JP2010242594A - Water pump control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water pump control device capable of preventing the local boiling of an internal combustion engine by accurately detecting a boiling state of cooling water for cooling the internal combustion engine. <P>SOLUTION: The water pump control device is provided with a controlling means 11 which determines whether the temperature of the cooling water in a cylinder head 110 estimated by adding a separation value to a measured value by a water temperature sensor 30 exceeds predetermined temperature or not when a water pump 20 is stopped, and rotates water pump 20 when determining that the temperature of the cooling water exceeds the predetermined temperature, as a result of the determination. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a water pump control device.

  In an internal combustion engine, a technique is known in which a water pump is stopped during warm-up to quickly complete warm-up and improve fuel efficiency. For example, in Patent Document 1, the electric water pump is stopped for a predetermined period when the internal combustion engine is cold-started, and the cooling water is intermittently circulated through the water jacket in the pulse control mode after the stop. It is disclosed to suppress partial boiling of cooling water accompanying a local temperature rise.

JP 2006-214280 A

  By the way, the boiling state of the cooling water for cooling the internal combustion engine is managed by a water temperature sensor. Many of the water temperature sensors are provided in the cylinder block. When the convection and circulation of the cooling water are stopped by stopping the water pump, there is a large difference between the water temperature in the cylinder head and the water temperature measured by the water temperature sensor of the cylinder block.

  The coolant temperature in the cylinder head tends to be higher than the coolant temperature in the cylinder block when the circulation of the coolant is stopped. For this reason, even if the cooling water in the cylinder head is in a boiling state, if the rotation / stop of the water pump is controlled by the cooling water temperature in the cylinder block, the boiling state of the cooling water may not be detected accurately.

  This invention is made in view of such a situation, and provides the water pump control apparatus which can prevent the local boiling of an internal combustion engine by detecting correctly the boiling state of the cooling water which cools an internal combustion engine. For the purpose.

In order to solve this problem, the water pump control device of the present invention is such that when the water pump is stopped, the coolant temperature in the cylinder head estimated by adding a deviation value to the measured value by the water temperature sensor is equal to or higher than a predetermined temperature. It is a water pump control device having a control means for rotating the water pump when it is determined that the temperature is equal to or higher than a predetermined temperature as a result of the determination.
According to this configuration, since the coolant temperature in the cylinder head is accurately estimated based on the measured value and the deviation value by the water temperature sensor, the coolant convects, so that partial boiling in the cylinder head can be prevented. .

Further, the water pump control device of the present invention is characterized in that the control means makes a determination based on a deviation value based on a fuel injection amount.
According to this configuration, since the coolant temperature in the cylinder head is accurately estimated based on the measured value by the water temperature sensor and the fuel injection amount, the coolant convects, thereby preventing partial boiling in the cylinder head. it can.

  ADVANTAGE OF THE INVENTION According to this invention, the local boiling of an internal combustion engine can be prevented by detecting correctly the boiling state of the cooling water which cools an internal combustion engine, and it can suppress overheating and the injection of LLC.

It is a figure which illustrates the relationship between an internal combustion engine and a water pump. It is a flowchart which illustrates cooling of an internal combustion engine. It is a graph which illustrates the relationship between the amount of fuel injection, and a deviation value.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram illustrating the relationship between an internal combustion engine and a water pump.
As shown in FIG. 1, the internal combustion engine 100 includes a cylinder head 110, a cylinder block 120, and a water temperature sensor 30.

  A water jacket 121 is provided inside the cylinder head 110 and the cylinder block 120. Cooling water circulates inside the water jacket 121. Circulation is performed by an electric water pump 20. Thereby, the internal combustion engine 100 is cooled.

  The water temperature sensor 30 is provided in the cylinder block 120 and detects the temperature of cooling water that convects the inside of the water jacket 121 in the cylinder block 120. The detected water temperature is sent to a control means 11 of an ECU (Engine Control Unit) 10. The control means 11 controls rotation / stop of the water pump 20 according to the received water temperature. When the water pump 20 rotates, the cooling water convects the internal combustion engine 100. The ECU 10 is a hardware device that includes a CPU, a RAM, a ROM, and the like.

  FIG. 2 is a flowchart illustrating the cooling of the internal combustion engine, and FIG. 3 is a graph illustrating the relationship between the fuel injection amount and the deviation value.

  First, as shown in FIG. 2, the control means 11 of the ECU 10 determines whether or not there is a request for stopping the cooling water (step S1). This determination process is performed, for example, by determining whether warm-up has been started. The warm-up start determination may be made by determining whether or not the internal combustion engine has been operated.

  When it is determined in the process of step S1 that the cooling water has been requested to stop (step S2), the control unit 11 then determines whether or not the cooling water temperature in the cylinder head 110 is 120 ° C. or less (step S2). Step S3). Note that 120 ° C., which is the threshold for determination, may be changed to 110 ° C., 130 ° C., or the like as appropriate through experiments.

  As described above, the coolant temperature is detected by the water temperature sensor 30. However, since the water temperature sensor 30 is provided in the cylinder block 120, the coolant temperature in the cylinder head 110 cannot be directly measured. For this reason, the ECU 10 estimates the coolant temperature in the cylinder head 110 by estimation.

  According to the graph shown in FIG. 3, the difference value ΔT between the coolant temperature in the cylinder head 110 and the measured value by the coolant temperature sensor 30 in the cylinder block 120 is calculated based on the fuel injection amount and the rotational speed of the internal combustion engine 100. . For example, the divergence value ΔT tends to increase in the graph in which the engine speed is 3000 rpm than in the graph in which the engine speed is 1400 rpm.

Further, according to this graph, it is understood that the deviation value ΔT is a linear function of the fuel injection amount and the deviation value ΔT if the engine speed is fixed. For example, when the engine speed is 2600 rpm, the deviation value ΔT increases as the fuel injection amount increases. For this reason, the deviation value ΔT can be expressed by the following equation.
ΔT = a × fuel injection amount + b (where a and b are values determined by experiments)

Therefore, it is estimated that the temperature of the cooling water in the cylinder head 110 is a temperature obtained by adding the deviation value ΔT to the measured value of the water temperature sensor 30.
Since the fuel injection amount is proportional to the exhaust gas temperature, the exhaust gas temperature may be used instead of the fuel injection amount. The measurement of the exhaust gas temperature may be a measurement value by a sensor or a value calculated based on the fuel injection amount.

  Returning to FIG. 2, when it is determined in step S2 that the coolant temperature in the cylinder head 110 is 120 ° C. or lower, the control unit 11 stops the rotation of the water pump 20 (step S3). That is, it is determined that the coolant temperature in the cylinder head 110 is not in a boiling state.

  Next, the control means 11 determines whether the cylinder head is 120 ° C. or higher or the warm-up is completed with the water pump 20 stopped (step S4). The coolant temperature in the cylinder head 110 can be determined by the determination method in step S2.

  Here, when the control unit 11 determines that the cylinder head is 120 ° C. or higher or the warm-up is completed, the water pump 20 is rotated. That is, there is a possibility that partial boiling has occurred in the cooling water in the cylinder head 110, and in order to cool this, the water pump 20 is rotated to convect the cooling water.

  As a result, local boiling in the cylinder head 110 can be prevented, and overheating of the internal combustion engine 100 and injection of LLC (antifreeze liquid) can be prevented. In particular, since the water pump 20 is stopped, the cooling water of the internal combustion engine 100 circulates by natural convection. Conventionally, in the cylinder head 110, a time difference has occurred until the water temperature sensor 30 measures the cooling water in which partial boiling has occurred. However, according to the present invention, the time difference does not occur and the water temperature sensor 30 The temperature of the cooling water in the cylinder head 110 can be estimated from the measured value, and the partial boiling state can be managed.

  As described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

10 ECU
DESCRIPTION OF SYMBOLS 11 Control means 20 Water pump 30 Water temperature sensor 100 Internal combustion engine 110 Cylinder head 120 Cylinder block 121 Water jacket

Claims (2)

When the water pump is stopped, it is determined whether or not the coolant temperature in the cylinder head estimated by adding a deviation value to the measured value by the water temperature sensor is equal to or higher than a predetermined temperature. A water pump control device having control means for rotating the water pump when it is determined that   The water pump control device according to claim 1, wherein the control unit determines based on a deviation value based on a fuel injection amount.

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