Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
  • F02D19/06—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
  • F02D19/0602—Control of components of the fuel supply system
  • F02D19/0605—Control of components of the fuel supply system to adjust the fuel pressure or temperature
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
  • F02D19/06—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
  • F02D19/0602—Control of components of the fuel supply system
  • F02D19/0607—Control of components of the fuel supply system to adjust the fuel mass or volume flow
  • F02D19/061—Control of components of the fuel supply system to adjust the fuel mass or volume flow by controlling fuel injectors
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
  • F02D19/06—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
  • F02D19/0626—Measuring or estimating parameters related to the fuel supply system
  • F02D19/0628—Determining the fuel pressure, temperature or flow, the fuel tank fill level or a valve position
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
  • F02D19/06—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
  • F02D19/0639—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels
  • F02D19/0642—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels at least one fuel being gaseous, the other fuels being gaseous or liquid at standard conditions
  • F02D19/0647—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels at least one fuel being gaseous, the other fuels being gaseous or liquid at standard conditions the gaseous fuel being liquefied petroleum gas [LPG], liquefied natural gas [LNG], compressed natural gas [CNG] or dimethyl ether [DME]
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
  • F02D19/06—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
  • F02D19/08—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed simultaneously using pluralities of fuels
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
  • F02D19/06—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
  • F02D19/08—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed simultaneously using pluralities of fuels
  • F02D19/081—Adjusting the fuel composition or mixing ratio; Transitioning from one fuel to the other
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/24—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means
  • F02D41/26—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using computer, e.g. microprocessor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/30—Controlling fuel injection
  • F02D41/3094—Controlling fuel injection the fuel injection being effected by at least two different injectors, e.g. one in the intake manifold and one in the cylinder
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/30—Controlling fuel injection
  • F02D41/38—Controlling fuel injection of the high pressure type
  • F02D41/3809—Common rail control systems
  • F02D41/3836—Controlling the fuel pressure
• • 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
  • F02B3/00—Engines characterised by air compression and subsequent fuel addition
  • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
  • F02D19/06—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
  • F02D19/0663—Details on the fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
  • F02D19/0686—Injectors
  • F02D19/0689—Injectors for in-cylinder direct injection
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D2400/00—Control systems adapted for specific engine types; Special features of engine control systems not otherwise provided for; Power supply, connectors or cabling for engine control systems
  • F02D2400/11—After-sales modification devices designed to be used to modify an engine afterwards
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
  • F02D41/0027—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures the fuel being gaseous
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/24—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means
  • F02D41/26—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using computer, e.g. microprocessor
  • F02D41/266—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using computer, e.g. microprocessor the computer being backed-up or assisted by another circuit, e.g. analogue
• • 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

Definitions

• This invention is concerned with improving the fuel efficiency of fuel injected diesel or petrol engines in order to effect within the engine the principle of homogenous combustion, i.e., to ensure that fuel is utilised (burnt) as fully as possible thus improving the efficiency of the engine and bringing about a reduction of harmful exhaust emissions.
• homogenous implies complete burn of all fuel, which is not achievable in practical terms, but nevertheless this is to be desired to avoid emission of unburnt fuel that may be harmful to the environment.
• hydrocarbon fuels such as diesel have a molecular structure which is long, complex and slow to combust which prevents some hydrocarbon fractions from burning fully. Again in the case of diesel engines this is largely responsible for smoke and particulate matter issuing from the exhaust system of the engine.
• a conventional diesel engine on a heavy commercial vehicle has an effective diesel burn of between 75% and 80% of its total capability and it is a further object of the present invention to increase this to a level much closer to 100%.
• US-A- 4463734 discloses a diesel engine in which increasing proportions of liquefied petroleum gas (LPG) are metered to the engine as power demand increases, starting from as little as 20% gas and increasing to about 80% gas, where the percentage is given in calorific value.
• LPG liquefied petroleum gas
• the calorific value of LPG is about 60% that of diesel so that, in terms of liquid volume, the percentage range is between 30% and 87% of gas. Different gases have different calorific values.
• US-A-4641625 discloses a range of gaseous fuel in a liquid gas mixture of between 0 and 95% gas.
• US-A-6026787 and US-A-2005/0205021 both disclose dual fuel engines, but without specifying the proportions of the fuels.
• a method of improving the fuel efficiency of an electronically controlled fuel injected internal combustion engine comprising the steps of controlling the quantity of a first fuel having a first molecular structure injected into a combustion chamber of the engine during a combustion cycle, and sequentially supplying to the combustion chamber a controlled proportional quantity of a second fuel of a shorter molecular structure, wherein the amount by calorific value of the second fuel injected is limited to between 5 and 25% of the total fuel employed.
• the amount in liquid form of the second fuel injected is limited to between 5 and 25% of the total fuel employed in liquid form.
• the present invention ensures a more complete burn of the hydrocarbon fuel by introducing said second fuel or fuels to act as an accelerant within the combustion chamber.
• the invention recognises several facts.
• the first is that only a small amount of gas (which is used herein interchangeably with the term “second fuel” - indeed, "fuel” should be interpreted to include a mixture of more than one fuel, as well as a single fuel) is needed to improve the combustion of the first fuel, which may be diesel or petrol or any long chain fuel that is liquid at ambient temperatures and pressures.
• the gas mixes easily with the air and gets to all corners of an engine's combustion chamber. Moreover it burns easily so that it, at least, is entirely combusted and in doing so ensures that all the heavier first fuel ignites also. At least, a greater majority of the fuel is combusted. Accordingly, the efficiency of the engine is enhanced.
• the amount of gas injected is so small that the overall engine management control system is not adversely affected, whereby the gas added is simply additional to the diesel injected for the engine operational conditions responsive to the throttle position determined by the operator or the control system. That is to say, the improved efficiency is simply seen by the management system as a reduced load on the engine, leading to increased speed, and is not perceived as an error condition. However, this depends to some extent on the system in which the engine is fitted,
• the controlled quantity of the first fuel injected into the combustion chamber may be determined by a microprocessor which produces a signal to determine the proportional quantity of the second fuel and the sequential timing of injection thereof into the combustion chamber.
• the controlled quantity of the first fuel may be determined by measuring the normal duration of a pulsed supply of the first fuel by an injector as determined by an engine management computer or powertrain control module (PCM).
• PCM powertrain control module
• the pulsed supply of the first fuel may be interrupted at a predetermined point in time, the proportional quantity of the second fuel being introduced into the combustion chamber at a subsequent point in time coincident with a combustion stroke of the engine.
• Said introduction of the second fuel may be by direct injection into the combustion chamber, during the induction stroke, compression stroke or combustion stroke of the engine.
• said injection is into an inlet manifold of the engine behind an inlet valve of each combustion chamber of the engine during the induction stroke of the chamber in question.
• the proportion of said second fuel injected during said induction stroke is determined on the basis of the amount of first fuel injected in a preceding combustion cycle of the engine, ideally an immediately preceding cycle.
• injection into said inlet manifold begins after all outlet valves of the chamber in question have closed in or following the preceding exhaust stroke of the engine.
• injection into said inlet manifold ceases before the inlet valve of the chamber in question closes in or following said induction stroke of the engine.
• the controlled quantity of the first fuel may be determined by monitoring the duration of the supply of the first fuel by an injector in relation to a signal representative of the instantaneous fuel pressure derived from a fuel pump, and interrupting the supply at a predetermined point in time.
• a signal may be sent to the fuel pump to modify the fuel pressure in addition to, or as an alternative to, modification of the duration of a pulsed fuel supply to the combustion chamber of the engine.
• the second fuel may be liquefied petroleum gas (LPG).
• the second fuel may be hydrogen.
• the second fuel may comprise two or more different fuels of different molecular structures.
• the second fuel may be injected into the air stream supplied to the combustion chamber of the engine. Preferably, there is between 5 and 15% of the second fuel, in calorific value, or in liquid form by volume.
• a method of improving the fuel efficiency of an electronically controlled fuel injected internal combustion diesel engine comprising the steps of controlling the quantity of a first diesel fuel having a first molecular structure injected into a combustion chamber of the engine during a combustion cycle, and sequentially supplying to the combustion chamber a controlled proportional quantity of a second fuel of a shorter molecular structure, wherein the amount of the second fuel injected is limited so that the calorific value of the combined fuels injected into the engine for a given level of performance is less than the calorific value of the first fuel needed to achieve the same level of performance when injected alone.
• the aim of the second invention is not to maximise the use of a second, gaseous, fuel, but only to improve the efficiency of the engine, particularly a heavy diesel engine, and its emissions.
• a corollary benefit of the invention is precisely that it does not employ a substantial quantity of the gas. Firstly, this means that a large reservoir of the gas is not required in order to provide a significant range of dual-fuel use before replenishment of the gas is needed. It is to be remembered that in most countries the supply of gas is not universally available, for example in all (or even, many) garage filling-station forecourts. Secondly, while gas is presently less expensive than diesel fuel, this is primarily a present tax policy matter and there is no guarantee that it will remain the case in the future and generally it will not if gas becomes a significant fuel source for vehicles.
• an engine system for dual fuel has the OEM injector lines from the vehicle control module supplied to a processor which chops the pulse length to reduce the quantity of diesel injected.
• the gas is controlled simply by engine vacuum.
• US-A-2005/0205021 discloses independent control of the gas injection by a Flow Control Unit that is controlled by an integrated control unit that takes all parameters into account and determines the appropriate proportion of gas to diesel. Hence it is an integrated system and cannot be a bolt-on system to an existing vehicle. It is hence a relatively complex system.
• EP-A-1281850 discloses a controller that determines pulse widths and timings for engine injectors, which pulse width and timings are used for either diesel or gas. When employed to control diesel injection, there is one algorithm in the control unit. However, when it is used to control gas injection, a different algorithm is employed. [0027] It is a further object of the present invention to provide a convenient method of control of gas injection in a fuel employing both gas and liquid fuel simultaneously. Particularly it is desirous a) to have a system that is easily bolted onto many existing engines to convert them from single liquid fuel to combined fuel use without extensive modification either of the engine or the bolt-on system, and b) to enable vehicle and other engine manufacturers to render engines more easily convertible. Indeed, it is an object of the invention to provide a system that enables vehicle manufacturers (and other engine suppliers) relatively straightforwardly to modify their existing engines to dual-fuel use without the necessity to re-map the engine management system
• a system for improving the fuel efficiency of an electronically controlled fuel injected internal combustion engine comprising: means for supplying a first quantity of a first fuel having a first molecular structure for injection into to a combustion chamber of the engine during a combustion cycle; means for supplying a second quantity of a second fuel of a shorter molecular structure into the combustion chamber; and a first microprocessor controlling said first quantity of fuel according to multiple parameters of the engine; wherein a second microprocessor determines the quantity of the second fuel as a function of the quantity of the first fuel and causes injection of the second quantity sequentially with respect to the first quantity.
• said parameters are the normal parameters detected by an engine management system on the basis of which a fuel quantity is normally determined, such as engine speed and throttle position. Others are, of course, within the ambit of the skilled person.
• the first and second microprocessors may be a single, integrated processor or at least be contained within a single engine management computer or powertrain control module (PCM).
• the system may further comprise: means for measuring the duration of a pulsed supply of a first fuel to the injector; means to monitor the instantaneous pressure of the first fuel derived by a fuel pump; wherein said second microprocessor receives signals from the measuring means and monitoring means; and the second microprocessor is adapted to calculate said first quantity of the first fuel injected and produce and transmit a resultant signal to means for sequentially supplying said second quantity of the second fuel.
• the system may be adapted for connection between an engine management computer (ECU) and a fuel injector for the engine thus to intercept the signals issued by the PCM to the injector and to supply optionally modified signals to the injector.
• the system may comprise means for modifying the pulsed length of the supply of the first fuel.
• the system may include means to modify the instantaneous pressure of the first fuel as a parameter of the supply of the first fuel to the engine.
• the pressure monitoring means may be the second microprocessor adapted to receive signals from, and transmit signals to, a fuel pump for the first fuel.
• the second microprocessor may be connected to the PCM and adapted to transmit signals thereto representative of the overall fuel supply to the engine, thus to emulate normal engine operational conditions as monitored by the PCM.
• the means for measuring the duration of the pulsed supply of the first fuel to the injector may be a Hall Effect current sensing device producing an analogue signal, and connected, via an analogue to digital converter, to the second microprocessor.
• the means for modifying the pulsed length of the supply of the first fuel to the injector may be an optically coupled MOSFET switching block connected to the second microprocessor.
• the Hall Effect current sensor and the optically coupled MOSFET switching block may provide a low-resistance, electrically conductive path completing a circuit between the PCM and the injector.
• An opto-coupler may be connected in parallel to the optically coupled MOSFET switching block to detect any potential difference during an "off" state of the switching block.
• Said function is preferably a proportional function, optionally a linear function.
• Said second quantity of said second fuel may preferably be between 5 and 25% by calorific value of the total fuel employed. It may be between 5 and 25% by liquid volume of the total fuel employed.
• the invention also provides an electronically controlled fuel injected internal combustion engine, suitable for implementing the systems or methods described above, comprising an engine management computer or powertrain control module (PCM) and a fuel injector for the engine, wherein the engine management computer or PCM has an output for connection of a second fuel injection control system and indicative of the instantaneous quantity of fuel injected in each cylinder of the engine during each combustion cycle of the engine.
• PCM powertrain control module
• Fig. 1 is a diagram representing the manner of operation of the system to be described.
• Fig. 2 is a circuit diagram of the system as applied to the PCM and each fuel injector of an engine.
• the method of and system for improving the fuel efficiency of an electronically controlled fuel injected diesel engine is intended to bring about, as completely as possible, homogenous combustion within each cylinder or combustion chamber of the engine in order most effectively to burn the entire quantity of diesel fuel supplied to the combustion chamber and thus increase the effective diesel burn from between 75% to 80% as typically experienced in a conventional diesel engine, to something in the region of 98% to 99% ie, almost 100%.
• the system imposes a control over the fuelling mechanism which, if required, can vary the fuel pressure and/or the duration of the pulsed supply of diesel fuel to the engine.
• the normal performance characteristics can be maintained while efficiency is increased.
• Fig. 1 the system of the present invention is illustrated diagrammatically at 3 and is adapted to receive signals monitoring the injection pulses 1 applied to each injector from the engine management computer (15 in Fig. 2). These may consist of individual pulses or groups of pulses per engine cylinder combustion stroke. The total injection duration is calculated in system 3 and multiplied by a relative voltage 2 representing the fuel pressure derived from a fuel supply pump (16a in Fig. 2). Output data is generated at 4 representing the total fuel quantity delivered to the combustion chamber, and this may consist of one or more of an individual pulse 4a, per combustion, of variable pulse width, a variable voltage/current analogue output 4b, a digital output 4c, or a combination of all three.
• a dotted line X represents a point of connection of the system illustrated below the line X, to an engine management computer or powertrain control module (PCM) and the engine injectors, which are represented above the line X.
• PCM powertrain control module
• the engine to which this system is to be connected will include a series of fuel injectors 1 1 in the form of electrically operated valves, all connected to a common fuel supply rail 12, an engine management computer (PCM) 15 and a fuel pump 16a.
• a pressure sensor 13 produces a signal representative of the instantaneous fuel pressure in the rail 12 and transmits the signal to the PCM 15 which is connected also the fuel pump 16a.
• the system of the invention is connected to the components above the line X by interrupting the normal circuit from the PCM 15 to each injector 1 1 as shown at 14, and so an entire system as illustrated below the line X is required and connected between the PCM 15 and each of the injectors 1 1.
• the intercepted circuit 14 is replaced by a circuit including a Hall Effect current sensing device 17 and an optically coupled MOSFET switching block 18.
• the resultant circuit illustrated by thickened line Y provides a low-resistance, electrically conductive path thus completing the circuit and ensuring any changes made to the injector control circuit characteristics by its insertion are negligible, and completing the circuit between the PCM and the injector.
• An opto-coupler 19 is connected in parallel with the MOSFET switching block 18 to enable detection of any potential difference in the circuit during the MOSFET "off" state, during operation.
• the opto-coupler 19 is connected to a microprocessor 22, an output of which is also connected to the MOSFET switching block 18 while the analogue signal from the Hall Effect current sensor 17 is supplied via a multiplex analogue to digital converter (ADC) 20 to the microprocessor 22.
• ADC analogue to digital converter
• the signal from the pressure sensor 13 is also connected to the microprocessor 22 via ADC 20.
• any or all external circuits having an affect upon or receiving effective signals from the system are represented at 21 and are thus connected to the microprocessor 22 both to receive signals from and to transmit signals to the latter.
• analogue signal voltages from the fuel pressure sensor 3, the Hall Effect current sensing device 7, and external control voltages are converted into digital signals by the ADC 20, while signals from the latter, from the opto-coupler 19, and from external control interface circuits 21 are received and monitored by the microprocessor 22.
• the microprocessor 22 mathematically combines the fuel pressure reading from pressure sensor 13 and the duration of injection pulses as read by the Hall Effect current sensor 17 thus providing a proportional digital output signal from the microprocessor 22 representing the relative quantity of fuel injected into the engine.
• the microprocessor 22 is programmed to enable a fuel injection pulse generated by the PCM 15 and transmitted to the injector 1 1 to be interrupted if necessary at a predetermined point in time by transmitting a signal to the MOSFET switching block 18 thus to turn off the supply pulse at a precise moment, thus prematurely stopping the injection of fuel into the combustion chamber.
• a resultant signal is then transmitted from the microprocessor 22 via the interface 21 to control a second set of injectors (not shown) arranged to inject a pulse or pulses of predetermined length of a second, lighter fuel such as LPG into the air stream supplied to the combustion chamber.
• the timing generated by the microprocessor 22 is such that the injection of secondary fuel coincides with the next induction cycle of the engine.
• the gaseous fuel is injected directly into the combustion chamber shortly after injection of the primary fuel.
• the quantity of fuel to be injected from one combustion cycle to the next seldom changes, and, when it does change, it seldom changes very rapidly substantially or such that this out-of-step fuel injection has any discernible effect, either in acceleration or deceleration of the engine.
• a disadvantage of direct injection is that a) the cylinder head of the engine requires modification and b) the advantage of the gas mixing and disseminating reliably through the entire cylinder volume may be lost. There is the further problem that the fuel will need substantial pressurization to be injected during the compression or combustion stroke of the engine. Consequently, injection into the inlet manifold is preferred.
• a predetermined and controlled injection of diesel fuel takes place during one combustion stroke, while a predetermined quantity of the second fuel is injected into the combustion chamber sequentially, so that the overall fuel supply to the combustion chamber is a sum of the first and second fuels in their predetermined and controlled proportions, the second fuel having a shorter molecular structure ensuring substantially complete combustion of the first fuel thus considerably increasing the efficiency of the engine and reducing carbon emissions from the exhaust as well as smoke and particulate matter.
• the microprocessor 22 may also intercept the fuel pump pressure control signals 16b to cause the fuel pressure to be modified. This is not essential in all cases since the pressure can be a constant while the volume of the fuel supply is controlled and modified as appropriate to maximise efficiency. [0061] Since the system, in this example, is readily connected physically to and between the PCM 15 and injector 1 1 of any electronically controlled fuel injected engine, the microprocessor 22 can be programmed to bring about a control of a single or dual fuel supply to the engine to achieve improved efficiency and reduce emissions, irrespective of the design of the engine or the control imposed over it by the PCM 15. [0062] The system can be used for other purposes by imposing a control over the fuel supplied to the injectors 1 1.
• the system can be used for electronic fuel injection fault diagnosis by providing an injected fuel quantity reference as a means of checking and confirming correct fuel delivery. It can be used to enhance engine performance by injecting a secondary fuel in proportions which serve to increase engine power output.
• the system is fully bi-directional so that it may be connected in either polarity and it is electrically isolated so that high voltages cannot enter the control circuit.
• the system may be used with both diesel and petrol (gasoline) direct injection engines. While in operation current sensing within the circuit is monitored by the Hall Effect sensor 17, and any improper current flow conditions within the circuit can be rectified by switching off the MOSFET switching block 18 thus protecting the circuit from damage.
• the MOSFET switching block is certainly a preferred element of the present invention.
• the MOSFET switching block 18 is omitted.
• the engine management system will do this to some extent automatically, recognizing the improved performance of the engine not as some fault condition but simply as a reduction in engine load. In this event, it is feasible to omit the MOSFET switching block 18 entirely.
• any liquid/gaseous fuel may be used, provided that it is fuel of shorter molecular structure than the diesel or gasoline supplied as the primary fuel.
• lighter secondary fuels include liquefied petroleum gas (LPG), hydrogen, compressed natural gas, and bioethanol.
• the improved thermal efficiency within the internal combustion engine afforded by dual-fuel control as described serves to create a cooler, leaner burn, which will provide improved output in terms of power, torque and energy, while using less overall fuel and producing considerably less harmful emissions, particularly nitrogen oxides, as well as, in the case of diesel fuel, a considerable reduction in particulate matter and smoke.
• this improvement in efficiency is interpreted by the engine's PCM as though it were a reduction in load carried by the vehicle, so the PCM will consequently retard the quantity of diesel fuel supplied and thus improve the economy of the engine in direct proportion to the improvement in engine efficiency.
• Typical results on a large commercial engine are considered to provide a reduction in primary fuel consumption of around 20%, using only 5% to 10% of secondary fuel (by liquid volume) to achieve this improvement. Indeed, volume for volume, less fuel in total is used, and this ignores the fact that diesel fuel has about 1 .6 times more calorific value than LPG in liquid volume terms.
• Emission reductions are typically 40% to 70% reduction in nitrogen oxides, 80% to 90% reduction in smoke and particulate matter, and a reduction of carbon dioxide reflective of the reduction of overall fuel used and the efficiency of the engine.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Computer Hardware Design (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
• Output Control And Ontrol Of Special Type Engine (AREA)

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• 2008
  • 2008-03-20 GB GB0805221A patent/GB2458500A/en not_active Withdrawn
• 2009
  • 2009-03-19 WO PCT/GB2009/050261 patent/WO2009115845A1/en active Application Filing
  • 2009-03-19 EP EP09721783A patent/EP2279339A1/de not_active Withdrawn

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