JPH11229975A - Evaporative fuel purge quantity estimating device and fuel injection controller for engine using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a purge quantity estimating device, which can perform quick fuel injection control to an evaporative fuel mixture fuel without any complication of structure, and a fuel injection controller using this purge quantity estimating device for an engine. SOLUTION: A purge quantity estimating device arranged in an evaporative fuel purge system is provided with a canister temperature measuring means 50 detecting a temperature of a canister 20 and a computing unit computing an evaporative fuel purge quantity by using the detected canister temperature information. In this way, a purge quantity can be very easily computed and estimated on the basis of less information, and quick air-fuel ratio feed-forward control can be carried out. Therefore, generation of a time delay, which is caused in feedback control using the data from an O2 sensor arranged in an exhaust system, in fuel injection quantity control is prevented. In addition, no complication of the device structure or increase in costs is caused.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for estimating a purge amount of evaporative fuel and a fuel injection control device for an engine using the same, and more particularly to estimating a purge amount of evaporative fuel (evaporation) from a canister to an engine intake system. In addition, the present invention relates to a device that performs fuel injection control based on the control.

[0002]

2. Description of the Related Art Conventionally, there has been known an evaporative fuel purge system in which evaporative fuel generated from a fuel tank of an automobile is burned together with fuel in a combustion chamber to prevent the evaporative fuel from diffusing into the atmosphere. In such an evaporative fuel purge system, the evaporative fuel generated from the fuel tank is temporarily adsorbed by the canister, and the evaporative fuel adsorbed by the canister is supplied to the intake passage leading to the combustion chamber of the engine through the purge passage.

[0003] Evaporated fuel supplied to the intake passage through the purge passage is mixed with air to generate an evaporated fuel mixed gas. The fuel vapor mixture is mixed with the intake air sucked from the intake passage and the fuel injected from the fuel injection device to generate a final gas mixture, and the final gas mixture is burned in the combustion chamber.

The flow of fuel vapor from the canister to the intake passage is caused by the following situation. That is, first, the intake passage becomes negative pressure by the operation of the engine, and when the purge passage is opened, the other end side of the canister is opened to the atmosphere, so that air flows from the canister to the intake passage. And this flow of air desorbs the evaporated fuel adsorbed on the activated carbon in the canister,
This is because the air is guided to the intake passage through the purge passage together with the flow of the air.

In an automobile equipped with such an evaporative fuel purge system, the air-fuel ratio fluctuates because the evaporative fuel is mixed with the fuel injected from the fuel injection device. Therefore, in order to accurately adjust the air-fuel ratio to a desired value, a change in the air-fuel ratio due to the mixing of the evaporated fuel must be measured. For this reason, conventionally, the amount of evaporative fuel supplied from the canister is estimated using the output of an O2 sensor provided in the exhaust system. The fuel injection amount from the fuel injection device is adjusted based on the estimation result to obtain a desired air-fuel ratio.

In an automobile equipped with an evaporative fuel purge system, a canister purge control valve (C) is provided in consideration of the amount of evaporative fuel supplied from the canister.
Japanese Patent Application Laid-Open Nos. Hei 4-66763 and Hei 6-93 describe a technique for adjusting the opening of a PC valve to suppress fluctuations in the air-fuel ratio.
No. 932 and the like. Former Japanese Patent Application Laid-Open No. 4-6
In the technology disclosed in Japanese Patent No. 6763, the pressure of the purge evaporative fuel discharge section and the temperature of the air flowing into the canister at the time of purging are measured, and the purge evaporative fuel amount at the time of purging is actually measured based on the measurement result. ing.

In the latter technique disclosed in Japanese Patent Application Laid-Open No. Hei 6-93932, the temperature is measured by a plurality of temperature sensors disposed inside and around the canister, and the temperature difference is time-integrated to obtain the canister. The amount of evaporative fuel adsorbed on the vehicle is estimated. Then, the purge amount is adjusted based on the estimated amount of the adsorbed and evaporated fuel.

[0008]

However, the above O
In the conventional technology using two sensors, the exhaust gas after combustion is used as a control parameter. That is, since the fuel injection control for the mixture of the evaporated fuel with the air-fuel ratio is performed by the feedback control, a time delay occurs in the adjustment of the fuel injection amount. For this reason, it is difficult to accurately prevent the fluctuation of the air-fuel ratio due to the mixing of the evaporated fuel, and there is a problem that the exhaust emission characteristics are poor.

Further, in the techniques disclosed in the above-mentioned JP-A-4-66763 and JP-A-6-93932, the fuel injection control is performed by the feedforward control, so that the time delay as described above is avoided. Is done.
However, in the former case, although the accuracy is good because the amount of evaporated fuel itself is measured, the production cost associated with the provision of various sensors for that purpose increases.

In the latter case, at the initial stage of the purge start,
Since the amount of fuel vapor supplied changes abruptly in a short time, the method of controlling the opening and closing of the CPC valve by estimating the amount of fuel vapor adsorbed to the canister cannot sufficiently follow the change. Also, the configuration is complicated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a simple control system capable of controlling an air-fuel ratio by a feed-forward control having a high responsiveness in consideration of mixing of evaporative fuel. It is an object of the present invention to provide an evaporative fuel purge amount estimating device having a simple configuration and an engine fuel injection control device using the same.

[0012]

According to a first aspect of the present invention, there is provided an evaporative fuel purge amount estimating apparatus provided in an evaporative fuel purge system for detecting a temperature of the canister. And a calculating unit for estimating the purge amount of the evaporated fuel using the detected canister temperature information.

According to the present invention, the temperature of the canister rises due to an exothermic reaction when the evaporated fuel generated from the fuel tank is adsorbed on the canister, and conversely, when the evaporated fuel is purged, the temperature is increased due to the endothermic reaction. It utilizes the phenomenon of dropping, and particularly focuses on the endothermic reaction, and estimates the purge amount of the evaporated fuel supplied to the intake passage. To this end, a canister temperature measuring means and a calculation unit are provided to calculate the purge amount using the canister temperature information.

This makes it possible to calculate and estimate the purge amount of the evaporated fuel very simply and with a small amount of information.
Rapid feed-forward control of the air-fuel ratio becomes possible.
Therefore, there is no time delay in controlling the fuel injection amount as in the case of the feedback control using the data from the O2 sensor provided in the exhaust system. Further, the device configuration is not complicated, and there is almost no increase in cost. Further, the configuration does not become complicated as in the case of estimating the adsorbed amount of the evaporated fuel as in the conventional case, and poor followability to a rapid change in the purge amount does not occur.

According to a second aspect of the present invention, in the apparatus for estimating a purge amount of evaporated fuel, the calculating unit purges a value represented by a function of a purge flow rate, which is a sum of an evaporated fuel and air flow rate in a purge passage, and the canister temperature. The estimated amount of evaporated fuel is estimated.

Thus, the purge amount of the evaporated fuel can be instantaneously estimated by one arithmetic expression, and the speed of the feedforward control as described in the first aspect of the present invention is made extremely high. be able to.

According to a third aspect of the present invention, there is provided a fuel injection control device for an engine, wherein the fuel vapor generated in the fuel tank is stored in a canister, and the stored fuel vapor is purged into an engine intake passage by purged fuel vapor amount control means. 3. A fuel injection control device for an engine, comprising a purge system, wherein the purge amount of the evaporated fuel is used as one parameter of fuel injection control, wherein the purge of the evaporated fuel calculated by the purge amount estimating device according to claim 1 or 2. The fuel injection control is performed by feedforward control by estimating the amount of fuel vapor to be actually purged.

Therefore, by obtaining the above-mentioned effect according to the first or second aspect of the present invention, it is possible to perform fuel injection control without a time delay and with good followability to a change in the purge amount.

According to a fourth aspect of the present invention, there is provided a fuel injection control device for an engine, wherein the calculated fuel vapor amount is subtracted from a fuel injection amount for obtaining a target air-fuel ratio to obtain an actual fuel injection amount. I have. Therefore, after the accurate estimation of the amount of evaporated fuel with good responsiveness, fuel injection control is performed in consideration of the estimation, so that better exhaust emission characteristics can be obtained.

According to a fifth aspect of the present invention, in the fuel injection control apparatus for an engine, the purge evaporative fuel amount control means includes a purge flow rate adjusting valve provided in the purge passage and capable of adjusting the purge flow rate. The purge flow rate is adjusted by the purge flow rate control valve so that the purge flow rate has a constant mixing ratio with respect to the amount of intake air sucked into the intake passage from outside.

Thus, even if there is a sudden change in the amount of fuel vapor, the purge flow rate control valve is controlled so that the purge flow rate has a constant mixing ratio.
High-precision air-fuel ratio control with good followability becomes possible.

According to a sixth aspect of the present invention, in the fuel injection control device for an engine, the purge flow rate adjustment valve is adjusted so that the constant mixture ratio is obtained by using the engine speed and the engine load as parameters. Do. That is, the valve opening data can be easily obtained using these parameters, whereby the control of the purge flow rate adjusting valve can be performed more quickly without providing a special sensor.

According to a seventh aspect of the present invention, in the fuel injection control device for the engine, the fuel injection amount control is performed such that a basic fuel injection amount for obtaining a target air-fuel ratio and a purge flow rate with respect to intake air are constant mixing ratios. And a value represented by a function of the canister temperature information is used as a correction value of the fuel injection amount.

Therefore, the correction of the fuel injection amount is basically calculated and estimated only by the change in the temperature of the canister, so that the adjustment of the air-fuel ratio can be performed quickly and easily, and highly accurate feedforward control can be performed. Become.

According to an eighth aspect of the present invention, in the fuel injection control device for an engine, the purge evaporative fuel amount control means is constituted by a purge flow rate control valve, and the opening degree is controlled by using the engine speed and the engine load as parameters. The process is performed so as to be constant.

As in the case of the sixth aspect, the valve opening data can be easily obtained using the above parameters, whereby the control of the purge flow rate adjusting valve can be performed more quickly without providing a special sensor. Therefore, the correction control of the fuel injection amount is quicker and simpler.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an engine system for a vehicle equipped with a device for estimating a purge amount of evaporated fuel and a fuel injection control device for an engine using the same according to an embodiment of the present invention.

The engine body 10 is provided with an intake passage 12 and an exhaust passage 14, and an injector 18 as a fuel injection means is provided for each cylinder and connected to a fuel tank 16. Also, an electronic control unit (ECU) 24 is provided as a control unit for adjusting each unit of the engine system, and receives detection signals from various sensors and outputs control signals for operating the engine.

The fuel vapor purging system has a main component, a canister 20, which is connected to a fuel tank 16 through a two-way valve 27 so as to adsorb the fuel vapor generated in the fuel tank 16. I have. The evaporative fuel discharge side of the canister 20 is a purge passage 23 which is connected to the intake passage 12 of the engine via a canister purge control valve 22 (hereinafter referred to as a CPC valve) as a purge evaporative fuel amount control means. . In the purge passage 23, a purge flow rate H1 flowing through the purge passage 23 (evaporated fuel amount FE + inflowing air amount AE
) Is provided. The measurement data is sent to the ECU 24.

The interior of the canister 20 is made of activated carbon, on which the fuel vapor generated in the fuel tank 16 is adsorbed. Since the end of the canister 20 is open to the atmosphere, the inside of the intake passage 12 of the engine becomes negative pressure by the operation of the engine, so that the evaporated fuel adsorbed by the canister 20 is drawn to the intake passage 12 together with the outside air (air). The mixture flows into the purge passage 23 in a mixed state.

Further, as one characteristic component of the present invention, the canister 20 is provided with a canister temperature sensor 50. The temperature of the canister 20 rises due to an exothermic reaction when the evaporative fuel is adsorbed by the activated carbon therein, and decreases when the evaporative fuel separates from the activated carbon and flows into the purge passage 23. This temperature change is detected by the canister temperature sensor 50.

The CPC valve 22 is constituted by, for example, a duty solenoid valve and is controlled by the ECU 24. That is, the CPC valve 22
The purge flow rate H1 of the fuel vapor mixture flowing from the canister 20 to the purge passage 23 is adjusted.

The combustion chamber of the engine body 10 is supplied with the intake air mixed with the evaporated fuel gas mixture from the purge passage 23 and the final mixed gas mixed with the fuel injected from the injector 18. The mixed gas is burned from the ignition plug 26.

The fuel injection control device for adjusting the fuel injection amount has an injector 18 for performing fuel injection and an ECU 24 for controlling the injection pulse width of the injector 18.

The crank angle is detected by the crank angle sensor 56 among the various sensors installed on the engine body 10 to calculate the engine speed. These various sensors send detection data to the ECU 24.

A chamber 28, an air cleaner 30, and an air flow sensor 32 for measuring the amount of intake air are provided on the upstream side of the intake passage 12 on the air intake side. The detection data from the air flow sensor 32 is EC
Output to U24. A throttle body 34 including a throttle valve is provided at an intermediate portion of the intake passage 12, and a throttle sensor 36 and an ISC valve 38 are provided near the throttle body 34, respectively.

On the other hand, a catalyst 40, an exhaust muffler 42, and an O2 sensor 44 for detecting the concentration of oxygen in the exhaust gas burned in the combustion chamber are provided upstream of the catalyst 40 in the exhaust passage 14. The detection data from the O2 sensor 44 is output to the ECU 24.

As described above, in the present embodiment, the fuel vapor purge system includes the canister 20, the canister temperature sensor 50, the purge passage 23, the CPC valve 22, and the EC.
U24 has a basic configuration.

FIG. 2 shows the configuration of the ECU 24. As shown, a central processing unit (CPU) 24a for performing arithmetic processing, a ROM 24b for storing a predetermined data program, etc., and temporarily storing data that needs to be rewritten. A RAM 24c for storing, a backup RAM 24d for storing and holding rewrite data, other A / D converters 24e,
Drive circuit 24f, I / O port 24g, bus line 24
h and a power supply circuit 24i.

The driving circuit 24f is provided with the CPC valve 2
2 and also functions as a drive circuit for the injector 18, and in this embodiment, outputs a signal for correcting and controlling the fuel injection amount.

Next, the operation of the evaporative fuel purge system having the above-described structure and the operation of the fuel injection control device for the engine using the same will be described in detail with reference to FIGS. FIG.
Is a flowchart (step (hereinafter simply referred to as “S”) showing an example of a flowchart showing an operation of controlling the opening degree of the CPC valve 22 performed using predetermined parameters for controlling the purge flow rate.
FIG. 4 is a flowchart showing the fuel injection control operation (S201 to S20).
4) and FIG. 5 are conceptual diagrams showing control parameters.

First, in the control of the opening degree of the CPC valve 22 shown in FIG. 3, when the engine body 10 operates, the pressure in the intake passage 12 becomes negative, and air is sucked into the intake passage 12 through the air cleaner 30. As shown in FIG. 5, the intake air amount AM sucked from the intake passage 12 is detected by the air flow sensor 32 (S101), and this detection data is output to the ECU 24.

The engine speed N is determined by the crank angle sensor 56.
(S102), and the detection data is
Is output to When the intake air amount AM is detected, ECU
In step S103, a fuel injection amount, that is, a basic fuel injection amount TP is calculated by calculation so that the stoichiometric air-fuel ratio (14.7) with respect to the detected intake air amount AM. In the case of a so-called gasoline engine, the fuel injection amount TP is calculated by the following equation.

Intake air amount (AM) / basic fuel injection amount (TP) = 14.7 Next, the opening of the CPC valve 22 is retrieved (S10).
4). This search is performed by searching from a map as illustrated in advance stored in the ROM 24b based on the engine speed N and the engine load. As the engine load, the basic fuel injection amount TP or the pressure in the suction pipe is used.

This map is used for searching the CPC
The opening degree of the valve 22 is determined by the purge flow rate H1 flowing through the purge passage 23 (evaporated fuel amount FE + inflow air amount A) with respect to the intake air amount AM detected by the air flow sensor 32.
E) is set to have a constant mixture ratio EM.
That is, the CPC valve 2 set by this map
With the opening degree of 2, the CPC valve 22 becomes H1 / AM = E
It is controlled to be M (constant).

Then, a control signal for adjusting to the searched opening is output from the ECU 24, and the opening of the CPC valve 22 is adjusted (S105).

Next, a fuel injection control operation performed in consideration of the supplied evaporated fuel will be described. First, as described above, when the engine operation is started, air is sucked into the intake passage 12 shown in FIG. That is, when the CPC valve 22 is opened, the end of the canister 20 is open to the atmosphere, so that air flows from the canister 20 to the intake passage 12 through the purge passage 23. This air flow is the canister 2
The evaporated fuel adsorbed on the activated carbon of No. 0 is released, and the evaporated fuel mixed gas in which the evaporated fuel and the air are mixed flows through the purge passage 23.

Here, the temperature of the canister 20 drops when the fuel vapor is released from the activated carbon of the canister 20, and the temperature of the canister 20 decreases more as the amount of the fuel vapor released increases. The canister temperature sensor 50 measures the temperature TC of the canister 20.

First, the canister temperature TC is detected by the canister temperature sensor 50 as a first operation of the fuel injection control (correction control in consideration of the evaporated fuel). This detection result is output to the ECU 24. As described above, since the temperature TC of the canister 20 depends on the amount of evaporated fuel FE supplied (leaved) from the canister 20, the amount of evaporated fuel FE is expressed by the following equation relating to the canister temperature TC.

Evaporated fuel amount FE = (K1 × H1) .TC +
(K2 × H1) In this equation, each of K1 and K2 is an adaptation constant for each system that changes depending on the capacity of the engine body 10, the canister 20, the length of the purge passage 23, and the like. Also,
The purge flow rate H1 is based on measurement data from the purge flow rate measuring means 25. By calculating the amount of evaporated fuel in accordance with this equation, a rapid change in the amount of evaporated fuel FE at the beginning of the start of the evaporated fuel purge can be detected quickly and without a time lag. That is, it can be detected as a change in the temperature TC of the canister 20 and the purge flow rate H1.

Then, the fuel vapor amount F thus calculated
E is estimated as the evaporated fuel supplied to the intake passage 12,
The fuel injection amount can be corrected quickly and accurately by reducing the amount of the evaporated fuel with respect to the basic fuel injection amount TP for obtaining the stoichiometric air-fuel ratio.

Further, the fuel injection amount correction control for correcting the above-described fuel injection amount and calculating the final actual fuel injection amount will be described with reference to FIG. FIG. 2 is a flowchart showing the control operation. First, as a first operation of the fuel injection control (correction control in consideration of the evaporated fuel),
The canister temperature is detected by the canister temperature sensor 50 (S201).

Next, an operation for calculating a vaporized fuel correction term for correcting the fuel injection amount, that is, a corrected fuel injection amount α, for the basic fuel injection amount TP for obtaining the stoichiometric air-fuel ratio calculated in advance is performed. (S202). Corrected fuel injection amount α
Is determined by the following equation. That is, "α" is calculated based on the constant mixing ratio EM and the temperature TC of the canister 20.

Evaporated fuel correction term α = TP · EM · [｛(K
TC × TC) + KT} -1] In the above equation, each of KTC and KT is an adaptation constant for each system. When the corrected fuel injection amount α is calculated, the actual fuel injection amount Ti actually injected from the injector 18 is determined by the following equation based on the previously calculated basic fuel injection amount TP and corrected fuel injection amount α. (S20
3).

Actual fuel injection amount Ti = Basic fuel injection amount Tp−
Corrected fuel injection amount α These series of calculation processes are executed by the ECU 24 constituting the fuel injection control device. Then, the injector 18 is controlled based on the calculated actual fuel injection amount Ti (S204). Therefore, the injector 18 quickly responds to the change in the evaporative fuel amount based on the change in the temperature TC of the canister 20. Corrected accordingly and injects the correct amount of fuel. In other words, the fuel injection amount is adjusted by feedforward control instead of feedback control using the data of the O2 sensor as in the related art.

As described above, according to the purge amount estimating apparatus according to the embodiment of the present invention, the canister temperature TC
, And the detected data and the measured purge flow rate H
1 to calculate and estimate the amount of evaporated fuel FE supplied to the intake passage 12, and it is possible to detect a change in the amount of evaporated fuel FE with extremely high responsiveness.

Further, based on only the canister temperature TC, the fuel injection amount accompanying the mixing of the evaporated fuel can be corrected. That is, when the temperature TC of the canister 20 is high, the fuel injection amount from the injector 18 is adjusted in the increasing direction, and when the temperature of the canister 20 is low, the fuel injection amount is adjusted in the opposite decreasing direction. Therefore, quick feedforward control is achieved.

Further, the opening degree of the CPC valve 22 is controlled such that the purge flow rate H1 supplied to the intake passage 12 becomes a constant mixing ratio (EM) with respect to the air flow rate AM in the intake passage 12. It is assumed that Therefore, even if there is a sudden change in the amount of evaporative fuel, the CPC valve 22 is controlled so that the purge flow rate becomes a constant mixing ratio. Has become.

[0059]

As described above, according to the evaporative fuel purge amount estimating apparatus and the engine fuel injection control apparatus using the same according to the present invention, the calculation of the supplied evaporative fuel amount is performed with good responsiveness. Therefore, the correction control of the fuel injection amount based on this can be performed quickly and accurately, and the fuel injection amount can be accurately corrected only by the canister temperature, so that the exhaust emission characteristics can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an engine system including an embodiment of the present invention.

FIG. 2 is a block diagram of an electronic control unit of the engine system of FIG.

FIG. 3 is a control flowchart of a CPC valve opening degree according to the embodiment.

FIG. 4 is a control flowchart for performing correction control of a fuel injection amount by a fuel injection control device.

FIG. 5 is a conceptual diagram showing each control parameter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Engine main body 12 Intake passage 20 Canister 22 CPC valve 23 Purge passage 24 ECU 25 Purging flow rate measuring means 50 Canister temperature sensor

Claims (8)

[Claims] An evaporative fuel purge system for storing evaporative fuel generated in a fuel tank in a canister and purging the stored evaporative fuel into an engine intake passage through a purge passage by a purge evaporative fuel amount control means; A canister temperature measuring means for detecting the temperature of the fuel injection amount, and a calculation unit for calculating the purged evaporated fuel amount as a correction value used for correction control of the fuel injection amount using the detected canister temperature information. An apparatus for estimating a purge amount of evaporated fuel, characterized in that: 2. A purge flow rate measuring means for measuring a purge flow rate which is a sum of an evaporative fuel flow rate and an air flow rate in the purge passage, wherein the calculation by the calculation unit is performed based on the measured purge flow rate and the canister temperature. 2. The evaporative fuel purge amount estimating apparatus according to claim 1, wherein the estimating is performed by setting a value represented by a function as the purged evaporative fuel amount. 3. An evaporative fuel purge system for storing evaporative fuel generated in a fuel tank in a canister and purging the stored evaporative fuel into an engine intake passage by means of a purge evaporative fuel amount control means, wherein the purge amount of the evaporative fuel is provided. A fuel injection control device for an engine, wherein the amount of fuel vapor calculated by the purge amount estimating device according to claim 1 or 2 is estimated as an amount of fuel vapor to be actually purged. A fuel injection control device for an engine, wherein a basic fuel injection amount for achieving a target air-fuel ratio is corrected and controlled. 4. The fuel injection control device for an engine according to claim 3, wherein the calculated fuel vapor amount is subtracted from the basic fuel injection amount to obtain an actual fuel injection amount. 5. The purge evaporative fuel amount control means includes a purge flow rate adjusting valve provided in the purge passage and capable of adjusting the purge flow rate, and the intake air sucked from the outside into the intake passage of the engine. 6. The fuel injection control of an engine according to claim 4, wherein the purge flow rate is adjusted by the purge flow rate control valve so that the purge flow rate has a constant mixing ratio with respect to the air amount. apparatus. 6. The purge flow rate adjusting valve according to claim 5, wherein an opening degree of the purge flow rate adjusting valve is adjusted by using an engine speed and an engine load as parameters so as to obtain the constant mixing ratio. Engine fuel injection control device. 7. An evaporative fuel purging system for storing evaporative fuel generated in a fuel tank in a canister and purging the stored evaporative fuel into an engine intake passage through a purge passage by a purge evaporative fuel amount control means. In a fuel injection control device for an engine that performs fuel injection amount control in consideration of a purge amount, a canister temperature measuring unit that detects a temperature of the canister; and a purge flow rate that is a sum of an evaporative fuel and an air flow rate in the purge passage. And a purge flow rate measuring means for measuring, wherein the evaporated fuel purged by the purged evaporated fuel amount control means is performed by adjusting a purge flow rate in the purge passage, and the amount of intake air in an intake passage of the engine is adjusted. On the other hand, the purge flow rate is controlled so as to have a constant mixing ratio, and the fuel injection amount control Basic fuel injection amount for obtaining a ratio, fuel injection control apparatus for an engine, wherein a value expressed by a function of the temperature information of the certain mixing ratio and the canister to the correction value of the fuel injection amount. 8. The purge evaporative fuel amount control means includes a purge flow rate adjusting valve provided in the purge passage and capable of adjusting the purge flow rate. 8. The fuel injection control device for an engine according to claim 7, wherein the opening degree is adjusted so that the constant mixing ratio is obtained.