JPH06101521A - Control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve combustibility, reduce fuel consumption, and further improve exhaust efficiency by accurately controlling a purge flow rate so as to obtain a specified value, and promoting atomization of injected fuel. CONSTITUTION:Purge gas passing a purge control valve 39 is supplied to a header part 15 through a second purge pipe 20 and a third auxiliary fluid supply passage 19, while new air is supplied to the header part 15 through a second auxiliary fluid supply passage 16. Auxiliary fluid containing the purge gas and new air which is stored in the header part 15 is supplied to a portion around an injection port of a fuel injection valve 1. When the purge flow rate is a specified value or lower, the purge gas is supplied only to the portion around the injection port. When the purge flow rate is more than the specified value, the purge gas is supplied to the portion around the injection port and directly to an intake pipe 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine, and more particularly, to vaporization of vaporized fuel generated from a fuel tank into an intake system to suppress the vaporized fuel from being released into the atmosphere. The present invention relates to a control device for an internal combustion engine including a fuel processing system.

[0002]

2. Description of the Related Art Conventionally, a fuel tank, a canister for adsorbing and storing evaporated fuel generated from the fuel tank, a purge passage connecting the canister and an intake system of an internal combustion engine, and a purge passage interposed in the purge passage. A control device for an internal combustion engine including an evaporative fuel processing system including a flow meter and a purge control valve disposed on the downstream side of the flow meter is widely known (for example, JP-A-62-26361). Bulletin;
"First conventional example").

In the first conventional example, the evaporated fuel generated from the fuel tank is temporarily stored in the canister, and the stored evaporated fuel is purged as a combustion component into the intake system of the engine and supplied to the intake system. The evaporated fuel in the purge gas is burned in the combustion chamber together with the fuel supplied from the fuel injection valve to the intake system. Further, in the above-mentioned first conventional example, by controlling the purge flow rate supplied to the intake system by the purge control valve interposed in the purge passage, the air-fuel ratio of the air-fuel mixture in the combustion chamber is set to a desired air-fuel ratio and harmful. It suppresses the emission of components to the atmosphere.

Further, in order to promote atomization of the fuel injected from the fuel injection valve, there has already been proposed a fuel injection device in which auxiliary air is supplied from around the fuel injection valve (for example, Japanese Examined Patent Publication No. 55). -9555 gazette; hereinafter, "second
Conventional example ”).

According to the second conventional example, by supplying the auxiliary air to the vicinity of the injection port of the fuel injection valve, the injected fuel is atomized and atomization of the fuel is promoted, so that the combustibility is improved and the fuel consumption is improved. Can be reduced.

[0006]

By the way, the fuel particle diameter D
Is known to decrease as the mass flow rate u increases, as shown in FIG. On the other hand, butane, which is the main component of evaporated fuel, has a larger molecular weight than air (molecular weight of butane = 57, molecular weight of air = 28.8). Therefore, it is considered that when the evaporated fuel is supplied to the periphery of the injection port together with the auxiliary air, further atomization of the fuel is promoted.

That is, when vaporized fuel (both are referred to as "auxiliary fluid") is supplied in addition to the auxiliary air around the injection port of the fuel injection valve of the internal combustion engine having the vaporized fuel processing system, fine particles of the injected fuel are obtained. Is further promoted, and the combustibility can be further improved.

Further, in the first conventional example, when a large amount of evaporated fuel is purged into the intake system, the controllability is deteriorated and the air-fuel ratio of the air-fuel mixture is controlled to the desired air-fuel ratio with good accuracy. Therefore, there is a problem that harmful components such as HC are manipulated into the atmosphere and the exhaust efficiency is deteriorated.

Therefore, if the purge flow rate can be accurately obtained and the injected fuel can be controlled according to the purge flow rate, the air-fuel ratio of the air-fuel mixture can always be set to the desired air-fuel ratio, and the auxiliary fluid can be supplied. Further, the combustibility is further improved, and the exhaust efficiency can be improved.

The present invention has been made in view of the above circumstances, and a first object thereof is to promote further atomization of the injected fuel to improve combustibility and the like. It is to provide the control device.

A second object of the present invention is to further control the purge flow rate to a desired flow rate in addition to the above-mentioned further promotion of atomization of the injected fuel so that the air-fuel ratio of the air-fuel mixture always becomes the desired air-fuel ratio. An object of the present invention is to provide a control device for an internal combustion engine that can be controlled to further improve exhaust efficiency.

[0012]

In order to achieve the first object, a control device for an internal combustion engine according to the present invention is provided with a fuel tank, a canister for adsorbing and storing evaporated fuel generated from the fuel tank, and the canister. And a purge passage connecting the intake system of the internal combustion engine, a flow meter interposed in the purge passage, a purge control valve, and an auxiliary fluid including purge gas and fresh air passing through the purge control valve as fuel. It is characterized in that it is provided with auxiliary fluid supply means for supplying the vicinity of the injection port of the injection valve.

Further, preferably, it has an auxiliary fluid supply passage formed by branching from the purge passage, and an opening / closing valve interposed in the purge passage on the downstream side from a branch point of the auxiliary fluid supply passage. The open / close valve is closed when the purge flow rate passing through the purge control valve is equal to or lower than a predetermined value, and the open / close valve is opened when the purge flow rate is equal to or higher than the predetermined value.

Further, in order to achieve the second object, a control device for an internal combustion engine according to the present invention includes a fuel tank, a canister for adsorbing and storing evaporated fuel generated from the fuel tank, the canister and the internal combustion engine. A purge passage connecting the intake system, a flow meter interposed in the purge passage, a purge control valve, control means for controlling the flow rate of the purge gas passing through the purge control valve, and the purge control valve. An auxiliary fluid supply means for supplying an auxiliary fluid containing the passing purge gas and fresh air to the periphery of the injection port of the fuel injection valve, and the control means of the engine including at least the engine speed and the load state of the engine. An operating state detecting means for detecting an operating state; a fuel injection amount calculating means for calculating a fuel injection amount based on a detection result of the operating state detecting means;
Ratio calculating means for calculating a ratio between the fuel injection amount and the evaporated fuel amount purged from the canister based on the detection result of the operating state detecting means, and the purge control valve based on the calculation result of the ratio calculating means It has a purge control means for controlling the.

Further, preferably, there is provided an auxiliary fluid supply passage formed by branching from the purge passage, and an on-off valve interposed in an upstream purge passage from a branch point of the auxiliary fluid supply passage, When the purge flow rate passing through the purge control valve is equal to or lower than a predetermined value, the opening / closing valve is closed, and when the purge flow rate is equal to or higher than the predetermined value, the opening / closing valve is opened.

The invention according to a second object is to provide a purge flow rate calculating means for calculating a purge flow rate based on a detection result of the operating state detecting means, a calculation result of the purge flow rate calculating means and an output of the flow meter. Concentration calculation means for calculating the concentration of evaporated fuel in the purge gas based on the value, purge volume calculation means for calculating the purge volume within a predetermined period based on the output value of the flow meter, and detection by the operating state detection means Purge from the canister during the current cycle based on the dynamic characteristic calculation means for calculating the dynamic characteristic of the purge gas according to the result, the dynamic characteristic calculation means, the purge volume calculation means, and the concentration calculation means. A first evaporative fuel amount calculation means for calculating the total evaporative fuel amount, and an engine during the current cycle based on the dynamic characteristics of the total evaporative fuel amount and the purge gas. Second evaporative fuel amount calculation means for calculating the amount of intake evaporative fuel sucked into the combustion chamber, and the required fuel amount to be injected from the fuel injection valve based on the calculation result of the second evaporative fuel amount calculation means. It is also preferable that the dynamic characteristic calculated by the dynamic characteristic calculating means is different depending on the open / closed state of the open / close valve.

Further, specifically, the dynamic characteristic calculating means includes a delay time calculating means for calculating a delay time until the purge gas is purged from the canister and sucked into the combustion chamber of the engine, and the current cycle. Of the vaporized fuel purged to the intake system by the direct vaporized fuel amount calculation means for predicting and calculating the amount of direct vaporized fuel directly sucked into the engine, and the amount of attached vaporized fuel adhering to the intake system. The present invention is characterized by having a carry-away evaporated fuel amount calculating means for predicting and calculating a carry-away evaporated fuel amount to be carried away to the combustion chamber of the engine in the current cycle.

[0018]

According to the above construction, since the auxiliary fluid containing the purge gas and the fresh air is supplied to the vicinity of the injection port of the fuel injection valve, further atomization of the injected fuel is promoted.

Further, by accurately controlling the purge flow rate passing through the purge control valve, the flow rate of the auxiliary fluid can be accurately controlled.

When the purge flow rate is less than the predetermined value, the on-off valve is closed. At this time, the purge gas is supplied only to the auxiliary fluid supply means and is not directly purged to the intake system. On the other hand, since the on-off valve is opened when the purge flow rate is equal to or higher than the predetermined value, the purge gas is directly supplied to not only the auxiliary fluid supply means but also the intake system.

Further, by making the dynamic characteristics of the purge gas different depending on the open / closed state of the open / close valve, the fuel control is performed with the dynamic characteristics matched with the conveying path of the purge gas.

Further, the dynamic characteristics of the purge gas (delay time, direct evaporative fuel amount, carry-out evaporative fuel amount) have different dynamic characteristics depending on whether the on-off valve is open or closed. Due to the characteristics, the purge gas is supplied to the intake system.

[0023]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is an overall configuration diagram showing an embodiment of a control device for an internal combustion engine according to the present invention.

In the figure, reference numeral 1 denotes a DOHC in-line 4-cylinder internal combustion engine (hereinafter simply referred to as "engine") in which each cylinder is provided with an intake valve and an exhaust valve (not shown). In the engine 1, the valve timing of the intake valve and the exhaust valve (the valve opening timing and the valve lift amount) is a high-speed valve timing (high-speed V / T) suitable for the high-speed rotation region of the engine
And a low speed valve timing (low speed V / T) suitable for the low speed rotation region.

A throttle body 3 is provided in the middle of the intake pipe 2 connected to the intake port of the engine 1.
A throttle valve 3'is arranged inside thereof. Also,
A throttle valve opening degree (θTH) sensor 4 is connected to the throttle valve 3 ', and an electric signal corresponding to the opening degree of the throttle valve 3'is output to output the electric signal to an electronic control unit (hereinafter, ""ECU") 5.

A first purge pipe 6 is branched from the intake pipe 2 downstream of the throttle valve 3 ', and the first purge pipe 6 is connected to an evaporated fuel processing system 7, which will be described later. .

A branch pipe 8 is provided downstream of the first purge pipe 6 of the intake pipe 2, and an absolute pressure (PBA) sensor 9 is attached to the tip of the branch pipe 8. The PB
The A sensor 9 is electrically connected to the ECU 5, and the absolute pressure PBA in the intake pipe 2 is converted into an electric signal by the PBA sensor 9 and supplied to the ECU 5.

An intake air temperature (TA) sensor 10 is mounted on the pipe wall of the intake pipe 2 on the downstream side of the branch pipe 8. The intake air temperature TA detected by the TA sensor 10 is converted into an electric signal, and the ECU 5 Is supplied to.

The fuel injection valve 11 is provided for each cylinder between the engine 1 and the throttle valve 3'and slightly upstream of an intake valve (not shown) in the intake pipe 2. Further, each fuel injection valve 11 is connected to a fuel pump 13 via a fuel supply pipe 12 and electrically connected to the ECU 5, and the ECU 5
The valve opening time of fuel injection is controlled by the signal from.

Each fuel injection valve 11 has a single header portion 1 common to each cylinder via the respective first auxiliary fluid supply passages 14.
Connected to 5. In addition, the header portion 15 has a second
Is connected to the intake pipe 2 on the upstream side of the throttle valve 3 ′ through the auxiliary fluid supply passage 16, and an idle adjusting screw 17 and an auxiliary air amount control valve 18 are provided in the middle of the second auxiliary fluid supply passage 16. It is equipped. The auxiliary air amount control valve 18 is
It is a solenoid valve whose valve opening can be changed linearly,
5 is electrically connected and its operation is controlled by the ECU 5.

A third auxiliary fluid supply passage 19 is connected to the header portion 15 so that a purge gas from a canister 35 described later can be introduced. That is, the third auxiliary fluid supply passage 19 merges with the first purge pipe 6 and communicates with the second purge pipe 20 so that the purge gas from the canister 35 can be supplied to the header portion 15. ing. The first to third auxiliary fluid supply paths 14, 16 and 19 and the header portion 15 constitute an auxiliary fluid supply means.

An engine water temperature (TW) sensor 21 composed of a thermistor or the like is inserted into the cylinder peripheral wall filled with the cooling water of the cylinder block of the engine 1, and the engine cooling water temperature detected by the TW sensor 21 is inserted. The TW is converted into an electric signal and supplied to the ECU 5.

A crank angle (CRK) sensor 22 and a cylinder discrimination (CYL) sensor 23 are mounted around a cam shaft or a crank shaft (not shown) of the engine 1.

The CRK sensor 22 outputs a signal pulse (hereinafter referred to as "CRK") at a predetermined crank angle position with a constant crank angle cycle (for example, 30 degrees cycle) shorter than 1/2 rotation (180 degrees) of the crankshaft of the engine 1. Signal pulse), and the CYL sensor 23 outputs a signal pulse (hereinafter referred to as “CYL signal pulse”) at a predetermined crank angle position of a specific cylinder. These CRK signal pulse and CYL signal pulse are sent to the ECU 5. Supplied.

The spark plug 2 of each cylinder of the engine 1
4 is electrically connected to the ECU 5, and the ignition timing is controlled by the ECU 5. In addition, the atmospheric pressure (PA) sensor 2
The PA sensor 25 is electrically connected to the ECU 5, and supplies the detection signal to the ECU 5.

An electromagnetic valve 26 for controlling the switching of the valve timing is connected to the output side of the ECU 5, and the opening / closing operation of the electromagnetic valve 26 is controlled by the ECU 5. The solenoid valve 26 switches the hydraulic pressure of a switching mechanism (not shown) for switching the valve timing between high and low, and the valve timing has a high-speed V / T and a low-speed V corresponding to the high / low of the hydraulic pressure. / T. The hydraulic pressure of the switching mechanism is detected by a hydraulic pressure (POIL) sensor 27,
The electric signal is supplied to the ECU 5.

A catalyst device (three-way catalyst) 29 is provided in the middle of the exhaust pipe 28 connected to the exhaust port of the engine 1, and the catalyst device 29 causes HC in the exhaust gas,
Purification of harmful components such as CO and NOx is performed.

Further, a catalyst temperature (TC) sensor 30 composed of a thermistor or the like is inserted in the peripheral wall of the catalyst device 29, and the catalyst bed temperature TC detected by the TC sensor 30 is converted into an electric signal to be transmitted to the ECU 5. Is supplied to.

Further, a wide range oxygen concentration sensor (hereinafter referred to as "LA") is provided in the exhaust pipe 28 between the engine 1 and the catalyst device 29.
31 is provided. The LAF sensor 31 outputs an electric signal that is substantially proportional to the exhaust gas concentration and supplies the electric signal to the ECU 5.

Therefore, the fuel vapor processing system 7 has a fuel tank 33 having a filler cap 32 that is opened at the time of refueling the fuel, and an activated carbon 34 as an adsorbent, which is built-in for the fuel vapor from the fuel tank 33. A canister 35 for adsorbing and storing, an evaporated fuel flow passage 36 connecting the canister 35 and the fuel tank 33, and an evaporated fuel flow passage 36.
It has a two-way valve 37 composed of a positive pressure valve and a negative pressure valve which are interposed between the two.

Further, in the vaporized fuel processing system 7, a hot-wire type flow meter (hereinafter, simply referred to as "flow meter") 38 is provided in the middle of the second purge pipe 20 near the canister 35, and the flow meter is further provided. A purge control valve 39 is provided in the middle of the second purge pipe 20 downstream of 38.

The flow meter 38 utilizes the fact that when a platinum wire heated by passing an electric current is exposed to an air stream, its temperature lowers and its electric resistance decreases. And the output signal corresponding to these changes is supplied to the ECU 5.

The purge control valve 39 has a wedge-shaped valve body 40 movably arranged in the vertical direction so that the second purge pipe 20 can communicate with the purge control valve 39, and the valve body 40 is internally provided. Casing 41, a normally open solenoid valve 42 that drives the valve element 41 in the vertical direction, and a valve opening (lift) sensor (hereinafter referred to as “for PRG” connected to the valve element 41 via a valve shaft 43. L sensor ”). The solenoid valve 42 is electrically connected to the ECU 5 and duty-controls the valve lift amount of the valve body 40 in the vertical direction based on an electric signal from the ECU 5. Further, the PRG L sensor 44 is
The valve lift amount of the valve element 40 is detected and the electric signal is detected by the ECU.
Supply to 5.

A purge temperature (TP) sensor 45 is attached to the second purge pipe 20 between the flow meter 38 and the purge control valve 39. The TP sensor 45 is electrically connected to the ECU 5, and the purge temperature TP detected by the TP sensor 45 is supplied to the ECU 5.

Further, an electromagnetic opening / closing valve 46 is provided in the middle of the first purge pipe 6. The electromagnetic on-off valve 46 is an EC
The opening and closing control is performed by the signal from U5, and the first purge pipe 6
Controls the communication and disconnection of. That is, in this embodiment, when the purge flow rate passing through the purge control valve 39 is less than or equal to a predetermined value, the electromagnetic opening / closing valve 46 is closed to close the header portion 15.
Evaporative fuel is supplied only to the atomization of the fuel, while
When the purge flow rate is equal to or more than a predetermined value, the electromagnetic on-off valve 46 is opened and the intake pipe 2 is directly purged, so that the evaporated fuel is prevented from being unnecessarily accumulated in the second purge pipe 20 or the like. There is.

Therefore, the ECU 5 shapes the input signal waveforms from the various sensors described above, corrects the voltage level to a predetermined level, and converts the analog signal value into a digital signal value. , A central processing circuit (hereinafter referred to as "CPU") 5b, and storage means (including a ring buffer) 5c including a ROM and a RAM for storing various calculation programs executed by the CPU 5b and various maps and calculation results described later. And the fuel injection valve 1
1, spark plug 24, fuel pump 13, solenoid valves 26, 4
2. Output circuit 5 for supplying a drive signal to the solenoid on-off valve 46 and the like
and d.

FIG. 2 is a sectional view of the main part of the fuel injection valve 11. The fuel injection valve 11 has an auxiliary fluid introduction part 47 for introducing an auxiliary fluid around the injection port, and a lower part of the auxiliary fluid introduction part 47. And a heater section 48 that heats the injected fuel.

Specifically, the auxiliary fluid introducing section 47 is
Inlet port 49 connected to the first auxiliary fluid supply passage 14
Of the injection valve main body 51 in which a power supply line 50 connected to the ECU 5 is embedded and a nozzle 52 is provided at the tip.
Valve body 53 to which is fixed, a valve housing 54 that accommodates the valve body 53 slidably in the vertical direction, and the valve housing 5
A first support member 55 interposed between the injection valve body 51 and the injection valve body 51 to support the valve housing 54 from above;
The auxiliary fluid injection hole 56 having a substantially V-shaped cross section and the first fuel passage 5
And a second support member 58 for supporting the lower portion of the valve housing 54.

Further, the heater portion 48 has a heater casing 59 having a hole 59 ′ formed at a substantially central portion thereof, and a substantially cylindrical heater collar 61 having a second fuel passage 60 formed therein.
And a heater 62 such as a ceramic heater provided around the heater collar 61. The second fuel passage 60 has one end communicating with the first fuel passage 57 and the other end communicating with the intake pipe 2 through the hole 59 ′ of the heater casing 59. Further, the power supply line 50 is adhered to an appropriate place on the outer periphery of the heater 62, and the operation of the heater 62 is controlled by a signal from the ECU 5.

In the fuel injection valve 11 thus constructed, when the valve body 53 moves upward in the valve housing 54, the fuel injection valve 11 opens and the fuel carried from the fuel tank 33 is discharged from the nozzle 52. Is injected from the fluid chamber 63 between the injection valve main body 51 and the valve housing 54.
Is defined, and the auxiliary fluid flows from the inlet port 49 to the fluid chamber 63.
And, it is supplied to the periphery of the nozzle 52 through the auxiliary fluid injection hole 56, and atomization of the injected fuel is achieved. That is, evaporated fuel (butane) having a larger molecular weight than air is supplied to the vicinity of the injection port together with fresh air, and atomization of the injected fuel is promoted due to the reason described in the section [Operation], further improving the combustibility. Can be achieved. Further, the heating amount by the heater 62 is controlled to be larger as the engine cooling water temperature TW is lower, and atomization of the injected fuel is promoted even when the engine cooling water temperature TW is low. Then, FIG. 3 shows C
CRK signal pulse and C output from the RK sensor 22
5 is a time chart showing the generation timing of the CYL signal pulse output from the YL sensor 23 and the injection timing of the fuel injection valve.

The CRK signal pulse is transmitted to each cylinder (# 1 to # 4
For example, 24 signal pulses are generated at equal intervals, that is, a signal pulse is generated at a crank angle period of 30 °, for example, while the crankshaft makes two revolutions based on the top dead center of the piston of (CYL). Then, the ECU 5 outputs a TDC determination signal in response to the CRK signal pulse generated at the piston top dead center of each cylinder. That is, the TDC discrimination signal represents the reference crank angle position of each cylinder, and is the crankshaft 18
It occurs every 0 ° rotation. Further, the ECU 5 calculates the CRME value by measuring the generation time interval of the CRK signal pulse,
Further, the CRME value is added over the generation time interval of the TDC discrimination signal to calculate the ME value, and the engine speed NE which is the reciprocal of the ME value is calculated.

The CYL signal pulse is a predetermined crank angle position (for example, 9 degrees) before the TDC discrimination signal generating position indicating the end of the compression stroke of a specific cylinder (for example, # 1CYL).
0 ° BTDC), and a specific cylinder number (for example, for the TDC discrimination signal generation immediately after the CYL signal pulse generation)
# 1 CYL).

Further, the ECU 5 uses the TDC discrimination signal, CR
A crank angle stage (hereinafter referred to as "stage") from the reference crank angle position of each cylinder is detected based on the K signal pulse. That is, when the CRK signal pulse C1 detected when the TDC determination signal is generated occurs at the TDC position at the end of the compression process that is determined by the CYL signal pulse, the ECU 5 receives the # 1CY signal by the CRK signal pulse C1.
The # 0 stage of L is detected, and the CRK signal pulse outputted after that detects the # 1 stage, # 2 stage,
..., the # 23 stage is sequentially detected.

The injection stage at which the fuel injection should be started is set based on the operating condition of the engine, etc., and is specifically determined by executing an injection stage determination routine (not shown). The valve opening time (fuel injection time TOUT) is controlled by the setting state of the status number (SINJ (K)).

That is, the status number SINJ (K)
Is set to "2" during the opening period of the fuel injection valve 6,
It is set to "3" at the same time as the injection is completed. Then, the status number SINJ (K) is reset to “0” at the same time when the explosion stroke is entered, and is set to the injection standby state. After that, when the predetermined injection stage (for example, # 13 stage) is reached, the status number SINJ (K) is changed. After being set to "1" and a predetermined injection delay time has elapsed, the status number SINJ (K) is set to "2" and fuel is injected from the fuel injection valve 6. Then, after the fuel injection is completed, the status number SINJ (K) is set to "3" again and reset to "0" at the same time when the explosion stroke starts. Further, in this embodiment, as will be described later (see FIG. 40), the SIN
When J (K) = 3, the adhered fuel amount TWP in the intake pipe is calculated, and the fuel injection time TOUT is calculated in consideration of the adhered fuel amount TWP. The injection delay time (the time corresponding to SINJ (K) = 1) is provided at the start of the fuel injection so that the injection timing is controlled so that the injection end timing of the fuel injection and the generation of the CRK signal pulse are synchronized. This is because the end timing of the injection timing is controlled by the injection delay time.

Next, the procedure for controlling the amount of fuel supplied to the combustion chamber of the engine 1 will be described.

In this embodiment, the amount of evaporated fuel purged from the canister 35 is accurately calculated, the required amount of fuel to be supplied from the fuel injection valve 6 is calculated in consideration of the amount of evaporated fuel, and the intake pipe is also used. The final injected fuel amount to be supplied to the combustion chamber is determined in consideration of the adhered fuel amount TWP adhering to the second wall surface. Further, in this embodiment, the ratio with the fuel injection amount is calculated according to the operating state of the engine, and the valve lift command value LPU of the purge control valve 47 is calculated according to the ratio.
The CMD is determined.

Hereinafter, the control of the fuel amount will be divided into the evaporated fuel processing and the wall surface adhesion correction processing, and the program notation of JISX 0128, that is, SPD (Structured Programmi
ngDiagrams) will be described in detail based on the flow chart.

[A] Evaporative Fuel Processing FIG. 4 is a flowchart of the main routine showing the control procedure of the evaporated fuel processing.

First, in step S1, a purge area determination routine is executed to determine whether the operating condition of the engine is in the purge area. In addition, in the purge area determination routine, when it is determined that at least the purge area is present, the weight calculation mode of the evaporated fuel purged from the canister 35 is set. Here, it is known that the evaporated fuel purged from the canister 35 is mostly butane, and in the present embodiment, all the evaporated fuel in the purge gas is regarded as butane, and a series of processing is performed. That is,
As described above, when it is determined that the engine state is at least in the purge region, the flag FBCAL is set to "0" and the butane weight calculation mode is set.

Next, in step S2, the flag FBC is set.
It is determined whether AL is set to "1". When FBCAL = 1, it means that the state other than the butane weight calculation mode is set, and the process advances to step S3 to execute the zero adjustment routine to operate the flow meter 38 and the valve body 40 of the purge control valve 39. After performing the zero adjustment of the position, the process proceeds to step S7.

On the other hand, when the flag FBCAL is not "1" in step S2, that is, when FBCAL = 0,
When the butane weight calculation mode is set, the QVAPER calculating routine, the DVAPER calculating routine, and the TREQ calculating routine are executed in steps S4 to S6, and then the process proceeds to step S7. That is, Q
In the VAPER calculation routine, the purge volume (air + butane) QHWD and the butane concentration CBU in the purge flow rate within a predetermined period are calculated, and in the DVAPER calculation routine, the butane sucked in the intake stroke of this cycle based on the dynamic characteristics of the purge gas described later. In the TREQ calculation routine, the mass PGIN and the like are calculated, and in the TREQ calculation routine, the required valve opening time TRE at which the fuel injection valve 11 should be opened in the intake stroke of this cycle.
Q is calculated and the process proceeds to step S7.

Therefore, in step S7, the VPR calculation routine is executed to calculate the fuel reduction coefficient KPUN of the fuel injection amount caused by the evaporated fuel according to the operating state of the engine, and the target output voltage VHCMD of the flow meter 38. calculate. Finally, in step S8, the LPUCMD calculation routine is executed, the valve lift command value LPUCMD of the valve element 40 of the purge control valve 39 is calculated, and this program is ended.

The processing steps (subroutines) of steps S1 to S8 will be sequentially described in detail below.

Purge Area Determination (FIG. 4, Step S1) FIG. 5 is a flowchart of the purge area determination routine, and this program is executed in synchronization with the generation of the TDC determination signal.

First, in step S11, the flag FSMO is set.
It is determined whether D is "1", and it is determined whether the engine is in the start mode. Here, whether or not the engine is in the starting mode is determined by, for example, whether or not the starter switch of the engine (not shown) is on and the engine speed is equal to or lower than a predetermined starting speed (cranking speed).

When the flag FSMOD is set to "1", it is determined that the engine is in the starting mode, and the flag FCPCUT is set to "1". That is, the solenoid valve 42 is turned on and the purge control valve 39 is closed to set the purge cut condition (step S12). Then, the flag FBCAL is set to "1" to prohibit the butane weight calculation (step S13), the program is terminated, and the process returns to the main routine (FIG. 4).

On the other hand, if the flag FSMOD is "0", that is, if the engine is in the basic mode, step S14.
And whether the flag FFC is set to "1" and the engine is in the fuel cut state, or the lean correction coefficient KLS is a predetermined value other than "1", or the purge control valve 39 It is determined whether the valve lift command value LPUCMD is "0". Here, whether or not the engine is in the fuel cut state is determined based on the engine speed NE and the valve opening degree θTH of the throttle valve 3 ', and specifically, a fuel cut determination routine (not shown) is executed. Is determined by. Also, the lean correction coefficient KLS
Is set to "1" when the air-fuel ratio is other than the lean state, and is set to a predetermined value of "1" or less according to the lean state when the air-fuel ratio is the lean state. Further, the valve lift command value LPUCMD is the LP value executed in step S8.
It is calculated by the UCMD calculation routine (see FIG. 27). When none of these three conditions are satisfied, that is, FFC = 1 or KLS ≠ 1 or L
When none of the conditions PUCMD = 0 is satisfied, the routine proceeds to step S20, the flag FCPCUT is set to "0", the solenoid valve 42 is turned off, the purge control valve 39 is opened, and the fuel vapor After allowing the intake pipe 2 to be purged, the process proceeds to step S21. Step S2
At 1, the flag FBCAL is set to "0" to set the butane weight calculation mode, and then the count value nBCAL of the delay counter for calculating the butane weight (first delay counter) is set to a predetermined value N1 (for example, 16). Then (step S22), the program is terminated. The first delay counter does not immediately become “0” even if the purge cut condition (FCPCUT = 1) is satisfied in the basic mode of the engine, so that the delay delay of the system is compensated for. It is a thing. That is, when any one of the above three conditions is satisfied in step S14 in the subsequent loop, the process proceeds to step S15, the flag FCPCUT is set to "1" to set the system to the purge cut condition, and the first It is determined whether or not the count value nBCAL of the delay counter is "0" (step S16). When the count value nBCAL of the first delay counter is not "0", the process proceeds to step S18, the count value nBCAL of the first delay counter is decremented by "1", and the flag FBCAL is set to "0". Is set to the butane weight calculation mode (step S19) and the present program is terminated. On the other hand, when the count value nBCAL becomes "0" in the subsequent loop, the flag FBCAL is set to "1" to calculate the butane weight. It is prohibited (step S17), this program is terminated, and the process returns to the main routine (FIG. 4).

Thus, the flag FCPCUT is "1".
Even if the purge cut condition is satisfied, the butane weight can be continuously calculated for a predetermined period after that to deal with the system tracking delay (response delay). It is possible to improve.

Zero Adjustment (FIG. 4, Step S3) FIG. 6 is a flowchart of a zero adjustment routine. This program is executed by a timer built in the ECU 5 in synchronization with a pseudo signal pulse generated every 10 msec, for example. It

First, in step S31, the flag FCPC is set.
It is determined whether the UT is "1", and it is determined whether the purge cut state is set. When the flag FCPCUT is not "1", that is, when the purge is in progress, the process proceeds to step S40 and the count value nLPD of the delay counter for calculating a zero-point learning value (second delay counter) described later.
Is set to a predetermined value N2 (for example, 4) and the present program is ended. On the other hand, when it is determined in step S31 that the flag FCPCUT is set to "1", the purge cut is being performed and the process proceeds to step S32. , And determines whether the count value nLPD of the second delay counter is “0”. Then, in the first loop, the count value nLPD
Is not "0", the process proceeds to step S39, the count value nLPD is decremented by "1", and the program is terminated. On the other hand, when the count value nLPD becomes "0" in the subsequent loop, the process proceeds to step S33, the VHW0 calculation routine is executed, and the zero point of the flowmeter 38 is adjusted.

That is, as shown in the flow chart of FIG. 7, first, the zero point learning value VHW0REF is calculated by the equation (1).
Is calculated (step S41).

[0074]

[Equation 1] Here, CREF is 1 depending on the internal temperature of the flowmeter 38, etc.
A variable, VH, set to an appropriate value in the range of ~ 65536
W0REF (n-1) is a previously calculated value of the zero-point learning value VHW0REF, and the zero-point learning value VHW0REF is updated by performing a learning calculation on the output voltage VHW of the flowmeter 38 with the previous learning value VHW0REF (n-1). It Therefore, the zero-point learning value VHW0REF represents an average value over time.

Then, in steps S42 to S46, a limit check of the zero point learning value VHW0REF is performed, and the zero point adjustment of the flow meter 38 is completed. That is, step S
At 42, the zero point learning value VHW0REF is set to the predetermined upper limit value VH.
It is determined whether or not it is larger than W0HL, and VHW0REF>
When VHW0HL is established, the zero point VHW of the flow meter 38
While 0 is set to the predetermined upper limit value VHW0HL (step S43), when VHW0REF ≦ VHW0HL, the process proceeds to step S44 and the zero point learning value VHW0REF is set.
Is smaller than the predetermined lower limit value VHW0LL. When VHW0REF <VHW0LL is satisfied, the zero point value VHW0 is set to the predetermined lower limit value VHW0L.
While set to L (step S45), VHW0REF
= VHW0LL, the zero point value VHW0 is set to the zero point learning value VHW0REF calculated by the equation (1), the zero point adjustment of the flowmeter 38 is terminated, and the process returns to the zero point adjustment routine of FIG.

Next, in step S34 (FIG. 6), P
The current valve lift value (detection lift value) LPLIFT of the RG L sensor 44 is set to the zero point value LP of the PRG L sensor 44.
Set to 0. Next, in steps S35 to S38, a limit check of the zero point value LP0 is performed, and the zero point adjustment of the PRG L sensor 44 is completed. That is, step S
At 35, it is determined whether or not the zero point value LP0 is larger than the predetermined upper limit value LP0HL. And LP0> LP0HL
Is satisfied, the zero point value LP0 is set to the predetermined upper limit value L
While setting P0HL (step S36), LP0 ≦
If LP0HL, the process proceeds to step S37, and it is determined whether or not the zero point value LP0 is smaller than a predetermined lower limit value LP0LL. When LP0 <LP0HL is established, the zero point value LP0 is set to a predetermined lower limit value LP0LL and PRG is set.
The zero point adjustment of the L sensor 44 for use is completed (step S3
8), end this program and main routine (Fig. 4)
Return to.

QVAPER calculation (calculation of butane concentration CBU and purge volume QHWD) (FIG. 4, step S4) FIG. 8 is a flowchart of the QVAPER calculation routine, and this program is executed in synchronization with the generation of the TDC discrimination signal. .

First, at step S51, the engine speed NE, the absolute pressure PBA in the intake pipe, the atmospheric pressure PA, the purge temperature TP, and the detection lift value LPLIF of the PRG L sensor 44 are detected.
Engine parameter information such as T and the output voltage VHW of the flow meter 38 is read and stored in the storage means 5c.

Next, at step S52, the actual lift value LPACT (= LPLIFT-LP) of the PRG L sensor 44 is obtained.
0), and then in step S53, the actual output voltage VHACT (= VHW-VHW0) of the flowmeter 38 is calculated.

Next, in step S54, the QBE map is searched to calculate the first basic flow rate value QBEM.

Specifically, as shown in FIG. 9, the QBE map of the intake pipe negative pressure (gauge pressure) PBG00 to PBG15 and the PRG L sensor 44, which is the difference between the atmospheric pressure PA and the intake pipe absolute pressure PBA, is shown in FIG. Actual lift value LPACT00-L
Map values QBE in matrix for PACT15
M (00,00) to QBEM (15,15) are given. That is, the first basic flow rate value QBEM is calculated based on the well-known Bernoulli's equation by the mathematical expression (2) based on the intake pipe negative pressure PBG and the actual lift value LPACT, and the intake pipe negative pressure PBG and the actual lift value LPACT are obtained. Accordingly, the map value QBEM is given.

[0082]

[Equation 2] Here, A is the opening area of the purge control valve 39 and is expressed as a function of the actual lift value LPACT. Further, ρ is the fluid density. The first basic flow rate value QBEM is this QB
It is read by searching the E map or calculated by an interpolation method.

Next, in step S55, the QHW table is searched to calculate the second basic flow rate value QHW.

Specifically, as shown in FIG. 10, the QHW table shows the actual output voltages VHACT0 to VH of the flowmeter 38.
Table values QHW0 to QHW15 are given to ACT15. That is, the second basic flow rate value QHW is calculated based on the actual output voltage VHACT by the mathematical expression (3) based on the well-known King's equation, and the actual output voltage VH
A table value QHW is given according to ACT.

[0085]

[Equation 3] Here, A'is a pipe diameter of the first purge pipe 6, R is an electric resistance, and B and C are constants determined by the temperature and properties of the fluid, the size of the line, and the like. Then, the second basic flow rate value QHW is read by searching this QHW table,
Alternatively, it is calculated by an interpolation method.

Next, in step S56, the KTP table is searched to calculate the water temperature correction coefficient KTP of the first basic flow rate value QBEM.

As shown in FIG. 11, the KTP table is given table values KTP0 to KTP5 for the purge temperatures TP0 to TP5, and the water temperature correction coefficient KTP is searched in the KTP table. Is read out or calculated by an interpolation method.

Next, in step S57, the KPAP table is searched to calculate the atmospheric pressure correction coefficient KPAP of the first basic flow rate value QBEM.

Specifically, as shown in FIG. 12, the KPAP table is given table values KPAP0 to KPAP5 for atmospheric pressures PA0 to PA5, and the atmospheric pressure correction coefficient KPAP is searched in the KPAP table. Is read out or calculated by an interpolation method.

Then, the process proceeds to step S58, and equation (4)
The first flow rate value QBE is calculated based on the above equation, and in step S59, the ratio between the second flow rate value QHW and the first flow rate value QBE, that is, the flow rate ratio KQ is calculated based on equation (5).

QBE = QBEM × KTP × KPAP (4) KQ = QHW / QBE (5) Next, in step S60, the CBU table is searched to calculate the butane concentration CBU which is the main evaporated fuel in the purge gas.

Specifically, as shown in FIG. 13, the CBU table has a table value C for the flow rate ratios KQ0 to KQ7.
BU0 to CBU7 are given, butane concentration CBU
Is read by searching the CBU table,
Alternatively, it is calculated by an interpolation method. That is, the first flow rate value QBE is expressed by the above equation (2) based on Bernoulli's equation.
The second flow rate value QHW is calculated by the above equation (3) based on King's equation, but the second flow rate value QHW is calculated based on the actual output voltage VHACT of the flow meter 38. On the other hand, the actual output voltage VHAC of the flow meter 38
As described above, T has a structure that changes according to the butane concentration CBU that is the evaporated fuel, so the first flow rate value Q
BE and the second flow rate value QHW show different values depending on the butane concentration CBU. Therefore, the flow rate ratio K
The relationship between Q and the butane concentration CBU is stored in advance in the storage means 5c as a CBU table, and the CBU table is searched to calculate the butane concentration CBU.

Finally, based on equation (6), TD
The purge volume QHWD in the generation interval of the C determination signal is calculated, and this program is terminated.

QHWD = QHW × ME (6) As a result, the purge volume QHWD passing through the purge control valve 39 within the predetermined period is accurately calculated.

DVAPER calculation (calculation of butane mass)
(FIG. 4, Step S5) FIG. 14 is a flowchart of a DVAPER calculation routine for calculating the butane mass in consideration of the dynamic characteristics of the purge gas, and this program is executed in synchronization with the generation of the TDC determination signal.

First, in steps S71 to S79, the purge volume QHWD (i) and the butane concentration CBU.
(I), ME (i) value, and intake pipe absolute pressure PBA (i) are sequentially calculated for each cylinder and stored in the ring buffer. That is, the ring buffer BPS has a number i (i = 0 to n).
(For example, n = 15)), and the purge volume QHWD is associated with the ring buffer BPS number i.
(I), butane concentration CBU (i), ME (i) value, and intake pipe absolute pressure PBA (i) are calculated. Specifically, in step S71, the ring buffer BPS number i is "0".
If i = 0, as shown in steps S72 to S75, the purge volume QHWD, the butane concentration CBU, the ME value, and the current value of the intake pipe absolute pressure PBA are set to the buffer area of i = 0. If i = 0 other than 0, the purge volume QHW stored in the previous ring buffer number is stored as shown in steps S76 to S79.
The D (i), the butane concentration CBU (i), the ME (i) value, and the intake pipe absolute pressure PBA (i) are respectively assigned to the ring buffer number i.
The data is stored in the buffer area (i = 1 to n).

Next, in step S80, the dynamic characteristics of the purge gas are calculated.

Specifically, as shown in the flow chart of FIG. 15, first, in step S91, the purge mode is determined. That is, in the purge mode determination routine of FIG. 16, the final purge flow rate QPUCMD (LPUC of FIG. 27
Is calculated by the MD calculation routine) is a predetermined lower limit flow rate QPU
It is determined whether it is larger than CMDLM (for example, 500 cc / sec). And QPUCMD> QPUCMDLM
When is satisfied, the flag FPBAP is set to "1" (step S102), the electromagnetic opening / closing valve 46 is opened, and the purge gas can be supplied to the intake pipe 2.

On the other hand, when QPUCMD≤QPUCMDLM is satisfied, the flag FPBAP is set to "0" (step S103), the electromagnetic opening / closing valve 46 is closed to prohibit the supply of the purge gas to the intake pipe 2, and the purge gas The system is set so that can be supplied only to the header section 15.

After determining the purge mode in this way,
In step S92 (FIG. 15), it is determined whether the flag FPBAP is set to "1". And F
When PBAP = 1 is established, steps S93 to S95
Is performed to calculate the purge gas dynamic characteristics when the direct purging to the intake pipe 2 is concurrently performed, while the FPBAP is calculated.
When = 0, steps S96 to S98 are executed to calculate the purge gas dynamic characteristics when the direct purging to the intake pipe 2 is prohibited.

Specifically, when FPBAP = 1 is satisfied, the butane purged from the canister 35 while the direct purging to the intake pipe 2 is being performed in parallel in step S93 is the combustion chamber of the engine 1. The delay time τPB before reaching

The delay time τPB is given as a function of the amount of intake air passing through the inside of the first purge pipe 6. Specifically, as shown in FIG. 17, the τPB map has two parameters indicating the intake air amount, that is, the intake pipe absolute pressure PBA0.
~ PBA7 and ME0 ~ M which is the reciprocal of the engine speed
Map values τPB (0,0) to τPB (7, for E7
7) is given in a matrix form, and the delay time τ
PB is read by searching the τPB map or calculated by an interpolation method.

Then, in step S94, the BaPB map is searched to calculate the butane direct ratio BaPB at the delay time τPB.

Specifically, as shown in FIG. 18, the BaPB map is a matrix of map values BaPB (0,0) for absolute pressures PBA0 to PBA7 in the intake pipe and ME0 to ME7 which is the reciprocal of the engine speed. ~ BaPB
(7,7) is given. Where butane direct rate B
“APB” means a ratio of butane as evaporated fuel sucked into the intake pipe 2 from the canister 35 in this cycle to be directly sucked into the combustion chamber of the engine 1. Such a butane direct ratio BaPB searches the BaPB map. Read out or calculated by an interpolation method.

Next, in step S95, the BbPB map is searched for butane removal rate BbP at the delay time τPB.
Calculate B.

Specifically, as shown in FIG. 19, the BbPB map is similar to the BaPB map in that the absolute pressure PB in the intake pipe is PB.
A0 to PBA7 and ME0 which is the reciprocal of the engine speed
~ Map values BbPB for ME7 in matrix
(0,0) to BbPB (7,7) are given. Here, the butane carry-off rate BbPB means the proportion of butane as evaporated fuel that has accumulated in the intake pipe 2 and the like by the previous cycle, and is taken into the combustion chamber of the engine 1 during the current cycle, Such butane removal rate BbPB
Is read by searching the BbPB map or calculated by an interpolation method.

On the other hand, when FPBAP = 0, step S
In 96, a τA map similar to that in FIG. 17 is searched,
The delay time τA until the butane purged from the canister 35 reaches the combustion chamber of the engine 1 when the direct purging of butane to the intake pipe 2 is prohibited is calculated.

Next, in step S97, the same BaA map as in FIG. 18 is searched to calculate the butane direct ratio BaA at the delay time τA, and in step S98, a BbA map similar to that in FIG. 19 is searched to determine the delay time τA. The butane removal rate BbA at that time is calculated.

In this way, different dynamic characteristics are calculated between when the direct purging of the intake pipe 2 is performed and when it is not performed, depending on whether the direct purging is performed or not. This is because the butane transport path and the like are different, and the dynamic characteristics are also different.

Next, in step S81, the butane mass PG in the purge gas passing through the purge control valve 39 at the time of the delay time τ (τPB or τA) based on the equation (7).
Calculate T.

PGT = QHWD (τ) × CBU (τ) × DBU (7) Here, DBU is the butane density (= 2.7 kg / m ³ ) in the standard state (0 ° C., 1 atm). In this way, the total butane mass PGT in the purge gas is calculated by multiplying the purge volume QHWD by the butane concentration CBU and the butane density DBU.

Next, at step S82, the mass P of inflowing butane flowing into the combustion chamber of the engine 1 is calculated based on the equation (8).
Calculate GIN.

PGIN = Ba × PGT + Bb × PGC (8) Here, PGC represents the mass of retained butane retained in the intake pipe 2 and the like, and the initial value is set to “0”. Right side first
The term shows the mass of butane that is directly sucked into the combustion chamber among the butane that was purged in this cycle, and the second term on the right-hand side is the butane that has accumulated in the intake pipe 2 etc. up to the previous cycle. Shows the mass of butane inhaled into the chamber,
By adding both, the inflow butane mass PGIN drawn into the combustion chamber during the current cycle is calculated.

Finally, the retained butane mass PGC is calculated based on the equation (9), the present program is terminated, and the process returns to the main routine (FIG. 4).

PGC = (1-Ba) × PGT + (1-Bb) × PGC (9) The first term on the right-hand side of the butanes purged in this cycle is
The butane mass staying in the intake pipe 2 and the like is shown. The second term on the right side is the butane mass staying in the intake pipe 2 in the current cycle among the butane staying in the intake pipe 2 by the previous cycle. The accumulated butane mass PGC is calculated by adding both values.

Calculation of required valve opening time (required fuel injection time) TREQ of fuel injection valve (FIG. 4, step S6) FIG. 20 is a flowchart of the TREQ calculation routine. This program is synchronized with the generation of the TDC determination signal. Is executed.

First, in step S111, it is determined whether or not the inflow butane mass PGIN is smaller than a predetermined lower limit value PGINLM. Then, when PGIN <PGINLM is established, it is determined that the inflow butane mass PGIN can be regarded as zero, and the required fuel injection time to be injected from the fuel injection valve 11 (intake into the fuel chamber) based on the mathematical expression (10). The required gasoline amount TREQ (k) to be performed is sequentially calculated for each cylinder (# 1CYL to # 4CYL) (step S112).

TREQ (k) = Ti × KTOTAL (k) (10) Ti is the basic fuel injection time in the basic mode, and TiM is set according to the engine speed NE and the intake pipe absolute pressure PBA. Value to fuel amount correction coefficient KEG due to exhaust gas recirculation
It is calculated by multiplying R. Here, the fuel amount correction coefficient KEGR is a coefficient for correcting the fuel amount when the EGR valve provided in an exhaust gas recirculation system (not shown) is operated, and is set to a predetermined value according to the valve opening degree of the EGR valve. It Further, as the TiM map for determining the TiM value, two maps for low speed V / T and high speed V / T are stored in the storage means 5c (ROM).

Further, KTOTAL (k) is various correction coefficients (water temperature correction coefficient KTA, post-start correction coefficient KAST, target air-fuel ratio coefficient KC, which are set according to the operating state of the engine.
MD, etc.) and is set to a predetermined value for each cylinder.

On the other hand, when PGIN ≧ PGINLM, that is, when the mass of butane sucked into the combustion chamber cannot be regarded as zero, the routine proceeds to step S113, where the total air sucked in the suction stroke of the present cycle is calculated based on the equation (11). Mass GA
Calculate the IRT.

GAIRT = (α × Ti + β) × AFG × KTA (11) Ti (= TiM × KEGR) is the basic fuel injection time in the basic mode as described above, α and β are constants, and AFG is the theoretical space of gasoline. The fuel ratio (≈14.6) and KTA are water temperature correction factors. Further, in the mathematical expression (11), the total air mass GAIRT is calculated on the assumption that the fuel injection amount Y and the basic fuel injection time Ti can be approximated by a straight line. That is, the total air mass GAIRT is calculated assuming that the fuel injection amount Y is represented by Y = α × Ti + β.

Next, in each step after step S114, the mass of air consumed for butane combustion (hereinafter,
"Air mass for butane") GAIRB, air mass necessary for gasoline combustion (hereinafter referred to as "air mass for gasoline") GAIRG, and required fuel injection time TREQ (k)
Is calculated for each cylinder.

That is, in step S114, the mathematical expression (1
Calculate the butane air mass GAIRB based on 2).

[0124]

[Equation 4] Here, MAIR is the molecular weight of air (= 28.8), MBU
T is the molecular weight of butane (= 57), AFB is the theoretical air-fuel ratio of butane (≈15.5), and (1 / KTOTAL (k)) is the excess air ratio λ.

The first term on the right side shows the mass of air entrained in the inflowing butane mass PGIN, and the second term on the right side shows the mass of air required for the combustion of butane. The mass of the butane consumed by butane combustion by adding both GAIRB is calculated.

In step S115, the equation (13)
As shown in, the air mass GAAIR for gasoline is calculated by subtracting the air mass GAIRB for butane from the total air mass GAIRT.
Calculate IRG.

GAIRG = GAIRT-GAIRB (13) Finally, in step S116, the required fuel injection time T
REQ (k) is calculated, this program is terminated, and the process returns to the main routine (FIG. 4).

That is, the required fuel injection time TREQ
Since it is considered that (k) and the required gasoline amount YREQ (k) injected from the fuel injection valve 11 are in a substantially proportional relationship, the air amount GAIRG required to burn the required gasoline is the same as in step S113. It is shown by the mathematical expression (14).

GAIRG = (α × TREQ (k) + β) × AFG (14) Therefore, the formula obtained by substituting the formula (12) into the formula (13) and the formula (14) are equalized. By rearranging, the required fuel injection time TREQ (k) can be calculated as shown in the equation (15).

[0130]

[Equation 5] As a result, the required fuel injection amount to be supplied to the combustion chamber during the current cycle is obtained as a function of the fuel injection time.

VPR calculation (calculation of fuel reduction coefficient KPUN and target output voltage VHCMD of flow meter 46) (FIG. 4,
Step S7).

FIG. 21 is a flow chart of the VPR calculation routine, and this program is executed in synchronization with the generation of the TDC discrimination signal.

In steps S121 to S125, the fuel reduction coefficient KPUN is calculated. The fuel reduction coefficient KPUN is
This is for reducing the amount of fuel (gasoline amount) injected from the fuel injection valve 11 in consideration of the fact that butane, which is the evaporated fuel, is purged from the canister 35 to the intake pipe 2. First, in step S121, the KPU map Is calculated to calculate the basic fuel reduction coefficient KPUM.

Specifically, as shown in FIG. 22, the KPU map is a matrix of map values KPUM (00,00) for absolute pressures PBA00-PBA16 in the intake pipe and ME00-ME19 which is the reciprocal of the engine speed. ~ K
PUM (16, 19) is given, and the basic fuel reduction coefficient KPUM is read by searching the KPU map or calculated by the interpolation method. The basic fuel reduction coefficient KPUM is set to "1" when the flag FBCAL is set to "1" and the butane weight calculation is prohibited.

Next, in step S122, the KPUTW table is searched to calculate the water temperature correction coefficient KPUTW.

The KPUTW table is specifically shown in FIG.
As shown in, the table values KPUTW0 to KPUTW2 are given to the engine cooling water temperatures TW0 to TW4.

That is, the KPUTW table indicates that the lower the engine cooling water temperature TW, the lower the KPUTW table so that a large amount of purge gas can flow into the combustion chamber when the engine is cold started.
The water temperature correction coefficient KPUT is set to a large value.
W is read by searching the KPUTW table or calculated by an interpolation method. The water temperature correction coefficient KPUTW is also set to "1" when FBCAL = 1.

Next, in step S123, KPUAST
The table is searched to calculate the post-startup correction coefficient KPUAST.

The KPUAST table is specifically shown in FIG.
As shown in Fig. 4, after starting, the increase coefficient KAST0-KAST
Table values KPUAST0 to KPUAST2 for 4
Is given. Here, the post-starting amount increase coefficient KAST is a coefficient for increasing the amount of fuel immediately after the engine is started, and is set to a value that gradually decreases with the elapsed time after starting, and is set to "1.0" during steady operation. . As is apparent from FIG. 24, when the post-starting amount increase coefficient KAST is large, that is, when the fuel injection time is longer than at the time of starting, the post-starting correction coefficient KPUAST is set to a large value, and the post-starting correction coefficient KPUAST is set. The KPU
It is read by searching the AST table or calculated by the interpolation method. The correction coefficient KP after the start
UAST is also set to "1" when FBCAL = 1.

Next, in step S124, KPUTC
The table is searched to calculate the catalyst bed temperature correction coefficient KPUTC.

The KPUTC table is specifically shown in FIG.
As shown in, the table values KPUTC0 to KPUTC2 are given to the catalyst bed temperatures TC0 to TC4.
That is, the KPUTC table is set to a small value such that the catalyst bed temperature TC increases and the activation of the catalyst bed is promoted, and the catalyst bed temperature correction coefficient KPUTC is set to the KPUTC table.
It is read by searching the TC table or calculated by an interpolation method. The catalyst bed temperature correction coefficient KP
UTC is also set to “1” when FBUCAL = 1.

Then, in step S125, the mathematical expression (1
As shown in 6), the basic fuel reduction coefficient KPUM, the water temperature correction coefficient KPUTW, the post-starting correction coefficient KPUAST, and the catalyst bed temperature correction coefficient KPUTC are multiplied to multiply the fuel reduction coefficient KP.
Calculate UN.

KPUN = KPUM × KPUTW × KPUAST × KPUTC (16) As a result, except when the flag FBCAL is set to “1”, that is, when butane weight calculation is prohibited, immediately after the engine is started at low temperature. In the above, the water temperature correction coefficient KPUTW, the post-starting correction coefficient KPUAST, and the catalyst bed temperature correction coefficient KPUTC are all set to values larger than those during steady operation, and the butane of the light amount is mainly used immediately after the engine is cold started. A large amount of purge gas as a component can be supplied to the combustion chamber, the combustibility can be improved, and the exhaust efficiency can be improved.

Next, at step S126, the fuel injection valve 1
The limit check of the amount of gasoline injected from 1 is performed on behalf of the first cylinder (# 1CYL). That is, whether or not the valve opening time of the fuel injection valve 11 obtained by multiplying the fuel reduction coefficient KPUN calculated in step S125 is smaller than the predetermined lower limit value is determined by whether or not the mathematical expression (17) is satisfied.

Ti × KTOTAL (1) × KPUN <Be × TWP (1) + Ae × TiLIM (17) The left side shows the fuel injection time when a predetermined amount of fuel is reduced by considering the evaporated fuel, and the right side shows Item 1 is the deposited fuel amount TPW
Of these, the fuel quantity carried away to the combustion chamber during the current cycle, and the second term on the right side indicate the minimum fuel quantity of the fuel injected in the current cycle that is directly sucked into the combustion chamber. Here, Be is the final take-off rate of gasoline, which is the injected fuel, and of the fuel amount (gasoline amount) adhering to the pipe wall of the intake pipe 2 or the like, the fuel sucked into the combustion chamber during the current cycle. Says the percentage. Ae is the final direct ratio of the gasoline that is the injected fuel, and refers to the ratio of the fuel that is directly drawn into the combustion chamber during the current cycle, out of the amount of gasoline injected by the fuel injection valve 11 during the current cycle. Then, the final take-out rate Be and the final direct rate Ae are calculated by an adhesion parameter determination routine (FIG. 31) described later. Further, the adhered fuel amount TWP is calculated by a TWP calculation routine (FIG. 40) described later. Further, TiLIM is a predetermined lower limit value and is set to a lower limit value capable of maintaining linearity in relation to the fuel injection amount Y. That is,
The fuel injection time usually has a linear relationship with the fuel injection amount, but if the fuel injection time becomes extremely short, the linearity cannot be maintained and there is a risk that the fuel injection amount cannot be controlled depending on the fuel injection time. is there. Therefore, the predetermined lower limit value Ti
The LIM is set to the lower limit value that can maintain the linearity, which is the control limit of the fuel injection amount.

When the equation (17) is established, the lower limit value of the fuel reduction coefficient KPUN is set by the equation (18) (step S127).

[0147]

[Equation 6] Next, in step S128, it is determined whether or not the fuel reduction coefficient KPUN is "1". And the fuel reduction coefficient KPU
When N is "1", the flag FBCAL is set to "1" and the calculation of the butane weight is prohibited, the target butane flow rate QBUCMD is set to "0", and the routine proceeds to step S131.

On the other hand, when the fuel reduction coefficient KPUN has a value other than "1", the routine proceeds to step S130, where the mathematical expression (1
Based on 9), the target flow rate of butane as the evaporated fuel, that is, the target butane flow rate QBUCMD per unit time is calculated.

QBUCMD = (Ti × α + β) × KTOTAL (1) × (1-KPUN) × (AFG / AFB) × (1 / ME) × (1 / DBU) (19) Next, in step S131, the VHCMD table is displayed. To calculate the target output voltage VHCMD of the flow meter 46.

Specifically, the VHCMD table is shown in FIG.
As shown in, the target butane flow rate QBUCMD0 to QBU
Table values VHCMD0 to VHCM for CMD15
D15 is given, and the target output voltage VHCMD is
Is read by searching the VHCMD table or calculated by an interpolation method.

Thus, by feeding back the purge flow rate based on the target output voltage VHCMD, the canister 35 can maintain a desired adsorption capacity without causing the oversaturated state of the canister 35.

LPUCMD Calculation (Lift Command Value of Purge Control Valve 39) (FIG. 4, Step S8) FIG. 27 is a flowchart of the LPUCMD calculation routine, and this program is executed in synchronization with the generation of the TDC discrimination signal.

First, in step S141, the target output voltage VHCMD calculated in the VPR calculation routine (see FIG. 21,
The deviation ΔVH between the output voltage (detected output voltage) VHACT detected by the flow meter 38 and the step S131) is calculated. Next, in Step S122, the deviation ΔV
It is determined whether H is smaller than "0".

This is because when the purge flow rate is feedback-controlled, the purge flow rate is increased due to the spring (not shown) that elastically biases the valve body 40 of the purge control valve 39 in the valve opening direction. This is because the valve opening characteristic is different between when the flow rate is decreased and when the flow rate is increased and when the flow rate is decreased, different change speeds (gain speeds) are calculated by the deviation ΔVH, and the purge flow rate is feedback-controlled. is there.

That is, when the deviation ΔVH is smaller than "0", that is, when the flow rate is to be reduced, step S1
At 43, the KVPD map, the KVID map, and the KVDD map are searched to find the change rate of the flow rate feedback control, that is, the proportional term (P term) coefficient KVPD, the integral term (I term) coefficient KVID, and the differential term (D term) coefficient KVDD. Calculate. The KVPD map, KVID map, and KVDD map are given predetermined map values based on the engine speed NE and the intake pipe absolute pressure PBA, and the map values corresponding to the operating state of the engine are read by these map searches. , Or an interpolation method.

Next, in steps S144 to S146,
The target correction values VHP (n) and VH of the respective correction terms, that is, the P term, the I term, and the D term, are respectively calculated based on the equations (20) to (22).
I (n) and VHD (n) are calculated.

VHP (n) = ΔVH (n) × KVPD (20) VHI (n) = ΔVH (n) × KVID + VHI (n-1) (21) VHD (n) = (ΔVH (n) -ΔVH (N−1)) × KVDD (22) On the other hand, when the deviation ΔVH is larger than “0”, step S
Proceed to 147, KVPU map, KVIU map, KV
The DU map is searched to change speed of the flow rate feedback control, that is, the proportional term (P term) coefficient KVPU, the integral term (I
The term KVIU and the differential term (D term) coefficient KVDD are calculated. KVPU map, KVIU map, KVDU
Similar to the above KVPD map and the like, the map is given a predetermined map value based on the engine speed NE and the intake pipe absolute pressure PBA, and a map value corresponding to the operating state of the engine is read by searching these maps. , Or an interpolation method.

Next, in steps S148 to S150,
The target correction values VHP (n) and VH of the respective correction terms, that is, the P term, the I term, and the D term are respectively calculated based on the equations (23) to (25).
I (n) and VHD (n) are calculated.

VHP (n) = ΔVH (n) × KVPU (23) VHI (n) = ΔVH (n) × KVIU + VHI (n−1) (24) VHD (n) = (ΔVH (n) −ΔVH (N−1)) × KVDU (25) Next, in step S151, based on the equation (26), these correction terms are added to calculate the target correction value VH0BJ (n) of the output voltage in the flow rate feedback.

VH0BJ (n) = VHP (n) + VHI (n) + VHD (n) (26) Next, in step S152, the QPUCMD table is searched to calculate the target purge flow rate QPUCMD.

The QPUCMD table is specifically shown in FIG.
As shown in FIG. 8, the target correction values VH0BJ0 to VH0
Table values QPUCMD0 to QPUC for BJ15
MD15 is given, and the target purge flow rate QPU is
The CMD is read by searching the QPUCMD table or calculated by the interpolation method.

Next, in step S153, LPUCM
The D map is searched to calculate the valve lift command value LPUCMD of the purge control valve 39, and this program ends.

The LPUCMD map is specifically shown in FIG.
As shown in, the absolute pressures in the intake pipe PBA00 to PBA15
And the target purge flow rate QPUCMD00 to QPUCMD1
The map value LPUCMD (0
0,00) to LPUCMD (15,15) are given, and the valve lift command value LPUCMD is read by searching the LPUCMD map or calculated by the interpolation method.

As a result, the desired purge flow rate QPUCM
The valve lift command value LPUCMD is calculated based on D,
The valve body 40 opens according to the valve lift command value LPUCMD, and the desired purge flow rate can be drawn into the engine 1.

[B] Wall Surface Adhesion Correction Processing The required fuel injection time TREQ (k) (see FIG. 20) calculated by the above-described evaporative fuel processing considers the wall surface adhesion of gasoline, which is the injected fuel, in the intake pipe 2. However, the target fuel injection time TNET (k) needs to be calculated in consideration of such wall adhesion. Hereinafter, the wall adhesion correction process will be described in detail.

FIG. 30 is a flowchart of the wall surface adhesion correction routine, and this program is executed in synchronization with the generation of the TDC discrimination signal.

First, in step S161, the flag FV is set.
It is determined whether TEC is "0", and it is determined whether the valve timing is set to the low speed V / T. And
FVTEC = 0, that is, the valve timing is low speed V
When it is determined that the engine speed is set to / T, the LPARA determination routine is executed to set the adhesion parameter at the low speed V / T, that is, the final direct ratio Ae of gasoline as the injected fuel.
And the final take-away rate Be.

FIG. 31 is a flow chart of the LPARA determination routine for determining the adhesion parameter, and this program is executed in synchronization with the generation of the TDC discrimination signal.

First, in step S171, the A map is searched to calculate the basic direct ratio A.

As shown in FIG. 32, the A map is a matrix of map values A (0,0) to A (6) for the intake pipe absolute pressures PBA0 to PBS6 and the engine cooling water temperatures TW0 to TW6. , 6) are given, and the basic direct ratio A is read out by searching the A map or calculated by an interpolation method.

Next, in step S172, the B map is searched to calculate the basic carry-out rate B.

As shown in FIG. 33, the B map is specifically the intake pipe absolute pressures PBA0 to PBA as in the A map.
6 and engine cooling water temperatures TW0 to TW6, map values B (0,0) to B (6,6) are given in a matrix, and the basic carry-out rate B is read by searching the B map. Or calculated by an interpolation method.

Next, in step S173, the KA table is searched to calculate the rotation speed correction coefficient KA of the final direct ratio Ae.

As shown in FIG. 34, the KA table is given table values KA0 to KA4 for engine speeds NE0 to NE4, and the speed correction coefficient KA is searched for in the KA table. Read out or calculated by an interpolation method.

Next, in step S174, the KB table is searched to calculate the rotation speed correction coefficient KB of the final carry-out rate Be.

Specifically, as shown in FIG. 35, the KB table is similar to the KA table in that the table values KB0 to K corresponding to the carry-out rate rotational speed correction coefficients NE0 to NE4.
B4 is given, and the rotation speed correction coefficient KB is
It is read by searching the B table or calculated by an interpolation method.

Next, in step S175, flag F is set.
It is determined whether EGR is set to "1", and it is determined whether the operating state of the engine is in the EGR operating range. Here, whether or not it is in the EGR operation region is determined by, for example, whether or not the engine cooling water temperature TW is equal to or higher than a predetermined temperature and the engine warm-up is completed, and specifically, an EGR operation region determination routine (not shown). It is judged by executing. Then, FEGR = 1, that is, the engine is EGR
If it is determined to be in the operating region, step S176
Go to and search the KEA map to find the final direct rate Ae EG
The R correction coefficient KEA is calculated.

Specifically, as shown in FIG. 36, the KEA map is a matrix of map values KEA (0,0) to KEA (for the intake pipe absolute pressures PBA0 to PBA6 and the fuel amount correction coefficients KEGR0 to KEGR4. 6, 4) are given, and the EGR correction coefficient KEA is the KEA
It is read by searching a map or calculated by an interpolation method.

Next, in step S177, the KEB map is searched to find the EGR correction coefficient KEB for the final carry-out rate Be.
To calculate.

Specifically, the KEB map, as shown in FIG. 37, is similar to the KEA map in the intake pipe absolute pressures PBA0 to PBA0.
PBA6 and engine fuel amount correction coefficient KEGR0 to KE
Map values KEB (0,
0) to KEB (6,4), and the EGR
The correction coefficient KEB is read by searching the KEB map or calculated by the interpolation method.

On the other hand, when FEGR = 1, that is, when the engine is in the EGR non-operation region, the EGR correction coefficients KEA and KEB are set to "1.0" in steps S178 and S179, respectively.

Next, in step S180, the flag F
It is determined whether or not it is BCAL "0", and it is determined whether or not it is in the butane weight calculation mode. Then, when FBCAL = 0, that is, in the butane weight calculation mode, butane as evaporated fuel is supplied to the intake pipe 2 through the first and second purge pipes 6 and 20, and step S1
81, the calculation of the equation (27) is performed, and the fuel injection time (= Ti × K) required when the purge flow rate is “0”.
The ratio of the required fuel injection time TREQ to the total fuel injection rate TREQ, that is, the injected fuel rate KPUG is calculated.

[0183]

[Equation 7] Incidentally, in the mathematical expression (27), (1) means that the KPUG value is represented by # 1CYL by calculating only # 1CYL.

Next, in steps S182 and S183, the butane correction coefficients KVA and KVB of the final direct rate Ae and the final take-away rate Be are calculated. That is, since butane is mixed into the intake pipe 2 in addition to air, the physical properties of the fluid are considered to change, and the dynamic characteristics of the injected fuel (gasoline) are corrected by the butane.

Specifically, in step S182, KVA
Butane correction coefficient K of the final direct ratio Ae
Calculate VA.

The KVA table is as shown in FIG.
Table values KVA0 to KVA4 are given to the injected fuel rates KPUG0 to KPUG4, and the butane correction coefficient KVA is read out by searching the KVA table or calculated by an interpolation method.

Next, in step S183, the KVB table is searched and the butane correction coefficient KV of the final carry-out rate Be.
Calculate B.

The KVB table is as shown in FIG.
Similar to the KVA table, the injected fuel rate KPUG0 to KPU
Table values KVB0 to KVB4 are given to G4, and the butane correction coefficient KVB is read by searching the KVB table or calculated by an interpolation method.

On the other hand, when the flag FBCAL is set to "1", the butane weight calculation prohibit mode is set,
When butane is not purged into the intake pipe 2, the butane correction coefficients KVA and KVB are set to "1.0" in steps S164 and S185.

Then, step S186 and step S
At 187, the final direct rate Ae and the final take-away rate Be are calculated based on the equations (28) and (29), the program is terminated, and the process returns to the main routine (FIG. 30).

Ae = A × KA × KEA × KVA (28) Be = B × KB × KEB × KVB (29) Next, in step S161 of FIG. 30, the flag FV is detected.
When TEC is “1”, the process proceeds to step S163, and HP
An ARA determination routine is executed to calculate adhesion parameters (final direct rate Ae and final take-away rate Be) for high speed V / T. That is, an HPARA determination routine (not shown) substantially similar to the LPARA determination routine is executed to determine the adhesion parameter.

Next, in step S164, the flag F
It is determined whether SMOD is "1". And FSMO
When D = 1, it is determined that the engine is in the starting mode and the step S
Proceeding to 145, the final fuel injection time TOUT in the start mode is calculated based on the equation (30).

TOUT = TiCR × K1 + K2 (30) TiCR is the basic fuel injection time in the start mode,
Similar to the TiM value described above, a TiCR map that is set according to the engine speed NE and the intake pipe absolute pressure PBA and that determines the TiCR value is stored in the storage means 5c (ROM).

K1 and K2 are correction coefficients and correction variables calculated according to various engine parameter signals, respectively, and optimize various characteristics such as fuel consumption characteristics and acceleration characteristics according to the operating state of the engine for each cylinder. Is set to a predetermined value.

On the other hand, when the flag FSMOD is "0",
That is, in the basic mode, the flow from step S166 is executed for each cylinder (# 1CYL to # 4CYL). That is, in step S166, the target fuel injection time TNE is calculated based on the mathematical expression (31) for # 1CYL.
Calculate T (k).

TNET (k) = TREQ (k) + TTOTAL-Be × TWP (k) (31) Here, TTOTAL is all addition correction terms (for example, large values) calculated based on the engine operation signals from various sensors. It is the sum of the atmospheric pressure correction term TPA, etc.). However, the so-called invalid time TV of the fuel injection valve 11 is not included. TWP (k) is the intake pipe adhering fuel amount (predicted value) calculated by the flowchart of FIG. 37, which will be described later, and is (Be × TWP
(K) corresponds to the amount of carry-out fuel that the intake pipe-attached fuel is carried away into the combustion chamber. Since it is not necessary to newly inject the fuel quantity to be carried away, it is subtracted in the equation (31).

In step S167, it is determined whether or not the TNET value calculated by the mathematical expression (31) is smaller than "0". When TNET≤0, the final fuel injection time TO
The fuel supply is forcibly stopped by setting UT to 0 (step S
168) and terminates this program. When TNET> 0, the final fuel injection time TOU is calculated by the equation (32).
Calculate T.

TOUT (k) = TNET (k) / Ae × KLAF + TV (32) Here, KLAF is an air-fuel ratio correction coefficient calculated based on the output of the LAF sensor 31, and TV is the above-mentioned fuel injection valve. 11 invalid times.

By opening the fuel injection valve 6 for the final fuel injection time TOUT calculated by the equation (32), (TNET (k) × KLAF + Be × T) is set in the combustion chamber.
An amount of fuel corresponding to WP (k) is supplied.

After the fuel injection time of # 1CYL is calculated in this way, steps S166 to S169 are similarly executed for # 2CYL to # 4CYL to calculate the fuel injection time TOUT for each cylinder.

FIG. 40 shows T for calculating the adhered fuel amount TWP.
It is a flowchart of a WP calculation routine, and this program is executed for each cylinder for each predetermined crank angle (for example, every 30 °).

First, it is determined whether or not the status number SINJ (k) (see FIG. 2) is set to "3" indicating the end of injection (step S191).

If the status number SINJ (k) is set to a number other than "3", step S
In step 203, the calculation start permission flag FCTWP is set to "0".
Is set to allow the start of calculation of the adhered fuel amount TWP in the next loop, and when SINJ (k) is set to "3", it is determined whether or not the flag FCTWP is "0" (step S192). ), If the flag FCTWP (k) is "0", the flow advances to step S193 to determine whether the final fuel injection time TOUT (k) is shorter than the dead time TV. When TOUT (k) ≦ TV is satisfied, fuel is not injected, and the flag FTWPR is set.
It is determined whether or not (k) is "0", and the adhered fuel amount TWP
It is determined whether (k) cannot be regarded as "0". Then, if the flag FTWPR is set to "0" and the adhering fuel amount TWP cannot be regarded as "0", step S195.
Then, the process advances to step (33), and the adhered fuel amount TWP (k) in the current loop is calculated based on the equation (33).

TWP (k) = (1−Be) × TWP (k) (n−1) (33) where TWP (K) (n−1) is the amount of adhered fuel up to the previous loop. .

Next, in step S196, it is determined whether or not the adhered fuel amount TWP (k) is smaller than the minute predetermined value TWPLG. Then, when TWP (N) ≦ TWPLG is satisfied, the amount of deposited fuel TWP is regarded as zero and TWP is set.
(K) = 0 is set (step S197), and the flag FTWPR (K) is set to "1" (step S19).
8). Next, in step S179, the flag FCTW is set.
P is set to "1" (step S199), an instruction to end the calculation of the adhered fuel amount TWP is given, and this program is ended.

On the other hand, in step S193, TOUT (k)
> When TV is established, fuel is injected.
In step S200, the deposited fuel amount TWP (k)
Is calculated by the mathematical formula (34).

TWP (k) = (1−Be) × TWP (k) (n−1) + (1−Ae) × (TOUT (k) −TV) (34) Here, TWP (K) ( n-1) is the previous value of TWP (K). Also, the first term on the right side shows the amount of fuel that remained without being taken away this time among the fuel that was previously attached, and the second term on the right side newly attached to the intake pipe among the fuel that was injected this time. It shows the amount of fuel.

Next, the flag FTWPR is set to "1" to indicate that the adhering fuel amount TWP is present (step S
201), and further, the flag FCTWP is set to "1" to give an instruction to end the calculation of the adhered fuel amount TWP (step S202), and the present program is ended.

[0209]

As described in detail above, the control device for an internal combustion engine according to the present invention includes a fuel tank, a canister for adsorbing and storing evaporated fuel generated from the fuel tank, the canister, and an intake system of the internal combustion engine. A purge passage connecting the two, a flow meter interposed in the purge passage, and a purge control valve interposed in the purge passage in the downstream direction of the flow meter,
Since the auxiliary fluid supply means for supplying the auxiliary fluid containing the purge gas passing through the purge control valve and the fresh air to the periphery of the injection port of the fuel injection valve is provided, the purge gas having a large molecular weight and the fresh air are included. Since the auxiliary fluid is supplied to the fuel injection valve around the injection port, atomization of the injected fuel is further promoted, and it is possible to improve combustibility and reduce fuel consumption.

Further, in addition to the above structure, a control means for controlling the flow rate of the purge gas passing through the purge control valve is provided,
The control means detects the operating state of the engine including at least the engine speed and the load state of the engine, and the fuel injection amount for calculating the fuel injection amount based on the detection result of the operating state detection means. Calculating means, a ratio calculating means for calculating a ratio between the fuel injection amount and the evaporated fuel amount purged from the canister based on the detection result of the operating state detecting means, and based on the calculation result of the ratio calculating means By having the purge control means for controlling the purge control valve, the purge flow rate controlled with high accuracy according to the operating state of the engine can be supplied as auxiliary fluid to the periphery of the injection port and further to the intake system. The controllability of can be improved.

Specifically, when the purge flow rate passing through the purge control valve is below a predetermined value, the on-off valve is closed, while when the purge flow rate is above a predetermined value, the on-off valve is opened. Therefore, whether or not the evaporative fuel can be directly purged into the engine is determined according to the purge flow rate, and highly accurate air-fuel ratio control and promotion of atomization of the fuel can be performed in parallel, improving combustibility and fuel consumption. It is possible to reduce exhaust gas and improve exhaust efficiency at the same time.

Further, there is provided dynamic characteristic calculating means for calculating the dynamic characteristic (delay time, direct evaporated fuel amount, carry-away evaporated fuel amount) of the purge gas according to the detection result of the operating state detecting means, and the dynamic characteristic calculation Since the dynamic characteristics calculated by the means differ depending on the open / closed state of the on-off valve, the desired dynamic characteristics are calculated according to the operating state and the purge flow rate, and the engine always has the desired fuel characteristics that match the dynamic characteristics of the purge gas. It is possible to supply a sufficient amount, the fuel efficiency is reduced, the air-fuel ratio is stabilized, and the exhaust efficiency can be further improved.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of a control device for an internal combustion engine according to the present invention.

FIG. 2 is a sectional view of a main part of a fuel injection valve.

FIG. 3 is a time chart showing a generation timing of a CYL signal pulse, a CRK signal pulse and the like and a fuel injection timing.

FIG. 4 is a flowchart of an evaporated fuel processing routine.

FIG. 5 is a flowchart of a purge area determination routine.

FIG. 6 is a flowchart of a zero point adjustment routine.

FIG. 7 is a flowchart of a VHW0 calculation routine.

FIG. 8 is a flowchart of a QVAPER calculation routine.

FIG. 9 is a QBE map.

FIG. 10 is a QHR table diagram.

FIG. 11 is a KTP table diagram.

FIG. 12 is a KPAP table diagram.

FIG. 13 is a CBU table diagram.

FIG. 14 is a flowchart of a DVAPER calculation routine.

FIG. 15 is a flowchart of a purge gas dynamic characteristic calculation routine.

FIG. 16 is a flowchart of a purge mode determination routine.

FIG. 17 is a τPB map.

FIG. 18 is a BaPB map.

FIG. 19 is a BbPB map.

FIG. 20 is a flowchart of a TREQ calculation routine.

FIG. 21 is a flowchart of a VPR calculation routine.

FIG. 22 is a KPU map.

FIG. 23 is a KPUTW table diagram.

FIG. 24 is a KPUAST table diagram.

FIG. 25 is a KPUTC table diagram.

FIG. 26 is a VHCMD table diagram.

FIG. 27 is a flowchart of an LPUCMD calculation routine.

FIG. 28 is a QPUCMD table diagram.

FIG. 29 is an LPUCMD map.

FIG. 30 is a flowchart of a wall adhesion correction routine.

FIG. 31 is a flowchart of a LPARA determination routine.

FIG. 32 is an A map.

FIG. 33 is a B map.

FIG. 34 is a KA table diagram.

FIG. 35 is a KB table diagram.

FIG. 36 is a KEA map.

FIG. 37 is a KEB map.

FIG. 38 is a KVA table diagram.

FIG. 39 is a KVB table diagram.

FIG. 40 is a flowchart of a TWP calculation routine.

FIG. 41 is a characteristic diagram showing the relationship between mass flow rate and fuel particle size.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Intake pipe (intake system) 5 ECU (control means, dynamic characteristic calculation means) 6 First purge pipe (purge passage) 9 PBA sensor (operating state detection means) 11 Fuel injection valve 14 First auxiliary fluid Supply channel 15 Header section 16 Second auxiliary fluid supply channel 19 Third auxiliary fluid supply channel 20 Second purge pipe (purge channel) 22 CRK sensor (operating state detection means) 33 Fuel tank 35 Canister 38 Hot wire type flow meter (Flowmeter) 39 Purge control valve 46 Electromagnetic on-off valve (on-off valve)

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] November 26, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 3

[Correction method] Change

[Correction content]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

[0012]

In order to achieve the first object, a control device for an internal combustion engine according to the present invention is provided with a fuel tank, a canister for adsorbing and storing evaporated fuel generated from the fuel tank, and the canister. auxiliary and supplies a purge passage connecting an intake system of an internal combustion engine, and path over di control valve, an auxiliary fluid comprising a purge gas and fresh air the air that passes through the purge control valve to the periphery of the injection port fuel injection valves And a fluid supply means.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

Further, in order to achieve the second object, a control device for an internal combustion engine according to the present invention includes a fuel tank, a canister for adsorbing and storing evaporated fuel generated from the fuel tank, the canister and the internal combustion engine. auxiliary comprising a purge passage that connects the intake system, and path over di control valve, and control means for flow control of purge gas through the purge control valve, and a purge gas and fresh air the air that passes through the purge control valve An auxiliary fluid supply means for supplying a fluid to the vicinity of the injection port of the fuel injection valve, wherein the control means detects an operating status of the engine including at least the engine speed and a load status of the engine; Fuel injection amount calculation means for calculating the fuel injection amount based on the detection result of the operating state detection means, and the fuel injection amount based on the detection result of the operating state detection means It has a ratio calculation means for calculating a ratio with the amount of evaporated fuel purged from the canister, and a purge control means for controlling the purge control valve based on a calculation result of the ratio calculation means. There is.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0071

[Correction method] Change

[Correction content]

[0071] Zero point adjustment (Fig. 4, Step S3) A flowchart of FIG. 6 is zero point adjustment routine, the program by a timer built in the ECU 5, for example, executed in synchronism with pseudo signal pulse generated every 10msec To be done.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0209

[Correction method] Change

[Correction content]

[0209]

As described in detail above, the control device for an internal combustion engine according to the present invention includes a fuel tank, a canister for adsorbing and storing evaporated fuel generated from the fuel tank, the canister, and an intake system of the internal combustion engine. a purge passage connecting and a purge control valve interposed in a downstream direction said purge passage of the flow meter, the injection of the purge gas and fresh air the air and the fuel injection valve an auxiliary fluid comprising passing the purge control valve Since the auxiliary fluid supply means for supplying the fuel to the vicinity of the mouth is provided, the auxiliary fluid containing the purge gas having a large molecular weight and the fresh air is supplied to the fuel injection valve in the vicinity of the injection port, so that the amount of injected fuel is further improved. Atomization is promoted, so that it is possible to improve combustibility and reduce fuel consumption.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location F02M 69/00 310 E 7825-3G 69/04 G 7825-3G (72) Inventor Yasunori Ebara Saitama Prefecture 1-4-1 Chuo, Wako-shi, Honda R & D Co., Ltd.

Claims (6)

[Claims] 1. A fuel tank, a canister that adsorbs and stores evaporated fuel generated from the fuel tank, a purge passage that connects the canister and an intake system of an internal combustion engine, and a flow meter interposed in the purge passage. And an auxiliary fluid supply means for supplying an auxiliary fluid including purge gas passing through the purge control valve and fresh air to the periphery of the injection port of the fuel injection valve. Engine control unit. 2. An auxiliary fluid supply passage formed by branching from the purge passage, and an on-off valve interposed in a purge passage downstream from a branch point of the auxiliary fluid supply passage, the purge 2. The opening / closing valve is closed when the purge flow rate passing through the control valve is equal to or lower than a predetermined value, while the opening / closing valve is opened when the purge flow rate is equal to or higher than a predetermined value. Control device for internal combustion engine. 3. A fuel tank, a canister for adsorbing and storing evaporated fuel generated from the fuel tank, a purge passage connecting the canister and an intake system of an internal combustion engine, and a flow meter interposed in the purge passage. A purge control valve, a control means for controlling the flow rate of the purge gas passing through the purge control valve, and an auxiliary fluid including the purge gas passing through the purge control valve and fresh air around the injection port of the fuel injection valve. An auxiliary fluid supply means for supplying, wherein the control means detects the operating state of the engine including at least the engine speed and the load state of the engine, and based on the detection result of the operating state detecting means. Fuel injection amount calculation means for calculating the fuel injection amount by means of the fuel injection amount calculation means, and the fuel injection amount purged from the canister based on the detection result of the operating state detection means. A ratio calculating means for calculating a ratio of the fuel amount, the control system for an internal combustion engine, characterized in that it has a purge control means for controlling said purge control valve based on the calculation result of said ratio calculating means. 4. A purge control device comprising: an auxiliary fluid supply passage formed by branching from the purge passage; and an opening / closing valve interposed in the purge passage upstream from a branch point of the auxiliary fluid supply passage. 4. The internal combustion engine according to claim 3, wherein the opening / closing valve is closed when the purge flow rate passing through the valve is equal to or lower than a predetermined value, and the opening / closing valve is opened when the purge flow rate is equal to or higher than the predetermined value. Engine control unit. 5. A purge flow rate calculating means for calculating a purge flow rate based on a detection result of the operating state detecting means, and an evaporation in a purge gas based on a calculation result of the purge flow rate calculating means and an output value of the flow meter. Concentration calculating means for calculating the fuel concentration, purge volume calculating means for calculating the purge volume within a predetermined period based on the output value of the flow meter, and dynamic characteristics of the purge gas according to the detection result of the operating state detecting means. A first characteristic calculating means for calculating the total amount of evaporated fuel to be purged from the canister at the time of the current cycle based on the calculation results of the dynamic characteristic calculating means, the purge volume calculating means, and the concentration calculating means. Based on the dynamic characteristics of the total amount of evaporated fuel and the purge gas, the intake evaporated into the combustion chamber of the engine Second evaporated fuel amount calculation means for calculating the fuel amount, and required fuel amount determination means for determining the required fuel amount to be injected from the fuel injection valve based on the calculation result of the second evaporated fuel amount calculation means. 5. The dynamic characteristic calculated by the dynamic characteristic calculating means is different depending on the open / closed state of the open / close valve.
A control device for an internal combustion engine as described. 6. The dynamic characteristic calculating means calculates a delay time until the purge gas is purged from the canister and sucked into a combustion chamber of the engine, and a purge time to an intake system in a current cycle. Of the accumulated evaporated fuel, a direct evaporated fuel amount calculation means for predicting and calculating the amount of direct evaporated fuel directly sucked into the engine, and an amount of adhered evaporated fuel adhering to the intake system 6. The internal combustion engine according to any one of claims 3 to 5, further comprising: carry-away evaporative fuel amount calculation means for predicting and calculating a carry-out evaporated fuel amount to be carried away to the combustion chamber. Engine control unit.