JPH07109941A - Fuel controller of engine - Google Patents

Abstract

PURPOSE:To provide the fuel controller of an engine capable of preventing shift of an air-fuel ratio caused by purge fuel by surely detecting a purge fuel quantity. CONSTITUTION:A fuel control means for controlling a fuel injection quantity Tinj based on the output of a throttle opening sensor 11, an engine rotational sensor 36, etc., a canister 20 adsorbing a fuel steam gas from a fuel tank 19, a HC concentration sensor 25 provided in a canister fluid passage 16, and intake differential pressure detection means 24, 18 provided in the fluid passage 16, for detecting differential pressure (Pc-Pa) between an intake system 3 of the engine and an adhesive means are provided. Consequently, a steam fuel quantity calculation means for calculating a purge fuel quantity fPN sucked into the intake passage 3 of the engine through the fluid passage 16 based on the differential pressure (Pc-Pa) and the HC concentration Vc, and the fuel correction means for correcting the fuel injection quantity Tinj by the fuel control means based of the calculated result are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel control device for an engine equipped with a device for preventing atmospheric release of fuel evaporative emission from a fuel tank, and more particularly to adsorbing fuel evaporative emission from a fuel tank onto an adsorbing means. The present invention relates to a fuel control device for an engine, which causes the fuel evaporative gas of the adsorption means to flow into the engine intake system as fuel in a timely manner.

[0002]

2. Description of the Related Art Conventionally, a device for preventing atmospheric release of fuel evaporative emission (HC) from a fuel tank has been widely used. In this device, the fuel evaporative gas from the fuel tank is adsorbed and held by an adsorbing means such as a canister, and the fuel evaporating of the canister is passed through a passage connecting the adsorbing means and the intake system of the engine during high load operation of the engine. The gas is made to flow into the intake system so that it can be effectively used as fuel. By the way, the engine originally
The amount of fuel is controlled so as to maintain a predetermined air-fuel ratio, and when the fuel evaporative gas adsorbed in the canister is introduced into the combustion chamber from the intake system of the engine, the combustion atmosphere in the combustion chamber becomes rich. It will be. Therefore, the time when the fuel evaporative gas adsorbed in the canister is caused to flow into the combustion chamber, that is, the purge time is usually set to the high load operation range where the enrichment operation is performed. The purging process is performed without any discomfort in the driving performance.

On the other hand, when the engine is operating at low and medium loads, it is desirable to achieve stoichiometric or lean operation in view of engine operating performance, fuel economy, and exhaust gas measures. In this operating range, purging, that is, enrichment is performed. There are many problems in operating with the air-fuel ratio, and in this operating range, the fuel evaporative gas is adsorbed to the canister. By the way, during the purge operation, the air-fuel ratio becomes rich, and if the air-fuel ratio is excessively deviated, drivability deteriorates, and deterioration of exhaust gas is likely to occur.Thus, the amount of fuel evaporative gas to be purged is obtained, It is known to correct the fuel supply. For example, JP-A-2-2454
As disclosed in Japanese Patent Publication No. 41, the basic fuel injection amount is calculated based on the output of the air-fuel ratio sensor, the purge fuel amount detection means detects the purge fuel amount, and the fuel injection amount correction means calculates the basic fuel injection amount from the basic fuel injection amount. The purged fuel amount is subtracted, and the fuel injection control means performs fuel injection according to the result to prevent the deviation of the air-fuel ratio.

[0004]

However, in this conventional apparatus, it is not disclosed what structure the purge fuel amount detecting means adopts to detect the purge fuel amount. Moreover, here, when the air-fuel ratio is near stoichio, the purge correction coefficient is not modified, so that the purge correction coefficient is not modified when the air-fuel ratio shifts to near stoichio during lean operation, It becomes rich and causes problems. An object of the present invention is to provide a fuel control device for an engine that can reliably detect the amount of purged fuel and prevent the deviation of the air-fuel ratio due to the purged fuel.

[0005]

In order to achieve the above object, the present invention comprises means for detecting the operating state of an engine,
Fuel control means for controlling the fuel injection amount based on the output of the detection means, adsorbing means for adsorbing the fuel evaporative gas generated from the fuel tank, a flow path communicating the adsorbing means with the intake system of the engine, HC concentration detecting means provided in the flow path for detecting the concentration of the fuel vaporized gas sucked into the intake system of the engine from the adsorbing means, and a difference between the intake system of the engine and the adsorbing means provided in the flow path. The intake differential pressure detecting means for detecting the pressure, and the fuel amount of the fuel evaporative gas sucked into the intake system of the engine through the flow path based on the detection results of the HC concentration detecting means and the intake differential pressure detecting means. And a fuel correction unit that corrects the fuel injection amount by the fuel control unit based on the calculation result of the evaporated fuel amount calculation unit.

A second aspect of the present invention is a means for detecting the operating state of the engine, a fuel control means for controlling the fuel injection amount based on the output of the detection means, and an adsorption means for adsorbing the fuel evaporative gas generated from the fuel tank. Means, a flow path communicating the adsorbing means with the intake system of the engine, and an HC concentration detecting means provided in the flow path for detecting the concentration of the fuel evaporative gas sucked into the intake system of the engine from the adsorbing means. And an intake differential pressure detection means for detecting a differential pressure between the intake system of the engine and the adsorption means provided in the flow path, and the flow based on the detection results of the HC concentration detection means and the intake differential pressure detection means. An evaporative fuel amount calculation means for calculating the fuel amount of the fuel evaporative gas sucked into the intake system of the engine through the passage, a surge tank arranged on the downstream side of the intake system with the passage open, and the evaporation Evaporative fuel amount correction calculation means for correcting and calculating the fuel amount calculated by the charge amount calculation means in accordance with a delay time until the fuel evaporative gas is sucked into the combustion chamber of the engine through the flow path, And a fuel correction unit that corrects the fuel injection amount by the fuel control unit based on the calculation result of the evaporated fuel amount correction calculation unit.

[0007]

According to the present invention, the HC concentration detecting means detects the concentration of the fuel evaporative gas sucked into the intake system of the engine from the adsorbing means for adsorbing the fuel evaporative gas, and determines the differential pressure between the intake system of the engine and the adsorbing means. The intake differential pressure detection means detects, and based on the detection results of the HC concentration detection means and the intake differential pressure detection means, the evaporated fuel amount calculation means calculates the fuel amount of the fuel evaporative gas sucked into the intake system of the engine, and the evaporated fuel Since the fuel correction unit corrects the fuel injection amount by the fuel control unit based on the calculation result of the amount calculation unit, the fuel amount of the fuel evaporative emission gas can be reliably calculated in the entire operation range. According to a second aspect of the present invention, the HC concentration detecting means detects the concentration of the fuel evaporative gas sucked into the intake system of the engine in which the surge tank is arranged on the downstream side from the adsorbing means for adsorbing the fuel evaporative gas, and the intake system of the engine is detected. The differential pressure between the adsorbing means and the adsorbing means is detected by the intake differential pressure detecting means, and based on the detection results of the HC concentration detecting means and the intake differential pressure detecting means, the evaporated fuel amount calculating means detects the amount of the fuel evaporated gas sucked into the intake system of the engine. The fuel amount is calculated, and the fuel amount calculated by the evaporated fuel amount calculation means is corrected by the evaporated fuel amount correction calculation means in accordance with the delay time until the fuel evaporated gas is sucked into the combustion chamber of the engine through the flow passage. Then, the fuel correction means corrects the fuel injection quantity by the fuel control means based on the calculation result of the evaporated fuel quantity correction calculation means, so that the fuel quantity of the fuel evaporated gas can be calculated more reliably in the entire operating range.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The engine fuel control system of FIG. 1 is installed in a 4-cycle gasoline engine (hereinafter simply referred to as engine) 1. Here, the engine 1 is provided with a plurality of cylinders (only the # 1 cylinder is shown in FIG. 1) in series in its main body. The intake passage 3 extending from the cylinder head 2 at the upper part of the main body of the engine 1 is connected to a surge tank 5 via an intake manifold 4.
Inside, they are joined to the intake passages of other cylinders. On the other hand, the exhaust passage 6 extending from the cylinder head 2 reaches a muffler (not shown) via an exhaust manifold 7 and an exhaust pipe (not shown). A fuel injection valve 30 (only the valve of the # 1 cylinder is shown in FIG. 1) for supplying fuel to each cylinder is arranged at each cylinder facing portion of the intake manifold 4, and each fuel injection valve 30 has a branch fuel. The fuel pipe 32 is connected to the fuel pipe 32 via a pipe 31, and its opening / closing control is executed by an engine control unit (hereinafter simply referred to as ECU) 13 which will be described later.

The fuel pipe 32 extends from the fuel pump 33 in the fuel tank 19 and reaches the fuel pressure regulator 34. The low pressure pipe 35 extending from the fuel pressure regulator 34 is connected to the fuel tank 19.
Is configured to return to. Here, the fuel pressure regulator 3
4 receives a boost pressure to perform a pressure adjusting operation, and when the boost pressure is reduced, the pressure in the fuel pipe 32 is reduced, and when the boost pressure approaches atmospheric pressure, the fuel pressure is increased. Reference numeral 36 indicates a fuel filter. Intake passage 3
The upstream side opening of the surge tank 5 on the side communicates with the throttle body 8, and the throttle body 8 communicates with the air cleaner 10 via an intake pipe. The throttle body 8 has a throttle valve 9 therein, and the throttle opening sensor 1 for outputting a throttle opening signal θs to the valve 9.
1 is provided. The surge tank 5 is equipped with an intake pressure sensor 18 for detecting an intake pressure Pa, which is one of the operating states of the engine, in its inner wall.

The throttle body 8 is provided with a well-known fast idle air valve 12 and an ISC valve 14 controlled by the ECU 13, both valves adjusting the air flow rate of the bypass passage 15 bypassing the throttle valve 9,
It is configured to control idle rotation. Moreover, the throttle valve 9 is provided on the inner wall of the intake passage 3 of the throttle body 8.
An inflow port 17 of the purge flow path 16 is formed at a position opposite to, and the fuel evaporative gas is introduced from the inflow port 17 into the intake path 3. The purge channel 16 is a fuel tank 19
It is connected to a canister 20 as an adsorbing means for adsorbing the fuel evaporative gas generated from the. The canister 20 is supplied with the fuel evaporative gas through a purge gas pipe 21 opening in the upper space of the fuel tank 19, and can adsorb the fuel component to the fuel adsorbent 201 when the fuel evaporative gas is introduced toward the atmosphere opening port 22 side. . Reference numeral 23 is a check valve, and this valve blocks the reverse flow of the fuel evaporative gas in the purge gas pipe 21. The purge channel 16 has a canister 20.
A pressure sensor 24 capable of outputting the internal pressure Pc, an HC concentration sensor 25 serving as an HC concentration detecting means arranged downstream of the pressure sensor for outputting a concentration signal of the fuel evaporative emission gas, and a solenoid valve for opening and closing the purge passage 16. 26 and 26 are provided in this order.

The HC concentration sensor 25, as shown in FIG.
The first resistor r1 exposed on the air intake passage facing surface 252 of the sensor substrate 251 and the second resistor r2 sealed in the case 253.
Both of these resistors are connected to a pair of fixed resistors r3 and r4 as shown in FIG. 5 to form a bridge circuit 26. In this bridge circuit 26, a power source 27 is connected between a connection point j1 of the first resistor r1 and the fixed resistor r3 and a connection point j2 of the second resistor r2 and the fixed resistor r4, and the first resistor r1 and the second resistor r1 are connected. Connection point j3 of resistor r2 and both fixed resistors r3
A configuration is adopted in which the voltage Vs with respect to the connection point j4 of r4 is output.
Here, when the fuel evaporative gas flows compared with the case where air flows in the purge flow path 16, the higher the HC concentration of the fuel evaporative gas is, the more the cooling of the first resistor r1 is promoted, and the resistance value is increased. On the other hand, the second resistance r2 does not come into contact with the fuel evaporative gas in the purge channel 16 and changes the resistance value only by the channel temperature. Therefore, the amount of change in the partial pressure value of the first and second resistors r1 and r2 is the same as that of the fuel evaporative gas after canceling the temperature change.
It can be regarded as a value V _HC corresponding to the concentration. Here, the HC concentration signal Vs output from the bridge circuit 26 is output to the ECU 13 via an A / D converter (not shown) and used as HC concentration information.

The main part of the ECU 13 is composed of a microcomputer, and the ROM (not shown) is provided with a microcomputer shown in FIG.
0, the control program as shown in FIG. 11, the engine operating range determination map of FIG. 6, the intake efficiency correction value Ken calculation map of FIG. 7, the purge operating range map of FIG. 8 and the values of each data are stored. A CPU (not shown) of the ECU 13 calculates a control amount according to each operation information according to each control program and a map, and drives the solenoid valve 26, the fuel injection valve 30 and the like by the same value. In addition to the throttle opening sensor 11 and the intake pressure sensor 18 as described above, an input / output circuit (not shown) outputs a pressure sensor 24, an HC concentration sensor 25, a water temperature sensor 29 that outputs water temperature WT information, and intake air temperature Ta information. An intake air temperature sensor 37, a crank angle sensor 36 that outputs a unit crank angle signal Δθ which is an engine speed Ne signal, and the like are connected, and each detection signal is taken in from these at a proper time. Moreover, the solenoid valve 26 and the fuel injection valve 30 are connected. Is configured to emit a drive output in a timely manner.

Particularly, here, the ECU 13 controls the intake pipe pressure P by the intake pressure sensor 18 which is operation information as shown in FIG.
b, fuel control means A for controlling the fuel injection amount Q based on each output of the engine speed Ne by the crank angle sensor 36
1, and evaporative fuel amount calculation means A2 for calculating the fuel amount of the fuel evaporative gas sucked into the intake passage 3 through the purge passage 16 based on the detection results of the HC concentration sensor 25, the intake pressure sensor 18, and the pressure sensor 24. Evaporative fuel amount correction in which the fuel amount calculated by the evaporated fuel amount calculating means A2 is corrected and calculated in accordance with the delay time until the fuel evaporated gas is sucked into the combustion chamber of the engine 1 through the purge passage 16. The calculation unit A3 and a function as a fuel correction unit A4 that corrects the fuel injection amount by the fuel control unit A1 based on the calculation result of the evaporated fuel amount correction calculation unit A3 are provided. In the fuel supply control here, the basic fuel pulse width Tf based on the intake air amount
Is calculated, and this is multiplied by an air-fuel ratio and other correction factors to determine the injector drive time, and during cylinder deactivation (injector stop command described below), cylinders # 2, which are always operating except cylinder deactivated cylinders # 1, # 4. A well-known injector drive control process of driving the injectors 25 of only # 3 and driving the injectors 25 of all the cylinders when all cylinders are in operation is performed. Figure 10
11 to 11 show respective flowcharts of the control program of the ECU 13 used in the fuel control apparatus for the engine as one embodiment of the present invention.

The ECU 13 enters control in a main routine by turning on a key of a main switch (not shown). Here, first, after checking each sensor function and setting an initial function set such as an initial value set, the process reaches step a1.
From the throttle opening sensor 11, the intake pressure sensor 18, the pressure sensor 24, the HC concentration sensor 25, the water temperature sensor 29, the intake temperature sensor 37, the crank angle sensor 36, etc., the throttle opening θs signal, the intake pressure Pb signal, the canister internal pressure Pc, HC concentration V _HC signal, water temperature WT signal, intake air temperature Ta
The signal, the unit crank angle signal Δθ that becomes the engine speed Ne signal is taken in. In step a2, the intake air amount A / N is calculated based on the intake air state equation (P · V = N · R · Ta).
Is calculated by the following formula (1) and stored in a predetermined area. Note that P is the pressure in the cylinder at bottom dead center, V is the cylinder volume, N is the number of moles of air, R is the gas constant, and Ta intake air temperature. The cylinder pressure P at the inner bottom dead center is the intake pipe pressure Pb.
Is corrected by the inhalation efficiency correction value Ken, and P (= Pb × Ke
n) is calculated. The inhalation efficiency correction value Ken is set by the inhalation efficiency correction value Ken calculation map, and an example of the map is shown in FIG. 7.

P × 1/760 × V → A / N ... (1) After this, the engine speed Ne and A / N as load information
The fuel cut zone is determined from an operation range map (one example of which is shown in FIG. 6) for calculating the operation range. In the fuel cut range, the process proceeds to step a4, and the air-fuel ratio feedback FLG
Is cleared, the fuel cut FLG is set to 1, and step a1 is performed.
Go to 2. On the other hand, if it is determined that the fuel cut range is not reached in step a3 and the process reaches step a6, the fuel cut FLG is cleared, and subsequently it is determined in step a7 whether or not the air-fuel ratio feedback condition is satisfied. Here, at the time of a transitional operation range such as the power operation range or before the completion of warming up, the process proceeds to step a8 to calculate the air-fuel ratio correction coefficient KMAP according to the current operation information (A / N, Ne). Value is stored in the address K _AF , and the process proceeds to step a12.

When the air-fuel ratio feedback condition is satisfied from step a7, the routine proceeds to step a9, where the target air-fuel ratio A / F according to the current operation information (A / N, Ne) is set,
A fuel amount correction coefficient K _FB that can achieve the same air-fuel ratio is calculated.
At step a10, the fuel amount correction coefficient K _{FB is} added to the address K _AF.
Is stored, and step a11 is reached. Here, the other fuel injection pulse width correction coefficient KDT and the correction value TD of the dead time of the fuel injection valve are used as the water temperature WT signal and the intake air temperature T.
It is set according to the operating conditions such as signal a, and the process proceeds to step a12. When step a12 is reached, it is determined here based on the engine speed Ne and the intake air amount A / N whether or not the current operation range is the purge operation range along the purge operation range determination map m3, and the purge prohibition range is left as it is. During this time, the fuel evaporative gas generated in the fuel tank 19 flows into the canister 20 through the purge gas pipe 21 and the check valve 23 and is adsorbed. On the other hand, in the purge operation area, the process proceeds to step a13. In the determination as to whether it is in the purge operation range, the determination value is E1 = f (Ne) as shown in FIG. 8 when the previous time is the purge operation range, and the determination value is E1 when the last time is the purge prohibition range. It is possible to prevent hunting at the time of area switching by setting E2 = f '(Ne) which is set larger.

In steps a13 and a14, it is assumed that the purge operation range is set, the post-purge timer TIM1 is updated to start counting the purge operation time, and the purge solenoid valve 26 is opened to lean. As a result, the fuel evaporative gas absorbed by the canister 20 passes through the opened solenoid valve 26 and flows into the intake passage 3 from the inflow port 17,
The purge operation is started. An interrupt is made for each predetermined crank angle in the middle of the main routine, and the fuel injection control routine is started when the TDC signal of the first cylinder is input as shown at time t1 in FIG. In this fuel injection control routine, the HC concentration signal Vc, the intake pressure Pa, and the canister internal pressure Pc are fetched in step s1. Going to step s2,
Here, it is determined whether or not the count value of the timer TIM1 after the start of purging has passed the preset purge time Tα for one time. Before the lapse of time, when step s3 has passed, the process proceeds to step s11, and the fuel correction amount T _P To zero,
Go to step s6.

When step s3 is reached, the purge fuel amount f
_P (g / sec) is calculated by the equations (2) and (3).

Gp = K × A × √ (Pc−Pm) (2) f _P = Gp × Cp (3) where Gp is the gas flow rate (l / Sec), Cp uses the HC concentration signal V _HC of the HC concentration sensor 25, A is the equivalent squeeze cross-sectional area of the pipe, Pc is the canister internal pressure of the pressure sensor 24, and P _M is the engine manifold pressure and intake pressure. The intake pressure Pa of the sensor 18 is used, and K is a constant. The purged fuel amount fp thus calculated proceeds to step s4, and the delay time until the intake system fuel vaporized gas is sucked into the combustion chamber of the engine 1 through the purge flow path 16 by the formula (4) is taken into consideration. The amount of purged fuel per stroke is calculated.

[0020]

[Equation 1]

Here, γ is appropriately set as a filtering coefficient of 0 <γ <1, and f _P (i) is the current f
_PN (i-1) shows the amount of each purge fuel of the last time, and Nc shows the number of cylinders of the engine 1. The purge fuel amount f _PN thus calculated is the injector gain − in step s5.
Multiplied by G _I and purged fuel correction amount T _P (= −G _I ×
f _PN ) is required.

Further, when step s6 is reached, information on whether or not the fuel is cut is sought here, and when the fuel cut is returned,
Otherwise, the process proceeds to steps s7 and s8. Here, the basic fuel pulse width Tf is calculated from the intake air amount A / N according to the equation (5), and then the fuel pulse width Tinj is obtained from the equation (6). Here, G _I is an injector gain, K _AF is an air-fuel ratio correction coefficient taken from the main routine side, KDT is an atmospheric temperature and atmospheric pressure correction coefficient, and TD is an injector operation delay correction value TD. _{Tf = G I × A / N} × K AF × 1 / 14.7 ······ (5) Tinj = Tf × KDT + T P ········ (6) Thereafter, in step s9 total The target fuel pulse width Tinj is set in a driver (not shown) for driving the fuel injection valve 30 of the cylinder. Then, each driver is triggered and the process returns.

As a result, the driver for driving each cylinder counts the unit crank angle, and when the crank angle corresponding to each injection timing is reached (see FIG. 9), each fuel injection valve 30 is sequentially driven to perform fuel injection. . Fuel injection amount at this time (T
The amount corresponding to inj) is calculated by excluding the purge fuel correction amount T _P (= −G _I × f _PN ) from the basic fuel amount (the amount corresponding to Tf). The purge fuel amount f _PN from 17 is added to supply fuel to each cylinder. Therefore, even if the purge fuel flows into the intake passage 3,
Target air-fuel ratio (adjusted by air-fuel ratio correction coefficient K _AF )
Fuel can be supplied without shifting the engine, and the engine can be driven without reducing drivability and fuel consumption. In the above description, when the purged fuel amount fp is calculated, the formula (4) is used to calculate the delay time until the intake system fuel vapor is sucked into the combustion chamber of the engine 1 through the purge passage 16. Although the amount of purged fuel per stroke is calculated in consideration, the configuration shown in FIG. 3 may be adopted instead.

When the second embodiment is compared with the first embodiment of FIG. 1, the function of the ECU 13 is different from that of the constituent member of FIG. 1 in that the surge tank 5 is eliminated and the intake passage 3 is shortened. The other configurations are the same, and the duplicate description will be omitted here. As shown in FIG. 3, the ECU 13 'in the second embodiment uses the intake pressure sensor 18 which is the operation information.
The fuel control means A1 for controlling the fuel injection amount Q based on the output of the intake pipe pressure Pb by the crank angle sensor 36 and the engine speed Ne by the crank angle sensor 36, and the detection results of the HC concentration sensor 25, the intake pressure sensor 18, and the pressure sensor 24. Based on the calculation result of the evaporated fuel amount calculation means A2 for calculating the fuel amount of the fuel evaporative gas sucked into the intake passage 3 through the purge flow path 16 and the fuel injection amount by the fuel control means A1 based on the calculation result of the evaporated fuel amount calculation means A2 It has a function as a fuel correction unit A4 for correcting.

In this case, there is no surge tank, and the intake passage 3
The distance between the inlet 17 of the engine and the combustion chamber of the engine is relatively short,
There is no need to consider the delay time. Therefore, in the fuel injection control routine, directly from step s3 to step s
5, the purge fuel correction amount T _P (= −G _I × f) is calculated using the purge fuel amount fp calculated by the equations (2) and (3).
_PN ) is calculated. In this case, the control can be simplified.

[0026]

As described above, the present invention detects the concentration of fuel evaporative gas and the differential pressure between the intake system of the engine and the adsorbing means, and based on these detection results, the fuel evaporative gas drawn into the intake system is detected. The fuel injection amount is calculated based on the calculated fuel amount and the fuel injection amount is corrected based on the calculated result. Therefore, the fuel amount of the fuel evaporative gas can be reliably calculated in the entire operating range, and the fuel is supplied without shifting the target air-fuel ratio The engine can be driven without deteriorating the ability and fuel efficiency. The second invention is
When calculating the fuel amount of the fuel evaporative gas sucked into the intake system of the engine, it is calculated by correcting the delay time until the fuel evaporative gas is sucked into the combustion chamber of the engine through the flow path. Since the fuel injection amount is corrected based on the calculation result, it is possible to more reliably calculate the fuel amount of the fuel evaporative gas over the entire operating range, and the fuel is supplied without shifting the target air-fuel ratio, which improves drivability and fuel efficiency. Without lowering
Can drive the engine.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a fuel control device for an engine as an embodiment of the present invention.

FIG. 2 is a functional block diagram of the fuel control device of FIG.

FIG. 3 is a functional block diagram of a fuel control device for an engine as another embodiment of the present invention.

FIG. 4 is a schematic perspective view of an HC concentration sensor used in the fuel control device of FIG.

5 is a circuit diagram to which the HC concentration sensor of FIG. 4 is connected.

FIG. 6 is a characteristic diagram of an operating range determination map used in the fuel control device of FIG.

FIG. 7 is a characteristic diagram of an intake efficiency correction value calculation map used in the fuel control device of FIG.

8 is a characteristic diagram of a purge operation range determination map used in the fuel control system of FIG.

9 is an explanatory view of fuel injection timing of an engine equipped with the fuel control device of FIG.

FIG. 10 is a flowchart of a main routine executed by the ECU of the fuel control device in FIG.

11 is a flowchart of a fuel injection control routine executed by an ECU of the fuel control device in FIG.

[Explanation of symbols]

1 Engine 3 Intake Path 5 Surge Tank 9 Throttle Valve 11 Throttle Opening Sensor 13 ECU 16 Canister Flow Path 17 Inlet 18 Intake Pressure Sensor 19 Fuel Tank 20 Canister 24 Pressure Sensor 25 HC Concentration Sensor 36 Engine Rotation Sensor Tinj Fuel Injection A1 Fuel control means A2 Evaporated fuel amount calculation means A3 Evaporated fuel amount correction calculation means A4 Fuel correction means Pc Canister internal pressure Pa Intake pressure f _PN Purge fuel amount θs Throttle opening signal Ne Engine speed signal

Claims (2)

[Claims] 1. A means for detecting an operating state of an engine, a fuel control means for controlling a fuel injection amount based on an output of the detecting means, an adsorbing means for adsorbing a fuel evaporative gas generated from a fuel tank, and the adsorbing means. Means for communicating the means with the intake system of the engine, an HC concentration detecting means provided in the passage for detecting the concentration of the fuel evaporative gas sucked into the intake system of the engine from the adsorption means, and the passage. The intake air differential pressure detecting means for detecting the differential pressure between the intake system of the engine and the adsorbing means, and the engine through the flow path based on the detection results of the HC concentration detecting means and the intake differential pressure detecting means. Fuel vapor amount calculation means for calculating the fuel amount of the fuel vaporized gas sucked into the intake system, and a fuel amount correction means for correcting the fuel injection amount by the fuel control means based on the calculation result of the vaporized fuel amount calculation means. Fuel control apparatus for an engine, characterized by comprising a correction means. 2. A means for detecting an operating state of an engine, a fuel control means for controlling a fuel injection amount based on an output of the detection means, an adsorbing means for adsorbing a fuel evaporative gas generated from a fuel tank, and the adsorbing means. Means for communicating the means with the intake system of the engine, an HC concentration detecting means provided in the passage for detecting the concentration of the fuel evaporative gas sucked into the intake system of the engine from the adsorption means, and the passage. The intake air differential pressure detecting means for detecting the differential pressure between the intake system of the engine and the adsorbing means, and the engine through the flow path based on the detection results of the HC concentration detecting means and the intake differential pressure detecting means. The fuel vapor amount calculation means for calculating the fuel amount of the fuel vaporized gas sucked into the intake system, the surge tank arranged on the downstream side of the intake system where the flow path opens, and the fuel vapor amount calculation means An evaporated fuel amount correction calculation means for correcting the calculated fuel amount in accordance with a delay time until the fuel evaporated gas is sucked into the combustion chamber of the engine through the flow path, and the evaporated fuel. A fuel control device for an engine, comprising: a fuel correction unit that corrects a fuel injection amount by the fuel control unit based on a calculation result of the amount correction calculation unit.