JP2002047971A - Engine controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine controller capable of controlling an increase of a supply fuel amount closely when an engine has a high load, improving exhaust gas purifying performance and fuel economical property, and protecting catalyst accurately. SOLUTION: The increase in the supply fuel amount is compensated and controlled with an increase value corresponding to a catalyst temperature of a catalyst device or a temperature representing it when the engine is operated with a high load.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control device, and more particularly to an engine control device for controlling a fuel supply amount of a vehicle engine having an exhaust gas purifying catalyst device in an exhaust system.

[0002]

2. Description of the Related Art When an engine (internal combustion engine) is operated under a high load condition, the exhaust gas temperature rises with an increase in the calorific value of the engine, and an exhaust gas purifying catalyst provided in the middle of an exhaust passage. The catalyst temperature of the device (catalytic converter) also becomes high. Higher temperature of the catalyst leads to thermal deterioration of the catalyst metal supported on the catalyst, and shortens the life of the catalyst device.

For this reason, generally, a temperature sensor and / or temperature switches for monitoring the temperature state of the catalyst are set near the catalyst device main body or the catalyst device so as to detect that the temperature of the catalyst has become high. When a high temperature condition is detected, a warning is displayed on an instrument panel or the like in the driver's seat to notify the driver of the progress of catalyst thermal deterioration.

In high load operation, generally, an air-fuel ratio giving priority to output is set to increase the fuel supply amount more than in partial load operation. The output-priority air-fuel ratio deviates from the stoichiometric air-fuel ratio region where the conversion efficiency of the generally employed three-way catalyst is maximized, which causes a reduction in exhaust performance.However, an increase in fuel causes an increase in fuel in the engine combustion chamber. As the heat of vaporization increases and the temperature in the combustion chamber decreases, the temperature of the exhaust gas decreases and the effect of suppressing an increase in the catalyst temperature can be obtained.

A technique for suppressing a rise in exhaust gas temperature by correcting an increase in the amount of fuel and avoiding overheating of the catalyst is as follows.
This is disclosed in JP-A-7-173197. From this, it is determined from the throttle opening, the intake air amount, etc., that the operating state of the engine is in a high load state, and in the high load state, the output priority air-fuel ratio smaller than the stoichiometric air-fuel ratio, or Further, there has been proposed an engine control device that performs control to increase the amount of supplied fuel and suppresses an increase in catalyst temperature by combustion at a rich air-fuel ratio.

[0006]

However, in the conventional engine control device, when a high load state is determined based on the throttle opening, the intake air amount, and the like, the fuel is uniformly supplied immediately regardless of the catalyst temperature at this time. The exhaust gas performance is reduced, and the fuel consumption is reduced. In particular, in recent years, from the viewpoints of low pollution and resource saving, it is desired to perform more preferable and finer engine control in all aspects of exhaust gas purification performance, fuel economy, and catalyst protection.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to more precisely control the amount of fuel supplied when the engine is under a high load, thereby improving exhaust gas purification performance and fuel economy. It is an object of the present invention to provide an engine control device capable of improving the performance and appropriately protecting the catalyst.

[0008]

In order to achieve the above object, an engine control apparatus according to the present invention comprises an engine control apparatus having an exhaust gas purifying catalyst device in an engine exhaust system. Operating condition detecting means for detecting the temperature of the catalyst, a temperature detecting means for detecting a catalyst temperature of the catalyst device or a temperature representative thereof, and detecting and determining a high load operating condition based on the operating condition detected by the operating condition detecting device. In a high load operation state, there is provided control means for performing increase correction control of supplied fuel with an increase value corresponding to the temperature detected by the temperature detection means.

Thus, the increase correction control during the high load operation state can be performed with an appropriate value without any excess or deficiency in consideration of the catalyst temperature or the temperature representative thereof. As a specific example of the increase correction control in the high load operation state, the control unit outputs the output when the temperature detected by the temperature detection unit is equal to or higher than the specified value for catalyst protection in the high load operation state. The fuel supply increase correction control is performed with the specified increase value for performing the priority and the catalyst protection.If the temperature detected by the temperature detecting means is not higher than the catalyst protection specified value during the high load operation state, the specified value is set. The increase correction control of the supplied fuel can be performed with an increase value (including 0) smaller than the increase value.

An engine control device according to the present invention is an engine control device having an exhaust gas purifying catalyst device in an engine exhaust system, wherein the operating condition detecting means for detecting the operating condition of the engine; Temperature detecting means for detecting a catalyst temperature or a temperature representative of the catalyst, and detecting and determining a first high-load operating state and a second high-load operating state based on the operating state detected by the operating state detecting means. In the first high-load operation state, the supply-fuel increase correction control is performed with a specified increase value for performing output priority and catalyst protection. In the second high-load operation state, the correction is performed in accordance with the temperature detected by the temperature detection means. Control means for performing the increase correction control of the supplied fuel with the increased increase value.

Thus, in the first high load operation state, the increase correction control of the supplied fuel is performed regardless of the catalyst temperature with the specified increase value for performing the output priority and the catalyst protection.
In the high load operation state, the increase correction control can be performed with an appropriate value without any excess or deficiency in consideration of the catalyst temperature or the representative temperature.

As a specific example of the increase correction control in the second high-load operation state, the control means determines that the temperature detected by the temperature detection means in the second high-load operation state is a catalyst protection regulation. If the temperature is equal to or more than the specified increase value, the increase correction control of the supplied fuel is performed using the specified increase value. The value (including 0) may be used to perform the supply fuel increase correction control.

Further, the control means of the engine control apparatus according to the present invention may be configured to perform the following control. (1) A preset reference temperature is compared with a temperature catalyst temperature detected by the temperature detecting means, and the increase value is determined based on the comparison result. (2) A preset reference temperature is compared with a temperature detected by the temperature detecting means, and the increase value is feedback-controlled so that the comparison result converges within a predetermined temperature range. (3) The increase value is feedback-controlled so that the temperature detected by the temperature detecting means converges within a predetermined temperature range set in advance.

The determination of the load state of the engine in the engine control apparatus according to the present invention is based on the detected value of the throttle valve opening of the engine or based on the state in which the throttle valve opening reaches a predetermined opening. At least one of at least one of: based on a switch to be detected, based on a calculation parameter calculated based on an intake air amount of the engine, or based on a calculation parameter calculated based on a detected value of the engine speed. Can be performed using the above information.

In the engine control apparatus according to the present invention, the detection of the catalyst temperature of the catalyst device or a temperature representative thereof is based on a value detected by a temperature sensor or a switch for detecting a state where a predetermined temperature has been reached. Based on a calculation parameter calculated based on an intake air amount of the engine, or based on a calculation parameter including a history of an operation state calculated based on a detected value of an engine rotation speed, or mounted with an engine. Or at least one of information based on calculation parameters including a history of driving states calculated based on the detected vehicle speed of the vehicle.

Further, the control means of the engine control device according to the present invention determines an engine high output request by a driver, and based on the determination result, determines an increase value of the supply fuel increase control in a direction in which the engine output increases. Can be configured to perform the increase correction.

The driver's request for high engine output is determined by detecting the amount of change in the throttle valve opening of the engine during a predetermined period and / or the period required for a change between predetermined ranges.
Alternatively, the amount of change in the accelerator opening in a predetermined period and / or the period required for a change between predetermined ranges is detected, the amount of change in the engine intake air amount in a predetermined period and / or the period required for a change between predetermined ranges is detected, and the engine suction pipe pressure is detected. Of the change amount in the predetermined period and / or the detection of the period required for the change between the predetermined ranges.

Further, the engine control device according to the present invention performs a failure / abnormality determination of the load state detection / determination section by the operating state detecting means and the control means. Is stopped, and if the temperature detected by the temperature detecting means is equal to or higher than the specified value for catalyst protection, the increase correction of the supplied fuel is performed using the increased value for protecting the catalyst.

Further, the engine control device according to the present invention performs a failure / abnormality determination of the temperature determining unit by the temperature detecting means and the control means, and stops the increase correction control of the supplied fuel when the failure / abnormality determination is made. It is.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows an entire system of a fuel injection type internal combustion engine to which an engine control device according to the present invention is applied. ing. The engine body 1 has a piston 3 in a combustion chamber 2 of each cylinder, and the piston 3 is connected to a crankshaft 5 by a connecting rod 4.
It is connected to.

The intake port 6 of the engine body 1 is provided with an intake valve 7
The intake port 6 is connected to an air cleaner 8, an air flow sensor 9 for detecting the amount of intake air, a throttle valve 10 for controlling the amount of intake air, and an intake pipe 11, through which the combustion of each cylinder is performed. Air is sucked into the chamber 2.

The engine body 1 is provided with a fuel injection valve 12 for injecting fuel into the intake port 6 and a spark plug 13 for generating a spark in the combustion chamber 2. An exhaust port 14 of the engine body 1 is opened and closed by an exhaust valve 15, and an exhaust pipe 16 and a three-way catalytic converter 17 are connected to the exhaust port 14, through which exhaust gas is exhausted.

Each part of the engine includes a throttle opening sensor 21, a cooling water temperature sensor 22, a knock sensor 23,
A crank angle sensor 24, an air-fuel ratio sensor 25, and an exhaust gas temperature sensor 26 are provided. The detection values of these sensors are
It is input to an electronic control unit (hereinafter, referred to as ECU) 30.

As shown in FIG. 2, the ECU 30 includes a CPU 31, a ROM 32 in which a system program for engine control, constants necessary for engine control, and the like are written.
And a RAM 33 used as a work memory or the like for storing a value of an input signal, a calculation result, and the like, and inputting an output signal of each of the above-described sensors via an input circuit 35, and sending a signal to a driving circuit or an output circuit described later. I / O port 34 that outputs
And

The CPU 31 reads the input signal from the input / output port 34 based on a program or a constant stored in the ROM 32, and reads an intake air amount, an engine rotation speed, a crank angle, a coolant temperature, a throttle opening, a knock generation signal. And the like, or perform their arithmetic processing.

The CPU 31 further outputs a command signal relating to the ignition timing and the injector drive pulse width to the ignition output circuit 36 and the fuel injection valve drive circuit 37 via the input / output port 34 as a result of the arithmetic processing. Execute fuel injection control. Further, the CPU 31 determines whether or not the exhaust gas temperature detected by the exhaust gas temperature sensor 26 is at an abnormally high temperature.
The warning light drive circuit 38 controls to turn on the exhaust temperature warning light 27.

The fuel is pressure-fed from a fuel tank (not shown) by a fuel pump, is maintained at a predetermined pressure by a fuel pressure regulator, is supplied to the fuel injection valve 12, and is supplied with a predetermined amount at a predetermined timing by a drive pulse output from the ECU 30. It is injected into the intake port 6. An air-fuel mixture of fuel and intake air enters the fuel chamber 2 through the intake port 6 and the ignition plug 13
It is ignited and burns. The exhaust gas after combustion is exhausted from an exhaust port 14 to an exhaust pipe 16 and flows into a three-way catalytic converter 17.

The air-fuel ratio sensor 25 outputs a signal corresponding to the oxygen concentration in the exhaust gas upstream of the three-way catalytic converter 17, and the ECU 30 outputs a signal based on the oxygen concentration in the exhaust gas detected by the air-fuel ratio sensor 25. Then, the air-fuel ratio (fuel injection amount) of the air-fuel mixture is feedback-controlled so as to reach the target air-fuel ratio.

The exhaust temperature sensor 26 outputs a signal corresponding to the temperature of the exhaust gas immediately below the three-way catalytic converter 17, and the ECU 30 can detect the temperature state of the three-way catalytic converter 17 from the output. Further, the exhaust gas temperature sensor 26 is configured to be directly inserted into the three-way catalytic converter 17,
It is also possible to measure the temperature according to the temperature of the catalyst body of the three-way catalytic converter 17, such as measuring the temperature of the exhaust gas in the catalyst, calculating the temperature of the catalyst carrier, and measuring the wall temperature of the catalyst holding tube (converter case). it can.

FIG. 3 illustrates the relationship between the engine air-fuel ratio, engine torque, and fuel efficiency. The mass ratio between the fuel supplied to the engine and the intake air amount is the air-fuel ratio, and there is a relationship between the engine torque and the fuel consumption rate as shown in the figure according to the air-fuel ratio. Therefore, when the air-fuel ratio gives priority to the engine torque, the fuel consumption rate deteriorates.

FIG. 4 shows the relationship between the exhaust gas conversion efficiency of the three-way catalyst and the air-fuel ratio. It is understood that when the air-fuel ratio deviates from the range near the stoichiometric air-fuel ratio, the conversion efficiency of the harmful exhaust gas component deteriorates. From the above, it is important to perform fine fuel supply control in a high engine load state in relation to the driving performance, exhaust performance, fuel consumption performance, and protection of the catalyst from high temperatures.

The engine control device of the present invention controls the increase of the fuel supply amount under a high load condition. The increase control will be described with reference to FIG. ECU 30
Monitors the engine load based on the throttle opening θ detected by the throttle opening sensor 21, and determines that the engine is in a high load state when the throttle opening θ is equal to or more than a predetermined value θs.

The ECU 30 calculates the throttle opening change speed by differential operation of the throttle opening θ, and if the throttle opening change speed is a large acceleration as shown by acceleration A in FIG. At the time t0 when the throttle opening .theta. Becomes equal to or more than the predetermined value .theta.s, the air-fuel ratio is immediately shifted to the output-priority air-fuel ratio, and the control for giving priority to the output performance is performed.

On the other hand, as shown by the acceleration B in FIG. 5, at the time of gentle acceleration in which the throttle opening change speed is not fast, at the time t1, the throttle is opened at time t1 in order to achieve a balance between the output performance, the exhaust performance, and the fuel efficiency. Even if the opening degree θ becomes equal to or greater than the predetermined value θs, the load is maintained under a high load condition until the catalyst temperature (exhaust gas temperature) T reaches a preset catalyst protection set value (catalyst temperature limiter) Ts (until time point Tt2). A fuel increase value F corresponding to the air-fuel ratio for protecting the catalyst at the same time as the output priority,
Control is performed to limit the fuel increase value Fm to less than p. When the catalyst temperature T exceeds the catalyst protection set value Ts, the fuel increase value is increased so as to be equivalent to the air-fuel ratio for protecting the catalyst. At this time, the increase amount ΔF can be variably set according to the difference temperature between the catalyst protection set value Ts and the actual catalyst temperature, and it is possible to further improve exhaust performance and fuel efficiency.

Further, a target catalyst temperature zone set lower than the catalyst protection set value Ts may be provided, and feedback control (feedback control) may be performed so as to control the catalyst temperature to the median value. With this feedback control, it is possible to suppress a sudden change in the fuel supply amount and prevent a sudden change in the engine torque. Next, a description will be given, with reference to the flowchart of FIG. 6, of the fuel supply amount increase control by the engine control device according to the present invention at the time of a high load state.

First, it is determined whether or not a failure (abnormality) has occurred in the high load state determination (step S601).
If a failure has occurred (Yes at Step S601), it is determined whether or not the catalyst temperature T is higher than or equal to a high temperature state (catalyst protection set value Ts) requiring catalyst protection (Step S607). If it is determined that T is in a high temperature state that requires protection of the catalyst, the fuel increase correction is performed (step S608), in which case the correction amount is set to an increase control amount under high load. It is also possible to use EC
U30 has a self-diagnosis function for detecting the operation state detecting means (various sensors) and detecting the failure / abnormality of the load state.

If no failure has occurred in the high load state determination (No at step S601), it is determined whether or not a high load state exists (step S602). When it is not in the high load state (No at Step S602), the correction amount of the high load control amount at the time of calculating the fuel supply amount is set to 0, and the increase under the high load state is not performed (Step S606).

If it is determined that the vehicle is in a high load state (Yes at step S602), the throttle opening θ
Is detected, and it is determined whether or not the driver requests a high output (step S603). If it is determined that the high output is a request (Yes at Step S603), the correction amount of the first high load control amount is set to 1, and the power air-fuel ratio state is set (Step S604). If it is determined that the request is not the request for the maximum output (No at Step S603), the second control amount under high load is calculated and the control amount under high load is corrected (Step S605).

Next, the control amount correction under high load in step S605 will be described with reference to the flowchart of FIG. First, it is determined whether or not the catalyst temperature T is equal to or higher than the catalyst protection set value Ts (step S701).
Is not greater than or equal to the catalyst protection set value Ts (step S70).
1 negative), the correction amount of the control amount under high load is 1 ≧ correction amount ≧
By setting it to 0, for example, 0.3, the exhaust gas performance and fuel efficiency are improved.

The correction amount of the control amount at high load at this time is determined by a value based on the change amount of the throttle opening and the actual catalyst temperature (catalyst temperature T) or the difference between the catalyst protection set value Ts and the actual catalyst temperature. By doing so, it is possible to further improve the balance between the driving performance, the exhaust performance, and the fuel efficiency.

If the catalyst temperature T is not equal to or higher than the catalyst protection set value Ts (step S701: YES),
The control amount under high load is set to 1, the power air-fuel ratio state is set, and the exhaust gas temperature is reduced (step S70).
2). The present control can also be realized by using the catalyst temperature estimated value calculated in the control device as the catalyst temperature.

The control of increasing the fuel supply amount under the high load condition by the engine control device according to the present invention is performed in addition to the above-described control.
A second medium-high load that adjusts a balance between a high load region in which the engine load region is in a power air-fuel ratio state and a fuel increase in order to protect power and a catalyst, and a fuel reduction in order to improve exhaust performance and fuel efficiency. The fuel supply amount according to each state may be calculated by dividing the region into a region and a medium-low load region that emphasizes exhaust performance and fuel efficiency.

Regarding the fuel supply amount increase control in this case,
This will be described with reference to the flowchart of FIG. First, it is determined whether or not a failure (abnormality) has occurred in the load state determination (step S681). If a failure has occurred (Yes at Step S801), it is determined whether or not the catalyst temperature T is higher than or equal to a high temperature state that requires protection of the catalyst (the catalyst protection set value Ts) (Step S806). If it is determined that T is in a high temperature state that requires protection of the catalyst, a fuel increase correction is performed (step S806).

If no failure has occurred in the high load state determination (No at step S801), the load region is determined according to the engine load state (step S80).
2). In the case of the low and medium load region (state), the load control at the time of calculating the fuel supply amount is not performed.

If it is determined that the vehicle is in the first high-load region (state) in which the power air-fuel ratio is to be set, a high-load control amount is set and the power air-fuel ratio is set (step S80).
3). On the other hand, when it is determined to be in the second high load region (state), a second high load control amount is calculated, and the fuel control increase correction is performed. The procedure for performing the second fuel increase correction at the time of high load is the same as that shown in FIG.

The detection / judgment of the engine high load state is based on a detected value of the throttle valve opening, or based on a switch for detecting a state where the throttle valve opening reaches a predetermined opening, or At least one of at least one of a calculation parameter calculated in the engine control device based on the intake air amount of the engine, and a calculation parameter calculated in the engine control device based on the detected engine speed value Can be performed using the above information.

The detection / estimation of the catalyst temperature or the exhaust gas temperature in the vicinity of the catalyst is based on a value detected by a temperature sensor, based on a switch for detecting a state where a predetermined temperature has been reached, or on the engine. Either based on calculation parameters calculated in the engine control device based on the intake air amount, or based on calculation parameters including a history of operating conditions calculated in the engine control device based on the detected engine rotation speed, or The determination can be performed using at least one piece of information based on calculation parameters including a history of driving states calculated in the engine control device based on the vehicle speed detection value of the mounted vehicle.

The determination of the driver's request for a high engine output is made by detecting the amount of change in the throttle valve opening during a predetermined period and / or the period required to change between predetermined ranges, or the amount of change in the accelerator opening during a predetermined period. Alternatively, detection of a period required for a change between predetermined ranges, detection of a change amount of the engine intake air amount in a predetermined period / or detection of a period required for a change between the predetermined ranges, change amount of an engine intake pipe pressure for a predetermined period / or between predetermined ranges. The detection can be performed using at least one piece of information of any one of the detections of the period required for the change of.

The engine control apparatus according to the present invention performs a failure / abnormality determination of the temperature by the exhaust gas temperature sensor 26 or the ECU 30. When the failure / abnormality determination is made, the amount of supplied fuel in the high load state as described above is increased. The correction control can be stopped.

[0050]

As described above, according to the engine control apparatus of the present invention, the increase correction control during the high load operation state has an appropriate value without any excess or deficiency in consideration of the catalyst temperature or the representative temperature. As a result, the supply fuel increase control at the time of high engine load is performed more finely, and the exhaust gas purification performance and fuel economy are improved, and accurate catalyst protection is effectively achieved.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing an overall system of a fuel injection type internal combustion engine to which an engine control device according to the present invention is applied.

FIG. 2 is a block diagram showing a control system of the engine control device according to the present invention.

FIG. 3 is a graph showing a relationship between an engine air-fuel ratio, an engine torque, and fuel efficiency.

FIG. 4 is a graph showing a relationship among a three-way catalyst, an exhaust gas conversion efficiency, and an air-fuel ratio.

FIG. 5 is a graph showing a specific example of high load increase control in the engine control device according to the present invention.

FIG. 6 is a flowchart showing one embodiment of fuel control in the engine control device according to the present invention.

FIG. 7 is a flowchart showing one embodiment of high load increase control in the engine control device according to the present invention.

FIG. 8 is a flowchart showing another embodiment of the fuel control in the engine control device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine main body 2 Combustion chamber 9 Air flow sensor 10 Throttle valve 12 Fuel injection valve 13 Spark plug 17 Three-way catalytic converter 25 Air-fuel ratio sensor 26 Exhaust temperature sensor 30 ECU

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) F02D 45/00 312 F02D 45/00 312K 312R 314 314R 345 345E (72) Inventor Mitsuru Nagase Hitachinaka Ibaraki, Ibaraki Location 2477 F-term in Hitachi Car Engineering Co., Ltd. (reference) 3G084 BA13 BA24 CA04 DA02 DA20 DA37 EB11 FA07 FA10 FA11 FA20 FA26 FA27 FA29 FA33 FA38 3G301 HA01 JA02 JA21 JA33 JB01 JB03 KA09 LA01 LB02 MA01 MA11 ND01 NE01 NE13 NE01 PA01 PA08Z PA11Z PA12Z PB03A PB03Z PC08Z PD02A PD02Z PD12A PD12B PD12Z PE01Z PE03Z PE08Z PF01Z

Claims (13)

[Claims] 1. An engine control device having an exhaust gas purifying catalyst device in an engine exhaust system, comprising: an operating condition detecting means for detecting an operating condition of the engine; and a catalyst temperature of the catalyst device or a temperature representative thereof. Temperature detecting means for detecting, and detecting and determining a high load operating state based on the operating state detected by the operating state detecting means, and in a high load operating state, an increase value according to the temperature detected by the temperature detecting means. An engine control device, comprising: a control unit that performs an increase correction control of supply fuel with the control unit. 2. The control device according to claim 1, wherein when the operation is in a high load operation state and the temperature detected by the temperature detection unit is equal to or higher than a predetermined value for catalyst protection, a predetermined increase value for performing output priority and catalyst protection. Performs the fuel supply increase correction control with
In the high load operation state, when the temperature detected by the temperature detecting means is not equal to or more than the specified value of the catalyst protection, the increase correction of the supply fuel is performed with the increased value (including 0) smaller than the specified increased value. 2. The method according to claim 1, wherein
An engine control device according to item 1. 3. An engine control device having an exhaust gas purifying catalyst device in an engine exhaust system, comprising: an operating condition detecting means for detecting an operating condition of the engine; and a catalyst temperature of the catalyst device or a temperature representative thereof. Detecting a first high-load operation state and a second high-load operation state based on an operation state detected by the temperature detection means to be detected, and a first high-load operation state; In some cases, the supply fuel increase correction control is performed using a prescribed increase value for performing output priority and catalyst protection. In the second high load operation state, the supply fuel increase is performed using an increase value corresponding to the temperature detected by the temperature detection means. An engine control device, comprising: control means for performing correction control. 4. When the temperature detected by the temperature detecting means is equal to or higher than a specified value for protecting the catalyst during the second high load operation state, the control means controls the fuel supply with the specified increased value. If the temperature detected by the temperature detecting means is not equal to or higher than the specified value for catalyst protection, the increased fuel supply correction control is performed with an increased value (including 0) smaller than the specified increased value. The engine control device according to claim 3, wherein: 5. The controller according to claim 1, wherein the controller compares a preset reference temperature with a temperature catalyst temperature detected by the temperature detector, and determines the increase value based on the comparison result. The engine control device according to any one of Items 1 to 4. 6. The control means compares a preset reference temperature with a temperature detected by the temperature detection means, and makes a comparison result converge within a predetermined temperature range.
The feedback control of the increase value is characterized in that:
The engine control device according to any one of Claims 4 to 5. 7. The apparatus according to claim 1, wherein the control means performs feedback control on the increase value so that the temperature detected by the temperature detection means converges within a predetermined temperature range set in advance. The engine control device according to any one of Claims 4 to 5. 8. The detection determination of the load state of the engine is based on a detected value of the throttle valve opening of the engine, or based on a switch for detecting a state where the throttle valve opening has reached a predetermined opening, or The operation is performed using at least one of information based on a calculation parameter calculated based on an intake air amount of an engine or a calculation parameter calculated based on a detected value of an engine rotation speed. The engine control device according to any one of claims 1 to 7, characterized in that: 9. The detection of the catalyst temperature of the catalyst device or a temperature representative thereof is based on a value detected by a temperature sensor, based on a switch for detecting a state where a predetermined temperature has been reached, or based on engine intake. Based on a calculation parameter calculated based on the air amount, based on a calculation parameter including a history of the operating state calculated based on the engine rotation speed detection value, or based on a vehicle speed detection value of a vehicle on which the engine is mounted. The engine control according to any one of claims 1 to 8, wherein the control is performed using at least one piece of information, based on a calculation parameter including a history of an operation state calculated based on the information. apparatus. 10. The control means judges a request for a high engine output by a driver and, based on the result of the judgment, corrects an increase value of the increase control of the supplied fuel in a direction to increase the engine output. Any one of claims 1 to 9
The engine control device according to the paragraph. 11. A driver's request for a high engine output is determined by detecting a change amount of a throttle valve opening of an engine in a predetermined period and / or a period required for a change between predetermined ranges, or a change of an accelerator opening in a predetermined period. amount/
Alternatively, the period required for the change between the predetermined ranges is detected, the change amount of the engine intake air amount in the predetermined period / or the period required for the change between the predetermined ranges is detected, the change amount of the engine intake pipe pressure in the predetermined period / or between the predetermined ranges. 11. The engine control device according to claim 10, wherein the detection is performed using at least one piece of detection information of any one of the periods required for the change of the engine speed. 12. A failure / abnormality determination of a load state detection / determination unit by the operation state detection means and the control means,
At the time of failure / abnormality determination, the supply fuel increase correction control is stopped, and if the temperature detected by the temperature detecting means is equal to or higher than the catalyst protection specified value, the supply fuel increase correction control is performed using the increase value for catalyst protection. The engine control device according to any one of claims 1 to 11, wherein the control is performed. 13. A malfunction / abnormality judgment of a temperature judging unit by said temperature detecting means and said control means, and when the malfunction / abnormality judgment is made, the increase correction control of the supplied fuel is stopped. The engine control device according to claim 1.