US4399786A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for pilot injection of fuel in diesel engines
Assignee: Volvo AB
•
Filing: 1980-08-25
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Granted: 1983-08-23
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Expires: 2000-08-25
Abstract
Abstract A method for the pilot injection of fuel in a direct injection diesel engine with a depression in the tops of the pistons. The pilot fuel, of relatively high cetane number, e.g. diesel fuel, is sprayed prior to the main spray, obliquely from the side into the piston depression in a direction counter to the rotation of the intake air. Thereafter, during the same combustion cycle, the main spray, of lower cetane number, e.g. methanol, is sprayed in a zone around the center axis of the piston depression. A substantial reduction in pollutants is achieved.
Inventors
- 👤 Heinz E. A. Holmer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:10
CPC Classifications
F; F02; F02M; F02M59/00; F02M59/02; F02M59/08; F02B; F02B23/00; F02B23/02; F02B23/06; F02B23/0645; F02B23/0663; F02B23/0696; F02B3/00; F02B3/06; F02M63/00; F02B2275/00; F02B2275/14; F02B23/0618; F02B23/0624; F02B23/0666; F02B23/0669; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
163 words
In a fuel injection method for direct injection diesel engines with a depression in the tops of the pistons, in which a first injection pump with a regulator and accompanying first injector for each cylinder sprays fuel with a relatively low cetane number in a main spray in a zone around the center axis of the respective piston depression; the improvement comprising injecting a pilot spray of a fuel with a relatively high cetane number from a second injection pump (6) with a regulator and accompanying second injectors (8) for each cylinder, from the side into the respective piston depression in a direction (B) toward a central zone in the piston depression in which the intake air rotates, operating both of said injection pumps during a combustion cycle, and injecting said pilot spray before said main spray so that the compression combustion of the fuel from the second injection pump (6) can initiate the combustion of the fuel from the first pump (1).
Claim 2
Dependent Claim
163 words
In a fuel injection method for direct injection diesel engines with a depression in the tops of the pistons, in which a first injection pump with a regulator and accompanying first injector for each cylinder sprays fuel with a relatively low cetane number in a main spray in a zone around the center axis of the respective piston depression; the improvement comprising injecting a pilot spray of a fuel with a relatively high cetane number from a second injection pump (6) with a regulator and accompanying second injectors (8) for each cylinder, from the side into the respective piston depression in a direction (B) toward a central zone in the piston depression in which the intake air rotates, operating both of said injection pumps during a combustion cycle, and injecting said pilot spray before said main spray so that the compression combustion of the fuel from the second injection pump (6) can initiate the combustion of the fuel from the first pump (1).
Claim 3
Dependent Claim
58 words
Injection method according to claim 1, in which each respective first injector (4) is disposed to inject the fuel with a large uniform distribution around the center axis (Z) of the piston depression, while each respective second injection (8) is disposed to inject the fuel with a small distribution obliquely from the side into the piston depression (A).
Claim 4
Dependent Claim
23 words
Injection method according to claim 1, in which the first injectors (4) have multi-hole nozzles, while the second injectors (8) have single-hole nozzles.
Claim 5
Dependent Claim
96 words
Injection method according to claim 1, in which each respective second injector (8) is disposed to inject the fuel from a location on or in the vicinity of the periphery of the piston depression (A) and with an injection path (B), which forms an angle (α) of between 10° and 20° with a cross-sectional plane through the cylinder and whose projection onto said plane is tangent to a circle concentric to the periphery of the piston depression, the radius (r) of said circle being between 0.35 and 0.45 times the radius (R) of the piston depression.
Claim 6
Dependent Claim
14 words
Injection method according to claim 4, in which said angle (α) is about 15°.
Claim 7
Dependent Claim
22 words
Injection method according to claim 4, in which said radius (r) is about 0.40 times the radius (R) of the piston depression.
Claim 8
Dependent Claim
42 words
Injection method according to claim 1, in which the second injection pump (6) is set to essentially only inject the required amount of fuel for starting, warming up and idling, the first injection pump (1) being inactive when the engine is idling.
Claim 9
Dependent Claim
33 words
Injection method according to claim 1, in which the first injection pump (1) is set to inject fuel at about 10 degrees of rotation of the crankshaft after the second injection pump (6).
Claim 10
Dependent Claim
18 words
Injection method according to claim 1, in which said fuel of relatively low cetane number is an alcohol.
Claim 11
Dependent Claim
12 words
Injection method according to claim 9, in which said alcohol is methanol.
Claim 12
Dependent Claim
36 words
Injection method according to claim 1, in which the pilot spray is injected obliquely from the side into the respective piston depression in a direction (B) which is counter to the rotation of the intake air.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-08-22 | 1987-02-21 | 1987-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-22 | 1991-02-21 | 1991-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-22 | 1995-02-21 | 1995-08-23 | $7700.00 | Window Closed / Lapsed |