JP7363727B2 - Internal combustion engine control devices and internal combustion engine systems - Google Patents

Description

The present disclosure relates to an internal combustion engine control device and an internal combustion engine system.

BACKGROUND ART It has been known that estimating piston temperature is useful in order to understand the life span of pistons exposed to high pressure and high temperature environments.

For example, in Patent Document 1, the amount of heat generated in the internal combustion engine is estimated based on state information indicating the state of the internal combustion engine (engine speed, injection amount instructed to the fuel injection valve), and based on the estimated amount of heat generated, An internal combustion engine lubricating oil supply system that estimates piston temperature is disclosed.

Japanese Patent Application Publication No. 2011-256787

By the way, in the technique described in Patent Document 1, for example, when the piston temperature is estimated based on the instructed injection amount in a state where there is a discrepancy between the actual fuel injection amount and the instructed injection amount, the piston estimated temperature There is a problem that the accuracy of Furthermore, there is also the problem that it becomes difficult to accurately grasp the life span of the piston.

An object of the present disclosure is to provide an internal combustion engine control device and an internal combustion engine system that can improve the accuracy of estimated piston temperature.

In order to achieve the above object, an internal combustion engine control device in the present disclosure includes:
a learning unit that learns a difference between an actual injection amount of fuel injected by a fuel injection valve arranged corresponding to a cylinder of the internal combustion engine and an instruction injection amount for the fuel injection valve;
a storage unit that stores the difference as a learned value for each region divided by engine speed and fuel injection amount;
a correction unit that corrects the instructed injection amount based on the difference as a learning value stored in the storage unit ;
a temperature estimation unit that estimates a piston temperature of the internal combustion engine based on the corrected instructed injection amount and the engine rotation speed ;
Equipped with
The learning unit further includes, based on the detected value of the intake air amount detected by the intake air amount sensor, the stoichiometric air-fuel ratio, the actual value of the air-fuel ratio detected by the lambda sensor, and the instructed injection amount, learning the difference;
The learning unit further averages the actual value of the air-fuel ratio, averages the calculated value of the air-fuel ratio calculated based on the detected value of the intake air amount and the instructed injection amount, and calculates the averaged value of the air-fuel ratio. The difference is calculated using the actual value of the fuel ratio and the calculated value of the air-fuel ratio .

The internal combustion engine system in the present disclosure includes:
A control device for the internal combustion engine described above is provided.

According to the present disclosure, the accuracy of estimated piston temperature can be increased.

FIG. 1 is a functional block diagram showing part of an internal combustion engine system including an internal combustion engine control device according to the present embodiment. FIG. 2 is a flowchart showing an example of the operation of the internal combustion engine control device.

Embodiments of the present disclosure will be described below with reference to the drawings.
In this embodiment, a case will be described in which the present invention is applied to a diesel engine (internal combustion engine) installed in an automobile.

FIG. 1 is a functional block diagram showing a part of an internal combustion engine system 1 including an internal combustion engine control device 100 according to the present embodiment.

The internal combustion engine system 1 according to the present embodiment includes a diesel engine (not shown) (hereinafter simply referred to as the engine), a fuel injection valve (injector) arranged corresponding to the cylinder of the engine, an intake air amount sensor 2, and a lambda. It includes a sensor 3, an exhaust temperature sensor 4, a crank angle sensor 5, an oil temperature sensor 6, an accelerator opening sensor 7, and a control device 100.

The intake air amount sensor 2 detects the amount of intake air drawn into the cylinder from an air cleaner (not shown). The intake air amount sensor 2 is also called a mass flow sensor (MAF).

The lambda sensor 3 detects the actual value (actual λ) of the air-fuel ratio based on the amount of oxygen in the exhaust gas of the engine.

The exhaust temperature sensor 4 detects the temperature of the engine exhaust gas.

Crank angle sensor 5 detects the crank angle of the engine. The control unit 50 (described later) calculates the amount of change in the crank angular velocity from the detected value of the crank angle sensor 5.

The oil temperature sensor 6 detects, for example, the temperature of lubricating oil stored in an oil pan (not shown). Lubricating oil is used to lubricate various parts including the engine.

The accelerator opening sensor 7 detects an instruction injection amount (instruction value for the injector) according to the amount of depression of an accelerator pedal (not shown).

The internal combustion engine control device 100 according to the present embodiment includes a control unit 50 having an acquisition unit 10, a learning unit 20, a correction unit 30, and a temperature estimation unit 40.

The control unit 50 is, for example, an ECU (Electronic Control Unit) that includes a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. (not shown), and an input/output device. Each sensor 2 , 3 , 4 , 5 , 6 , 7 is connected to an input circuit of the control unit 50 .

The acquisition unit 10 acquires the detection results of the sensors 2, 3, 4, 5, 6, and 7.

The learning unit 20 calculates the intake air amount detected by the intake air amount sensor 2, the actual value (actual λ) of the air-fuel ratio detected by the lambda sensor 3, the theoretical air-fuel ratio (here, 14.6), and the command injection. The difference between the actual injection amount and the instructed injection amount is calculated based on the amount.
The difference (learning value) is calculated using the following equations (1) and (2).
Learning value = (Instructed injection amount x (Actual λ - Calculated λ) / Actual λ) * Coefficient... (1)
Calculation λ=Intake air amount/Instructed injection amount*14.6...(2)
Note that the coefficient can be determined by experiment or simulation.

The learning unit 20 averages each of the actual λ and the calculated λ. The learning unit 20 calculates the difference using the averaged actual λ and calculated λ. The calculated difference is stored in a memory (not shown) as a learning value for each region divided by engine speed and fuel injection amount.

The correction unit 30 corrects the instructed injection amount based on the difference (learning value) stored in the memory.

The temperature estimation unit 40 estimates the piston temperature of the internal combustion engine based on the corrected instructed injection amount and the engine rotation speed. The estimated piston temperature is referred to as "estimated piston temperature."

By the way, since the learned value is calculated based on the intake air amount detected by the intake air amount sensor 2, if the intake air sensor 2 is not normal, the accuracy of the estimated piston temperature may decrease.

Therefore, in the present embodiment, the control unit 50 controls the intake air temperature based on at least one of the engine exhaust temperature, the amount of change in the engine crank angular speed, and the temperature of lubricating oil (oil temperature) supplied to the engine. It is determined whether the quantity sensor 2 is normal. Note that, as described above, the exhaust gas temperature of the engine is detected by the exhaust gas temperature sensor 4. Further, the amount of change in the crank angular speed of the engine is calculated by the control unit 50 from the detected value of the crank angle sensor 5. Further, the temperature of lubricating oil (oil temperature) supplied to the engine is detected by an oil temperature sensor 6.

Specifically, the control unit 50 controls the engine when the exhaust gas temperature is less than a predetermined value, the amount of change in crank angular velocity is less than a predetermined value, and the amount of change Δ in oil temperature is less than a threshold value. In this case, it is determined that the intake air amount sensor 2 is normal. Further, the control unit 50 controls the learning unit 20 so that learning of the difference is performed when the intake air amount sensor 2 is normal.

With the above configuration, the learned value (difference) is calculated based on the intake air amount detected by the normal intake air amount sensor 2, the instructed injection amount is corrected based on the learned value, and the instructed injection amount is corrected based on the corrected instructed injection amount. Since the piston temperature is estimated based on the temperature of the piston, it is possible to suppress a decrease in the accuracy of the estimated piston temperature.

By the way, for example, when the engine is not operated under stable conditions, such as when the engine is warmed up, the effectiveness of learning by the learning section 20 decreases.

Therefore, in the present embodiment, when the engine is operated under stable conditions, control section 50 determines whether the engine is operated under stable conditions.

Specifically, if the engine has been warmed up, the engine is steady, and the lambda sensor 3 has high reliability, the control unit 50 determines that the engine is operating under stable conditions. do. Note that the lambda sensor 3 has high reliability when the actual value (actual λ) of the air-fuel ratio detected by the lambda sensor 3 is less than a predetermined threshold value (here, "3").

Further, the control unit 50 controls the learning unit 20 so that learning of the difference is performed when the engine is operated under stable conditions.

Next, an example of the operation of the internal combustion engine control device 100 according to the present embodiment will be described with reference to FIG. 2. FIG. 2 is a flowchart showing an example of the operation of the internal combustion engine control device 100. This flow starts when the engine starts, and is repeated at a predetermined period. In the following description, each function of the internal combustion engine control device 100 will be described as being executed by the CPU.

First, in step S100, the CPU determines whether the intake air amount sensor 2 is normal. If the intake air amount sensor 2 is normal (step S100: YES), the process transitions to step S110. If the intake air amount sensor 2 is not normal (step S100: NO), the flow shown in FIG. 2 is ended.

Next, in step S110, the CPU determines whether the engine is being operated under stable conditions. If the engine is being operated under stable conditions (step S110: YES), the process transitions to step S120. If the engine is not operated under stable conditions (step S110: NO), the flow shown in FIG. 2 ends.

First, in step S120, the CPU obtains the intake air amount detected by the intake air amount sensor 2.

Next, in step S130, the CPU obtains the actual value (actual λ) of the air-fuel ratio detected by the lambda sensor 3.

Next, in step S140, the CPU obtains the stoichiometric air-fuel ratio.

Next, in step S150, the CPU obtains the instructed injection amount.

Next, in step S160, the CPU calculates the difference between the actual injection amount and the instructed injection amount using the above equations (1) and (2) based on the intake air amount, the actual λ, the stoichiometric air-fuel ratio, and the instructed injection amount. Learn.

Next, in step S170, the CPU corrects the instructed injection amount based on the difference.

Next, in step S180, the CPU estimates the piston temperature based on the corrected instruction injection amount.

The control device 100 for an internal combustion engine according to the embodiment described above learns the difference between the actual injection amount of fuel injected by the fuel injection valves arranged corresponding to the cylinders of the engine and the instruction injection amount for the fuel injection valves. 20, a correction section 30 that corrects the instructed injection amount based on the learned difference, and a temperature estimation section 40 that estimates the piston temperature of the engine based on the corrected instructed injection amount.

With the above configuration, the commanded injection amount is corrected based on the learned difference, and the piston temperature is estimated based on the corrected commanded injection amount, so that the accuracy of the estimated piston temperature can be improved.

Further, in the internal combustion engine control device 100 according to the embodiment described above, the learning unit 20 is configured to calculate the intake air amount detected by the intake air amount sensor 2, the stoichiometric air-fuel ratio, the air-fuel ratio detected by the lambda sensor 3, and the instruction. The difference is learned based on the injection amount. This allows the difference to be learned reliably.

Further, in the internal combustion engine control device 100 according to the embodiment described above, the control unit 50 controls the engine exhaust temperature, the amount of change in the engine crank angular speed, and the temperature of the lubricating oil (oil temperature) supplied to the engine. Based on this, it is determined whether the intake air amount sensor 2 is normal, and if the intake air amount sensor 2 is normal, the learning unit 20 is controlled so that learning of the difference (learning value) is performed. As a result, learning of the difference is performed based on accurate detected values, so it is possible to suppress a decrease in accuracy of the estimated piston temperature.

Further, in the internal combustion engine control device 100 according to the embodiment described above, the control unit 50 controls the learning unit 20 so that learning of the difference is performed when the engine is operated under stable conditions. Thereby, learning of the difference is performed efficiently, so that it is possible to improve the effectiveness of learning by the learning section 20.

In the above embodiment, the control unit 50 determines whether the intake air amount sensor 2 is normal based on the engine exhaust temperature, the amount of change in the engine crank angular speed, and the lubricating oil supplied to the engine. However, the present disclosure is not limited to this, and may be performed based on any one of the exhaust temperature, the amount of change in crank angular velocity, and the oil temperature, for example.

Further, in the embodiment described above, it may be determined whether the intake air amount sensor 2 is normal or not based on the temperature of the cooling water supplied to the engine. Note that the temperature of the cooling water supplied to the engine is detected, for example, by a water temperature sensor that is provided near the outlet of a water jacket (not shown) and detects the temperature of the cooling water flowing from the water jacket into the flow path.

In addition, the above-mentioned embodiments are merely examples of implementation of the present disclosure, and the technical scope of the present disclosure should not be interpreted to be limited by them. . That is, the present disclosure can be implemented in various forms without departing from the gist or main features thereof.

INDUSTRIAL APPLICATION This disclosure is suitably utilized for the apparatus required to improve the precision of piston temperature estimation.

1 Internal combustion engine system 2 Intake air amount sensor 3 Lambda sensor 4 Exhaust temperature sensor 5 Crank angle sensor 6 Oil temperature sensor 7 Accelerator opening sensor 10 Acquisition section 20 Learning section 30 Correction section 40 Temperature estimation section 50 Control section 100 Internal combustion engine control device

Claims (5)

a learning unit that learns a difference between an actual injection amount of fuel injected by a fuel injection valve arranged corresponding to a cylinder of the internal combustion engine and an instruction injection amount for the fuel injection valve;
a storage unit that stores the difference as a learned value for each region divided by engine speed and fuel injection amount;
a correction unit that corrects the instructed injection amount based on the difference as a learning value stored in the storage unit ;
a temperature estimation unit that estimates a piston temperature of the internal combustion engine based on the corrected instructed injection amount and the engine rotation speed ;
Equipped with
The learning unit further includes, based on the detected value of the intake air amount detected by the intake air amount sensor, the stoichiometric air-fuel ratio, the actual value of the air-fuel ratio detected by the lambda sensor, and the instructed injection amount, learning the difference;
The learning unit further averages the actual value of the air-fuel ratio, averages the calculated value of the air-fuel ratio calculated based on the detected value of the intake air amount and the instructed injection amount, and calculates the averaged value of the air-fuel ratio. calculating the difference using the actual value of the fuel ratio and the calculated value of the air-fuel ratio ;
Internal combustion engine control device. a control unit that controls the learning unit so that learning of the difference is performed when the intake air amount sensor is normal;
A control device for an internal combustion engine according to claim 1. The control unit determines whether the intake air amount sensor is normal based on at least one of the exhaust gas temperature of the internal combustion engine, the amount of change in the crank angular velocity of the internal combustion engine, and the temperature of lubricating oil supplied to the internal combustion engine. determine whether there is
A control device for an internal combustion engine according to claim 2. comprising a control unit that controls the learning unit so that learning of the difference is performed when the internal combustion engine is operated under stable conditions;
A control device for an internal combustion engine according to claim 2 or 3. internal combustion engine;
A control device for an internal combustion engine according to any one of claims 1 to 4 is provided.
Internal combustion engine system.

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