CA1203132A - Duel fuel system for compression ignition engine - Google Patents
Duel fuel system for compression ignition engineInfo
- Publication number
- CA1203132A CA1203132A CA000405749A CA405749A CA1203132A CA 1203132 A CA1203132 A CA 1203132A CA 000405749 A CA000405749 A CA 000405749A CA 405749 A CA405749 A CA 405749A CA 1203132 A CA1203132 A CA 1203132A
- Authority
- CA
- Canada
- Prior art keywords
- engine
- hydraulic pressure
- fuel feed
- gaseous fuel
- engine speed
- 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.)
- Expired
Links
Classifications
-
- 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
- Y02T10/30—Use of alternative fuels, e.g. biofuels
Landscapes
- Output Control And Ontrol Of Special Type Engine (AREA)
Abstract
ABSTRACT
A compression ignition engine having a pilot fuel feed to the engine and a separate gaseous fuel feed characterized in that the separate gaseous fuel feed is controlled by means controlled by hydraulic pressure dependent on engine speed and/or engine load.
A feature of importance is that for each engine speed when the engine is running the hydraulic pressure has a pre-determined maximum value, there being bleeding off circuitory or other means to enable reductions of hydraulic pressure below said maximum value for each speed. With such a means it is possible under low load conditions for engine speed governor means to cause the bleeding off circuitory or other means to cause a reduction in hydraulic pressure and hence gaseous fuel feed to engine at the particular engine speed.
Such a compression engine retrofitted or otherwise to pro-vide the features of the present invention has application with both standing and mobile action.
A compression ignition engine having a pilot fuel feed to the engine and a separate gaseous fuel feed characterized in that the separate gaseous fuel feed is controlled by means controlled by hydraulic pressure dependent on engine speed and/or engine load.
A feature of importance is that for each engine speed when the engine is running the hydraulic pressure has a pre-determined maximum value, there being bleeding off circuitory or other means to enable reductions of hydraulic pressure below said maximum value for each speed. With such a means it is possible under low load conditions for engine speed governor means to cause the bleeding off circuitory or other means to cause a reduction in hydraulic pressure and hence gaseous fuel feed to engine at the particular engine speed.
Such a compression engine retrofitted or otherwise to pro-vide the features of the present invention has application with both standing and mobile action.
Description
A COMPRESSION IGNI~ION ENGINE
1 This invention relates to a system o gas fuelling of compression ignition engines preferably of the high-speed type. These engines would predominantly be in automotive applications fuelled by CNG and diesel.
The proble~ this invention aims to overcome is -to pro-vide a way of controlling the gas and diesel fuelling of engines, when operating in a dual fuel mode, in such a way as to provide satisfactory and efficient operation of these engines. A secondary problem the invention aims to overcome is that of being able to retrofit the control system to existing engines.
An object of the invention is to provide a means of gas fuelling which contains the desirable features of retention of the volumetric and thermodynamic efficiency of the engine coupled with the simplicity of design and maintenance of manifold admission of the gas fuel.
In addition, the related problem of control of detona-tion in the gas fuelled engine is provided for by wide variation of the air to gas ratio.
A further object is to provide a system that is basi.-cally fail-safe~ Some of the benefits of satisfying this requirement should permit compliance with CNG vehicle instaIlation regulations without the use o ancillary equipment.
Accordingly the present invention consists in a -~ ~ L~
~ compression ignition engine having a pilot\fuel feed to the 03~
1 engine and a separate gaseous fuel Eeed characteri~ed in that the separate gaseous fuel feed is controlled by means controlled by hydraulic pressure dependent on engine speed and/or engine load.
Preferably said means controlling said separate gaseous fuel feed is a valve.
Preferably said valve is a piston type valve.
PrefeL~bly said valve is a diaphragm type valve.
Preferably for each engine speed when the engine is 0 running the 'nydraulic pressure has a redetermined maximum C ~
.value there being bleeding off cir_~it~ to enable reduc-tions of hydraulic pressure below said maximum value for each engine speed.
Preferably means is provided whereby under low load con-ditions engine speed governor means cause the bleeding offc~c~
-C'__~iL~y~tO cause a reduction in hydraulic pressure and hence gaseous fuel feed for the particular engine speed.
Preferably said hydraulic pressure is dependant on engine speed and the means which controls the separate gaseous fuel feed is a regulator valve dependant on such hydraulic pressure, said regulator valve and the hydraulic pressure being arranged such that there is no flow of said separate gaseous fuel feea when the engine is not running.
In a further aspect the invention consists in a compression ignition engine of a kind having a pilot liquid fuel feed into each combustion chamber and having a gaseous fuel feed to each combustion chamber characterized in that there is provided:
1 means clependant on gngine speed to generate a hydraulic pressure which increases with engine speed~
means to govern the effect of load on any engine speed, means responsive to said means to govern to reduce said hydraulic pressu.re in low load situations t~ result in a resultant hydrau.lic pressure less that otherwise would be the case, and means dependant on said resultant hydraulic pressure to.control the feed of said gaseous fuel, the arrangement being such that when the engine is not running said means dependant on said resultant hydraulic pressure does not allow a gaseous fuel feed and such that for each speed there is a feed rate of gaseous fuel dependant on said resultant hydraulic pressure, the greatest gaseous feed or each ~5 engine speed being that when the engine is under load sufficient to minimize the reduction of said hyd.raulic pressure by said means responsive to said means to govern.
.. Preferably said means to govern is a mechanical governor, or hydraulic governor, the mechanical movement of which is constrained from adjusting the liquid fuel feed and instead arranged to coact with said means responsive to said means to govern.
Preferably said gaseous feed is into the inlet manifold or manifolds of the engine.
~5 Preferably saîd means responsive to said means to govern is a bleeding circuit.
In yet a ~urther aspect the present invention consists . .
203~3;Z
1 in a fuel system for a compression ignition engine which results in a compression ignition engine in accordance with the present invention. The presen-t invention also consists in componentry for retrofitting~a compression ignition engine (preferably a governed compression ignition engine) to provide a compression ignition engine in accordance with the present invention.
Preferred forms of the present invention will now be described with reference to the accompanying drawings in which:
Figure 1 is a flow diagram showing part of the com-ponentry in accordance with the present invention, T designating a diesel or other liquid fuel tank, P designating a fuel pump, V designating a change over valve, G designating a governor , G.F. designating a gaseous fuel supply, R designating a regulator which is the prefexred form of valve in accordance with the present invention, and E designates the engine and preferably the engine manifold to receive the gaseous fuel flow, components P and R being shown diagrammatically in section, Figure 2 is a diagrammatic view of a hydraulic governor having the accelerator linkage designated as A and the flow into the governor being designated by an arrow, the flow out from the governor being designated by an arrow and the two~
way flow also designated by arrow between the governor and -- 4 ~
~ 2~ L3~
1 the regulator e.g, R of Figure 1, Figure 3 is a governor valve se~sing mechanical movement of the engines centrifugal governor to provide the bleeding wanted in low load situations again with the arrows designating the same features and Figure 4 shows an alternative governor valve to that of Figure 3, again sensing mechanical movement of the engine's centrifugal governor to provide the bleeding wanted in low load situations, again with the arrows designating the same features~
In a preferred form the present.invention cons.ists in a compression ignition engine of a kind having a pilot liquid fuel eed into each combustion.chamber and having a gaseous fuel feed to each combustion chamber characterized in that there is provided:
means dependent on engine speed to generate a hydraulic pressure which increases with engine speed, means to govern the effect of load on any engine speed, means responsive to said means to govern to reduce said hydraulic pressure in low load situations to result in a resultant hydraulic pressure less that otherwise would be the case, and means dependent on said resultant hydraulic pressure to control the feed of said gaseous fuel, the arrangement being such that when the engine is not running said means dependent on said resultant hydraulic pressure does not allow a gaseous fuel feed and such that for each speed ~3~3Z
.. ~
1 there is a feed rate of gaseous fuel dependent on said resultant hydraulic pressure, the greatest gaseous feed for each engine speed being that when the engine is under load sufficient to ~ln;m; ze the reduction of said hydraulic pressure by said means responsive to said means to govern.
More broadly however the invention consists in a compression ignition engine having a pilot liquid fuel feed to the engine and a separate gaseous fuel feed characterized in that the separate gaseous fuel feed is controlled by means controlled by hydraulic pressure depend~ent on engine speed and/or engine load.
The invention also consists of apparatus for providing such fèed(s) and/or control and various conversion methods.
The basic operation of the invention can now be described. Gas flow to the inlet manifold of an engine possessing duel fuel capability is metered by hydraulic servo-control of a gas pressure regulator. Hydraulic fluid, which may be a fuel such as diesel, is admitted to one side of the regula~or diaphragm to balance gas pressure on the other side. Gas flow is therefore primarily regulated by the hydraulic fluid circuit although final adjus~ment of gas flow is by an adjustable metering orifice.
In a preferred embodiment of this invention, shown in Fig. 1, the hydraulic pump is a fuel injection pump used in diesel engines, and the hydraulic regulating fluid is diesel fuel. The hydraulic regulating pressure may then be tapped directly from the engine fuel injection line.
~3~3~
~d -1 For variable speed engines the system is described as ollows. A fixed displacement hydraulic pump such as the fuel injection pump described above, driven by the engine, in combination with a bleed orifice produces an output pressure related to engine speed. For certain rotary fuel injection pumps as fitted to these engines this variable pressure may be tapped directly from its trans~er pump. This output is led via a valve, the purpose of which is to change over from operation on diesel or single fuel to gas/pilot liquid fuel operation and thence via a governor valve for speed control of the engine to one side of the pressure regulating valve. Gas pressure produced in the regulator is thus in balance with the pressure output of the fuel injection or hydraulic fluid pump unless the governor valve is shut and is therefore related to the engine speed. By virtue of the pressure related flow characteristics through the gas metering orifice m~;rllm gas fuel to the engine at any given speed is determined for control of combustion chamber detonation.
Under engine acceleration conditions restrictive damping of the hydraulic line between the governor assembly and the regulator may be used to control combustion chamber detonation. Figure 1 of the accompanying drawings out line the system in the manner of a flow chart.
For constant speed engines the control system is able to be constructed more simply by connecting the governor valve to the engine lubrication oil pressure supply. The system as described above can then be adjusted , ..~, .. .
. `~ ; J
~2~3~
1 give the appropriate gas fuelling for the oil pressure available. A restrictor orifice ensures a minimum bleediny off of the lubrication oil.
For engines consuming gas from a flow pressure supply, normally constant speed engines fuelled by pro-ducer gas or biomass digestor gas of suitable calorific value, the control system is described as follows. A
constant pressure oil supply is used as noted above. A
changeover valve and governor valve are incorporated.
A pressurising fan is required to yield a positive pressure at the regulator valve. The pressure regulating valve is of a diferent type and would comprise either a large bore regulator valve as diagrammed or a butterfly yalve in the gas admission pipe under hydraulic control.
With reference to the operation of the governor and the pilot fuel control two systems are used.
Firstly a system has been devised in which the existing engine fuel control mechanism is restrained in the pilot fuel position mechanically, or by use`of a solenoid or a small pressure-operated ram and the existing engine governor is not used for speed control. The speed related output pressure of the system pump is used in a hydraulic governor valve one form o~ which is shown in Figure 2. ~Iere hydraulic pressure moves a control piston against spring pressure determined by the accelerator posi-tion to produce a reduced pressure in the static line between the governor valv~ and the gas pressure ~egulator.
,~, 3~3~
\
1 'rhat reduced pressure is related to the demand require-ments for engine speed.
Secondly a system has been devised in which the speed related hydraulic pressure of the pump is only used to control maximum fuelling of the engine and governing is obtained by the action of the engine's own centrifugal governor or hydraulic governor with a mechanical movement on a small hydraulic valve. Restraint of the engine's fuel control rack or equ~valent is obtained by action of a small hydraulic piston-two forms of which are shown in Figures 3 and 4~ These have a shut-down piston and governing valve combined into one unit. Admission of hydraulic pressure by the changeaver valve causes the piston to move forcing the control rack to move to the pilot fuel position which may be variable according to engine speed as determined by a stiff spring. Movement of the piston to the pilot fuel position uncovers a port admitting governor control pressure`to the static line between the governor valve ~nd the gas pressure regulatox. The movement of the engine's fuel control rack to operate the governor valve is con-fined to a small range about the pilot fuel position. On some engines on which heavy overload cannot be sustained on gas provision is made for the fuel control rack orce to overcome the force on the piston which returns the engine to diesel operation until the load reduces.
For constant speed engines a pressure as set or that engine can be used rather than a speed related hydraulic pressure as noted aboveO The descriptions of the operation g _ ,~. ~.. .
3~
1 of the governor and the pilot fuel control in both systems is unchanged however.
On the basis of the foregoing the many advantages of the present invention can readily be seen, for example, it can be seen that by using a small diesel or other liquid fuel pilot feed CNG or other combustible gas can be effectively employed in a wide range of engine usages without the draw-backs of most pre-existant systems. Also it can be seen that the choice of a higher than usual gas delivery pressure would permit a number of advantages including:-(i~ small bore plumbing with overall size reductions, ~ small physical size of the gas regulator allowing precise control, ~iii) remoteness of the gas regulator from the manifold, (iv) with high flows gas expansion is less so cooling effects are reduced.
It can also be seen that the use of hydraulic con-txol circuitry reduces the need for engine model specific parts in control linkages.
It can also be seen that the use of control within the hydraulic circuit itself yields the following benefits:-(i~ the need is obviated for low friction gas tight seals, ~3~3;2 1 (i.i) any failure or loss of control pressure makes the system failsafe.
It can also be seen that the provision for control of the amount of pilot fuel permits:-- (i) the governor to allow the engine to lapse back onto diesel under heavy overload, (ii) variation of pilot injection with engine speed particularly to compensate for variations of injection pump efficiency at different speeds.
It is believed therefore that the present invention in the form as~claimed or the more preferred form hereinbefore described should find wide spread acceptance.
~ 11 --<
1 This invention relates to a system o gas fuelling of compression ignition engines preferably of the high-speed type. These engines would predominantly be in automotive applications fuelled by CNG and diesel.
The proble~ this invention aims to overcome is -to pro-vide a way of controlling the gas and diesel fuelling of engines, when operating in a dual fuel mode, in such a way as to provide satisfactory and efficient operation of these engines. A secondary problem the invention aims to overcome is that of being able to retrofit the control system to existing engines.
An object of the invention is to provide a means of gas fuelling which contains the desirable features of retention of the volumetric and thermodynamic efficiency of the engine coupled with the simplicity of design and maintenance of manifold admission of the gas fuel.
In addition, the related problem of control of detona-tion in the gas fuelled engine is provided for by wide variation of the air to gas ratio.
A further object is to provide a system that is basi.-cally fail-safe~ Some of the benefits of satisfying this requirement should permit compliance with CNG vehicle instaIlation regulations without the use o ancillary equipment.
Accordingly the present invention consists in a -~ ~ L~
~ compression ignition engine having a pilot\fuel feed to the 03~
1 engine and a separate gaseous fuel Eeed characteri~ed in that the separate gaseous fuel feed is controlled by means controlled by hydraulic pressure dependent on engine speed and/or engine load.
Preferably said means controlling said separate gaseous fuel feed is a valve.
Preferably said valve is a piston type valve.
PrefeL~bly said valve is a diaphragm type valve.
Preferably for each engine speed when the engine is 0 running the 'nydraulic pressure has a redetermined maximum C ~
.value there being bleeding off cir_~it~ to enable reduc-tions of hydraulic pressure below said maximum value for each engine speed.
Preferably means is provided whereby under low load con-ditions engine speed governor means cause the bleeding offc~c~
-C'__~iL~y~tO cause a reduction in hydraulic pressure and hence gaseous fuel feed for the particular engine speed.
Preferably said hydraulic pressure is dependant on engine speed and the means which controls the separate gaseous fuel feed is a regulator valve dependant on such hydraulic pressure, said regulator valve and the hydraulic pressure being arranged such that there is no flow of said separate gaseous fuel feea when the engine is not running.
In a further aspect the invention consists in a compression ignition engine of a kind having a pilot liquid fuel feed into each combustion chamber and having a gaseous fuel feed to each combustion chamber characterized in that there is provided:
1 means clependant on gngine speed to generate a hydraulic pressure which increases with engine speed~
means to govern the effect of load on any engine speed, means responsive to said means to govern to reduce said hydraulic pressu.re in low load situations t~ result in a resultant hydrau.lic pressure less that otherwise would be the case, and means dependant on said resultant hydraulic pressure to.control the feed of said gaseous fuel, the arrangement being such that when the engine is not running said means dependant on said resultant hydraulic pressure does not allow a gaseous fuel feed and such that for each speed there is a feed rate of gaseous fuel dependant on said resultant hydraulic pressure, the greatest gaseous feed or each ~5 engine speed being that when the engine is under load sufficient to minimize the reduction of said hyd.raulic pressure by said means responsive to said means to govern.
.. Preferably said means to govern is a mechanical governor, or hydraulic governor, the mechanical movement of which is constrained from adjusting the liquid fuel feed and instead arranged to coact with said means responsive to said means to govern.
Preferably said gaseous feed is into the inlet manifold or manifolds of the engine.
~5 Preferably saîd means responsive to said means to govern is a bleeding circuit.
In yet a ~urther aspect the present invention consists . .
203~3;Z
1 in a fuel system for a compression ignition engine which results in a compression ignition engine in accordance with the present invention. The presen-t invention also consists in componentry for retrofitting~a compression ignition engine (preferably a governed compression ignition engine) to provide a compression ignition engine in accordance with the present invention.
Preferred forms of the present invention will now be described with reference to the accompanying drawings in which:
Figure 1 is a flow diagram showing part of the com-ponentry in accordance with the present invention, T designating a diesel or other liquid fuel tank, P designating a fuel pump, V designating a change over valve, G designating a governor , G.F. designating a gaseous fuel supply, R designating a regulator which is the prefexred form of valve in accordance with the present invention, and E designates the engine and preferably the engine manifold to receive the gaseous fuel flow, components P and R being shown diagrammatically in section, Figure 2 is a diagrammatic view of a hydraulic governor having the accelerator linkage designated as A and the flow into the governor being designated by an arrow, the flow out from the governor being designated by an arrow and the two~
way flow also designated by arrow between the governor and -- 4 ~
~ 2~ L3~
1 the regulator e.g, R of Figure 1, Figure 3 is a governor valve se~sing mechanical movement of the engines centrifugal governor to provide the bleeding wanted in low load situations again with the arrows designating the same features and Figure 4 shows an alternative governor valve to that of Figure 3, again sensing mechanical movement of the engine's centrifugal governor to provide the bleeding wanted in low load situations, again with the arrows designating the same features~
In a preferred form the present.invention cons.ists in a compression ignition engine of a kind having a pilot liquid fuel eed into each combustion.chamber and having a gaseous fuel feed to each combustion chamber characterized in that there is provided:
means dependent on engine speed to generate a hydraulic pressure which increases with engine speed, means to govern the effect of load on any engine speed, means responsive to said means to govern to reduce said hydraulic pressure in low load situations to result in a resultant hydraulic pressure less that otherwise would be the case, and means dependent on said resultant hydraulic pressure to control the feed of said gaseous fuel, the arrangement being such that when the engine is not running said means dependent on said resultant hydraulic pressure does not allow a gaseous fuel feed and such that for each speed ~3~3Z
.. ~
1 there is a feed rate of gaseous fuel dependent on said resultant hydraulic pressure, the greatest gaseous feed for each engine speed being that when the engine is under load sufficient to ~ln;m; ze the reduction of said hydraulic pressure by said means responsive to said means to govern.
More broadly however the invention consists in a compression ignition engine having a pilot liquid fuel feed to the engine and a separate gaseous fuel feed characterized in that the separate gaseous fuel feed is controlled by means controlled by hydraulic pressure depend~ent on engine speed and/or engine load.
The invention also consists of apparatus for providing such fèed(s) and/or control and various conversion methods.
The basic operation of the invention can now be described. Gas flow to the inlet manifold of an engine possessing duel fuel capability is metered by hydraulic servo-control of a gas pressure regulator. Hydraulic fluid, which may be a fuel such as diesel, is admitted to one side of the regula~or diaphragm to balance gas pressure on the other side. Gas flow is therefore primarily regulated by the hydraulic fluid circuit although final adjus~ment of gas flow is by an adjustable metering orifice.
In a preferred embodiment of this invention, shown in Fig. 1, the hydraulic pump is a fuel injection pump used in diesel engines, and the hydraulic regulating fluid is diesel fuel. The hydraulic regulating pressure may then be tapped directly from the engine fuel injection line.
~3~3~
~d -1 For variable speed engines the system is described as ollows. A fixed displacement hydraulic pump such as the fuel injection pump described above, driven by the engine, in combination with a bleed orifice produces an output pressure related to engine speed. For certain rotary fuel injection pumps as fitted to these engines this variable pressure may be tapped directly from its trans~er pump. This output is led via a valve, the purpose of which is to change over from operation on diesel or single fuel to gas/pilot liquid fuel operation and thence via a governor valve for speed control of the engine to one side of the pressure regulating valve. Gas pressure produced in the regulator is thus in balance with the pressure output of the fuel injection or hydraulic fluid pump unless the governor valve is shut and is therefore related to the engine speed. By virtue of the pressure related flow characteristics through the gas metering orifice m~;rllm gas fuel to the engine at any given speed is determined for control of combustion chamber detonation.
Under engine acceleration conditions restrictive damping of the hydraulic line between the governor assembly and the regulator may be used to control combustion chamber detonation. Figure 1 of the accompanying drawings out line the system in the manner of a flow chart.
For constant speed engines the control system is able to be constructed more simply by connecting the governor valve to the engine lubrication oil pressure supply. The system as described above can then be adjusted , ..~, .. .
. `~ ; J
~2~3~
1 give the appropriate gas fuelling for the oil pressure available. A restrictor orifice ensures a minimum bleediny off of the lubrication oil.
For engines consuming gas from a flow pressure supply, normally constant speed engines fuelled by pro-ducer gas or biomass digestor gas of suitable calorific value, the control system is described as follows. A
constant pressure oil supply is used as noted above. A
changeover valve and governor valve are incorporated.
A pressurising fan is required to yield a positive pressure at the regulator valve. The pressure regulating valve is of a diferent type and would comprise either a large bore regulator valve as diagrammed or a butterfly yalve in the gas admission pipe under hydraulic control.
With reference to the operation of the governor and the pilot fuel control two systems are used.
Firstly a system has been devised in which the existing engine fuel control mechanism is restrained in the pilot fuel position mechanically, or by use`of a solenoid or a small pressure-operated ram and the existing engine governor is not used for speed control. The speed related output pressure of the system pump is used in a hydraulic governor valve one form o~ which is shown in Figure 2. ~Iere hydraulic pressure moves a control piston against spring pressure determined by the accelerator posi-tion to produce a reduced pressure in the static line between the governor valv~ and the gas pressure ~egulator.
,~, 3~3~
\
1 'rhat reduced pressure is related to the demand require-ments for engine speed.
Secondly a system has been devised in which the speed related hydraulic pressure of the pump is only used to control maximum fuelling of the engine and governing is obtained by the action of the engine's own centrifugal governor or hydraulic governor with a mechanical movement on a small hydraulic valve. Restraint of the engine's fuel control rack or equ~valent is obtained by action of a small hydraulic piston-two forms of which are shown in Figures 3 and 4~ These have a shut-down piston and governing valve combined into one unit. Admission of hydraulic pressure by the changeaver valve causes the piston to move forcing the control rack to move to the pilot fuel position which may be variable according to engine speed as determined by a stiff spring. Movement of the piston to the pilot fuel position uncovers a port admitting governor control pressure`to the static line between the governor valve ~nd the gas pressure regulatox. The movement of the engine's fuel control rack to operate the governor valve is con-fined to a small range about the pilot fuel position. On some engines on which heavy overload cannot be sustained on gas provision is made for the fuel control rack orce to overcome the force on the piston which returns the engine to diesel operation until the load reduces.
For constant speed engines a pressure as set or that engine can be used rather than a speed related hydraulic pressure as noted aboveO The descriptions of the operation g _ ,~. ~.. .
3~
1 of the governor and the pilot fuel control in both systems is unchanged however.
On the basis of the foregoing the many advantages of the present invention can readily be seen, for example, it can be seen that by using a small diesel or other liquid fuel pilot feed CNG or other combustible gas can be effectively employed in a wide range of engine usages without the draw-backs of most pre-existant systems. Also it can be seen that the choice of a higher than usual gas delivery pressure would permit a number of advantages including:-(i~ small bore plumbing with overall size reductions, ~ small physical size of the gas regulator allowing precise control, ~iii) remoteness of the gas regulator from the manifold, (iv) with high flows gas expansion is less so cooling effects are reduced.
It can also be seen that the use of hydraulic con-txol circuitry reduces the need for engine model specific parts in control linkages.
It can also be seen that the use of control within the hydraulic circuit itself yields the following benefits:-(i~ the need is obviated for low friction gas tight seals, ~3~3;2 1 (i.i) any failure or loss of control pressure makes the system failsafe.
It can also be seen that the provision for control of the amount of pilot fuel permits:-- (i) the governor to allow the engine to lapse back onto diesel under heavy overload, (ii) variation of pilot injection with engine speed particularly to compensate for variations of injection pump efficiency at different speeds.
It is believed therefore that the present invention in the form as~claimed or the more preferred form hereinbefore described should find wide spread acceptance.
~ 11 --<
Claims (11)
1. A compression ignition engine having a pilot liquid fuel feed to the engine and a separate gaseous fuel feed characterized in that the separate gaseous fuel feed is controlled by means controlled by hydraulic pressure dependent on engine speed and/or engine load.
2. An engine as claimed in claim 1 wherein said means controlling said separate gaseous fuel feed is a valve.
3. An engine as claimed in claim 2 wherein said valve is a piston type valve.
4. An engine as claimed in claim 2 wherein said valve is a diaphragm type valve.
5. An engine as claimed in claim 1 wherein for each engine speed when the engine is running the hydraulic pressure has a predetermined maximum value there being bleeding off circuitry to enable reductions of hydraulic pressure below said maximum value for each engine speed.
6. An engine as claimed in claim S wherein means is provided whereby under low load conditions engine speed governor means cause the bleeding off circuitry to cause a reduction in hydraulic pressure and hence gaseous fuel feed for the particular engine speed.
7. An engine as claimed in claim 1 wherein said hydraulic pressure is dependent on engine speed and the means which\controls the separate gaseous fuel feed is a regulator valve dependent on such hydraulic pressure, said regulator valve and the hydraulic pressure being arranged such that there is no flow of said separate gaseous fuel feed when the engine is not running.
8. A compression ignition engine of a kind having a pilot liquid fuel feed into each combustion chamber and having a gaseous fuel feed to each combustion chamber characterized in that there is provided:-means dependent on engine speed to generate a hydraulic pressure which increases with engine speed, means to govern the effect of load on any engine speed, means responsive to said means to govern to reduce said hydraulic pressure in low load situations to result in a resultant hydraulic pressure less than otherwise would be the case, and means dependent on said resultant hydraulic pressure to control the feed of said gaseous fuel, the arrangement being such that when the engine is not running said means dependent on said resultant hydraulic pressure does not allow a gaseous fuel feed and such that for each speed there is a feed rate of gaseous fuel dependent on said resultant hydraulic pressure, the greatest gaseous feed for each engine speed being that when the engine is under
8. A compression ignition engine of a kind having a pilot liquid fuel feed into each combustion chamber and having a gaseous fuel feed to each combustion chamber characterized in that there is provided:-means dependent on engine speed to generate a hydraulic pressure which increases with engine speed, means to govern the effect of load on any engine speed, means responsive to said means to govern to reduce said hydraulic pressure in low load situations to result in a resultant hydraulic pressure less than otherwise would be the case, and means dependent on said resultant hydraulic pressure to control the feed of said gaseous fuel, the arrangement being such that when the engine is not running said means dependent on said resultant hydraulic pressure does not allow a gaseous fuel feed and such that for each speed there is a feed rate of gaseous fuel dependent on said resultant hydraulic pressure, the greatest gaseous feed for each engine speed being that when the engine is under
Claim 8 continued...
load sufficient to minimize the reduction of said hydraulic pressure by said means responsive to said means to govern.
load sufficient to minimize the reduction of said hydraulic pressure by said means responsive to said means to govern.
9. An engine as claimed in claim 8 wherein said means to govern is a mechanical govern constrained from adjusting the liquid fuel feed and instead arranged to coact with said means responsive to said means to govern.
10. An engine as claimed in claim 8 wherein said gaseous feed is into the inlet manifold or manifolds of the engine.
11. An engine as claimed in claim 8 wherein said means responsive to said means to govern is a bleeding circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000405749A CA1203132A (en) | 1982-06-22 | 1982-06-22 | Duel fuel system for compression ignition engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000405749A CA1203132A (en) | 1982-06-22 | 1982-06-22 | Duel fuel system for compression ignition engine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1203132A true CA1203132A (en) | 1986-04-15 |
Family
ID=4123076
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000405749A Expired CA1203132A (en) | 1982-06-22 | 1982-06-22 | Duel fuel system for compression ignition engine |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1203132A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003048555A1 (en) * | 2001-12-04 | 2003-06-12 | Truckgas Pty Ltd | Fuel control system and method |
| WO2003076788A1 (en) * | 2002-03-08 | 2003-09-18 | I-Sense Pty Ltd | Dual fuel engine control |
| US8935078B1 (en) | 2012-01-14 | 2015-01-13 | Anthony Richard Lorts | Hydraulic servo gas regulator for multi-fuel engine |
| US9494089B1 (en) | 2012-01-14 | 2016-11-15 | Anthony Lorts | Hydraulic servo gas regulator for multi-fuel engine |
-
1982
- 1982-06-22 CA CA000405749A patent/CA1203132A/en not_active Expired
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003048555A1 (en) * | 2001-12-04 | 2003-06-12 | Truckgas Pty Ltd | Fuel control system and method |
| AU2002365668B2 (en) * | 2001-12-04 | 2009-02-05 | Truckgas Pty Ltd | Fuel control system and method |
| WO2003076788A1 (en) * | 2002-03-08 | 2003-09-18 | I-Sense Pty Ltd | Dual fuel engine control |
| US7093588B2 (en) | 2002-03-08 | 2006-08-22 | I-Sense Pty Ltd | Dual fuel engine control |
| US8935078B1 (en) | 2012-01-14 | 2015-01-13 | Anthony Richard Lorts | Hydraulic servo gas regulator for multi-fuel engine |
| US9494089B1 (en) | 2012-01-14 | 2016-11-15 | Anthony Lorts | Hydraulic servo gas regulator for multi-fuel engine |
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