JPS59190435A - Fuel injection control device of internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve the acceleration performance from the fully-closed condition by performing more warm-up augmentation correction as compared with the condition other than the fully-closed condition when an intake air throttle valve is fully closed. CONSTITUTION:Signals of the rotating speed, load, temperature of an engine and the throttle valve opening are fed to a control circuit performing the fuel injection control. The basic Fuel injecton time is calculated based on the engine rotating speed and engine load. furthermore, the warm-up augmentation coefficient is calculated based on the engine temperature, and the final fuel injection time is calculated by correcting the basic fuel injection time calculated based on the warm-up augmentation coefficient calculated when the fully-closed condition is not detected by the full-closure detection means of an intake air throttle valve. Accordingly, when the full-closure condition of the intake air throttle valve is not detected by a full-closure detection means, the final injection time is calculated so as to be further augmented after correction, and an injection signal corresponding to this calculated final injection time is fed for fuel injection. During the warm-up augmentation correction, more worm-up augmentation correction is performed as compared withthe condition other than the fully-closed condition when the intake air throttle valve is in a fully-closed condition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection control device for an internal combustion engine, and in particular, to a fuel injection control device for an internal combustion engine, and in particular to a fuel injection valve provided in an intake passage, and a fuel-air mixture injected from the injection valve and mixed with intake air to be used for engine combustion. Fuel injection control for an internal combustion engine, which has a relatively long intake passage leading to the engine compartment, and determines the increase in fuel amount during engine warm-up depending on whether the intake throttle valve is fully closed or not. It is related to the device.

In such an electronic fuel injection control device for an internal combustion engine, the basic fuel injection time, that is, the basic opening time of the injection valve is calculated based on, for example, the absolute pressure in the intake pipe and the engine speed, and the basic fuel injection time is On the other hand, the final fuel injection time is determined by performing various correction calculations depending on the operating state of the engine, including the warm-up state and transient state of the engine.

Correction according to the warm-up state of the engine is generally called warm-up increase correction. For example, when the engine cooling water temperature is 70°C or less, warm-up increase correction is performed according to the water temperature as follows. . First, measure the engine coolant temperature, look up the warm-up increase coefficient, which is determined to decrease as the engine coolant temperature increases, from the measured engine coolant temperature, and calculate the warm-up increase coefficient for the basic fuel injection time. The final injection time is calculated by multiplying by

However, in the conventional warm-up increase correction,
Even when the intake throttle valve is fully closed, the same correction process is performed as when it is not fully closed.

Therefore, when accelerating from a fully closed state of the intake throttle valve, even if the amount of warm-up acceleration is increased in accordance with the amount of acceleration of the engine, the fuel may be insufficient, and the engine may become sluggish or sluggish. In particular, in an internal combustion engine where the injection valve and the combustion chamber are relatively far apart as described above, and when the engine acceleration amount is calculated according to the change in intake pipe pressure, the change in intake pipe pressure is Since the change in the opening of the intake throttle valve and p also appear with a slight delay, acceleration performance in particular tends to be a problem.

In addition, when increasing the amount for acceleration, if the amount is increased by a large amount in consideration of the driving performance during acceleration from the fully closed state, an overrich condition will occur when accelerating when not in the fully closed state.

The purpose of the present invention is to solve such problems and improve the acceleration performance from the fully closed state of the intake throttle valve, in order to improve the acceleration performance from the fully closed state of the intake throttle valve. An object of the present invention is to provide a fuel injection control device for an internal combustion engine that performs a large number of warm-up increase corrections.

The present invention includes a first calculating means for calculating a basic fuel injection time based on the engine speed detected by the engine speed detecting means and the engine load detected by the engine load detecting means, and an engine temperature detecting means. A second calculating means calculates a warm-up increase coefficient based on the detected engine temperature, and a second calculating means calculates a warm-up increase coefficient when the fully closed state of the intake throttle valve is not detected by the fully closed detecting means detects the fully closed state of the intake throttle valve. The final fuel injection time is calculated by correcting the basic fuel injection time calculated by the first calculation means based on the warm-up increase coefficient calculated by the calculation means, and the final fuel injection time is calculated by the fully closed detection means. a correction means for correcting the final injection time by further increasing the final injection time after the correction when a fully closed state is detected; and an injection signal corresponding to the final injection time calculated by the correction means. and a signal generating means for supplying the fuel to the fuel injection valve.

In the present invention, during the warm-up increase correction, when the intake throttle valve is fully open, the increase due to the warm-up increase correction is performed more often than when the intake throttle valve is not fully open.

If the acceleration performance is improved by optimally increasing the amount of acceleration when accelerating with the intake throttle valve fully closed, it will become automatically rich when accelerating with the intake throttle valve not fully closed, but the present invention However, the acceleration performance from the fully closed intake throttle valve can be improved without causing such problems.

The above-mentioned additional increase when the intake throttle valve is fully opened is performed based on a starting temperature correction value that increases as the engine temperature at engine startup is lower and that is attenuated as time m1 elapses after engine startup. is preferred.

The present invention will be explained below based on the drawings.

FIG. 1 shows a configuration example of an internal combustion engine for an automobile to which an electronic fuel injection control device according to the present invention is applied. The air filter 1 is connected to a throttle body 5 via an inlet nozzle 3. The throttle body 5 is provided with a fuel injection valve 7 on its upstream side, and an intake throttle valve 9 is provided downstream of the fuel injection valve 7 to adjust the amount of intake air in conjunction with an accelerator pedal (not shown). An intake pipe absolute pressure sensor 11 is provided downstream of the intake throttle valve 9 to measure the absolute pressure at that location. Furthermore, there is a valve opening position sensor 2 that measures the opening position of the intake throttle valve 9, an idle switch 4 that is turned on only when the intake throttle valve 9 is fully closed, and a valve opening position sensor 2 that measures the opening position of the intake throttle valve 9. A power switch 6, which is turned on only when the temperature is 40 degrees or higher, is installed in association with the intake valve 9.

The throttle body 5 is connected to an intake manifold 13 having branch pipes connected to each cylinder of the engine,
The intake manifold 13 has an intake air temperature 'e
An intake air temperature sensor 15 is provided to measure the air temperature. On the bottom wall 13a of the intake manifold 13 before branching, there is a riser part 1 for circulating engine cooling water and heating the air-fuel mixture.
7 is provided.

Reference numeral 19 designates a well-known engine body, in which a combustion chamber 2 is formed by a piston 21, a cylinder 23, and a cylinder rad 25.
7 is defined, and the combustion chamber 2 is
The air-fuel mixture sucked into the fuel tank 7 is ignited by the spark plug 31. A water jacket 33 is formed around the cylinder 23, and engine cooling water is circulated through the walk jacket 33 to cool parts including the cylinder 23.

An engine coolant temperature sensor 37 is provided on the outer wall of the cylinder block 35 to measure the temperature of the engine coolant in the water jacket 33.

An exhaust manifold 39 is connected to the exhaust boat (not shown) of the shilling head 250, and an 02 sensor 41 for measuring the residual oxygen concentration in the exhaust gas is provided downstream of the exhaust manifold 39. The exhaust manifold 39 is connected to an exhaust pipe 45 via a three-way catalyst 43.

47 is a transmission connected to the engine body 19;
A vehicle speed sensor 49 is attached to measure the speed of the vehicle based on the rotational speed of the final output shaft.

Further, 51 is a key switch, 53 is an igniter, and 55 is a distributor. The distributor 55 is provided with an Ne sensor 57 that outputs an on/off signal at every predetermined crank angle θ1, and the output signal determines the engine rotational speed. It is possible to know the predetermined crank angle position, and also to turn on and off at every angle θ2, which is larger than the above angle θ1.
A G sensor 59 that outputs an off signal is provided, and the output signal is used to determine the cylinder and to detect the top dead center position.

Further, 60 indicates a battery.

The control circuit 61 includes a valve opening position sensor 2. Idle switch 4. Power switch 6, intake pressure sensor 11, intake temperature sensor 15. Engine coolant temperature sensor 37, 02 sensor 4
1. Vehicle speed sensor 49. Key switch 51. Ne sensor 5
7. The G sensor 59 and the battery 60 are connected to each other, and the valve opening signal SL, idle signal S2. Power signal S3, intake pressure signal S4. Intake temperature signal S5. Water temperature signal S6. Air-fuel ratio signal S7. Vehicle speed signal S8. Start signal 8
9. Engine speed signal S10. A cylinder discrimination signal Sll and a battery voltage signal 814 are input from each sensor. The control circuit 61 is still connected to the fuel injection valve 7 and the igniter 5.
3, and outputs a fuel injection signal S12 and an ignition signal S13 based on predetermined calculations.

As shown in FIG. 2, the control circuit 61 includes a central processing unit (CPU) 61a that controls various devices.

Random access memory (RAM) 61c, in which various numerical values and programs are written in advance, - only memory (ROM) 6lb, numerical values and flags for calculation processes are written in predetermined areas, converts analog input signals into digital signals A/D converter (ADC) 61 to convert
d. Input/output interface (Ilo) 6 i to which various digital signals are input and various digital signals are output.
e. Backup memory (BU-RAM) 61 that receives power from the auxiliary power source and retains memory when the engine is stopped.
f, and path lines 61g to which these devices are respectively connected. The program described below is RO
It is written in M61b in advance.

In the engine described above, fuel is injected according to the flowchart shown in FIG. Referring to Figure 3,
In step P1, the engine speed Ne is read based on the engine speed signal S1, which is a reference position signal, and the intake pipe pressure P M f is read based on the intake pipe pressure signal S4.
:H included. In step P2, the basic injection time TP is determined based on the rotational speed Ne and the intake pipe pressure PM from the map shown in FIG. Find the injection time τ.

Here, the corrected injection time 7 is determined by the correction calculation process in step P3.
is generally determined by the following formula.

τ=TPXF'WLXFAFX (1+FTC) ×F
THA... (1) Where: TP - Basic fuel injection time FWL - Warm-up increase coefficient FAF - Air-fuel ratio feedback correction coefficient FTC = Transient air-fuel ratio correction coefficient FTHA - Intake temperature correction coefficient Therefore, Fig. 5 The injection time τ is obtained by calculating each coefficient based on the τ calculation routine shown in FIG.

That is, first, step P11-(: warm-up increase coefficient FW
Executes arithmetic processing of L.

That is, referring to FIG. 6, in step P21 the water temperature TH
W is read, and in step P22, the water temperature T shown in FIG.
From the map of HW and warm-up correction coefficient FWLφ, the warm-up correction coefficient FWLφ is looked up based on the read water temperature TH'W and is temporarily stored in a predetermined area, and the process proceeds to step P23. In step P23, it is determined based on the idle signal S2 from the idle switch 4 whether the intake throttle valve 9 is fully closed. In this embodiment, the idle switch 4 is closed when the intake throttle valve 9 is fully closed, so if the idle switch 4 is closed, in other words, turned on, this step P23 is determined to be affirmative, and the switch is turned off. If it is, it will be judged as negative.

When the intake throttle valve 9 is fully closed and the process proceeds to step P24, in this step P24, the correction value
At step 22, the correction value
Jump to 12.

If the intake throttle valve 9 is not fully closed, proceeding to step P26, the correction coefficient FWLφ calculated in step P22 is stored in a predetermined area as the warm-up increase coefficient FWL, and this calculation routine is terminated, as shown in FIG. Jump to step P12.

The feedback correction coefficient FAF in step P12 in FIG. 5 can be calculated based on the air-fuel ratio signal S7 from the 02 sensor 41 using a well-known technique. In addition, the transient air-fuel ratio correction coefficient FTC in step P13 can be calculated, for example, by calculating the change in intake pressure based on the intake pressure signal S4 from the intake pipe pressure sensor 11, and calculating it according to the amount of change. Furthermore, the intake temperature correction coefficient F T HA in step P14 is performed to compensate for the density of intake air that varies depending on the temperature, and is calculated by adding a predetermined value (direct k) to the digital value of the intake air temperature T HA. These steps P12
~P14 is not directly related to the present invention, so a detailed explanation will be omitted.

When these arithmetic operations are completed, TPXF is
'WLXFAFK(1+FTC)×FTI(A is calculated to calculate the corrected injection time τ, stored in the RAM 61C, and jumps to step P4 in FIG. 3.

In step P4 of FIG. 3, compensation is performed using the battery voltage.

That is, referring to FIG. 8, in step P31, the battery voltage BV is read based on the battery voltage signal S14, and in step 111t P32, the battery voltage B is read.
Based on V, a voltage correction coefficient τ■ is determined from a map of battery voltage BV and voltage correction coefficient τV shown in FIG. Then, in step P33, (τ+τV) is executed and after the final injection time, the injection signal S12 is output from the control circuit 61 to the injection valve 7, and the injection valve 7 is driven accordingly.

As described above, in the embodiment of the present invention, during warm-up increase correction in synchronous injection control, the warm-up correction coefficient FWLφ is determined based on the engine cooling water temperature, and if the intake throttle valve 9 is not fully closed, the warm-up correction coefficient FWLφ is used. Basic fuel injection time TP
If the intake throttle valve 9 is fully closed, a predetermined value The acceleration performance during the next acceleration can be improved.

Next, a case will be described in which the correction value X in step P125 is changed in accordance with the engine starting temperature and the elapsed time after starting.

When the correction value ADD calculation processing routine shown in FIG. 1O is activated at a predetermined timing, it is first determined in step P41 whether or not the engine is being started. This determination is performed based on the engine rotational speed signal SIO. If an affirmative determination is made, that is, if starting is in progress, in step P42, the starting intake air temperature TJ,(A is read as the engine starting temperature based on the intake air temperature signal S5 at that time.Next, in step P43, The 11th
From the map of correction value ADD and intake air temperature THA shown in the figure,
Correction value ADD based on the read starting intake air temperature THA
Load. In step P44, the read correction value A
It is determined whether a certain period for attenuating the DD by a predetermined number of sections has elapsed, and if an affirmative judgment is made, the process proceeds to step P45. In step P45, (ADD-α) is calculated and the result is stored in a predetermined storage area as a new correction value ADD.

Next, in step P46, it is determined whether the correction value ADD is smaller than zero, and if the judgment is affirmative, the correction value ADD is set to zero in step P47 and the ADD performance routine is ended, and if the judgment is negative, step P47 is skipped. and end ADD@calculation routine-chintan. When this routine is started after the engine has been started, a negative determination is made in step P41 and the process jumps to step P44. If an affirmative determination is made in that step, steps P45 to P47 are executed, and if a negative determination is made in that step, steps P45 to P47 are executed. P45 to P47 are skipped and the series of procedures ends.

As described above, the starting temperature correction value ADD read based on the intake air temperatures T and HA at the time of engine starting is attenuated in a certain number of sections at each predetermined period, as shown in FIG.

Here, the rate of increase in the wall surface temperature of the intake manifold 13 is measured in advance for each engine starting vortex layer by experiment, and the correction value ADD and the constant value are set so as to attenuate in accordance with the rate of increase in the wall surface temperature of the intake manifold 13. By setting this, when the intake throttle valve 9 is fully closed, an amount of fuel more suitable for the engine warm-up state can be supplied into the intake manifold 13, and acceleration from the fully closed intake throttle valve can be maintained. Performance is further improved.Such a correction is important because in the type of engine shown in Figure 1, the so-called SPI (single point injection) engine, the vaporization of the injected fuel is dependent on the wall temperature of the intake manifold. Particularly effective.

In the above, we will discuss the so-called SPI L (India Injection) engine in which only one fuel injection valve is provided upstream of the intake throttle valve.
It goes without saying that the present invention can also be applied to an engine in which the fuel injection valve and the engine combustion chamber are relatively separated. In the above, the basic fuel injection time TP is determined based on the engine speed and the intake pipe pressure, but the basic fuel injection time TP may also be calculated based on the engine speed and the intake air amount. Also,
Although the starting temperature correction value ADD is selected according to the intake air temperature THA at the time of starting, the cooling water temperature T' during engine starting
The selection may be made depending on HW, engine oil temperature, or cylinder block temperature. Furthermore, it is also possible to select a correction value depending on the water temperature, engine oil temperature, or cylinder block temperature during engine operation.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of an automobile internal combustion engine to which the present invention is applied, FIG. 2 is a detailed block diagram showing an example of its control circuit, FIG. 3 is a flowchart showing an example of a fuel injection procedure, and FIG. Figure 4 shows engine speed Ne and intake pipe pressure PM.
A diagram showing an example of a map for reading out the basic fuel injection time TP from
FIG. 7 is a graph showing the relationship between engine water temperature THW and warm-up correction coefficient FWLφ; FIG. 8 is a flowchart showing an example of calculation processing for final fuel injection time Fτ; The figure shows battery voltage BV
FIG. 10 is a flowchart showing an example of the procedure for determining the starting temperature correction value ADD, and FIG. 11 shows the relationship between the starting temperature T HA and the starting temperature positive value A , DD FIG. 12 is a graph showing the time decay of the starting temperature correction value ADD. 7... Injection valve, 9... Intake throttle valve, 11.
...Intake pipe pressure sensor, 13...Intake manifold. 15... Intake temperature sensor, 17... Riser section. 19...Engine body, 27...Combustion chamber. 33...Water jacket, 37...Engine coolant temperature sensor, 41...02 sensor. 49...Vehicle speed sensor, 51...Key switch. 53...Igniter, 55...Distributor. 57...Ne sensor, 59...G sensor. 61...Control circuit. Agent Tatsuyuki Unuma (and 7 others) Figure 5 Figure 4 [A Figure 6 Figure 7 Figure 8 Figure 9 Voltage [3V (V)] Figure 10 4 F45 -

Claims (1)

[Scope of Claims] (a) first calculation means for calculating a basic fuel injection time based on the engine rotation speed detected by the engine rotation speed detection means and the engine load detected by the engine load detection means; (b) a second calculation means for calculating a warm-up increase coefficient based on the engine temperature detected by the engine temperature detection means; and (C) a fully closed detection means for detecting a fully closed state of the intake throttle valve. When the fully closed state is not detected, the basic fuel injection time calculated by the first calculation means is corrected based on the warm-up increase coefficient calculated by the second calculation means, and the final fuel injection time is calculated. correcting means for calculating the final injection time by correcting the corrected final injection time so as to further increase the amount when the fully closed state of the intake throttle p-valve is detected by the fully closed detection means; (d) A signal generation means for supplying an injection signal to a fuel injection valve in accordance with the final injection time calculated by the correction means. A fuel injection control device for an internal combustion engine, comprising: 2. In the device according to claim 1, when the fully closed state of the intake throttle valve is detected by the fully closed detection means, the correction means adjusts the temperature according to the engine temperature at the time of starting the engine. The intake throttle valve is calculated when the intake throttle valve is not fully closed, based on a starting temperature correction value, which is selected based on the starting temperature correction value and is subtracted according to the elapsed time after starting, and which is a larger value as the engine temperature at starting is lower. A fuel injection control device for an internal combustion engine, characterized in that the final injection time is corrected to further increase the final injection time.