US3872850A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fuel injection systems
Assignee: ZF International UK Ltd
•
Filing: 1969-02-04
•
Granted: 1975-03-25
•
Expires: 1989-02-04
Abstract
Abstract A fuel injection system for an internal combustion engine comprising a pump, a fuel pressure operated metering and distributing unit, and at least one nozzle in the inlet manifold of the engine, a pressure relief means disposed between the pump and the metering and distributing unit and control means including an electrical solenoid for operating the pressure relief means, so that under certain engine operating conditions fuel reaches the metering and distributing unit at a pressure which is insufficient for delivery to the nozzle.
Inventors
- 👤 Herbert James Littlehales
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:20
CPC Classifications
F; F02; F02M; F02M63/00; F02M63/02
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
117 words
A fuel injection system having a pump, a metering unit, a pressure relief valve connected between the pump and the metering unit, said pressure relief valve having a first setting in which it can spill fuel delivered by the pump in excess of a predetermined pressure, and electrical control means associated with the pressure relief valve, and the pressure relief valve having a further setting which is selectable by actuation of the control means at selected engine operating conditions to reduce the pressure at which the pressure relief valve opens to a pressure below that at which the metering unit can deliver fuel to at least one nozzle disposed in the inlet manifold of the associated engine.
Claim 2
Dependent Claim
117 words
A fuel injection system having a pump, a metering unit, a pressure relief valve connected between the pump and the metering unit, said pressure relief valve having a first setting in which it can spill fuel delivered by the pump in excess of a predetermined pressure, and electrical control means associated with the pressure relief valve, and the pressure relief valve having a further setting which is selectable by actuation of the control means at selected engine operating conditions to reduce the pressure at which the pressure relief valve opens to a pressure below that at which the metering unit can deliver fuel to at least one nozzle disposed in the inlet manifold of the associated engine.
Claim 3
Dependent Claim
41 words
A fuel injection system as claimed in claim 1 in which the control means comprises an electrical solenoid to actuate the pressure relief valve, coNnected in an electrical circuit containing a switch which is operated when the selective operating conditions exist.
Claim 4
Dependent Claim
35 words
The fuel injection system as claimed in claim 2 in which one of the switches is connectable to an engine throttle and the other is operable in response to a manifold depression in the engine.
Claim 5
Dependent Claim
34 words
The fuel injection system as claimed in claim 3 in which the switches are arranged in series and both switches are closed to energize the solenoid only when the engine is on overrun conditions.
Claim 6
Dependent Claim
16 words
The fuel injection system as claimed in claim 3 in which the switches are in parallel.
References Cited (Backward Citations)
US2899951A
Cited
US2053543A
Cited
US2939444A
Cited
US2957463A
Cited
US2977944A
Cited
US3220392A
Cited
US3463130A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |