Patent US3868939A successfully refreshed from Google Patents.
US3868939A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fuel injection system especially for cold starting and warming up externally ignited internal combustion engines
Assignee: Robert Bosch GmbH
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Filing: 1973-03-02
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Granted: 1975-03-04
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Expires: 1993-03-02
Abstract
Abstract An improved fuel injection system in an internal combustion engine is described, wherein the system has a discharge outlet for fuel to be injected and brought to a combustion space of the engine, an electrical heating element for heating the fuel directly upstream of the discharge outlet, a fuel entry structure for feeding fuel to the heating element and temperature control structure for controlling the heating by the heating element, at engine temperatures below the optimal operational engine temperature and as a function of engine temperatures influencing the formation of the fuel-air mixture in the combustion space, the fuel being heated to such a degree that the preponderant portion of the amount of fuel to be injected is converted to the gaseous phase not later than immediately after leaving the discharge outlet, and wherein the improvement comprises an internal space in the system, adapted for the flow of fuel therethrough and extending from the fuel entry structure to the discharge outlet, which space is laid out for the smallest fuel volume possible, but in any event has a volume smaller than the volume of fuel injectable during about eight work cycles of the engine while the latter is idling.
Inventors
- 👤 Karl-Hermann Friese
- 👤 Friedbert Michel
- 👤 Rudolf Krauss
- 👤 Gunther Jaggle
- 👤 Gerhard Stumpp
- 👤 Josef Steiner
- 👤 Heinrich Knapp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 12:05
CPC Classifications
F; F02; F02M; F02M53/00; F02M53/04; F02M53/06; C; C09; C09J; C09J7/00; C09J7/10; F02M2700/00; F02M2700/07; F02M2700/077
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
199 words
In an internal combustion engine of the type having a combustion space and a fuel injection system comprising: a. a discharge outlet for fuel to be injected and brought to said combustion space; b. an electrical heating element for heating fuel to be injected, directly upstream of said discharge outlet; c. a fuel entry means for feeding fuel into said heating element; and d. temperature control means for controlling the heating of said fuel by said heating element, dependent on an engine temperature influencing the formation of a fuel/air mixture in said combustion space, said temperature control means causing the fuel to be heated, at temperatures below the optimal operational temperature of the engine, to such a degree that the preponderant portion of the amount of fuel to be injected is converted to the gaseous phase at the latest immediately after leaving said discharge outlet; the improvement of said injection system comprising further an internal space adapted for the flow of fuel therethrough and extending from said fuel entry means to said discharge outlet, said space having a volume smaller than the volUme of fuel injectable during about eight work cycles of said engine while the latter is idling.
Claim 2
Dependent Claim
199 words
In an internal combustion engine of the type having a combustion space and a fuel injection system comprising: a. a discharge outlet for fuel to be injected and brought to said combustion space; b. an electrical heating element for heating fuel to be injected, directly upstream of said discharge outlet; c. a fuel entry means for feeding fuel into said heating element; and d. temperature control means for controlling the heating of said fuel by said heating element, dependent on an engine temperature influencing the formation of a fuel/air mixture in said combustion space, said temperature control means causing the fuel to be heated, at temperatures below the optimal operational temperature of the engine, to such a degree that the preponderant portion of the amount of fuel to be injected is converted to the gaseous phase at the latest immediately after leaving said discharge outlet; the improvement of said injection system comprising further an internal space adapted for the flow of fuel therethrough and extending from said fuel entry means to said discharge outlet, said space having a volume smaller than the volUme of fuel injectable during about eight work cycles of said engine while the latter is idling.
Claim 3
Dependent Claim
76 words
The improvements as described in claim 1, wherein said injection system further comprises an injection valve housing, a valve needle, a return spring, a pressure chamber, and insulation means surrounding said heating element, said valve needle being adapted for opening in the direction of fuel flow under the pressure of the fuel supplied to said injection valve and against the force of said return spring, and said electrical heating element being located in said pressure chamber.
Claim 4
Dependent Claim
54 words
The improvement as described in claim 2, wherein said injection system comprises a plurality of passages for the flow of fuel therethrough all of which are laid out so that the loss of fuel pressure at maximum fuel throughout is at most 15 percent of the fuel pressure required to open said injection valve.
Claim 5
Dependent Claim
24 words
The improvement as described in claim 2, wherein said electrical heating element is adapted for direct contact with fuel flowing through said injection valve.
Claim 6
Dependent Claim
37 words
The improvement as described in claim 3, wherein said heating element comprises passages for fuel flow permitting transfer of heat from said heating element to the fuel and being laid out for maximum velocity of fuel flow.
Claim 7
Dependent Claim
21 words
The improvement as described in claim 4, wherein said electrical heating element is of sleeve shape and surrounds said valve needle.
Claim 8
Dependent Claim
47 words
The improvement as described in claim 5, wherein electrical heating element is of sleeve shape and said wherein a heat transfer body is arranged about said valve needle guiding the latter with play, said heat transfer body being in turn surrounded by said sleeve-shaped electrical heating element.
Claim 9
Dependent Claim
30 words
The improvement as described in claim 2, wherein said electrical heating element is removable from said pressure chamber and is arranged upstream of said valve needle in said valve housing.
Claim 10
Dependent Claim
16 words
The improvement as described in claim 2, wherein said electrical heating element is a heating coil.
Claim 11
Dependent Claim
26 words
The improvement as described in claim 2, wherein said electrical heating element comprises at least one carrier body coated with a layer of electric current-conducting material.
Claim 12
Dependent Claim
29 words
The improvement as described in claim 10, wherein the thickness of said layer on said carrier body increases in the direction of flow of fuel through said injection system.
Claim 13
Dependent Claim
18 words
The improvement as described in claim 6, wherein said electrical heating element comprises a number of capillary tubes.
Claim 14
Dependent Claim
19 words
The improvements as described in claim 6, wherein said electrical heating element has a number of narrow gaps therethrough.
Claim 15
Dependent Claim
17 words
The improvement as described in claim 6, wherein said electrical heating element consists of a whisker package.
Claim 16
Dependent Claim
38 words
The improvement as described in claim 2, wherein said injection valve housing has a passage of reduced diameter at the end of said electrical heating element toward said fuel entry means, said passage acting as a heat throttle.
Claim 17
Dependent Claim
43 words
The improvement as described in claim 6, wherein said electrical heating element comprises a current-carrying member consisting of PTC material, whereby the heat output of said heating element is made dependent of the change of resistivity of said PTC material with the temperature.
Claim 18
Dependent Claim
29 words
The improvement as described in claim 16, wherein said electrical heating element comprises a tube of PTC material having a Curie point below the cracking temperature of the fuel.
Claim 19
Dependent Claim
43 words
The improvement as described in claim 17, wherein said electrical heating element comprises two current-feeding contactor means arranged radially opposite one another, one on the outside surface and the other on the inside surface of the wall of said tube of cold-conductor material.
Claim 20
Dependent Claim
33 words
The improvement as described in claim 18, wherein the tube has a crimped rim at the end thereof toward said fuel entry means, and wherein said conductors are mounted on said crimped rim.
Claim 21
Dependent Claim
45 words
The improvement as described in claim 2, Wherein said injection system further comprises switch means whereby said electrical heating system can be switched on, firstly, when said internal combustion engine is rotating, and secondly, prior to starting said engine, in order to preheat the fuel.
Claim 22
Dependent Claim
57 words
The improvement as described in claim 20, wherein said fuel injection system further comprises a suction tube for aspirating air and measuring device for determining the flow of air through said suction tube, air flowing through said suction tube when said internal combustion engine is rotating and thus giving an impulse to switch on the heating system.
Claim 23
Dependent Claim
49 words
The improvement as described in claim 2, wherein said fuel injection system further comprises means for controlling the temperature of the fuel in said system and for maintaining such fuel temperature below the temperature of self-ignition even when very small quantities of fuel are being injected by said system.
References Cited (Backward Citations)
US1780499A
Cited
US2855908A
Cited
US3408007A
Cited
US3601110A
Cited
US3731876A
Cited
US3762378A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-03 | 1978-09-02 | 1979-03-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-03 | 1982-09-02 | 1983-03-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-03 | 1986-09-02 | 1987-03-04 | $7700.00 | Window Closed / Lapsed |