JPH01208533A - Fuel controller for engine - Google Patents

Abstract

PURPOSE:To eliminate an expensive atmospheric pressure sensor by memorizing the output of an intake air pressure sensor, as detected value of atmospheric pressure, under a predetermined state of the small change of intake air pressure at the time of starting an engine and judging whether it is in an enrichment mode or not, based on the detected value. CONSTITUTION:During the operation of an engine 1, for a predetermined period in a term from the time of switching on an electric source to the time of switching on a cranking switch 13 for operating a starter, the changing component of intake air pressure at the downstream of a throttle valve 5 detected by a pressure sensor A is detected whether less than a predetermined value or not, in a controller 14. Next, according to the detected result, a pressure signal from the pressure sensor 6 is memorized by a memorizing means as detected atmospheric pressure value. At the time of an operation mode which is not a starting mode, an enrichment mode is judged in case that the pressure signal of the pressure sensor 6 increases more than value which is smaller than the memorized detected atmospheric pressure value by predetermined value and then an injector 4 is controlled to increase fuel supply quantity.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention is applicable to the fuel side of an engine, which detects atmospheric pressure without using an atmospheric pressure sensor and determines the amount of fuel injection to be supplied to the engine. This relates to al equipment.

[Prior Art] A conventional engine fuel control device uses a pressure sensor that detects the intake manifold pressure P in the intake passage downstream from the throttle valve, which is linked to the accelerator pedal and limits the amount of air taken into the engine, as an absolute pressure. A separate atmospheric pressure sensor is provided, and based on the atmospheric pressure detected by this atmospheric pressure sensor, it is determined whether or not the engine is in enrich mode, which is a type of engine operation mode, and the supply is supplied to the engine according to the result of this determination. The fuel injection amount was determined by the pulse duration.

(Problems to be Solved by the Invention) Since the conventional fuel control device for an engine is configured as described above, there have been problems such as the device itself becoming expensive due to the use of an expensive atmospheric pressure sensor.

This invention was made to solve the above-mentioned problems, and an object of the present invention is to obtain an engine fuel control device that can determine the fuel injection amount according to atmospheric pressure without using an atmospheric pressure sensor. .

[Means to solve the problem]

The engine fuel control device according to the present invention includes a pressure sensor for detecting intake manifold pressure, a cranking detection means, and a pressure change amount for a predetermined period from when the power is turned on until the cranking detection means detects the intake manifold pressure. pressure change detection means for detecting that the pressure is below a predetermined value; storage means for storing the pressure signal of the pressure sensor as an atmospheric pressure detection value at the time of this detection; Enrichment control means is provided for determining the enrichment mode and increasing the fuel supply amount when the pressure signal increases above the value.

[Function] The engine fuel control device according to the present invention uses an intake manifold pressure equal to the atmospheric pressure before engine rotation as the detected atmospheric pressure value used to determine the enriched mode for increasing the amount of fuel supplied during the enriched mode. Since it is read from the pressure sensor, the fuel supply amount can be determined accurately.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure shows one embodiment of the present invention, and in the figure, 1 is a well-known engine mounted on, for example, a vehicle, 2 is an intake manifold of the engine 1, and 2A is connected to an upstream port of the intake manifold 2 and is connected to the intake manifold 2. An intake pipe main body forming the intake pipe, 3 an air cleaner installed at the entrance of the intake pipe main body 2A, and 4 an injector that injects and supplies fuel into the intake pipe main body 2A. 5 is the intake pipe body 2A
The throttle valve 5A is connected to the throttle valve 5 and has an analog voltage corresponding to the opening degree of the throttle valve 5. For example, the throttle opening sensor 6 of potentiometer 2 is installed in the intake pipe main body 2A on the downstream side from the throttle valve 5, and detects the intake manifold pressure P as an absolute pressure, and generates a pressure corresponding to the detected pressure. It is a pressure sensor that outputs a signal. Further, 7 is a cooling water temperature sensor that detects the cooling water temperature WT of the engine 1, 8 is an exhaust manifold of the engine 1, 9 is an air-fuel ratio sensor that detects the oxygen concentration of the exhaust gas in the exhaust manifold 8, and 10 is a sensor that purifies the exhaust gas. It is a three-way catalytic converter. 11 is an ignition coil that supplies high voltage to the spark plug (not shown) of the engine 10; 12 is an igniter for energizing the ignition coil 11 when turned on; 13;
is turned on and off to turn on and off the operation of the starter (not shown) that drives the engine 1 for starting.
6 1 is a cranking switch that outputs an off signal.
4 inputs various parameters and battery voltage obtained by detecting each state of the engine 1, performs various judgments and calculations based on these parameters and preset data, and displays the atmospheric pressure. This is a control device that calculates the fuel injection amount etc. by reading the detected atmospheric pressure value and performs control accordingly.

Next, the internal configuration of the control device 14 will be described in detail with reference to FIGS. 2 and 3. In Figure 2, 10
0 is a microcomputer, and CPU200.0 executes the flow shown in FIG. A counter 201 that functions as a timer, and a timer 202 that measures the rotation period of the engine 1.
, an A/D converter 203 that converts analog (No. 3) into digital signals, an input port 2o4 that inputs and transmits digital signals, a nonvolatile RA that functions as a work memory, etc.
M205, R that stores the flow shown in Figure 3 as a program and also stores data for comparison judgment and calculation.
It is comprised of an OM 206, an output port 207 for outputting the calculated fuel injection amount, etc., a common bus 208 that commonly connects each of the above components, and the like. Reference numeral 101 denotes a first human-powered interface connected to the connection between the primary coil end of the ignition coil 11 and the collector of the transistor of the igniter 12, and for inputting an ignition signal to the microcomputer 100 for detecting, for example, the engine speed NE. The face circuit 102 is a throttle opening sensor 5A.

Pressure sensor6. A second human power interface circuit for sequentially introducing analog output signals from the battery 16 via the cooling water temperature sensor 7, the air-fuel ratio sensor 9, and the key switch 15 (described later) to the A/D converter 203; 103 is a cranking switch; This is a third human-powered ink face circuit for inputting 13 on/off signals and other signals. 104
105 is an output ink face circuit connected between the output boat 207 and the injector 4, etc., and 105 is an output ink face circuit connected via a key switch 15 to the ■ side of the battery 16 whose θ side is grounded, and which supplies power to the microcomputer 100. 1
A power supply circuit 106 is a second power supply circuit that is always connected to the ■ side of the battery 16 and supplies power to the RAM 205.

Next, the operations executed by the CPU 200 in the microcomputer 100 will be explained.

First, when the key switch 15 is turned on, the battery 16
A voltage is applied to the first power supply circuit 105. The first power supply circuit 105 applies a constant voltage to the microcomputer 100, and the control device 14 starts operating. First, at the start of operation, initialization is performed, for example, the timer is set to 0, that is, the counter 201 is reset to 0. Upon the start of this operation, an interrupt is generated at predetermined time intervals, and the flow of the interrupt routine shown in FIG. 3 is repeatedly executed.

First, in step 301, the engine rotation speed N is calculated based on the measurement data of the timer 202 that measures the rotation period of the engine 1, and is stored in the RAM 205. The timer 202 inputs the ignition signal generated when the igniter 12 changes from on to off from the igniter 12 via the first input interface circuit 101, thereby controlling m from the (m-1) ignition time. Measure the time until ignition occurs. This measurement data is stored in RAM20 in a separate routine.
5. Next, in step 302, a pressure signal representing the intake manifold pressure P is sent from the pressure sensor 6, and a throttle opening signal representing the throttle opening θ is sent from the throttle opening sensor 5A to the second human power interface circuit 102 and the A/D converter. Step 303 to sequentially read the 0th order via 203 and store it in the RAM 205.
In the same way as Stembu 302, Ba Nteri]
Step 304: Convert the voltage of 6 into a digital value, read the panteri voltage, and store it in the RAM 205.
, the engine rotation speed N read from the RAM 205
, and the intake manifold pressure P, respectively, calculate the volumetric efficiency Ctv of the engine 1 experimentally determined in advance as a function of the engine speed and the intake manifold pressure, and store it in the RAM 205.8 Next, step 305 , the basic pulse width TPW is the basic time of fuel injection. is calculated using the formula K (coefficient) x P (intake manifold pressure) x CEV (volume efficiency), and the result is stored in the RAM 205. However, in the above equation, the values of the coefficients are not read from the ROM 206. Next, in step 306, whether or not the air-fuel ratio sensor 9 is in an active state, that is, the air-fuel ratio sensor 9 is checked.
It is determined whether the air-fuel ratio feedbank condition is satisfied based on whether the output signal of changes within a predetermined time (or the level of the cooling water temperature WT detected by the cooling water temperature sensor 7, etc.). In step 306, if the feedback condition is satisfied, in step 307, a feedback correction term CF11 for the fuel injection time is calculated by proportional-integral control according to the output of the air-fuel ratio sensor 9, and is stored in the RAM 205. On the other hand, if the feedback condition is not satisfied in step 306, the process proceeds to step 308 and the correction term CF11
Set to 1 in RAM2O3.

After processing step 307 or 308, proceed to the next step 30.
Proceed to step 9. In step 309, it is determined whether the ignition signal from the igniter 12 has been input even once.

The process proceeds to step 310 in which the ignition signal must have been input at least once.

In step 310, since the signal from the cranking switch 13 is input through the third human-powered ink face circuit 103, it is determined whether the cranking switch 13 is off. If the cranking switch 13 is off, the process proceeds to step 311, where the battery voltage V is continuously outputted from the RAM 205, and it is determined whether or not this battery voltage V is greater than or equal to flV. If the battery voltage V is 8V or more, the process proceeds to step 312, where the counter 201 is counted up and the elapsed time of the timer is increased. Step 31e
Next, proceed to step 313, in which step
It is determined whether the elapsed time of the timer has reached 0.1 seconds, that is, whether the count value of the counter 201 has reached a predetermined value. If 0.1 second has not elapsed, the process advances to step 314, where the pressure signal representing the intake manifold pressure P is read out from the RAM 205, and the maximum value P N@X and minimum value P are read out from the RAM 205.
IIIN is detected and stored in the RAM 205.

In step 313 above, the elapsed time of the timer is 0.
If it is determined that it is 1 second, the process advances to step 315;
In this step, the maximum value P□ of the intake manifold pressure P is stored in the RAM 205.

and its minimum (a pressure signal representing IPMIN) to determine whether the pressure change ΔP (-P, , -P□M) exceeds a predetermined pressure of, for example, 20 mmHg. If ΔP is 20 μHg or less, the process proceeds to step 316, and in this step, the pressure signal representing the intake manifold pressure P is read from the pressure sensor 6 and is set as the atmospheric pressure detection value RA representing the atmospheric pressure PA.
Store in M205.

Also, in step 310, it is determined that the cranking switch 13 is on, or in step 3,
If it is determined in Step 11 that the battery voltage 7 is less than 8V, the process proceeds to Step 317 and the counter 201 is reset to 0.

If it is determined in step 309 that the ignition signal has been input even once, after the process in step 317, if it is determined in step 315 that the pressure change ΔP exceeds 20 Hg, and after the process in step 316, In either case, proceed to step 318;
In step 31B, it is determined whether the engine 1 is in the starting mode. The engine rotation speed N section of the rotation speed signal successively received from the RAM 205 is the engine rotation speed N1 shown in FIG.
If it is below, it is determined that the starting mode is present, and if it exceeds, it is determined that the starting mode is not present. In step 318, if it is determined that the mode is not the start mode, the process proceeds to step 319, and the RA
The atmospheric pressure detection value representing the atmospheric pressure P is read from M205, the set value corresponding to the predetermined pressure ΔPt is read from the ROM 206, and the lower limit pressure P of the enrich mode shown in FIG. 4 is read out.
* is calculated according to the calculation formula of P, -Pl-ΔP1, and an enrich mode pressure dark value corresponding to the lower limit pressure P* of the enrich mode is calculated. After step 319, in step 320, it is determined whether the intake manifold pressure P of the pressure signal read from the RAM 205 is equal to or higher than the lower limit pressure 20 of the enrich mode, that is, whether or not the enrich mode is set. If the enrich mode is determined in step 320, in step 321, the basic pulse width TFMO read from the RAM 205, the feedback correction term Cra (however, 1 in the enrich mode), and the enrich mode in the enrich mode read from the ROM2 Q6. The pulse width T of fuel injection is calculated by multiplying the coefficient C1 by the total.

On the other hand, if it is determined in step 31B that the mode is the starting mode, or if it is determined in step 320 that the operating mode is not the enrich mode but that allows air-fuel ratio feedback control, the process proceeds to step 322, where the basic pulse width TPW is stored from the RAM 205. and the feedback correction term crs are read out and multiplied to calculate the fuel injection pulse width TPw.

After the processing in step 321 or 322, the process advances to the next step.

Although the engine speed is used to determine the starting mode, the level of the cooling water temperature may also be determined.

In Figures 5 and 6, the horizontal axis represents time, and the vertical axis represents (a).
(b) shows the on/off signal from the key switch 15, (C) shows the on/off signal of the cranking switch 13, and (d> shows the ignition signal from the igniter 12).

FIG. 5 shows a case where a pressure signal representing the atmospheric pressure PA is read from the pressure sensor 6 without any malfunction. That is, the key switch 15 is turned on at time t0, and 0.1 seconds have elapsed from time L0 at time 1. Until then, cranking switch 1
3 is off and no ignition signal is input from the igniter 12 even once. Therefore, the amount of change in the intake manifold pressure P during this period is small and is less than 20 mmHg, so the time t + (7) P (t +) point Detect atmospheric pressure P^ at . At this time, the engine 1 is not yet rotating, is not taking in air, and there is no pressure loss, so the pressure detection error is extremely small at time 1 after time 0 t1. The cranking switch 13 changes from off to on, and at this time the engine 1 starts operating. After time 11, the engine 1 rotates and repeatedly sucks air from the air cleaner 3 through the two intake pipes and the intake manifold 2, and at time t.
At a time after 2.

When the ignition signal is generated at t4 + tS..., the intake manifold pressure P is input to perform the explosion process and repeat the well-known process of the engine 1.
fluctuations become more intense. Therefore, as after time t2, the pressure fluctuation may exceed 20 ma+Hg, or at some point.

As described below, if the ignition signal is input even once, the detection error will increase, so the pressure signal from the pressure sensor 6 is not used as the atmospheric detection value, and from time t0 to t1, it is set to 0.
Since the time is over 1 second, the pressure signal is also not used as the detected atmospheric pressure value.

FIG. 6 shows a case where the signal from the key switch 15 is temporarily turned off and turned on again due to some reason, such as a momentary power cut. While the engine 1 is rotating, the signal from the key switch 15 is received at the moment [.

Even if it is turned off at time t, and then turned on again at time t, the intake manifold pressure P is much higher than the atmospheric pressure shown by the dashed-dotted line because the intake is continuously repeated due to engine 1 running and turning on. The pressure becomes negative and there is a large ripple fluctuation. In this case, the cranking switch 13 is certainly turned off at the time t, and it is also turned off at the time t when 0.1 seconds have elapsed since then, and at that point, the ignition is also turned off. No signal is input, but the variation in intake manifold pressure P is 20II
Since it exceeds IIIHg, P at time t8 (tw)
The intake manifold pressure P at the point is detected and is not directly read as the detected atmospheric pressure value.

In the above embodiment, the pressure change ΔP, which is the difference between the maximum value P MAX and the minimum value P HIM of the intake manifold pressure P, was compared with a predetermined pressure. It may be compared with a predetermined pressure.

Also, in step 316, the intake manifold pressure P is not newly read from the pressure sensor 6 and the intake manifold pressure P is not read.
The intake manifold pressure read into 302 is stored in RAM.
205 may be read out and used as the detected atmospheric pressure value.

〔Effect of the invention〕

As described above, according to the present invention, if the intake manifold pressure fluctuation is less than a predetermined value for a predetermined period from when the engine is turned on until the cranking switch is turned on, the pressure sensor detects the intake manifold pressure. The signal is stored as an atmospheric pressure detection value, and when the output of the pressure sensor increases beyond a value smaller than the atmospheric pressure detection value by a predetermined value, it is determined to be enrich mode and the fuel supply amount is increased, resulting in an inexpensive configuration. There are effects that can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the entire device according to an embodiment of the present invention;
Fig. 2 is a block diagram showing the configuration of the control device etc. in the above device, Fig. 3 is a flow diagram showing the operation flow of CPtJ in the control u device, Fig. 4 is an explanatory diagram showing the operation mode, and Fig. 5 is an explanatory diagram showing the operation mode. 6 and 6 are timing diagrams of the states of each part of the device. In the figure, 1...engine, 2...intake manifold, 2A...intake pipe body, 4...injector,
5... Throttle valve, 6... Pressure sensor, 9...
Air-fuel ratio sensor, 11... Ignition coil, 12... Igniter, 13... Cranking switch, 14...
Control device, 15... Key switch, 16... Battery, lOO... Microcomputer, 101-10
3... 1st to 3rd person Kainta face circuit, 104.
...Output interface circuit, 105, 106...1st. Second power supply circuit. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent Masu Oiwa 1st cause 6, ε force sensor 2nd figure 113 Cranking switch 3rd factor (b) ≦ 8 9 %J QNl
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He He C) -Q u ”C
s″＋＋＋＋＋− Procedural amendment (voluntary) 2. Name of the invention Engine fuel control device 3. Relationship with the person making the amendment Patent applicant address 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name (601) ) Mitsubishi Electric Corporation Representative Moriya Shiki 4, Agent Address 2-3-5 Marunojiju-chome, Chiyoda-ku, Tokyo
, Target of amendment 6, Contents of amendment (1) In the 4th line of page 18 of the specification tube, ``Dusutata'' is amended to ``Didsuta''. that's all

Claims (1)

[Claims] A pressure sensor that detects the intake manifold pressure in the intake passage on the downstream side from the throttle valve that limits the amount of intake air to the engine as an absolute pressure, and a cranking sensor that detects when the starter that drives the engine for starting is turned on. a detection means; and a pressure change detection means for detecting that a change in pressure detected by the pressure sensor is less than or equal to a predetermined value during a predetermined period from when the power is turned on to when the cranking detection means detects the cranking. , storage means for receiving the detection signal of the pressure change detection means and storing the pressure signal from the pressure sensor as an atmospheric pressure detection value, and a storage means that is smaller than the atmospheric pressure detection value by a predetermined value when the engine is in an operating mode other than a starting mode. An engine fuel control device comprising enrichment control means for determining an enrichment mode and increasing the fuel supply amount when the pressure signal of the pressure sensor increases from the value.