JPH07229435A - Fuel supply control device of internal combustion engine - Google Patents

Abstract

PURPOSE:To improve stability at idling by preventing air-fuel ratio from becoming rich or lean due to the effect of fuel sticking quantity on the wall in an intake pipe based on variation of external load. CONSTITUTION:An engine 1 is provided with an injector 17 for fuel supply, an air flow meter 32, a water temperature sensor 35, and the like. An electronic control unit(ECU) 51 detects starting and then computes a synthetic fuel increase quantity after starting. Further, each load equivalent value is computed based on the intake air quantity and the like, in addition, a no load equivalent value in the operating condition corresponding to the value is computed from a previously memorized map, and a load ratio equivalent to the degree of load is computed from both values. A load fuel increase quantity factor is computed according to the load ratio and reflected on the synthetic fuel increase quantity after starting. Hereby, when a load is added to the engine, fuel is supplied not only corresponding to the load, but corresponding to fine variation of the load equivalent value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply control device for an internal combustion engine, and more particularly to a fuel supply control device for an internal combustion engine which increases the fuel supply amount after the internal combustion engine is started.

[0002]

2. Description of the Related Art Conventionally, as this type of technique, for example, one disclosed in Japanese Patent Laid-Open No. 2-49942 is known. In this technique, the fuel supply amount is increased over a predetermined period after the engine is started. Further, the external load detecting means detects the operating state of the external load such as the air conditioner. Then, when the operation of the external load is detected by the detection means, the increase value of the supply amount is further increased and corrected based on the increase coefficient (K _HAC ).

Generally, when an external load is activated, the pressure in the intake pipe rises and the atomization characteristic of the fuel deteriorates. However, the reduced atomization characteristic is corrected by the increase correction of the increase value. Can be compensated. As a result, it becomes possible to improve the starting characteristics after the engine is started.

That is, when an external load such as an air conditioner or power steering is applied during idling, the intake air amount is increased in order to prevent the engine speed from dropping. For example, in an engine equipped with an idle speed control device (hereinafter, referred to as “ISC device”) that feedback-controls the rotation speed during idling to a predetermined target rotation speed, the intake valve that controls the ISC device and bypasses the throttle valve is used. The amount of air is increased. At this time, the negative pressure decreases due to the increase in the intake air amount, the fuel in the intake pipe to be sucked into the combustion chamber decreases, and the fuel adhesion amount to the wall surface in the intake pipe increases. In particular, when the engine is cold immediately after the engine is started, the original amount of fuel adhered is small and the atomization of fuel is poor.
Therefore, the amount of fuel adhering to the wall surface (wall surface adhering amount) further increases, the air-fuel ratio becomes lean, and the engine rotation during idling may become unstable.

Therefore, conventionally, in response to an increase in the amount of adhered wall surface, a certain amount of fuel is increased when an external load is applied to ensure idle stability after engine startup.

Further, there is a difference in the degree of load between when the engine is cold immediately after starting and when it is warmed up. That is,
Even when the same external load is applied, the load on the engine is greater in the cold state immediately after the engine is started than in the engine warmed up, due to the influence of the viscosity of the lubricating oil in the engine.
In particular, in an external load using oil such as power steering and torque converter, the oil has a high viscosity in the cold state, like the lubricating oil in the engine. Therefore, when the engine is cold, these external loads further impose a heavy burden on the engine. In this way, the load on the external load changes depending on the temperature conditions of the engine and auxiliary equipment loads, the intake air amount and the negative pressure change, and the wall surface attachment amount in the intake pipe fluctuates.

Therefore, when the external load increases, as in the case where the shift position is shifted from the neutral range (N range) to the drive range (D range) after the engine is started, the cooling water temperature at the time of engine start is adjusted. It is also conceivable to calculate the coefficient, consider the influence of the viscosity of the oil of the engine or the like, and further increase and correct the increase value based on the coefficient. That is, for example, the increase amount after the engine is started is further increased by a coefficient determined by the water temperature at the start. Alternatively, an independent increase amount other than the post-start increase amount corresponding to the shift from the N range to the D range is added to the post-start increase amount. Even with such a correction, it becomes possible to prevent the air-fuel ratio from becoming lean due to a change in the external load after the engine is started and improve the starting characteristics.

[0008]

However, in the prior art in the former publication, the increase coefficient (K _HAC ) adopted when the external load is activated is always a constant value. Further, in the latter conventional technique, the coefficient and the like can be calculated according to the cooling water temperature and the like at the time of starting, but thereafter have a constant value.

Therefore, none of the techniques can cope with the change in the external load after the predetermined amount increase is executed. Therefore, it is difficult to perform an appropriate increase correction according to the change in the wall surface adhesion amount in the intake pipe due to the change in the engine load. As a result, the air-fuel ratio becomes unnecessarily rich, and the amount of adhesion on the wall surface increases and becomes lean, which makes the idle rotation unstable and makes it difficult to obtain good starting characteristics after engine startup. There was a risk that it would not happen.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide a fuel supply control device for an internal combustion engine, which is adapted to increase the fuel supply amount when an external load is applied during idling. By increasing the amount according to the change in the negative pressure in the intake pipe with respect to the change in external load, the air-fuel ratio is prevented from becoming rich or lean due to the effect of the amount of wall adhering to the intake pipe, and stability is particularly good at idle. An object of the present invention is to provide a fuel supply control device for an internal combustion engine, which can be any of the above.

[0011]

In order to achieve the above object, in the present invention, as shown in FIG.
1. A fuel supply control device for an internal combustion engine, comprising a fuel supply means M3 for supplying fuel into one intake pipe M2, and increasing the fuel supply amount by adding an external load M4 to the internal combustion engine M1 during idling, Load detection means M5 for detecting the degree of load of the internal combustion engine M1 which is affected by the state of application of the external load M4 to the internal combustion engine M1.
An operating state detecting means M6 for detecting an operating state of the internal combustion engine M1, and an operating state of the internal combustion engine M1.
A storage unit M7 that stores in advance the relationship of the degree of the load of the internal combustion engine M1 when the external load M4 is not applied, and the operating state detected by the operating state detection unit M6 based on the storage unit M7. Of the load of the internal combustion engine M1 in a state in which the external load M4 is not applied at all, and the ratio of the load level of the internal combustion engine M1 detected by the load detection means M5 to the calculation result is calculated. Load ratio calculating means M8 for calculating,
An increase amount that determines whether to apply the external load M4 based on the ratio calculated by the load ratio calculating means M8 and calculates an increase amount of the fuel supply amount according to the ratio when it is determined that the external load M4 is added Quantity calculation means M
9 and an increase correction unit M10 for increasing and correcting the fuel supply amount according to the increase amount calculated by the increase amount calculation unit M9.
The point is that the and are provided.

[0012]

According to the above structure, as shown in FIG. 1, the fuel is supplied by the fuel supply means M3 into the intake pipe M2 of the internal combustion engine M1. Further, the fuel supply amount is basically increased by adding the external load M4 to the internal combustion engine M1 during idling.

In the present invention, the load detecting means M5 detects the degree of the load of the internal combustion engine M1 which is influenced by the state of application of the external load M4 to the internal combustion engine M1. Further, the operating state detecting means M6 detects the operating state of the internal combustion engine M1. Further, the storage means M7 stores in advance the relationship between the operating state of the internal combustion engine M1 and the degree of the load of the internal combustion engine M1 when the external load M4 is not applied at all.

Then, in the load ratio calculating means M8, the degree of load of the internal combustion engine M1 in the operating state detected by the operating state detecting means M6 in the state where no external load M4 is applied is detected based on the storing means M7. The ratio of the degree of the load of the internal combustion engine M1 detected by the load detection means M5 to the calculated result is calculated. further,
The increase amount calculation means M9 determines whether to apply the external load M4 based on the ratio calculated by the load ratio calculation means M8, and when it is determined that the external load M4 is added, the amount of fuel supply is changed according to the ratio. The amount of increase is calculated. Then, in the increase correction means M10, the fuel supply amount is increased and corrected in accordance with the increase amount calculated by the increase calculation means M9.

Therefore, the amount of increase corresponding to the change in the load at that time is calculated. Therefore, the fuel increase value corresponding to the load is obtained, and the fuel is supplied based on the value.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a fuel supply control device for an internal combustion engine according to the present invention is embodied in a gasoline engine will be described in detail below with reference to the drawings.

FIG. 2 is a schematic configuration diagram showing a fuel supply control device for the engine 1 as an internal combustion engine in this embodiment. An engine 1 mounted on an automobile has a plurality of cylinders, and a cylinder block 2 constituting the engine 1 has cylinder bores 3 for the number of cylinders. A cylinder head 4 is attached to the upper side of the cylinder block 2 so as to close each cylinder bore 3. A piston 5 is provided in each cylinder bore 3 so as to be vertically movable, and the piston 5 is connected to a crankshaft (not shown) via a connecting rod 6. Inside the cylinder bore 3, a space surrounded by the piston 5 and the cylinder head 4 is a combustion chamber 7. Lubricating oil in an oil pan (not shown) is supplied to each part such as the cylinder bore 3 and the connecting rod 6 when the engine 1 is in operation.

The cylinder head 4 is provided with spark plugs 8 corresponding to the respective combustion chambers 7. Also,
The cylinder head 4 is provided with an intake port 9 and an exhaust port 10 that communicate with each combustion chamber 7, and an intake pipe 11 and an exhaust pipe 12 are connected to and connected to these ports 9 and 10, respectively. Further, an intake valve 13 and an exhaust valve 14 for opening and closing are provided at the respective open ends of the intake port 9 and the exhaust port 10 that communicate with the combustion chamber 7. These intake valve 13 and exhaust valve 1
4 is opened and closed in conjunction with the rotation of the crankshaft by a valve operating device including a camshaft (not shown). The opening / closing timing of each of the valves 13 and 14 is opened / closed in synchronization with the rotation of the crankshaft. That is, the valves 13 and 14 are adapted to be opened and closed at a predetermined timing in synchronization with a series of strokes of an intake stroke, a compression stroke, an explosion / expansion stroke and an exhaust stroke.

An air cleaner 15 is provided on the inlet side of the intake pipe 11.
Is provided. A surge tank 16 is provided in the middle of the intake pipe 11 for smoothing the pulsation of air passing through the passage 11. Further, on the downstream side of the surge tank 16, injectors 17 as fuel supply means for fuel injection are provided near the intake port 9 for each cylinder. These injectors 1
A fuel tank (not shown) supplies a fuel having a predetermined pressure to the fuel tank 7. on the other hand,
At the outlet side of the exhaust pipe 12, a catalytic converter 18 having a three-way catalyst for purifying exhaust gas is provided.

The engine 1 has an air cleaner 15
The outside air taken in from is introduced through the intake pipe 11 including the surge tank 16. Further, the fuel is injected from each injector 17 at the same time as the introduction of the outside air, so that the mixture of the outside air and the fuel is taken into the combustion chamber 7 in synchronization with the opening of the intake valve 13 in the intake stroke.
Further, the air-fuel mixture taken into the combustion chamber 7 is ignited by the spark plug 8.
When the engine 1 is ignited by the engine, the air-fuel mixture explodes and burns to provide the engine 1 with driving force. And the explosion
The exhaust gas after combustion is the exhaust valve 14 in the exhaust stroke.
The exhaust pipe 1 in synchronization with the opening of the exhaust pipe 1
2 is discharged to the outside through the catalytic converter 18 and the like.

On the upstream side of the surge tank 16, there is provided a throttle valve 19 which opens and closes in conjunction with the operation of an accelerator pedal (not shown). Then, by opening and closing the throttle valve 19, the intake amount of outside air into the intake pipe 11, that is, the intake air amount Q is adjusted.

A throttle sensor 31 for detecting the opening of the valve 19, that is, the throttle opening TA is provided near the throttle valve 19. The throttle sensor 31 outputs a signal of the throttle opening TA and outputs an idle signal by an idle contact that is turned on only when the throttle valve 19 is at the fully closed position. Further, an air flow meter 32 that detects an intake air amount Q into the intake pipe 11 is provided downstream of the air cleaner 15. In addition, an intake air temperature sensor 33 that detects the temperature of the air taken into the intake pipe 11, that is, the intake air temperature THA is provided between the air cleaner 15 and the air flow meter 32.

Further, in the middle of the exhaust pipe 12, an oxygen sensor 34 for detecting the oxygen concentration OX in the exhaust, that is, for detecting the exhaust air-fuel ratio in the exhaust pipe 12 is provided. Further, the cylinder block 2 is provided with a water temperature sensor 35 that detects the temperature of the cooling water of the engine 1, that is, the cooling water temperature THW.

The ignition signal distributed by the distributor 20 is applied to the ignition plug 8 for each cylinder. The distributor 20 is for distributing the high voltage output from the igniter 21 to each spark plug 8 in synchronization with the rotation of the crankshaft, that is, the crank angle. The ignition timing of each spark plug 8 is determined by the high voltage output timing from the igniter 21.

The distributor 20 incorporates a rotor (not shown) which rotates in association with the rotation of the crankshaft. Then, the distributor 20
A rotation speed sensor 36 for detecting the rotation speed of the engine 1, that is, the engine rotation speed NE from the rotation of the rotor is provided. Similarly, the distributor 20 is provided with a cylinder discrimination sensor 37 that detects a crank angle reference signal of the engine 1 at a predetermined rate according to the rotation of the rotor. In this embodiment, the crankshaft rotates twice for a series of strokes in the engine 1, and the rotation speed sensor 36 detects the crank angle at a rate of 30 ° CA per pulse. The cylinder discrimination sensor 37 detects the crank angle at a rate of 360 ° CA per pulse.
Further, the automatic transmission 25 drivingly connected to the engine 1 is provided with a vehicle speed sensor 38 for detecting the speed of the vehicle, that is, the vehicle speed SP.

In addition, the intake pipe 11 of this embodiment is provided with a bypass passage 22 that bypasses the throttle valve 19 and connects the upstream side and the downstream side of the valve 19 to each other. A well-known linear solenoid type idle speed control valve (ISCV) 23 is provided in the middle of the bypass passage 22. And ISC
The bypass passage 22 is opened and closed by driving and controlling V23 based on a predetermined control signal. This ISCV 23 is operated to stabilize the idling state of the engine 1 when the throttle valve 19 is fully closed, and feedback control of the actual rotational speed is performed so as to attain the target rotational speed at idling. Is. Therefore, when the engine 1 is idling, the amount of air flowing through the bypass passage 22 is adjusted by controlling the opening degree of the ISCV 23 and the valve opening time thereof, that is, by performing the ISC control, and intake air to the combustion chamber 7 is adjusted. The quantity Q is adjusted.

At the same time, the engine 1 is provided with a starter 24 for applying a rotational force to the engine 1 by cranking at the time of starting the engine. Further, the starter 24 is provided with a starter switch 39 for detecting the operation / non-operation of the starter 24. As is well known, the starter switch 39 is turned on / off by operating an ignition switch (not shown), and the starter 24 is operated while the ignition switch is being operated. The starter signal STS of "on" is output.

The automatic transmission 25 constitutes a part of an external load together with, for example, an air conditioner (air conditioner) which is not shown. In addition, a neutral start switch 40 is provided inside the automatic transmission 7. The neutral start switch 40 detects that the current shift position ShP is in the neutral range [N range (including P range)]. That is, it is possible to detect whether the current shift position ShP is in the N range or the drive range (D range).

The injector 17, the igniter 21, and the ISCV 23 are electronic control units (hereinafter simply referred to as "EC
U ”) 51, and their drive timing is controlled by the operation of the ECU 51. The ECU 51 constitutes a storage unit, a load ratio calculation unit, an increase amount calculation unit, and an increase correction unit. This ECU
Reference numeral 51 indicates the throttle sensor 31, the air flow meter 32, the intake air temperature sensor 33, the oxygen sensor 34, the water temperature sensor 35, the rotation speed sensor 36, the cylinder discrimination sensor 37, the vehicle speed sensor 38, the starter switch 39, and the neutral start switch 40 (these are described above). All or a part of the above) constitutes an operating state detecting means and a load detecting means). Then, the ECU 51 controls the ignition timing of the engine 1, the fuel injection amount control, the ISC control, and the like based on the output signals from the sensors 31 to 38, the starter switch 39, and the neutral start switch 40, and the injectors 17 and the igniter. 21 and ISC
The V23 is preferably driven and controlled.

Here, the electrical configuration of the ECU 51 will be described with reference to the block diagram of FIG. The ECU 51 includes a central processing unit (CPU) 52, a read-only memory (ROM) 53 that stores a predetermined control program and the like in advance, and a random access memory (R) that temporarily stores calculation results of the CPU 52 and the like.
AM) 54, a backup RAM 55 for storing the stored data, a timer counter 56, etc., and these units, an external input circuit 57, an external output circuit 58, etc. are connected by a bus 59 as a theoretical operation circuit. . In this embodiment, the ROM 53 stores in advance a program relating to fuel injection amount control, such as a "post-starting increase value calculation routine", which will be described later, a program relating to ignition timing control, or a predetermined map. Further, in this embodiment, the timer counter 56 outputs an interrupt signal at every predetermined time and simultaneously performs a plurality of counting operations.

The external input circuit 57 includes the above-mentioned throttle sensor 31, air flow meter 32, and intake air temperature sensor 3.
3, oxygen sensor 34, water temperature sensor 35, rotation speed sensor 3
6, a cylinder discrimination sensor 37, a vehicle speed sensor 38, a starter switch 39, a neutral start switch 40, etc. are connected. In addition, the external output circuit 58 includes the injectors 17, the igniter 21, and the ISCV.
23 are connected to each other.

Then, the CPU 52 reads the respective signals from the sensors 31 to 38, the starter switch 39 and the neutral start switch 40, which are input via the external input circuit 57, as input values. Further, the CPU 51 suitably drives and controls each injector 17, the igniter 21, and the ISCV 23 based on the read input values.

Next, a processing operation for controlling the fuel injection (supply) amount in the engine fuel supply control device configured as described above will be described with reference to FIGS. FIG. 4 is a flowchart for explaining the “post-start increase amount calculation routine” executed by the ECU 51 from the time of starting to the time of idling, and this routine is executed by a regular interruption every predetermined time.

When the processing shifts to this routine, first, at step 101, the starter switch 39, the water temperature sensor 35, the air flow meter 32, and the rotation speed sensor 36.
The starter signal STS, the cooling water temperature THW, the intake air amount Q, the engine speed NE, etc. are read based on the respective signals from the above. Further, the idle signal based on the detection result of the throttle sensor 31 is read.

Next, at step 102, it is judged whether or not the present time is idling based on the idle signal read this time. Then, if the current time is not during idling, it is assumed that the current increase correction is not performed, and the subsequent processing is temporarily ended. If the current time is idling, the process proceeds to the next step 103.

However, at the time of idling, feedback control (ISC control) of the ISCV 23 is performed in a separate routine. That is, when the shift position ShP is shifted from the N range to the D range,
The ECU 51 determines that the external load has increased. When the engine speed NE is lower than the predetermined target idle speed, the ECU 51 drives and controls the ISCV 23 so as to increase the intake air amount in order to increase the engine speed NE.

In the next step 103, it is determined whether or not the starter signal STS read this time is "ON". That is, it is determined whether or not the engine 1 is started in this routine. Then, when the starter signal STS is "ON", it is determined that the engine 1 is currently started, and the process proceeds to step 104.
In step 104, the cooling water temperature T read this time
Based on HW, the initial value of the post-basic-start-up increase value FASE is calculated. Here, the initial value of the post-basic-start-up increase value FASE is calculated by referring to a map (not shown) preset for the cooling water temperature THW. Then, the subsequent processing is temporarily terminated.

On the other hand, in step 103, when the starter signal STS is not "ON", it is judged that the start is currently made, and the routine proceeds to step 105.
In step 105, the cooling water temperature T read this time is read.
The warm-up increase value FWL is calculated based on HW. This warm-up increase value FWL is an increase value for promoting warm-up,
Similar to the case of the initial value of the increased amount FASE after the basic start,
It is calculated by referring to a map (not shown) preset for the cooling water temperature THW.

In the following step 106, a predetermined value α is set from the post-basic-start-up increase value FASE in the previous routine.
The value obtained by subtracting is set as a new basic post-start increase amount FASE. That is, each time the routine is repeated, the post-basic-start amount increase FASE gradually decreases.

Next, at step 107, the load equivalent value GN corresponding to the load of the engine 1 is calculated based on the intake air amount Q and the engine speed NE which are read this time (this constitutes the load detecting means. ). here,
The load equivalent value GN is the intake air amount Q and the engine speed N.
It is calculated according to a predetermined calculation formula based on E and the like.

In step 108, the no-load equivalent value GNS is calculated based on the cooling water temperature THW read this time.
Calculate TN. As shown in FIG. 5, in a completely unloaded state (for example, the shift position ShP is in the N range and the air conditioner or the like is not operating), it is previously determined based on the intake air amount Q or the like with respect to the cooling water temperature THW at that time. The actually measured data is stored in the ROM 53 as a map of the no-load equivalent value GNSTN (this constitutes storage means). Then, the no-load equivalent value GNSTN in the step is calculated by referring to this map.

Then, in step 109, the load equivalent value GN and the no-load equivalent value GNS calculated respectively this time.
The load ratio RGNSTD is calculated based on TN. More specifically, a value obtained by dividing the load equivalent value GN by the no-load equivalent value GNSTN is set as the load ratio RGNSTD (this constitutes the load ratio calculating means). Therefore, as shown in FIG. 6, when the load is not applied at all, the load ratio RGNSTD is almost “1.0”. Also, when the shift position ShP is shifted from the N range to the D range, or when the air conditioner is operated,
When a load is applied, the load ratio RGNSTD becomes larger than “1.0”.

Next, at step 110, the load increase coefficient KFASED is calculated based on the load ratio RGNSTD calculated this time. Here, this load increase coefficient K
FASED is calculated, for example, as shown in FIG. 7, by referring to a map preset according to the load ratio RGNSTD at that time.

Then, at step 111, the load increase coefficient K is added to the basic post-start increase amount FASE calculated this time.
The value obtained by multiplying FASED is the load increase value after starting FASED
Set as.

Further, at step 112, the warm-up increase value FWL calculated this time and the post-start load increase value FAS are calculated.
Based on the ED and the like, the post-start total increase value FTOTAL is calculated. That is, a value obtained by adding "1" to the sum of the warm-up increase value FWL and the post-start load increase value FASED is set as the post-start total increase value FTOTAL (these steps 1
The processes 10 to 112 particularly constitute the amount increase calculation means). Then, the subsequent processing is temporarily terminated.

As described above, in the above-mentioned "post-start increase amount calculation routine", the post-start total increase amount FTOTAL is calculated according to the load equivalent value GN at that time. Then, based on that value, the fuel injection amount control is executed in a separate routine (this constitutes the increase correction means).

As described above, in the present embodiment, the post-start total increase value FTOTAL is calculated during the idling state from when the start of the engine 1 is detected to when the predetermined time elapses. In this calculation, first, the operating state at that time (cooling water temperature TH
The basic post-start-up amount FASE that is calculated according to W) and gradually decreases over time is taken into consideration. Therefore, with this kind of basic increase in the amount of fuel, the stall of the engine 1 due to the reduction in atomization can be prevented, and a smooth transition to acceleration immediately after starting can be achieved.

Further, the load equivalent value GN at that time is calculated, and the corresponding value (no load equivalent value) GNSTN in the no-load state in the corresponding operating state is calculated, and both correspond to the degree of load. Load ratio RGN
STD is calculated. Then, according to the load ratio RGNSTD which is the degree of the load, the load increase coefficient KFASED
Is calculated and the post-start load increase value FASED is set. Therefore, when the shift position ShP is shifted from the N range to the D range, or when the load is applied such as when the air conditioner is operated, the post-start load increase value FASED corresponding to the load is set. . Not only that, but also for a slight change in the load equivalent value GN, it is possible to set the post-start load increase value FASED corresponding to the slight change at that time.

Therefore, the appropriate post-start load increase value FA
The post-startup total increase value FTOTAL based on the SED is obtained, and optimal fuel supply can be performed. for that reason,
It is possible to prevent lean or rich air-fuel ratio,
The air-fuel ratio can be adjusted to an optimum value. As a result, it is possible to promptly respond to acceleration, improve exhaust emission and reduce fuel consumption.
The starting characteristic of can be improved.

The present invention is not limited to the above-described embodiment, but may be implemented as follows with a part of the configuration appropriately changed without departing from the spirit of the invention. (1) In the above-described embodiment, the cooling water temperature THW is adopted as the operating state at that time, but the intake air temperature TH is also used in other cases.
A may be detected, the wall surface temperature of the intake pipe 11 near the injector 17 may be directly detected, or estimated from the operating state of the engine.

(2) In the above embodiment, the load equivalent value GN is calculated according to the intake air amount Q, etc. However, an intake pressure sensor for detecting the intake pressure is provided and the intake pressure detected by the sensor is detected. The load equivalent value GN may be calculated based on the atmospheric pressure.

(3) In the above embodiment, the automatic transmission 25, the air conditioner, etc. are exemplified as the external load, but the power load, the hydraulic drive fan, etc. are exemplified as the other loads.

(4) In the above embodiment, the fuel supply control device for the gasoline engine is explained, but it may be for the diesel engine. (5) The various maps in the above embodiment are not limited to the relationships described in the embodiment. For example, the relationship of the load increase coefficient that meets the load ratio shown in FIG. 7 does not have to be the linear relationship as shown, but may be a curvilinear relationship.

(6) In the above embodiment, the load ratio RGNS
Although TD is a value obtained by dividing the load equivalent value GN by the no-load equivalent value GNSTN, the load equivalent value GN and the no-load equivalent value GN are used.
It may be calculated based on the difference from the STN (which does not deviate from the concept of ratio).

(7) In the above embodiment, the load equivalent value G
When calculating N, use the neutral start switch 4
0 may be taken into consideration as one of the load detection means. (8) In the above embodiment, the load increase coefficient KFASED is calculated regardless of the load ratio RGNSTD. However, when the load ratio RGNSTD is almost “1.0” (corresponding to no load), A configuration may be adopted in which no increase in load is taken into consideration, assuming that there is no load at present.

(9) In the above embodiment, the load increase coefficient KFASED is added to the basic start-up increase value FASE when there is no load.
The load increase value FASED after starting is calculated by multiplying by, but the total increase value FT after starting is calculated with another increase map.
It may be added to OTAL. In this case, in order to limit the implementation to the increase only within the predetermined period from the engine start, the time from the start may be measured and the control may be ended after the predetermined period has elapsed from the start.

(10) The amount increase according to the present invention is not limited to the idling for a predetermined period from the start, and may be carried out whenever the idling state occurs. In the idling state and the cooling water temperature THW. It may be limited to only the state where the wall temperature of the intake pipe 11 is low. Alternatively, the above-mentioned increase may be performed at times other than idle. That is,
The operation may be performed during both the idle time and the non-idle time. In this case, the increase may be limited within a predetermined period from the start, and the predetermined period may be variable depending on the temperature of the engine 1 (for example, the cooling water temperature THW, the wall surface temperature of the intake pipe 11, etc.). You may

The technical idea which is not described in each claim of the claims and which can be understood from the above-mentioned embodiment will be described below together with its effect. (A) In the fuel supply control device for an internal combustion engine according to claim 1, the operating state detecting means is at least one of a water temperature sensor and an intake air temperature sensor, and the operating state corresponds to the temperature of the internal combustion engine. It is a parameter.

With the above structure, the excellent effect that the operating state can be more easily and uniquely grasped is exhibited.

[0060]

As described in detail above, according to the present invention,
In the fuel supply control device for the internal combustion engine, which is configured to increase the fuel supply amount when the external load is applied at the time of idling, since the amount can be increased according to the change in the negative pressure in the intake pipe with respect to the change in the external load, It is possible to prevent the air-fuel ratio from becoming rich or lean due to the influence of the amount of adhered walls on the inside of the intake pipe, and thus it is possible to achieve excellent idle stability. Further, unlike the conventional case, it is not necessary to increase the amount more than necessary in order to compensate for the shortage of the wall surface adhesion amount due to the external load being applied, and it is possible to improve the fuel consumption and the exhaust gas purification performance. Also plays.

[Brief description of drawings]

FIG. 1 is a conceptual configuration diagram illustrating a basic conceptual configuration of the present invention.

FIG. 2 is a schematic configuration diagram showing a fuel supply control device for an engine in an embodiment embodying the present invention.

FIG. 3 is a block diagram showing an electrical configuration of an electronic control unit (ECU) in one embodiment.

FIG. 4 is a flowchart showing a “post-start increase amount calculation routine” executed by an ECU in one embodiment.

FIG. 5 is a map showing a relationship of a no-load equivalent value with respect to a cooling water temperature, which is stored in advance in one embodiment.

FIG. 6 is a graph showing an example of changes in the load ratio with respect to time in one example.

FIG. 7 is a map in which a relationship between a load increase coefficient and a load ratio is predetermined in one embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine as an internal combustion engine, 17 ... Injector as fuel supply means, 25 ... Automatic transmission which comprises a part of external load, 31 ... Throttle sensor which comprises operating state detection means, 32 ... Operating state detection means, and Air flow meter constituting load detecting means, 33 ... intake air temperature sensor constituting operating state detecting means, 34 ... oxygen sensor constituting operating state detecting means, 35 ... water temperature sensor constituting operating state detecting means and load detecting means, Reference numeral 36 ... Revolution speed sensor constituting operating state detecting means and load detecting means, 37 ... Cylinder discrimination sensor constituting operating state detecting means, 38 ... Vehicle speed sensor constituting operating state detecting means, 39 ... Operating state detecting means Starter switch, 40 ... Neutral start switch constituting operating state detecting means and load detecting means, 51 ...憶 means, the load ratio calculation unit, increasing quantity calculating means and an ECU forming the increase correction means.

Claims (1)

[Claims] 1. A fuel supply control device for an internal combustion engine, comprising fuel supply means for supplying fuel into an intake pipe of the internal combustion engine, wherein the fuel supply amount is increased by applying an external load to the internal combustion engine during idling. A load detecting unit that detects a degree of load of the internal combustion engine that is affected by a state of application of the external load to the internal combustion engine; an operating state detecting unit that detects an operating state of the internal combustion engine; With respect to the operating state, a storage unit that stores in advance the relationship of the degree of the load of the internal combustion engine in a state in which the external load is not applied, and the operating state detected by the operating state detection unit based on the storage unit. Of the load of the internal combustion engine in a state in which the external load is not applied at all, by the load detection means for the calculation result Load ratio calculating means for calculating the ratio of the load of the internal combustion engine, and the application of the external load is determined based on the ratio calculated by the load ratio calculating means, and it is determined that the external load is added. And an increase correction means for increasing the fuel supply amount according to the ratio, and an increase correction means for correcting the fuel supply amount according to the increase amount calculated by the increase amount calculation means. A fuel supply control device for an internal combustion engine.