adjusting a spring factor of the compression spring.
Claim 7
Dependent Claim
55 words
The fuel injector according to claim 3 , wherein the hydraulic compensator further comprises: a second piston defining a portion of the second reservoir; and a compression spring acting on the second piston to displace the hydraulic oil from the second reservoir, through the orifice, and to the first reservoir for displacing the first piston.
Claim 8
Dependent Claim
31 words
The fuel injector according to claim 6 , wherein the hydraulic compensator further comprises: a screw operatively connected to the compression spring and adjusting a spring factor of the compression spring.
Claim 9
Dependent Claim
69 words
The fuel injector according to claim 1 , wherein the orifice comprises a diameter that permits the hydraulic oil to move from the second resevoir to the first reservoir in response to temperature variation during thermal expansion of the fuel injector body and substantially prevents the hydraulic oil to move from the first resevoir to the second reservoir in response to movement due to actuation of the piezoelectric actuator.
Claim 10
Dependent Claim
19 words
The fuel injector according to claim 1 , wherein the piezoelectric actuator is substantially unaffected by the temperature variation.
Claim 11
Independent Claim
134 words
A method of compensating for thermal expansion or contraction of a fuel injector, the fuel injector a body having a longitudinal axis, a piezoelectric actuator having first and second ends, the piezoelectric actuator including a plurality of piezoelectric elements along the axis between the first and second ends, a needle coupled to the first end of the piezoelectric actuator, the needle being movable between a first configuration permitting fuel injection and a second configuration preventing fuel injection, and a hydraulic compensator coupled the second end of the piezoelectric actuator, the method comprising: providing fuel from a fuel supply to the fuel injector; and axially adjusting the piezoelectric actuator with respect to the body in response to temperature variation, the axially adjusting including moving hydraulic oil through an orifice connecting the first and second reservoirs.
Claim 12
Independent Claim
134 words
A method of compensating for thermal expansion or contraction of a fuel injector, the fuel injector a body having a longitudinal axis, a piezoelectric actuator having first and second ends, the piezoelectric actuator including a plurality of piezoelectric elements along the axis between the first and second ends, a needle coupled to the first end of the piezoelectric actuator, the needle being movable between a first configuration permitting fuel injection and a second configuration preventing fuel injection, and a hydraulic compensator coupled the second end of the piezoelectric actuator, the method comprising: providing fuel from a fuel supply to the fuel injector; and axially adjusting the piezoelectric actuator with respect to the body in response to temperature variation, the axially adjusting including moving hydraulic oil through an orifice connecting the first and second reservoirs.
Claim 13
Dependent Claim
38 words
The method according to claim 10 , wherein the axially adjusting comprises displacing a piston defining a portion of the first reservoir, and the piston displacing the second end of the piezoelectric actuator with respect to the body.
Claim 14
Dependent Claim
31 words
The method according to claim 11 , wherein the axially adjusting further comprises compressing a spring operatively engaging a bellows, the bellows defining at least a portion of the second reservoir.
Claim 15
Dependent Claim
20 words
The method according to claim 12 , wherein the axially adjusting further comprises adjusting a spring factor of the spring.
Claim 16
Dependent Claim
31 words
The method according to claim 11 , wherein the axially adjusting further comprises compressing a spring operatively engaging a second piston, the second piston defining a portion of the second reservoir.
Claim 17
Dependent Claim
20 words
The method according to claim 14 , wherein the axially adjusting further comprises adjusting a spring factor of the spring.
Claim 18
Dependent Claim
32 words
The method according to claim 10 , the method further comprising: substantially preventing the hydraulic oil to move between the first and second reservoirs in response to actuation of the piezoelectric actuator.
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