JP2000291465A - Fuel injection controller of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent an exhaust system from being overheated without causing unnecessary increase in fuel by taking into account the operation state of an engine and the delay of the temperature rise due to the heat capacity of the exhaust system. SOLUTION: In a case where at least one of conditions of high load state or high rotation state is established and a set time TDILLY passes after the exhaust temperature decrease correction is released, an exhaust temperature decrease correction delay time MDILLY is set (S109), an exhaust temperature decrease correction factor KRICH is set to zero (S107), until the elapsed time after the condition is established reaches the exhaust temperature decrease correction delay time MDILLY, and the fuel increase by the exhaust temperature decrease correction is not performed. When the elapsed time reaches the exhaust temperature decrease correction delay time MDILLY, the exhaust temperature decrease correction factor KRICH is set (S114), on the basis of an engine speed Ne and a basic fuel injection pulse length Tp, the fuel increase is performed by using the exhaust temperature decrease correction factor KRICH, the rise of the exhaust gas temperature is restrained with the air fuel ratio richer than the output air fuel ratio, and overheating of an exhaust system is prevented in advance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine fuel for increasing the fuel injection amount during high-load operation or high-speed operation of the engine to lower the exhaust gas temperature and to prevent damage due to overheating of exhaust system components such as a catalyst. The present invention relates to an injection control device.

[0002]

2. Description of the Related Art In general, in combustion injection control of an engine, in an operating region where the temperature of exhaust gas rises, the amount of fuel injection is controlled to prevent exhaust system components such as a catalyst for purifying exhaust gas from overheating and deteriorating. Although the exhaust temperature is lowered by increasing the amount, the temperature rise of the exhaust system components is delayed with respect to the increase of the exhaust temperature because the heat capacity of the exhaust system is large, and during that time, unnecessary fuel increase is performed. There is a problem in that it is disadvantageous in fuel consumption measures.

For this reason, Japanese Patent Application Laid-Open No. 63-61735 discloses that when the engine load becomes high, the fuel supply amount is reduced if the duration of the low load operation state before the high load is shorter than the target time. If the duration of the low-load operation state before the load becomes high is longer than the target time, the fuel supply amount is increased when the exhaust temperature exceeds the target exhaust temperature. Thus, a technique is disclosed in which the fuel is not increased simply by shifting to the high load operation state after the low load operation state continues for a long time.

[0004]

However, in the above-mentioned prior art, when a high load operation state is entered after a long low load operation state, the fuel is increased after the exhaust gas temperature exceeds the target temperature. However, in the operating range where the exhaust gas temperature rises rapidly during high load operation or high rotation operation, etc., even if the fuel is increased after the exhaust gas temperature exceeds the target temperature, the temperature immediately rises due to the delay due to the heat capacity of the exhaust system. Not drop,
There is a risk of overheating.

The present invention has been made in view of the above circumstances, and takes into consideration the operating state of the engine and the delay in temperature rise due to the heat capacity of the exhaust system, and reliably prevents overheating of the exhaust system without inducing unnecessary fuel increase. It is an object of the present invention to provide an engine fuel injection control device capable of preventing the fuel injection.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, it is determined whether or not an engine operation state corresponds to at least one of a high load state and a high rotation state. An engine operating state determining unit configured to determine whether the engine operating state corresponds to at least one of a high load state and a high rotation state, and perform an exhaust temperature reduction correction to prevent exhaust system heating. Delay time setting means for setting the delay time based on the engine operating state, and when the elapsed time after the engine operating state has at least one of the high load state and the high rotation state has reached the delay time, Fuel injection control means for increasing the fuel injection amount by the exhaust gas temperature reduction correction.

According to a second aspect of the present invention, in the first aspect of the invention, the fuel injection control means sets the engine operating state to a high level before the elapsed time after the cancellation of the exhaust gas temperature reduction correction reaches the set time. When at least one of the load state and the high rotation state is attained, the fuel injection amount is increased by the exhaust temperature reduction correction without waiting for the delay time to elapse.

According to a third aspect of the present invention, in the first or second aspect of the invention, the delay time setting means sets the delay time based on an engine speed and an engine load. I do.

That is, according to the first aspect of the present invention, it is determined whether the engine operating state corresponds to at least one of a high load state and a high rotation state, and at least one of the high load state and the high rotation state is determined. In one of the states, when the delay time set based on the engine operating state has elapsed, exhaust temperature reduction correction is executed to prevent the exhaust system from heating, and the fuel injection amount is increased.

In this case, the engine operation state becomes at least one of a high load state and a high rotation state before the elapsed time after canceling the exhaust gas temperature reduction correction reaches the set time. Then, the fuel injection amount is increased by the exhaust gas temperature reduction correction without waiting for the delay time to elapse. The delay time is set based on the engine speed and the engine load.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 relate to an embodiment of the present invention, FIG. 1 is a flowchart of a fuel injection amount setting routine, FIG. 2 is an explanatory diagram of each correction map, FIG. 3 is an overall schematic diagram of an engine, and FIG. FIG. 3 is a circuit configuration diagram of a control system.

First, the overall structure of the engine will be described with reference to FIG. In FIG. 1, reference numeral 1 denotes an engine, which in this embodiment is a horizontally opposed four-cylinder gasoline engine. Cylinder heads 2 are provided in both left and right banks of a cylinder block 1a of the engine 1, respectively, and each cylinder head 2 is formed with an intake port 2a and an exhaust port 2b.

As an intake system of the engine 1, an intake manifold 3 communicates with each intake port 2a of a cylinder head 2, and the intake manifold 3 communicates with an accelerator pedal through an air chamber 4 in which intake passages of respective cylinders are gathered. A throttle chamber 5 in which a throttle valve 5a interlocked with the throttle chamber 5 is communicated. Further, an air cleaner 7 is attached to the upstream side of the throttle chamber 5 via an intake pipe 6, and the air cleaner 7 is connected to the air intake chamber 8.

The intake pipe 6 is connected to a bypass passage 9 for bypassing the throttle valve 5a. The bypass passage 9 adjusts the amount of bypass air flowing through the bypass passage 9 at idle according to the valve opening. Speed control valve (ISC valve) that controls the idle speed with a valve
10 are interposed.

An injector 11 is disposed immediately upstream of the intake port 2 a of each cylinder of the intake manifold 3, and communicates with a fuel tank 13 via a fuel supply path 12. The fuel tank 13 is provided with an in-tank type fuel pump 14, and the fuel from the fuel pump 14 is pumped to the injector 11 and the pressure regulator 16 via a fuel filter 15 interposed in the fuel supply path 12. Then, the pressure is returned from the pressure regulator 16 to the fuel tank 13 and the fuel pressure to the injector 11 is adjusted to a predetermined pressure.

An ignition plug 17 for exposing a discharge electrode at the tip to the combustion chamber is attached to each cylinder of the cylinder head 2, and an ignition coil 18 containing an igniter 19 is connected to the ignition plug 17. .

On the other hand, as an exhaust system of the engine 1, an exhaust pipe 21 is communicated with a collection portion of an exhaust manifold 20 which communicates with each exhaust port 2b of the cylinder head 2, and a catalytic converter 22 is interposed in the exhaust pipe 21. To the muffler 23.

Here, sensors for detecting the operating state of the engine will be described. Immediately downstream of the air cleaner 7 of the intake pipe 6, a thermal intake air amount sensor 24 using a hot wire or a hot film is interposed, and a throttle valve 5 provided in the throttle chamber 5 is provided.
A throttle opening sensor 25 for detecting the opening of the throttle valve 5a is connected to a.

The cylinder block 1a of the engine 1
A knock water sensor 27 is attached to a cooling water passage 27 which communicates the left and right banks of the cylinder block 1a. Further, an O2 sensor 29 is disposed upstream of the catalytic converter 22 as an example of an air-fuel ratio sensor.

The crankshaft 30 of the engine 1
A crank angle sensor 32 for detecting a crank angle is provided on an outer periphery of a crank rotor 31 which is axially mounted on the cam rotor 33. A cylinder discriminating sensor 35 for discriminating the current combustion stroke cylinder, the fuel injection target cylinder, and the ignition target cylinder is provided in opposition.

Next, the configuration of an electronic control system for controlling the engine 1 will be described. Calculation of control amounts for actuators such as injector 11, igniter 19, ISC valve 10, and output of control signals, ie, fuel injection control,
Engine control such as ignition timing control and idle speed control is performed by an electronic control unit (ECU) 40 shown in FIG.

The ECU 40 includes a CPU 41, a ROM 42,
A RAM 43, a backup RAM 44, a counter / timer group 45, and an I / O interface 46 are mainly configured by a microcomputer connected to each other via a bus line, and a constant voltage circuit 47 for supplying a stabilized power to each unit. A peripheral circuit such as a drive circuit 48 and an A / D converter 49 connected to the O interface 46 is built in.

The counter / timer group 45 is used to generate various counters such as a free-run counter, a counter for counting the input of a cylinder discrimination sensor signal (cylinder discrimination pulse), a fuel injection timer, an ignition timer, and a periodic interrupt. The timer for periodic interruption, the timer for measuring the input interval of the crank angle sensor signal, and various timers such as a watchdog timer for monitoring system abnormalities are collectively referred to for convenience.
In addition, various software counters and timers are used.

The constant voltage circuit 47 is connected to the battery 51 via a first relay contact of a power supply relay 50 having two relay contacts, and is also directly connected to the battery 51. When the switch is turned on and the contact of the power supply relay 50 is closed, power is supplied to each unit in the ECU 40, while the ignition switch 52 is turned on.
Regardless of ON or OFF, always backup RAM4
4 is supplied with power for backup. Further, the fuel pump 14 is connected to the battery 51 via a relay contact of the fuel pump relay 53. The power relay 50
A power line for supplying power from the battery 51 to each actuator is connected to the second relay contact.

The input port of the I / O interface 46 includes an ignition switch 52, a knock sensor 2
6, a crank angle sensor 32, a cylinder discriminating sensor 35, a vehicle speed sensor 36 for detecting a vehicle speed, and the like are connected. Further, via an A / D converter 49, the intake air amount sensor 24, the throttle opening The temperature sensor 25, the cooling water temperature sensor 28, the O2 sensor 29, and the like are connected, and the battery voltage VB is input and monitored.

On the other hand, the output port of the I / O interface 46 has a relay coil of the fuel pump relay 53,
The SC valve 10, the injector 11, etc.
And the igniter 19 is connected.

In accordance with a control program stored in a ROM 42, the CPU 41 processes detection signals from sensors and switches, which are input via an I / O interface 46, a battery voltage, and the like. Based on the data, various learning value data stored in the backup RAM 44, fixed data stored in the ROM 42, etc., the fuel injection amount for each cylinder, the ignition timing for each cylinder, the duty ratio of the drive signal for the ISC valve 10, etc. And engine control such as cylinder-specific fuel injection control, cylinder-specific ignition timing control, idle speed control, and the like.

In such engine control, the ECU
In 40, when the engine operation state corresponds to at least one of a high load state such as acceleration or uphill running and a high rotation state such as during deceleration running, the exhaust gas temperature is corrected to increase the fuel and reduce the exhaust gas temperature. The reduction correction is executed to protect the catalyst and the like by preventing overheating of the exhaust system.

In this exhaust temperature reduction correction, overheating of the exhaust system is reliably prevented by taking into account the delay in temperature change due to the engine operating state and the heat capacity of the exhaust system. After returning to the normal operation state from the operation state corresponding to at least one of the above, before the set time elapses, when the operation state again corresponds to at least one of the high load state and the high rotation state In
Immediately increase fuel by exhaust temperature reduction correction to prevent overheating by coping with delay in exhaust system temperature drop,
Further, when the operation state corresponding to at least one of the high load state and the high rotation state after the set time elapses, the fuel increase by the exhaust temperature reduction correction is performed in a delay time set in advance according to the operation state. By executing the above, the temperature is surely lowered before the exhaust system is overheated while avoiding unnecessary fuel increase.

That is, the ECU 40 has the functions of the engine operating state determination means, the delay time setting means, and the fuel injection control means according to the present invention. Specifically, the functions of each means are realized by the routine shown in FIG. I do.

Hereinafter, processing related to the fuel injection control of the present invention, which is executed by the ECU 40, will be described with reference to the flowchart of FIG.

FIG. 1 shows a fuel injection amount setting routine executed at predetermined intervals after the system is initialized. First, in step S101, the engine is in a high load state due to acceleration, uphill running, or the like. Check whether or not. Whether the engine is in a high load state is determined, for example, by a basic fuel injection pulse width Tp (= K × Q / Ne; K) calculated from the intake air amount Q and the engine speed Ne as the engine load.
Is determined by determining whether the basic fuel injection pulse width Tp is equal to or greater than a set value.

As a result, when the engine is in a high load state, the process proceeds from step S101 to step S108 and thereafter. When the engine is not in a high load state, in step S102, the current engine speed Ne is read and the engine speed is read. It is checked whether or not Ne is in a high rotation state equal to or higher than the set rotation number. Then, when the engine is in the high rotation state, that is, when at least one condition of the high load state and the high rotation state is satisfied, the process similarly proceeds from step S102 to step S108 and thereafter to prevent heating of the exhaust system. For the exhaust gas temperature reduction correction is performed, and when the engine is not in the high load state and in the normal operation state that is not in the high rotation state, the process proceeds from step S102 to step S103.

First, step S10 in a normal operation state
Explaining about 3 and later, in step S103, it is determined whether or not the count value TMPR for measuring the elapsed time after the exhaust gas temperature reduction correction is canceled with the return to the normal operation state is equal to or longer than the set time TDILLY. Find out.

Then, TMPR <TDILLY, and
The initial state where neither the high load state nor the high rotation state has been reached, or the exhaust gas temperature reduction correction has already been performed, and this time, the normal state does not apply to both the high load state and the high rotation state. If it has just returned, step S10
The process proceeds from step 3 to step S104 to count up the count value TMPR (TMPR ← TMPR + 1), and then proceeds to step S106.

In step S103, TMPR ≧ TD
If the set time has passed after the exhaust temperature reduction correction is canceled, the flag FR is set in step S105.
ICH is set (FRICH ← 1), and step S10 is performed.
Proceed to 6. The flag FRICH indicates whether or not to provide a delay time when executing the exhaust temperature reduction correction. When at least one of the high load state and the high rotation state is satisfied, the exhaust temperature reduction correction is performed when FRICH = 1. Is executed with a delay time, and the exhaust temperature reduction correction is immediately executed when FRICH = 0.

In step S106, the count value TMRICH for measuring the elapsed time after at least one of the high load state and the high rotation state is satisfied is cleared (TMRICH ← 0). The exhaust gas temperature reduction correction coefficient KRICH for increasing the amount of fuel to prevent heating of the exhaust system is set to 0 (KRICH ← 0), which is substantially equivalent to no fuel increase amount correction.

Then, from step S107 to step S
115, the basic fuel injection pulse width Tp is added to the basic injection correction coefficient KMR, the output air-fuel ratio correction coefficient KFULL, the exhaust temperature reduction correction coefficient KRICH, and various correction coefficients KC obtained by adding other correction coefficients, and O2 sensor 29
-Fuel ratio feedback correction coefficient LAMB based on the output of
DA to set the effective injection pulse width Te (Te
← Tp × KMR × (KFULL + KC + KRICH) ×
LAMBDA).

The basic injection correction coefficient KMR is a correction coefficient for making the air-fuel ratio during normal partial operation stoichiometric, and as shown in FIG.
The correction map KMRMAP is set based on the basic fuel injection pulse width Tp representing the engine load. The output air-fuel ratio correction coefficient KFULL is used to increase the amount of fuel during high-power operation to secure the engine output. As shown in FIG.
Based on e and the basic fuel injection pulse width Tp representing the engine load, it is set with reference to a correction map KFULLMAP.

Thereafter, the process proceeds to step S116, in which the invalid pulse width Ts for compensating for the invalid injection time of the injector 11 that changes according to the battery voltage VB is added to the effective injection pulse width Te set in step S115, and the final value is determined. The typical fuel injection pulse width Ti (Ti ← Te + T
s) Exit the routine. As a result, a drive signal corresponding to the fuel injection pulse width Ti is output to the injector 11 of the fuel injection target cylinder at a predetermined timing.

In a normal operating state that is neither a high load state nor a high rotation state, the output air-fuel ratio correction coefficient KFULL and the exhaust gas temperature reduction correction coefficient KRICH at the effective injection pulse width Te are both 0, and the output air-fuel ratio For this reason, there is no fuel increase for reducing the exhaust gas temperature, and the air-fuel ratio is controlled to stoichiometric.

Next, the engine operation state becomes at least one of a high load state and a high rotation state,
A case where the process proceeds from step 101 or step S102 to step S108 will be described. As described above, in the operating state corresponding to at least one of the high load state and the high rotation state, the fuel increase correction for reducing the exhaust gas temperature is executed, but after the exhaust temperature reduction correction is canceled, the set time elapses. The execution timing of the exhaust gas temperature reduction correction differs depending on whether the exhaust gas temperature correction has been performed or not.

That is, even if the operation state returns to the normal operation state corresponding to at least one of the high load state and the high rotation state, and the fuel increase correction for reducing the exhaust gas temperature is canceled, the temperature of the exhaust system remains unchanged. It does not drop immediately. Therefore, after the cancellation of the exhaust reduction correction, until the set time elapses,
Again, when the operation state corresponds to at least one of the high load state and the high rotation state, the fuel increase is immediately performed by the exhaust gas temperature reduction correction, and after the set time has elapsed,
When the operation state corresponds to at least one of the high load state and the high rotation state, the fuel amount is increased by the exhaust temperature reduction correction in the delay time based on the engine operation state.

Therefore, in step S108, the flag F
See RICH. And FRICH = 1,
If the set time TDILLY has already elapsed after the cancellation of the exhaust gas temperature reduction correction, the process proceeds to step S109, and after at least one of the high load state and the high rotation state is satisfied, the fuel by the exhaust gas temperature reduction correction is used. Exhaust gas temperature reduction correction delay time MDILL that determines the time until the increase is performed
Set Y.

Exhaust gas temperature reduction correction delay time MDILLY
Is a delay time in which unnecessary fuel increase is not performed in consideration of an engine operating state and a delay in temperature rise due to heat capacity of the exhaust system, and overheating of the exhaust system can be reliably prevented. It is determined in advance by simulation or experiment based on Ne and the basic fuel injection pulse width Tp representing the engine load.

In the present embodiment, as shown in FIG. 2D, a correction map MDILLYM based on the engine speed Ne and the basic fuel injection pulse width Tp representing the engine load.
The optimal delay time is stored in the AP, and the higher the engine speed Ne and the greater the engine load, the faster the temperature rise in the exhaust system.
The delay time is short.

The above exhaust temperature reduction correction delay time MDI
After setting LLY, the process proceeds to step S110, where a count value TMRIC for measuring an elapsed time after at least one condition of a high load state and a high rotation state is satisfied.
It is checked whether or not H is equal to or longer than the exhaust temperature reduction correction delay time MDILLY. As a result, TMRICH <
In the case of MDILLY, the count value TMRICH is counted up in step S111 (TMRICH ← TM
RICH + 1), and proceeds to step S107 to set the exhaust gas temperature reduction correction coefficient KRICH to 0, which corresponds to substantially no fuel increase correction.

Then, the effective pulse width Te is set in step S115, and the final fuel injection pulse width Ti is set in step S116, and the routine exits. Therefore, the fuel increase by the exhaust gas temperature reduction correction is not performed until the elapsed time after at least one of the high load state and the high rotation state is satisfied reaches the exhaust gas temperature reduction correction delay time MDILLY.

After that, the elapsed time after at least one of the high load state and the high rotation state is satisfied reaches the exhaust temperature reduction correction delay time MDILLY, and step S11 is performed.
If TMRICH ≧ MDILLY at 0, step S
The process proceeds from step 110 to step S112 and the flag FRICH
Is cleared (FRICH ← 0) and the count value TMPR is cleared (TMPR ← 0) in step S113, and then the exhaust gas temperature reduction correction coefficient KRICH is set in step S114.

The exhaust temperature reduction correction coefficient KRICH determines the amount of fuel increase that can reduce the exhaust temperature and prevent overheating of the exhaust system in consideration of the engine operating state and the heat capacity of the exhaust system. As shown in FIG. 2 (c), it is set with reference to the correction map KRICHMAP based on the engine speed Ne and the basic fuel injection pulse width Tp representing the engine load.

In step S115, the basic fuel injection pulse width Tp is changed to the basic injection correction coefficient KMR, the output air-fuel ratio correction coefficient KFULL, and the exhaust temperature reduction correction coefficient KRICH.
And an air-fuel ratio feedback correction coefficient LAMBDA based on the output of the O2 sensor 29 to set the effective injection pulse width Te by multiplying the sum of the correction coefficient KC and the various correction coefficients KC obtained by adding the other correction coefficients. The final fuel injection pulse width Ti is set by adding the invalid pulse width Ts for compensating the invalid injection time of the injector 11 that changes according to the battery voltage VB to the injection pulse width Te, and the routine exits.

That is, in a high load state or a high rotation state, the fuel increase by the exhaust temperature reduction correction coefficient KRICH is performed until the delay time based on the engine speed Ne and the basic fuel injection pulse width Tp representing the engine load elapses. By executing the fuel increase by the output air-fuel ratio correction coefficient KFULL without executing the above, it is possible to obtain an optimum output air-fuel ratio while suppressing wasteful consumption of fuel, and obtain good responsiveness and output performance. After a lapse of time, the output air-fuel ratio correction coefficient K
In addition to fuel increase by FULL, exhaust temperature reduction correction coefficient K
By executing the fuel increase by the RICH, it is possible to suppress a rise in the exhaust gas temperature at an air-fuel ratio richer than the output air-fuel ratio and to prevent overheating of the exhaust system.

On the other hand, in step S108, FRICH = 0
In other words, in the case of, that is, when the fuel increase by the exhaust gas temperature reduction correction has already been executed last time, or when the exhaust gas temperature reduction correction has been canceled with the return to the normal operation state, the set time has still elapsed. If at least one of the high load state and the high rotation state is again performed before the start, the process jumps to step S112 to execute the fuel increase by the exhaust gas temperature reduction correction without passing through the delay time.

Then, as described above, step S11
After clearing the flag FRICH and the count value TMPR in steps S2 and S113, respectively, an exhaust gas temperature reduction correction coefficient KRICH is set in step S114.
5, In S116, the effective injection pulse width Te and the final fuel injection pulse width Ti are set, and the routine exits.

In this case, even if the operation state becomes at least one of the high load state and the high rotation state again within a short time after the return to the normal operation state, The fuel increase by the exhaust gas temperature reduction correction is executed immediately, and the overheating of the exhaust system is prevented by coping with the delay of the temperature decrease of the exhaust system.

[0056]

As described above, according to the first aspect of the present invention, it is determined whether the engine operating state corresponds to at least one of the high load state and the high rotation state, and the high load state is determined. When at least one of the state and the high-speed state is satisfied, when the delay time set based on the engine operating state elapses, the fuel injection is performed by performing exhaust temperature reduction correction to prevent heating of the exhaust system. Since the amount is increased, it is possible to surely lower the temperature before the exhaust system is overheated while avoiding an unnecessary increase in fuel, thereby preventing damage to the exhaust system components and improving reliability.

In this case, according to the second aspect of the invention, the engine operation state becomes at least one of a high load state and a high rotation state before the elapsed time after the cancellation of the exhaust gas temperature reduction correction reaches the set time. In this case, since the fuel injection amount is increased by the exhaust gas temperature reduction correction without waiting for the delay time to elapse, it is possible to prevent overheating by coping with a delay in the temperature decrease of the exhaust system. In the invention according to claim 3,
Since the delay time before executing the exhaust temperature reduction correction is set based on the engine speed and the engine load,
An optimal delay time that accurately reflects the engine operating state can be obtained, and excellent effects such as improvement in controllability can be obtained.

[Brief description of the drawings]

FIG. 1 is a flowchart of a fuel injection amount setting routine.

FIG. 2 is an explanatory diagram of each correction map.

FIG. 3 is an overall schematic diagram of an engine.

FIG. 4 is a circuit configuration diagram of an electronic control system.

[Explanation of symbols]

1 ... Engine 40 ... ECU (engine operation state discriminating means, delay time setting means, fuel injection control means) Ne ... engine speed Tp ... basic fuel injection pulse width (engine load) MDILLY ... exhaust temperature reduction correction delay time KRICH ... exhaust Temperature reduction correction coefficient Ti: fuel injection pulse width

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G301 HA01 HA08 JA02 JA32 KA09 KA11 KA25 LB02 MA01 MA12 NA06 NA08 NB02 NB06 NB11 NC02 ND01 NE01 NE13 NE14 NE22 PA04Z PA11Z PA17Z PB03Z PC08Z PD02A PD02Z PD11Z PE01Z PE03Z01

Claims (3)

[Claims] An engine operating state determining means for determining whether an engine operating state corresponds to at least one of a high load state and a high rotation state; and determining whether the engine operation state is a high load state and a high rotation state. Delay time setting means for setting a delay time until executing exhaust temperature reduction correction for preventing exhaust system heating based on the engine operating state, when it is determined that the state corresponds to at least one of the states, Fuel injection control means for increasing the fuel injection amount by the exhaust temperature reduction correction when the elapsed time after the state has at least one of the high load state and the high rotation state has reached the delay time; A fuel injection control device for an engine, comprising: 2. The fuel injection control device according to claim 1, wherein the engine operation state is changed to at least one of a high load state and a high rotation state before an elapsed time after the cancellation of the exhaust gas temperature reduction correction reaches a set time. 2. The fuel injection device for an engine according to claim 1, wherein when the delay time has elapsed, the fuel injection amount is increased by the exhaust gas temperature reduction correction without waiting for the delay time to elapse. 3. The engine fuel injection control device according to claim 1, wherein the delay time setting means sets the delay time based on an engine speed and an engine load.