JPH0433974B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel supply control method during acceleration of an internal combustion engine, which controls a fuel metering device that supplies fuel to the internal combustion engine to increase the amount of fuel, especially during cold acceleration. .

In an internal combustion engine, the amount of fuel is controlled by electronically controlling the opening time of an injection fuel metering device that supplies fuel to a gasoline engine, and the air-fuel ratio of the air-fuel mixture supplied to the engine. In such a fuel supply control device, the valve opening time of the fuel metering device is set to a reference value depending on the engine speed and the absolute pressure in the intake pipe, and the specifications representing the operating state of the engine, such as engine speed. The fuel supply control method is determined by adding and/or multiplying constants and/or coefficients depending on the number, absolute pressure in the intake pipe, engine water temperature, throttle valve opening, exhaust concentration (oxygen concentration), etc. Traditionally known. Further, the reference value is corrected by an increase coefficient calculated according to engine temperature and engine load (for example, intake pressure) during a first idle in the engine warm-up process or in a steady state of the engine during the warm-up process. has also been proposed previously. The above increase coefficient is
In addition to enriching the air-fuel ratio to overcome the increase in engine friction during engine warm-up, the amount of fuel adhering to the intake pipe increases as the engine temperature decreases and the engine load increases. It is controlled to become even richer.

However, the above increase coefficient is determined by supplying the fuel adhering to the intake pipe in advance in a steady operating state, so that the amount of fuel adhering to the intake pipe and the amount of fuel sucked into the cylinder after the adhering fuel evaporates are in equilibrium. This function corrects the amount of fuel adhering to the intake pipe during transient operating conditions such as acceleration, which disrupts the equilibrium state of fuel adhering to the intake pipe due to a delay in detecting engine load parameters, making it difficult to manage the air-fuel ratio. The problem was that it was difficult to do.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to improve acceleration performance by more appropriately increasing the amount of fuel during acceleration during cold conditions.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an overall configuration diagram of an apparatus for carrying out the method of the present invention. Reference numeral 1 indicates, for example, a four-cylinder internal combustion engine, and the engine 1 has four main combustion chambers and an auxiliary combustion chamber connected thereto. It is of the type consisting of a chamber (both not shown). Intake pipe 2 for engine 1
The intake pipe 2 includes a main intake pipe communicating with each main combustion chamber and a sub intake pipe (both not shown) communicating with each sub combustion chamber. A throttle body 3 is provided in the middle of the intake pipe 2, and a main throttle valve and a sub-throttle valve (both not shown) disposed inside the main intake pipe and a sub-intake pipe, respectively, are provided in conjunction with each other. A throttle valve opening sensor 4 is connected to the main throttle valve to convert the valve opening of the main throttle valve into an electrical signal and send it to an electronic control unit (hereinafter referred to as "ECU") 5.

A fuel injection device 6 is provided in the intake pipe 2 between the engine 1 and the throttle body 3. This fuel injection device 6 consists of a main injector and a sub-injector (both not shown).The main injector is located in the main intake pipe slightly upstream of the intake valve (not shown) for each cylinder, and the sub-injector is located in the sub-intake pipe. These throttle valves are common to each cylinder and are provided slightly downstream of the sub-throttle valve. The fuel injection device 6 is connected to a fuel pump (not shown). Main injector and sub injector are ECU5
The fuel injection valve opening time is controlled by a signal from the ECU 5.

On the other hand, an absolute pressure sensor 8 is provided immediately downstream of the main throttle valve of the throttle body 3 via a pipe 7, and an absolute pressure signal converted into an electrical signal by the absolute pressure sensor 8 is sent to the ECU 5.
sent to. Also, downstream of it is an intake air temperature sensor 9.
is installed, and this intake air temperature sensor 9 also converts the intake air temperature into an electrical signal and sends it to the ECU 5.

Engine water temperature sensor 10 is installed in the main body of engine 1.
The sensor 10 is made of a thermistor or the like, and is inserted into the circumferential wall of the engine cylinder filled with cooling water, and supplies the detected water temperature signal to the ECU 5.

An engine rotation speed sensor (hereinafter referred to as "Ne sensor") 11 and a cylinder discrimination sensor 12 are installed around the camshaft or crankshaft (not shown) of the engine. At a predetermined crank angle position every 180° rotation, the latter cylinder discrimination sensor 12
outputs one pulse each at a predetermined crank angle position of a specific cylinder, and these pulses are sent to the ECU 5.

A three-way catalyst 14 is disposed in the exhaust pipe 13 of the engine 1 to purify HC, CO, and NOx components in the exhaust gas. On the upstream side of this three-way catalyst 14,
An O ₂ sensor 15 is inserted into the exhaust pipe 13 , and this sensor 15 detects the oxygen concentration in the exhaust gas and supplies the detected value signal to the ECU 5 .

Further, the ECU 5 is connected to a sensor 16 that detects atmospheric pressure, an engine starter switch 17, and a battery electrode 18, and the ECU 5 receives a detected value signal from the sensor 16, a voltage signal from the battery electrode, and a starter switch ON. - Provided with an off-state signal.

Next, details of the fuel control operation of the electronic fuel injection control device of the present invention having the above-described configuration will be explained with reference to FIGS. 1 and 2 to 14 described above.

First, FIG. 2 shows the air-fuel ratio control of the present invention, that is,
This is a block diagram showing the overall program configuration of the control contents of the main and sub-injector valve opening times T _OUTM and T _OUTS in the ECU 5. It consists of a main program 1 and a sub-program 2, and the main program 1 is based on the engine speed Ne.
The subprogram 2 performs control in synchronization with the TDC signal and consists of a starting control subroutine 3 and a basic control program 4. On the other hand, the subprogram 2 consists of an asynchronous control subroutine 5 when not synchronized with the TDC signal.

The basic calculation formula in the start control subroutine 3 is expressed as T _OUTM = T _iCRM ×K _Ne + ( _TV + ΔT _V ) (1) T _OUTS = T _iCRS × K _Ne + T _V (2). Here, T _iCRM and T _iCRS are reference values for the valve opening times of the main and sub-injectors, respectively, and are determined by T _iCRM and T _iCRS tables 6 and 7, respectively. K _Ne is a correction coefficient at the time of starting specified by the rotational speed Ne, and is determined by the K _Ne table 8. T _V is _a constant for adjusting the valve opening time to increase or decrease according to changes in battery voltage.
It is determined from Table ₉ , and ΔT _V is added to the main injector in accordance with the operating characteristics of the injector due to the difference in structure compared to the TV for the sub-injector.

The basic calculation formula in basic control program 4 is T _OUTM = (T _iM − T _DEC ) × (K _TA・K _TW・K _AFC・K _pA・K _AST・K _WOT・K _O2・K _LS ) +T _ACC × ( K _TA・K _TWT K _AFC ) + ( _TV + ΔT _V ) _{T OUTS} = (T _iS − T _DEC )×(K _TA・K _TW・K _AST・K _PA )+TV (4). Here, T _iM and T _iS are reference values for the valve opening times of the main and sub-injectors, respectively, and are calculated from the basic T _i map 10, respectively.
T _DEC and T _ACC are constants during deceleration and acceleration, respectively, and are determined by the acceleration and deceleration subroutine 11. Various coefficients such as K _TA , K _TW . . . are calculated by respective tables and subroutines 12. K _TA is the intake air temperature correction coefficient calculated from the table based on the actual intake air temperature, K _TW is the fuel increase coefficient calculated from the table based on the actual engine water temperature T _W , and K _AFC is the fuel cut calculated by the subroutine. After fuel increase factor, K _PA
is the atmospheric pressure correction coefficient determined from the table based on the actual atmospheric pressure, K _AST is the post-start fuel increase coefficient determined by the subroutine, and K _WOT is a constant that is the enrichment coefficient of the mixture when the throttle valve is fully opened. , K _O2 is an O ₂ feedback correction coefficient determined by a subroutine according to the actual oxygen concentration in exhaust gas, and K _LS is a constant that is a lean coefficient of the air-fuel mixture during lean/stoichiometric operation. Stoichiometric is an abbreviation for Stoichiometric, which indicates stoichiometric amount, that is, the theoretical air-fuel ratio. Further, T _ACC is a fuel increase constant during acceleration determined by the subroutine, and is determined from a predetermined table.

On the other hand, the formula for calculating the asynchronous control subroutine 5 of the main injector opening time A _MA that is not synchronized with the TDC signal is T _MA = T _iA ×K _TWT・K _AST + (T _V + ΔT _V ) ...(5) It is expressed as Here, T _iA is the asynchrony during acceleration,
That is, it is a fuel increase reference value during acceleration control that is not synchronized with the TDC signal, and is determined from the T _iA table 13.
K _TWT is a fuel increase coefficient during synchronous acceleration, after acceleration, and asynchronous acceleration calculated based on the water temperature increase coefficient K _TW obtained from Table 14.

FIG. 3 shows a flowchart of the main program 1 when controlling the valve opening time in synchronization with the TDC signal in the ECU 5, and the entire program consists of an input signal processing block A, a basic control block B, and a starting control block C. Become. First, in input signal processing block A, when an engine ignition switch (not shown) is turned on, the CPU is initialized (step 1), and a TDC signal is input when the engine is started (step 2). Then all the basic analog values, atmospheric pressure P _A from each sensor, absolute pressure
P _B , engine water temperature T _W , intake air temperature T _A , battery voltage V of the valve body, throttle valve opening θth, output voltage value V of the O ₂ sensor, and on/off state of the starter switch 17 are read into the ECU 5, Store the necessary values (step 3). Then the first TDC
Count the elapsed time from the signal to the next TDC signal, calculate the engine speed Ne based on that value, and store it in the ECU 5 (step 4).
Based on the calculated value of Ne, it is determined whether the engine speed is less than or equal to the cranking speed (starting speed) (step 5), and the answer is affirmative (Yes).
If so, it is sent to the startup control subroutine,
T _iCRM and T _iCRS are determined based on the engine cooling water temperature T _W using the T _{iCRM table} and the T _iCRS table (step 6), and the correction coefficient KNe of Ne is determined using the KNe table (step 7). And _T.V.
Determine the battery voltage correction constant T _V from the table (step 8), and calculate T _OUTM and T _OUTS by substituting each value into the above equations (1) and (2) (step 9).

Also, if the answer is no in step 5,
If so, it is determined whether or not the engine is in a state where the fuel should be cut (step 10);
If the answer is yes, the values of T _OUTM and T _OUTS are both set to zero and a fuel cut is performed (step 11).

On the other hand, if the answer is determined to be no, each correction coefficient K _TA , K _TW , K _AFC , K _PA , K _AST , K _WOT ,
K _O2 , K _LS , K _TWT etc. and correction constants T _DEC , T _ACC ,
Calculate T _V and ΔT _V (step 12). These correction coefficients and constants are determined by subroutines and
These are determined by tables, etc., and - indicates - in those subroutines.
This applies to

Next, a predetermined corresponding map is selected according to each data of rotation speed Ne and absolute pressure P _B , and T _iM and T _iS are determined based on the map (step 13). Then, based on the correction coefficient value, correction constant value, and reference value obtained in steps 12 and 13 above, the previous formula is
Calculate T _OUTM and T _OUTS using (3) and (4) (step 14). Then, the main and sub-injectors are operated respectively based on the values of T _OUTM and T _OUTS obtained in this way (step 15).

The specific contents of the TDC signal synchronization control described above will be explained in detail below.

TDC signal synchronous control water temperature increase coefficient K _TW Figure 4 shows engine water temperature T _W and water temperature increase coefficient K _TW
This is a K _TW table showing the relationship between First, water temperature
When T _W is above a certain value T _W5 (e.g. 60℃)
K _TW is 1, but if the temperature drops below T _W5 , 5 points of K _TW are set for each of the 5 levels of temperature T _{W1 to 5} provided as calibration variables, and the water temperature T When _W takes a value other than each variable value T W1 to T _W5 , it is determined by interpolation calculation. Figure 5 is a graph showing the function of _the absolute pressure P _B and _the coefficient K _TW when the water _temperature T _W is the same.
Hg) and two criteria are established, and the absolute pressure P _B is less than P _B1 ,
And when P _B2 or more, K _TW takes a constant value, but
When it is between P _B1 and P _B2 , K _TW is obtained by performing interpolation calculation.

Water temperature increase coefficient K _TWT during synchronous _acceleration and asynchronous acceleration Water temperature increase coefficient K TWT during acceleration control synchronized with the TDC signal (hereinafter referred to as synchronous acceleration) and asynchronous acceleration
is determined by the following formula based on the above K _TW .

K _TWT = C _TWT (K _TW −1) + 1.0 (6) Here, C _TWT is a calibration variable and is set, for example, in the range of 1-3.

Subroutine for calculating fuel increase constant T _ACC during synchronous acceleration FIG. 6 shows a flowchart of a subroutine for calculating fuel increase constant T _ACC during acceleration in control synchronized with the TDC signal.

First, when each pulse of the TDC signal is input, the throttle valve opening value θn is read (step 1). Next, the value θn-1 of the throttle valve opening in the previous loop is retrieved from the memory (step 2), and the value θn-1 is retrieved from the memory (step 2).
The difference Δθn between θ(n-1) is the predetermined synchronous acceleration determination value G ⁺
(Step 3) If the answer is yes, it is determined whether the difference ΔΔθn between the above difference Δθn and the difference Δθn−1 in the previous loop is 0 or positive. It is determined (step 4) that if Yes, it is accelerated, and if No, it is determined that it is after acceleration. That is, as shown in Fig. 7, the above ΔΔθn is differentiated twice with respect to the throttle valve opening θn, and the inflection point of the throttle valve opening θn curve is used as a reference in the direction of change in the throttle valve opening. Therefore, it is determined whether it is accelerated or after acceleration. If it is determined in step 4 that it is an acceleration, the number of post-acceleration fuel increase pulses _N2 corresponding to the amount of change Δθn is set as the count number N _PACC in the post-acceleration counter (step 5). Figures 8 and 9 show the relationship between the amount of change in the throttle valve opening Δθn and the fuel increase constant T _ACC during acceleration, and the relationship between the count number N _PACC of the post-acceleration counter and the fuel increase constant T _PACC after acceleration. This is a table showing each relationship. In Fig. 8, the fuel increase constant during acceleration T ACCo corresponding to the amount of change Δθn is determined, and in Fig. 9, the corresponding post-acceleration fuel increase constant T _ACCo is determined.
T _PACCo is determined, and the number of post-acceleration fuel increase pulses N ₂ is determined from the constant T _PACCo . In other words, when the amount of change Δθn in the throttle valve opening is large, the increase value after acceleration is also large, and the count number N _PACC after acceleration is also increased in order to maintain the increase time for a long time. The number N _PACC is also made small.

Simultaneously with step 5 described above, the increase value T _ACC during acceleration is determined from the table shown in FIG. 8 based on the amount of change Δθn in the throttle valve opening (step 6). Then, set the calculated T _ACC value in the basic formula, and
Set the fuel reduction constant T _DEC during deceleration to 0 (step 7).

Standard value for main and sub-injector opening time
Determination of T _iM and T _iS These reference values T _iM and T _iS are determined by a plurality of predetermined engine speed Ne values and a plurality of predetermined absolute pressures PB, respectively.
It is determined by using the value as a parameter and selecting a map value corresponding to the detected engine rotation value and absolute pressure value.

TDC signal asynchronous control In the present invention, the above-mentioned
In addition to output control of the valve opening time of the main and sub-injectors in synchronization with the TDC signal, asynchronous control is performed in which the main injector is controlled in synchronization with a pulse train that is not synchronized with the TDC signal but has a fixed time interval. However, this asynchronous control will be explained below. As described above, the main injector opening time T _MA in asynchronous control is calculated using the above equation (5).

The above asynchronous control is used, for example, during sudden acceleration.
This is done to compensate for the shortage in the synchronous acceleration increase according to the TDC signal.

Asynchronous Acceleration Subroutine FIG. 10 shows a flowchart of the asynchronous acceleration subroutine. First, an asynchronous signal is input to a predetermined counter in the ECU at fixed time intervals (for example, every 20 ns) independently of the TDC signal pulse (step 1). The pulse interval of the asynchronous signal is set in the range of 10 to 50 ms. Next, the throttle valve opening value θ _Ao is read into a predetermined register in the ECU each time the asynchronous signal pulse is input (step 2). Throttle valve opening value θ _Ao-1 and engine speed Ne at the time of previous pulse input stored in the register
is taken out from each register (step 3). It is determined whether or not the engine rotational speed Ne is smaller than a predetermined asynchronous acceleration determination rotational speed _NEA (for example, 2800 rpm) (step 4). The asynchronous acceleration determination rotation speed _NEA is set, for example, in a range of 50 to 6000 rpm. If the answer to the above judgment is No, the number of pulses N _ACCA stored in a predetermined register is reset to a predetermined initial value N _AA (for example, 2) (step 5). If the answer is yes in step 4, the difference between the throttle valve opening values θ _Ao and θ _Ao-1 , that is, the amount of change Δθ _A , is set to a predetermined value G _A (for example, 20°/ sec) (step 6). The answer is no.
In this case, the process moves to step 5 described above. Also, if the answer is affirmative (Yes), the number of stored pulses is
It is determined whether N _ACCA is greater than 0 (step 7), and if the answer is affirmative, the asynchronous acceleration increase reference value T _iA is determined from the table shown in FIG. 11 (step 8). Figure 11 shows the amount of change in throttle valve opening Δθ _A and the asynchronous acceleration increase reference value T _iA
This is a table showing the relationship between T _iA
seek. Next, the valve opening time T _MA of the main injector is calculated using the above equation (5) (step 9).
In this case, the coefficient K _TWT , constant T _V , and ΔT _V are updated every time a pulse of the TDC signal is input, as described above. Valve opening time calculated in the above steps
The valve opening time of the main injector is controlled based on T _MA (step 10), and the valve opening time of the main injector is controlled based on the
At the same time, each time a pulse of the asynchronous signal is input, 1 is subtracted from the pulse number N _ACCA (step 11) until the pulse number N _ACCA becomes 0, that is, the answer becomes negative (No) in step 7. The above valve opening time control routine is performed.

Note that when the asynchronous control output and the TDC synchronous control output conflict in terms of time, the TDC synchronous control output is given priority.

FIG. 12 is a circuit diagram of the internal configuration of the ECU 5 shown in FIG. 1 used in the above-described fuel injection amount control method of the present invention, and particularly shows the fuel supply control circuit portion during acceleration. Engine rotation sensor 11 in FIG.
is connected to a one-shot circuit 501 including a waveform shaping circuit, and the output of this one-shot circuit 501 is connected to each input side of a synchronous Ti _(S) value calculation circuit 502 and a control circuit 504. The cylinder discrimination sensor 12 in FIG. 1 is connected to the input side of a control circuit 504 via a one-shot circuit 505 including a waveform shaping circuit. The output signal of _the starter switch ₁₇ in FIG. At the same time, it is connected to the input side of the control circuit 504 via a one-shot circuit 507.

The output values from the absolute pressure sensor 8, engine water temperature sensor 10, and throttle sensor 4 in FIG. 1 are respectively P _B value register 508 and T _W value register 509.
and Δθn value register 510, and P _B
The value register 508 and the T _W value register 509 are the synchronous Ti _(S) value calculation circuit 502 and the synchronous Ti _(M) value calculation circuit 5.
03 and the asynchronous Ti value calculation circuit 522, respectively. One input terminal A of the comparison circuit 520a
The output side of the Δθn value register 510 is connected to
A predetermined acceleration determination value G ⁺ is input to the other input terminal B. The output side of this comparison circuit 520a is connected to the input side of the synchronous Ti _(M) value calculation circuit 503. The output side of the Δθn value register 510 is also connected to one input terminal A' of the comparison circuit 520b, and a predetermined acceleration determination value G _A is input to the other input terminal B'. The output side of this comparison circuit 520b is connected to the input side of the asynchronous Ti value calculation circuit 522. Furthermore, the output side of the clock generation circuit 521 is connected to the input side of the asynchronous Ti value calculation circuit 522.

The output side of the synchronous Ti _(S) value calculation circuit 502 is connected to the Ti _(S) value control circuit 511 and further to the sub-injector 601 of the fuel injection device 6 of FIG. 1 via an injector drive circuit 512. synchronization
The output side of the Ti _(M) value calculation circuit 503 is an AND circuit 51
3a to 513d, and the output sides of the AND circuits 513a to 513d are connected to Ti _(M1-4) value control circuits 514a to 514, respectively.
d, main injector 602a of the fuel injection device 6 of FIG. 1 via OR circuits 515a to 515d and injector drive circuits 516a to 516d.
~602d, respectively, in this order. The output side of the control circuit 504 is connected to the other input sides of the AND circuits 513a to 513d, respectively, and is also connected to the input side of the synchronous Ti _(M) value calculation circuit 503. The input terminal 531a of the comparator circuit 531 is connected to the _NEA value memory 532 and the input terminal 5
31b is connected to the Ne value register 533 which stores the Ne value corresponding to the engine rotation speed according to the TDC signal, and the output terminal 51
3c is connected to the other input terminal of the AND circuit 530. Here, the value N _E corresponding to the engine speed is measured by the N _E measurement circuit 535 as a time value between TDC signals, and its output is the N E value register 535.
33. The output side of this AND circuit 530 is connected to the input side of an asynchronous Ti value control circuit 534, and the output side of the asynchronous Ti value control circuit 534 is connected to the other input side of the OR circuits 515a to 515d, respectively.

A correction coefficient calculation circuit 540 as shown in FIG. 13 is configured in the synchronous Ti _(M) value calculation circuit 503 and the asynchronous Ti value calculation circuit 522. This correction coefficient calculation circuit 540 is a cooling water temperature increase coefficient other than acceleration.
The cooling water temperature increase coefficient K _TWT during acceleration is calculated from K _TW . One input side of the subtraction circuit 541 is the output side of the memory storing the correction coefficient K _TW , and the other input side is the value. The output sides of the memories 542 in which 1 is stored are connected to each other, and the output side of the subtraction circuit 541 is connected to one input side of the multiplication circuit 543. The other input side of this multiplier circuit 543 is connected to the output side of a memory 544 in which a predetermined constant C _TWT is stored, and the output side is connected to one input side of an adder circuit 545 . The output side of the memory 542 is connected to the other input side of the adder circuit 545. Multiplication circuit 5
On one input side of 46, there is a synchronous Ti _(M) value calculation circuit 5.
03, the acceleration fuel increase constant T _ACC is used, and the asynchronous Ti value calculation circuit 522 uses the fuel increase constant Ti _A
are respectively input from the map, and the output side of the adder circuit 545 is connected to the other input side.

The operation of the circuit configured as above will be explained below.

When the starter switch 17 is actuated, the switch-on signal is shaped into a step-like square wave by the Schmitt circuit 506 and output as an ST signal to the one-shut circuit 507, the synchronous Ti _{(S) value calculation circuit 502, and the synchronous Ti (S)} value calculation circuit 502.
It is applied to the Ti _(M) value calculation circuit 503. When the ST signal is input to the one-shot circuit 507, the one-shot circuit 507 outputs a pulsed rectangular wave signal.
This signal is applied as a start command signal to the control circuit 504 and a basic Ti value calculation circuit (not shown). When the start command signal is applied from the one-shot circuit 507, the basic Ti value calculation circuit calculates the basic (initial) injection time Ti _of the injector immediately after the starter switch is turned on based on the engine water temperature T _W and battery voltage TV. The injector 602a responds to the calculated valve opening time Ti.
~602d and start the engine. This fuel injection amount control at the time of startup is disclosed in detail in a patent application specification (Japanese Patent Application No. 89930/1989) previously filed by the applicant of the present invention.

Regarding the valve opening control of the sub-injector, the TDC synchronization signal is sent to the one-shot circuit 501 immediately after starting.
The sub-injector valve opening time Ti according to the output signals of the engine water temperature T _W value register 509 and the absolute pressure P _B value register 508 is synchronized with the synchronized Ti _(S) value calculation circuit 502 each time the synchronized Ti (S) value calculation circuit 502 receives the signal. _(S) value is calculated by the synchronous Ti _(S) value calculation circuit 502, and Ti _(S)
The value is input to the value control circuit 511. The Ti _(S) value control circuit 511 supplies an output signal to the sub-injector drive circuit 512 during a predetermined valve opening time corresponding to the valve opening time Ti _(S) , and the sub-injector drive circuit 512 supplies a drive output to the sub-injector 601. Then, the sub-injector 601 is controlled to open.

The control circuit 504 becomes activated when the ST signal is input, and determines the order of fuel injection to each cylinder based on the TDC synchronization signal and cylinder discrimination signal input from the one-shot circuits 501 and 505 as the engine rotates after the engine starts. The determined signal is outputted and applied to the AND circuits 513a to 513d sequentially to sequentially enable these AND circuits 513a to 513d, and a start command signal synchronized with the TDC synchronization signal is output to synchronize Ti _{(M )} value calculation circuit 503.

The synchronous Ti _(M) value calculation circuit 503 operates when the ST signal is input, and calculates the values from the absolute pressure P _B value register 508 and the engine water temperature T _W value register 509 in synchronization with the start command signal input from the control circuit 504. The valve opening time Ti _(M) is calculated based on the input signal and a corresponding signal is output. This signal is sequentially applied to Ti _(M) value control circuits 514a to 514d via AND circuits 513a to 513d. Each of these Ti _(M) value control circuits 514a to 514d outputs a signal to the injector drive circuits 516a to 516d via OR circuits 515a to 515d for a predetermined time according to the input valve opening time Ti _(M). , each of these injector drive circuits 516a to 516d outputs a drive signal while the above signal is applied to sequentially open the main injectors 602a to 602d and inject fuel into each corresponding cylinder.

The comparison circuit 531 operates when the relationship of B ₁ >A ₁ holds between the two input signals A ₁ and B ₁ , that is,
The value corresponding to the engine speed Ne input from the engine speed Ne value register 533 is N _{EA .}
is smaller than the value corresponding to the output terminal 53.
A signal 1 is output from 1c, and in addition to the AND circuit 530, the AND circuit 530 is enabled. Here, the N _EA value memory and the N _E value register are values that are inversely proportional to the rotational speed, so if they correspond to the actual engine rotational speed, when the actual engine rotational speed is higher than N _EA , the output of the comparator 531 531c outputs signal 1.

The asynchronous Ti value calculation circuit 522 calculates the valve opening time Ti based on the absolute pressure P _B value and the engine water temperature T _W in synchronization with the clock pulse signal input from the clock generation circuit 521, and sends a corresponding signal via the AND circuit 530. and is added to the asynchronous Ti value control circuit 534. This asynchronous Ti value control circuit 534 operates the OR circuits 515a to 515a for a predetermined time according to the valve opening time Ti.
Injector drive circuit 516a~ via 15d
516d to open the main injectors 602a to 602d in the same manner as described above. Ti _(M) value control circuits 514a to 514d and asynchronous Ti control circuit 534 simultaneously control valve opening time Ti _(M) ,
When a signal corresponding to Ti is output, the valve opening time of the main injectors 602a to 602d follows the longer valve opening time.

The comparison circuit 520a receives Δθn by the TDC synchronization signal.
The difference Δθ (=θn−θn ₋₁ ) between the previous throttle valve opening θn _-1 and the current throttle valve opening θn output from the value register 510 is compared with a predetermined acceleration judgment value G ⁺ , and Δθ >G ⁺ , it is determined that it is an acceleration, and a signal is output and added to the synchronization Ti _(M) value calculation circuit 503. The comparison circuit 520b also compares the difference value Δθ output from the Δθn value register 510 with a predetermined acceleration determination value G _A ,
When Δθ>G _A , it is determined that it is an acceleration, and a signal is output and added to the asynchronous Ti calculation circuit 522.

The synchronous Ti _(M) value calculation circuit 503 and the asynchronous Ti calculation circuit 522 are the correction coefficient calculation circuit 5 shown in FIG.
40, the cooling water temperature increase coefficient K _TW uses the above formula.
Calculate the cooling water temperature increase coefficient K _TWT during acceleration based on (6). The circuits 503 and 522 correct the acceleration fuel increase constants T _ACC , Ti _A when the signal 1 is input from the comparison circuits 520 a and 520 b, that is, when the engine is in an accelerating state, and calculate the corrected constants T' _ACC , T' i Calculate the valve opening time Ti _(M) and Ti using _A. That is, the subtraction circuit 541 of the correction coefficient calculation circuit 540 calculates the correction coefficient according to the engine water temperature _TW .
The calculation (K _TW-1 ) is performed using K _TW and the value 1 inputted from the memory 542, and the corresponding signal is added to the multiplication circuit 543. The multiplication circuit 543 uses the coefficient input from the memory 544 as the input value (K _TW-1 ).
It multiplies C _TWT and performs the calculation of C _TWT × (K _TW-1 ), outputs a corresponding signal, and adds it to the adder circuit 545. The adder circuit 545 inputs the value C _TWT (K _TW-1 )
Add the value 1 input from the memory 542 to
Calculate K _TWT (=C _TWT (K _TW-1 ) + 1) and output the corresponding signal. In this way, the correction factor K _TWT
Calculate. Next, in the multiplication circuit 546, the fuel increase constant T _ACC during acceleration described above is multiplied by the correction coefficient K _TWT to obtain the value T' _ACC (=T _ACC ×K _TWT ), T'i _A
(= Ti _A × K _TWT ) is calculated. This multiplication circuit 54
6 outputs signals corresponding to the calculated values T' _ACC and T'i _A.

On the other hand, as is clear from the previous equation (6), the coefficient K _TWT >
K _TW , therefore, T' _ACC > T _ACC , T'i _A > Ti _A , and the fuel injection amount is increased by the increase.
Therefore, during acceleration when the vehicle is cold, a larger amount of fuel can be injected than when accelerating when the vehicle is warmed up, and acceleration performance is improved.

As explained above, according to the present invention, the cooling water temperature increase coefficient during acceleration (K _TWT > K _TW ) is calculated using the cooling water temperature increase coefficient other than acceleration (K _TW ), and the acceleration fuel increase constant T during warm-up is calculated. _ACC , Ti _A is multiplied by the cooling water temperature increase coefficient (K _TWT ) during acceleration to obtain the constant T _ACC ,
Since more fuel is injected than the amount increased by Ti _A , acceleration performance in cold conditions can be improved and smooth acceleration control can be performed.

In addition to acceleration, the increase coefficient K _TW also depends on the engine temperature.
Since it is set according to T _W and engine load P _B ,
The increase coefficient K _TWT during acceleration also has a value according to the engine load. Therefore, it is possible to increase the amount of fuel, taking into account the influence of fuel adhering to the intake pipe, which changes depending on the engine load, especially during cold acceleration, and it is possible to further improve acceleration performance.

Furthermore, focusing on the fact that there is a strong correlation between the degree of fuel increase required during steady operation when the engine is warmed up and the degree of fuel increase required during cold acceleration, the fuel increase coefficient during acceleration was determined. Since K _TWT is determined as a function of the increase coefficient K _TW for factors other than acceleration, a relatively simple circuit can be used to determine the increase coefficient during acceleration.
K _TWT can be calculated, and the configuration of the control device can be simplified.

In other words, if the increase coefficient K _TWT during acceleration is not determined as a function of the increase coefficient K _TW for purposes other than acceleration, K _TWT is determined according to the engine temperature T _W and the engine load P _B.
A table for determining the value (see Figures 4 and 5) is required, which requires an increase in memory capacity, and a program for calculating the K _TWT value (see 12 in Figure 2) is required. It may also be necessary to add.
(This also leads to an increase in memory capacity). In contrast, according to the present invention, the K _TWT value can be determined by a circuit 540 as shown in FIG.
1,545 and a multiplication circuit 543 (which can be realized with a relatively simple circuit), the apparatus as a whole can be simplified. Furthermore, in the case of a table search, it takes a lot of man-hours to input data to set each data value, test based on the input data, and modify the data values, but according to the present invention, in addition to the effect of reducing memory capacity, , simplification can be achieved in this respect as well. Note that even if the function of the circuit shown in FIG. 13 is implemented by software, it will be much simpler than a table search program that always involves interpolation calculations.

In addition, the acceleration increase correction is performed in synchronization with the engine rotation, and also at regular intervals asynchronously with the engine rotation, so that the increase correction during cold acceleration can be performed more appropriately, especially in the low engine rotation range. This makes it possible to further improve acceleration performance.

[Brief explanation of drawings]

Fig. 1 is an overall block diagram of the fuel supply control device of the present invention, Fig. 2 is a block diagram showing the overall program configuration of the control contents of the main and sub-injector valve opening times T _OUTM and T _OUTS in the ECU, and Fig. 3 The figure is a flowchart of the main program, and Figure 4 is the engine water temperature T _W and water temperature increase coefficient.
A table showing the relationship between K _TW and Figure 5 is water temperature T _W
Graph showing the relationship between the absolute pressure P _B and the water temperature increase coefficient K _TW when they are the same, Figure 6 is a flowchart of the subroutine for calculating the fuel increase constant T _ACC during acceleration in control synchronized with the TDC signal, Figure 7 is a curve of the two-time differential value ΔΔθ of the throttle valve opening θ, which is represented by the time t and the throttle valve opening θ, when the engine speed Ne is constant and the throttle valve opening Δθ is greater than ^a predetermined value G + Figure 8 shows the amount of change in throttle valve opening Δθn fuel increase constant during acceleration.
A table showing the relationship between T _ACC and FIG. 9 is a table showing the relationship between the number of TDC signal pulses N _PACC counted after acceleration and the fuel increase constant T _PACC after acceleration.
Figure 10 is a flowchart of the asynchronous acceleration subroutine, and Figure 11 is the amount of change in throttle valve opening Δθ _A
FIG. 12 is a block diagram showing an example of the internal configuration of the ECU shown in FIG. ₁ , and FIG. 13 is an example of a correction coefficient calculation circuit. FIG. DESCRIPTION OF SYMBOLS 1... Internal combustion engine, 5... ECU, 6... Fuel injection device, 11... Engine rotation speed sensor, 12... Cylinder discrimination sensor, 17... Starter switch, 502...
Synchronous Ti _(S) value calculation circuit, 503... Synchronous Ti _(M) value calculation circuit, 522... Asynchronous Ti value calculation circuit, 514a~
514d...Ti _(M) value control circuit, 534...Asynchronous Ti
Control circuit, 512, 516a to 516d... Injector drive circuit, 601, 602a to 602d...
Injector, 540... Correction coefficient calculation circuit, 55
0...Selection circuit.

Claims (1)

[Claims] 1. A fuel metering device that controls the amount of fuel supplied to the internal combustion engine is electrically controlled to determine the fuel injection amount, and an injection valve is driven in accordance with this injection amount to control the engine. In the fuel supply control method for controlling the amount of fuel supplied to A cold correction coefficient of the engine for correcting the injection amount is obtained, a cold correction coefficient at the time of acceleration is determined as a function of the cold correction coefficient, and engine acceleration is detected. A fuel supply control method during acceleration of an internal combustion engine, wherein the basic fuel injection amount is corrected using a correction coefficient, and the corrected basic fuel injection amount is output. 2 The cold correction coefficient during acceleration, which is a function of the cold correction coefficient, is calculated based on the formula K _TWT = C _TWT (K _TW −1) + 1.0, where K _TWT is the cold correction coefficient during acceleration. The method of controlling fuel supply during acceleration of an internal combustion engine according to claim 1, wherein the coefficient K _TW is a cold time correction coefficient and C _TWT is a constant larger than 1. 3 The fuel metering device that controls the amount of fuel supplied to the internal combustion engine is electrically controlled to determine the amount of fuel to be injected, and the injection valve is driven in accordance with this amount of injection to adjust the amount of fuel to be supplied to the engine. In the fuel supply control method, a synchronization signal synchronized with a predetermined crankshaft angular position of the engine is detected, a basic fuel injection amount according to the operating state of the engine is determined in synchronization with the synchronization signal, and the basic fuel injection amount is determined according to the operating state of the engine. Determines the fuel increase reference value according to the engine operating condition using a constant cycle asynchronous signal that is output independently of the position.
The engine temperature and engine load are detected, and the engine cold time correction coefficient for correcting the basic fuel injection amount is obtained based on the engine temperature and engine load, and the cold time correction coefficient during acceleration is corrected as a function of the cold time correction coefficient. determine a coefficient, detect acceleration of the engine, correct the basic fuel injection amount and the fuel increase reference value with the cold correction coefficient at the time of acceleration, and adjust the basic fuel injection amount and the fuel increase reference value in synchronization with the synchronization signal. A method for controlling fuel supply during acceleration of an internal combustion engine, comprising outputting a fuel injection amount and outputting the corrected fuel increase reference value in synchronization with the asynchronous signal.