GB2150368A - Fuel injection control apparatus - Google Patents
Fuel injection control apparatus Download PDFInfo
- Publication number
- GB2150368A GB2150368A GB08330468A GB8330468A GB2150368A GB 2150368 A GB2150368 A GB 2150368A GB 08330468 A GB08330468 A GB 08330468A GB 8330468 A GB8330468 A GB 8330468A GB 2150368 A GB2150368 A GB 2150368A
- Authority
- GB
- United Kingdom
- Prior art keywords
- coil
- current
- valve
- drive means
- current drive
- 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.)
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Classifications
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- 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]
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- 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
- F02D19/02—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 gaseous fuels
- F02D19/021—Control of components of the fuel supply system
- F02D19/023—Control of components of the fuel supply system to adjust the fuel mass or volume flow
- F02D19/024—Control of components of the fuel supply system to adjust the fuel mass or volume flow by controlling fuel injectors
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- 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
- F02D41/20—Output circuits, e.g. for controlling currents in command coils
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
- F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
- F02M21/0218—Details on the gaseous fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
- F02M21/0248—Injectors
- F02M21/0251—Details of actuators therefor
- F02M21/0254—Electric actuators, e.g. solenoid or piezoelectric
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
- H03K17/60—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being bipolar transistors
- H03K17/64—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being bipolar transistors having inductive loads
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
- H03K17/60—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being bipolar transistors
- H03K17/66—Switching arrangements for passing the current in either direction at will; Switching arrangements for reversing the current at will
- H03K17/661—Switching arrangements for passing the current in either direction at will; Switching arrangements for reversing the current at will connected to both load terminals
- H03K17/662—Switching arrangements for passing the current in either direction at will; Switching arrangements for reversing the current at will connected to both load terminals each output circuit comprising more than one controlled bipolar transistor
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- 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
- F02D41/20—Output circuits, e.g. for controlling currents in command coils
- F02D2041/2017—Output circuits, e.g. for controlling currents in command coils using means for creating a boost current or using reference switching
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- 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
- F02D41/20—Output circuits, e.g. for controlling currents in command coils
- F02D2041/202—Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit
- F02D2041/2058—Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit using information of the actual current value
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- 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
- F02D41/20—Output circuits, e.g. for controlling currents in command coils
- F02D2041/2068—Output circuits, e.g. for controlling currents in command coils characterised by the circuit design or special circuit elements
- F02D2041/2072—Bridge circuits, i.e. the load being placed in the diagonal of a bridge to be controlled in both directions
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- 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
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Analytical Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
Fuel injection apparatus for a liquid petroleum i.c. engine includes a valve for opening and closing an injection nozzle and a coil (AB) mounted for movement with the valve, the coil being placed in a magnetic field so that current passing through it causes the coil and valve to move. Current pulses are supplied to the coil alternately in opposite directions by transistors (20a, 21a, 20b, 21b to cause the coil and valve to open and close the nozzle in dependence upon the duration of control pulses synchronised with induction strokes of the engine. Each current pulse has an initial high current to move the valve and a second lower current to maintain it in its new position. The coil current is regulated by comparators (25a, 25b) switching the transistors at a high frequency. <IMAGE>
Description
SPECIFICATION
Fuel injection apparatus
This invention relates to fuel injection apparatus for internal combustion engines.
Our co-pending United Kingdom Patent Application No. 8307084 describes an air fuel induction system for a spark ignition internal combustion engwne in which a metered supply of fuel, in a typical case, liquid petroleum gas, is admitted to the air/fuel induction passage of an internal combustion engine. The fuel is supplied via injection means including a nozzle, a valve and a coil situated within a magnetic field. Movement of the valve to open or shut the nozzle is controlled by movement of the coil in response to the electric current flowing through the coil.
In contrast to conventional moving iron valves, the use of a mechanical spring to return the moving element to its closed position is not appropriate for a moving coil in view of its low mass.
Although a light spring may be provided to assist the return of the valve to its closed position, the major part of the return force must be provided by an electric current in the moving coil itself. As a result the moving coil is required to be supplied with current in one direction to open the valve and in the reverse direction to close it. Furthermore, to overcome mechanical inertia of the system the coil needs to be provided with an initial high current pulse to start the valve moving, immediately followed by a period of a lower level current to complete the movement and maintain the valve in either the open or shut position depending upon the polarity of the applxed voltage. The valve is thus required to operate in a cyclic manner with alternate pulses of opposite polarity, each pulse having a high initial portion followed by a lower steady portion.The frequency of the changes in polarity in a typical fuel valve is required to be of the order of 1000 cps.
Normal vehicles have only a +12 volts supply rail from which to obtain a source of drive voltage and it is therefore not possible to reverse the current polarity by switching one terminal of the coil to a negative supply. It is difficult to achieve the required operating characteristics with such a limited electrical supply. The present invention seeks to provide a moving coil fuel injection valve having drive circuits which overcome this difficulty.
.According to the present invention there is provided a fuel injection apparatus for an internal combustion engine, comprising: an injection nozzle; a valve adapted for movement between first and second positions at which, respectively, it opens or closes said nozzle;
means providing a magnetic field; an electricallyconducting coil mounted for movement with said valve and within said magnetic field, so that current passing through the coil causes the coil and hence the valve to move;
the fuel injection apparatus being, in use, provided with control pulses synchronised with induction strokes of the engine and having a duration corresponding to a computed valve opening period; and including an electrical circuit arranged to receive said control pulses and operative to supply current to the coil from a voltage source of single polarity with respect to circuit ground, characterised in that the circuit comprises first current drive means connected to said coil and operative to supply current in a first direction through the coil and second current drive means connected to said coil and operative to supply current in the reverse direction through the coil, the first and second current drive means being operated alternately to move the coil and hence the valve from its second to its first position and from its first to its second position respectively in dependence upon the duration of said control pulses.
The electrical circuit comprising the two current drive means is preferably in the form of an integrated circuit.
In one embodiment of the invention the current through the coil, upon operation of each of the current drive means, comprises an initial current of a first value to move the valve from its existing position followed by current of a second and smaller value to maintain the valve in its new position.
In such an embodiment the first and second current drive means may each include a respective negative feedback loop including a comparator connected to receive at one input terminal a voltage from a point in the current supply path to the coil, and at the other input a reference voltage, and operative to provide a correction signal when these voltages differ, wherein the reference voltage is derived from, and synchronised with, the train of said control pulses, such that the reference voltage applied to the first current drive means corresponds in duration to said control pulses and the reference voltage applied to the second current drive means corresponds in duration to the space between the control pulses, and wherein the apparatus includes waveform generating means operative to generate said reference voltage such that upon each application of a reference voltage to either of the current drive means it comprises a two-level voltage determining the duration and magnitude of said first and second values of the currents upon each operation of the current drive means.
In a preferred form the current is supplied to the coil by the current drive means in switched mode form, the frequency of the switching being high relative to the switching between the first and said current drive means.
In one application of the present invention it constitutes a fuel injector for liquid petroleum gas in a dual fuel supply system for an i.c. engine.
An embodiment of the invention will now be described by way of example only, with reference to the accompanying drawings. In the drawings:
Figure 1 is a sectioned view of an LPG injector incorporating the present invention;
Figure 2 is an end elevation view of the valve of the injector of Figure 1, drawn on a reduced scale compared to that of Figure 1;
Figure 3 is a sectional view on the line IV-IV of
Figure 2, with the coil and its leads superimposed thereon;
Figure 4 is a block current diagram of the drive circuitry for the coil;
Figure 5 shows a graph showing a typical variation with time of the current to the coil of the valve; and
Figure 6 shows waveforms at various points in the circuit of Figure 4.
Figure 1 shows an injector for gaseous LPG for use in a dual fuel supply system which is operable to supply metered quantities of either petrol or gaseous LPG to an induction passage of a carburetter fitted to a multi-cylinder internal combustion engine. The petrol or gaseous LPG is supplied to an induction passage communicating with an inlet manifold of the engine at a location upstream of a driver operable throttle valve. The fuel is mixed with air which is drawn into the induction passage by the operation of the engine. Reference is made to our co-pending application no. 8307084 for a detailed description of the dual fuel supply system.
The injector 1 comprises a digital valve havingopened and closed positions and which alternates between these states; the frequency of opening and the duration of the opening period being controlled by a microprocessor-based control unit.
Referring to Figure 1 in detail, the injector 1 comprises a body 2 of non-magnetic material which has a cylindrical cavity 3 and two substantially parallel open-ended bores 4, 5 formed in it, the cavity 3 being formed in one side of the body 2, and the bores extending from the cavity 3 to the opposite side of the body 2. One of the two bores 4 forms a gas inlet. The other bore 5 communicates with the injector outlet and has a tubular valve seat 6 spigotted into it and projecting from it into the cavity 3. The bore of the tubular valve seat 6 serves as an injection nozzle. An 0-ring 7 is fitted to the valve seat 6 so that it surrounds the bore of the valve seat 6 at the one end thereof which projects into the cavity 3.
The cavity 3 is closed by a circular magnet assembly which is clamped to the body 2, conveniently by a beam 8 and two bolts 9. The magnet assembly comprises an annular ceramic magnet 10 sandwiched between an annular pole piece 11 and a radial flange of a circular pole piece 12. The annular pole piece 11 abuts the body 2 and an 0-ring 13, which is trapped between the pole piece 11 and the body 2, seals the cavity 3 against leakage of gas between the body 2 and the annular pole piece 11. The circular pole piece 12 has a circular boss portion which projects coaxially from the radial flange portion through the central cavity of the annular magnet 10 with a significant clearance, and through the central cavity of the annular pole piece 11 with a smaller clearance.
A tubular bush 14 is spigotted into a blind bore which is formed substantially coaxially with the tubular valve seat 6 in the end of the boss portion of the circular pole piece 12 that faces the valve seat 6 across the cavity 3. An annular shoulder is formed adjacent the end of the bush 14 that is nearer to the valve seat 6. A flanged tubular guide 15 of a valve 16 is a sliding fit in the bore of the tubular bush 14.
Figures 1 to 3 show that the valve 16 comprises a cup-shaped body 17, the guide 15 being located coaxially within the cavity of the body 17 and being fixed to the base of the body 17 by its flanged end. A coil of electricaliy-conducting material 18 is wound around the outer surface of the body 17 adjacent its rim and is bonded rigidly to the body 17. Flying flexible leads 19 and 20 are connected to the ends of the coil 18.
The body 17 is formed of aluminium, for example, by being pressed from aluminium sheet.
Hence the valve 16 is a lightweight structure just capable of carrying the coil 18 and forms no part of the permanent magnetic circuit formed by the magnet 10 and the pole pieces 11 and 12.
Figure 1 shows that a light spring 21 has one end turn seated in the annular shoulder formed on the bush 14. The spring 21 reacts against the bush 14 to hold the base of the valve body 17 against the 0-ring 7 which serves as a resilient seating for the valve 16 as well as a gas seal. The dimensions of the valve body 17 are such that the coil 18 is always positioned in the gap between the annular pole piece 11 and the central boss portion of the pole piece 12. An 0-ring 22, which is fitted in the annular shoulder formed between the flange and tubular portions of the flanged tubular guide 15, co-operates with the nearer end of the tubular bush 14 and thereby serves as a resilient stop to limit movement of the valve 16 away from the valve seat 6.Rectilinear movement of the valve 16 relative to the valve seat 6 is guided by the tubular portion of the flanged tubular guide 15 sliding within the bore of the tubular bush 14.
The flying leads 19 and 20 pass through sealed holes (not shown) which are formed in the body 2.
The leads 19 and 20 are connected to respective output terminals of the drive circuit of the electrical control system.
A solenoid operated shut-off valve of the petrol system is closed and a solenoid operated shut-off valve of the LPG system is opened when the engine is to be fuelled by LPG.
Durating operation of the LPG system, gaseous
LPG at the regulated superatmospheric pressure, which preferablySis constant, is supplied to the inlet of the injector 1.
A microprocessor-based electronic control unit determines the quantity of fuel to be admitted to the engine in accordance with prevailing conditions. The control unit is connected to various transducers for sensing operating parameters of the engine. The control unit has a main look-up matrix which is addressed by the sensed value of engine speed and absolute pressure in the inlet manifold. The read-out value is modified by the values of other sensed parameters. The resultant output from the control unit is a succession of pulses synchronised with the induction strokes of the engine and the width of each pulse is indicative of the quantity of fuel required to be delivered upon that stroke in accordance with the sensed prevailing conditions. This pulse is used to control the operation of the LPG supply valve via drive circuitry to the operating coil 18 which is now described.
Referring to Figure 4, an integrated circuit providing the operating current to the moving coil 18 comprises two symmetrical driver units, the driver units being operated alternately to provide respectively forward and reverse currents through the coil 18 to move it in its two directions.
The two driver units include identical components. One of the two units is now described with the components designated with a reference a, the corresponding components in the other unit are designated with the same reference numeral but with a reference b. The driver unit includes two
NPN transistors 20a and 21a each connected between a respective terminal of the coil 18 and either the +12 volts or 0 volts lines. The collector terminal of transistor 20a is connected to the +12 volts supply line and its emitter terminal is connected to terminal B of the coil 18. The collector terminal of transistor 21a is connected to the terminal A of coil 18 and its emitter terminal is connected to the 0 volts line via a resistor 33a. In the other driver unit transistor 20b is connected to terminal A of the coil and transistor 21b is connected to terminal B of the coil.
The anode of a diode 29 is connected to terminal
A of the coil 18, and its cathode to the +12 volts line. The cathode of a further diode 30 is connected to terminal A and its anode to the 0 volts line. Diodes 31 and 32 are connected to terminal B of the coil 18 analogously to diodes 29 and 30.
The base currents to the transistors 20a and 21a are controlled by respective drive circuits 22a and 24a which in turn are controlled by signals derived via a control loop. The control loop comprises a comparator 25a having one input connected to the emitter terminal of transistor 21a and its other input connected to a terminal to which a reference voltage VREFI (VREF2 in the case of the other driver unit) is applied.
The output terminal of the comparator 25a is connected to the SET input of an RS flip-flop 26a.
The RESET input to the flip-flop 26a is connected to an oscillator 23 common to both driver units.
The oscillator operates at a frequency of 20-30 kHz.
The Q output from the flip-flop 26a is connected to logic circuitry 27a which has a further input from a select gate 28. The select gate has three inputs.
The EN input simply enables the select gate circuitry. Signals V1 and V2 are taken high alternately to define which of the two output drive stages 22a/ 24a or 22b/24b are operative.
The logic circuitry 27a produces output signals which are fed to the two drive circuits 22a and 24a to control the base currents to the transistors.
The driver unit is activated by a HIGH logic signal V1 from the microprocessor-based control unit in the vehicle (described further below). This signal operates the select gate 28 which operates the logic circuitry 27a. The microprocessor control unit simultaneously provides the reference voltage
VREF1. The logic circuitry signals the drive circuits 22a and 24a to provide a saturating base current to both transistors 20a and 21a, switching them on.
Current through the coil 18 increases exponentially until the voltage across the resistor 33a reaches
VREFI. This changes the output state of the comparator 25a which is fed as a SET signal to the flipflop 26a causing its Q output to change state. The logic circuitry 27a modifies the signal to the drive circuit 22 of transistor 20a in response to the change of state of the flip-flop, but maintains the base current to transistor 21a. In particular transistor 20a is switched off when the SET signal is fed to the flip-flop, removing the current through the coil 18 and causing a back emf. The terminal B of the coil goes negative with respect to terminal A and current flows through transistor 21a, resistor 33a and back to coil 18 through the 0 volts line and diode 32, thus discharging energy stored in the coil.The transistor 20a is switched on again in synchronism with a pulse from the oscillator 23 to the flip-flop 26a when the voltage across resistor 33a has dropped to VREFI, by which time several clock pulses may have been produced. The comparator 25a has hysteresis so that transistor 20a is switched off at a somewhat lower voltage across resistor 33a than that at which it is switched on.
The Q output from the flip-flop 26a is thus a pulsed waveform, with basically a 20 KHz repetition rate. The initial period of operation is not pulsed since the time during which the voltage across resistor 33a rises to VREFI is less than the period of the oscillator. This arrangement thus provides an operating current to the coil 18 of a 'switched mode' type with the consequent advantage of low power dissipation, as is well known in the art.
The diodes 29 and 31 protect the output transistors, clamping with both sides of the coil 18 to the +VE supply rail.
As is stated above, to move the valve 16, either in the opening or closing direction, an initial larger force, corresponding to a larger current through the coil 18, must be provided. This is then followed by a reduced holding force. Figure 5 shows a typical variation of coil drive current with time. Each pulse comprises an initial portion of approximately 6 amps applied for a fixed period in each pulse.
This is 17 followed by a hold current of approximately 1 amp, the duration of which is controlled by the microprocessor-based control unit in accordance with fuel requirements.
Figures 6 (a) and 6 (b) show the output pulses from the microprocessor-based control unit which are applied respectively to the VI and the V2 inputs to the driver units. These pulses are also fed to a waveform generator unit which produces the voltage waveform shown in Figures 6 (c) and 6 (d), comprising the two level pulses determining the coil current. The voltage shown in Figure 6 (c) derived from V1 is supplied as the reference voltage
VREFI, and the voltage shown in Figure 6 (d) derived from V2 is supplied as the reference voltage VREF2.
The select gate enabling input EN is maintained at a low level thereby enabling both of the driver units. The pulses V1 and V2 operate the first and second driver units alternately and in synchronisation with the appropriate reference voltage VREF1 or VREF2. In this way the driver units are operated alternately to produce currents in opposite directions through the 18 coil 18. The valve 6 is thereby moved repeatedly between its open and closed positions allowing controlled quantities of LPG fuel to be admitted into the induction passage.
Claims (8)
1. Fuel injection apparatus for an internal combustion engine, comprising: an injection nozzle, a valve adapted for movement between first and second positions at which, respectively, it opens or closes said nozzle, means providing a magnetic field, an electrically-conducting coil mounted for movement with said valve and within said magnetic field so that current passing through the coil causes the coil and hence the valve to move;
the fuel injection apparatus being, in use provided with control pulses synchronised with induction strokes of the engine and having a duration corresponding to a computed valve opening period; and including an electrical circuit arranged to receive said control pulses and operative to supply current to the coil from a voltage source of single polarity with respect to circuit ground, characterised in that the circuit comprises first current drive means connected to said coil and operative to supply current in a first direction through the coil and second current drive means connected to said coil and operative to supply current in the reverse direction through the coil, the first and second current drive means being operated alternately to move the coil and hence the valve from its second to its first position and from its first to its second position respectively in dependence upon the duration of said control pulses.
2. Fuel injection apparatus as claimed in claim 1 wherein the electrical circuit comprising the two current drive means is in the form of an integrated circuit.
3. Fuel injection apparatus as claimed in claim 1 or claim 2 wherein, upon operation of each of the current drive means, the current through the coil comprises an initial current of a first value to move the valve from its existing position followed by current of a second and smaller value to maintain the valve in its new position.
4. Fuel injection apparatus as claimed in claim 3 wherein the first and second current drive means each includes a respective negative feedback loop including a comparator connected to receive at one input terminal a voltage from a point in the current supply path to the coil, and at the other input a reference voltage, and operative to provide a correction signal when these voltages differ, wherein the reference voltage is derived from, and synchronised with, the train of said control pulses, such that the reference voltage applied to the first current drive means corresponds in duration to said control pulses and the reference voltage applied to the second current drive means corresponds in duration to the space between the control pulses, and wherein the apparatus includes waveform generating means operative to generate said reference voltage such that upon each application of a reference voltage to either of the current drive means it comprises a two-level voltage determining the duration and magnitude of said first and second values of the currents upon each operation of the current drive means.
5. Fuel injection apparatus as claimed in any of tne preceding claims wherein the current is supplied to the coil by the current drive means in switched mode form, the frequency of the switching being high relative to the switching between the first and second current drive means.
6. Fuel injection apparatus as claimed in any of the preceding claims, used as a fuel injector for liquid petroleum gas in a dual fuel supply system for an i.c. engine.
7. Fuel injection apparatus substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.
8. A fuel injector for liquid petroleum gas substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08330468A GB2150368A (en) | 1983-11-15 | 1983-11-15 | Fuel injection control apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08330468A GB2150368A (en) | 1983-11-15 | 1983-11-15 | Fuel injection control apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8330468D0 GB8330468D0 (en) | 1983-12-21 |
| GB2150368A true GB2150368A (en) | 1985-06-26 |
Family
ID=10551786
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08330468A Withdrawn GB2150368A (en) | 1983-11-15 | 1983-11-15 | Fuel injection control apparatus |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2150368A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0247675A1 (en) * | 1986-05-26 | 1987-12-02 | AT&T NETWORK SYSTEMS NEDERLAND B.V. | Transmitter for ISDN S-bus interface circuit |
| EP0653556A2 (en) * | 1993-10-29 | 1995-05-17 | Precision Engine Controls Corporation | Air/fuel ratio controller for large internal combustion engines |
| GB2300306A (en) * | 1995-04-25 | 1996-10-30 | Pectel Control Systems Ltd | Drive circuits for fuel injector solenoids |
| EP1701026A1 (en) * | 2005-03-09 | 2006-09-13 | Siemens Aktiengesellschaft | Method for controlling a solenoid injector |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1230715A (en) * | 1968-11-13 | 1971-05-05 | ||
| GB1265019A (en) * | 1968-12-04 | 1972-03-01 | ||
| GB1405848A (en) * | 1972-01-29 | 1975-09-10 | Bosch Gmbh Robert | Internal combustion engines |
| GB1427995A (en) * | 1972-03-03 | 1976-03-10 | Hitachi Ltd | Fuel feed control device for internal combustion engine |
| GB1428353A (en) * | 1973-02-07 | 1976-03-17 | Hitachi Ltd | Fuel feed control device for internal combustion engine |
| GB2069185A (en) * | 1979-11-27 | 1981-08-19 | British Leyland Cars Ltd | Automatic control of engine speed |
-
1983
- 1983-11-15 GB GB08330468A patent/GB2150368A/en not_active Withdrawn
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1230715A (en) * | 1968-11-13 | 1971-05-05 | ||
| GB1265019A (en) * | 1968-12-04 | 1972-03-01 | ||
| GB1405848A (en) * | 1972-01-29 | 1975-09-10 | Bosch Gmbh Robert | Internal combustion engines |
| GB1427995A (en) * | 1972-03-03 | 1976-03-10 | Hitachi Ltd | Fuel feed control device for internal combustion engine |
| GB1428353A (en) * | 1973-02-07 | 1976-03-17 | Hitachi Ltd | Fuel feed control device for internal combustion engine |
| GB2069185A (en) * | 1979-11-27 | 1981-08-19 | British Leyland Cars Ltd | Automatic control of engine speed |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0247675A1 (en) * | 1986-05-26 | 1987-12-02 | AT&T NETWORK SYSTEMS NEDERLAND B.V. | Transmitter for ISDN S-bus interface circuit |
| EP0653556A2 (en) * | 1993-10-29 | 1995-05-17 | Precision Engine Controls Corporation | Air/fuel ratio controller for large internal combustion engines |
| EP0653556A3 (en) * | 1993-10-29 | 1996-02-21 | Precision Engine Controls Corp | Air/fuel ratio controller for large internal combustion engines. |
| GB2300306A (en) * | 1995-04-25 | 1996-10-30 | Pectel Control Systems Ltd | Drive circuits for fuel injector solenoids |
| GB2300306B (en) * | 1995-04-25 | 2000-02-09 | Pectel Control Systems Ltd | Fluid injector systems |
| EP1701026A1 (en) * | 2005-03-09 | 2006-09-13 | Siemens Aktiengesellschaft | Method for controlling a solenoid injector |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8330468D0 (en) | 1983-12-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |