JP6477508B2 - Fuel injection amount control device for internal combustion engine - Google Patents

Description

  The present invention is applied to an internal combustion engine that can use fuel containing alcohol, and the fuel injection amount of the internal combustion engine that determines the fuel injection amount according to the fuel attachment amount that is the amount of fuel that adheres to the members constituting the intake passage. The present invention relates to a control device.

  Conventionally, the amount of fuel adhering to and remaining in the members constituting the intake passage such as the intake manifold and the intake port (that is, the amount of fuel adhering) is estimated using a fuel behavior model, and according to the estimated amount of adhering fuel. A fuel injection amount control device that increases or decreases the fuel injection amount is known (see, for example, Patent Document 1).

JP 2004-353477 A

  By the way, the fuel adhesion amount varies depending on the “temperature of the member constituting the intake pipe” expressed by the cooling water temperature, the “pressure in the intake pipe” expressed by the engine load, the engine rotation speed, and the like. For example, FIG. 6 is a graph showing “relationship between load and fuel adhesion amount” at a specific engine rotation speed for each cooling water temperature. The control device stores “relationship between load and fuel adhesion amount” represented by such a graph in a lookup table (map) format for a plurality of engine speeds.

  On the other hand, gasoline includes light gasoline with high volatility and heavy gasoline with low volatility. Therefore, the fuel adhesion amount also changes depending on the ratio of “light gasoline and heavy gasoline” contained in the fuel. However, it is difficult to determine the actual volatility of the refueled gasoline (that is, the gasoline property as to whether it is light or heavy). Accordingly, the map as shown in FIG. 6 is created assuming typical gasoline at the destination of the vehicle, and the difference in volatility between the actually refueled gasoline and typical gasoline is This is done by correcting the cooling water temperature applied to the map.

  More specifically, when the load of the engine increases and the fuel adhesion amount increases, if it is estimated that the increase amount of the fuel adhesion amount is smaller than the actual amount, the fuel injection amount is insufficient and the internal combustion engine The acceleration performance of the engine deteriorates. To avoid this, when the engine load increases and the amount of fuel deposited increases, it is generally assumed that the gasoline being used is heavier than typical gasoline and the cooling applied to the map The water temperature is set to a temperature lower than the actual cooling water temperature. Hereinafter, the coolant temperature applied to the map is referred to as “map-applied coolant temperature”. For example, when the load shown in FIG. 6 is used to increase the load from 30% to 60%, the map-applied cooling water temperature when the current cooling water temperature is the intermediate water temperature is “a lower value than the intermediate water temperature. Set to "Water temperature". Therefore, it is estimated that the fuel adhesion amount has increased by the increase amount D1 from the fuel adhesion amount at the point P1 to the fuel adhesion amount at the point P2.

  On the other hand, when the load on the engine decreases and the amount of fuel adhering decreases, if the amount of fuel adhering decrease is estimated to be larger than the actual amount, the adhering fuel enters the cylinder The amount of fuel is estimated to be larger than the amount of fuel that actually enters the cylinder, and the fuel is injected after the amount of fuel is subtracted from the basic fuel injection amount. Therefore, the fuel is excessively reduced, and the air-fuel mixture becomes thin. This can lead to misfire. To avoid this, when the engine load decreases and the fuel deposit decreases, it is generally assumed that the gasoline used is lighter than typical gasoline, and the map-applied cooling water temperature is actually It is set to a temperature higher than the cooling water temperature. For example, when the load shown in FIG. 6 is used to reduce the load from 60% to 30%, the map-applied cooling water temperature when the current cooling water temperature is the intermediate water temperature is “higher than the intermediate water temperature. Set to "Water temperature". Therefore, it is estimated that the fuel adhesion amount has decreased by the reduction amount D2 from the fuel adhesion amount at the point P3 to the fuel adhesion amount at the point P4. As is clear from FIG. 6, the increase amount D1 is larger than the decrease amount D2.

  However, when the amount of change in the fuel adhesion amount is estimated and the correction amount for the basic fuel injection amount (that is, the fuel adhesion correction amount) is determined in this way, the fuel adhesion correction amount gradually increases as described in detail below. In the case where the fuel injection amount should be corrected to decrease, there is a problem that the fuel injection amount cannot be corrected to decrease. In this specification and the like, “current value X” means the latest value X (current value of value X) obtained at the present time, and “previous value of value X” is a predetermined time ( For example, it means a value X obtained at a point in time before the crank angle is rotated by 90 ° or a predetermined time.

The fuel adhesion correction amount fmw is obtained based on the following equation (A1).

fmw = dlqmw / kmw1 + qtrnold / kmw2 (A1)

The first term (dlqmw · kmw1) on the right side of the equation (A1) is an immediate correction term.
dlqmw is “the amount of change in the amount of fuel adhering before and after the engine load KL changes” given by the following equation (A2).
kmw1 is a coefficient that varies depending on the coolant temperature THW, the load KL, the engine speed NE, and the like.

dlqmw = qmwanow−qmwaold (A2)

The first term qmwanow on the right side of the equation (A2) is obtained by applying “map applied cooling water temperature thwmap, current load KL and current engine speed NE” to the map described above. This is the value.
The second term qmwaold on the right side of the equation (A2) is the previous value of qmwanow (that is, the previous value of the estimated value of the fuel adhesion amount).

The second term (qtrnold · kmw2) on the right side of the equation (A1) is a tailing term.
qtrnold is the previous value of the transient correction amount qtrn given by the following equation (A3).
kmw2 is a coefficient that varies depending on the coolant temperature THW, the load KL, the engine speed NE, and the like.

qtrn = dlqmw · (1-kmw1) + qtrnold · (1-kmw2) (A3)

  As understood from the equations (A1) to (A3) above, when it is estimated that the fuel adhesion amount has changed by the change amount dlqmw due to the change in the load KL, the “change amount” is used as an immediate correction term. The fuel injection amount is corrected by the value of the coefficient dlqmw multiplied by 1 kmw. On the other hand, a value (1-kmw1) times the amount of change dlqmw, that is, the amount dlqmw · (1-kmw1) not used for correcting the fuel injection amount as an immediate correction term is accumulated in the transient correction amount qtrn. . Then, the amount of fuel adhering is calculated by assuming that the accumulated amount is released by kmw2 every elapse of a predetermined time. This discharge amount is a tailing term (qtrnold · kmw2), and qtrnold · (1−kmw2) is calculated as an accumulated amount remaining as a tailing correction.

  By the way, when the map-applied cooling water temperature is determined as described above, the load KL increases from the first load (for example, 30%) to the second load (for example, 60%) by a predetermined load change amount, and the fuel adhesion amount is increased. The amount of fuel adhering amount change dlqmw estimated when it increases (the amount corresponding to D1) decreases by the same predetermined load changing amount from the second load to the first load. It becomes larger than the amount of change dlqmw of the fuel adhesion amount estimated when the amount decreases (amount corresponding to the above D2).

  As a result, if the increase and decrease of the load KL are repeated within a short time (that is, before the transient correction amount qtrn is attenuated and becomes sufficiently small), the transient correction amount can be understood from the above equation (A3). qtrn gradually accumulates and becomes excessive. As a result, even when the load KL decreases and the basic fuel injection amount needs to be reduced, the fuel adhesion correction amount fmw becomes a positive value (that is, a value that increases the fuel injection amount), and the fuel injection There is a problem that the amount becomes excessive.

  On the other hand, recently, a vehicle (FFV: Flexible Fuel Vehicle) on which an internal combustion engine capable of using an alcohol-containing fuel (a gasoline fuel having an alcohol concentration higher than 0%) has been developed. The alcohol concentration of the alcohol-containing fuel also affects the fuel volatility. Therefore, the fuel adhesion amount varies depending not only on whether the gasoline contained in the alcohol-containing fuel is heavy or light, but also on the alcohol concentration of the alcohol-containing fuel.

)
Therefore, in the FFV, the “map for estimating the fuel adhesion amount” used when obtaining the fuel adhesion correction amount shows the relationship between the load, the engine rotational speed, the coolant temperature and the alcohol concentration of the fuel, and the fuel adhesion amount. Is created and stored in the storage unit of the control device.

  FIG. 7 is a graph showing “relationship between load and fuel adhesion amount” for each alcohol concentration (actually ethanol concentration) when the coolant temperature is a predetermined temperature and the engine rotational speed is a predetermined rotational speed. It can be considered that the control device stores a map defining “relation between load and fuel adhesion amount” as shown in this graph for each combination of the coolant temperature and the engine speed. When the load changes, a map that defines the “relationship between load and fuel adhesion amount” is selected according to the coolant temperature and the engine speed, and the load before and after the change is applied to the map. Thus, the fuel adhesion amount before the load change and the fuel adhesion amount after the load change are obtained, and the change amount of the fuel adhesion amount (accordingly, the fuel adhesion correction amount) is obtained from them.

  By the way, the alcohol concentration of the alcohol-containing fuel is acquired (estimated) based on an alcohol concentration sensor or a feedback correction amount in the air-fuel ratio feedback control. However, in any case, the acquired alcohol concentration does not completely match the true alcohol concentration, and has an error with respect to the true alcohol concentration. Therefore, it is necessary to obtain the amount of change in the fuel adhesion amount (and hence the fuel adhesion correction amount) in consideration of the error.

  More specifically, when the load of the engine increases and the fuel adhesion amount increases, if it is estimated that the increase amount of the fuel adhesion amount is smaller than the actual amount, the fuel injection amount is insufficient and the internal combustion engine The acceleration performance of the engine deteriorates. In order to avoid this, when the load of the engine increases and the fuel adhesion amount increases, it is generally assumed that the actual alcohol concentration is higher than the “acquired (estimated) alcohol concentration”. That is, the alcohol concentration applied to the map is set to “a concentration higher than the acquired (estimated) alcohol concentration”. Hereinafter, the alcohol concentration applied to the map is referred to as “map applied concentration”.

  For example, to explain using the map shown in FIG. 7, when the load increases from 40% to 60%, the map application concentration is “higher than 70%” when the acquired alcohol concentration is 70%. Density (for example, 100%) ”. Therefore, it is estimated that the fuel adhesion amount has increased by the increase amount D3 from the fuel adhesion amount at the point P5 to the fuel adhesion amount at the point P6.

  On the other hand, when the load on the engine decreases and the amount of fuel adhering decreases, if the amount of fuel adhering decrease is estimated to be larger than the actual amount, the adhering fuel enters the cylinder The amount of fuel is estimated to be larger than the amount of fuel that actually enters the cylinder, and the fuel is injected after the amount of fuel is subtracted from the basic fuel injection amount. Therefore, the fuel is excessively reduced, and the air-fuel mixture becomes thin. This can lead to misfire. In order to avoid this, it is generally assumed that the actual alcohol concentration is lower than the “acquired (estimated) alcohol concentration” when the load on the engine is reduced and the fuel adhesion amount is reduced. That is, the map application concentration is set to “a concentration lower than the acquired (estimated) alcohol concentration”.

  For example, when the load on the engine is reduced and the fuel adhesion amount is reduced, if the alcohol concentration acquired (estimated) is 70%, the map application concentration is “a concentration lower than 70% (for example, 22%). "Is set. Therefore, for example, when the load decreases from 60% to 40%, it is estimated that the fuel adhesion amount is decreased by the decrease amount D4 from the fuel adhesion amount at the point P7 to the fuel adhesion amount at the point P8. As is clear from FIG. 7, the increase amount D3 is larger than the decrease amount D4.

  As a result, as in the case of using the map-applied cooling water temperature described above, when the increase and decrease of the load KL are repeated within a short time, the transient correction amount qtrn is gradually accumulated as understood from the equation (A3). As a result, even if the load decreases and the basic fuel injection amount needs to be reduced, the fuel adhesion correction amount becomes a positive value (that is, a value that increases the fuel injection amount), and the fuel There is a problem that the injection amount becomes excessive.

  The present invention has been made to address the above problems. That is, one of the objects of the present invention is to provide a “fuel injection amount control device for an internal combustion engine” that can appropriately correct the fuel injection amount to compensate for the change in the fuel adhesion amount in the internal combustion engine of the FFV vehicle. It is to provide.

An internal combustion engine fuel injection amount control apparatus (hereinafter also referred to as “the present invention apparatus”) according to the present invention.
A fuel injection valve (39) for injecting fuel containing alcohol into the intake passage of the internal combustion engine (10);
Relationship between the load of the engine, the rotational speed of the engine, the temperature of the cooling water of the engine, and the alcohol concentration of the fuel, and the amount of fuel adhering to the member constituting the intake passage Storage means (ROM 72) for storing (MAPqmw (KL, THW, Eth, NE));
The actual load that is the actual load of the internal combustion engine, the actual engine rotation speed that is the actual rotation speed of the engine, the actual cooling water temperature that is the actual cooling water temperature of the internal combustion engine, and the actual alcohol concentration of the fuel Parameter acquisition means (step 305) for repeatedly acquiring a certain actual alcohol concentration;
The latest value of the actual load, the latest value of the actual engine rotational speed, the value according to the latest value of the actual cooling water temperature, and the value according to the latest value of the actual alcohol concentration are applied to the relationship to apply the fuel adhesion. Correction amount calculation means (step 345, step 355) for calculating a fuel adhesion correction amount according to the amount of change,
A basic fuel injection amount for obtaining an air-fuel ratio of an air-fuel mixture supplied to the engine based on at least the actual load to a predetermined target air-fuel ratio is acquired and the basic fuel injection amount is corrected by the fuel adhesion correction amount. Injection amount control means (steps 375 and 380) for injecting the fuel injection amount of the fuel obtained from the fuel injection valve;
Is provided.

  Further, the correction amount calculation means includes an increase correction amount calculation means and a decrease correction amount calculation means.

The increasing correction amount calculating means includes
Based on the latest value of the actual cooling water temperature and the latest value of the alcohol concentration, a water temperature offset amount for increasing is acquired (step 315),
An increase cooling water temperature is calculated by changing the latest value of the actual cooling water temperature by the increase water temperature offset amount (step 335),
Acquiring a concentration offset amount for increasing based on the latest value of the actual cooling water temperature and the latest value of the alcohol concentration (step 325);
An increasing alcohol concentration is calculated by changing the latest value of the actual alcohol concentration by the increasing concentration offset amount (step 335);
By applying the increase coolant temperature, the increase alcohol concentration, the latest value of the actual load, and the latest value of the actual engine rotation speed to the relationship, the fuel increase amount for the current increase is estimated. (Step 345),
Based on the difference between the current increase fuel adhesion amount and the previous increase fuel adhesion amount, which is the increase fuel adhesion amount estimated at a predetermined time before, the fuel adhesion correction amount candidates A correction amount for increase is calculated (step 345).

On the other hand, the correction amount calculation means for reducing the weight is
Obtaining a water temperature offset amount for weight reduction based on the latest value of the actual cooling water temperature and the latest value of the alcohol concentration (step 320);
The cooling water temperature for weight reduction is calculated by changing the latest value of the actual cooling water temperature by the offset water temperature offset amount (step 335),
Acquiring a concentration offset amount for weight reduction based on the latest value of the actual cooling water temperature and the latest value of the alcohol concentration (step 330);
Calculating the alcohol concentration for weight reduction by changing the latest value of the actual alcohol concentration by the concentration offset amount for weight reduction (step 335);
By applying the weight-reducing cooling water temperature, the weight-reducing alcohol concentration, the latest value of the actual load, and the latest value of the actual engine rotational speed to the relationship, the current weight-reducing fuel adhesion amount is estimated. (Step 355),
Based on the difference between the current amount of fuel attachment for weight reduction and the previous amount of fuel attachment for weight reduction that was estimated at the time before the predetermined time, the fuel adhesion correction amount A reduction amount for correction as a candidate is calculated (step 355).

The injection amount control means
One of the increase correction amount and the decrease correction amount is adopted as the fuel adhesion correction amount (steps 360 to 370).

Furthermore, in one aspect of the apparatus of the present invention, the injection amount control means includes:
When the increase correction amount is a value that increases the basic fuel injection amount, the increase correction amount is adopted as the fuel adhesion correction amount (steps 360 and 365).
When the increase correction amount is a value that does not increase the basic fuel injection amount, the decrease correction amount is adopted as the fuel adhesion correction amount (steps 360 and 370).

More specifically,
The increasing correction amount calculating means includes
The difference between the current increase fuel adhesion amount (qmwanow) and the previous increase fuel adhesion amount (qmwaold) is calculated as the current increase adhesion amount (dlqmwz),
The immediate correction remainder (dlqmwz · (1-kmw1)) corresponding to the first predetermined ratio (1-kmw1) of the current adhesion increase amount (dlqmwz), and the value before the predetermined time of the transient correction amount for increase The sum of the tailing correction residual qtrnzold · (1-kmw2) corresponding to a second predetermined ratio (1-kmw2) of a certain previous increase transient correction amount (qtrnzold) and the current increase transient correction amount (qtrnz) As
The amount (dlqmwz · kmw1) obtained by subtracting the immediate correction residual (dlqmwz · (1-kmw1)) from the current adhesion increase amount (dlqmwz) and the tailing correction from the previous transient increase correction amount (qtrnzold). The sum of the amount obtained by subtracting the remainder (qtrnzold · (1−kmw2)) (qtrnzold · kmw2) and the correction amount for increase is calculated.
Configured as follows.

The weight reduction correction amount calculation means includes:
The difference between the current weight loss fuel adhesion amount (qmwbnow) and the previous weight loss fuel adhesion amount (qmwbold) is calculated as the current adhesion increase amount (dlqmwg),
The immediate correction remainder (dlqmwg · (1-kmw3)) corresponding to the third predetermined ratio (1-kmw3) of the current adhesion increase amount (dlqmwg) and the value before the predetermined time of the transient correction amount for reduction The sum of the tailing correction residual qtrngold · (1-kmw4) corresponding to the fourth predetermined ratio (1-kmw4) of a certain previous transient reduction correction amount (qtrngold) and the current transient correction amount for reduction (qtrng) As
The amount (dlqmwg · kmw3) obtained by subtracting the immediate correction residual (dlqmwg · (1-kmw3)) from the current adhesion increase amount (dlqmwg) and the tailing correction from the previous reduction amount of transient correction (qtrngold) The sum of the remaining amount (qtrngold · (1−kmw4)) (qtrngold · kmw4) and the correction amount for weight reduction is calculated.
Configured as follows.

  According to the device of the present invention having the above-described configuration, the current increase fuel adhesion amount and the previous increase fuel adhesion amount are obtained using the increase cooling water temperature and the increase alcohol concentration, and based on the difference between them. Thus, the increasing correction amount is calculated. The change in cooling water temperature and alcohol concentration with time is sufficiently smaller than the change in load, so the cooling water temperature and alcohol concentration for increasing when the fuel adhesion amount increases, and the increase when the fuel adhesion amount decreases The cooling water temperature and the increasing alcohol concentration are substantially the same value. Therefore, for example, when the load increases by a predetermined amount and then decreases by a predetermined amount, as a result, the increase fuel adhesion amount returns to the value before the increase in load, so the increase correction amount does not gradually increase. .

  Similarly, according to the apparatus of the present invention having the above-described configuration, the current weight loss fuel adhesion amount and the previous weight loss fuel adhesion amount are obtained using the weight reduction cooling water temperature and the weight loss alcohol concentration. A correction amount for weight reduction is calculated based on the difference. The change in cooling water temperature and alcohol concentration over time is sufficiently smaller than the change in load, so the cooling water temperature for weight reduction and alcohol concentration for weight reduction when the fuel adhesion amount decreases, and the weight loss when the fuel adhesion amount increases The cooling water temperature and the weight reducing alcohol concentration are substantially the same value. Therefore, for example, when the load decreases by a predetermined amount and then increases by a predetermined amount, as a result, the fuel adhering amount for reduction returns to the value before the decrease of the load, so the correction amount for reduction does not gradually increase. .

  As described above, according to the device of the present invention, the increase correction amount and the decrease correction amount are calculated independently of each other, so that neither the increase correction amount nor the decrease correction amount is excessive. As a result, the final fuel adhesion correction amount, which is one of the increase correction amount and the decrease correction amount, does not become excessive. Can be solved. ”

  In the above description, in order to help understanding of the present invention, names and / or symbols used in the embodiment are attached to the configuration of the invention corresponding to the embodiment described later in parentheses. However, each component of the present invention is not limited to the embodiment defined by the reference numerals. Other objects, other features and attendant advantages of the present invention will be readily understood from the description of the embodiments of the present invention described with reference to the following drawings.

1 is a schematic configuration diagram of an “internal combustion engine fuel injection amount control device” and an internal combustion engine to which the control device is applied according to an embodiment of the present invention. FIG. 2 is an enlarged view of the injector shown in FIG. 1 and the vicinity of the injector. 3 is a flowchart showing a routine executed by a CPU of the ECU shown in FIG. 2 is a lookup table referred to by the CPU of the ECU shown in FIG. 2 is a lookup table referred to by the CPU of the ECU shown in FIG. It is the graph which showed the relationship between the engine load and the fuel adhesion amount for every cooling water temperature. It is the graph which showed the relationship between the load of an engine, and the amount of fuel adhesion for every alcohol concentration of fuel. It is the flowchart which showed a part of routine which CPU of the modification of embodiment of this invention performs. It is the flowchart which showed a part of routine which CPU of the modification of embodiment of this invention performs.

  An internal combustion engine fuel injection amount control apparatus (hereinafter also referred to as “the present control apparatus”) according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a system in which the present control device is applied to a “4-cycle spark ignition type multi-cylinder (4-cylinder) internal combustion engine 10”. FIG. 1 shows only a cross section of a specific cylinder, but the other cylinders have the same configuration. The internal combustion engine 10 is an engine that can use an alcohol-containing fuel, and a vehicle on which the internal combustion engine 10 is mounted is referred to as FFV.

  The internal combustion engine 10 includes a cylinder block unit 20 including a cylinder block, a cylinder block lower case, an oil pan, and the like, a cylinder head unit 30, an intake system 40 for supplying gasoline mixture to the cylinder block unit 20, and a cylinder And an exhaust system 50 for releasing the exhaust gas from the block unit 20 to the outside.

  The cylinder block unit 20 includes a cylinder 21, a piston 22, a connecting rod 23, and a crankshaft 24. The piston 22 reciprocates in the cylinder 21. The reciprocating motion of the piston 22 is transmitted to the crankshaft 24 through the connecting rod 23. The wall surface of the cylinder 21 and the upper surface of the piston 22 form a combustion chamber 25 together with the lower surface of the cylinder head portion 30.

  The cylinder head unit 30 includes an intake port 31 that communicates with the combustion chamber 25, an intake valve 32 that opens and closes the intake port 31, a variable intake timing device 33 that drives the intake valve 32, an exhaust port 34 that communicates with the combustion chamber 25, and an exhaust port. An exhaust valve 35 that opens and closes 34, an exhaust camshaft 36 that drives the exhaust valve 35, an ignition plug 37, an igniter 38 that includes an ignition coil that generates a high voltage applied to the ignition plug 37, and an injector that injects fuel into the intake port 31 (Fuel injection valve, fuel injection means) 39 is provided. The variable intake timing device 33 includes an intake camshaft, and continuously changes the phase angle and lift amount of the intake camshaft.

  The intake system 40 includes a plurality of intake manifolds 41 having one end connected to the intake port 31 of each cylinder, one surge tank 42 to which the other end of each intake manifold 41 is connected, and an intake having one end connected to the surge tank 42. A pipe 43, an air filter 44 provided at the other end of the intake pipe 43, and a throttle valve 45 in the intake pipe 43 that can change the opening cross-sectional area of the intake passage are provided. The throttle valve 45 is driven to rotate in the intake pipe 43 by a throttle valve actuator 45a made of a DC motor.

  As shown in FIG. 2, a part of the fuel injected from the injector 39 is a “member constituting the intake passage such as the intake manifold 41, the intake port 31, and the intake valve 32 (ie, intake passage constituting member)”. Adhere to.

  Referring again to FIG. 1, the exhaust system 50 includes a plurality of exhaust manifolds 51, exhaust pipes 52, an upstream three-way catalyst 53, and a downstream three-way catalyst 54, one end of which is connected to the exhaust port 34 of each cylinder. It has.

  On the other hand, this system includes a hot-wire air flow meter 61, a throttle position sensor 62, a cam position sensor 63, a crank position sensor 64, a coolant temperature sensor 65, an air-fuel ratio sensor 66, an accelerator pedal operation amount sensor 67, and an alcohol concentration sensor 68. ing.

The hot-wire air flow meter (intake air amount acquisition means) 61 measures the mass flow rate of intake air flowing through the intake pipe 43 and outputs a signal representing the measured intake air amount (intake air flow rate) Ga. It has become.
The throttle position sensor 62 detects the opening of the throttle valve 45 and outputs a signal representing the throttle valve opening TA.

The cam position sensor 63 generates a signal (G2 signal) having one pulse every time the intake camshaft rotates 90 ° (that is, every time the crankshaft 24 rotates 180 °).
The crank position sensor 64 has a narrow pulse every time the crankshaft 24 rotates 10 ° and outputs a signal having a wide pulse every time the crankshaft 24 rotates 360 °. This signal is converted into a signal representing the engine rotational speed NE by an electric control device 70 described later. Further, the electric control device 70 acquires the absolute crank angle of the engine 10 based on the signal from the cam position sensor 63 and the crank position sensor 64.
The coolant temperature sensor 65 detects the coolant temperature of the internal combustion engine 10 and outputs a signal representing the coolant temperature THW.

The air-fuel ratio sensor 66 outputs an output value corresponding to the air-fuel ratio of the exhaust gas.
The accelerator pedal operation amount sensor 67 detects the operation amount of the accelerator pedal Ap operated by the driver, and outputs a signal representing the operation amount Accp of the accelerator pedal Ap.

  The alcohol concentration sensor 68 is disposed in a fuel supply pipe that connects a plurality of fuel injection valves 39 and a fuel tank (not shown). The alcohol concentration sensor 68 outputs a signal Eth representing the concentration of alcohol (ethanol concentration) contained in the fuel. The alcohol concentration sensor 68 is well known (see, for example, Japanese Patent Application Laid-Open No. 2005-201670 and Japanese Patent Application Laid-Open No. 7-77507). The alcohol concentration sensor 68 may be a capacitance type sensor that detects the alcohol concentration based on the dielectric constant of the fuel, and an optical sensor that detects the alcohol concentration based on the refractive index and transmittance of the fuel. It may be.

  The electric control device 70 is a CPU 72, a ROM 72 and a RAM 73 in which a program executed by the CPU 71, a table (look-up table, map), constants, and the like are stored in advance, and data is written while the power is turned on. This is a well-known microcomputer comprising a backup RAM 74 that retains power while the power is cut off, an interface 75 including an AD converter, and the like. The CPU realizes various functions by executing a program.

  The interface 75 is connected to the sensors 61 to 68 and supplies signals from the sensors 61 to 68 to the CPU 71. The electric control device 70 AD-converts a signal from an appropriate sensor among these sensors 61 to 68 every time a predetermined time elapses and acquires a corresponding parameter. The interface 75 sends a drive signal (instruction signal) to the throttle valve actuator 45a, the igniter 38 of each cylinder, the injector 39 of each cylinder, and the like in accordance with an instruction from the CPU 71. In the following description, “cooling water temperature THW” represents the latest value (current value) of the cooling water temperature THW detected by the cooling water temperature sensor 65, and “alcohol concentration Eth” represents the alcohol detected by the alcohol concentration sensor 68. It represents the latest value (current value) of the density Eth. Similarly, “load KL” represents the latest value (current value) of the calculated load KL, and “engine speed NE” represents the latest value (current value) of the acquired engine speed NE.

Further, the electric control device 70 obtains the load (load factor) KL of the internal combustion engine 10 every elapse of a predetermined time by the following equation (B1). In the formula (B1), Mc is the in-cylinder intake air amount, ρ is the air density (unit is (g / l)), L is the exhaust amount of the engine 10 (unit is (l)), and “4” is the engine. The number of cylinders is 10. The in-cylinder intake air amount Mc may be estimated from the intake air amount Ga, the engine rotational speed NE, and a look-up table. The well-known air amount estimation model (air model) is used for the throttle valve opening TA and the engine rotational speed NE. It may be obtained by applying to. In the latter case, the load KL is “a load factor KLforward of a predetermined time ahead of the current time”. Even in this case, the load factor KLforward indicates the actual load KL of the engine 10. Further, instead of the load factor KL, an accelerator pedal operation amount Accp may be used as a parameter representing the load of the engine 10.

KL = (Mc / (ρ · L / 4)) · 100% (B1)

(Operation of this control device)
Next, the actual operation of this control apparatus will be described by focusing on a specific cylinder. A CPU 71 (hereinafter simply referred to as “CPU”) of the present control device performs a fuel injection control routine shown by a flowchart in FIG. 3 according to a predetermined crank angle (for example, the crank angle of a specific cylinder before the intake top dead center). It is repeatedly executed every time it coincides with (BTDC 90 °). Therefore, when the crank angle of an arbitrary cylinder reaches the predetermined crank angle, the CPU starts the process from step 300 and sequentially performs the processes of steps 305 to 355 described below. The CPU executes the same process as the process described below for other arbitrary cylinders for the arbitrary cylinders.

  Step 305: The CPU obtains actual current values (latest values) of parameters such as engine load KL, engine speed NE, cooling water temperature THW, alcohol concentration Eth, and intake air amount Ga. As described above, each parameter is updated each time the sampling time elapses by an AD conversion routine or an interrupt routine (not shown) that is executed every time the sampling time corresponding to each parameter elapses.

  Step 310: The CPU applies the intake air amount Ga and the engine rotational speed NE to the look-up table MAPMc (Ga, NE), thereby calling the cylinder that reaches the intake stroke (hereinafter also referred to as “fuel injection cylinder”). In-cylinder intake air amount (air weight) Mc is calculated. The unit of the cylinder intake air amount Mc is (g). The in-cylinder intake air amount Mc may be obtained using a known air amount estimation model that models the behavior of air in the intake passage of the engine 10. Further, the lookup table described below including this lookup table MAPMc (Ga, NE) is created based on data obtained by experiments and simulations carried out in advance, and stored in the ROM 72.

Step 315: The CPU obtains the increasing water temperature offset amount thwzofs by applying the cooling water temperature THW and the alcohol concentration Eth to the lookup table MAPthwzofs (THW, Eth) shown in FIG. The increasing water temperature offset amount thwzofs is a positive value.
Step 320: The CPU obtains the water amount offset amount thwgofs for weight reduction by applying the coolant temperature THW and the alcohol concentration Eth to the lookup table MAPthwgofs (THW, Eth) shown in FIG. The water temperature offset amount thwgofs for weight reduction is a positive value.

Step 325: The CPU obtains the increasing concentration offset amount ethzofs by applying the cooling water temperature THW and the alcohol concentration Eth to the lookup table MAPethzofs (THW, Eth) shown in FIG. The increasing concentration offset amount ethzofs is a positive value.
Step 330: The CPU obtains the reducing concentration offset amount ethgofs by applying the cooling water temperature THW and the alcohol concentration Eth to the look-up table MAPthwgofs (THW, Eth) shown in FIG. The concentration offset amount ethgofs for weight reduction is a positive value.

Step 335:
The CPU obtains the increasing cooling water temperature thwz by performing correction for subtracting the increasing water temperature offset amount thwzofs from the cooling water temperature THW.
The CPU obtains the cooling water temperature thwg for reducing by performing correction for adding the water temperature offset amount for reducing water amount thwgofs to the cooling water temperature THW.
The CPU obtains the increasing alcohol concentration ethz by performing correction for adding the increasing concentration offset amount ethzofs to the alcohol concentration Eth.
The CPU obtains the reducing alcohol concentration ethg by performing correction for subtracting the decreasing concentration offset amount ethgofs from the alcohol concentration Eth.

  Step 340: The CPU adopts (stores) the increasing coolant temperature thwz as the map-applied coolant temperature THW, and adopts (stores) the increase alcohol concentration ethz as the map-applied alcohol concentration Eth.

  Step 345: The CPU adopts the load KL (the latest value of the actual load), the engine speed NE (the latest value of the actual engine speed NE), the map-applied coolant temperature THW adopted in Step 340, and the Step 340. Based on the map-applied alcohol concentration Eth, the fuel increase correction amount for increase (sometimes simply referred to as “correction amount for increase”) fmwz is obtained according to the following procedure.

  (Procedure C1) The CPU calculates the load KL, the engine rotational speed NE, the map-applied coolant temperature THW adopted in step 340, and the map-applied alcohol concentration Eth adopted in step 340, using a lookup table MAPqmw (KL, THW, Eth , NE) to obtain the current value qmwanow of the estimated value of the fuel adhesion amount. The current value qmwanow of the estimated value of the fuel adhesion amount can also be referred to as “the current fuel adhesion amount for increase”.

  As described above, the table MAPqmw (KL, THW, Eth, NE) is a table that defines the relationship between the combination of the load KL, the cooling water temperature THW, the alcohol concentration Eth, the engine speed NE, and the fuel adhesion amount qmwa. It is. The table MAPqmw (KL, THW, Eth, NE) is a table in which data indicating “relationship between these parameters” obtained based on experiments and simulations performed in advance is stored in the ROM 72 in a lookup table format. It is.

  (Procedure C2) The CPU acquires, as the “previous value qmwaold of the estimated value of the fuel adhesion amount”, the estimated value of the fuel adhesion amount acquired in step 345 when this routine is executed a predetermined time ago. That is, the CPU stores the “current value qmwanow of the estimated value of the fuel adhesion amount” calculated at the time of executing this routine a predetermined time in the RAM 73, and stores the “fuel adhesion amount of the fuel adhesion amount stored in the RAM 73. The current value qmwanow of the estimated value is read as the “previous value qmwaold of the estimated value of fuel adhesion”. The previous value qmwaold of the estimated value of the fuel adhesion amount can also be referred to as the “previous increase fuel adhesion amount”.

(Procedure C3) The CPU calculates “amount of change in fuel adhesion amount (adhesion increase amount) dlqmwz over a predetermined time” according to the following equation (1). That is, the CPU obtains “the difference between these values (that is, the current fuel for increasing the current amount) obtained by subtracting the“ previous value qmwaold of the estimated value of the fuel adhesion amount ”from the“ current value qmwanow of the estimated value of the fuel adhesion amount ”. The difference between the adhesion amount qmwanow and the previous fuel increase amount qmwaold) ”is obtained as the adhesion increase amount dlqmwz.

dlqmwz = qmwanow−qmwaold (1)

(Procedure C4) The CPU calculates the increasing transient correction amount qtrnz according to the following equation (2).

qtrnz = dlqmwz (1-kmw1) + qtrnzold (1-kmw2) (2)

The variables in the above equation (2) are as follows.
kmw1 is a predetermined constant larger than 0 and smaller than 1. The kmw1 may be a value that is changed based on the current values of the coolant temperature THW, the load KL, the alcohol concentration Eth, and the engine rotational speed NE.
qtrnzold is the previous value of the increase transient correction amount qtrnz (the increase transient correction amount qtrnz calculated when this routine is executed a predetermined time before).
kmw2 is a predetermined constant larger than 0 and smaller than 1. The kmw2 may be a value that is changed based on the current values of the coolant temperature THW, the load KL, the alcohol concentration Eth, and the engine speed NE.

(Procedure C5) The CPU calculates an increase fuel adhesion correction amount fmwz (an increase correction amount fmwz) according to the following equation (3).
The first term (dlqmw · kmw1) on the right side of the equation (3) is called an immediate correction term.
The second term (qtrnzold · kmw2) on the right side of equation (3) is called the tailing term.

fmwz = dlqmwz · kmw1 + qtrnzold · kmw2 (3)

  Step 350: The CPU adopts (stores) the cooling water temperature thwg for weight reduction acquired in step 335 as the map applied cooling water temperature THW, and uses the alcohol concentration ethg for weight reduction acquired in step 335 as the map applied alcohol concentration Eth. Adopt (store).

  Step 355: The CPU adopts the load KL (the latest value of the actual load), the engine speed NE (the latest value of the actual engine speed NE), the map-applied coolant temperature THW adopted in Step 350, and the Step 350. Based on the map-applied alcohol concentration Eth, the fuel adhering correction amount for weight reduction (sometimes simply referred to as “correction amount for weight reduction”) fmwg is obtained according to the following procedure.

  (Procedure D1) The CPU calculates the load KL, the engine rotational speed NE, the map-applied cooling water temperature THW adopted in step 350, and the map-applied alcohol concentration Eth adopted in step 350, using a lookup table MAPqmw (KL, THW, Eth , NE), the current value qmwbnow of the estimated value of the fuel adhesion amount is acquired. The current value qmwbnow of the estimated value of the fuel adhesion amount can also be referred to as “the current fuel adhesion amount for weight reduction”.

  (Procedure D2) The CPU acquires the estimated value of the fuel adhesion amount acquired in step 355 at the time when this routine is executed a predetermined time ago as “the previous value qmwbold of the estimated value of the fuel adhesion amount”. That is, the CPU stores “the present value qmwbnow of the estimated value of the fuel adhesion amount” calculated at the time of executing this routine a predetermined time in the RAM 73, and stores the “fuel adhesion amount of the fuel adhesion amount” stored in the RAM 73. The estimated current value qmwbnow ”is read out as“ the previous value qmwbold of the estimated amount of fuel adhesion ”. The previous value qmwbold of the estimated value of the fuel adhesion amount can also be referred to as “the previous fuel adhesion amount for weight reduction”.

(Procedure D3) The CPU calculates “amount of change in fuel adhesion amount (adhesion reduction amount) dlqmwg in a predetermined time” according to the following equation (4). That is, the CPU obtains the “difference between these values (that is, the current fuel for weight reduction) obtained by subtracting the“ previous value qmwbold of the estimated value of fuel adhesion ”from the“ current value qmwbnow of estimated value of fuel adhesion ”. The difference between the adhesion amount qmwbnow and the previous fuel reduction amount attachment qmwbold) is determined as the adhesion reduction amount dlqmwg.

dlqmwg = qmwbnow−qmwbold (4)

(Procedure D4) The CPU calculates a transient correction amount qtrng for reduction according to the following equation (5).

qtrng = dlqmwg · (1-kmw3) + qtrngold · (1-kmw4) (5)

The variables in the above equation (5) are as follows.
kmw3 is a predetermined constant larger than 0 and smaller than 1. The kmw3 may be a value that is changed based on the current values of the coolant temperature THW, the load KL, the alcohol concentration Eth, and the engine rotational speed NE. It should be noted that kmw3 may be equal to or different from kmw1.
qtrngold is a previous value of the transient correction amount qtrng for reduction (a transient correction amount qtrng for reduction calculated when this routine is executed a predetermined time before).
kmw4 is a predetermined constant greater than 0 and less than 1. The kmw4 may be a value that is changed based on the current values of the coolant temperature THW, the load KL, the alcohol concentration Eth, and the engine rotational speed NE. It should be noted that kmw4 may be equal to or different from kmw2.

(Procedure D5) The CPU calculates a fuel reduction correction amount fmwg for reduction (a correction amount fmwg for reduction) according to the following equation (6).
The first term (dlqmw · kmw3) on the right side of the equation (6) is called an immediate correction term.
The second term (qtrngold · kmw4) on the right side of equation (6) is referred to as the tailing term.

fmwg = dlqmwg / kmw3 + qtrngold / kmw4 (6)

  Next, the CPU proceeds to step 360 to determine whether or not the increase correction amount fmwz (the increase fuel adhesion correction amount fmwz) is greater than zero. If the increase correction amount fmwz is greater than 0, the CPU makes a “Yes” determination at step 360 to proceed to step 365 to adopt (set) the increase correction amount fmwz as the final fuel adhesion correction amount fmw. On the other hand, when the increase correction amount fmwz is 0 or less, the CPU makes a “No” determination at step 360 to proceed to step 370 to finally calculate the decrease correction amount fmwg (decrease fuel adhesion correction amount fmwg). Adopted (set) as a typical fuel adhesion correction amount fmw.

  Thereafter, the CPU proceeds from step 365 or step 370 to step 375, and calculates the basic fuel injection amount fbase by dividing the cylinder intake air amount Mc by the target air-fuel ratio (here, stoichiometric air-fuel ratio stoich). Note that the stoichiometric air-fuel ratio stoich in this example is corrected based on the alcohol concentration Eth.

  Next, the CPU proceeds to step 380 and corrects the basic fuel injection amount fbase by the fuel adhesion correction amount fmw (adds the fuel adhesion correction amount fmw to the basic fuel injection amount fbase), thereby calculating the final fuel injection amount finj. To do. When the crank angle of the fuel injection cylinder matches a predetermined crank angle before the intake top dead center by a fuel injection execution routine (not shown), the CPU injects the fuel injection amount finj from the injector 39 provided for the fuel injection cylinder. Inject fuel. Thereafter, the CPU once ends this routine.

  As described above, according to the present control device, the look-up table MAPqmw (KL, THW, Eth, NE) is used, and the increase fuel adhesion correction amount fmwz and the decrease fuel adhesion correction amount fmwg are independent of each other. Is calculated. Therefore, for example, when calculating the increase fuel adhesion correction amount fmwz, the amount of change dlqmwz in the fuel adhesion amount when the load KL increases from the first load KL1 to the second load KL2 by the predetermined amount ΔKL, and the load The amount of change dlqmwz of the fuel adhesion amount when KL decreases from the second load KL2 to the first load KL1 by a predetermined amount ΔKL becomes equal. As a result, since the increase transient correction amount qtrnz does not continuously increase, the fuel injection amount is not excessively corrected. Similarly, when calculating the fuel adhesion correction amount fmwg for reduction, the amount of change dlqmwg in the fuel adhesion amount when the load KL decreases from the second load KL2 to the first load KL1 by a predetermined amount ΔKL, and the load KL Is equal to the amount of change dlqmwg in the amount of adhering fuel when the first load KL1 increases from the first load KL1 to the second load KL2 by a predetermined amount ΔKL. As a result, the transient reduction correction amount qtrng for reduction is not continuously increased, so that the fuel injection amount is not excessively corrected.

  The present invention is not limited to the above embodiment, and various modifications can be employed within the scope of the present invention. For example, instead of “Step 315 and Step 320” in FIG. 3, the CPU sequentially performs the processing of “Step 810 to Step 850” in FIG. 8 described below to increase the water temperature offset amount thwzofs for increasing and the water temperature for decreasing. The offset amount thwgofs may be calculated.

  Step 810: The CPU obtains the increasing water temperature offset basic amount thwzofsb by applying the cooling water temperature THW to the lookup table MAPthwzofsb (THW) indicated by a solid line in the block BL1 of FIG. The increasing water temperature offset basic amount thwzofsb is a positive value. According to this table MAPthwgofsb (THW), the increasing water temperature offset basic amount thwzofsb decreases as the cooling water temperature THW increases. This is because the higher the coolant temperature THW, the smaller the difference in the amount of adhering fuel due to the difference in gasoline volatility (whether it is heavy or light).

  Step 820: The CPU obtains the decreasing water temperature offset basic amount thwgofsb by applying the current value of the cooling water temperature THW to the lookup table MAPthwgofsb (THW) indicated by a broken line in the block BL1 of FIG. The water amount offset basic amount thwgofsb for weight reduction is a positive value. According to this table MAPthwgofsb (THW), the lowering water temperature offset basic amount thwgofsb decreases as the cooling water temperature THW increases. This is because the higher the coolant temperature THW, the smaller the difference in the amount of adhering fuel due to the difference in gasoline volatility (whether it is heavy or light).

  Step 830: The CPU obtains a water temperature correction coefficient (water temperature offset amount correction coefficient) kthwofs by applying the current value of the alcohol concentration Eth to the lookup table MAPkthwofs (Eth) shown in the block BL2 of FIG. According to this table MAPkthwofs (Eth), the higher the alcohol concentration Eth, the smaller the water temperature correction coefficient kthwofs. This is because the higher the alcohol concentration Eth, the less the influence of the difference in gasoline volatility (whether it is heavy or light) on the fuel adhesion amount.

  Step 840: The CPU calculates the increasing water temperature offset amount thwzofs by correcting the increasing water temperature offset basic amount thwzofsb by the water temperature correction coefficient kthwofs (multiplying the increasing water temperature offset basic amount thwzofsb by the water temperature correction coefficient kthwofs).

  Step 850: The CPU corrects the water amount offset basic amount thwgofsb for weight reduction by the water temperature correction coefficient kthwofs (multiplies the water amount correction basic amount thwgofsb for weight reduction by the water temperature correction coefficient kthwofs) to calculate the water temperature offset amount for weight reduction thwgofs.

  Further, the CPU performs the processing of “step 910 to step 950” of FIG. 9 described below in order instead of “step 325 and step 330” of FIG. 3 to thereby increase the concentration offset amount ethzofs for increasing and the concentration for decreasing. The offset amount ethgofs may be calculated.

  Step 910: The CPU obtains the increasing concentration offset basic quantity ethzofsb by applying the current value of the cooling water temperature THW to the lookup table MAPethzofsb (THW) indicated by a solid line in the block BL3 of FIG. The increasing concentration offset basic amount ethzofsb is a positive value. According to this table MAPethzofsb (THW), the increasing concentration offset basic amount ethzofsb is substantially constant regardless of the cooling water temperature THW. This is because the detection accuracy of the alcohol concentration Eth of the alcohol concentration sensor 68 does not depend on the cooling water temperature THW.

  Step 920: The CPU obtains the reduction concentration basic amount ethgofsb by applying the cooling water temperature THW to the lookup table MAPethgofsb (THW) indicated by a broken line in the block BL3 of FIG. The concentration offset basic amount ethgofsb for weight reduction is a positive value. According to this table MAPethgofsb (THW), the concentration offset basic amount ethgofsb for weight reduction is substantially constant regardless of the cooling water temperature THW. This is because the detection accuracy of the alcohol concentration Eth of the alcohol concentration sensor 68 does not depend on the cooling water temperature THW.

  Step 930: The CPU obtains a concentration correction coefficient (concentration offset amount correction coefficient) kethofs by applying the current value of the alcohol concentration Eth to the lookup table MAPkethofs (Eth) shown in the block BL4 of FIG. According to this table MAPkethofs (Eth), the concentration correction coefficient kethofs increases as the alcohol concentration Eth increases. This is because the higher the alcohol concentration Eth, the greater the influence of the detection error of the alcohol concentration Eth of the alcohol concentration sensor 68 on the estimated value of the fuel adhesion amount.

  Step 940: The CPU calculates the increasing density offset amount ethzofs by correcting the increasing density offset basic amount ethzofsb by the density correction coefficient kethofs (multiplying the increasing density offset basic quantity ethzofsb by the density correction coefficient kethofs).

Step 950: The CPU corrects the decrease density basic amount ethgofsb by the density correction coefficient kethofs (multiplies the decrease density concentration basic quantity ethgofsb by the density correction coefficient kethofs) to calculate the decrease density offset amount ethgofs.
In this way, each offset amount may be acquired.

  Further, the CPU estimates the alcohol concentration based on the feedback correction amount (or its learned value) in the known air-fuel ratio feedback control based on the output value of the air-fuel ratio sensor 66 without using the alcohol concentration sensor 68. Also good. This estimation method is well known, but is a method for estimating the alcohol concentration based on the feedback correction amount based on the knowledge that the theoretical air-fuel ratio changes when the alcohol concentration is different, so that the feedback correction amount also changes (for example, JP, 2011-52671, JP, 2010-127160, JP, 2010-25062, JP, 2009-228592, etc.).

  Further, in step 380, the basic fuel injection amount fbase is corrected only by the fuel adhesion correction amount fmw, but the basic fuel injection amount may be further corrected by another correction amount (for example, the above-described feedback correction amount). Good. Furthermore, the water temperature offset amount thwzofs for increasing, the water temperature offset amount thwgofs for decreasing, the concentration offset amount ethzofs for increasing, and the concentration offset amount ethgofs for decreasing are all required to be positive values. It may be obtained as a negative value. In this case, the process for adding the offset amount in step 335 is changed to a process for reducing the offset amount, and the process for reducing the offset amount in step 335 is changed to a process for adding the offset amount.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 31 ... Intake port, 32 ... Intake valve, 39 ... Injector, 41 ... Intake manifold, 63 ... Cam position sensor, 64 ... Crank position sensor, 65 ... Coolant temperature sensor, 68 ... Alcohol concentration sensor, 70 ... Electric control device.

Claims (3)

A fuel injection valve for injecting fuel containing alcohol into the intake passage of the internal combustion engine;
Relationship between the load of the engine, the rotational speed of the engine, the temperature of the cooling water of the engine, and the alcohol concentration of the fuel, and the amount of fuel adhering to the member constituting the intake passage Storage means for storing
The actual load that is the actual load of the internal combustion engine, the actual engine rotation speed that is the actual rotation speed of the engine, the actual cooling water temperature that is the actual cooling water temperature of the internal combustion engine, and the actual alcohol concentration of the fuel Parameter acquisition means for repeatedly acquiring a certain actual alcohol concentration;
The latest value of the actual load, the latest value of the actual engine rotational speed, the value according to the latest value of the actual cooling water temperature, and the value according to the latest value of the actual alcohol concentration are applied to the relationship to apply the fuel adhesion. Correction amount calculating means for calculating a fuel adhesion correction amount according to the amount of change in the amount;
A basic fuel injection amount for obtaining an air-fuel ratio of an air-fuel mixture supplied to the engine based on at least the actual load to a predetermined target air-fuel ratio is acquired and the basic fuel injection amount is corrected by the fuel adhesion correction amount. Injection amount control means for injecting the fuel injection amount of fuel obtained by the above-mentioned fuel injection valve;
A fuel injection amount control device for an internal combustion engine, comprising:
The correction amount calculating means includes
Based on the latest value of the actual cooling water temperature and the latest value of the alcohol concentration, obtain a water temperature offset amount for increasing,
Calculate the cooling water temperature for increasing by changing the latest value of the actual cooling water temperature by the offset water temperature offset amount,
Based on the latest value of the actual cooling water temperature and the latest value of the alcohol concentration, obtain a concentration offset amount for increasing,
Calculating the alcohol concentration for increasing by changing the latest value of the actual alcohol concentration by the concentration offset amount for increasing;
By applying the increase coolant temperature, the increase alcohol concentration, the latest value of the actual load, and the latest value of the actual engine rotation speed to the relationship, the fuel increase amount for the current increase is estimated. ,
Based on the difference between the current increase fuel adhesion amount and the previous increase fuel adhesion amount, which is the increase fuel adhesion amount estimated at a predetermined time before, the fuel adhesion correction amount candidates Calculating the correction amount for increasing as
Correction amount calculation means for increasing, and
Based on the latest value of the actual cooling water temperature and the latest value of the alcohol concentration, obtain a water temperature offset amount for weight reduction,
Calculate the cooling water temperature for weight reduction by changing the latest value of the actual cooling water temperature by the amount of water temperature offset for weight reduction,
Based on the latest value of the actual cooling water temperature and the latest value of the alcohol concentration, obtain a concentration offset amount for weight reduction,
Calculating the alcohol concentration for weight reduction by changing the latest value of the actual alcohol concentration by the concentration offset amount for weight reduction;
By applying the weight-reducing cooling water temperature, the weight-reducing alcohol concentration, the latest value of the actual load, and the latest value of the actual engine rotational speed to the relationship, the current weight-reducing fuel adhesion amount is estimated. ,
Based on the difference between the current amount of fuel attachment for weight reduction and the previous amount of fuel attachment for weight reduction that was estimated at the time before the predetermined time, the fuel adhesion correction amount Calculating a correction amount for weight loss as a candidate,
Correction amount calculation means for weight loss,
With
The injection amount control means includes
One of the correction amount for increase and the correction amount for decrease is adopted as the fuel adhesion correction amount.
Fuel injection amount control device. The fuel injection amount control device according to claim 1,
The injection amount control means includes
When the increase correction amount is a value that increases the basic fuel injection amount, the increase correction amount is employed as the fuel adhesion correction amount;
When the increase correction amount is a value that does not increase the basic fuel injection amount, the decrease correction amount is employed as the fuel adhesion correction amount.
Configured as
Fuel injection amount control device. In the fuel injection amount control device according to claim 1 or 2,
The increasing correction amount calculating means includes
The difference between the current increase fuel adhesion amount (qmwanow) and the previous increase fuel adhesion amount (qmwaold) is calculated as the current increase adhesion amount (dlqmwz),
The immediate correction remainder (dlqmwz · (1-kmw1)) corresponding to the first predetermined ratio (1-kmw1) of the current adhesion increase amount (dlqmwz), and the value before the predetermined time of the transient correction amount for increase The sum of the tailing correction residual qtrnzold · (1-kmw2) corresponding to a second predetermined ratio (1-kmw2) of a certain previous increase transient correction amount (qtrnzold) and the current increase transient correction amount (qtrnz) As
The amount (dlqmwz · kmw1) obtained by subtracting the immediate correction residual (dlqmwz · (1-kmw1)) from the current adhesion increase amount (dlqmwz) and the tailing correction from the previous transient increase correction amount (qtrnzold). The sum of the amount obtained by subtracting the remainder (qtrnzold · (1−kmw2)) (qtrnzold · kmw2) and the correction amount for increase is calculated.
Configured as
The weight reduction correction amount calculation means includes:
The difference between the current weight loss fuel adhesion amount (qmwbnow) and the previous weight loss fuel adhesion amount (qmwbold) is calculated as the current adhesion increase amount (dlqmwg),
The immediate correction remainder (dlqmwg · (1-kmw3)) corresponding to the third predetermined ratio (1-kmw3) of the current adhesion increase amount (dlqmwg) and the value before the predetermined time of the transient correction amount for reduction The sum of the tailing correction residual qtrngold · (1-kmw4) corresponding to the fourth predetermined ratio (1-kmw4) of a certain previous transient reduction correction amount (qtrngold) and the current transient correction amount for reduction (qtrng) As
The amount (dlqmwg · kmw3) obtained by subtracting the immediate correction residual (dlqmwg · (1-kmw3)) from the current adhesion increase amount (dlqmwg) and the tailing correction from the previous reduction amount of transient correction (qtrngold) The sum of the remaining amount (qtrngold · (1−kmw4)) (qtrngold · kmw4) and the correction amount for weight reduction is calculated.
Configured as
Fuel injection amount control device.