JP6154159B2 - Flow control device, flow control method - Google Patents

Description

  The present invention relates to a flow rate control device and a flow rate control method for controlling a flow rate of a fluid related to temperature control.

  2. Description of the Related Art Conventionally, a technique for controlling the flow rate of cooling water for cooling an engine is known for the purpose of controlling the temperature of an internal combustion engine such as an engine. The cooling water is circulated through the vicinity of the engine via the main path that passes through the radiator that cools the cooling water or the bypass path that does not pass through the radiator, and is cooled when passing through the main path, resulting in the temperature of the engine. Reduce. Further, the engine temperature is controlled by adjusting the flow rate of the cooling water to the main path or the bypass path by a valve. In such an engine cooling system, the flow rate of the cooling water to be introduced into the main path or the bypass path is determined as the target flow rate based on the difference between the target engine temperature and the measured engine temperature. The Further, a valve for adjusting the flow rate of the cooling water is controlled based on the target flow rate.

  In such an engine cooling system, there is a problem that the controllability of the engine temperature control is deteriorated in all situations due to the shortage or excess of the flow rate. In order to prevent the temperature of the engine from decreasing after the warm-up operation is completed, a stepping motor is used to switch the valve between different modes with different control methods for the flow rate of the cooling water. In controlling the flow rate of the cooling water to be driven, a technique for controlling the valve operating speed based on the engine speed and the intake pressure is known (see, for example, Patent Document 1).

JP 2002-74461 A

  However, the above-described technology merely reduces the rotation speed of the stepping motor when shifting to a different mode and prevents the engine temperature from falling, and the engine constantly fluctuates due to factors such as the driving conditions of the driver. It cannot cope with the load. Therefore, overshoot or undershoot occurs, and there is a problem that the controllability deteriorates in a situation where the state of the engine fluctuates.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a flow rate control device and a flow rate control method capable of improving the controllability of the engine temperature in a situation where the engine state fluctuates. And

  In order to solve the above-described problem, one aspect of the present invention is a flow rate control device that controls the flow rate of cooling water that cools an internal combustion engine, the measured temperature being the measured temperature of the internal combustion engine, a target, A feedback flow rate calculation unit that calculates a feedback flow rate by feedback control based on a control deviation from a target temperature that is the temperature of the internal combustion engine, an internal combustion engine rotational speed that is the rotational speed of the internal combustion engine, and a manifold of the internal combustion engine By correcting the feedback flow rate based on the feed forward flow rate based on the feed forward flow rate calculation unit that calculates the feed forward flow rate based on the pressure and the radiator temperature that is the temperature of the radiator that cools the cooling water, A target flow rate calculation unit that calculates a target flow rate that is a target flow rate.

  ADVANTAGE OF THE INVENTION According to this invention, in control of the valve which adjusts the flow volume of fluid, the controllability of the engine temperature in the situation where an engine state fluctuates can be improved.

It is a figure which shows the engine cooling system which concerns on this Embodiment. It is a figure which shows the hardware constitutions of ECU. It is a figure which shows the function structure of a valve control apparatus. It is a flowchart which shows operation | movement of a feedforward flow volume calculation part.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, the engine cooling system according to the present embodiment will be described. FIG. 1 is a diagram showing an engine cooling system according to the present embodiment.

  As shown in FIG. 1, the engine cooling system 1 according to the present embodiment includes an engine 11, a water jacket 12, a water pump 13, a cooling water valve 21, a motor 22, a position sensor 23, a first water temperature sensor 24, and a second water temperature sensor. A water temperature sensor 25, an ECU (Engine Control Unit) 31, a radiator 41, a heater 42, a throttle 43, a main passage pipe 91, a sub passage pipe 92, and a bypass passage pipe 93 are provided.

  The engine cooling system 1 circulates cooling water through the main flow path pipe 91, the sub flow path pipe 92, or the bypass flow path pipe 93, and controls the temperature of the engine 11 by the water jacket 12.

  The engine 11 is an internal combustion engine of a vehicle such as an automobile. The water jacket 12 is provided in the vicinity of the engine 11 and cools the engine 11 with cooling water therein. The main flow path pipe 91 allows cooling water to flow into the radiator 41. The sub passage pipe 92 allows cooling water to flow into the heater 42 and the throttle 43. The bypass flow path pipe 93 allows the cooling water flowing out from the water jacket 12 to flow into the water pump 13. The cooling water that has flowed into the radiator 41, the heater 42, and the throttle 43 flows into the water pump 13. The water pump 13 allows cooling water to flow into the water jacket 12. The radiator 41 cools the cooling water. The heater 42 warms the passenger compartment. The throttle 43 controls the amount of intake air flowing into the engine 11.

  The cooling water valve 21 is a rotary valve, and an opening is provided in a part of the outer peripheral surface, and the cooling water flows into the main flow path pipe 91 and the sub flow path pipe 92 according to the opening degree. The motor 22 is a DC motor as an actuator that drives the cooling water valve 21. The position sensor 23 detects the opening degree of the cooling water valve 21 relative to the main flow path pipe 91 and the sub flow path pipe 92 by detecting the circumferential position of the cooling water valve 21. The first water temperature sensor 24 is installed near the outlet of the water jet 12 and detects the temperature of the cooling water flowing out of the water jacket 12 as the engine temperature. The second temperature sensor 25 is installed in the vicinity of the outlet of the radiator 41, and detects the temperature of the cooling water flowing out of the radiator 41 as the radiator temperature. The ECU 31 includes a processor and a memory, and is a microcontroller that controls various operations related to the engine 11. In this embodiment, the ECU 31 detects the engine temperature detected by the first water temperature sensor 24, the second water temperature sensor 25, and the position sensor 23. The operation of the motor 22 is operated based on the radiator temperature and the position of the cooling water valve 21.

  With the configuration described above, the cooling water is cooled by the radiator 41 by circulating through the main flow path pipe 91, and is circulated without being cooled when passing through the bypass flow path pipe 93. Further, the engine cooling system 1 controls the temperature of the engine 11 by switching the cooling water circulation path according to the opening degree of the cooling water valve 21 and controlling the amount of cooling water flowing into the main passage pipe 91. .

  Next, the hardware configuration of the ECU will be described. FIG. 2 is a diagram illustrating a hardware configuration of the ECU.

  As shown in FIG. 3, the ECU 31 includes a CPU (Central Processing Unit) 311, a RAM 312, a ROM 313, and an input / output interface 314. The CPU 311 and the RAM 312 cooperate to perform processing related to the control of the cooling water valve 21. The ROM 313 is a non-volatile memory that stores a radiator temperature table and a lookup table, which will be described later. The input / output interface 314 is an interface related to input / output of the CPU 311, and the CPU 311 acquires detection results by the position sensor 23, the first water temperature sensor 24, and the second water temperature sensor 25 through the input / output interface 314, A signal corresponding to the operation amount of the motor 22 is output to the drive circuit 25 via the input / output interface 313. The drive circuit 25 is a PWM circuit that controls the motor 22 by PWM (Pulse Width Modulation), and drives the motor 22 by changing the duty ratio of the pulse width according to the magnitude of the input signal.

  Next, the functional configuration of the flow control device will be described. FIG. 3 is a diagram illustrating a functional configuration of the flow control device.

  As shown in FIG. 3, the flow control device 5 includes a feedback flow rate calculation unit 51, a feedforward flow rate calculation unit 52, and a target flow rate calculation unit 53 as functions, and calculates a target flow rate that is a target flow rate. The valve control device 6 controls the opening degree of the cooling water valve 21 based on the target flow rate and the engine temperature. Note that these functions are realized by the cooperation of the CPU 311 and the RAM 312 described above. That is, in the present embodiment, the ECU 31 functions as the flow rate control device 5 and the valve control unit 6.

  The feedback flow rate calculation unit 51 calculates the feedback flow rate by PID control based on the target engine temperature, which is the target engine temperature, the engine temperature, and the radiator temperature. Specifically, the feedback flow rate is calculated based on the deviation between the target temperature and the engine temperature and gain scheduling based on the radiator temperature. This gain scheduling is executed by the radiator temperature table described above. This radiator temperature table associates a plurality of radiator temperatures with preset values set for these temperatures. That is, the feedback flow rate calculation unit 51 calculates the feedback flow rate by correcting the control amount based on the control deviation by the set value corresponding to the acquired radiator temperature.

  The feedforward flow rate calculation unit 52 calculates the feedforward flow rate based on the manifold pressure, the engine speed, and the radiator temperature. The specific operation of the feedforward flow rate calculation unit 52 will be described later.

  The target flow rate calculation unit 53 calculates the target flow rate by correcting the feedback flow rate based on the feedforward flow rate. Specifically, the target flow rate is calculated based on the feedback flow rate obtained by adding the feedforward flow rate and the integral element.

  Next, the operation of the feedforward flow rate calculation unit will be described. FIG. 4 is a flowchart showing the operation of the feedforward flow rate calculation unit. In the operation described below, it is assumed that the values of the engine speed and the manifold pressure are stored in the RAM 312 in advance.

  As shown in FIG. 4, first, the feedforward flow rate calculation unit 52 acquires the value of the engine speed from the RAM 31 (S101), and corrects the acquired value of the engine speed by filtering it with a phase advance compensation element. (S102).

  Further, the feedforward flow rate calculation unit 52 acquires a manifold pressure value from the RAM 31 (S103), and corrects the acquired manifold pressure value by filtering with a first-order lag element (S104).

  Further, the feedforward flow rate calculation unit 52 refers to the lookup table stored in the ROM 313 (S105). Here, the lookup table will be described. The look-up table associates preset values with each combination of a plurality of engine speeds and manifold pressures. The feedforward flow rate calculation unit 52 refers to the look-up table to obtain the corrected engine speed value and the set value corresponding to the manifold pressure value.

  Next, the feedforward flow rate calculation unit 52 corrects the set value acquired by referring to the lookup table by filtering with a phase advance compensation element (S106).

  Next, the feedforward flow rate calculation unit 52 acquires the value of the radiator temperature measured by the second water temperature sensor 25 (S107), and refers to the radiator temperature table (S108). Here, the feedforward flow rate calculation unit 52 acquires a set value corresponding to the acquired value of the radiator temperature by referring to the radiator temperature table.

  Next, the feedforward flow rate calculation unit 52 calculates the feedforward flow rate by multiplying the set value filtered by the phase advance compensation element and the set value acquired by referring to the radiator temperature table ( S109).

  As described above, the feedforward flow rate calculation unit 52 sets a value obtained by correcting the value based on the engine speed and the manifold pressure by the gain schedule based on the radiator temperature as the feedforward flow rate.

  As described above, the flow control device 5 according to the present embodiment treats changes in the engine speed, manifold pressure, and radiator temperature as disturbances, and cancels them with the feedforward flow rate. Thereby, the flow control device 5 can improve the controllability of the temperature of the water jacket 12 against the fluctuation of the engine 11. For example, according to the flow control device 5, even when the state of the engine 11 changes rapidly, the temperature change of the water jacket 12 can be reduced.

  Further, by filtering the engine speed, the manifold pressure, and the values based on them with a temporary delay element or a phase advance element, calibration according to the characteristics of the engine 11 can be performed.

  The present invention can be implemented in various other forms without departing from the gist or main features thereof. Therefore, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is shown by the scope of claims, and is not restricted by the text of the specification. Moreover, all modifications, various improvements, substitutions and modifications belonging to the equivalent scope of the claims are all within the scope of the present invention.

  DESCRIPTION OF SYMBOLS 1 Engine cooling system, 5 Flow control apparatus, 6 Valve control apparatus, 11 Engine, 12 Water jacket, 13 Water pump, 21 Cooling water valve, 22 Motor, 23 Position sensor, 24 1st water temperature sensor, 25 2nd water temperature sensor, 31 ECU, 41 Radiator, 42 Heater, 43 Throttle, 51 Feedback flow rate calculation unit, 52 Feed forward flow rate calculation unit, 53 Target flow rate calculation unit, 91 Main flow channel pipe, 92 Sub flow channel pipe, 93 Bypass flow channel pipe, 311 CPU, 312 RAM, 313 ROM, 314 I / O interface.

Claims (8)

A flow rate control device for controlling the flow rate of cooling water for cooling an internal combustion engine,
A feedback flow rate calculation unit that calculates a feedback flow rate by feedback control based on a control deviation between a measured temperature that is the measured temperature of the internal combustion engine and a target temperature that is a target temperature of the internal combustion engine;
Feedforward flow rate calculation for calculating a feedforward flow rate based on an internal combustion engine speed that is the rotational speed of the internal combustion engine, a manifold pressure of the internal combustion engine, and a radiator temperature that is a temperature of a radiator that cools the cooling water And
A target flow rate calculation unit that calculates a target flow rate that is a target flow rate by correcting the feedback flow rate based on the feedforward flow rate ,
The feedback flow rate calculation unit further calculates the feedback flow rate based on the radiator temperature . 2. The feedforward flow rate calculation unit according to claim 1, wherein the feedforward flow rate calculation unit calculates the feedforward flow rate by performing gain scheduling of a value based on the rotational speed of the internal combustion engine and the manifold pressure based on the radiator temperature. Flow control device. The flow rate control device according to claim 1, wherein the feedforward flow rate calculation unit calculates the feedforward flow rate based on a value obtained by correcting the rotational speed of the internal combustion engine by a phase advance compensation element. . The flow rate according to any one of claims 1 to 3, wherein the feedforward flow rate calculation unit calculates the feedforward flow rate based on a value obtained by correcting the manifold pressure with a first-order lag element. Control device. A flow rate control method for controlling the flow rate of cooling water for cooling an internal combustion engine,
A feedback flow rate is calculated by feedback control based on a control deviation between the measured temperature that is the measured temperature of the internal combustion engine and the target temperature that is the target temperature of the internal combustion engine,
Based on the internal combustion engine rotational speed that is the rotational speed of the internal combustion engine, the manifold pressure of the internal combustion engine, and the radiator temperature that is the temperature of the radiator that cools the cooling water, the feedforward flow rate is calculated,
The computer executes a target flow rate that is a target flow rate by correcting the feedback flow rate based on the feedforward flow rate ,
The flow rate control method further comprising: calculating the feedback flow rate based on the radiator temperature . The flow rate control method according to claim 5 , wherein the feedforward flow rate is calculated by performing gain scheduling of a value based on the internal combustion engine speed and the manifold pressure based on the radiator temperature. Flow control method according to claim 5 or claim 6, and calculates the feedforward flow rate based on the value the corrected by the engine speed phase lead compensation element. The flow rate control method according to any one of claims 5 to 7 , wherein the feedforward flow rate is calculated based on a value obtained by correcting the manifold pressure with a first-order lag element.

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