CA1297359C - Method for controlling fuel supply on start of internal combustionengine - Google Patents
Method for controlling fuel supply on start of internal combustionengineInfo
- Publication number
- CA1297359C CA1297359C CA000544192A CA544192A CA1297359C CA 1297359 C CA1297359 C CA 1297359C CA 000544192 A CA000544192 A CA 000544192A CA 544192 A CA544192 A CA 544192A CA 1297359 C CA1297359 C CA 1297359C
- Authority
- CA
- Canada
- Prior art keywords
- fuel
- fuel injection
- engine
- injection valve
- valve
- 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 - Fee Related
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
- F02D41/34—Controlling fuel injection of the low pressure type with means for controlling injection timing or duration
- F02D41/345—Controlling injection timing
-
- 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
- F02D41/04—Introducing corrections for particular operating conditions
- F02D41/06—Introducing corrections for particular operating conditions for engine starting or warming up
- F02D41/062—Introducing corrections for particular operating conditions for engine starting or warming up for starting
-
- 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
- Y02T10/40—Engine management systems
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
Patent ABSTRACT OF THE DISCLOSURE
Described herein is a method for controlling the fuel supply on start of multiple-cylinder internal combustion engines, in which: first and second fuel injection valves are located on the upstream and downstream side, respectively, of the throttle valve located upstream of the junction of the intake pipes of an engine; and a predetermined amount of fuel is injected from the second fuel injection valve on start of the engine while inject-ing fuel from the first fuel injection valve in synchronism with a crank angle signal generated a plural number of times per revolution of the engine crankshaft.
Described herein is a method for controlling the fuel supply on start of multiple-cylinder internal combustion engines, in which: first and second fuel injection valves are located on the upstream and downstream side, respectively, of the throttle valve located upstream of the junction of the intake pipes of an engine; and a predetermined amount of fuel is injected from the second fuel injection valve on start of the engine while inject-ing fuel from the first fuel injection valve in synchronism with a crank angle signal generated a plural number of times per revolution of the engine crankshaft.
Description
1297~S9 Patent METHOD FOR CONTROLLING FUEL SUPPLY ON START OF
INTERNAL COMBUSTION ENGINE
This invention relates to a method for controlling fuel supply during the start of an internal combustion engine, and more particularly to a method for controlling fuel supply during the starting of a multiple-cylinder internal combustion engine by distributing fuel by means of a fuel injection valve located in the intake pipe of the engine.
The conventional fuel supply control system of the type which is arrange to distribute fuel to a plural number of cylinders of an internal combustion engine from a common fuel injection valve is disclosed, for example, in Japanese Laid-Open Patent Application 47-35422, in which under high- and medium-load conditions of the engine the fuel is supplied from a fuel injec-tion valve of a large flow rate located upstream of the throttle valve and under low-load conditions of the engine the fuel is supplied from an auxiliary fuel injection valve located down-tream of the throttle valve. This system uses an auxiliary fuel injection valve of good atomization characteristics to secure distribution of a small amount of fuel to the respective cylinders under low load conditions.
However, when starting an engine at ultra-low temperatures, it is necessary to supply the fuel at a relatively large flow rate since a large amount of the injected fuel deposits on the inner wall surfaces of the intake pipes.
However, it is difficult for the auxiliary fuel injection valve having good atomization characteristics to accomplish the supply of fuel at a large flow rate in a short time period.
Furthermore,-if a fuel injection valve which is capable of large ~2~73~ Patent flow rate fuel supply during engine starting at ultra-low temperatures is used as the auxiliary fuel injection valve, there will be a problem of insufficient atomization of the injected fuel, leading to unsatisfactory fuel distribution to the respective cylinders.
With the foregoing situations in view, the present invention has as its object the provision of a method for controlling the fuel supply during the start of an internal combustion engine, which can ensure good fuel atomization during an engine start over a wide temperature range covering from ultra-low temperature cold engine conditions to normal temperature conditions.
In accordance with the present invention, for achieving the above-mentioned object, there is provided a method Eor controlling the fuel supply during start of a multiple-cylinder internal combustion engine by providing fîrst and second fuel injection valves on the upstream and downstream sides, respectively, of the throttle valve located upstream of the junction of the intake pipe with the intake manifold of the engine, injecting a predetermined amount of fuel from the second fuel injection valve during start of the engine while injecting fuel from said first fuel injection valve in synchronism with a crank angle signal generated for a plural number of times per revolution of the crankshaft of the engine.
The above and other objects, features and advantage of the invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings which show by way of example a preferred embodiment of the invention.
In the accompanying drawings:
~ 359 17~
Fig~ 1 is a diagrammatic illustration showing the general configuration of a fuel supply control system for an internal combustion engine, incorporating the method of the invention;
Fig. 2 is a program flowchart of a during start fuel injection control subroutine executed by the ECU of Fig. l; and Fig. 3 is a timing chart showing the fuel injection characteristics during engine starting according to the method of the invention.
Now, the invention is described more particularly ~y way of a preferred embodiment shown in the drawings.
Referring to Fig. 1, there is shown the general configuration of a fuel supply control system employed for carrying out the method of the invention, in which the reference numeral 1 denotes, for example, a four-cylinder internal combustion engine which is connected to an intake pipe 2 through an intake manifold 2'. A throttle casing 3 which accommodates therein a throttle valve 3' is provided in a position upstream of the junction of the air intake pipe 2 with the intake manifold 2'. The throttle valve 3' is associated with a sensor 4 which is arranged to convert the open angle (8TH) of the throttle valve into an electric signal for supplying to an electronic control unit 5 (hereinafter referred to as "ECU" for ~revity).
Located a little upstream of the throttle casing 3 is a fuel injection valve 6 which supplies fuel to all of the cylinders of the internal combustion engine 1. An auxiliary fuel injection valve 6a is located in a position a little downstream of the throttle casing 3 and upstream of the junction of the intake pipe 2 with the intake manifold 2' to supply fuel to a cylinder which first comes into the intake stroke upon starting ~2~ Pa ~ t the internal combustion engine 1. The fuel injection valve 6 and auxiliary fuel injection valve 6a are connected to a fuel pump, not shown, and at the same time electrically connected to the ECU
5 which controls the valve open time periods of the two fuel injection valves 6 and 6a.
An absolute pressure (P8A) sensor B is provided downstream of the throttle casing 3 through a pipe 7 thereby converting the detected absolute pressure into an electric signal for supply to the ECU 5.
Provided on the engine 1 is an engine cooling water temperature sensor 9 (hereinafter referred to as "TW sensor" for brevity) which consists of a thermistor and other known components and is mounted in a peripheral engine cylinder wall in contact with the engine cooling water to send a signal of the detected cooling water temperature to the ECU S. A crank angle position sensor 10 (hereinafter referred to as "T16 sensor") i5 mounted on the circumference of the camshaft or crankshaft which are not shown, to produce a crank angle position signal (herein-after referred to as "T16 signal") at every g5 revolution of the engine crankshaft at a predetermined crank angle position relative to TDC ("Top Dead Center"~ of each cylinder, sending the Tl~ signal to the ~CU 5. The rate of engine revolutions or engine speed Ne is detected from the frequency of this T16 signal.
Located within the exhaust pipe 11 of the engine 1 is a ternary catalyst 12 to clean the HC, CO and NOx components out of the exhaust gas. An 0~ sensor 13 is fitted in the exhaust pipe 11 at a position upstream of the ternary catalyst 12 to detect the oxygen concentration in the exhaust gas and send an 0 concentration signal to the ECU 5.
179/l24 ~29~35~ Patellt Further, connected to the ECU 5 is a sensor 1~ for any other parameters, for example, the atmospheric pressure, to send a detected signal of such other parameters to the ECU 5.
Ignition switch 15 and starter switch 16 for the engine are connected to the ECU 5 to supply thereto signals indicative of on- and off-states of the ignition and starter switches.
The ECU 5 includes an input circuit 5a which has functions of shaping the waveforms of input signals from various sensors, correcting input signal voltages to predetermined levels, and converting analog signal values into digital signal values, a central processing unit 5b (hereinafter referred to as "CPU"), memory means 5c for storing various arithmetic and logic programs and the results of arith~etic operations, and an output circuit 5d for supplying drive signals to the fuel injection valve 6 and the auxiliary fuel injection valve 6a.
Upon receipt of each T16 signal, the CPU 5b computes the fuel injection time lengths of the injection valve 6 and auxiliary injection valve 6a on the basis of the engine parameter signals which are supplied from various sensors through the input circuit 5a, sending valve opening drive signals based on the computed fuel injection time.
Under control of the CPU Sb, the fuel injection valve 6 and the auxiliary fuel injection valve 6a are operated in the following manner during the start of the internal combustion engine 1. During an engine start, the auxiliary fuel injection vaIve 6a is opened in response to a first T16 signal to inject fuel of well-atomized state only once, and thereafter it is held in a closed state. tsee Fig. 3(c).) The fuel injection valve 6 is also opened upon starting the engine at every four T16 signals when the amount of fuel ~7359 Patent injection "Tout" is of a normal rate (Fig. 3(d')), and opened at each T16 signal when injection of a large amount of fuel is required due to an extremely low engine temperature (Fig.
INTERNAL COMBUSTION ENGINE
This invention relates to a method for controlling fuel supply during the start of an internal combustion engine, and more particularly to a method for controlling fuel supply during the starting of a multiple-cylinder internal combustion engine by distributing fuel by means of a fuel injection valve located in the intake pipe of the engine.
The conventional fuel supply control system of the type which is arrange to distribute fuel to a plural number of cylinders of an internal combustion engine from a common fuel injection valve is disclosed, for example, in Japanese Laid-Open Patent Application 47-35422, in which under high- and medium-load conditions of the engine the fuel is supplied from a fuel injec-tion valve of a large flow rate located upstream of the throttle valve and under low-load conditions of the engine the fuel is supplied from an auxiliary fuel injection valve located down-tream of the throttle valve. This system uses an auxiliary fuel injection valve of good atomization characteristics to secure distribution of a small amount of fuel to the respective cylinders under low load conditions.
However, when starting an engine at ultra-low temperatures, it is necessary to supply the fuel at a relatively large flow rate since a large amount of the injected fuel deposits on the inner wall surfaces of the intake pipes.
However, it is difficult for the auxiliary fuel injection valve having good atomization characteristics to accomplish the supply of fuel at a large flow rate in a short time period.
Furthermore,-if a fuel injection valve which is capable of large ~2~73~ Patent flow rate fuel supply during engine starting at ultra-low temperatures is used as the auxiliary fuel injection valve, there will be a problem of insufficient atomization of the injected fuel, leading to unsatisfactory fuel distribution to the respective cylinders.
With the foregoing situations in view, the present invention has as its object the provision of a method for controlling the fuel supply during the start of an internal combustion engine, which can ensure good fuel atomization during an engine start over a wide temperature range covering from ultra-low temperature cold engine conditions to normal temperature conditions.
In accordance with the present invention, for achieving the above-mentioned object, there is provided a method Eor controlling the fuel supply during start of a multiple-cylinder internal combustion engine by providing fîrst and second fuel injection valves on the upstream and downstream sides, respectively, of the throttle valve located upstream of the junction of the intake pipe with the intake manifold of the engine, injecting a predetermined amount of fuel from the second fuel injection valve during start of the engine while injecting fuel from said first fuel injection valve in synchronism with a crank angle signal generated for a plural number of times per revolution of the crankshaft of the engine.
The above and other objects, features and advantage of the invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings which show by way of example a preferred embodiment of the invention.
In the accompanying drawings:
~ 359 17~
Fig~ 1 is a diagrammatic illustration showing the general configuration of a fuel supply control system for an internal combustion engine, incorporating the method of the invention;
Fig. 2 is a program flowchart of a during start fuel injection control subroutine executed by the ECU of Fig. l; and Fig. 3 is a timing chart showing the fuel injection characteristics during engine starting according to the method of the invention.
Now, the invention is described more particularly ~y way of a preferred embodiment shown in the drawings.
Referring to Fig. 1, there is shown the general configuration of a fuel supply control system employed for carrying out the method of the invention, in which the reference numeral 1 denotes, for example, a four-cylinder internal combustion engine which is connected to an intake pipe 2 through an intake manifold 2'. A throttle casing 3 which accommodates therein a throttle valve 3' is provided in a position upstream of the junction of the air intake pipe 2 with the intake manifold 2'. The throttle valve 3' is associated with a sensor 4 which is arranged to convert the open angle (8TH) of the throttle valve into an electric signal for supplying to an electronic control unit 5 (hereinafter referred to as "ECU" for ~revity).
Located a little upstream of the throttle casing 3 is a fuel injection valve 6 which supplies fuel to all of the cylinders of the internal combustion engine 1. An auxiliary fuel injection valve 6a is located in a position a little downstream of the throttle casing 3 and upstream of the junction of the intake pipe 2 with the intake manifold 2' to supply fuel to a cylinder which first comes into the intake stroke upon starting ~2~ Pa ~ t the internal combustion engine 1. The fuel injection valve 6 and auxiliary fuel injection valve 6a are connected to a fuel pump, not shown, and at the same time electrically connected to the ECU
5 which controls the valve open time periods of the two fuel injection valves 6 and 6a.
An absolute pressure (P8A) sensor B is provided downstream of the throttle casing 3 through a pipe 7 thereby converting the detected absolute pressure into an electric signal for supply to the ECU 5.
Provided on the engine 1 is an engine cooling water temperature sensor 9 (hereinafter referred to as "TW sensor" for brevity) which consists of a thermistor and other known components and is mounted in a peripheral engine cylinder wall in contact with the engine cooling water to send a signal of the detected cooling water temperature to the ECU S. A crank angle position sensor 10 (hereinafter referred to as "T16 sensor") i5 mounted on the circumference of the camshaft or crankshaft which are not shown, to produce a crank angle position signal (herein-after referred to as "T16 signal") at every g5 revolution of the engine crankshaft at a predetermined crank angle position relative to TDC ("Top Dead Center"~ of each cylinder, sending the Tl~ signal to the ~CU 5. The rate of engine revolutions or engine speed Ne is detected from the frequency of this T16 signal.
Located within the exhaust pipe 11 of the engine 1 is a ternary catalyst 12 to clean the HC, CO and NOx components out of the exhaust gas. An 0~ sensor 13 is fitted in the exhaust pipe 11 at a position upstream of the ternary catalyst 12 to detect the oxygen concentration in the exhaust gas and send an 0 concentration signal to the ECU 5.
179/l24 ~29~35~ Patellt Further, connected to the ECU 5 is a sensor 1~ for any other parameters, for example, the atmospheric pressure, to send a detected signal of such other parameters to the ECU 5.
Ignition switch 15 and starter switch 16 for the engine are connected to the ECU 5 to supply thereto signals indicative of on- and off-states of the ignition and starter switches.
The ECU 5 includes an input circuit 5a which has functions of shaping the waveforms of input signals from various sensors, correcting input signal voltages to predetermined levels, and converting analog signal values into digital signal values, a central processing unit 5b (hereinafter referred to as "CPU"), memory means 5c for storing various arithmetic and logic programs and the results of arith~etic operations, and an output circuit 5d for supplying drive signals to the fuel injection valve 6 and the auxiliary fuel injection valve 6a.
Upon receipt of each T16 signal, the CPU 5b computes the fuel injection time lengths of the injection valve 6 and auxiliary injection valve 6a on the basis of the engine parameter signals which are supplied from various sensors through the input circuit 5a, sending valve opening drive signals based on the computed fuel injection time.
Under control of the CPU Sb, the fuel injection valve 6 and the auxiliary fuel injection valve 6a are operated in the following manner during the start of the internal combustion engine 1. During an engine start, the auxiliary fuel injection vaIve 6a is opened in response to a first T16 signal to inject fuel of well-atomized state only once, and thereafter it is held in a closed state. tsee Fig. 3(c).) The fuel injection valve 6 is also opened upon starting the engine at every four T16 signals when the amount of fuel ~7359 Patent injection "Tout" is of a normal rate (Fig. 3(d')), and opened at each T16 signal when injection of a large amount of fuel is required due to an extremely low engine temperature (Fig.
3(d)). Thus, the injection of a large amount of fuel is effected by a plural number of separate iniections of small amounts (four small injections in this case) per revolution of the crankshaft to ensure good fuel atomization.
The procedures of the fuel supply control during an engine start, as in the above-described cases, are explained below more particularly.
Referring to Fig. 2, there is shown a program flowchart of an engine start fuel injection control subroutine which is executed by the CPU Sb in synchronism with the T16 signal which is generated at every 45 of revolution of the crankshaft (Figs.
3(a) and 3(b)).
Firstly in Step 1, whether or not the engine is in the cranking stage, namely, whether or not the number of engine revolutions Ne is smaller than a predetermined number of cranking revolutions is checked. If the answer is negative (no), the engine is regarded as having already been started, and therefore this program- i5 ended without proceeding to Step 2 and onwards.
If the result of discernment in Step 1 is affirmative (ye~), whether or not the starter switch (ST SW) is on-state immediately after resetting of the ECU is checked in next Step 2. If the answer is negative (no3, a check is made in Step 3 as to whether or not the current loop is of the first T16 signal (a crank pulse) which is generated after turning on the ignition switch to commence the start action. If the answer is affirmative (yes), a standard valve open time Tic~a of the auxiliary fuel injection valve 6a according to the engine water Patent ~ 29'735~
temperature Tw is fetched from a table to compute the valve open time Tou~ a of the auxiliary fuel injection valve on the basis of the Tic a value. (Step 4) if the answer in Step 3 is negative (no), the valve open time Tou~a of the auxiliary fuel injection valve is regarded as zero to inhibit the fuel injection from the auxiliary fuel injection valve. (Step 5) Accordingly, the fuel is injected from the auxiliary fuel injection valve only once when the first T16 signal is generated after the engine has commenced its starting action. After this single shot, it never injects fuel again unless the ECU is reset by turning off the ignition switch. (See Fig. 3(c)). If the answer in Step 2 is affirmative ~yes), namely, if the starter switch is still or immediately after resetting of the ECU, the processing goes directly to Step 5, skipping Step 3. Consequently, in the engine start mode when the ECU is re-actuated after its operation is once stopped by a drop in the battery output as a result of the starter operation, until the battery output rises again by the increase of the engine speed accompanied by the increase of the generator rotation, the fuel is not injected from the auxiliary fuel injection valve 6at although the fuel has been injected therefrom by execution of Steps 3 and 4 before the stop of the ECU operation.
In next Step 6, a standard valve open time TicRM of the fuel injection valve 6 according to the engine cooling water temperature Tw is fetched from a table to compute the valve open time Tou~ for the fuel injection valve 6 on the basis of the value of TicR~. Nextly, whether or not this value of TouTM is greater than a predetermined value Toutc~ (e.g., 12 msec) is checked in Step 7, and, if the answer is affirmative (yes), the required amount of fuel injection (TouT~ ) which is necessary for Patent ~-2~'735~
one stroke of a cylinder is divided into four separate shots to accelerate fuel atomization, each time injecting 1/4 of that required amount on generation of a T16 signal (crank pulse).
(Step 8) The valve open time Tou~ of the fuel injection valve 6 on each crank pulse generation is expressed by the following equation (1).
Tou~ = 1/4 x (Tic~ x ~) + Tv~ ................. (1) where TicR~ is the standard valve open time according to the afore-mentioned value of Tw, K is a correction coefficient for correcting the standard valve open time TicR~ according to the detection signals from various sensors except the Tw sensor~ and Tv~ is a correction value for correcting the value of Tou~
according to variations in the battery output and the like.
In case the result of discernment in Step 7 is negative (no), the amount of fuel (TouJ~ ) necessary for one stroke of a cylinder is small, so that, if it is divided into four equivalent portions, each valve open time becomes extremely short beyond the limit of response of the fuel injection valve 6, resulting in inaccurate fuel injection. Therefore, according to the valve open time Tou~ computed in Step 6, it is injected at every four crank pulses, namely, once for one stroke of each cylinder.
(Step ~.
In the final Step 10, a valve open drive signal according to the valve open time Tou~ a, as set in Step 4 or 5, is sent to the auxiliary fuel injection valve (though no drive signal is sent when Tour~ = O a by execution of Step 5).
As is clear from the foregoing description, according to the method of the invention for controlling the fuel supply during the start oE a multiple-cylinder internal combustion engine, first and second fuel injection valves are located _~ _ 17')/~21 Pat~n[
3~i9 upstream and downstream of a throttle valve on the upstream side of the junction of intake pipe with the intake manifold of the engine, respectively, injecting a predetermined amount of fuel from the second fuel injection valve during the start of the engine while injecting fuel from the first fuel injection valve in synchronism with a crank angle signal generated for a plural number of times per revolution of the engine crankshaft, thereby optimizing the fuel atomization during starting of the engine over a wide temperature range from ultra-low engine temperature to normal temperature.
,i ~
' _g_
The procedures of the fuel supply control during an engine start, as in the above-described cases, are explained below more particularly.
Referring to Fig. 2, there is shown a program flowchart of an engine start fuel injection control subroutine which is executed by the CPU Sb in synchronism with the T16 signal which is generated at every 45 of revolution of the crankshaft (Figs.
3(a) and 3(b)).
Firstly in Step 1, whether or not the engine is in the cranking stage, namely, whether or not the number of engine revolutions Ne is smaller than a predetermined number of cranking revolutions is checked. If the answer is negative (no), the engine is regarded as having already been started, and therefore this program- i5 ended without proceeding to Step 2 and onwards.
If the result of discernment in Step 1 is affirmative (ye~), whether or not the starter switch (ST SW) is on-state immediately after resetting of the ECU is checked in next Step 2. If the answer is negative (no3, a check is made in Step 3 as to whether or not the current loop is of the first T16 signal (a crank pulse) which is generated after turning on the ignition switch to commence the start action. If the answer is affirmative (yes), a standard valve open time Tic~a of the auxiliary fuel injection valve 6a according to the engine water Patent ~ 29'735~
temperature Tw is fetched from a table to compute the valve open time Tou~ a of the auxiliary fuel injection valve on the basis of the Tic a value. (Step 4) if the answer in Step 3 is negative (no), the valve open time Tou~a of the auxiliary fuel injection valve is regarded as zero to inhibit the fuel injection from the auxiliary fuel injection valve. (Step 5) Accordingly, the fuel is injected from the auxiliary fuel injection valve only once when the first T16 signal is generated after the engine has commenced its starting action. After this single shot, it never injects fuel again unless the ECU is reset by turning off the ignition switch. (See Fig. 3(c)). If the answer in Step 2 is affirmative ~yes), namely, if the starter switch is still or immediately after resetting of the ECU, the processing goes directly to Step 5, skipping Step 3. Consequently, in the engine start mode when the ECU is re-actuated after its operation is once stopped by a drop in the battery output as a result of the starter operation, until the battery output rises again by the increase of the engine speed accompanied by the increase of the generator rotation, the fuel is not injected from the auxiliary fuel injection valve 6at although the fuel has been injected therefrom by execution of Steps 3 and 4 before the stop of the ECU operation.
In next Step 6, a standard valve open time TicRM of the fuel injection valve 6 according to the engine cooling water temperature Tw is fetched from a table to compute the valve open time Tou~ for the fuel injection valve 6 on the basis of the value of TicR~. Nextly, whether or not this value of TouTM is greater than a predetermined value Toutc~ (e.g., 12 msec) is checked in Step 7, and, if the answer is affirmative (yes), the required amount of fuel injection (TouT~ ) which is necessary for Patent ~-2~'735~
one stroke of a cylinder is divided into four separate shots to accelerate fuel atomization, each time injecting 1/4 of that required amount on generation of a T16 signal (crank pulse).
(Step 8) The valve open time Tou~ of the fuel injection valve 6 on each crank pulse generation is expressed by the following equation (1).
Tou~ = 1/4 x (Tic~ x ~) + Tv~ ................. (1) where TicR~ is the standard valve open time according to the afore-mentioned value of Tw, K is a correction coefficient for correcting the standard valve open time TicR~ according to the detection signals from various sensors except the Tw sensor~ and Tv~ is a correction value for correcting the value of Tou~
according to variations in the battery output and the like.
In case the result of discernment in Step 7 is negative (no), the amount of fuel (TouJ~ ) necessary for one stroke of a cylinder is small, so that, if it is divided into four equivalent portions, each valve open time becomes extremely short beyond the limit of response of the fuel injection valve 6, resulting in inaccurate fuel injection. Therefore, according to the valve open time Tou~ computed in Step 6, it is injected at every four crank pulses, namely, once for one stroke of each cylinder.
(Step ~.
In the final Step 10, a valve open drive signal according to the valve open time Tou~ a, as set in Step 4 or 5, is sent to the auxiliary fuel injection valve (though no drive signal is sent when Tour~ = O a by execution of Step 5).
As is clear from the foregoing description, according to the method of the invention for controlling the fuel supply during the start oE a multiple-cylinder internal combustion engine, first and second fuel injection valves are located _~ _ 17')/~21 Pat~n[
3~i9 upstream and downstream of a throttle valve on the upstream side of the junction of intake pipe with the intake manifold of the engine, respectively, injecting a predetermined amount of fuel from the second fuel injection valve during the start of the engine while injecting fuel from the first fuel injection valve in synchronism with a crank angle signal generated for a plural number of times per revolution of the engine crankshaft, thereby optimizing the fuel atomization during starting of the engine over a wide temperature range from ultra-low engine temperature to normal temperature.
,i ~
' _g_
Claims (2)
1. A method of controlling the fuel supply during the start of a multiple-cylinder internal combustion engine having an intake pipe with a throttle valve and connected to an intake manifold, said method comprising:
providing first and second fuel injection valves upstream and downstream of the throttle valve located on the upstream side of the intake pipe junction with the intake manifold of the engine; and injecting a predetermined amount of fuel from said second fuel injection valve during the start of said engine, while injecting fuel from said first fuel injection valve in synchronism with crank angle signals generated for a plural number of times per revolution of the engine crankshaft.
providing first and second fuel injection valves upstream and downstream of the throttle valve located on the upstream side of the intake pipe junction with the intake manifold of the engine; and injecting a predetermined amount of fuel from said second fuel injection valve during the start of said engine, while injecting fuel from said first fuel injection valve in synchronism with crank angle signals generated for a plural number of times per revolution of the engine crankshaft.
2. The method of claim 1, wherein the frequency of the fuel injection by said first fuel injection valve in synchronism with said crank angle signal is varied according to the valve open time thereof.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61189175A JPS6345447A (en) | 1986-08-12 | 1986-08-12 | Starting fuel supply control method for internal combustion engine |
| JPP61-189175 | 1986-08-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1297359C true CA1297359C (en) | 1992-03-17 |
Family
ID=16236739
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000544192A Expired - Fee Related CA1297359C (en) | 1986-08-12 | 1987-08-11 | Method for controlling fuel supply on start of internal combustionengine |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS6345447A (en) |
| CA (1) | CA1297359C (en) |
| DE (1) | DE3726873A1 (en) |
-
1986
- 1986-08-12 JP JP61189175A patent/JPS6345447A/en active Pending
-
1987
- 1987-08-11 CA CA000544192A patent/CA1297359C/en not_active Expired - Fee Related
- 1987-08-12 DE DE19873726873 patent/DE3726873A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| DE3726873C2 (en) | 1991-05-29 |
| JPS6345447A (en) | 1988-02-26 |
| DE3726873A1 (en) | 1988-03-10 |
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