JPH0988673A - Start fuel feed control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a starting property by estimating the fuel pressure build-up time based on at least one of the detected engine temperature and engine environmental temperature, and controlling the fuel feed when an engine is started in response to the estimated fuel pressure build-up time. SOLUTION: The start time fuel injection timing is set (S101). Whether the read engine water temperature and the relation between the engine water temperature and the intake air temperature satisfy the conditions set in advance or not is judged, and whether the stop period of an engine before a start is long or short is judged based on the judged result (S102). When it is judged that the stop period of the engine is long, i.e., the fuel pressure is almost released, the build-up time required for the fuel pressure to reach the prescribed value after the on-signal of an ignition switch is calculated based on the engine water temperature and intake air temperature (S103). A flag Fl is set to '1' to specify that a judgment is required on whether the build-up of the fuel pressure is in time for the set start time fuel injection timing or not (S104).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starting fuel supply control device for an internal combustion engine, and more particularly to a starting fuel supply control for performing a starting fuel supply control in consideration of a state in which the internal combustion engine is stopped and started. Regarding the control device.

[0002]

2. Description of the Related Art In order to improve the startability of an internal combustion engine,
There is known a device that detects a cooling water temperature before starting the engine and, when the cooling water temperature exceeds a predetermined value, controls so as to increase the fuel injection amount at the time of starting (JP-A-59-13433).
No. 5).

Further, the elapsed time from the stop of the internal combustion engine to the start of the engine is calculated, and the relationship between the measured elapsed time and the fuel temperature is used to calculate the fuel supply amount according to the fuel temperature from the calculated elapsed time. There is known a device (Japanese Patent Laid-Open No. 62-131938) that sets an increase correction amount and increases the fuel supply amount at the time of start based on the set increase correction amount.

[0004]

However, in the former apparatus disclosed in Japanese Patent Laid-Open No. 59-134335, the state during the engine stop period from the engine stop to the start (for example,
Since the correlation between the changing state of the cooling water temperature and the changing state of the fuel temperature changes according to the period length and the place where the cooling water is left), it is only necessary to judge whether or not the detected cooling water temperature exceeds a predetermined value. The change in the correlation cannot be taken into consideration, and the startability cannot be sufficiently improved.

Further, in the latter device disclosed in Japanese Patent Laid-Open No. 61-121938, since the rise time of the fuel pressure which changes depending on the fuel temperature is not taken into consideration, the fuel injection is performed in a state where the fuel pressure does not rise sufficiently. As in the case of the above device, the startability cannot be sufficiently improved, and the start from the ignition switch on operation to the starter operation is extremely short (hereinafter,
The startability at the time of (immediate start) decreases.

The present invention has been made in view of this point, and an object of the present invention is to provide a fuel supply control device for an internal combustion engine capable of sufficiently improving startability.

[0007]

In order to achieve the above object, the invention according to claim 1 provides a fuel injection means for injecting fuel into an intake passage of an internal combustion engine, and a pressure of the fuel supplied to the fuel injection means. A starting fuel supply control device for an internal combustion engine, comprising: a fuel pressure adjusting means for adjusting the fuel pressure to a predetermined value; and a fuel supply controlling means for controlling fuel supply to the engine. Of temperature detection means for detecting at least one of the following, and until the pressure of the fuel supplied to the fuel injection means reaches the predetermined value from the time of starting the engine based on at least one of the detected engine temperature and engine environment temperature. And a time estimation means for estimating the fuel pressure rise time of the engine, the fuel supply control means controlling the fuel supply at the time of starting the engine according to the estimated fuel pressure rise time. The features.

According to a second aspect of the present invention, in the internal combustion engine starting fuel supply control device according to the first aspect, the engine temperature is an engine cooling water temperature.

According to a third aspect of the present invention, in the internal combustion engine starting fuel supply control device according to the first aspect, the engine ambient temperature is an engine intake air temperature.

According to a fourth aspect of the present invention, in the internal combustion engine startup fuel supply control device according to any one of the first to third aspects, the fuel supply control means is responsive to the estimated fuel pressure rise time. It is characterized in that execution of fuel injection by the fuel injection means is delayed.

According to a fifth aspect of the present invention, in the internal combustion engine startup fuel supply control device according to any one of the first to third aspects, the fuel supply control means is responsive to the estimated fuel pressure rise time. It is characterized in that the fuel injection means is caused to execute additional fuel injection.

According to a sixth aspect of the present invention, in the internal combustion engine startup fuel supply control device according to any one of the first to third aspects, the fuel supply control means is responsive to the estimated fuel pressure rise time. It is characterized in that the valve opening time of the fuel injection means is increased.

According to another aspect of the present invention, there is provided an internal combustion engine startup fuel supply control device, which detects at least one of an engine temperature and an engine environment temperature at the time of starting the engine, and uses at least one of the detected engine temperature and engine environment temperature. Based on this, the fuel pressure rise time from the start of the engine until the pressure of the fuel supplied to the fuel injection means reaches a predetermined value is estimated, and the fuel supply at the engine start is controlled according to the estimated fuel pressure rise time. The fuel supply control at the time of starting can be performed in consideration of the fuel rise time that changes depending on the fuel temperature, and the startability can be sufficiently improved.

In the fuel supply control device for starting the internal combustion engine according to the second aspect, the engine cooling water temperature can be used as the engine temperature.

In the fuel supply control device for starting the internal combustion engine according to the third aspect, the engine intake air temperature can be used as the engine environmental temperature.

In the internal combustion engine starting fuel supply control device according to the present invention, the execution of the fuel injection by the fuel injection means is delayed according to the estimated fuel pressure rise time, so that the fuel injection with a predetermined fuel pressure is ensured. Can do the action,
It is possible to improve startability, particularly immediate startability.

In the fuel supply control device for starting the internal combustion engine according to the present invention, the additional fuel injection is executed by the fuel injection means in accordance with the estimated fuel pressure rise time. Is increased, and startability including immediate startability can be improved.

In the fuel supply control device for starting the internal combustion engine according to the present invention, the valve opening time of the fuel injection means is increased according to the estimated rise time of the fuel pressure. The amount of fuel is increased, and startability including immediate startability can be improved.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is an overall configuration diagram showing a control device including a start-time fuel supply control device for an internal combustion engine (hereinafter referred to as an engine) according to a first embodiment of the present invention.

A throttle valve 3 is provided in the middle of an intake pipe 2 connected to an intake port of the engine 1, and a throttle valve opening (θTH) sensor 4 is connected to the throttle valve 3. The θTH sensor 4 outputs an electric signal according to the opening degree of the throttle valve 3, and the electric signal is supplied to an electronic control unit (hereinafter referred to as ECU) 5.

A fuel injection valve 6 is provided for each cylinder between the engine 1 and the throttle valve 3 and slightly upstream of the intake valve (not shown) in the intake pipe 2. Fuel is supplied to each fuel injection valve 6 from a fuel pump (not shown) via a fuel supply pipe 21 and a pressure regulator 22,
The pressure regulator 22 adjusts the pressure of the fuel supplied to the fuel injection valve 6 to a predetermined value with a diaphragm whose back pressure is the pressure in the intake pipe 2 taken in via the pipe 23, and also returns excess fuel to the return pipe 24. Via a fuel tank (not shown). The fuel injection valve 6 is electrically connected to the ECU 5, and the fuel injection amount of each fuel injection valve 6 is controlled by a signal from the ECU 5. The fuel injection amount of each fuel injection valve 6 is represented by the fuel injection time of the fuel injection valve 6, that is, the valve opening time.

A pipe 7 is provided downstream of the throttle valve 3 of the intake pipe 2.
An absolute pressure (PBA) sensor 8 is provided via the.
The PBA sensor 8 is electrically connected to the ECU 5,
The absolute pressure PBA in the intake pipe 2 detected by the sensor 8 is converted into an electric signal and supplied to the ECU 5.

An intake air temperature (TA) sensor 9 is attached to the wall of the intake pipe 2 downstream of the PBA sensor 8, and the intake air temperature (hereinafter referred to as intake air temperature) TA detected by the TA sensor 9 is an electric signal. And is supplied to the ECU 5.

An engine water temperature (TW) sensor 10 composed of a thermistor or the like is attached to the peripheral wall of the cylinder filled with cooling water in the cylinder block of the engine 1, and the engine water temperature (cooling water temperature) detected by the TW sensor 10 is inserted. The TW is converted into an electric signal and supplied to the ECU 5.

A crank angle position (CRK) sensor 12 and a cylinder discriminating (CYL) sensor 13 are mounted around a cam shaft or a crank shaft (not shown) of the engine 1. The CRK sensor 12 is one of the crankshafts of the engine 1.
The CYL sensor 13 outputs a signal pulse (hereinafter, referred to as a CRK signal pulse) at a predetermined crank angle position with a constant crank angle cycle (for example, 30 degree cycle) shorter than 1/2 rotation (180 degrees). A signal pulse (hereinafter referred to as a CYL signal pulse) is output at a predetermined crank angle position of. The CRK signal pulse and the CYL signal pulse are supplied to the ECU 5.

Specifically, the CRK signal pulse output from the CRK sensor 12 is, for example, 24 pulses at equal intervals during two revolutions of the crankshaft with reference to the piston top dead center of each cylinder, that is, for example, The ECU 5 includes a pulse train signal that generates pulses at a crank angle cycle of 30 °.
Generates a TDC discrimination signal for the CRK signal pulse generated at the piston top dead center of each cylinder. That is, TD
The C discrimination signal represents the reference crank angle position of each cylinder and is generated every 180 ° rotation of the crankshaft.
In addition, the ECU 5 calculates the CRME value by measuring the generation time interval of the CRK signal pulse, and further adds the CRME value over the generation time interval of the TDC discrimination signal to obtain the MEME.
Value is calculated and the engine speed NE, which is the reciprocal of the ME value, is calculated.
Is calculated.

A spark plug 19 is provided in each cylinder of the engine 1. The spark plug 19 is the distributor 1.
It is electrically connected to the ECU 5 through 8, and the ignition timing by the ignition plug 19 is controlled by the ECU 5.

An exhaust pipe 14 is connected to the exhaust port of the engine 1. HC in the exhaust gas,
A three-way catalyst 15 for purifying CO, NOx, etc. is provided.

An oxygen concentration sensor (hereinafter referred to as an O 2 sensor) 16 is provided on the exhaust pipe 14 upstream of the three-way catalyst device 15. The O2 sensor 16 outputs an electric signal according to the oxygen concentration in the exhaust gas, and the electric signal is supplied to the ECU 5.

The engine 1 is started by driving the crank shaft of the starter 26, and the driving of the starter 26 is started at substantially the same time as the output of the start signal by the operation of the ignition switch 25 from the ON position to the start position. When the starter 26 starts driving, a starter signal indicating the start of driving is supplied to the ECU 5. Further, the ON signal and the start signal at the ON position of the ignition switch 25 are supplied to the ECU 5.

The ECU 5 is further provided with a battery voltage VB
A battery voltage (VB) sensor 27 that detects the voltage is connected, and the detection signal of the VB sensor 27 is supplied to the ECU 5.

The ECU 5 shapes the input signal waveforms from the above-mentioned various sensors to correct the voltage level to a predetermined level,
An input circuit 5a having a function of converting an analog signal value into a digital signal value, a central processing circuit (hereinafter, CPU)
5b, a storage means 5c for storing various calculation programs executed by the CPU 5b and calculation results, an output circuit 5d for supplying a drive signal to the fuel injection valve 6 and the ignition plug 17, and the like.

Next, the fuel supply control at the time of starting will be described.

When the engine 1 is started, the ignition switch 25 is first operated to the ON position, and an ON signal is output in accordance with the operation to the ON position. The output of this ON signal starts the fuel pump, and the supply of fuel to the fuel supply system (including the pressure regulator 22) to the fuel injection valve 6 is started.

Next, when the ignition switch 25 is operated from the ON position to the start position,
The start signal is output. Ignition switch 25
The starter 26 starts to be driven in accordance with the output of the start signal, and cranking is started.

On the other hand, when the ECU 5 receives the ON signal of the ignition switch 24, the ECU 5 starts reading the data necessary for determining the fuel injection condition used for the fuel supply control at the start, and the engine water temperature TW in the ignition timing control. The ignition advance angle is selected according to. Next, when the starter signal of the starter 26 is input, the starting fuel supply control and the ignition timing control are executed.

The fuel supply control at the time of starting will be described with reference to FIG. FIG. 2 is a flow chart showing a fuel injection control at startup which is executed by the control device of FIG.

Referring to FIG. 2, first, in step S11, it is determined whether or not the ON signal of the ignition switch 25 is input. If it is determined that the ON signal of the ignition switch 25 is input, the process proceeds to step S12.

In step S12, the engine water temperature TW and the intake air temperature TA are read, and in the following step S13,
Whether the starter signal is input from the starter 26 in response to the input of the start signal of the ignition switch 25 is determined.

When it is determined that the starter signal is input from the starter 26, the process proceeds to step S14, and the starting fuel injection condition determination process is executed in step S14. In this startup fuel injection condition determination processing, as will be described later,
Fuel injection time (valve opening time) TOU at the time of starting the fuel injection valve 6
Data for setting the T, determining the soak state for determining whether the stop period before starting the engine 1 is long or short, and determining the fuel injection timing at startup according to the determination result of the soak state (fuel injection The fuel pressure rise time in the fuel supply system to the valve 6 is calculated.

Then, step S15 is executed. In step S15, as will be described later, the starting fuel injection timing is set according to the data calculated in the starting fuel injection condition determination processing in step S14, and when the set starting fuel injection timing arrives, the ECU 5 A drive signal is supplied to the fuel injection valve 6 to start the fuel injection operation, and step 1
Fuel injection is performed during the fuel injection time TOUT at the time of start calculated in 4.

Next, the above-mentioned fuel injection condition determination processing at the start (step S14) will be described with reference to FIGS. 3 is a flowchart showing the fuel injection condition determination process at the time of start of FIG. 2, FIG. 4 is a diagram showing temporal changes of the engine water temperature and the intake air temperature after the engine is stopped, and FIG. 5 is a fuel injection condition at the time of start of FIG. FIG. 6 is a time chart showing the relationship between the rise of the fuel pressure and the fuel injection timing at startup in the determination processing, and FIG. 6 is a diagram showing the fuel pressure rise time table used in the fuel injection condition determination processing at startup in FIG.

Referring to FIG. 3, first, step S101.
The fuel injection condition setting process at startup is executed. In this startup fuel injection condition setting process, for example, the engine water temperature TW,
The intake air temperature TA and the battery voltage VB are read, the starting basic fuel injection time TST preset according to the engine water temperature TW is searched from the starting basic fuel injection table, and the battery voltage VB is set to the basic fuel injection time TST at the starting time. The starting fuel injection time TOUT is calculated by adding the ineffective injection time that changes according to the above. In addition, each fuel injection valve 6
The fuel injection timing at startup, which is the time when the fuel injection is started, is set when the CRK signal pulse is generated after the 1TDC determination signal is generated from the cranking start time (FIG. 8A).
Shown).

Next, in step S102, it is determined whether or not the engine water temperature TW read in step S12 and the relationship between the engine water temperature TW and the intake air temperature TA satisfy preset conditions. Judging the soak state (abandoned state) of the engine 1 based on the result,
That is, it is determined whether the stop period (leave period) of the engine 1 before starting the start is long or short. This determination is to determine whether or not the fuel pressure (fuel pressure) in the fuel supply system to the fuel injection valve 6 is almost released (for example, the fuel pressure is released to a value near 0 kg / cm2). belongs to.

Specifically, the engine water temperature TW and the intake air temperature T
The conditions are set such that the difference from A is ± 5 ° C and the engine water temperature TW is equal to or lower than a predetermined temperature, for example, 50 ° C or less, and the engine water temperature TW read in step S11 and the engine water temperature TW and the intake air temperature TA When the above condition satisfies the above condition, it is determined that the engine 1 is stopped for a long time to the extent that the fuel pressure is almost released. When the above condition is not satisfied, the fuel pressure can still be maintained. It is determined that the stop period of the engine 1 is quite short. As shown in FIG. 4, this condition is based on the relationship between the engine water temperature TW and the intake air temperature TA, which is measured in advance so that the fuel pressure state can be predicted, from the time the engine 1 is stopped to the time it is started. It is set. Further, the engine water temperature TW of 50 ° C. or less under the above conditions is set as the maximum temperature at which it is possible to determine that the engine water temperature TW is stopped for a long period except when the engine water temperature TW is high.

If it is determined in step S102 that the engine 1 has been stopped for a long period of time, that is, the fuel pressure is almost released, the process proceeds to step S103. In step S103, as shown in FIG. 5, based on the engine water temperature TW and the intake air temperature TA read in step S12, the fuel pressure is a predetermined value P from the time when the ON signal of the ignition switch 25 is output.
The rise time TFPR until reaching FATH (for example, 2 kg / cm 2) is calculated. Specifically, a preset gas temperature table in the fuel supply system (not shown)
From step S11, the gas temperature in the fuel supply system to the fuel injection valve 6 corresponding to the engine water temperature TW and the intake air temperature TA read from step S11 is read, and the fuel pressure rise time TFPR corresponding to the read gas temperature is set to the fuel pressure rise time table. Read from. This fuel pressure rise time TFPR is shown in FIG.
As shown in, it is used to determine whether or not the rise of the fuel pressure in the fuel injection control described later is in time for the fuel injection timing at startup set in step S101.

As shown in FIG. 6, in the fuel pressure rising time table, the fuel pressure rising time TFPR is written with respect to the gas temperature in the fuel supply system to the fuel injection valve 6, and the gas temperature is high when the temperature is equal to or higher than the predetermined gas temperature. As it becomes, the fuel pressure rise time T
It can be seen that the FPR becomes longer.

In the following step 104, the flag FI is set to "1" to specify that it is necessary to judge whether or not the rise of the fuel pressure is in time for the fuel injection timing at the time of start set in step S101.

On the other hand, when it is determined in step S102 that the engine 1 stop period is short, step S105
Then, the flag FI is set to "0" to specify that it is not necessary to determine whether the rising of the fuel pressure is in time for the fuel injection timing at startup set in step S101.

Next, the above-mentioned fuel injection control (step S1
5) will be described with reference to FIGS. 7 and 8.
7 is a flowchart showing the fuel injection control of FIG. 2, FIG.
8 is a timing chart showing the fuel injection timing at start and the fuel injection time at start determined by the fuel injection control of FIG. 7.

Referring to FIG. 7, first, step S201.
Then, the CRK signal pulse and the TDC discrimination signal are monitored, and the fuel injection timing at the start, that is, the CRK after the 1TDC discrimination signal is generated.
The arrival of the signal pulse is determined.

When it is determined that the fuel injection timing for starting has arrived, it is determined in step S202 whether the flag F1 is set to "1". If the flag F1 is set to "1", it is determined that it is necessary to determine whether or not the rise of the fuel pressure is in time for the fuel injection timing at startup set in step S101, and the process proceeds to step S203.

In step S203, it is determined whether the time TISTA from the output of the ON signal of the ignition switch 25 to the current time (fuel injection timing) is longer than the fuel pressure rising time TPFR calculated in step S103. If the time TISTA is longer than the fuel pressure rise time TPFR calculated in step S103, it is determined that the fuel pressure has reached the predetermined value PFATH at the current fuel injection timing, and the drive signal is supplied to the fuel injection valve 6 in step S204 to supply the fuel. The injection operation is started, and the fuel is injected for the startup fuel injection time TOUT calculated in step 101.
That is, as shown in FIG. 8A, at the time of generation of the CRK signal pulse after the generation of the 1TDC determination signal, the fuel injection valve 6 performs the fuel injection for the startup fuel injection time TOUT.

On the other hand, in step S203, the time TI
The fuel pressure rise time T calculated by the STA in step S103
When it is determined that it is shorter than PFR, it is determined that the fuel pressure has not reached the predetermined value PFATH at the current fuel injection timing, and fuel injection by the fuel injection valve 6 is performed at the time when the CRK signal pulse is generated after the 1TDC determination signal is generated. Without
It waits for the arrival of the next fuel injection timing (step S201).

At the next fuel injection timing, that is, at the time of generation of the CRK signal pulse after the generation of the 2TDC discrimination signal, the time TISTA from the time when the ON signal of the ignition switch 25 is output to the current time (fuel injection time) is step S1.
If it is determined that the fuel pressure rise time TPFR calculated in step 03 is longer (step S203), the fuel pressure is set to the predetermined value PFAT.
It is determined that the fuel injection time has reached H, the drive signal is supplied to the fuel injection valve 6 to start the fuel injection operation in step S204, and the startup fuel injection time T calculated in step 101 is calculated.
Fuel is injected during OUT. That is, as shown in FIG. 8B, at the time of generation of the CRK signal pulse after the generation of the 2TDC determination signal, the fuel injection time TO at the time of starting by the fuel injection valve 6
UT fuel injection is performed.

As described above, when it is determined that the fuel pressure has not reached the predetermined value PFATH at the fuel injection timing at start calculated in step S101, the fuel injection timing at start is delayed so that the rise of the fuel pressure is in time. (For example, 1TD
C CRK signal pulse is generated after generation of the C discrimination signal From the start of cranking CRK after generation of the 2TDC discrimination signal
Since the signal pulse is delayed when the signal pulse is generated), the fuel is injected with the required fuel pressure secured, and the fuel injection time TOUT
The fuel for the minute is surely injected. Therefore, it is possible to sufficiently improve the startability, and particularly when the ignition switch 24 is operated immediately and the fuel is immediately started when the time between the operation to the ON position and the operation to the start position is very short. The startability is improved when the rise of the fuel pressure is slow such as when the gas temperature is high.

When it is determined in step S202 that the flag F1 is set to "1", it is not necessary to determine whether or not the rising of the fuel pressure is in time for the fuel injection timing at startup set in step S101. When the CRK signal pulse is generated after the 1TDC determination signal is generated, the fuel injection valve 6 performs the fuel injection for the startup fuel injection time TOUT.

In the present embodiment, the example in which the fuel injection timing at the start is the time when the CRK signal pulse is generated after the generation of the 2TDC discrimination signal from the cranking start time has been described, but the fuel injection timing at the start is the fuel pressure. Is sequentially delayed to the next injection timing until it is determined that has reached the predetermined value PFATH. For example, the fuel injection timing at the start is from the cranking start time to the CRK signal pulse generation after the 3TDC determination signal generation. Sometimes.

As described above, according to the present embodiment, the stop period of the engine 1 is obtained based on the engine water temperature TW and the intake air temperature TA, and when the obtained stop period is long, it is estimated by the engine water temperature TW and the intake air temperature TA. The rise time of the fuel pressure is estimated based on the estimated fuel gas temperature, the fuel injection timing at start is delayed according to the estimated rise time of the fuel pressure, and the fuel injection is performed with the required fuel pressure secured. It is possible to reliably inject the fuel for the time TOUT and sufficiently improve the startability.

In this embodiment, when it is determined that the rise of the fuel pressure is not in time for the fuel injection timing at startup set in step S101, the fuel injection timing at startup is delayed, but instead of this, , Ignition switch 25
It is also possible to use a method in which the starter 26 is set to operate after a predetermined time has elapsed from the time when the start signal is output, so that the fuel pressure rises to a predetermined value by the fuel injection timing at start-up calculated in step S101. it can.

It is also possible to use a method of directly measuring the fuel pressure and detecting whether or not the measured fuel pressure has reached a predetermined pressure.

(Second Embodiment) Next, a second embodiment of the present invention will be described. FIG. 9 shows a second embodiment of the present invention.
FIG. 10 is a flowchart showing fuel injection control by the internal combustion engine startup fuel supply control device according to the embodiment, and FIG. 10 is a timing chart showing startup fuel injection timing and startup fuel injection time determined by the fuel injection control of FIG. 9. is there.

In the present embodiment, the starting fuel injection condition determining process is executed by the same method as in the first embodiment, but the fuel injection control is different from that in the first embodiment, and the starting fuel injection condition is different. Instead of delaying the injection timing, additional fuel injection is performed. In the present embodiment, parts different from the first embodiment will be described.

In the fuel injection control of the present embodiment, as shown in FIG. 9, when it is determined in step S303 that the time TISTA is shorter than the fuel pressure rising time TPFR calculated in step S103 (shown in FIG. 3), the fuel pressure Is a predetermined value PFA
It is determined that TH has not been reached, and step S304
Proceed to.

In step S304, it is designated to execute the additional fuel injection by the fuel injection valve 6. In this additional fuel injection, the startup fuel injection time TOUT calculated in step S101 is increased by a predetermined time DTOUT, and the increased startup fuel injection time (TOUT + DTOUT) is set and the subsequent additional fuel injection timing. It is set to be distributed to and to be injected.

Next, in step S305, a drive signal is supplied to the fuel injection valve 6 so that the additional fuel injection set in step S304 is executed when the CRK signal pulse is generated after the 1TDC discrimination signal is generated.

More specifically, as shown in FIG. 10, the fuel injection timing at startup is set at step S101 described above, that is, the fuel injection timing at startup, that is, the CR after the 1TDC determination signal is generated.
When the K signal pulse is generated, the fuel injection is performed for the time TOUT1 minute from the fuel injection timing at the time of starting, and the fuel injection is performed for the time TO after the predetermined time DT has elapsed from the completion of the fuel injection.
Do 2 minutes for UT. Fuel injection is performed. In addition, time TOU
The value obtained by adding T1 and the time TOUT2 is equal to the fuel injection time at start (TOUT + DTOUT).

Further, in step S302, it is determined that the flag F1 is set to "1", that is, it is unnecessary to determine whether or not the rising of the fuel pressure is in time for the fuel injection timing at startup set in step S101. It is determined or time TISTA is step S10 in step S303.
If it is determined that it is longer than the fuel pressure rise time TPFR calculated in step 3, the fuel injection valve 6 performs fuel injection for the startup fuel injection time TOUT at the time of generation of the CRK signal pulse after generation of the 1TDC determination signal in step S305. .

As described above, according to the present embodiment, when it is determined that the rising of the fuel pressure does not meet the fuel injection timing at startup set in step S101, the fuel injection time at startup is increased by the additional fuel injection. Therefore, the fuel is injected in a state where the required fuel pressure is not secured, but by increasing the fuel injection time, it is possible to sufficiently improve the startability, and especially when starting immediately and when the gas temperature of the fuel is high. The startability is improved when the rise of the fuel pressure is slow.

(Third Embodiment) Next, a third embodiment of the present invention will be described. FIG. 11 is a flow chart showing fuel injection control by a start-time fuel supply control device for an internal combustion engine according to a third embodiment of the present invention, and FIG. 12 is a start-time fuel injection timing and start determined by the fuel injection control of FIG. 7 is a timing chart showing the hour fuel injection time.

In this embodiment, the starting fuel injection condition determination process is executed by the same method as in the first embodiment, but the fuel injection control is different from that in the first embodiment, and the starting fuel injection condition is different. Instead of delaying the injection timing, the fuel injection time is increased. In the present embodiment, parts different from the first embodiment will be described.

In the fuel injection control of this embodiment, FIG.
As shown in FIG. 5, when it is determined that the time TISTA is shorter than the fuel pressure rising time TPFR calculated in step S103 (shown in FIG. 3) in step S403, the fuel pressure is determined to be the predetermined value PF.
It is determined that ATH has not been reached, and step S40
Go to 4.

In step S404, step S101
The starting fuel injection time TOUT calculated in
It is increased by OUT, and the fuel injection time at startup is set to the fuel injection time at startup (TOUT + DTOUT).

Next, at the time of generation of the CRK signal pulse after the generation of the 1TDC discrimination signal at step S405, the fuel injection time at start (TOUT + D) increased at step S404.
A drive signal is supplied to the fuel injection valve 6 so as to perform fuel injection during (TOUT).

Specifically, as shown in FIG. 12, the fuel injection timing at startup is set at step S101, that is, the fuel injection timing at startup, that is, the CR after the 1TDC determination signal is generated.
When the K signal pulse is generated, the fuel injection is started from the fuel injection timing at the time of start calculated in step S101 above (TO
UT + DTOUT).

Further, in step S402, it is determined that the flag F1 is set to "1", that is, it is unnecessary to determine whether or not the rise of the fuel pressure is in time for the fuel injection timing at startup set in step S101. It is determined or the time TISTA is step S10 in step S403.
If it is determined that it is longer than the fuel pressure rising time TPFR calculated in step 3, the fuel injection valve 6 performs fuel injection for the startup fuel injection time TOUT at the time of generation of the CRK signal pulse after generation of the 1TDC determination signal in step S405. .

As described above, according to the present embodiment, if it is determined that the rise of the fuel pressure is not in time for the fuel injection timing at the start set in step S101, the fuel injection time at the start is increased. Fuel is injected in the state where the fuel pressure is not secured, but by increasing the fuel injection time, it is possible to sufficiently improve the startability, and especially when starting immediately or when the fuel gas temperature is high, the rise of the fuel pressure occurs. Startability at a slow speed is improved.

[0079]

As described above, according to the internal combustion engine starting-time fuel supply control device of the first aspect, at least one of the engine temperature and the engine environment temperature at the time of starting the engine is detected, and the detection is performed. Based on at least one of the engine temperature and the engine environment temperature, the fuel pressure rise time from when the engine is started until the pressure of the fuel supplied to the fuel injection means reaches a predetermined value is estimated, and the fuel pressure rise time is estimated according to the estimated fuel pressure rise time. Since the fuel supply at the engine start is controlled by the engine start, the fuel supply control at the start can be performed in consideration of the fuel rise time that changes depending on the fuel temperature, and the startability can be sufficiently improved.

According to the fuel supply control device for starting the internal combustion engine according to the second aspect, the engine cooling water temperature can be used as the engine temperature.

According to the fuel supply control device for starting the internal combustion engine according to the third aspect, the engine intake air temperature can be used as the engine environmental temperature.

According to the fuel supply control device for starting the internal combustion engine according to the fourth aspect, execution of fuel injection by the fuel injection means is delayed according to the estimated fuel pressure rise time.
It is possible to perform the fuel injection operation that secures a predetermined fuel pressure, and it is possible to improve the startability, particularly the immediate startability.

According to the fuel supply control device for starting the internal combustion engine according to the fifth aspect of the invention, the additional fuel injection is executed by the fuel injection means in accordance with the estimated fuel pressure rise time. The amount of fuel is increased, and startability including immediate startability can be improved.

According to the fuel supply control device for starting the internal combustion engine according to the sixth aspect, the valve opening time of the fuel injection means is increased according to the estimated rise time of the fuel pressure. Therefore, the starting time is increased by increasing the valve opening time. It is possible to improve the startability including the immediate startability by increasing the amount of fuel supplied.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a control device including a start-time fuel supply control device for an internal combustion engine according to a first embodiment of the present invention.

FIG. 2 is a flow chart showing a fuel injection control at startup which is executed by the control device of FIG.

FIG. 3 is a flowchart showing a startup fuel injection condition determination process of FIG.

FIG. 4 is a diagram showing temporal changes in engine water temperature and intake air temperature after the engine is stopped.

5 is a time chart showing the relationship between the rising of fuel pressure and the fuel injection timing at startup in the startup fuel injection condition determination processing of FIG. 3. FIG.

FIG. 6 is a diagram showing a fuel pressure rise time table used in the fuel injection condition determination process at startup in FIG.

FIG. 7 is a flowchart showing the fuel injection control of FIG.

8 is a timing chart showing a fuel injection timing at startup and a fuel injection time at startup determined by the fuel injection control of FIG. 7.

FIG. 9 is a flow chart showing a fuel injection control by a start-time fuel supply control device for an internal combustion engine according to a second embodiment of the present invention.

10 is a timing chart showing a fuel injection timing at startup and a fuel injection time at startup determined by the fuel injection control of FIG. 9.

FIG. 11 is a flow chart showing a fuel injection control by a start-time fuel supply control device for an internal combustion engine according to a third embodiment of the present invention.

12 is a timing chart showing a fuel injection timing at startup and a fuel injection time at startup determined by the fuel injection control of FIG. 11.

[Explanation of symbols]

 1 Engine (Internal Combustion Engine) 5 ECU (Fuel Supply Control Device at Startup) 6 Fuel Injection Valve 9 Intake Temperature Sensor 10 Engine Water Temperature Sensor 12 CRK Sensor 19 Spark Plug 22 Pressure Regulator 25 Ignition Switch 26 Starter 27 Battery Voltage Sensor

Claims (6)

[Claims] 1. A fuel injection means for injecting fuel into an intake passage of an internal combustion engine, a fuel pressure adjusting means for adjusting the pressure of fuel supplied to the fuel injection means to a predetermined value, and a fuel supply for the engine. A starting fuel supply control device for an internal combustion engine, comprising: a fuel supply control means for controlling; a temperature detecting means for detecting at least one of an engine temperature and an engine environment temperature at the time of starting the engine; and the detected engine temperature and engine temperature. A fuel pressure control means for estimating a fuel pressure rising time from when the engine is started to when the pressure of the fuel supplied to the fuel injection means reaches the predetermined value based on at least one of environmental temperatures; A means for controlling the fuel supply at the time of starting the internal combustion engine, wherein the means controls the fuel supply at the time of starting the engine according to the estimated fuel pressure rise time. 2. The start-up fuel supply control device for an internal combustion engine according to claim 1, wherein the engine temperature is an engine cooling water temperature. 3. The internal combustion engine start-time fuel supply control device according to claim 1, wherein the engine environmental temperature is an engine intake air temperature. 4. The fuel supply control means delays execution of fuel injection by the fuel injection means according to the estimated fuel pressure rise time, according to any one of claims 1 to 3. A fuel supply control device for starting an internal combustion engine. 5. The internal combustion engine according to claim 1, wherein the fuel supply control means causes the fuel injection means to execute additional fuel injection according to the estimated fuel pressure rise time. Fuel supply control device at engine startup. 6. The internal combustion engine according to claim 1, wherein the fuel supply control means increases the valve opening time of the fuel injection means according to the estimated fuel pressure rise time. Fuel supply control device at engine startup.