JPH0237150A - Fuel supplying apparatus for engine - Google Patents

Abstract

PURPOSE:To make it possible to restrain generation of unburnt components after fuel supply is stopped by supplying all or greater part of the quantity of fuels from a fuel supply means located nearest to a combustion room in a predetermined period before it is shifted to a fuel supply stopped state. CONSTITUTION:An engine control unit 40 stops fuel supply from fuel injection valves 23, 26 to a fuel cut cylinder 6 during the shift of an automatic transmission 31, for softning a shock relative to the shift. Prior to the fuel-cutting, a predetermined time before the shift is changed such that in the P, S ratio to the fuel cutting cylinder 6, the proportion of the injection from a P side fuel injection valve 23 is heightened. Thus fuel injection from a S side fuel injection valve 26 at which a predetermined time before the fuel-cutting is delayed is stopped or quantitatively reduced so that residual fuels in a passage portion 12 (c) separately formed for each of cylinders is restrained from being transmitted to an actuation chamber 7 during the fuel-cutting. Therefore, unburnt gases which are exhausted to an exhaust gas passage 29 during the fuel-cutting are largely reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a fuel supply device for an engine that includes a plurality of fuel supply means and that stops fuel supply when specific operating conditions are met. This relates to control when transitioning to a fuel supply stop state.

[Conventional technology]

Conventionally, fuel supply devices have been known in which a plurality of fuel injection valves are arranged for one cylinder at different distances from the combustion chamber. ,〇- In a Talypiston engine, a plurality of independent intake passages are formed per cylinder by communicating with a plurality of intake boats opening into a working chamber corresponding to a combustion chamber, and a passageway of the first independent intake passage among them is formed. A fuel injection valve is provided near the intake boat of the second independent intake passage.

According to the structure in which the fuel injection means is arranged in this way, fuel can be supplied to the combustion chamber with good response from the fuel injection means close to the combustion chamber, while fuel can be injected from the fuel injection means located far from the combustion chamber. The injected fuel is sufficiently vaporized and atomized in the intake passage, so if you set the fuel injection ratio from each of the fuel injection valves according to the operating conditions, it will be easier to use when starting, accelerating at low speed, etc. It is possible to satisfy requirements such as responsiveness of fuel supply, acceleration of vaporization and atomization during stable operation with a relatively large amount of intake air.

[Problem to be solved by the invention]

Incidentally, it has been conventional practice to stop the fuel supply to each cylinder or some cylinders of an engine when specific operating conditions occur such that no engine output is required or it is desirable to reduce the engine output. For example, it is generally known that fuel supply is stopped during deceleration driving, and in the case of engines for vehicles equipped with automatic transmissions, it is considered that fuel supply to some cylinders is stopped during gear shifting to reduce shift shock. It is being

However, as mentioned above, for one cylinder? When stopping fuel supply under specific operating conditions in a device equipped with an M-type fuel injection valve, the following problem occurs.

That is, when transitioning from a state in which fuel is supplied to one cylinder from a plurality of fuel supply means to a state in which fuel supply is stopped, the flow of fuel from the fuel supply means close to the combustion chamber to the combustion chamber. The influx will be terminated promptly, but
The fuel supplied from the fuel supply means located far from the combustion chamber before the fuel supply is stopped flows into the combustion chamber with a delay and remains considerably in the intake passage. The fuel remaining in this intake passage flows into the combustion chamber even after the transition to the fuel supply stop state, and the air-fuel ratio becomes leaner than the one suitable for combustion.
This fuel is exhausted without being combusted within the combustion chamber. Therefore, the amount of unburned components in the exhaust gas increases due to the fuel flowing into the combustion chamber after the fuel supply is stopped, which is disadvantageous in terms of exhaust purification.
Unburned components are burned in a catalyst device for purifying exhaust gas, causing problems such as overheating of the catalyst device.

In view of the above circumstances, the present invention provides a method for controlling the flow of fuel into the combustion chamber when a plurality of fuel supply means are provided for one cylinder and the fuel supply is stopped when specific operating conditions are met. An object of the present invention is to provide a fuel supply device for an engine that can suppress the generation of unburned components after fuel supply is stopped due to a delay.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a plurality of fuel supply means (for example, fuel injection valves 23, 26) for one cylinder of the engine 1 in the combustion chamber, as shown in the configuration explanatory diagram of FIG. In the engine fuel supply device, the fuel supply device for an engine is arranged at a position where the distance from a fuel supply control means A that controls each fuel supply amount; a determination means B that determines when to transition to a specific operating condition in which fuel supply should be stopped based on detection of the operating state; and a fuel supply ratio changing means C.
It has been established that The fuel supply ratio changing means C supplies fuel from the fuel supply means closest to the combustion chamber among the plurality of fuel supply means for a predetermined period of time when transitioning to the specific operating condition determined by the determination means B. After changing the fuel supply ratio from each fuel supply means so as to increase the ratio of fuel supplied, the fuel supply is stopped. In other words, the fuel supply ratio is changed as described above at a predetermined time before the transition to the fuel supply stop state, and for example, the fuel supply ratio is changed by changing the fuel supplied from the fuel supply means closest to the combustion chamber. Either the ratio is set to 100% and fuel is supplied only from this fuel supply means, or most of the fuel to be sent to the combustion chamber is supplied from this fuel supply means.

[Effect]

According to the above configuration, during a predetermined period of time before transition to the fuel supply stop state, all or most of the fuel to be supplied to the combustion chamber is supplied from the fuel supply means closest to the combustion chamber, and this fuel is promptly supplied. By feeding fuel into the combustion chamber, less fuel remains in the intake passage when the fuel supply is stopped, and therefore less unburned components are discharged into the exhaust passage when the fuel supply is stopped. .

〔Example〕

Embodiments of the present invention will be described based on the drawings from FIG. 2 onwards.

FIG. 2 shows a schematic structure of an embodiment of the present invention.

In this figure, 1 is an engine, and the illustrated engine 1 is a three-cylinder rotary piston engine, which consists of a predetermined number of side housings 2 arranged at regular intervals and a rotor housing 3 arranged between them. Three cylinders 4.5.6 are constructed, each cylinder 4.5.6 is equipped with a rotor (not shown), and a working chamber 7 corresponding to a combustion chamber is formed between the rotor and the inner surface of the housing. ing.

A primary side intake passage 11 and a secondary side intake passage 12 are formed in the intake passage for the engine 1.
is provided with a primary side throttle valve 13 that opens and closes by movement of the accelerator pedal, and a secondary side intake passage 12 is provided with a primary side throttle valve 13 that is operated in conjunction with this when the downstream side throttle valve 13 reaches a predetermined opening degree or more. A secondary throttle valve 14 is provided which opens. - The downstream intake passage 11 and the secondary intake passage 12 are
Cylinder-specific passage sections 11a and 11b are provided on the downstream side of each cylinder.

11G, 12a, 12b, and 12C, and these cylinder-specific passage portions 11a, 11b, 11c, and 12a, 12
A primary side intake boat and a secondary side intake port at each downstream end of cylinders b and 12c open into the working chamber 7 of each cylinder 4.5°6. Further, the downstream side intake passage 11 and the secondary side intake passage 12 are gathered together on the upstream side, and the intake passage 1 upstream of the gathering part
An air cleaner 16 and an air 70-meter 17 are disposed at 5.

Cylinder-specific passage section 11a of the above-mentioned next-side intake passage 11.

11b and 11c each have a primary side fuel injection valve (hereinafter referred to as a P side fuel injection valve) 21. in a position close to the working chamber 7.
22 and 23 are arranged, and the secondary side intake passage 12
The cylinder-specific passage portions 12a, 12b, and 12c each include,
A secondary side fuel injection valve (hereinafter referred to as an S side fuel injection valve) 24°25.26 is disposed at a position farther from the working chamber 7 than the P side fuel injection valves 21 to 23. Therefore, two fuel injection valves are provided for each cylinder at 4°5.6°. Fuel injection from these fuel injection valves 21 to 26 is controlled by an engine control unit 40, which includes the air flow meter 17 and a throttle opening for detecting the throttle opening of the downstream throttle valve 13. Detection signals from a sensor 27 and a rotational speed sensor 28 that detects the engine rotational speed, and a signal from a transmission control unit 32 (to be described later) are input.

Reference numeral 29 denotes an exhaust passage, and an exhaust purification device f (not shown) such as a catalyst is provided in the exhaust passage 29.

Further, an automatic transmission 31 including a torque converter, a transmission mechanism, etc. is connected to the output side of the engine 1. This automatic transmission 31 has a 11 m
By operating in response to a control signal from the control unit 32, the gear stage is automatically shifted. Above transmission control unit 3
2 receives signals from the throttle opening sensor 27 and a vehicle speed sensor 33 that detects vehicle speed based on the transmission output shaft rotation speed, etc., and opens the throttle based on a preset shift pattern (see FIG. 6). The system performs speed change control according to the engine speed and vehicle speed.

FIG. 3 shows the internal configuration of the engine control unit 40 in a functional block diagram. The engine control unit 40 stops the fuel supply under specific operating conditions, and in this embodiment, when the automatic transmission 31 shifts, the engine control unit 40 stops the fuel supply in order to moderately suppress the engine output torque and avoid torque shock. Fuel supply is stopped only to the cylinders 6 (hereinafter, some of the cylinders 6 will be referred to as fuel cut cylinders and the other 4.5 cylinders will be referred to as non-cut cylinders). And the engine control unit 4
0 includes fuel supply control means A, determination means B, and fuel supply ratio changing means C shown in FIG.

That is, in the engine control unit 40, the driving state determining means 41 receives the detection signal of the throttle opening TVO from the throttle opening sensor 27 and the detection signal of the engine rotation speed NE from the rotation speed sensor 28.
The operating status is determined by the air flow meter 1.
Detection signal of intake air amount Qa from 7 and engine speed N
The fuel injection amount for one cylinder is calculated by a means 42 for calculating the basic fuel injection 1m based on the detection signal of E and a means 43 for calculating air-fuel ratio correction such as increase in fuel in a high rotation range or a high load range. is required. Then, the P, S injection ratio setting means 44 sets a ratio between the injection amount from the P side fuel injection valve and the injection amount from the S side fuel injection valve according to the operating state, and this ratio and the above fuel injection amount are set. Based on P for non-cut cylinders.

P of the non-cut cylinder 4°5 is determined by the S pulse width calculation means 45.
Side fuel injection valve 21.22 and S side fuel injection valve 24.2
Then, the fuel injection valve driving means 46 drives the fuel injection valves 21, 22 and 24, 25 for a time corresponding to each injection pulse width. The P and S pulse width calculation means 45 and the fuel injection valve driving means 46 for the non-cut cylinder, and the P and S pulse width calculation means 47 and the fuel injection valve driving means 48 for the fuel cut cylinder form a fuel supply control means. A is configured.

On the other hand, the gear/shift determination means 49 that receives information from the transmission control unit 32 checks the current gear and determines whether it is time to shift. The timing at which the shift is to be performed is checked in advance based on the stage, operating state, and operating state fluctuation tendency, and a pre-shift timer is set to determine the time for performing injection ratio change control before the shift. These means 49゜5
0 constitutes the determining means B.

Based on the calculation by the shift timing calculation means 50, the fuel control change determination means 51 checks whether the time until the shift timing is within the predetermined time set in the pre-shift timer. P for the fuel cut cylinder depending on the determination.

The S injection ratio setting means 52 sets the injection ratio between the P-side fuel injection valve 23 and the S-side fuel injection valve 26 of the fuel cut cylinder 6 so that the injection from the P-side fuel injection valve 23 is within the predetermined time. In accordance with the injection ratio, the P and S pulse width calculation means 47 calculates the injection pulse paddle and the fuel injection valve driving means 48 drives the fuel injection valves 23 and 26. The fuel control determining means 51 and the P and S injection ratio setting means 52 constitute a fuel supply ratio changing means C.

Furthermore, when it is time to shift based on the shift determination by the gear stage/shift determination means 49, the fuel cut time is set by the fuel cut time li1 setting means 53 so as to correspond to the time required for the shift operation of the transmission mechanism. , only during this fuel cut time, P.

The injection pulse width is set to 0 in the S pulse width calculation means 47.

FIG. 4 shows a flow chart of such control operations by the engine control unit 4°.

That is, when starting, first in step S1, the intake air amount Qa, engine rotation WINE, and throttle opening TVO are determined.
In step S2, the basic fuel injection amount (value converted to injection pulse width) Pa is calculated as -Qa/NE (where K is a conversion coefficient), and in step S3, the basic fuel injection amount (value converted to injection pulse width) Pa is calculated as The basic fuel injection IPo is multiplied by a correction aCt for increasing the amount in the load range, etc. to obtain the fuel injection amount P1.

Next, in step S4, the injection ratio between the P-side fuel injection valve and the S-side fuel injection valve is set, and each injection pulse is applied to the P-side fuel injection valve 21.22 and the S-side fuel injection valve 24.25 of the non-cut cylinder. The width pp and ps are determined by the above injection ratio [Pl-P
Calculate so that p+PS'l. This step S4
When setting the injection ratio, as shown in Figure 5,
An operating range (P
In the operating range (P+S region) where fuel is injected only from the P-side fuel injector and stable operating conditions are obtained with a large amount of intake air, the engine speed is above a predetermined rotation speed and the predetermined throttle opening is above (P+S region). The injection ratio is set according to the operating state, such as injecting 50% of the fuel from the P-side fuel injection valve and the S-side fuel injection valve, for example.

Next, in step S5, the engine speed change rate ΔNE is determined from the difference between the current engine speed N[n and the previous engine speed NEn-t. Next, in step Sa, as shown in FIG. 7, the time 11ffiT for the injection ratio change process before the shift is set in advance in association with the gear position and the rotational speed change rate ΔNE.
From the map in the memory that defines the data for m, calculate the time T according to the gear position and rotational speed change rate ΔNE at that time.
Find m and set it in the pre-shift timer. Furthermore, in step S7, the shift pattern of the automatic transmission 31 as shown in FIG.
Based on VO, the next shift rotation speed (engine rotation speed at which the next shift is performed) Sne is calculated.

In other words, assuming that the throttle opening degree TVO is constant, for example, when the vehicle speed (engine speed) increases as shown by the broken line arrow at point a in the shift pattern shown in FIG. Gear position at point a and throttle opening T
Since the shift point (point b) at which the broken line arrow crosses the shift line is determined by VO, the engine rotation speed Sne corresponding to the vehicle speed at this point b is calculated.

Next, in step S8, the difference between the shift rotation speed Sne and the current engine rotation speed NE is divided by the rotation speed change rate ΔNE to find the time from the current time until the shift is performed, and this time is determined before the shift. Check whether the time is longer than the time Tm set in the timer. And step $
If the determination in step 8 is YES, in step S9 the P-side fuel injection valve 23 and the S-side fuel injection valve 26 of the fuel cut cylinder 6 are
injection pulse width PI)1. Psl is made equal to the injection pulse widths Pp and Ps for non-cut cylinders.

When the determination in step S8 is No, in step S10, the P and 811 injection ratios for the fuel cut cylinder are set according to the gear position, rotational speed change rate ΔNE, etc. at that time. In this case, even when in the P+S injection region in FIG.
If the required fuel injection amount P1 cannot be injected by the side fuel injection valve 23 alone, the S side fuel injection valve 26 compensates for the shortage, and the proportion of injection from the P side fuel injection valve 23 is adjusted to the extent possible. Increase the size. Then, it is determined whether the fuel cut timer for setting the fuel cut time is on (step 511), and it is determined whether the shift signal sent from the transmission control unit 32 is on (step 511).
12), when these determinations are NO (before the shift is performed), in step S13,
From the injection ratio and fuel injection amount for the fuel cut cylinder determined in step 51111, the P side fuel injection valve 23 of the fuel cut cylinder 6. tj and the injection pulse widths PCz and PSt for the S-side fuel injection valve 26 are calculated.

Also, the shift signal is on (determination in step S12 is YE).
S), in step S14 the fuel cut time corresponding to the time required for the shift operation is set in the fuel cut timer, and in step S15 the injection pulse width PC for each fuel injection valve 23.26 of the fuel cut cylinder 6 is set.
z and PSl are both set to 0, and then the injection pulse width Pp1.PS1 is kept at 0 while the fuel cut timer is on (YES in step S12).

Step S9. S13. S! In step S16, each fuel injection valve 23 of the fuel cut cylinder 6 is
．． 26, an injection pulse with a pulse width of Ppl and Psl is outputted at a predetermined timing, and step Sv
Now, injection pulses with pulse widths of pp and ps are outputted to each fuel injection valve of non-cut cylinders 4 and 5 at predetermined timings, respectively.

According to the device of this embodiment as described above, the automatic transmission 31
During the shift and during normal operation excluding a predetermined time Tm before the shift, from the P side fuel injection valves 21 to 23 and the S side fuel injection valves 24 to 26 for each cylinder 4 to 6, respectively,
Fuel is supplied at the injection ratio set in step S3 according to the operating state, for example, in the P+S injection region in FIG. 4, SIIm! ! A large amount of fuel is also supplied from the fuel injection valves 24 to 26. Also, when the automatic transmission 31 is shifted, the fuel injection valve 23.2 is injected into the fuel hot cylinder 6 in the process of step S15 to alleviate the shift shock.
However, prior to such a fuel cut, at a predetermined time before the shift [Tm is the P and S injection ratios for the fuel cut cylinder 6,
Changed to increase the ratio of injection from 3 (
Step 511).

5t3).

In other words, for a predetermined period of time before the fuel cut is performed, the necessary amount of fuel is supplied to the fuel cut cylinder 6 from the P side fuel injection valve 23 which is close to the working chamber 7 and can quickly feed fuel into the working chamber 7. The fuel injection from the S-side fuel injection valve 26, in which all or most of the fuel is injected, and which is far from the working chamber 7 and causes a delay before the fuel reaches the working chamber 7, is stopped or reduced. As a result, the fuel remaining in the intake passage during the fuel cut is suppressed from being sent into the working chamber 7, and therefore, the amount of unburned gas discharged into the exhaust passage during the fuel cut is sufficiently reduced.

In addition, although the above example shows a case where fuel is cut when shifting an automatic transmission, it can also be applied to cases where fuel supply is stopped during deceleration, etc. The fuel supply may be stopped for the gold cylinder.

〔Effect of the invention〕

As described above, the present invention arranges a plurality of fuel supply means for one cylinder at different distances from the combustion chamber, and stops the fuel supply when specific operating conditions are met. In the fuel supply device, for a predetermined period of time before the fuel supply is stopped, the proportion of fuel supplied from the fuel supply means closest to the combustion chamber is increased, and the fuel is supplied from the fuel supply means located far from the combustion chamber. Since the amount of fuel is reduced, the situation where fuel supplied from a fuel supply means located far from the combustion chamber flows into the combustion chamber even after the fuel supply is stopped is suppressed, and unburned components are reduced. be able to. Therefore, it brings about effects such as improving emissions and preventing overheating of the catalyst device for purifying exhaust gas.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the configuration of the present invention, Fig. 2 is a schematic diagram of the entire device according to an embodiment of the present invention, Fig. 3 is a functional block diagram of means included in the engine control unit, and Fig. 4 is a control diagram. 5 is an explanatory diagram showing the operating status of each fuel injector according to the operating means, FIG. 6 is a diagram showing the shift pattern of the automatic transmission, and FIG. 7 is a diagram showing changes in gear position and engine speed. FIG. 4 is a diagram showing a map of injection ratio change time before fuel supply stop, which is set according to the fuel injection ratio. A... Fuel supply control means, B... Judgment means, C...
-Fuel supply ratio changing means, 1...engine, 21-2
3°24-26...Fuel injection valve (fuel supply means), 4
0...Engine control unit. Figure 1

Claims (1)

[Claims] 1. A plurality of fuel supply means are disposed for each cylinder at different distances from the combustion chamber, and fuel supply from the plurality of fuel supply means is stopped under specific operating conditions. In the engine fuel supply system,
a fuel supply control means that controls the amount of fuel supplied from each of the plurality of fuel supply means; a determination means that determines when to transition to a specific operating condition in which fuel supply should be stopped based on detection of the operating state; each of the plurality of fuel supply means so as to increase the proportion of fuel supplied from the fuel supply means closest to the combustion chamber for a predetermined period when transitioning to the specific operating condition determined by the means. 1. A fuel supply device for an engine, comprising: fuel supply ratio changing means for changing the fuel supply ratio from the fuel supply means and then shifting to a fuel supply stop state.