GB2192225A - I.c. engine with fuel vaporisation - Google Patents

I.c. engine with fuel vaporisation Download PDF

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Publication number
GB2192225A
GB2192225A GB08616191A GB8616191A GB2192225A GB 2192225 A GB2192225 A GB 2192225A GB 08616191 A GB08616191 A GB 08616191A GB 8616191 A GB8616191 A GB 8616191A GB 2192225 A GB2192225 A GB 2192225A
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United Kingdom
Prior art keywords
fuel
engine
temperature
flame
cool
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08616191A
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GB2192225B (en
GB8616191D0 (en
Inventor
John H Greenhough
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Individual
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Individual
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Publication date
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Priority to GB8616191A priority Critical patent/GB2192225B/en
Publication of GB8616191D0 publication Critical patent/GB8616191D0/en
Publication of GB2192225A publication Critical patent/GB2192225A/en
Application granted granted Critical
Publication of GB2192225B publication Critical patent/GB2192225B/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B23/00—Other engines characterised by special shape or construction of combustion chambers to improve operation
    • F02B23/08—Other engines characterised by special shape or construction of combustion chambers to improve operation with positive ignition
    • F02B23/10—Other engines characterised by special shape or construction of combustion chambers to improve operation with positive ignition with separate admission of air and fuel into cylinder
    • F02B23/104—Other engines characterised by special shape or construction of combustion chambers to improve operation with positive ignition with separate admission of air and fuel into cylinder the injector being placed on a side position of the cylinder
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B75/00—Other engines
    • F02B75/12—Other methods of operation
    • F02B2075/125—Direct injection in the combustion chamber for spark ignition engines, i.e. not in pre-combustion chamber
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Abstract

At least part of a charge of fuel is introduced by means of an injector 11, 11a and caused to impinge, as a liquid, upon a hot surface such as an exhaust valve 12 or a part of the cylinder head 14 or of the piston 16 at a temperature which is sufficiently high to cause the fuel to heat-up rapidly through its cool-flame combustion range without significant formation of cool flame by-products, and at a pressure which is at or near atmospheric. <IMAGE>

Description

SPECIFICATION Internal combustion engine This invention relates to an internal combustion engine.
When hydro-carbon fuels are mixed with air and subjected to heat in the induction and compression stage of the engine, there is a complex chemical chain reaction. With most fuels there exists a two stage reaction mechanism, one a low temperature oxidation and the other a high temperature oxidation. The low temperature pre-flame reaction is more predominant up to cool flame threshold temperature which varies from fuel to fuel, but is about in the range 250 -3500C and is dependent on chain branch processes, which involve the formation of aldehydes and peroxides and partial ignition (cool flame). The cool flame threshold cannot be specified in relation to all fuels, but for any individual fuel it can be ascertained very easily.
As the temperature increases beyond this threshold there is a decrease in the reaction of the fuel until a higher temperature mechanism becomes effective and reaction increases again followed by auto-ignition.
The composition and concentration of gases generated by pre-flame and cool flame reaction, are known under certain engine conditions to cause rapid and violent ignition (knock).
This has led to the selection of fuels and additives (iso-octane and lead etc.) which have a resistance to pre-flame reaction and cool flame, so that engine efficiency can be improved.
In general fuels that readily oxidize for example N Heptane have a-high pre-flame and cool flame reaction, and rapidly auto-idnite and knock readily.
Benzine is difficult to oxidize and it does not produce cool flame and is relatively slow to auto-ignite and knock.
Iso-octane has a resistance to oxidation and pre-flame reaction and a good resistance to knock.
Easily oxidized fuels are low octane fuels and fuels with high resistance to oxidation are high octane fuels. In effect the octane number of a fuel is a measurement of its resistance to oxidation and pre-flame and cool flame reaction.
The hydro-carbons prone to knock readily form aldehyde and peroxides while hydro-carbons like Benzines do not and are highly resistant to knock.
It is know that aldehydes and organic peroxides are formed in the first stage of low temperature oxidation and cause cool flame reaction which leads to engine knock.
It is an object of the present invention to provide an internal combustion engine wherein this undesirable reaction can be overcome so that unleaded low grade fuel can be used without impairing engine efficiency.
The invention provides an internal combustion engine wherein at least a fraction of a change of a hydrocarbon liquid fuel is impinged upon a surface whose temperature is sufficient to rapidly raise the temperature of the fuel above its cool-flame threshold temperature (as hereinafter defined) and at a pressure at or close to atmospheric pressure.
The 'cool flame threshold' temperature is best defined by referring to the ignition and combustion characteristics of a liquid hydrocarbon fuel. At lower temperatures, say from 150"C up to a threshold, hydrocarbon fuels undergo chemical breakdown without burning (so-called "cool flame") to form aldehyde and other products. These products are easily raised to full ignition conditions but heat and pressure and they ignite easily. This leads often to pre-ignition well before TDC and to the familiar and undesirable characteristic of "pinking" or "knock". The fuel also has its own ignition point at which it will ignite and burn by means of a spark or other ignition. What has not always been appreciated, however, is that most (if not all) liquid hydrocarbon fuels have a cool flame threshold temperature.
Above this temperature the fuel is relatively stable and does not undergo the "cool flame" type deterioration reactions which generate aldehydes, peroxides and similar troublesome pre-ignition chemical products. between the cool flame threshold and the ignition temperatures the fuel is relatively stable.
The surface is preferably above 300"C. The time of vaporization at this temperature can be one seventieth of the time required for the same fuel to be vaporized when injected into air at the same temperature.
By impinging liquid fuel on the hot surface that is maintained at the high temperature the fuel passes so quickly through the temperature zone in which aldehydes and organic peroxides are formed that no appreciable amounts of these products are generated.
The invention will be described further, by way of example, with reference to the accompanying drawings wherein, the single figure is a cross-sectional view through a preferred engine of the invention.
The combustion engine 10 of the invention is representative only of a number of engines which can embody this invention wherein at least a fraction of each fuel change is preinjected at or about atmospheric pressure, i.e.
before significant pressure build up in the engine, using an injector 11 to impinge on a hot exhaust valve 12 closing exhaust duct 13 in cylinder head 14, closing of piston 15 with cylinder 16. Alternatively an injector 11a can inject to impinge upon an area of the cylinder head hot enough to cause the desired heating, i.e. close to the exhaust valve. Other parts of the engine may be hot enough, such as the inlet manifold or the cylinder, or the piston crown, and have enough heat capacity to take the fuel injection. The surface temperature needed is above the actual fuel's cool flame threshold to ensure a rapid fuel temperature rise above its cool flame threshold.Further, the surface used should be a surface of a body, usually of metal, which has a relatively high thermal capacity and good conductivity so that a stream of cool flame fuel onto the surface cannot appreciably cool it.
The surface should be at least 25"C above the fuel's threshold temperature and preferably 50"C above it. A typical fuel like diesel oil has a cool flame threshold temperature of about 250 C and thus a convenient practical lower limit for the surface temperature used should be 300"C.
It is important to note that in my prior patent application No.UK 2163486A I have disclosed the idea of injecting onto a hot surface ( > 300 C) within a cylinder head whilst the piston is at or near TDC, i.e. when the pressure in the cylinder is raised substantially above atmospheric pressure. However, the step of injecting during induction when pressures are low leads to considerable advance in the two stage fuel introduction engine which is disclosed in my prior application No.UK 2169960A (to be published 23rd July 1986).

Claims (7)

1. An internal combustion engine wherein at least a fraction of a charge of a hydrocarbon liquid fuel is impinged upon a surface whose temperature is sufficient to rapidly raise the temperature of the fuel above its cool-flame threshold temperature (as hereinbefore defined) and at a pressure at or close to atmospheric pressure.
2. An engine as claimed in claim 1 wherein the temperature of the surface is above 300"C.
3. An engine as claimed in claim 1 or 2 wherein the temperature of the surface is at least 25"C above the fuel's threshold temperature.
4. An engine as claimed in claim 3 wherein the temperature of the surface is at least 50"C above the fuel's threshold temperature.
5. An engine as claimed in any preceding claim wherein the fuel is impinged upon an exhaust valve, an area of the cylinder head or the piston crown which is of metal and has high thermal capacity.
6. An engine as claimed in any preceding claim, wherein the fuel is injected during an induction stroke of the engine.
7. An internal combustion engine substantially as hereinbefore described with reference to the accompanying drawings.
GB8616191A 1986-07-02 1986-07-02 Method of operating an internal combustion engine Expired - Lifetime GB2192225B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8616191A GB2192225B (en) 1986-07-02 1986-07-02 Method of operating an internal combustion engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8616191A GB2192225B (en) 1986-07-02 1986-07-02 Method of operating an internal combustion engine

Publications (3)

Publication Number Publication Date
GB8616191D0 GB8616191D0 (en) 1986-08-06
GB2192225A true GB2192225A (en) 1988-01-06
GB2192225B GB2192225B (en) 1990-01-17

Family

ID=10600484

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8616191A Expired - Lifetime GB2192225B (en) 1986-07-02 1986-07-02 Method of operating an internal combustion engine

Country Status (1)

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GB (1) GB2192225B (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB694457A (en) * 1951-01-08 1953-07-22 Sing Nam Chan Improvements in or relating to apparatus for cracking oils for supply of oil gas to internal combustion engines
GB916230A (en) * 1959-09-15 1963-01-23 Inst Francais Du Petrole Improvements in or relating to compression ignition engines
US3824965A (en) * 1972-01-20 1974-07-23 Thermo Electron Corp Fuel system
GB1423695A (en) * 1972-08-05 1976-02-04 Daimler Benz Ag Method and apparatus for the exhaust-gas emission of internal combustion engines
GB2133468A (en) * 1983-01-10 1984-07-25 Ford Motor Co Method of direct injection of high heat of vaporisation fuel, e.g. methanol

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8500270D0 (en) * 1985-01-05 1985-02-13 Greenhough J H Four stroke i c engine
DE3771942D1 (en) * 1986-06-19 1991-09-12 Nippon Clean Engine Res INTERNAL COMBUSTION ENGINE WITH FUEL INJECTION.

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB694457A (en) * 1951-01-08 1953-07-22 Sing Nam Chan Improvements in or relating to apparatus for cracking oils for supply of oil gas to internal combustion engines
GB916230A (en) * 1959-09-15 1963-01-23 Inst Francais Du Petrole Improvements in or relating to compression ignition engines
US3824965A (en) * 1972-01-20 1974-07-23 Thermo Electron Corp Fuel system
GB1423695A (en) * 1972-08-05 1976-02-04 Daimler Benz Ag Method and apparatus for the exhaust-gas emission of internal combustion engines
GB2133468A (en) * 1983-01-10 1984-07-25 Ford Motor Co Method of direct injection of high heat of vaporisation fuel, e.g. methanol

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
WO A1 86/04111 *

Also Published As

Publication number Publication date
GB2192225B (en) 1990-01-17
GB8616191D0 (en) 1986-08-06

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PCNP Patent ceased through non-payment of renewal fee

Effective date: 19980702