JP2006207456A - Temperature estimating device for cylinder block in vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately estimate the temperature of cooling water in a cylinder block. <P>SOLUTION: An engine ECU executes a program including a step (S108) of detecting a tank water temperature THW(1) based on a signal transmitted from a heat storage tank outlet temperature sensor when cooling water (warm water) in the heat storage tank is supplied to an engine (Yes in S100) and when a supply destination of the cooling water is only the cylinder block (Yes in S102), and a step (S110) of estimating the water temperature THW(2) in the cylinder block based on the detected tank water temperature THW(1). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle control device equipped with a heat storage system that temporarily stores a liquid medium in a heat-retaining state, and in particular, supplies a high-temperature liquid medium to an internal combustion engine or supplies a low-temperature liquid medium to an internal combustion engine. The present invention relates to a cylinder block temperature estimation device in a vehicle for controlling the temperature of an internal combustion engine.

  When an internal combustion engine mounted in an automobile or the like is started in a cold state, the wall surface temperature of the intake port, the combustion chamber, etc. becomes low, so that it is difficult for the fuel to atomize and flame extinguishing occurs at the periphery of the combustion chamber This will cause a decrease in startability and a deterioration in exhaust emission.

  In order to solve such problems, a water-cooled internal combustion engine is provided with a heat storage device that retains high-temperature cooling water, and the internal combustion engine is supplied with cooling water stored in the heat storage device when the internal combustion engine is started. Techniques have been proposed to increase the temperature of the engine, thereby improving startability and speeding up warm-up.

  For example, an internal combustion engine provided with a heat storage device disclosed in Japanese Patent Application Laid-Open No. 2003-184553 (Patent Document 1) is formed in a cylinder head of the internal combustion engine, and a heat medium flow passage through which a heat medium flows, and a heat medium flow A heat storage device that retains and stores a part of the heat medium flowing through the passage, a first heat medium passage that guides the heat medium from the heat storage device to the heat medium flow passage, and a second that guides the heat medium from the heat medium flow passage to the heat storage device And a passage switching means for selectively conducting the first heat medium passage and the second heat medium passage.

According to the internal combustion engine provided with this heat storage device, the passage switching means causes the first heat medium passage to conduct, so that the high-temperature heat medium stored in the heat storage device through the first heat medium passage passes through the first heat medium passage. While being directly supplied to the heat medium flow passage, the passage switching means causes the second heat medium passage to conduct, so that the high-temperature heat medium in the heat medium flow passage directly passes through the second heat medium passage. Is supplied to the heat storage device. When the heat medium is directly exchanged between the heat medium flow passage and the heat storage device in this way, heat loss when supplying the heat medium from the heat storage device to the heat medium flow passage is minimized. At the same time, heat loss when supplying the heat medium from the heat medium flow path to the heat storage device is also minimized. As a result, even when the heat medium in the heat medium flow passage has a small amount of heat, the small amount of heat is efficiently stored in the heat storage device.
JP 2003-184553 A

  In the internal combustion engine provided with the heat storage device disclosed in Patent Document 1, the temperature of the internal combustion engine is increased by the high-temperature cooling water in the heat storage device, and the wall surface temperature of the intake port and the combustion chamber is increased. At this time, the sliding resistance between the cylinder and the piston can be reduced, and the temperature of the lubricating oil (engine oil) circulated for cooling the internal combustion engine can be increased at the same time. The viscosity of the lubricating oil varies greatly depending on the temperature. If the temperature of the lubricating oil is low, the viscosity increases and the sliding resistance increases. Therefore, it is desirable to raise the temperature of the lubricating oil to an appropriate temperature. However, merely supplying the high-temperature cooling water in the heat storage device to the internal combustion engine cannot always control the wall surface temperature of the intake port and the combustion chamber and the temperature of the lubricating oil at an appropriate temperature at the same time. Therefore, for example, when the wall surface temperature of the intake port or the combustion chamber is sufficiently increased and the temperature of the lubricating oil is insufficient, the high-temperature cooling water in the heat storage device is supplied only to the cylinder block of the internal combustion engine. It is possible to supply.

  However, in the internal combustion engine provided with the heat storage device disclosed in Patent Document 1, a water temperature sensor is provided on the cooling water passage connected to the cylinder head. Therefore, when the high temperature cooling water in the heat storage device is supplied only to the cylinder block, even if the temperature of the cooling water in the cylinder block rises due to the high temperature cooling water, the temperature of the cooling water in the cylinder block is not known. There was a problem.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a temperature estimation device capable of accurately estimating the temperature of a liquid medium (cooling water) in a cylinder block. It is to be.

  A temperature estimation device according to a first aspect of the invention estimates the temperature of a cylinder block in a vehicle equipped with storage means for storing a part of a liquid medium circulating in a flow path provided in an internal combustion engine. This temperature estimation device includes a circulation means for circulating the liquid medium in the storage means between at least one of the storage means, the cylinder head and the cylinder block of the internal combustion engine, and the temperature of the liquid medium in the storage means. When the liquid medium in the storage means is circulated between the cylinder blocks and the circulation between the cylinder heads is suppressed, the cylinder is determined based on the temperature of the liquid medium in the storage means. Estimating means for estimating the temperature of the liquid medium in the block.

  According to the first invention, when the liquid medium in the storage means is circulated between the cylinder blocks and the circulation between the cylinder heads is suppressed, the temperature in the cylinder block is determined based on the temperature of the liquid medium in the storage means. The temperature of the liquid medium is estimated. Thereby, even in an internal combustion engine in which a water temperature sensor is provided in the vicinity of the liquid medium outlet from the cylinder head, the temperature of the liquid medium in the cylinder block can be accurately estimated. Therefore, it is possible to provide a temperature estimation device that can accurately estimate the temperature of the liquid medium (cooling water) in the cylinder block.

  In the temperature estimation device according to the second invention, in addition to the configuration of the first invention, the estimation means includes means for estimating the temperature of the liquid medium in the cylinder block lower than the temperature of the liquid medium in the storage means. Including.

  According to the second invention, the temperature of the liquid medium supplied from the storage means to the cylinder block is lowered by heat exchange with the cylinder block. Therefore, the temperature of the liquid medium in the cylinder block is estimated to be lower than the temperature of the liquid medium in the storage unit. Thereby, the temperature of the liquid medium in the cylinder block can be accurately estimated.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

<First Embodiment>
With reference to FIG. 1, the control block diagram of the thermal storage system which is a control object of the control apparatus concerning this Embodiment is shown.

  The heat storage system shown in FIG. 1 is applied to a vehicle equipped with an internal combustion engine (engine). This vehicle may be a vehicle equipped only with an engine or a hybrid vehicle equipped with an engine and a motor driven by a battery.

  The vehicle is also equipped with an idling stop system. The idling stop system automatically stops the engine when the vehicle stops at a red light at an intersection or the like, and restarts the engine when the driver operates to start running again. For example, the accelerator opening is 0, 1 second or more has elapsed after the shift operation, the vehicle speed is 0, the engine speed is 1000 rpm or less, and the vehicle stops on the uphill or downhill road. If the engine coolant temperature is within a predetermined range, idling stop is permitted and the engine is temporarily stopped. In addition, you may mount the thermal storage system which concerns on this Embodiment in the vehicle in which the idling stop system is not mounted.

  As shown in FIG. 1, this heat storage system keeps a part of cooling water flowing through a cooling water flow path provided in a cylinder head (hereinafter referred to as a head) 100 and a cylinder block 110 in a heat storage tank 310. The cooling water is stored and supplied to the head 100 and the cylinder block 110 from the heat storage tank 310 as necessary. Cooling water is circulated by the mechanical water pump 200 between the head 100 and the cylinder block 110 and the radiator 400 or the radiator bypass passage 410. The flow rate control valve 430 controls which of the radiator 400 and the radiator bypass passage 410 passes through.

  Cooling water is supplied from the heat storage tank 310 to the head 100 and / or the cylinder block 110 by the electric water pump 300. By driving the electric water pump 300, the cooling water (hot water or cold water) in the heat storage tank 310 is supplied to the head 100 and / or the cylinder block 110 or the like via the three-way valve 600. The three-way valve 600 has four states: a fully closed state, a fully open state (port A, port B and port C are in communication), port A and port B are in communication, and port A and port C are in communication. Can be realized.

  Further, as temperature sensors of this heat storage system, an engine coolant temperature sensor 120 provided on the coolant outlet side of the head 100, a heat storage tank outlet temperature sensor 320 provided on the outlet side of the heat storage tank 310, and a radiator 400 A radiator outlet water temperature sensor 420 provided at the outlet is provided. Signals from these temperature sensors are input to an engine ECU (Electronic Control Unit) 1000.

  Engine ECU 1000 controls electric water pump 300, three-way valve 600, and flow control valve 430. The flow rate control valve 430 can control the flow rate of the cooling water flowing through the radiator 400 and the flow rate of the cooling water flowing through the radiator bypass passage 410 by changing the control duty. At this time, the flow rate control valve 430 can flow cooling water only to the radiator 400, only to the radiator bypass passage 410, and to the radiator 400 and the radiator bypass passage 410. When the flow control valve 430 receives a fully open command signal from the engine ECU 1000, the flow control valve 430 controls the flow rate so that the entire amount of cooling water flows to the radiator 400. Further, when the flow control valve 430 receives a full-close command signal from the engine ECU 1000, the flow control valve 430 controls the flow rate so that the entire amount of cooling water flows through the radiator bypass passage 410. Further, the flow control valve 430 can receive a command signal from the engine ECU 1000 and control the flow rate so that a part of the cooling water flows to the radiator 400 and the remaining cooling water flows to the radiator bypass passage 410. .

Further, engine ECU 1000 can control the discharge rate of electric water pump 300 by changing the control duty of the motor that drives electric water pump 300 to control the number of rotations of the motor. This control may be performed by making the voltage of the motor of the electric water pump 300 variable. Further, by changing the energization time of the motor of the electric water pump 300, the drive time of the electric water pump 300 is controlled to control the total amount of cooling water discharged from the electric water pump 300. Good.

  The supply destination of the cooling water in the heat storage tank 310 is, for example, the engine water temperature detected by the engine cooling water temperature sensor 120, the tank water temperature detected by the heat storage tank outlet temperature sensor 320, and the engine oil temperature (oil temperature) as parameters. It is determined by the 3D map it has. Instead of the tank water temperature, a temperature difference between the tank water temperature and the engine water temperature may be used as a parameter.

  The oil temperature is estimated from the engine water temperature. The method for estimating the oil temperature from the engine water temperature may be performed by using a known general technique, and therefore detailed description thereof will not be repeated here. Instead of estimating the oil temperature, it may be directly detected by a sensor or the like.

  For example, when the engine water temperature is lower than the threshold value TW and the oil temperature is lower than the threshold value TO, the cooling water (hot water) in the heat storage tank 310 is supplied to both the head 100 and the cylinder block 110. .

  When the engine water temperature is lower than the threshold value TW and the oil temperature is higher than the threshold value TO, the cooling water (hot water) in the heat storage tank 310 is supplied only to the head 100. When the engine water temperature is higher than the threshold value TW and the oil temperature is lower than the threshold value TO, the cooling water (hot water) in the heat storage tank 310 is supplied only to the cylinder block 110.

  When the engine water temperature is higher than the threshold value TW and the oil temperature is higher than the threshold value TO, the cooling water (hot water) in the heat storage tank 310 is not supplied to both the head 100 and the cylinder block 110.

  A control structure of a program executed by engine ECU 1000 that controls the heat storage system according to the embodiment of the present invention will be described with reference to FIG. The program described below is executed, for example, when an idling stop condition is satisfied and the engine is temporarily stopped.

  In step (hereinafter, step is abbreviated as S) 100, engine ECU 1000 determines whether or not the cooling water in heat storage tank 310 is supplied to at least one of head 100 and cylinder block 110. Whether or not the cooling water in the heat storage tank 310 is supplied to at least one of the head 100 and the cylinder block 110 is determined based on, for example, a three-dimensional map stored in a memory. When the cooling water in heat storage tank 310 is supplied to at least one of head 100 and cylinder block 110 (YES in S100), the process proceeds to S102. If not (NO in S100), this process ends.

  In S102, engine ECU 1000 determines whether cooling water in heat storage tank 310 is supplied to only cylinder block 110 of head 100 or cylinder block 110 or not. Whether or not the cooling water in the heat storage tank 310 is supplied only to the cylinder block 110 is determined based on, for example, a three-dimensional map stored in a memory. When cooling water in heat storage tank 310 is supplied only to cylinder block 110 (YES in S102), the process proceeds to S104. If not (NO in S102), this process ends.

  In S104, engine ECU 1000 brings port A and port C of three-way valve 600 into communication and puts port B in a shut-off state. In S106, engine ECU 1000 drives electric water pump 300.

  In S108, engine ECU 1000 detects tank water temperature (cooling water temperature in heat storage tank 310) THW (1) based on the signal transmitted from heat storage tank outlet temperature sensor 320.

  In S110, engine ECU 1000 estimates water temperature THW (2) in cylinder block 110 based on tank water temperature THW (1). The water temperature THW (2) in the cylinder block 110 is, for example, an experiment using the tank water temperature THW (1) and the total discharge amount of cooling water from the electric water pump 300 (or the driving time of the electric water pump 300) as parameters. Is estimated based on a map created in advance.

  At this time, if the cooling water in the heat storage tank 310 is hot water, the temperature of the cooling water discharged from the heat storage tank 310 decreases due to heat exchange with the cylinder block 110. Therefore, the water temperature THW (2) is estimated to be lower than the tank water temperature THW (1). Note that the method for estimating the water temperature THW (2) in the cylinder block 110 is not limited to this. When the cooling water in the heat storage tank 310 is cold water, the water temperature THW (2) may be estimated to be higher than the tank water temperature THW (1).

  An operation of the heat storage system according to the present embodiment based on the above-described structure and flowchart will be described.

  When the idling stop condition is satisfied and the engine is temporarily stopped, for example, when the driver removes his / her foot from the brake pedal and depresses the accelerator pedal, the engine is restarted. At this time, it is determined whether or not the cooling water (warm water) in the heat storage tank 310 is supplied to the engine in order to improve the startability of the engine or suppress the friction loss in the cylinder (S100).

  When cooling water (hot water) in heat storage tank 310 is supplied to the engine (YES in S100), it is determined whether only cylinder block 110 is present (S102). Here, it is assumed that cooling water is supplied only to cylinder block 110 (YES in S102).

  In this case, the port A and the port C of the three-way valve 600 are communicated, the port B is shut off (S104), and the electric water pump 300 is driven (S106). Thereby, the cooling water in the heat storage tank 310 is supplied only to the cylinder block 110. At this time, the cooling water discharged from the electric water pump 300 passes through the heat storage tank 310, the three-way valve 600, the cylinder block 110, and the mechanical water pump 200.

  Therefore, the cooling water in the heat storage tank 310 is circulated without being supplied to the head 100. However, the engine coolant temperature sensor 120 is provided on the coolant outlet side of the head 100. Therefore, the engine coolant temperature sensor 120 cannot detect the water temperature in the cylinder block 110.

  Therefore, the tank water temperature THW (1) is detected based on the signal transmitted from the heat storage tank outlet temperature sensor 320 (S108), and the water temperature THW (2) in the cylinder block 110 is based on the tank water temperature THW (1). Is estimated (S110). Thereby, the water temperature THW (2) in the cylinder block 110 can be obtained. The estimated water temperature THW (2) is used for engine control such as idling stop permission conditions and engine warm-up determination. Therefore, the engine can be controlled with high accuracy.

  As described above, the engine ECU of the heat storage system according to the present embodiment, when cooling water (hot water) is supplied from the heat storage tank only to the cylinder block, based on the tank water temperature THW (1), Estimate the water temperature THW (2). Thereby, even in an engine in which an engine water temperature sensor is provided on the coolant outlet side of the head, the water temperature THW (2) in the cylinder block can be accurately estimated.

  In the present embodiment, the idling stop condition is satisfied and the engine is started (restarted) from a state where the engine is temporarily stopped, and the ignition switch is changed from the off state to the on state. When starting the engine, the water temperature THW (2) in the cylinder block may be estimated based on the tank water temperature THW (1).

<Second Embodiment>
Hereinafter, a control block diagram of another heat storage system that can be used in common with FIG. 2 will be described.

  As shown in FIG. 3, this heat storage system is also controlled by engine ECU 1000, as in the first embodiment described above. A difference from the control block diagram shown in FIG. 1 is the position of the three-way valve 610.

  This three-way valve 610 is in a fully closed state, a fully open state (port A, port B and port C are in communication), port A and port B are in communication, port A and port C are in communication, port B and port Five states of communication with C can be realized. The position of the three-way valve 610 is different from that of the three-way valve 600 of FIG. 1 described in the first embodiment.

  In such a heat storage system shown in FIG. 3, the cooling water in the heat storage tank 310 can be supplied to both the head 100 and the cylinder block 110, or can be supplied only to the cylinder head 110. Also in the heat storage system shown in FIG. 3, the water temperature THW (2) in the cylinder block 110 can be accurately estimated by executing the program represented by the flowchart shown in FIG.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a control block diagram of the heat storage system which concerns on the 1st Embodiment of this invention. It is a figure which shows the flowchart which shows the control structure of the program performed by engine ECU of FIG. It is a control block diagram of the heat storage system which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

  100 Cylinder Head, 110 Cylinder Block, 120 Engine Cooling Water Temperature Sensor, 200 Mechanical Water Pump, 300 Electric Water Pump, 310 Thermal Storage Tank, 320 Thermal Storage Tank Outlet Temperature Sensor, 400 Radiator, 410 Radiator Bypass Path, 420 Radiator Outlet Water Temperature Sensor, 430 Flow control valve, 500 Heater core, 610 Three-way valve, 1000 Engine ECU.

Claims (2)

A temperature estimation device for a cylinder block in a vehicle equipped with a storage means for storing a part of a liquid medium circulating in a flow path provided in an internal combustion engine.
A circulation means for circulating the liquid medium in the storage means between the storage means and at least one of a cylinder head and a cylinder block of the internal combustion engine;
Detection means for detecting the temperature of the liquid medium in the storage means;
When the liquid medium in the storage means is circulated between the cylinder blocks and the circulation between the cylinder heads is suppressed, the liquid medium in the cylinder block is based on the temperature of the liquid medium in the storage means. And a temperature estimation device.   The temperature estimation device according to claim 1, wherein the estimation unit includes a unit for estimating a temperature of the liquid medium in the cylinder block lower than a temperature of the liquid medium in the storage unit.

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