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US6158413A Expired / Lapsed US ⏱️ 0.0 years remaining

Direct injection diesel engine

Assignee: Nissan Motor Co Ltd
•
Filing: 2000-03-14
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Granted: 2000-12-12
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Expires: 2020-03-14
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Abstract

Abstract A fuel injection timing of a fuel injector (22) of a direct injection diesel engine is retarded to compression top dead center or even later. All of the required fuel injection amount is injected by the fuel injector (22) in an ignition delay period. The oxygen concentration in the combustion chamber (14) is decreased by exhaust gas recirculation. A swirl is set up in the combustion chamber (14) by a variable swirl generator (31). The compression ratio of the engine is preferably set to 15 or less, the vertical gas velocity in the combustion chamber is reduced by adopting a shallow piston cavity, and the cylinder internal maximum pressure is suppressed to 12 MPa or less.

Inventors

  • 👤 Shuji Kimura
  • 👤 Eiji Aiyoshizawa

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-31 17:16
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/30; F02D41/3011; F02D41/3017; F02D41/3035; F01; F01L; F01L9/00; F01L9/10; F02B; F02B23/00; F02B23/02; F02B23/06; F02B23/0696; F02B3/00; F02B3/06; F02D41/38; F02D41/40; F02D41/401; F02M; F02M26/00; F02M26/13; F02M26/22; F02M26/23; F02M26/27; F02M26/28; F02B2275/00; F02B2275/14; F02B23/0618; F02B23/0621; F02D41/0025; F02D41/0047; F02D41/005; F02D41/0057; F02M26/02; F02M26/04; F02M26/05; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12; Y02T10/40

Claims Analysis

Total Claims: 15
Claim 1
Independent Claim 123 words
A direct injection diesel engine which directly injects fuel into a combustion chamber, comprising: a cylinder; a piston forming the combustion chamber in the cylinder; a fuel injector which starts injection of fuel at a timing not before compression top dead center of the piston, and finishes the injection of all of a required amount of fuel during an ignition delay period; an exhaust recirculation passage which decreases an oxygen concentration in the combustion chamber by mixing part of the exhaust gas discharged from the combustion chamber with intake air of the combustion chamber; and a squish suppressing mechanism which suppresses a squish formed in the combustion chamber; wherein a maximum pressure in the combustion chamber is set not greater than twelve Megapascals.
Claim 2
Dependent Claim 123 words
A direct injection diesel engine which directly injects fuel into a combustion chamber, comprising: a cylinder; a piston forming the combustion chamber in the cylinder; a fuel injector which starts injection of fuel at a timing not before compression top dead center of the piston, and finishes the injection of all of a required amount of fuel during an ignition delay period; an exhaust recirculation passage which decreases an oxygen concentration in the combustion chamber by mixing part of the exhaust gas discharged from the combustion chamber with intake air of the combustion chamber; and a squish suppressing mechanism which suppresses a squish formed in the combustion chamber; wherein a maximum pressure in the combustion chamber is set not greater than twelve Megapascals.
Claim 3
Dependent Claim 23 words
A direct injection diesel engine as defined in claim 1, wherein a compression ratio of the engine is set not greater than fifteen.
Claim 4
Dependent Claim 49 words
A direct injection diesel engine as defined in claim 1, wherein the piston comprises a piston pin, and a distance from a center of the piston pin to a top surface of the piston is set not greater than forty five percent of a bore diameter of the cylinder.
Claim 5
Dependent Claim 41 words
A direct injection diesel engine as defined in claim 3, wherein the distance from the center of the piston pin to the top surface of the piston is set equal to thirty five percent of the bore diameter of the cylinder.
Claim 6
Dependent Claim 29 words
A direct injection diesel engine as defined in claim 1, wherein the squish suppressing mechanism comprises a variable swirl generator which sets up a swirl in the combustion chamber.
Claim 7
Dependent Claim 56 words
A direct injection diesel engine as defined in claim 1, wherein the squish suppressing mechanism comprises a cavity formed on a top surface of the piston, the cavity having a diameter larger than sixty percent of a bore diameter of the cylinder, and a depth smaller than fifteen percent of the bore diameter of the cylinder.
Claim 8
Dependent Claim 47 words
A direct injection diesel engine as defined in claim 6, wherein the diameter of the cavity is equal to seventy percent of the bore diameter of the cylinder, and the depth of the cavity is set equal to thirteen percent of the bore diameter of the cylinder.
Claim 9
Dependent Claim 32 words
A direct injection diesel engine as defined in claim 1, wherein the engine comprises an accumulator for supplying high-pressure fuel to the fuel injector, and the fuel injector comprises a solenoid valve.
Claim 10
Dependent Claim 45 words
A direct injection diesel engine as defined in claim 1, wherein the engine further comprises an intake valve for aspirating air to the combustion chamber, and a variable valve mechanism which increases the effective combustion ratio by delaying the closing timing of the intake valve.
Claim 11
Dependent Claim 56 words
A direct injection diesel engine as defined in claim 9, wherein the squish suppressing mechanism comprises a cavity formed on a top surface of the piston, the cavity having a diameter larger than seventy percent of a bore diameter of the cylinder, and a depth smaller than thirteen percent of the bore diameter of the cylinder.
Claim 12
Dependent Claim 22 words
A direct injection diesel engine as defined in claim 10, wherein the compression ratio of the engine is set equal to thirteen.
Claim 13
Independent Claim 145 words
A method for enabling low temperature premixture combustion in a direct injection diesel engine which directly injects fuel into a combustion chamber formed by a piston by means of a fuel injector, the method comprising: retarding a fuel injection timing of the fuel injector to a timing not before compression top dead center of the piston; determine a fuel injection amount of the fuel injector so that an injection of all of a required amount of fuel is completed within an ignition delay period; decreasing an oxygen concentration of the combustion chamber by mixing a part of exhaust gas discharged from the combustion chamber with an intake air of the combustion chamber; setting a compression ratio of the engine not greater than fifteen; suppressing a squish formed in the combustion chamber; and setting a maximum pressure in the combustion chamber not greater than twelve Megapascals.
Claim 14
Independent Claim 145 words
A method for enabling low temperature premixture combustion in a direct injection diesel engine which directly injects fuel into a combustion chamber formed by a piston by means of a fuel injector, the method comprising: retarding a fuel injection timing of the fuel injector to a timing not before compression top dead center of the piston; determine a fuel injection amount of the fuel injector so that an injection of all of a required amount of fuel is completed within an ignition delay period; decreasing an oxygen concentration of the combustion chamber by mixing a part of exhaust gas discharged from the combustion chamber with an intake air of the combustion chamber; setting a compression ratio of the engine not greater than fifteen; suppressing a squish formed in the combustion chamber; and setting a maximum pressure in the combustion chamber not greater than twelve Megapascals.
Claim 15
Dependent Claim 43 words
A method for enabling low temperature premixture combustion as defined in claim 12, wherein the method suppresses the squish by generating a swirl in the combustion chamber while maintaining a turbulence energy in the combustion chamber at not less than a predetermined value.

References Cited (Backward Citations)

US3786792A Cited
US4444166A Cited
US4429669A Cited
US4644926A Cited
US5201300A Cited
JPH074287A Cited
JPH0886251A Cited
JPH11107820A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2003-12-12 2004-06-12 2004-12-12 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2007-12-12 2008-06-12 2008-12-12 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2011-12-12 2012-06-12 2012-12-12 $7700.00 Window Closed / Lapsed

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