GB1598043A - Electrically controlled fuel injection systems - Google Patents
Electrically controlled fuel injection systems Download PDFInfo
- Publication number
- GB1598043A GB1598043A GB845378A GB845378A GB1598043A GB 1598043 A GB1598043 A GB 1598043A GB 845378 A GB845378 A GB 845378A GB 845378 A GB845378 A GB 845378A GB 1598043 A GB1598043 A GB 1598043A
- Authority
- GB
- United Kingdom
- Prior art keywords
- control
- discharging
- charging
- transistor
- dependent
- 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
-
- 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
- F02D41/32—Controlling fuel injection of the low pressure type
- F02D41/36—Controlling fuel injection of the low pressure type with means for controlling distribution
- F02D41/365—Controlling fuel injection of the low pressure type with means for controlling distribution with means for controlling timing and distribution
-
- 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
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/18—Circuit arrangements for generating control signals by measuring intake air flow
- F02D41/182—Circuit arrangements for generating control signals by measuring intake air flow for the control of a fuel injection device
Description
(54) IMPROVEMENTS IN AND RELATING TO
ELECTRONICALLY CONTROLLED FUEL INJECTION SYSTEMS
(71) We, ROBERT BOSCH GMBH, a
German company of Postfach 50, 7 Stuttgart 1,
Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:
The present invention relates to electronically controlled fuel injection systems.
It is known to provide an injection signal at every second ignition pulse, whose generation takes place in the manner described hereinbelow. The ignition signals are fed to a pulse shaper stage whose output signals are fed by way of a frequency divider having the ratio 2 1 to a control multivibrator. This control multivibrator contains a charge storage member which is charged during the pulse duration of the output signal supplied by the frequency divider and the discharging operation of the charge storage member is introduced after the half period of the frequency divider output signal. The timing of this discharging operation is necessarily dependent on the speed. Moreover, the air throughput in the inlet manifold of the internal combustion engine can be used to control the charging and discharging operation.The discharge time represents the basic injection time which can further be corrected in a temperature-or load-dependent manner.
In order to construct the injection system cheaply it has proved advantageous, instead of correlating a separate injection valve with every cylinder, to use a single injection site in the manifold. The fuel required by all the cylinders then has to be prepared at this injection site so that a valve of greater dimensions is accordingly required, since a very high fuel throughput per unit of time then occurs through the injection site. The desired atomisation of the fuel and the mixture formation can thereby be impaired.
In accordance with the present invention, there is provided an electronically controlled fuel injection system which operates with externally controlled ignition, comprising at least one pulse shaper, at least one control multivibrator, at least one correction stage and at least one electromagnetically actuable injection valve which is adapted to inject fuel into the induction manifold of the engine and which receives injection pulses in synchronism with the revolutions of the crankshaft, the length of which pulses is dependent on at least one operating parameter of the internal combustion engine, and wherein an injection pulse is generated for each ignition pulse and is initiated only at the beginning of a discharging period of a charge storing device of the control multivibrator.
The aforegoing arrangement has the advantage that the desired fine atomisation of the fuel can be obtained without the single fuel valve being constructed with substantially greater dimensions.
The invention is described further hereinafter, by way of example, with reference to the accompanying drawings, in which:
Figure 1 shows a control device in accordance with the Prior Art;
Figure 2 is an associated pulse diagram;
Figure 3 shows a first embodiment of a control device for a fuel injection system in accordance with the invention
Figure 4 is an associated pulse diagram;
Figure 5 shows a second embodiment of a control device for a fuel injection system in accordance with the invention;
Figure 6 is an associated pulse diagram; and
Figure 7 shows a control multivibrator.
The known arrangement of Figure 1 includes a series connection of an ignition pulse generator 10, a pulse shaper 11, a frequency divider 12, a control multi-vibrator 13, a multiplier 14 and a valve device 15. Only the main component groups are shown in Figure 1, the air throughput in the air inlet manifold being taken into account in the control multivibrator 13 and individual corrections such as e.g. load, speed or starting boost, being taken into account in the multiplier 14.
In this known control device for electronically controlled fuel injection systems, an injection pulse is generated for every second ignition pulse. The individual pulses in this known control device are shown in Figure 2.
Figure 2a shows the individual ignition pulses with respect to the crankshaft angle in the case of a four-cylinder internal combustion engine wherein the interval between the ignition pulses is in each case 180 . The pulse shaper 11 generates by means of a monostable trigger stage rectangular pulses of a constant period, whose leading edges in each case coincide with the ignition pulses. The frequency of the output signal of the pulse shaper 11 is halved in the frequency divider 12, connected thereto.
This is shown in Figure 2c. The edges of the output signal of the frequency divider 12 coincide with edges of the ignition signals.
The subsequent control multivibrator 13 controls a store which is charged and discharged according to Figure 2d. The charging takes place during the entire period of the frequency divider output pulses, the discharging operations commencing in each case at the trailing edge of the latter pulses. In the known control device the discharge rate is dependent upon the air throughput in the air inlet manifold. After the end of the discharge operation, a resting pause occurs in the store until the leading edge of the next frequency divider output pulse occurs. At the same time, the control multivibrator 13 transposes the period of the discharge operation into a corresponding pulse period, as is shown in Figure 2e.Lastly, this pulse period (tp) is expanded by a correction stage in the multiplier 14 and is made available as a pulse of period tm (Figure 2f) for which the valve device 15 is opened.
In the case of the input signal to the valve device in accordance with Figure 2f, it will be observed that the injection timing begins after every second ignition pulse and maintains a parameter-dependent timing period.
The arrangement of Figure 3 in accordance with the invention is modified in so far as two control multivibrators 20 and 21 as well as a logic gate 22 follow the frequency divider 12.
Output signals of the frequency divider 12 which have in each case been transposed by half a period serve as trigger signals for the two control multivibrators 20 and 21. This is made clear bythe outputs Q and Q of the frequency divider 12.
For the sake of greater clarity, the individual pulse diagrams have been designated by alphabetical letters corresponding to those already used in Figure 2. C again designates the output signal of the frequency divider 12, dl shows the charging operation in the store of the control multivibrator and el its output signal. The corresponding signals d2-and e2 are displaced half a period. The signal sequence f thus results as the output signal of the logic gate 22 which is constructed as an OR gate.
In the control device described above a signal is obtained for each ignition pulse by a simple doubling of the control multivibrator and a triggering, displaced by 180 , at the output of the gate 22.
The same pulse ratio is obtained with the control device of Figure 5 whose pulse diagrams are shown in Figure 6. The control device itself comprises the series connection of an ignition pulse generator 10, a pulse shaper 11, a control multivibrator 25 and a multiplier 14. In so doing, however, an altered charging and discharging of the store in the control multivibrator 25 is required. The method of operation of this control device of Figure 5 is explained with reference to the diagrams in
Figure 6.
Figure 6a shows the ignition pulses of a four-cylinder internal combustion engine with respect to the crankshaft angle. Figure 6b shows the output signal of the pulse shaper stage. The charging and discharging of the store in the control multivibrator now takes place in such a manner that the charging and discharging operations follow one another alternately and continuously without any kind of intermediate phase whatsoever. The discharging operation is thereby introduced at the point in time of each leading edge of the output signal of the pulse shaper 11, at the termination of which operation a fresh charging operation takes place at once. The output signal of the control multivibrator 25 itself is then generated in a known manner and is available as a pulse period during each discharging operation of the store.
An embodiment of the control multivibrator 25, which can also be used in its modified form as a control multivibrator of Figures 1 and 3, is shown in Figure 7.
The main elements of the control multivibrator 25 are a storage capacitor 30, a charging current source 31 as well as a discharging current source 32 and a first switching transistor 33. The series connection of the first switching transistor 33 and the charging current source 31 is connected between a positive line 35 and a negative line 36. The series connection of the storage capacitor 30 and the discharging current source 32 is connected in parallel with the charging current source. The connection point 37 between the source 32 and capacitor 30 is coupled to the base of a transistor 39 whose emitter is connected to the positive line 35 and whose collector is connected by way of a series connection of two resistors 40 and 41 to the negative line 36. The base of a further transistor 42 is coupled to the junction of the two resistors 40 and 41 and its emitter is connected to the negative line 36 whilst its collector leads on the one hand by way of a resistor 44 to the positive line 35 and on the other hand by way of a line 45 to a decoupling element 46 whose output 47 forms the output of the control multivibrator. Finally a voltage divider comprising two resistors 49 and 50, whose junction point is coupled to the base of a transistor 51, is further connected between the line 45 and the negative line 36. This transistor 51 is connected by its emitter to the negative line 36 and by its collector by way of a resistor 53 to a connection point 54 which is further led to the base of the switching transistor 33 and by way of a resistor 55 and a trigger stage 56 to the main input 58 of the control multivibrator.
The discharging current source 32 is shown as a variable current source, e.g. variable in dependence upon the air throughput in the inlet manifold. The dotted lines around the charging current source 31 indicate a possible on-off control circuit which is necessary for the use of the control multivibrator in the control devices in accordance with Figures 1 and 3.
The operation of the control multivibrator in accordance with Figure 7 is as follows.
The starting off point is the charged state of the capacitor 30, which is characterised by the switching transistor 33 being blocked and the transistor 39 being conductive. The conductive transistor 39 causes the transistor 42 to become conducting as well, whereby the potential on the line 45 and thus the output signal of the control multivibrator is kept low.
By means of a negative trigger pulse by way of the input 58 and the trigger stage 56 to the connection point 54, the switching transistor 33 is turned on, whereby the potential at the connection point of the switching transistor 33 and of the charging current source 31 is raised. The storage capacitor 30 transfers this jump potential to the base of the transistor 39 so that it is turned off. The transistor 42 is also turned off as a result of this and the voltage value at the line 45 as well as at the output 47 of the decoupling stage 46 rises. This voltage rise on the line 45 results at the same time in the turning on of the transistor 51, whose collector current also still keeps the switching transistor 33 in its conductive state when the trigger pulse coming from the trigger stage 56 has fallen away again.A positive signal is now connected to the output of the control multivibrator for as long as the transistor 39 is blocked. This timing period is dependent on the discharging current source 32 whose current is made dependent upon the air throughput in the inlet manifold of the internal combustion engine. When the potential at the point 37 has fallen sufficiently due to the capacitor 30 discharging by way of the discharging current source 32, then the transistor 39 again passes into its conducting state, by which means the transistor 42 is likewise turned on and the potential on the line 45 and thus at the output of the control multivibrator again falls.
In using the control multivibrator in the control device in accordance with Figure 5, the charging current source 31 is continuously
switched on. It remains ineffective only for the
time that the switching transistor 33 is turned
on and the current of the discharging current
source 31 is consequently withdrawn by way of
this switching transistor 33 from the positive
line 35. On the other hand the charging current
source 31 when used in the control devices in
accordance with Figures 1 and 3 is controlled
so as to be conducting in a manner which is
dependent as regards timing, on the output signal of the frequency divider 12.
A substantial difference between the control devices in accordance with Figures 3 and 5 is to be found in the fact that in the last analysis the charging of the storage capacitor 30 in the device in accordance with Figure 5 is likewise dependent on the air throughput. This is due to the fact that in every period of the ignition signal the discharging and charging operation of the storage device merge smoothly into each other whilst the charging operation in accordance with the control device of Figure 3 is dependent on the speed signal above. In practical operation, however, this dependence has not shown itself to be a disadvantage.
It is possible by means of the control devices described above to considerably simplify a known injection system, so that only a single injection site is required, at least for a group of cylinders.
As the injection frequency corresponds to the ignition frequency and thus to the pulsation frequency of the air flow in the inlet manifold branches, a substantial advantage of a fuel injection system in accordance with the present invention is that the injection fuel is distributed equally to all the cylinders.
WHAT WE CLAIM IS:
1. An electronically controlled fuel injection system for an internal combustion engine which operates with externally controlled ignition, comprising at least one pulse shaper, at least one control multivibrator, at least one correction stage and at least one electromagnetically actuable injection valve which is adapted to inject fuel into the induction manifold of the engine and which receives injection pulses in synchronism with the revolutions of the crankshaft, the length of which pulses is dependent on at least one operating parameter of the internal combustion engine, and wherein an injection pulse is generated for each ignition pulse and is initiated only at the beginning of a discharging period of a charge storing device of the control multivibrator.
2. An electronically controlled fuel injection system as claimed in claim 1, in which there are two control multivibrators which operate in parallel and whose output signals are displaced by half a period, the outputs of said multivibrators being coupled by way of a logic gate to a subsequent correction stage, and the inputs of said multivibrators being connected to a frequency divider.
3. An electronically controlled fuel injection system as claimed in claim 2, in which the control multivibrators each contain a respective charge storage device, and in which charging of the charge storage devices occurs during the first half-period of the frequency divider output signal, and discharging occurs during the following half period, the charging and/or discharging rate being dependent on said at least one operating characteristic of the internal combustion engine.
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (10)
- **WARNING** start of CLMS field may overlap end of DESC **.56 to the main input 58 of the control multivibrator.The discharging current source 32 is shown as a variable current source, e.g. variable in dependence upon the air throughput in the inlet manifold. The dotted lines around the charging current source 31 indicate a possible on-off control circuit which is necessary for the use of the control multivibrator in the control devices in accordance with Figures 1 and 3.The operation of the control multivibrator in accordance with Figure 7 is as follows.The starting off point is the charged state of the capacitor 30, which is characterised by the switching transistor 33 being blocked and the transistor 39 being conductive. The conductive transistor 39 causes the transistor 42 to become conducting as well, whereby the potential on the line 45 and thus the output signal of the control multivibrator is kept low.By means of a negative trigger pulse by way of the input 58 and the trigger stage 56 to the connection point 54, the switching transistor 33 is turned on, whereby the potential at the connection point of the switching transistor 33 and of the charging current source 31 is raised. The storage capacitor 30 transfers this jump potential to the base of the transistor 39 so that it is turned off. The transistor 42 is also turned off as a result of this and the voltage value at the line 45 as well as at the output 47 of the decoupling stage 46 rises. This voltage rise on the line 45 results at the same time in the turning on of the transistor 51, whose collector current also still keeps the switching transistor 33 in its conductive state when the trigger pulse coming from the trigger stage 56 has fallen away again.A positive signal is now connected to the output of the control multivibrator for as long as the transistor 39 is blocked. This timing period is dependent on the discharging current source 32 whose current is made dependent upon the air throughput in the inlet manifold of the internal combustion engine. When the potential at the point 37 has fallen sufficiently due to the capacitor 30 discharging by way of the discharging current source 32, then the transistor 39 again passes into its conducting state, by which means the transistor 42 is likewise turned on and the potential on the line 45 and thus at the output of the control multivibrator again falls.In using the control multivibrator in the control device in accordance with Figure 5, the charging current source 31 is continuously switched on. It remains ineffective only for the time that the switching transistor 33 is turned on and the current of the discharging current source 31 is consequently withdrawn by way of this switching transistor 33 from the positive line 35. On the other hand the charging current source 31 when used in the control devices in accordance with Figures 1 and 3 is controlled so as to be conducting in a manner which is dependent as regards timing, on the output signal of the frequency divider 12.A substantial difference between the control devices in accordance with Figures 3 and 5 is to be found in the fact that in the last analysis the charging of the storage capacitor 30 in the device in accordance with Figure 5 is likewise dependent on the air throughput. This is due to the fact that in every period of the ignition signal the discharging and charging operation of the storage device merge smoothly into each other whilst the charging operation in accordance with the control device of Figure 3 is dependent on the speed signal above. In practical operation, however, this dependence has not shown itself to be a disadvantage.It is possible by means of the control devices described above to considerably simplify a known injection system, so that only a single injection site is required, at least for a group of cylinders.As the injection frequency corresponds to the ignition frequency and thus to the pulsation frequency of the air flow in the inlet manifold branches, a substantial advantage of a fuel injection system in accordance with the present invention is that the injection fuel is distributed equally to all the cylinders.WHAT WE CLAIM IS: 1. An electronically controlled fuel injection system for an internal combustion engine which operates with externally controlled ignition, comprising at least one pulse shaper, at least one control multivibrator, at least one correction stage and at least one electromagnetically actuable injection valve which is adapted to inject fuel into the induction manifold of the engine and which receives injection pulses in synchronism with the revolutions of the crankshaft, the length of which pulses is dependent on at least one operating parameter of the internal combustion engine, and wherein an injection pulse is generated for each ignition pulse and is initiated only at the beginning of a discharging period of a charge storing device of the control multivibrator.
- 2. An electronically controlled fuel injection system as claimed in claim 1, in which there are two control multivibrators which operate in parallel and whose output signals are displaced by half a period, the outputs of said multivibrators being coupled by way of a logic gate to a subsequent correction stage, and the inputs of said multivibrators being connected to a frequency divider.
- 3. An electronically controlled fuel injection system as claimed in claim 2, in which the control multivibrators each contain a respective charge storage device, and in which charging of the charge storage devices occurs during the first half-period of the frequency divider output signal, and discharging occurs during the following half period, the charging and/or discharging rate being dependent on said at least one operating characteristic of the internal combustion engine.
- 4. An electronically controlled fuel injection system as claimed in claim 3, in which the charging and/or discharging rate of the charge storage devices is dependent upon the air throughput in the inlet manifold of the engine.
- 5. An electronically controlled fuel injection system as claimed in claim 3 or 4, in which the control multivibrators each transmit an output signal during their respective discharging operation.
- 6. An electronically controlled fuel injection system as claimed in claim 1, in which the discharge period of the charge storage device is arranged to commence synchronously with each ignition signal, charging and discharging operations taking place alternately and continuously.
- 7. An electronically controlled fuel injection system as claimed in claim 5, in which the charging and discharging rates of the charge storage device are dependent on an operating characteristic of the internal combustion engine.
- 8. An electronically controlled fuel injection system as claimed in claim 7 in which the charging and discharging rates of the charge storage device are dependent upon the air throughput in the inlet manifold of the engine.
- 9. An electronically controlled fuel injection system substantially as hereinbefore particularly described with reference to and as illustrated in Figures 3 and 4, or in Figures 5 and 6 of the accompanying drawings.
- 10. An electronically controlled fuel inject tion system as claimed in claim 1, having a control multivibrator substantially as hereinbefore particularly described with reference to and as illustrated in Figure 7 of the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19772709187 DE2709187A1 (en) | 1977-03-03 | 1977-03-03 | CONTROL DEVICE FOR AN ELECTRONICALLY CONTROLLED FUEL INJECTION SYSTEM |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1598043A true GB1598043A (en) | 1981-09-16 |
Family
ID=6002661
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB845378A Expired GB1598043A (en) | 1977-03-03 | 1978-03-03 | Electrically controlled fuel injection systems |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS53109025A (en) |
| DE (1) | DE2709187A1 (en) |
| FR (1) | FR2382587A1 (en) |
| GB (1) | GB1598043A (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1119493A (en) * | 1978-07-21 | 1982-03-09 | Mamoru Fujieda | Fuel injection system for internal combustion engine |
| JPS597548Y2 (en) * | 1979-11-15 | 1984-03-08 | 日産自動車株式会社 | Internal combustion engine fuel supply system |
| JPS56118527A (en) * | 1980-02-26 | 1981-09-17 | Japan Electronic Control Syst Co Ltd | Arithmetic unit for fuel injection pulse for electronically controlled fuel injection system |
| US4290394A (en) * | 1980-03-07 | 1981-09-22 | Brunswick Corporation | Two-cycle engine with fuel injection |
| JPS58138235A (en) * | 1982-02-10 | 1983-08-17 | Fuji Heavy Ind Ltd | Fuel injection device of gasoline engine |
| JPS6138139A (en) * | 1984-07-30 | 1986-02-24 | Nippon Denso Co Ltd | Fuel injection control device in internal-combustion engine |
| US5279272A (en) * | 1991-06-19 | 1994-01-18 | Volkswagen Ag | Method and apparatus for controlling fuel injection valves in an internal combustion engine |
| DE4120116A1 (en) * | 1991-06-19 | 1992-12-24 | Volkswagen Ag | METHOD AND ARRANGEMENT FOR GENERATING ACTUATION PULSES FOR FUEL INJECTION VALVES OF AN INTERNAL COMBUSTION ENGINE |
| DE4339175A1 (en) * | 1993-11-16 | 1995-05-18 | Erich Mensing | Prodn. of mouldings and constructional elements used for building applications |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1465052A (en) * | 1973-02-20 | 1977-02-23 | Lucas Electrical Ltd | Fuel control systems |
-
1977
- 1977-03-03 DE DE19772709187 patent/DE2709187A1/en not_active Withdrawn
- 1977-12-15 FR FR7737923A patent/FR2382587A1/en not_active Withdrawn
-
1978
- 1978-03-02 JP JP2402578A patent/JPS53109025A/en active Pending
- 1978-03-03 GB GB845378A patent/GB1598043A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE2709187A1 (en) | 1978-09-07 |
| FR2382587A1 (en) | 1978-09-29 |
| JPS53109025A (en) | 1978-09-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed | ||
| PCNP | Patent ceased through non-payment of renewal fee |