JPS58110838A - Engine fuel supply system - Google Patents

Abstract

PURPOSE:To make it possible to shorten the time of operation at a processor section and to control the flow rate of a fuel delicately by a method wherein data required for controlling the flow rate of the fuel are stored by ROM or RAM in advance and are read out in accordance with the operation condition of the engine. CONSTITUTION:A fuel flow rate control means 28 adopted to take in the outputs of a r.p.m. senser 1, a throttle valve opening degree sensor 2, an O2 sensor 4, a temperature sensor 5, a rotational change sensor 6 and an acceleraion sensor 7 so as to control an electromagnetic valve 23 at a fuel supply section in accordance with the operation condition of the engine is provided. The control means 28 is provided with first-third ROM 36-38, first-third RAM 39-41 and CPU 31 so that, for example, the ROM36 stors a value corresponding to the flow rate of the fuel meeting the engine r.p.m. and load and the ROM37 stores the coefficient of correction corresponding to the acceleration of the engine. Thus, when the engine is in operation, the data required for the control of the flow rate of the fuel are read out from the ROM 36-38 and the RAM 39-41 on the bases of the outputs of the above mentioned sensors and operated properly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel supply system for an engine, and more particularly to a fuel supply system for an engine in which the supply of fuel can be electronically controlled.

Various electronically controlled fuel supply systems for engines have been developed and put into practical use, but when attempting to perform fine-grained control, the responsiveness from sensor detection to appropriate fuel control is poor. Moreover, if the responsiveness is increased, fine-grained control cannot be performed.

The present invention attempts to solve these contradictory problems all at once, and aims to provide an engine fuel supply system that has good responsiveness and is also capable of fine-grained control. .

Therefore, the engine fuel supply device of the present invention includes a rotation speed detection section that detects the engine rotation speed, a load detection section that detects the engine load state, and an oxygen concentration detection section that detects the oxygen concentration in exhaust gas. It includes a detection section, an acceleration detection section that detects acceleration, and a fuel supply section that can supply fuel to the intake passage of the engine. Fuel flow rate supplied from the fuel supply unit
A fuel flow control means is provided to control the fuel flow rate), and the fuel flow control means has a first lead which stores a value corresponding to the fuel flow rate according to the engine speed and the engine load state. A memory and a second read memory that stores a correction coefficient value corresponding to acceleration are provided, and the first read memory is provided so that the fuel flow rate becomes the stoichiometric air-fuel ratio in a preset operating range. The correction coefficient value for correcting the signal from the memory is stored in the first drive/write memory, and the uh memory is stored in the drive/write memory 1 in other operating regions different from the above operating region. a second read memory capable of storing a correction coefficient value for correcting the signal from the first read memory so that the fuel flow rate becomes a predetermined air-fuel ratio other than the stoichiometric air-fuel ratio based on the correction coefficient value to be corrected; Equipped with write/write memory,
and.

Control of signal retrieval from each of the above detection units, data read control in the read memory, data write control or data read control of the read/write memory, signal output side am to the fuel supply unit, and appropriate calculations. It is characterized by having a processor unit that performs processing.

Hereinafter, embodiments of the present invention will be explained with reference to the drawings.
Figures 1 to 7 show a fuel supply system for an engine as a first embodiment. Figure 1 is an overall configuration diagram, Figure 2 is a block diagram, and Figure 3 is a detailed diagram of the fuel supply unit. FIG. 4 is an output characteristic diagram for explaining the effect.

FIG. 5 is a graph showing an example of engine speed fluctuations, FIG. 6 is a fuel consumption-air-fuel ratio characteristic diagram, and FIG. 7 is a block diagram including other control means.

As shown in FIGS. 1 and 2, a rotation speed detection section (rotation speed sensor) for detecting the rotation speed N of the engine E is provided.

Further, a throttle opening detection section (throttle opening sensor) 2 is provided as a load detection section, and this detects the load state M of the engine E based on the opening θ of the throttle valve 25.
can be detected.

Furthermore, an oxygen concentration detection section (02 sensor) 4 is provided that detects the oxygen concentration in the exhaust gas in the exhaust passage 3 of the engine E to detect air-fuel ratio information, and also includes the temperature of the engine E (for example, the cooling water temperature 'rw'). A temperature detection unit (temperature sensor) 5 is provided to detect the temperature of the oil.

Also, a rotational fluctuation detection unit (ΔN sensor) that detects rotational fluctuation ΔN of the engine E in response to a signal from the rotational speed sensor l.
6 is provided.

An acceleration detecting section (acceleration sensor) 7 is provided on the front panel, which receives a signal from the throttle opening sensor 2 and detects acceleration dθ/at (including deceleration). It is configured as a differentiation circuit that differentiates and outputs the signal from the sensor 2.

Additionally, as shown in FIGS. 1 and 3, a fuel supply section 9 for supplying fuel to the intake passage 8 of the engine E is provided.5This fuel supply section 9 is shown in FIG. 3 in this embodiment. It is constructed as a carburetor equipped with a variable venturi 10 like this.

That is, as shown in FIG. 3, a differential pressure responsive motor 11 is attached to the outer wall of the venturi portion of the carburetor.

Two chambers 13 separated by a diaphragm 12.
14, atmospheric pressure acts on one chamber 13, and the pressure (negative pressure) in the intake passage 8 acts on the other chamber 14.
The diaphragm 12 is displaced by the biasing force of the spring 15 in the diaphragm 12;

A mouth moving part 16 that protrudes or retracts toward the intake passage 8 is attached.

Note that a space 16a with a vent opening into the intake passage 8 is formed in the movable part 16, and this space l'cIt is provided in the diaphragm 12 to prevent ventilation from this space 16 to the chamber 14. and a check valve 17 that allows.

Via the orifice 1B provided in parallel with the check valve 17 in the diaphragm 12.

It communicates with the chamber 14.

Further, the chamber 13tri communicates with the atmosphere via a passage 19.

Furthermore, the movable part 16 has a needle valve 2 inserted into a nozzle opening 20 that opens in the venturi wall facing the movable part 16.
1 is installed.

In this way, the moving part 16 is displaced according to the pressure in the intake passage B, and the variable venturi 10 is configured.
The way the movable part 16 is displaced at this time is as follows:
It is adjusted so that the gas flow rate passing through Q'i is always approximately constant.

Note that a potentiometer PM used for feedback control of the position of the variable venturi 10 is attached to the motor 11;
M can be omitted.

Further, a solenoid valve (electromagnetic valve) 23 that is duty-controlled is interposed in the fuel supply passage 2'2 communicating with the nozzle opening 20.

Furthermore, in a portion of the fuel supply passage 22 closer to the fuel tank than the part where the solenoid valve 23 is disposed, there is a fuel pressure regulator 24 that operates according to the pressure (negative pressure) in the intake passage B.
is provided, which allows the fuel pressure to be adjusted to an appropriate value.

Note that the reference numeral 26. in FIG. , , 27 indicate a return passage for returning fuel to the fuel tank.

By the way, as shown in FIG. 1.2, each sensor 1, 2 .
A fuel flow rate control means 2B is provided to control the flow rate of fuel supplied from the fuel supply section 9 based on the signals from 4 to 7 in accordance with the operating state of the engine E.

And this fuel flow rate control means 2ENd, each sensor]
, 2.4-6 interfaces 29-34. Interface for solenoid valve 23: S5. 1st to 3rd ROMs 36 to 38 as 1st to 3rd read memories (Read/Write Memory);
It is configured with first to third RAMs 39 to 41 as functions and an 0PU 42 as a processor section.

In addition, each interface 29 to 35 and each ROM 36 to
38 and each RAM39 to 41Vi, 0PU42 and engineering 1
0 bus 43.

The input interfaces 29 to 34 differ depending on the type of sensor, but if the sensor is an analog signal detection type, the input interface 29 to 34 may be a combination of an A/D converter and a serial/parallel converter, etc. If the sensor is of a digital signal detection type, a serial/parallel converter or the like is used as the interface.

In addition, the output interface 35 is used as the output interface 35 to supply a serial pulse train signal to the duty-controlled solenoid valve 23.
A parallel-to-serial converter or the like is used to convert parallel data from the source into a serial signal.

Roughly speaking, the first ROM 36 stores a value corresponding to the fuel flow rate according to the engine speed N and the throttle opening θ as the engine load state [this value is actually the valve opening time T of one duty control as shown in the following table]. , (ms). ] is a read-only memory that stores data in a matrix-type map, and is the base for fuel control after the data TVIri stored in this first ROM 36, so this data T and the base data al f -l
It's called a base map.

The second ROM37 is a read-only memory that stores the correction coefficient value K (dθ/at) according to the acceleration (dθ/at), and the third ROM38 [correction coefficient value according to the engine temperature (cooling water temperature) TV]. K (T
This is a read-only memory that stores V).

The first RAM 39 stores the first 'ROu'i6 so that the fuel flow rate becomes the stoichiometric air-fuel ratio in a preset operating range such as the low-speed, low-load operating range shown by the symbol A in FIG.
Correction coefficient value KA (θ, N
) is a read/write memory that stores data in the form of an IJ hook map.

The correction coefficient value K to be stored in the first RAR II 39 in the second RAM 40ij, in other operating ranges different from the above operating range A, such as the high-speed operating range and the high-output operating range, as shown by reference numeral B4)O in FIG.

(θIN), the fuel flow rate is larger than the stoichiometric air-fuel ratio [lean mixture (lean) state].

Alternatively, the correction coefficient value Kc (θ, N)'i for correcting the signal from the first ROM 36 so that it becomes smaller [rich mixture (rich) state] is stored in the form of a map of IJ Lux. It is writable memory.

Generally, in a multi-cylinder engine E, the explosion timing differs for each cylinder, so the engine speed N constantly fluctuates as shown in Figure 5. Then, a misfire occurs in the cylinder, and as shown in the symbol, large irregularities in the rotational speed N (specifically, a significant decrease in the rotational speed N) occur due to this misfire. When a misfire occurs in this way, the fuel consumption becomes worse as shown by the symbol E in FIG. 6.

Therefore, the mixture should be made lean enough to cause a misfire, but the correction coefficient value KB (θIN)
are stored in the third RAM 41 in the form of a matrix map.

Specifically, this corresponds to the number of times that a misfire occurs within a predetermined period of time (this corresponds to the number of times that the rotational fluctuation ΔN exceeds a predetermined value JN (this value is allowed to have a predetermined width). ] Calculate and determine the correction coefficient value Km (θ, n) that gives a certain value n (this value is also allowed to have a predetermined width), or
The degree of misfire (this is determined by whether or not the rotational fluctuation ΔN exceeds a predetermined value ΔN1) is determined by calculating the correction coefficient value K11 (θ+N) that gives a certain value ΔN. )t″L.

The CPU 42 controls the timing of taking out signals from each sensor 1, 2.
36 to 38 is controlled via the I/O bus 43, data writing and data reading from the first to third RAMs 39 to 41 is controlled via the I/O bus 43, and data to the solenoid valve 23 is controlled via the I/O bus 43. The signal output of the sensor 10 is controlled via the bus 43 and the interface 35', and the signal output from the ROM is controlled based on the signals from each sensor 1, 2.
The main control unit is capable of reading data from the RAMs 39 to 41 and performing appropriate arithmetic processing.

Next, a specific example of control by this fuel flow rate control means 28 will be explained.

First, in response to the signals from the rotation speed sensor 1 and the throttle opening sensor 2, base data T is read from the corresponding address in the first ROM 36, and from this data Tll, 0PU42 determines what operating range the engine E is currently operating in. (Specifically, the operating ranges are marked A, B, G in Figure 4.
! in which region it is located).

And C! The PU 42 stores information in the ROMs 36 to 38 and the RAM so as to maintain an appropriate air-fuel ratio according to the above operating range A-C.
39 reads the data from 41 and outputs it to the solenoid valve 23. Easily calculate each.

Here, in operating region A (low speed, low load operating region), it is desirable to operate at a stoichiometric air-fuel ratio mainly from the viewpoint of exhaust gas purification, and in operating region B (high speed operating region), mainly from the viewpoint of reducing fuel consumption. It is desirable to operate with a lean mixture with an air-fuel ratio of about 18, and in operating region C (high-output operating region), the air-fuel ratio should be about 11 to 13, mainly from the viewpoint of improving output and preventing burnout of spark plugs, etc. It is desirable to operate with a rich mixture of

Therefore, in one example, i-J, the CPU 42 is in the operating range A~
The following output To is calculated according to C.

First, in driving region A.

T, ='T,・KA (θ, N)・K ('rw)・K
(d θ /at)−・・(]N calculation is performed, and in driving region B, TD=T, hot KB
(θIN) Work x('rw)・K (aθ/at)
・Fist ・The calculation (2) is performed, and in driving region C.

TD=T,・KC(θ,N) “ic (Tw)”
The following calculation is performed: K(dθ/at) (3).

In the above equation, Tl1Vi is the data in the first ROM 36.

x (aθ/dt) is the data in the second ROM 37, K
(TV) Data in n-3rd RQM38, K1(
θ, N) is the data name Kc(θ, N) in the first RAM 39.

N) is the data in the second RAM 40, K11 (θ, N)
This is the data in the third RAM 41.

In addition, TI, K(aθ/dt), K(T
w) is fixed data written in advance to RO, M, but KA(θ+'N), K, (θ, N)'l
Kc<θ, N)id This data is written into each RAM after being calculated by the CPU 42 to an appropriate value according to the operating state.

Therefore, 'A (θIN)IKm(θtN)+Kc
(θ, N)ij is rewritten at predetermined time intervals depending on the operating state.

Further, in FIG. 4, the characteristic indicated by the symbol θ is the output characteristic when the throttle opening is θ.

In this way, the appropriate output TD can be determined according to each operating region A-0.
is output, and in addition, in the acceleration operation state (including deceleration operation) and constant speed operation state, Vi, the above equations (1) to (
As can be seen from 3), the output TD should be different, but the case of such an accelerated driving state and a constant speed driving state will be explained.

First, in the case of accelerated driving, the driving conditions change rapidly, so it is necessary to read and process data from memory with extremely high responsiveness. is fixed at a value (for example, 1) and arithmetic processing is performed quickly.

In other words, the fixed data T8 corresponding to the 5th output is stored in the first ROM3.
At the same time, the fixed data K (aθ/at) corresponding to the acceleration is quickly read from the second ROM 37, and the signal is immediately processed and outputted as the output TD. Which operating range A-C is this?
But it's the same.

Also, at this time, temperature data K (
Tw) is also used, but other data KA (θIN),
Kl (θ, N) and Kc (θIN) are fixed at appropriate values as described above.

As a result, even in such an accelerated driving state, fine-grained and responsive fuel control can be performed.

Further, in the case of a constant speed driving state, there is little change in the driving state, or if there is a change, it is gradual, so that writing and reading of data to and from the writable and readable memo IJ-(RAM) is appropriately performed.

In addition, in the case of ideal constant speed operation, there is a possibility that the acceleration becomes zero and the output TD becomes zero.
A correction coefficient value K(dθ/at) within 37 is set.

By the way, the lRO is adjusted so that the fuel flow rate becomes the stoichiometric air-fuel ratio.
Correction coefficient value KA (θ
. A correction coefficient value K for correcting the signal from the first ROM 36 so that the air-fuel ratio becomes another air-fuel ratio.

The calculation of (θ+N) takes more time than the above calculation.

Therefore, for example, in operating region C, 4
~5 rotations, 1st R based on the signal from 02 sensor 4
Correction coefficient value KA (θ, N
) (this value can be obtained instantaneously), the signals 'r and wo from the first ROM 36 are corrected to the stoichiometric air-fuel ratio, and during these 4 to 5 revolutions, the correction coefficient value KA ( θ
The first R
Correction coefficient value K for correcting signal T from OM36
C(θ, N) i0 After calculating the correction coefficient value XC(θ, N) obtained in this way in the PU 42 and writing it to the second RAM 40, the same < 02
Based on the signal from the sensor 4, the correction coefficient value Kc(θ
, N) i using.

The signal Tmk from the first ROM 36 is activated so that the mixture becomes rich.
A correction is made.

Note that the same applies to operating region B.

During a predetermined number of rotations (for example, 20 rotations), several rotations (for example, 4 to 5 rotations) are operated at a stoichiometric air-fuel ratio, and the remaining rotations (for example, 15 to 16 rotations) are operated with a lean mixture.

Also, in the constant speed driving state in driving region B.

In order to improve fuel efficiency, it is preferable to operate with a mixture as lean as possible without causing a misfire.
Depending on the signal from sensor 6.

A correction coefficient value Kl (θ, N) that achieves the optimum lean mixture as described above is calculated as appropriate in the 0PU42,
The correction coefficient value K11 (θ, N) obtained in this way is written to the third RAM 41, and then this third RAM 41
It is read out from and used in the calculation of the output TD.

In this case, when the number of misfires reaches a predetermined value n, t
ri, the correction coefficient value x, (0, N) is updated in the third RAM 41 so as to gradually increase the air-fuel ratio,
The correction coefficient value Kl(θ) is set so that the number of times that misfires will eventually occur becomes a predetermined value n4C.

N) It will be updated in 7.

Roughly speaking, the output TD is corrected σ even according to the engine humidity Tw.
In this case, the correction coefficient value y, (
TW) is 1. For example, if the cooling water temperature is 10℃ or less, K
(TWL) is set as K(TWM) when the temperature is 10 to 50°C and K(TW[l) when the temperature is 50°C or higher, and is stored in the third ROM 38. The correction coefficient value K(TV) is set such that the lower the engine humidity, the richer the mixture becomes.

In this way, the output TD that has been appropriately processed according to the engine operating state is supplied to the solenoid valve 23 via the I10 bus 43 and the interface 35 in a form that has been subjected to pulse width modulation or the like.

Then, the solenoid valve 23 is subjected to duty control according to the output TD and turns on and off the fuel supply passage 22, so that the flow rate of the fuel supplied from the nozzle opening 20 is controlled by the needle valve that moves according to the displacement of the variable venturi 10. 210
The action and phase 1 can be properly controlled.

Note that the reference numeral 44 in FIG. 1 indicates an air cleaner.

Further, the fuel flow rate control means 28' may be configured as shown in FIG. That is, in the one shown in FIG. 7, the first to third ROMs 36 to 38 are the sensors 1, 2, 5, 7
1 to 3 R according to these signals.
Fixed data T,, K(dθ/a t ), y;, (T
w), and the other functions are almost the same as those of the previous embodiment.

Note that in FIG. 7, the same reference numerals as in FIG. 2 indicate substantially the same parts.

Furthermore, the correction coefficient value KA(0,
N) ,,KB(θ,N),K(,(θ,N)tRA
Instead of storing MK, correction coefficient values ya(θ) and xa(θ) are determined according to only 50 or only N.

KC('s t KA(N) , Km(N) , Kc(N1
The correction coefficient value, which may be stored in k RAM and is determined as a constant independent of θ and N, is , K, ,
Kc may be stored in RAM.

FIG. 8 is an overall configuration diagram showing a fuel supply system for an engine as a second embodiment of the present invention. In FIG. 8, the same reference numerals as in FIGS. 1 to 7 indicate substantially the same parts.

In this second embodiment, an intake passage 8 is used as a fuel supply section 9'.
Duty control type electromagnetic fuel injection valve 45 arranged in
is used, and the output TD from the fuel flow rate control means 28
When the fuel injection valve 45 receives this and turns on and off, the fuel flow rate is controlled.

Note that the pressure (negative pressure) in the intake passage 8 is applied to the fuel injection valve 45.
It is connected to a fuel tank 47 via a fuel pressure regulator 46 that operates in response to the fuel injection valve 45, thereby adjusting the fuel pressure injected from the fuel injection valve 45 to an appropriate value.

Further, the fuel injection valve 45 may be disposed upstream or downstream from the throttle valve 25, and the fuel injection valve 45
In addition to providing a simple point injection system in which the branch part of the intake passage 8 is also provided on the upstream side to commonly supply to each cylinder, fuel injection valves 45 are provided in each intake manifold to control the amount of fuel for each cylinder. It is also possible to use a multi-point method.

Also in the case of this second embodiment, a fuel flow rate control means 28' as shown in FIG. 7 can be used.

Furthermore, in each of the embodiments described above, fuel may be supplied continuously or intermittently from the fuel supply section 9.9'.

Note that the ΔN sensor 6 and the acceleration sensor 7 can be provided independently of the sensors 1 and 2, and the QPU 42 can also have the functions of the ΔN sensor 6 and the acceleration sensor 7.

As detailed above, according to the engine fuel supply device of the present invention, by appropriately storing data necessary for control in the read memory or read/write memory,
The calculation time in the processor section can be significantly reduced, which has the effect of realizing fine-grained fuel flow control with extremely fast response.

[Brief explanation of the drawing]

1 to 7 show a fuel supply device for an engine as a first embodiment of the present invention, in which FIG. 1 is an overall configuration diagram thereof, FIG. 2 is a block diagram thereof, and FIG. 3 is a fuel supply unit thereof. Fig. 4 is an output characteristic diagram to explain its action, Fig. 5 is a graph showing an example of engine rotation fluctuation, Fig. 6 is a fuel consumption-air fuel ratio characteristic diagram, and Fig. 7 is an explanatory diagram showing the details of The figure is a block diagram including other control means, and FIG. 8 is an overall configuration diagram showing a fuel supply system for a main engine as a second embodiment of the present invention. 1. Rotation speed sensor, 2. Throttle opening sensor as a load detection section, I. Exhaust passage. 4.02 sensor as oxygen concentration detection section, 5.Temperature sensor, 6.ΔN sensor as rotation fluctuation detection section, 7
...Acceleration sensor, 8..Intake passage, 9,9'...Fuel supply section, 10..Variable venturi, 11e-Differential pressure responsive venturi, 12..Diaphragm, 13.14-.Chamber, 15.. Spring, 16...Movable part, 16a...Space, 17...Check valve, 1B--Orifice, 1
9 - tube passage, 20 - nozzle opening; 2]...Needle valve, 22...Fuel supply passage. 23... Flare/id valve, 24... Fuel pressure regulator, 2
5- Throttle valve, 26.27-Return passage, 2
8, 28'...fuel flow rate control means, 29-35@轡interface, 36-3 days--first to third ROMs as first to third read memories, 39-41...
1st to 3rd RAM as read/write memory, 42-- (!PU as a processor unit. 43... Engineering 10 bus, 44... Air cleaner. 45... Fuel injection valve, 46 ...Fuel pressure regulator, 47
・・Fuel tank, E・・Engine, PM・・Potentiometer. Sub-Agent Patent Attorney Yoshihiko Iinuma Figure 1 Figure 3 Figure 8 Figure 4

Claims (1)

[Scope of claims] and an acceleration detection section that supplies fuel to the intake passage of the engine, and a fuel supply section that supplies fuel to the intake passage of the engine, and the fuel is supplied from the fuel supply section according to the operating state of the engine based on the signals from each of the detection sections. In order to control the fuel flow rate, a fuel flow control means is provided, and the fuel flow control means has a first lead storing a value corresponding to the fuel flow rate according to the engine speed and the engine load state. A second read memory stores a correction coefficient value corresponding to acceleration, and the first read memory stores a correction coefficient value corresponding to acceleration. A first read/write memory that stores correction coefficient values for correcting signals from the above, and a power correction that is stored in the first read/write memory in other operating areas different from the above operating area. a second read memory that stores a correction coefficient value for correcting the signal from the first read memory so that the fuel flow rate becomes a predetermined air-fuel ratio other than the stoichiometric air-fuel ratio based on the coefficient value;
and a write memory, and control for taking out signals from each of the above-mentioned detection sections, control for reading data in the above-mentioned read memory, control for writing or reading data in the above-mentioned read/write memory, and controlling for the above-mentioned fuel supply section. 1. A fuel supply device for an engine, comprising a processor section that performs signal output control and appropriate arithmetic processing. (2) The load detection section is configured as a throttle opening detection section that detects the opening of the throttle valve, and the acceleration detection section differentiates and outputs the signal from the throttle opening detection section. An engine fuel supply device according to claim 1, comprising: (3) The fuel supply device for an engine according to claim 1, wherein the fuel supply section includes a duty control valve. (4) A temperature detection section for detecting engine temperature is provided,
The control means includes a third read memory storing a correction coefficient value corresponding to the engine temperature, and the processor section is configured to control reading of data in the third read memory. A fuel supply system for industrial use according to claim 1. (5) A rotational fluctuation detection section for detecting rotational fluctuations of the engine is provided, and the control means receives a signal from the first read memory so that an optimum lean mixture is obtained in relation to engine rotational fluctuations. A third glue read/write memory is provided for storing a correction coefficient value for correcting, and the processor section is configured to perform data write control or data read control of the third glue read/write memory. A fuel supply device for an engine according to claim 1.