JP2004092465A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an air-fuel mixture from being lean by a brake operation before a power source of equipment needed for traveling is turned on. <P>SOLUTION: When a door opens, a power source control circuit 50 supplies a power source 50A to an ECU40. The ECU40 then starts, and monitors the operating condition of the brake based on a detection signal 14A of a brake switch 14. A key position is turned on to start, and when cranking starts, the ECU40 corrects an amount of fuel injection according to the number of operations of the brake. The ECU40 corrects the amount of injection fuel according to the number of operations of the brake within a predetermined period after the engine 1 is started. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device for an internal combustion engine applied to a vehicle provided with a brake booster for amplifying a brake operating force using an intake pipe pressure (negative pressure) of the internal combustion engine.
[0002]
[Prior art]
The internal combustion engine of the vehicle takes in air through a surge tank provided downstream of the intake passage, guides a mixture of air and fuel to a combustion chamber, where the fuel is burned, and then through an exhaust passage. Exhaust. An engine control unit (hereinafter, referred to as an ECU) functions as a center for controlling fuel combustion, and determines a fuel injection amount such that an air-fuel ratio, which is a mixture ratio of air and fuel, matches a target value.
[0003]
More specifically, the ECU estimates the amount of air flowing into the combustion chamber based on the amount of air measured by an air flow meter provided in the intake passage, and determines the fuel injection amount according to the estimated amount of air. I have decided.
[0004]
In a vehicle, a brake booster is generally provided to assist a brake operating force. The brake booster is connected to a surge tank via a negative pressure passage, and operates using a difference between an intake negative pressure of the internal combustion engine and atmospheric pressure.
[0005]
In a vehicle equipped with such a brake booster, when the driver operates the brake, air flows from the brake booster into the surge tank via the negative pressure passage. Therefore, when the driver operates the brake, the amount of air flowing into the combustion chamber increases.
[0006]
However, since the air flow meter is provided in the intake passage, the ECU cannot determine the fuel injection amount in consideration of the amount of air flowing from the brake booster. As a result, when the driver operates the brake, the air-fuel ratio of the air-fuel mixture, which had been adjusted to an appropriate value (theoretical air-fuel ratio) in the internal combustion engine, temporarily changes to the target value by adding air from the brake booster. Leaner.
[0007]
Therefore, various techniques for solving such a problem have been proposed. For example, Japanese Unexamined Utility Model Publication No. 2-4944 discloses a technique for increasing the fuel injection amount when a brake is activated.
[0008]
[Problems to be solved by the invention]
By the way, the key position of a cylinder lock mounted on a vehicle generally has four stages of off, ACC on, main on, and start. The state in which the key of the vehicle is inserted into the cylinder lock is an off state. When the key is rotated one step clockwise from the key position, the ACC state is turned on. In this state, the power of the attached devices such as the car stereo and the air conditioner is turned on. When the key is rotated one step clockwise from the ACC-on key position, the main-on state is established. In this state, the ECU is activated and the power required for the devices required for traveling is turned on. Further, when the key is rotated one step clockwise from the main-on key position, a start state is established, the starter motor is started, and the internal combustion engine is started through a cranking operation. Therefore, after the ECU is started and signals from various sensors connected thereto can be monitored after the key position is turned on.
[0009]
However, a driver in the vehicle may operate the brakes before inserting the key into the cylinder lock. For example, when the driver gets into the vehicle for the first time, the driver adjusts the seat position so that the brake and the accelerator can be easily operated. In this case, the driver often depresses the brake while actually shifting the seat position to find a position where the driver can easily operate the brake.
[0010]
When such a brake is repeatedly operated, the negative pressure in the brake booster gradually approaches the atmospheric pressure. Then, when the internal combustion engine is started in such a state, air flows from the brake booster into the surge tank, the air amount in the combustion chamber increases, and the air-fuel ratio becomes lean.
[0011]
The ECU determines the fuel injection amount. However, since the ECU is activated after the key position is turned on as described above, even if the brake is operated before that, the ECU takes into account that fact. Therefore, the fuel injection amount cannot be controlled.
[0012]
The present invention has been made in view of the above-described circumstances, and monitors the state of a brake before power is supplied to a device required for operation of an internal combustion engine, and determines a fuel injection amount during a start period of the internal combustion engine. It is an object of the present invention to provide a device for controlling the pressure.
[0013]
[Means for Solving the Problems]
The control device for an internal combustion engine according to the present invention includes a brake booster that communicates with an intake passage of the internal combustion engine and assists a brake operating force, and supplies power to devices necessary for operating the internal combustion engine in a procedure for starting the internal combustion engine. Detecting means for outputting a detection signal corresponding to an operation state of the brake, wherein the detection means outputs a detection signal corresponding to an operation state of the brake; A fuel injection control means is provided for monitoring the detection signal one stage before, and for controlling fuel injection in consideration of a monitoring result during a start-up period of the internal combustion engine (claim 1).
[0014]
According to the present invention, it is possible to monitor the operation state of the brake before turning on the power to the devices necessary for operating the internal combustion engine, and control the fuel injection in consideration of the monitoring result. Therefore, even if the brake is operated before the first stage and air flows into the intake passage from the brake booster during the starting period and the intake negative pressure fluctuates, it is possible to correct the fluctuation in accordance with the operation state of the brake. As a result, the air-fuel ratio can be made to match the target value. As a result, fuel can be ideally burned during the starting period, and harmful emissions can be significantly reduced.
[0015]
The operation of the internal combustion engine is performed by igniting a mixture of fuel and air in a combustion chamber. This operation requires preparation for operation of the internal combustion engine, such as generating a high voltage used for ignition or supplying power to a sensor required for combustion control. Therefore, power is supplied to the devices necessary for the operation of the internal combustion engine in advance before the internal combustion engine is started, whereby preparations for starting are started. The devices necessary for the operation of the internal combustion engine include, for example, devices required for ignition such as an igniter, or various sensors such as an oxygen sensor and an air flow meter.
[0016]
Further, it is preferable that the fuel injection control means controls fuel injection in consideration of the monitoring result during a predetermined period following a start period of the internal combustion engine (claim 2). If the brake is operated before the start of the internal combustion engine, air flows from the brake booster into the intake passage during the start period, because the internal pressure of the brake booster approaches the atmospheric pressure. The internal pressure of the brake booster gradually returns to a steady state as the internal combustion engine starts and repeats intake and exhaust. Therefore, by performing the fuel injection control in consideration of the operation state of the brake during a predetermined period following the start period of the internal combustion engine, the air-fuel ratio can be made equal to the target value even after the start, and the fuel can be ideally controlled. Burning can greatly reduce harmful emissions.
[0017]
Here, it is preferable that the fuel injection means monitors the number of times of operation of the brake based on the detection signal, and controls fuel injection in consideration of the number of times of operation of the brake (claim 3).
[0018]
Further, the fuel injection means may monitor the operation time of the brake based on the detection signal and control the fuel injection in consideration of the operation time of the brake.
[0019]
Further, the fuel injection means may monitor the operation force of the brake based on the detection signal and control the fuel injection in consideration of the operation force of the brake (claim 5). In this case, the detection means corresponds to, for example, a pressure sensor provided in a brake booster.
[0020]
Next, the control device for an internal combustion engine described above includes a detection unit that detects a driver's entry into the vehicle, and the fuel injection control unit detects the driver's entry by the detection unit. It is preferable to start monitoring the detection signal (claim 6). According to the present invention, when the driver gets into the vehicle, monitoring of the operation state of the brake is started, so that the amount of air flowing into the internal combustion engine from the brake booster is accurately estimated, and the amount of fuel supplied during the start-up period and after the start-up period Injection can be controlled accurately.
[0021]
More specifically, it is preferable that the detecting means includes a sensor that detects that a door of the vehicle is opened, and detects the boarding of the operator in consideration of a detection result of the sensor. 7). Further, the detection means may include a sensor for detecting that the locking device of the vehicle is in an unlocked state, and may detect the entry of the operator in consideration of the detection result of the sensor (claim Item 8). Further, the detection means may include a sensor for detecting a seat in a driver's seat, and may detect the boarding of the operator in consideration of a detection result of the sensor (claim 9).
[0022]
In the control device for an internal combustion engine described above, it is preferable that the fuel injection control means continues the fuel injection control in consideration of the monitoring result until the intake negative pressure becomes a steady state (claim 10). Fuel injection control taking into account the brake operation state aims to prevent the mixture ratio of air and fuel from becoming lean due to the intake negative pressure deviating from the steady state. This is because it is preferable to continue the fuel injection control in consideration of the monitoring result until becomes a steady state.
[0023]
Another control device for an internal combustion engine according to the present invention is applied to a vehicle including a brake booster which is communicated with an intake passage of the internal combustion engine and assists a brake operating force, and corresponds to an operation state of the brake. Detecting means for outputting a detection signal; detecting a driver's entry into the vehicle to start monitoring the detection signal; and controlling fuel injection in consideration of a monitoring result during a starting period of the internal combustion engine. Fuel injection control means (claim 11). According to the present invention, when the driver gets into the vehicle, the fuel injection control means starts monitoring the operation state of the brake. Since the brake is operated after the driver gets into the vehicle, the operation state of the brake before the start of the internal combustion engine can be reflected in the fuel injection control in the starting period.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a schematic configuration of a fuel injection control device. As shown in FIG. 1, a vehicle is equipped with a multi-cylinder gasoline engine (hereinafter simply referred to as an engine) 1 as an internal combustion engine. The engine body 10, which constitutes a main part of the engine 1, has a combustion chamber (not shown) for each cylinder, and an intake passage 2 and an exhaust passage 3 communicate with these combustion chambers.
[0025]
In the intake passage 2, an air cleaner 4, a throttle valve 5, a surge tank 6, and an intake manifold 7 are sequentially arranged from the upstream side toward the engine body 10. The outside air is taken into the combustion chamber via each of these elements 4 to 7. The throttle valve 5 is driven in conjunction with a depression operation of an accelerator pedal (not shown), and the drive adjusts the amount of intake air flowing through the intake passage 2. Further, the surge tank 6 smoothes the pulsation of the intake air.
[0026]
The intake manifold 7 is provided with fuel injection valves 8A, 8B, 8C, 8D for injecting fuel into the combustion chamber of each cylinder. Then, a mixture of the fuel injected from each of the fuel injection valves 8A to 8D and the outside air introduced into the intake passage 2 is introduced into each combustion chamber. A spark plug (not shown) is attached to the engine body 10 to ignite the air-fuel mixture introduced into each combustion chamber. Each ignition plug is driven based on an ignition signal distributed by a distributor (not shown). The distributor distributes the high voltage output from the igniter (not shown) to the ignition plug in synchronization with the rotation angle of the crankshaft of the engine body 10. Then, the air-fuel mixture introduced into the combustion chamber is burned by the ignition of the spark plug. This combustion generates the driving force of the engine 1. The combustion gas thus generated in the combustion chamber is discharged to the outside via the exhaust passage 3.
[0027]
The engine 1 is provided with an air flow meter 11, a water temperature sensor 12, a throttle sensor 13, and the like. The air flow meter 11 is provided downstream of the air cleaner 4 and detects the amount of air flowing through the intake passage 2 (the amount of intake air). As the air flow meter 11, for example, a vane type, a hot wire type, or a Kalman type can be used.
[0028]
The water temperature sensor 12 is a sensor that detects the temperature of the cooling water of the engine 1 and is disposed on the engine body 10. The throttle sensor 13 is provided near the throttle valve 5 and detects the opening thereof.
[0029]
The vehicle is provided with a hydraulic foot brake (not shown) for stopping or decelerating a running vehicle or preventing a stopped vehicle from running. The brake applies a pressure to the brake fluid in the master cylinder 21 in response to a depression operation of the brake pedal 20 by a driver, and operates a brake shoe or the like to generate a braking force. A brake switch 14 is provided near the brake pedal 20. The brake switch 14 is normally in an off state, and outputs a detection signal 14A that becomes high level (active) only when the driver depresses the brake pedal 20 by a predetermined amount or more.
[0030]
Further, a brake booster 30 is provided between the master cylinder 21 and the brake pedal 20 in order to reduce an operation force when the brake pedal 20 is depressed. The brake booster 30 is partitioned by a power piston 31 into a constant pressure chamber 32 and a variable pressure chamber 33. The constant pressure chamber 32 and the surge tank 6 are connected by a negative pressure passage 34, and the intake pipe pressure (negative pressure) in the surge tank 6 generated during operation of the engine 1 is reduced through the negative pressure passage 34. 32. A check valve 35 is provided in the middle of the negative pressure passage 34. The check valve 35 regulates the direction of the air flow in the negative pressure passage 34 and allows only the air flow from the constant pressure chamber 32 to the surge tank 6.
[0031]
An atmosphere passage 36 extends from the transformation chamber 33, and the end of the passage 36 is open to the atmosphere. Then, the atmosphere can be introduced into the transformation chamber 33 through the atmosphere passage 36. Further, the power piston 31 is provided with a communication path (not shown) that allows the constant pressure chamber 32 and the variable pressure chamber 33 to communicate with each other.
[0032]
The brake booster 30 has a switching mechanism (not shown) that switches between a communication state between the constant-pressure chamber 32 and the variable-pressure chamber 33 and a communication state between the inside and the outside of the variable-pressure chamber 33 in accordance with the depression operation of the brake pedal 20. Z) is provided. When the brake pedal 20 is not depressed, the switching mechanism allows communication between the constant-pressure chamber 32 and the variable-pressure chamber 33 and shuts off air introduction to the variable-pressure chamber 33. In this state, the intake pipe pressure in the surge tank 6 acts on the constant pressure chamber 32 and the variable pressure chamber 33, and the pressure in both chambers 32 and 33 becomes substantially the same.
[0033]
When the brake pedal 20 is depressed, the switching mechanism cuts off the communication between the constant pressure chamber 32 and the variable pressure chamber 33 and allows the introduction of the atmosphere into the variable pressure chamber 33. In this state, a negative pressure acts on the constant pressure chamber 32 and an atmospheric pressure acts on the variable pressure chamber 33. As a result, a pressure difference is generated on both sides of the power piston 31, and a force based on this pressure difference is transmitted to the master cylinder 21 in addition to the depressing force applied to the brake pedal 20. With this addition, the depression force of the brake pedal 20 is reduced.
[0034]
In the configuration of the brake booster 30 described above, the air that has flowed into the variable pressure chamber 33 when the brake pedal 20 is depressed flows into the constant pressure chamber 32 from the variable pressure chamber 33 when the brake pedal 20 is returned. This is the same when the brake pedal 20 is depressed while the engine 1 is stopped. Therefore, if the brake pedal 20 is repeatedly depressed while the engine 1 is stopped, the pressure in the constant-pressure chamber 32 gradually approaches the atmospheric pressure. That is, the pressure in the constant-pressure chamber 32 changes according to the operation state of the brake pedal 20. The amount of air flowing into the surge tank 6 from the brake booster 30 via the negative pressure passage is determined by the pressure of the constant pressure chamber 32 during and after the start of the engine 1. That is, if the operation state of the brake pedal 20 is monitored, it is possible to estimate the amount of inflowing air.
[0035]
In order to monitor the brake pedal 20 when the engine 1 is stopped, the ECU 40 needs to operate in such a state. Therefore, in the present embodiment, the entry of a person into the vehicle is detected by various sensors, and the ECU 40 is activated based on the detection result.
[0036]
The power supply control circuit 50 controls the timing of supplying power to various devices of the vehicle. The power control circuit 50 is connected with a door sensor 51, a key sensor 52, and the like. The door sensor 51 generates a detection signal 51A that goes low when the door is closed and goes high when the door is opened.
[0037]
Further, the key sensor 52 outputs first, second, and third detection signals 52A, 52B, and 52C whose logical levels change according to the key position of the cylinder lock. There are four key positions: off, ACC on, main on, and start on. First, when the key position is off, the first to third detection signals 52A to 52C become low level. Next, when the key position is ACC on, the first detection signal 52A goes high while the second and third detection signals 52B and 52C go low. When the key position is main-on, the first and second detection signals 52A and 52B are at a high level, while the third detection signal 52C is at a low level. Further, when the key position is start-on, the first to third detection signals 52A to 52C become high level.
[0038]
The power supply control circuit 50 of this example supplies power to a device such as a car stereo or an air conditioner while the first detection signal 52A is at a high level, and is necessary for ignition of an igniter or the like while the second detection signal 52B is at a high level. Power to the necessary devices or devices necessary for the operation of the engine 1, such as the oxygen sensor and the air flow meter 11, and further supplies power to the starter motor while the third detection signal 52C is at a high level.
[0039]
Further, the power supply control circuit 50 supplies the power supply 50A to the ECU 40 during a period from when the detection signal 51A of the door sensor 51 becomes high level to when the second detection signal 52B transitions from high level to low level. The ECU 40 is activated by power supply from the power supply 50A. Thus, the ECU 40 is started before power is supplied to devices required for the operation of the engine 1 and can monitor the state of the brake.
[0040]
Next, the ECU 40 includes a CPU, a ROM, a RAM, a backup RAM, an input / output interface, and the like. In the ROM, a control program and initial data necessary for executing arithmetic processing by the CPU are stored in advance. The RAM functions as a work area of the CPU, and temporarily stores a calculation result. The backup RAM is backed up by a lithium battery or the like so as to retain various data even after the power is turned off.
[0041]
FIG. 2 is a flowchart showing the operation of the ECU 40. When the door is opened, power supply 50A is supplied from power supply control circuit 50 to ECU 40, and ECU 40 is activated. The ECU 40 starts the brake state monitoring process immediately after the startup (step S1). In the monitoring processing, the number N of brake operations performed by the driver is counted (step S2). More specifically, the CPU of the ECU 40 counts the number of times that the detection signal 14 of the brake switch 14 rises from a low level to a high level, and stores the counted value in the RAM as the number N of brake operations.
[0042]
Next, the ECU 40 determines whether or not cranking has been started (step S3), and repeats the processing of steps S2 and S3 until cranking is started. Specifically, when the third detection signal 52C output from the key sensor 52 transitions from a low level to a high level, it is determined that cranking has started. In this case, the key position of the cylinder lock is in a start-on state, and the starter motor starts.
[0043]
When cranking is started, the ECU 40 starts fuel injection control in a starting period (step S4). In the fuel injection control in the starting period, the ECU 40 determines the injection amount in consideration of the number of brake operations N.
[0044]
If the starting period injection amount is etaust, the starting period basic injection value is etaustb, the engine speed correction coefficient is eknest, the battery voltage correction coefficient is ekbst, and the corrected injection amount according to the brake operation state is ekbrkst, The injection amount etaust is given by Expression 1 shown below. Note that the starting period injection amount etaust, the starting period basic injection value etaustb, and the corrected injection amount ekbrkst are given as times during which fuel is injected from the fuel injection valves 8A to 8D.
etaust = etaustb * eknest * ekbst + ekbrkst Equation 1
[0045]
Here, the starting period basic injection value etaustb is obtained by referring to an injection amount map that stores the engine water temperature value and the starting period basic injection value etaustb in association with each other. This injection amount map is stored in the ROM. The CPU accesses the injection amount map based on the engine water temperature value obtained by A / D converting the output signal of the water temperature sensor 12, and generates the starting period basic injection value etaustb.
[0046]
Further, the corrected injection amount ekbrkst is obtained by referring to the starting period correction amount map stored in association with the number of times of the brake operation and the corrected injection amount ekbrkst. FIG. 3 shows an example of the stored contents of the starting period correction amount map. In this example, the correction injection amount ekbrkst increases as the number N of brake operations increases.
[0047]
If the number of times the brake is operated before the start of the engine 1 increases, the amount of air flowing into the surge tank 6 from the brake booster 30 increases, so that the air-fuel mixture during the starting period becomes lean. In the present embodiment, the ECU 40 is started to monitor the operation state of the brake before the power is turned on to the devices necessary for the operation of the engine 1, and the starting injection amount etaust in consideration of the brake operation state is considered. Therefore, in the starting period of the engine 1, the air-fuel ratio can be made closer to the target value.
[0048]
Next, the ECU 40 determines whether or not the start of the engine 1 has been completed (step S5). Completion of the start of the engine is determined by the fact that the engine speed reaches a predetermined speed (preferably 400 rpm), and fuel injection control in the starting period is performed until the engine speed reaches the predetermined speed. When the ECU 40 detects that the start of the engine 1 is completed, the ECU 40 performs fuel injection control after the start (step S6). Also in the fuel injection control after the start, control is performed in consideration of the operation state of the brake before the start of the engine 1. The reason is that the negative pressure of the intake air in the surge tank 6 gradually converges to a steady state negative pressure as the engine 1 starts and repeats the intake and exhaust. That is, when the engine 1 starts, the pressure does not immediately become the steady state negative pressure, but gradually changes from the pressure before the engine 1 starts to the steady state negative pressure. Then, air flows from the brake booster 30 into the surge tank 6 while the intake negative pressure changes to a steady state. Therefore, even in a predetermined period following the start period, the fuel injection control is performed in consideration of the operation state of the brake before the start.
[0049]
In the fuel injection control after the start, the ECU 40 determines the fuel injection amount according to the following Expressions 2 and 3.
etauout = etaub * ekrichx Equation 2
ekrichx = 1 + efase1 + efase2 + efwl + efbrk Equation 3
efbrk = efbrkb + efbrkdec Equation 4
(Attenuation is every 65ms)
[0050]
However, the post-start injection amount is etaout, the post-start basic injection value is etaub, the injection amount correction coefficient is ekrichk, the post-start increase 1 (slow attenuation) is efase1, the post-start increase 2 (sudden decay) is efase2, and the basic warm-up increase. The coefficient is efwl, and the brake correction coefficient is efbrk.
[0051]
Here, the post-startup basic injection value etaub is calculated based on the intake air amount. Further, the brake correction coefficient efbrk is obtained by referring to a post-start correction coefficient map in which the number of brake operations N, the basic coefficient efbrkb, and the damping coefficient efbrkdec are stored in association with each other. FIG. 4 shows an example of the stored contents of the post-start correction coefficient map. This post-startup correction coefficient map is stored in the ROM. The CPU accesses the post-start correction coefficient map based on the number of brake operations, reads the basic coefficient efbrkb and the damping coefficient efbrkdec, and calculates the brake correction coefficient efbrk.
[0052]
Next, the ECU 40 determines whether or not the termination condition has been satisfied (step S7). The termination condition is determined so that a point in time at which the brake operation before starting the engine 1 does not affect the injection amount can be determined. In other words, the end condition is determined so that the time point at which the intake negative pressure reaches the steady state pressure can be determined. Specifically, an elapsed time after the start or an integrated air amount after the start may be set as the termination condition.
[0053]
If the termination condition is satisfied, the ECU 40 starts the air-fuel ratio feedback control (step S8). In the air-fuel ratio feedback control, the injection amount is not corrected based on the number of brake operations N, and the intake amount and the injection amount are feedback-controlled.
[0054]
Thereafter, the ECU 40 determines whether or not the power supply has been stopped, and continues the air-fuel ratio feedback control until the power supply is stopped (step S9).
[0055]
Next, the operation of the ECU 40 will be specifically described with reference to a timing chart shown in FIG. At time t1, when the driver unlocks the door, the detection signal 51A of the door sensor 51 goes high. Then, the power supply control circuit 50 starts supplying the power supply 50A in synchronization with the rising edge of the detection signal 51A. That is, it is detected that the driver gets into the vehicle by unlocking the door, and the ECU 40 starts monitoring the operation state of the brake from the time of getting on.
[0056]
Then, at time t2, time t3, and time t4, when the driver depresses the brake pedal 20, the detection signal 14A of the brake switch 14 goes high only during a period corresponding to the depression. The ECU 40 counts rising edges of the detection signal 14A to generate the number N of brake operations. Therefore, as shown in the figure, the number of brake operations changes as N = 0 → N = 1 (time t2) → N = 2 (time t3) → N = 3 (time t4).
[0057]
Next, at time t5, when the driver operates the key to turn on the key position ACC, the first detection signal 52A changes from the low level to the high level, and power is supplied to an attached device such as a car stereo. . Further, when the key position is turned on at time t6, the second detection signal 52B changes from the low level to the high level, and power is supplied to devices necessary for the operation of the engine 1 to prepare for the start of the engine 1. Be started.
[0058]
Next, at time t7, when the key position is turned on, the starter motor is driven, and the ECU 40 executes the fuel injection control in the starting period. At this time, the starting period correction amount map shown in FIG. 3 is referred to. In this example, since the number N of brake operations is "3", 5 ms is obtained as the corrected injection amount ekbrkst. Thereby, the injection amount is corrected so that the air-fuel ratio becomes an appropriate value.
[0059]
Then, at the time t8, when the cranking is completed and the engine 1 is started, the key position is returned to the main-on state. At this time, the third detection signal 52C transitions from a high level to a low level. The ECU 40 ends the fuel injection control in the starting period and starts the fuel injection control after the starting. At this time, a post-start correction coefficient map shown in FIG. 4 is referred to. In this example, since the number N of brake operations is “3”, 0.5 is obtained as the basic coefficient efbrkb and 0.99 is obtained as the damping coefficient efbrkdec. Thereby, the injection amount is corrected so that the air-fuel ratio becomes an appropriate value.
[0060]
Here, assuming that the end condition of the injection amount correction based on the number of brake operations N is that the elapsed time from the start of the engine 1 has reached Tx, at time t9 when the time Tx has elapsed from time t8, the ECU 40 Then, the fuel injection control after the start is ended, and the air-fuel ratio feedback control is started.
[0061]
Further, at time t10, when the key position is returned to the ACC ON state, the second detection signal 52B changes from the high level to the low level. Then, the power supply control circuit 50 stops the power supply 50A supplied to the ECU 40. As a result, the operation of the ECU 40 is stopped.
[0062]
As described above, according to the present embodiment, the door sensor 51 detects that the driver has entered the vehicle, activates the ECU 40, and uses the brake switch 14 to set the brake state before the engine 1 starts. Is detected, and the fuel injection amount is determined based on the detection result. Therefore, even if the intake negative pressure changes due to the brake operation, this can be corrected. As a result, the air-fuel ratio in the starting period and after the starting can be matched with the target value, and harmful emissions can be reduced.
[0063]
Note that the present invention is not limited to the above-described embodiment, and for example, the following modifications are possible.
[0064]
In the above-described embodiment, the ECU 40 is activated by detecting that the driver has entered the vehicle using the door sensor 51. However, the present invention is not limited to this. Using a remote control door switch, door key, smart key to detect, or a seating sensor provided in the driver's seat to detect the driver's seat or a vibration sensor to detect vibration, etc. Good.
[0065]
Further, the activation of the ECU 40 may be started at a timing when the driver may operate the brake before the engine 1 is started. In this regard, when the driver operates the keys to turn on the key position, the power necessary for traveling is turned on and the preparation for starting is started. It is preferable to monitor the condition.
[0066]
Further, in the above-described embodiment, the number of times of the brake operation N is counted and the state of the brake is detected. However, in consideration of the integrated time of the brake operation or the strength of the brake operation, the starting period and the time after the start are considered. The fuel injection amount may be controlled. The integrated time of the brake operation may be obtained by integrating the time when the detection signal 14A of the brake switch 14 is at the high level. When the integration time becomes longer, the internal pressure of the brake booster 30 approaches the atmospheric pressure. Therefore, the ECU 40 may control the fuel injection so that the injection amount becomes larger as the integration time becomes longer. The strength of the brake operation may be detected by arranging a pressure sensor inside the brake booster 30 and based on an output signal from the pressure sensor. In this case, the ECU 40 may control the fuel injection so that the injection amount increases as the internal pressure increases. Further, the amount of air flowing from the brake booster 30 into the surge tank 6 is estimated by appropriately combining the number N of times of the brake operation, the cumulative time of the brake operation, and the strength of the brake operation, and the injection amount is determined according to the estimated air amount. The fuel injection may be controlled as described above.
[0067]
Further, in the above-described embodiment, the entire ECU 40 is activated by supplying the power supply 50A to the ECU 40. However, the present invention is not limited to this, and only the configuration of the ECU 40 necessary for monitoring the brake state is provided. Alternatively, the ECU 40 may be started before power is supplied to devices necessary for the operation of the engine 1, and the entire ECU 40 may be started when the key position is turned on.
[0068]
【The invention's effect】
As described above, according to the control apparatus for an internal combustion engine according to the present invention, the state of the brake is monitored before power is supplied to devices required for operating the internal combustion engine, and the fuel Therefore, even if the brake is operated while the internal combustion engine is stopped and the internal pressure of the brake booster fluctuates, it is possible to control the fuel injection in consideration of the fluctuation.
[Brief description of the drawings]
FIG. 1 is a block diagram of a fuel injection amount control device according to an embodiment of the present invention.
FIG. 2 is a flowchart for explaining the operation of an ECU used in the device.
FIG. 3 is an explanatory diagram showing stored contents of a starting period correction amount map used for fuel injection control in a starting period.
FIG. 4 is an explanatory diagram showing stored contents of a post-start correction coefficient map used for post-start fuel injection control.
FIG. 5 is a timing chart for specifically explaining the operation of the ECU 40.
[Explanation of symbols]
1 engine
6 surge tank
7 Intake manifold
14 Brake switch
30 Brake booster
34 Negative pressure passage
40 ECU
51 Door sensor

Claims (11)

A brake booster that is in communication with the intake passage of the internal combustion engine and assists the operation force of the brake; A control device for the internal combustion engine applied to the vehicle, which is executed separately from the second stage.
Detecting means for outputting a detection signal corresponding to the operation state of the brake;
A control device for an internal combustion engine, comprising: a fuel injection control unit that monitors the detection signal before the first stage and controls fuel injection in consideration of a monitoring result during a start period of the internal combustion engine. 2. The control device for an internal combustion engine according to claim 1, wherein the fuel injection control unit controls fuel injection in a predetermined period following a start period of the internal combustion engine in consideration of the monitoring result. 3. 3. The internal combustion engine according to claim 1, wherein the fuel injection unit monitors the number of times of operation of the brake based on the detection signal, and controls fuel injection in consideration of the number of times of operation of the brake. 4. Engine control device. The fuel injection means monitors the operation time of the brake based on the detection signal, and controls the fuel injection in consideration of the operation time of the brake. 2. The control device for an internal combustion engine according to claim 1. The fuel injection means monitors the operation force of the brake based on the detection signal, and controls the fuel injection in consideration of the operation force of the brake. 2. The control device for an internal combustion engine according to claim 1. Equipped with detection means for detecting the driver getting into the vehicle,
The internal combustion engine according to any one of claims 1 to 5, wherein the fuel injection control means starts monitoring the detection signal when the detection means detects that the driver has entered the vehicle. Engine control device. 7. The internal combustion engine according to claim 6, wherein the detection unit includes a sensor that detects that a door of the vehicle is opened, and detects the entry of the operator in consideration of a detection result of the sensor. Engine control device. The said detection means includes a sensor which detects that the locking device of the said vehicle was in an unlocked state, and detects the boarding of the said operator in consideration of the detection result of the said sensor. 7. The control device for an internal combustion engine according to 6. 7. The internal combustion engine control according to claim 6, wherein the detection unit includes a sensor that detects a seat in a driver's seat, and detects the boarding of the operator in consideration of a detection result of the sensor. apparatus. 10. The control device for an internal combustion engine according to claim 1, wherein the fuel injection control means continues the fuel injection control in consideration of the monitoring result until the intake negative pressure becomes a steady state. In a control device for an internal combustion engine applied to a vehicle including a brake booster which is communicated with an intake passage of the internal combustion engine and assists a brake operating force,
Detecting means for outputting a detection signal corresponding to the operation state of the brake;
A fuel injection control means for detecting a driver's entry into the vehicle to start monitoring the detection signal, and controlling fuel injection in consideration of a monitoring result during a starting period of the internal combustion engine. Engine control device.

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