JPS59200025A - Controller for supply quantity of fuel to internal- combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for controlling the amount of fuel supplied to an internal combustion engine,
In particular, the present invention relates to a device having a feature of controlling a fuel increase value during acceleration.

As a fuel increase control method during acceleration of an internal combustion engine, there is a method in which the acceleration increase value is variably controlled according to the acceleration state, for example, the opening speed of the throttle valve, etc., and the acceleration increase value is corrected according to the cooling water temperature. be.

According to this type of fuel increase control method, more fuel than necessary is supplied especially during sudden acceleration in a cold state, which may cause smoldering and fouling of the spark plug, as well as deterioration of the fuel consumption ratio. If the correction coefficient based on the cooling water temperature is changed so that the amount of fuel increases to an appropriate amount during sudden acceleration, the increase in fuel amount becomes insufficient during slow acceleration. On the other hand, if the correction coefficient is set so as to ensure satisfactory driving characteristics during slow acceleration, the amount of fuel increases too much during sudden acceleration as described above. That is, according to the above-mentioned increase control, it is extremely difficult to control the increase values to appropriate values in both the large increase area such as sudden full-throttle acceleration and the small increase area such as slow acceleration when the engine is cold.

Therefore, the present invention solves the above-mentioned problems,
An object of the present invention is to provide an entire apparatus capable of controlling the fuel supply amount using an optimum fuel increase value during acceleration regardless of the state of acceleration.

The configuration of the present invention that achieves the above-mentioned object will be explained using FIG. means C for determining the value; means d for limiting the determined fuel increase value to below the upper limit; and means e for increasing the amount of fuel supplied to the engine during acceleration operation according to the limited fuel increase value.
The device M of the present invention is equipped with the following.

The present invention will be described in detail below with reference to Examples.

FIG. 2 schematically shows an example of an electronically controlled fuel injection type internal combustion engine as an embodiment of the present invention. In the figure, 10 represents the engine body, 12 represents an intake passage, 14 represents a combustion chamber, and 16 represents an exhaust passage. The flow rate of intake air taken in through an air cleaner (not shown) is controlled by a throttle valve 18 that is linked to an accelerator pedal (not shown). The intake air that has passed through the throttle valve 18 is guided to the combustion chamber 14 via the surge tank 20 and the intake nearer 122.

A pressure takeout port 24a is opened in the intake passage downstream of the throttle valve 18, for example in the surge tank 20, and communicates with a pressure sensor 24 that detects the total absolute pressure in the intake pipe and generates a voltage corresponding to the detected value. are doing. The output voltage of this pressure sensor 24 is connected to the control circuit 2 via a line 26.
I will send it to 8th grade and it will be suitable.

The fuel injection valve 30 is actually provided for each cylinder, and is controlled to close once in response to an electric drive pulse sent from the control circuit 28 via a line 32, and is controlled to close once from a fuel supply system (not shown). The pressurized fuel sent is intermittently injected into the intake passage 12 near the intake valve 22.
') The exhaust gas after being combusted in the combustion chamber 14 is discharged into the atmosphere via the exhaust valve 34 and the exhaust passage 16, and further via the catalytic converter 36.

A crank angle sensor 40.42 provided in the distributor 38 detects a crankshaft (not shown) at 30.3.
Every 60 revolutions, a 4-speed signal is output, and the i4 signal for every 30 crank angles is sent to the control circuit 28 via a line 44, and the 4-speed signal for every 180 crank angles is sent to the control circuit 28 via a line 46. It will be done.

The output voltage of a throttle position sensor 48 connected to the shaft of the throttle valve 18 and generating a voltage according to the rotation angle of the shaft and therefore according to the opening degree of the throttle valve 18 is sent to the control circuit 28 via a line 50. You can get the appropriate size.

The output voltage of the water temperature sensor 52, which is attached to the cylinder block of the engine and generates a voltage according to the cooling water temperature, is on the line 5.
4 to the control circuit 28.

FIG. 3 is a block diagram showing an example of the configuration of the control circuit 28 shown in FIG. In the figure, the pressure sensor 24, the throttle position sensor 48, the water temperature sensor 52, the crank angle sensors 40 and 42, and the fuel injection valve 30 provided for each cylinder are each represented by blocks.

The output voltages of the pressure sensor 24, throttle body sensor 48, and water temperature sensor 52 are sent to a converter 60, which has an analog multiplexer function, and are converted to 11@ in response to an instruction signal from a microprocessor (MPU) 62.
Next, it is selected and A/D converted, resulting in two communication signals.

The signal from the crank angle sensor 40 every 30 degrees of crank angle is transmitted through the input/output circuit (I10 circuit) 64
It is sent to the PU62 and becomes an interrupt request signal for the crank angle 30 interrupt processing routine, and the I/? ) serves as a clock for incrementing the timing counter provided in the circuit 64. The signal from the crank angle sensor 42 for every 180 crank angles serves as a reset signal for the timing counter. +I obtained from this timing counter
(The injection start timing signal is sent to the MPU 62 and becomes an interrupt request signal for the injection pair processing interrupt routine.

Input/output circuit (1 or circuit) 66 includes A4PTJ 62
From 1! , receives a 1-bit injection signal with a wait time while adjusting the injection pulse width TAU to an appropriate value, and -7'1. A drive circuit is provided to replace all 11 drive drjs. A drive signal from the dynamic circuit 17 is sent to the fuel injection valve 30 and energized accordingly.

As a result, an amount of fuel is injected in accordance with the pulse width TAU.

The A//D converter 60 and the diagonal circuits 64 and 66 are
MPU62, which is the main component of a microcomputer,
It is connected to a random access memory (RAM) 68 and a read only memory (ROM) 70 via a path 72, and data is transferred via this bus 72.

In the ROM 70, a main processing routine program to be described later, an interrupt processing routine program for each crank angle 30, and other programs are stored in advance, as well as data and tables used in these calculation processes.

Next, the operation of the above-mentioned microcomputer will be explained using the flowcharts shown in FIGS. 4 to 6.

When the MPUf'+2 receives a pulse signal every 30 degrees of crank angle from the crank angle sensor 40, it executes the interrupt processing routine shown in FIG. 4 to form data representing the rotational speed NE'4 of the engine. That is, in step 80, all values of the free run counter provided in the MPU 62 are read and the value is set as C3o. Next, in step 81, the difference ΔC between the value cso' read during the previous crank angle 30° interrupt processing and the current value CaO is calculated.
is calculated from ΔC-C3o-C3o', and in the 19th step 82, the reciprocal of the difference ΔC 'ff: is calculated to obtain the rotational speed NE.

That is, the calculations NE←, llIC are performed. However, A is a constant. The NE obtained in this way is RAIM6
8 is stored in a predetermined position. In the next step 83, the calculation process of C30'←C30 is performed so that the current counter value C3ok is used as the previous read value in the next interrupt process. Thereafter, after executing the necessary processing, this interrupt processing routine is terminated and the process returns to the main processing routine.

The N-digital converter 60 receives an A/D conversion start instruction at regular intervals and performs conversion for each channel. When the A/D conversion is completed, a conversion completion interrupt is requested from the MPU 62, and binary data corresponding to the output voltage of the pressure sensor 24, the output voltage of the throttle position sensor 48, and the output voltage of the water temperature sensor 52 are thereby generated. PM, TAAD,
It's like TI numbness.

It is stored in the RAM 68. If a conversion completion interrupt occurs in the channel of the throttle position sensor 48, the binary data converted this time is stored as TAAD, and the binary data converted last time is stored as TAOLD.
It is stored in 8.

The MPU 62 executes the process shown in FIG. 5 in the middle of the main processing routine to calculate the fuel injection pulse width TAU' (i: ~ Calculate the difference ΔTA between the throttle valve opening T and the h obtained by the transformation. That is, ΔTA = TAAD-TAO
LD) Perform calculations. Since TAOLD represents the throttle valve opening a certain time before TAAD, ΔTA represents the opening/closing speed of the throttle valve. In the next step 9], by determining whether or not this ΔTA is greater than or equal to zero, it is determined whether or not the throttle valve 18 has rotated in the opening direction, in other words, whether or not it has moved in the acceleration direction. "No" pigpen, that is, ΔTA (If it is 0, it is not acceleration, so proceed to step 92 and perform basic injection) 8
Calculate the pulse width TPO. If “YES”, that is, Δ
If TA≧O, it is assumed that the system is in an acceleration state, and the process proceeds to step 93, where the warm-up correction coefficient KTCI at the time of acceleration is stored in the RAM 68 and determined from the cooling water temperature THIIV. R.O.
A one-dimensional function table of KTCI for il''I TBV is stored in advance in M 70, and in step 93, KTCI for n items is obtained using an interpolation method etc. Note that instead of using the function table, an algebraic expression KTCJ for TI(W may be obtained by

In the next step 94, it is determined whether or not the throttle opening speed ΔTA is greater than a predetermined value B, and it is determined whether or not to increase the acceleration amount based on the throttle opening speed.

If ΔTA≧B, the opening speed of the throttle valve 18 is large, so proceed to step 95 and throttle.
The accelerated color addition value FTCTA is calculated by ΔTA(B, in which case step 95 is skipped and the process proceeds to step 96.

In step 95, an acceleration increase value FTCTA is calculated from the throttle opening speed ΔTA and the warm-up correction coefficient KTCI using the following equation. However, 2 in K11 is a constant.

In the next step 96, the final acceleration increase value FTC is determined. This acceleration increase value FTC is the throttle valve 18
The increase value FTCLL when the is opened from the fully closed state, the increase value F'TCND when the shift position changes from the neutral range to the drive lens when the automatic transmission is fully equipped, the acceleration increase value based on the amount of change in the pressure inside the intake pipe It is set to the maximum value of FTCPM and the above-mentioned acceleration increase value FTCTA based on the throttle opening speed. That is, in step 96, FTCLL, F
A selection is made of the maximum value among TCND, FTCPM, and FTCTA. Note that the process of step 96 is not essential to implementing the present invention.

For example, FTCLT.

F' without using increased values such as FTCND, FTCPM, etc.
TCTA may be used as FTC.

In step 97, acceleration increase - upper limit value FTC of hitting value FTC
I'1m1t is calculated. This FTcl imit
may be an identified value, but it is preferable to make it variable according to the warm-up correction coefficient KTCI and therefore the cooling water temperature T history.

Stella 7'97 u FTCI += t'rFTC1
imi t- is calculated from 3 + K 4 X KTC1. However, K3 + K4 is a constant. Stella f9B and 99 limit the acceleration increase value FTC obtained in step 96 to be equal to or less than FTC1imit.

In the Stella 7″92, the basic injection pulse width TP is calculated from the rotational speed NE and the intake pipe internal pressure PM using a well-known method, for example, NE
, a two-dimensional function table of TP for PM or N
It is obtained from a method using a one-dimensional function table such as E-TP and PM-TP.Next step 10
0, the final fuel injection pulse width TAU is calculated according to the following formula from the basic l injection/gurus@TP, the acceleration increase value FTC1 and other correction coefficients α and β, and the invalid injection time TV of the injection valve 30. Ru.

TAU = TP - FTC・α+β+TV The data regarding the injection pulse width TAU calculated in this way is:
In the next step 101, the data is stored in a predetermined location in the RAM 680.

Acceleration increase value FTCLL, FTCND of each story mentioned above
.

FTCPM, 'FTCTA will be attenuated over time if the conditions for increase are no longer met. Attenuation of the acceleration increase value FTCTA based on the throttle opening speed is performed, for example, by a routine as shown in FIG. The routine shown in FIG. 6 is executed during the main routine or during an interrupt routine executed at predetermined time intervals or at predetermined crank angles. First, in step 110, the throttle opening speed Δ
TA is compared with a predetermined value B to determine whether the increase condition is exceeded. In the case of ΔT♀B, the following processing is directly skipped. If ΔTA<B, proceed to step 111 and FTC
k is decreased by a constant value. Ste, Zo 112 and 113
This is a step to prevent HFTC-AE negative Kfx. According to the process shown in FIG. 6, the FTC is attenuated to zero when the acceleration condition is exceeded. Other increase value FTCLL.

The attenuation operations of FTCND and FTCPM are also similar to those in Fig. 6.

Methods 1d:fm are known for creating an injection/phraseless signal having a duration corresponding to TAUK from the o1 pulse width TAU using the processing routine shown in FIG. For example, when the injection start timing signal is generated, the TA inverts the injection signal to the pulse signal i ``i'' and informs the value of the above-mentioned free run counter at that time.
The value of this counter after U has elapsed is set in the all-contain register. Generates an interrupt when the value of the free run counter becomes equal to the set value of the consolidation register,
11? 1. The signal is inverted to n On, thereby forming an injection pulse signal with a duration corresponding to TAU.The injection start timing signal is generated by the interrupt every 30 degrees of crank angle as shown in Fig. 4. It is formed every time this interrupt processing routine is executed a predetermined number of times in the processing routine.

FIG. 7 is a diagram for explaining the present invention in detail, (A
) represents the vehicle speed, (B) represents the acceleration increase value FTC, and (C) represents the time characteristics of the cooling water temperature TfFIJ. The acceleration increase value FTC is controlled according to the degree of acceleration such that it is large in the case of sudden acceleration and small in the case of slow acceleration, and is then attenuated. According to the present invention, the upper limit of the acceleration increase value is limited by the upper limit FTC1imit. In the same figure (n), the solid line represents the present invention, and the broken line represents FTCi according to the prior art. In this way, the upper limit value FT
By providing C1imj t, FTC during slow acceleration
Even if the warm-up correction coefficient KTCI is set to be sufficiently large to improve driving characteristics, excessive fuel supply will not occur because FTC during rapid acceleration is limited by the upper limit value FTCl imit. In addition, as shown in FIGS. 3(B) and 3(C), by making the upper limit value FTC1imit variable in accordance with the cooling water temperature THW, more desired control becomes possible. In other words, if FTClimit is constant regardless of water temperature, FTC will be stuck at the upper limit even when accelerating slowly at low water temperatures, and will not reach the upper limit even when accelerating rapidly at high water temperatures. It's FTCl
All of this can be prevented by making imit variable as described above. In this case, the cooling water temperature TI (w
The 8th M represents the characteristics of the upper limit value "C11m1t" for "C11m1t".
is large, and as THW increases, TClimit decreases, and when THW exceeds a certain temperature, FTClim
it becomes constant.

As explained in detail above, according to the present invention, the acceleration increase Y value set depending on the acceleration state is limited to below the upper limit value, so the setting is made so as to give a sufficient acceleration increase Y during slow acceleration. However, there is no risk of excessive acceleration increase during sudden acceleration, and it is possible to always perform optimal acceleration increase. As a result, it is possible to prevent the spark plug from smoldering and fouling during sudden acceleration in warm cedar wood, improve fuel efficiency, and improve driving performance during slow acceleration.

4. Brief explanation of the drawing
'1 Fig. 1 is a diagram showing the configuration of the present invention, Fig. 2 is a schematic diagram of an embodiment of the invention, Fig. 3 is a block diagram showing details of the control circuit in Fig. 2, and Fig. 4 is a diagram showing the configuration of the present invention. 1 is a flowchart of a part of the control program of the control circuit shown in FIG. 3, and FIG. 7 is a detailed explanation of the present invention.
FIG. 8 is a characteristic diagram of the acceleration increase limit value versus cooling water temperature.

18... Throttle valve, 24... Pressure sensor, 28
...Control circuit, 30...Fuel injection valve, 40.42.
...Crank angle sensor, 48...Throttle 2 position sensor, 52...Cooling water temperature sensor, 60...A/
D converter, 62...MPU, 64, 66...
Engineering circuit, 68...RA 1170 ROM.

patent applicant Toyota Motor Corporation patent application agent Patent attorney Akira Aoki Patent attorney Kazuyuki Nishidate Patent attorney Akiyuki Yamaguchi 1st

Claims (1)

[Scope of Claims] 1. means for detecting an acceleration state of an engine; means for determining an increased amount of fuel to be additionally supplied to the engine in accordance with the detected acceleration state; 1. A fuel supply amount control device for an internal combustion engine, comprising means for limiting the amount of fuel to below an upper limit value, and means for increasing the amount of fuel supplied to the engine during acceleration operation according to the fuel amount increase value after the limit. 2. The fuel supply amount control device according to claim 1, wherein the limiting means includes means for detecting the engine cooling water temperature and means for varying the upper limit value according to the detected cooling water temperature. 3. The fuel supply amount control device according to claim 2, wherein the upper limit value variable means increases the upper limit value when the cooling water temperature is low compared to when it is high.