JPS6114442A - Engine fuel supply controller - Google Patents

Abstract

PURPOSE:To achieve proper air-fuel ratio by executing the weighting operation if an external load is coupled when transferring to the decelerating condition. CONSTITUTION:Correction signal producing means (e) will produce correction signals untill deceleration is stopped if an external load is coupled when the engine has transferred to specific decelerating condition. Upon provision of correction signal, output correction means (f) will correct the output from intake condition detecting means (a) to correspond with current condition of intake air on the basis of the intake air condition predetermined time before. Consequently, proper air-fuel ratio of mixture gas can be achieved.

Description

[Detailed description of the invention] (Technical field) The present invention relates to an engine fuel supply control device.

(Prior Art) Generally, in a deceleration state where the engine output request changes rapidly, it is necessary to control the fuel supply amount in accurate response to the change in intake air during the deceleration state.

Conventional fuel supply control devices for this type of engine include:
For example, the one described in Japanese Unexamined Patent Publication No. 56-6032 is known. This device detects the intake air amount with an air flow meter provided upstream of the throttle valve, and controls the fuel supply amount according to the intake air amount per revolution. When the amount of intake air changes in a decreasing direction, the amount of fuel is corrected to increase in accordance with the rate of change, thereby avoiding the air-fuel mixture from becoming lean immediately after deceleration. This will be explained in detail later (see Figure 3), but this is due to the fact that the air flow is reduced immediately after deceleration.
This is because a deviation occurs in the correlation between the output of the engine and the intake air M actually taken into the combustion chamber (hereinafter referred to as effective intake air amount). In this case, one ζ
The effective intake air amount has a larger value.

Therefore, during deceleration, the difference between the two is estimated based on the rate of decrease in the amount of intake air, and the amount of fuel is corrected to increase in accordance with this estimation result.

However, such conventional engine fuel supply #
The p-control device is configured to increase the amount of fuel according to the rate of decrease in the amount of intake air, so if the amount of intake air immediately before deceleration is relatively stable, then deceleration occurs. Is it possible to appropriately correct the air-fuel ratio of the air-fuel mixture? In other cases (for example, when rapid deceleration occurs repeatedly within a short period of time), the air-fuel ratio becomes inappropriate. there were.

That is, if the air-fuel ratio before deceleration is stable, the air-fuel ratio can be appropriately corrected even if the fuel increase is corrected only in accordance with the decreasing speed of the intake air amount. However, if the air-fuel ratio is fluctuating or the degree of reduction is different, even if the rate of decrease in the intake air amount is the same, the intake air amount before the start of deceleration and during deceleration will be different. Therefore, it is difficult to maintain the air-fuel ratio of the air-fuel mixture at an appropriate value during deceleration by simply increasing the amount of fuel in accordance with the decreasing speed.

On the other hand, a deviation in the correlation between the detected value of the intake air amount and the effective intake air amount also occurs during acceleration.
For example, the one described in Japanese Unexamined Patent Publication No. 58-8239 is known. This device calculates the amount of fuel supplied at predetermined time intervals based on the amount of intake air and rotational speed, and when accelerating, it calculates the amount of fuel supplied a predetermined time before (previous) (this is the actual amount supplied, hereinafter referred to as the effective amount). The weighting of the fuel supply amount calculated this time (hereinafter referred to as the calculated supply amount) is calculated by calculating the average (hereinafter, this weighting is referred to as calculation, and the calculation method will be detailed later). By using the average value as the current effective supply amount, the mixture concentration immediately after acceleration (excessive) can be reduced.
Avoiding lean and lean trends.

The reason for this is that there is an inertial force in the air flow meter's meshing plate 1 (the plate 1 that is rotationally driven by the intake air flow and measures its flow rate), and immediately after acceleration, the meshing plate 1 The output of the air flow meter shows a larger value than the effective intake air amount. Therefore, more fuel than necessary is supplied to the combustion chamber, and the air-fuel ratio of the air-fuel mixture becomes 1l, 1k, resulting in the occurrence of a so-called starch spike. Moreover, the cause of leanness is that a deviation occurs again between the two immediately after the above-mentioned overshoot. That is, the overshoot phenomenon attenuates with the passage of time after acceleration, and the output of the air flow system approaches the value of the effective intake air amount. At this time, if all the fuel injected from the injector is sucked into the combustion chamber, the air-fuel ratio will be at an appropriate value, but in reality, some part of the fuel injector is deposited on the wall of the intake pipe and the air is emptied. The fuel ratio becomes phosphorous and a so-called lean spike occurs. Therefore, during acceleration, the above-mentioned weighting is sequentially averaged to correct problems caused by deviations between the two.

However, this device only corrects the fuel supply amount during acceleration to prevent the air-fuel ratio from becoming richer or more concentrated, and it attempts to maintain the air-fuel ratio at an appropriate value during sudden deceleration. It's difficult. Also, is the weight adjustment calculation relatively effective as a method for correcting the deviation between the two series? For example, it is expected that rotational fluctuations may become large (details will be described later), and new problems may occur.

<Purpose of the Invention> Therefore, the present invention provides that, if an external load is connected when transitioning to a predetermined deceleration state, weighting is performed to correct the detected value of the intake state so as to correspond to the effective intake amount. By doing so, even when the state shifts to deceleration due to various operating conditions, the amount of fuel corresponding to the effective intake air amount is supplied to keep the air-fuel ratio of the mixture appropriate, improving engine drivability. The purpose is to make people feel better.

(Structure of the invention) FIG. 1 is an overall configuration diagram for clearly explaining the present invention.

The intake state detection means a detects the state of intake air taken into the engine, and the rotational speed detection means a detects the rotational speed of the engine. Luck Φf: Down! The detection stage C detects the operating state of the engine, and the connection state detection means d detects the state of connection between the engine and the external negative engine. On the other hand, when the engine enters a predetermined deceleration state and an external fiB load is connected, the correction signal generating means C outputs a correction signal until the deceleration is stopped. When the correction signal is not inputted, the output correction means f does not correct the output of the intake state detection means a as corresponding to the state of the intake air, and when the correction signal is inputted, the output correction means f does not correct it for a predetermined period of time.
Based on the state of the intake air of J, the output of the intake state detection means a is corrected so as to correspond to the current state of the intake air, and the correction is executed sequentially at each predetermined timing. The means 10 (g) outputs the output of the positive means (f) at predetermined timings as corresponding to the state of the intake air, and the supply amount calculation means (10) and the output correction means (13) correspond to the state of the intake air. Based on the output of the rotation speed detection means (e):
Calculate the rn supply amount. Then, by supplying fuel to the engine based on the U' force of the fuel supply means 1 or the supply amount calculation means, the detected value of the intake state immediately after deceleration is appropriately corrected, and the amount always corresponds to the effective intake air amount. ].

(Example) Hereinafter, the present invention will be explained based on the drawings.

2 to 6 are diagrams showing a first embodiment of the present invention.

First, the configuration will be explained. In Fig. 2, it is a 1.81 engine, and intake air is supplied to each cylinder from an air cleaner 2 through an intake pipe 3, and fuel is injected by an injector (fuel supply means) 4 based on an injection system 81. Ru. The intake air flow rate QaG is detected by an air flow meter (intake state detection means) 5 and controlled by a throttle valve 6 in the intake pipe 3. Further, the opening degree Cv of the throttle valve 6 is detected by a throttle valve 1 opening degree sensor (operating state detection means) 7, and the rotation speed N of the engine 1 is detected by a crank angle sensor 8. Roughly speaking, the connection state between the engine 1 and the external load is detected by the connection state detection means 9, and the connection state detection means 9 is constituted by a neural system IO and a cranotis system 1]. Neural l-ral suinochi] 0 detects that the hand/IiJ+change j4 transformation 41 shaku is at the 2r--1-ral position and sends the neural 1-ral signal SI
The Kusonochisu Inochi 11 detects the engagement/disengagement state of the clutch and outputs the clutch signal SC. Signals from air valve 1, throttle valve opening sensor 7, crank angle sensor) 3, neutral switch, switch 10, and crank angle switch 11 are input to the control unit 12, and are sent to the control unit 12. .

Eye 2 has the functions of correction signal generation means, output correction means/means, means ↑, 9, and supply amount calculation means.

Control 1 call unit 71-12 CPU13, ROM1
4, RAM 15 and I10 boat 16. The CPU 13 reads necessary external data from the I10 boat 16 according to the program written in the ROM +4, performs arithmetic processing while exchanging data with the RAM 15, and processes the processed data as necessary. Output to I10 port 16. I10
Signals from the sensors 5, 7, 8, and 9 are input to the port 16, and an injection signal Si is output from the I10 baud 1-16. The ROM 14 stores calculation programs for the CPU 13, and the RAM 15 stores data used in calculations in the form of a map or the like.

Next, the action will be explained.

- In general, EGI type engines inject fuel in an amount corresponding to the engine load in synchronization with rotation, so the state of intake air per revolution (engine load state) is need to be detected. Therefore, a sensor is provided to detect the amount of intake air. In fact, although the output of the sensor accurately correlates with the actual intake state during steady operation, a deviation in the correlation occurs during rapid deceleration operation.

This is because the measuring plate 1 of the sensor is forcibly displaced under the influence of the inertia of the intake air. That is, when the throttle valve becomes fully closed at timing t as shown in FIG. 3 (Fl), the pressure inside the intake pipe on the downstream side of the throttle valve gradually approaches the effective intake air amount as shown in +bl in the same figure. decreases to At this time, the air flow rate that had passed through the Senna's nojuring plate until immediately after the throttle valve was fully closed suddenly changes, so a flow rate that is much smaller than the original air flow rate when the throttle valve is fully closed is detected. As shown by the solid line in Figure 3, the sensor output suddenly decreases at timing t□, and then gradually returns to the effective intake air amount (Figure 3).
~ Medium dashed line (Y) or equivalent). As a result, an error occurs between the output of the sensor and the effective intake air amount as shown in the shaded area in Figure 3 (C1), and the two do not correlate accurately.In addition, such an error varies depending on the degree of deceleration. Conventionally, the amount of fuel supplied was increased depending on the rate of decrease in the sensor output.However,
If only the decreasing speed is used, it is difficult to uniformly determine the influence of the inertia of the intake air (which is also related to the flow rate at that time), and the fuel supply amount is not necessarily corrected appropriately.

Therefore, in this embodiment, we focused on the merits of calculation for market identification, and
By applying this during deceleration, the output of the sensor is brought close to the actual intake air amount very accurately. In the figure, P,
~P. indicates each step of flowchart 1. This program is executed once every rotation of the engine.

Read the intake air ffi Q a and the rotational speed N using J-zu and Pl, and then the operating condition consisting of P2 to P'4! '34
'I-specific f+:r-U The operating state of the engine 1 is determined by HF. In steps 2 to 1)-4, the following conditions are determined.

P. Is the second throttle valve 6 fully closed? That is, it is determined whether or not the engine has transitioned to a deceleration state.

1): Is gear in the neutral position?

P4: Is Kuranochi connected?

Then, it is determined from these determination results whether the operating state of the engine 1 corresponds to the following states A or B, and the process proceeds to different steps depending on the state.

Δ state: When the throttle valve 6 is not fully closed at P2, when the gear is in the neutral position at P, when the clutch and chi are disconnected at P%. Such a state corresponds to when the engine 1 is in a deceleration state but no external load is connected. If it is determined that the state is A, the process proceeds to P.

In state B, when the following conditions are met: l), the throttle valve 6 is fully closed, r) the gear is in a position other than 1-neutral in 3, and the clutch is connected in P4. This state occurs when the external ``a'' load is connected during deceleration, and in this case, proceed to ①]6.

Now, in state A, the output Qa of air flow meter 5
It is determined that ρ is almost close to the effective intake air amount, and P is used to correct the current intake air amount Qe.
Replace with Here, the positive intake air amount Qe is a correction value when the output Qa of the air flow meter 5 is corrected to approximate the effective intake air amount, and in state A, it is Qa - effective intake air amount. Let it be Qa-Qe.

On the other hand, in state B, the output Qa of the air flow meter 5
It is determined that the intake air amount is not close to the effective intake air amount, and the flow shifts to correction flow EF consisting of P6 and P7, and the output Qa is corrected.

In correction flows F and F, first read out the intake air ke (yu α-1 (corresponding to the previous effective intake amount)) from the previous time (corresponding to the previous routine), and then use the following formula in 7. Accordingly, the current positive intake air amount Qe is calculated.

Qc-Q, -1・n, /rl'll-(04-t)・
(m - n,) / m In the 00 formula, a predetermined weighting coefficient (
By multiplying n/rn and (m-n)/rn or equivalent) and finding the sum, the current output Qa of the air flow meter 5 is corrected to correspond to the effective intake air amount. . Here, rn and n are set to optimal values by, for example, experiments. As an example, rn-3, b-3
The case where this is set will be described in detail later with reference to FIG.

1 step ■), or after calculating the corrected intake air amount Qe in P7, set the current corrected intake air amount Q6 as the old corrected intake air amount (-1 to Q) in P8, and proceed to P9, (■). Then, calculate the fuel supply amount 1゛e according to formula 1.

1'e=K·Qe/N■ I11, K: constant, ■)l(l outputs an injection signal Si that measures the pulse width corresponding to the fuel supply amount Te.

Figure 5 is a timing chart when transitioning from the △ state to the B state.

In Fig. 5, Q a = Q, during operation,
When the transition from state A to state B takes place at immi- nozzle t2, the output Qa of flowmeter 5 changes as shown by curve C, and a deviation occurs between the effective intake amount and the curved line. Therefore,
In order to correct this deviation, a weighted calculation based on the above-mentioned formula 0 is executed every engine revolution. In formula 0, m
・When setting -8, n=3, the weighting for each rotation after timing 2 is calculated sequentially as follows, and the corrected intake air amount Qe (however, Qe=Q, ,
Q72. Q, --) is determined.

Q, -(3/8)Qa-1-(5/8)Q.

12 − (3/8)Q, ,+1+−(5/8)Q
.

-(3/8)Qα+lto (5/8) ・((3/
8)Qa + (5/8)Qa-41Q3=(3/
8) Qai2. L (5/8) Q2- (
3/8)Qαsu1−(5/8)・((3/8)toQ+(+(5,z'8)Q+1(same below) In other words, in this calculation, after timing While reducing the weight, the timing t, :sE, the airflow l: 1 no 5 Q;
l is corrected. (, As shown by curve I8 in the figure, the corrected intake air amount Qe (Qc=Q, , Q2, Q3--
1 can be accurately approximated to the value of the effective intake air amount shown by curve I]. In addition, this calculation is based on the intake air amount Qo before the start of deceleration, and the corrected intake air amount Qe approximates the effective intake air amount no matter what operating conditions the deceleration occurs.
can be obtained. As a result, the air-fuel ratio of the air-fuel mixture in the deceleration state can always be kept appropriate, and drivability can be improved. Then, at timing t3, when the deceleration state shifts to a steady state (for example, idle state), Qa=Qe as before timing 2, and the output Qa of the air flow meter 5 becomes close to the effective intake air amount again.

In this embodiment, an example was shown in which m-8, n, = 3 were set, but FIG. 6 shows changes in the corrected intake air iQe when these values are changed. In Figure 6, curve G is large when n/m is large, curve 1 (is 07 m or appropriate), curve ■ is n
/ represents the case where m is small.

Further, although this embodiment shows an example of deceleration from a steady state to an idle state, the application of the present invention is not limited to deceleration to an idle state.

For example, the present invention can be applied to all cases where deceleration occurs from a steady state to near an idling state, or where a deviation occurs in the correlation between the output of the airflow make 5 and the effective intake air amount due to deceleration.

Roughly speaking, in this embodiment, the weighting calculation is performed on the intake air amount, but the invention is not limited to this, and the same effect can be obtained even if the weighting calculation is performed on the fuel supply amount, for example.

7 to 10 are diagrams showing a second embodiment of the present invention. In this embodiment, when there is no load, the weighting is limited to a predetermined time period, and rotation is performed while correcting deviation from the effective intake air amount. It suppresses fluctuations.

First, the background of this embodiment will be described.

In general, when the throttle valve opening is constant and the rotational speed N changes, the pressure in the intake pipe (hereinafter referred to as , called inspiratory pressure) l)
fluctuates, causing a phase shift between the two. This is because the intake pipe has a predetermined volume; for example, if the volume is zero, no phase shift will occur. On the other hand, such a deviation is said to suppress engine speed fluctuations during no-load operation.
It leads to negative effects. For example, in FIG. 7, if the rotational speed N when there is no rotational variation is N=No and the intake pressure P is P=Po, then at timing t'4, the intake pressure P is higher than when there is no rotational variation ( P>Po
), at timing t, the intake pressure P is low (p<P
O). Therefore, when fuel calculated according to No and po is injected, the air-fuel ratio of the air-fuel mixture shifts to the lean side at timing t'4, and shifts to the lean side at timing t.

Here, if the air-fuel ratio of the air-fuel mixture corresponding to N01PO is at point X in FIG. , the torque is thereafter reduced in accordance with the variation range ΔA/F, and the increase in rotation is suppressed. On the other hand, at timing t'4 when the rotation decreases, the air-fuel ratio shifts from point X to the Lynch side, so the torque increases and the rotation increases.

In other words, even if the rotational speed N changes due to a cause such as a deviation in the correlation between the air flow meter output and the effective intake air amount, the torque is appropriately controlled due to the above-mentioned phase deviation, and rotational fluctuations are prevented. is suppressed.

However, when the weighting calculation is performed in accordance with the deviation in the correlation, torque fluctuations based on air-fuel ratio fluctuations are also reduced.

Therefore, even if the rotational speed N changes, the torque is not properly controlled, and rotational fluctuations cannot be suppressed. As a result, when the weighting is executed during no-load operation, the 9th
When no calculation is performed as shown by curve J in the figure (curve K
(which corresponds to this), a large undulation occurs in the rotational speed N, causing a problem that rotational fluctuation becomes large.

On the other hand, if the weighting calculation is stopped in order to avoid such rotation fluctuations, the degree of deviation between the output of the air flow meter and the actual J intake amount will be reduced in cases such as immediately after dry cooking in an idling state. becomes large, resulting in engine stall or extreme rotational speed N
A decrease in the temperature will occur.

Therefore, in the present embodiment, when the throttle valve 6 shifts from a predetermined opening degree to a fully closed state under no load, the weight I/'ge6jJ calculation is executed within a predetermined time, and thereafter the mmii'ge/ii calculation is performed. By stopping the engine, the deviation from the actual intake air amount J is corrected, and rotational fluctuations are suppressed while preventing an extreme drop in the rotational speed N.

FIG. 10 is a flowchart of a program that implements the above-mentioned functions. In this figure, steps that perform the same processing as in the first embodiment are given the same number and their explanations are omitted, and steps that perform the same processing as in the first embodiment are omitted. will be assigned a number in the 20s and its processing content will be explained.

In FIG. 10, in the driving state determination flow U Hhr, the determination contents in steps P to P'4 are the same as in the first embodiment, but the determination of the driving state is partially different, and in addition to state B, the following A ', determine the C state.

A' condition: P, when throttle valve 6 is not fully closed. This state corresponds to when the engine 1 is not in a deceleration state. Then, in this case, proceed to P5.

C state: When the throttle valve 6 is fully closed at Pz and in the gear or neutral position at P3, or when the throttle valve 6 is fully closed at P2 and at P3, the throttle valve 6 is fully closed. When it is in a position other than Ral but is separated from Crafti in P4. This state is when no external load is connected during deceleration, and in this case the process proceeds to PILO.

Then, in the case of C combustion, the elapsed time T after the throttle valve 6 becomes fully closed at P, 0 (after shifting to the deceleration state) is compared with a predetermined time TO.

When 1゛≦-po, shift to correction flow EF, and T〉
If TO, proceed to P. Therefore, in the C state, the weighting calculation is performed within the predetermined time 'r, the output of the air flow make 5 is corrected, and the air-fuel ratio of the air-fuel mixture is maintained at an appropriate value. As a result, it is possible to prevent the engine from stalling or from drastically decreasing the number of revolutions, even if the engine is running immediately after dry cooking in an idle state. Further, after the predetermined time period has elapsed, the weighting calculation is stopped. Therefore, according to the above-described principle, the torque in the idle state is appropriately controlled and rotational fluctuations are suppressed.

As a result, drivability can be improved.

(Of course) According to the present invention, the output of the intake state detection means is appropriately controlled.
The effective intake air amount can be varied by correcting the engine speed, and the air-fuel ratio of the air-fuel mixture during deceleration can always be kept at an appropriate level, thereby improving engine drivability.

In addition, in the second embodiment, it is possible to correct the difference between the effective intake amount during deceleration and the air-fuel ratio during deceleration in the no-load state, and suppress rotational fluctuations while maintaining the air-fuel ratio of the air-fuel mixture at an appropriate value. .

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of the present invention, 2nd to 6th circles are diagrams showing the first embodiment of the present invention, FIG. 2 is a schematic configuration diagram thereof, and FIGS. 3 (8) to (C) are Fig. 4 is a flowchart showing the program for controlling the amount of fuel supply, Fig. 5 is a diagram showing the state of change in the amount of intake air, and Fig. 6 is a diagram showing the weighting. 7 to 10 are diagrams showing the state of change in the corrected intake air amount when the calculation weighting coefficient is changed, and FIGS.
Figures (8) and (b) are timing charts showing the changes in rotation speed and intake pressure, Figure 8 is a diagram showing the relationship between luke and air-fuel ratio, and Figure 9 is a diagram showing the changes in rotation speed. FIG. 10 is a flowchart 1- showing a program for controlling the fuel supply amount. Reference Signs List 1 - engine, 4 fuel supply means, 5 intake state detection means, 7 - operating state detection means, ) 3 rotation speed detection means, 9 connection state detection means, 12 controller I/roll unit y l-(?1if signal generation means, storage means, supply M calculation means).

Claims (2)

[Claims] (1) a) intake condition detection means for detecting the condition of intake air taken into the engine; b) rotation speed detection means for detecting the engine rotation speed; and c) operating condition detection means for detecting the engine operation condition. d) connection state detection means for detecting a connection state between the engine and an external load; and e) if the external load is connected when the engine transitions to a predetermined deceleration state, a correction signal is sent until deceleration is stopped. f) When the correction signal is not input, the output of the intake state detection means is not corrected as corresponding to the state of the intake air, and when the correction signal is input, the output of the intake state detection means is not corrected, and when the correction signal is input, the output of the intake state detection means is g) Output correction means for correcting the output of the intake state detection means based on the state of the intake air so as to correspond to the current state of the intake air, and sequentially executing the correction at predetermined timing; g) output correction means; h) supply amount calculation means for calculating the fuel supply amount based on the outputs of the output correction means and the rotation speed detection means; An engine fuel supply control device comprising: i) fuel supply means for supplying fuel to the engine based on the output of the supply amount calculation means. (2) If the external load is connected when the engine shifts to the idle state, the correction signal generating means outputs the correction signal until deceleration is stopped, and if the external load is not connected, a predetermined period of time has elapsed. 2. The fuel supply control device for an engine according to claim 1, wherein the correction signal is output until the fuel supply control device outputs the correction signal.