JP4453633B2 - Heat storage device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique capable of accumulating quickly heat in a heat accumulator, in the heat accumulator of an internal combustion engine. <P>SOLUTION: The technique is provided with a pump 12 for circulating cooling water for the internal combustion engine 1, and capable of changing a flow rate of the cooling water, heat accumulator 20 for accumulating the heat by accumulating the cooling water for the internal combustion engine 1, and a heat accumulation control means 14 for making the pump 12 operate, to introduce the cooling water into the heat accumulator 20, after a temperature of the cooling water is elevated by stopping the pump 12 while operating the internal combustion engine 1, before accumulating the heat in the heat accumulator 20. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a heat storage device for an internal combustion engine.

  Cooling water whose temperature has risen during operation of the internal combustion engine is stored in a heat storage tank, and the cooling water stored in the heat storage tank is flowed to the internal combustion engine at the next engine start so that quick warm-up can be completed. Can do. Since the high temperature coolant stored in the heat storage tank is consumed when the internal combustion engine is started, it is necessary to store the high temperature coolant again after the internal combustion engine is started. Here, if the operation time of the internal combustion engine is short, the temperature of the cooling water does not rise sufficiently, so that it is difficult to store heat in the heat storage tank.

And in what is equipped with a heat storage tank and a hybrid system, the technique of changing the stop condition of an internal combustion engine, ie, the condition to switch to motor drive, when it is necessary to store heat in the heat storage tank and when it is not so is known (For example, refer to Patent Document 1). According to this prior art, when it is necessary to store heat in the heat storage tank, the internal combustion engine is hardly stopped, so that the temperature of the cooling water can be increased quickly.
JP 2003-293769 A JP-A-8-183324

  Here, during operation of the internal combustion engine, the cooling water is also circulated to the outside of the internal combustion engine. Therefore, the temperature outside the internal combustion engine and the temperature of the cooling water flowing therethrough must be increased. That is, it takes time to raise the temperature of all the cooling water circulating through the internal combustion engine to a temperature that can be introduced into the heat storage device. Therefore, a quick increase in the cooling water temperature is desired.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a technique capable of storing heat in a heat storage device more quickly in a heat storage device of an internal combustion engine.

  In order to achieve the above object, a heat storage device for an internal combustion engine according to the present invention employs the following means.

That is,
A pump capable of circulating the cooling water of the internal combustion engine and changing the flow rate of the cooling water;
A heat storage device for storing heat by storing cooling water of the internal combustion engine;
Heat storage control means for operating the internal combustion engine and stopping the pump before storing heat in the heat storage device to raise the temperature of cooling water and then operating the pump to introduce cooling water into the heat storage device; ,
It is provided with.

By stopping the pump before storing heat in the heat storage device, the cooling water inside the internal combustion engine stays inside the internal combustion engine. Thereby, the cooling water inside the internal combustion engine can receive a lot of heat generated from the internal combustion engine, and the temperature is quickly raised. Thus, by operating the pump after raising the temperature of the cooling water inside the internal combustion engine, the high temperature cooling water staying inside the internal combustion engine can be introduced into the heat storage device. Therefore, heat can be stored in the heat storage device at an early stage. Thereby, it is possible to store heat in the heat storage device even when the operation time of the internal combustion engine is short.

  The present invention further includes a hybrid system having a motor, wherein the motor is operated so that the output of the internal combustion engine is equal to or less than a first predetermined value when the pump is stopped by the heat storage control means. it can.

  By stopping the pump, the temperature inside the internal combustion engine rises locally, and the cooling water may boil. Here, in the hybrid system, the wheels can be driven by using the output of the motor in an auxiliary manner. That is, by operating the motor when the load on the internal combustion engine becomes high, the output of the entire vehicle can be kept constant while reducing the load on the internal combustion engine. Thereby, since the amount of heat generated from the internal combustion engine can be reduced, it is possible to suppress an excessive increase in the cooling water temperature. And durability and reliability of an internal combustion engine can be improved.

  Here, the first predetermined value may be a maximum value of an output at which the internal combustion engine is not likely to overheat or a maximum value of an output at which the cooling water is not likely to boil.

  Furthermore, the present invention further includes a hybrid system having a motor, wherein the motor is operated so that the output of the internal combustion engine becomes equal to or higher than a second predetermined value when the pump is stopped by the heat storage control means. it can.

  When the load on the internal combustion engine is low, the output of the internal combustion engine is reduced and the amount of heat generated is also reduced. If the amount of heat generated from the internal combustion engine is small, a long time is required to raise the cooling water temperature. Here, in the hybrid system, the load of the internal combustion engine can be increased by using the motor as a generator. Note that the generator and the motor may be provided separately. Since the amount of heat generated from the internal combustion engine can be increased by increasing the load on the internal combustion engine by the motor, the cooling water temperature can be increased more quickly. Thereby, heat can be quickly stored in the heat storage device.

  The second predetermined value can be a minimum value of the output of the internal combustion engine that is necessary for storing heat in the heat storage device at an early stage.

  The heat storage device for an internal combustion engine according to the present invention can store heat in the heat storage device more quickly.

  Hereinafter, specific embodiments of a heat storage device for an internal combustion engine according to the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating a schematic configuration of a heat storage device for an internal combustion engine according to the present embodiment.

  The internal combustion engine 1 is a four-cycle engine and includes a cylinder head 2 and a cylinder block 3.

A water jacket 4 for circulating cooling water is formed inside the internal combustion engine 1. The internal combustion engine 1 is connected to a passage for circulating cooling water. The passage for circulating the cooling water includes a first circulation passage 6 that circulates through the radiator 5, a second circulation passage 8 that circulates through the heater core 7, and a third circulation passage 10 that circulates through the bypass passage 9. Yes. A part of each circulation passage has a portion shared with other circulation passages. For example, the water jacket 4 is included in all circulation passages.

  The first circulation passage 6 includes a radiator 5, a thermostat 11, an electric pump 12, and a water jacket 4. The thermostat 11 operates when the cooling water temperature becomes higher than the set temperature, and causes the cooling water to flow through the first circulation passage 6. When the cooling water temperature is low, the thermostat 11 causes the cooling water to flow through the third circulation passage 10. In addition, cooling water flows through the second circulation passage 8 regardless of the cooling water temperature.

  In the first circulation passage 6, the cooling water discharged from the electric pump 12 flows in the order of the water jacket 4, the radiator 5, and the thermostat 11.

  The second circulation passage 8 includes a heater core 7, an electric pump 12, a water jacket 4, a heat storage device 20, and a three-way valve 21. The three-way valve 21 is actuated by a signal from the ECU 14 described later, and causes cooling water to flow through either the heater core 7 or the heat storage device 20. The three-way valve 21 may be capable of changing the ratio of the cooling water flowing to the heater core 7 or the heat storage device 20.

  In the second circulation passage 8, the cooling water discharged from the electric pump 12 flows in the order of the water jacket 4, the heater core 7, and the three-way valve 21, or in the order of the water jacket 4, the heat storage device 20, and the three-way valve 21.

  The third circulation passage 10 includes a bypass passage 9, a thermostat 11, an electric pump 12, and a water jacket 4.

  In the third circulation passage 10, the cooling water discharged from the electric pump 12 flows in the order of the water jacket 4, the bypass passage 9, and the thermostat 11.

  Cooling water that outputs a signal corresponding to the temperature of the cooling water flowing in the first circulation passage 6 and the second circulation passage 8 near the outlet of the first circulation passage 6 and the second circulation passage 8 from the internal combustion engine 1. A temperature sensor 13 is attached. Since the cooling water temperature sensor 13 is mounted near the bypass passage 9, the cooling water temperature obtained by the cooling water temperature sensor 13 (hereinafter referred to as detected water temperature) is the cooling water flowing through the bypass passage 9. It also shows the temperature.

  The internal combustion engine 1 configured as described above is provided with an ECU 14 that is an electronic control unit for controlling the internal combustion engine 1. The ECU 14 is a unit that controls the operation state of the internal combustion engine 1 in accordance with the operation conditions of the internal combustion engine 1 and the request of the driver.

  In addition to the coolant temperature sensor 13, the ECU 14 includes an accelerator opening sensor 15 that outputs a signal corresponding to the accelerator opening, that is, the engine load, and a crank position sensor 16 that outputs a signal corresponding to the rotational speed of the internal combustion engine 1. Connected via wiring, the output signals of these sensors are input to the ECU 14.

  On the other hand, the electric pump 12 and the three-way valve 21 are connected to the ECU 14 via electric wiring, and the ECU 14 controls the electric pump 12 and the three-way valve 21. The electric pump 12 can adjust the discharge amount of the cooling water, that is, the flow rate of the cooling water, by adjusting the power supplied to the electric pump 12. Further, the electric pump 12 can be stopped even during the operation of the internal combustion engine 1.

  In this embodiment, the electric pump 12 is stopped when it is necessary to store heat in the heat storage device 20. Thereby, the temperature of the cooling water in the water jacket 4 (hereinafter also referred to as the inside of the internal combustion engine 1) can be quickly raised. Then, when the cooling water temperature in the water jacket 4 is sufficiently increased, the electric pump 12 is operated, and the three-way valve 21 is controlled so that the cooling water flows to the heat storage device 20. Thereafter, when heat is stored in the heat storage device 20, the three-way valve 21 is controlled so that the cooling water flows to the heater core 7.

  Note that when the occupant needs to flow the cooling water to the heater core 7 by, for example, switching on the heater, the electric pump 12 may be operated to flow the cooling water to the heater core 7. Moreover, you may make it stop the electric pump 12 on the conditions which do not have a possibility that the cooling water in the water jacket 4 may boil.

  Here, FIG. 2 is a time chart showing transitions of the cooling water temperature inside the internal combustion engine 1, the portion through which the three-way valve 21 flows cooling water, and the operating state of the electric pump 12.

  When the electric pump 12 is stopped (OFF), the cooling water temperature inside the internal combustion engine 1 rises. Since the temperature has not yet risen enough to flow through the heat storage device while the cooling water is rising, the three-way valve 21 flows the cooling water to the heater core 7. When the cooling water temperature inside the internal combustion engine 1 becomes sufficiently high, the electric pump 12 is activated (ON), and at the same time, the three-way valve 21 causes the cooling water to flow through the heat storage device 20. At this time, since the cooling water staying outside the internal combustion engine 1 flows into the internal combustion engine 1, the cooling water temperature decreases. Then, the three-way valve 21 is controlled so that the cooling water having a low temperature does not flow through the heat storage device 20, whereby the cooling water flows into the heater core 7.

  Next, the flow of heat storage control in the present embodiment will be described.

  FIG. 3 is a flowchart showing a flow of heat storage control in the present embodiment. This routine is repeatedly executed every predetermined time.

  In step S101, it is determined whether a condition for storing heat in the heat storage device 20 is satisfied. That is, it is determined whether or not the coolant temperature stored in the heat storage device 20 is equal to or lower than a predetermined value, the electric pump 12 is stopped, and the coolant temperature inside the internal combustion engine 1 is equal to or higher than a predetermined value. The

  Here, the fact that the coolant temperature stored in the heat storage device 20 is equal to or lower than a predetermined value means that heat needs to be stored in the heat storage device 20. Moreover, the electric pump 12 being stopped means that the temperature of the cooling water inside the internal combustion engine 1 has been raised. Furthermore, that the cooling water temperature inside the internal combustion engine 1 is equal to or higher than a predetermined value means that the cooling water temperature inside the internal combustion engine 1 is rising enough to be stored in the heat storage device 20. Yes.

  The cooling water temperature in the heat storage device 20 can be obtained, for example, by attaching a temperature sensor in the heat storage device 20. The cooling water temperature inside the internal combustion engine 1 can be estimated from the cooling water temperature obtained from the cooling water temperature sensor 13, for example.

  If an affirmative determination is made in step S101, the process proceeds to step S102. On the other hand, if a negative determination is made, this routine is temporarily terminated.

  In step S102, heat is stored in the heat storage device 20. That is, the electric pump 12 is operated, and the three-way valve 21 is controlled to flow cooling water to the heat storage device 20.

  In this way, even before the internal combustion engine 1 is completely warmed up, that is, even if the cooling water temperature in each circulation passage has not yet risen to the temperature at which the warming-up is completed, the cooling water temperature inside the internal combustion engine 1 Therefore, heat can be quickly stored in the heat storage device 20. Thereby, even if the operation time of the internal combustion engine 1 is short, heat can be stored in the heat storage device 20. Further, the cooling water having a higher temperature can be stored in the heat storage device 20. Furthermore, it is not necessary to control the thermostat 11 electrically.

  In this embodiment, the output of the internal combustion engine 1 is limited to a predetermined value or less so that the coolant temperature does not rise excessively while the electric pump 12 is stopped. Therefore, in this embodiment, a hybrid system is provided in addition to the apparatus of the first embodiment.

  FIG. 4 is a schematic configuration diagram of a hybrid system in the present embodiment.

  The hybrid system according to this embodiment includes an internal combustion engine 1, a power split mechanism 31, an electric motor 32, a generator 33, a battery 34, an inverter 35, an axle 36, a speed reducer 37, and wheels 38.

  The power split mechanism 31 distributes the output from the internal combustion engine 1 to the generator 33 and the axle 36. The power split mechanism 31 also has a function of transmitting the output from the electric motor 32 to the axle 36. The electric motor 32 rotates at a rotational speed proportional to the axle 36 via the speed reducer 37. The electric motor 32 can assist the output of the internal combustion engine 1 as necessary during normal operation. A battery 34 is connected to the electric motor 32 and the generator 33 via an inverter 35. The generator 33 obtains power from the internal combustion engine 1 to generate power and charge the battery 34.

  In the hybrid system configured as described above, during normal traveling, the wheel 36 is driven by rotating the axle 36 by the output of the internal combustion engine 1 or the output of the electric motor 32. Further, the wheel 36 can be driven by rotating the axle 36 by combining the output of the internal combustion engine 1 and the output of the electric motor 32. On the other hand, at the time of deceleration, the electric motor 32 is operated as a generator by the rotational force of the wheel 38, whereby the kinetic energy can be converted into electric energy and collected by the battery 34. Thus, since the kinetic energy is converted into electric energy when the vehicle is decelerated, it is possible to assist the deceleration of the vehicle.

  In this embodiment, the electric motor 32 is controlled so that the output of the internal combustion engine 1 becomes a predetermined value or less while the electric pump 12 is stopped to store heat in the heat storage device 20. That is, when the required load on the internal combustion engine 1 is high and the output of the internal combustion engine 1 exceeds a predetermined value, the excess is compensated by the output of the electric motor 32.

  Next, the flow of heat storage control according to this embodiment will be described.

  FIG. 5 is a flowchart showing a flow of heat storage control according to the present embodiment. This routine is repeatedly executed every predetermined time.

  In step S201, it is determined whether a condition for storing heat in the heat storage device 20 is satisfied. That is, whether or not the coolant temperature stored in the heat storage device 20 is equal to or lower than a predetermined value, the charge amount of the battery 34 is within a predetermined value range, and the output required for the internal combustion engine 1 is equal to or lower than the predetermined value. Is determined.

Here, the fact that the coolant temperature stored in the heat storage device 20 is equal to or lower than a predetermined value means that heat needs to be stored in the heat storage device 20. Moreover, the charge amount of the battery 34 being within the predetermined value range means that a charge amount sufficient to supplement the output of the internal combustion engine 1 with the electric motor 32 is secured. Furthermore, the output required for the internal combustion engine 1 being equal to or less than a predetermined value means that an output that cannot be compensated for by the electric motor 32 is not required.

  The output required for the internal combustion engine 1 can be obtained from the output signal of the accelerator opening sensor 15.

  If an affirmative determination is made in step S201, the process proceeds to step S202. On the other hand, if a negative determination is made, the process proceeds to step S203.

  In step S202, the output of the internal combustion engine 1 is limited. That is, when the required output is higher than a predetermined value, the output of the electric motor 32 is increased. The predetermined value here is an upper limit value of the output of the internal combustion engine 1 that can suppress the boiling of the cooling water inside the internal combustion engine 1.

  In step S203, normal control of the electric pump 12 is performed. Normal control here refers to control of the electric pump 12 except when heat is stored in the heat storage device 20. Here, the electric pump 12 is operated, or the coolant flow rate is controlled in accordance with the operating state of the internal combustion engine 1.

  In step S204, it is determined whether or not the cooling water temperature inside the internal combustion engine 1 is equal to or higher than a predetermined value.

  Here, the cooling water temperature inside the internal combustion engine 1 being equal to or higher than a predetermined value means that the cooling water temperature inside the internal combustion engine 1 is rising enough to be stored in the heat storage device 20. ing.

  If an affirmative determination is made in step S204, the process proceeds to step S205. On the other hand, if a negative determination is made, the process proceeds to step S206.

  In step S205, heat is stored in the heat storage device 20. That is, the electric pump 12 is operated, and the three-way valve 21 is controlled to flow cooling water to the heat storage device 20.

  In step S206, the electric pump 12 is stopped. Thereby, the cooling water temperature inside the internal combustion engine 1 is further increased.

  In this manner, the temperature of the cooling water inside the internal combustion engine 1 can be quickly raised while limiting the output of the internal combustion engine 1, so that heat can be quickly stored in the heat storage device 20. Even if, for example, rapid acceleration is performed when the electric pump 12 is stopped, the output of the internal combustion engine 1 is limited, so that the coolant temperature is prevented from excessively rising. Further, local boiling of the cooling water inside the internal combustion engine 1 is suppressed. As a result, the durability and reliability of the internal combustion engine 1 can be improved.

  In this embodiment, when the output of the internal combustion engine 1 is small, the output of the internal combustion engine 1 is increased by increasing the load of the internal combustion engine 1, thereby increasing the temperature of the cooling water inside the internal combustion engine 1 early. Plan. Therefore, the present embodiment includes the hybrid system described in the second embodiment.

  Here, when the generator 33 generates power when the output of the internal combustion engine 1 is small, the load on the internal combustion engine 1 increases and the output of the internal combustion engine 1 increases. The electric power obtained at this time can be charged to the battery 34.

  Next, the flow of heat storage control according to this embodiment will be described.

  FIG. 6 is a flowchart showing a flow of heat storage control according to the present embodiment. This routine is repeatedly executed every predetermined time. In addition, about the step in which the same process as the said flowchart is made, the same number is attached and description is abbreviate | omitted.

  In step S301, it is determined whether the required output of the internal combustion engine 1 is equal to or less than a predetermined value. Here, it is determined whether or not the output of the internal combustion engine 1 necessary for increasing the coolant temperature inside the internal combustion engine 1 at an early stage cannot be obtained.

  If an affirmative determination is made in step S301, the process proceeds to step S302. On the other hand, if a negative determination is made, the process proceeds to step S204.

  In step S302, the output of the internal combustion engine 1 is increased. The amount of power generated by the generator 33 is adjusted so that the output of the internal combustion engine 1 becomes a predetermined value.

  In this way, the temperature of the cooling water inside the internal combustion engine 1 can be quickly raised while increasing the output of the internal combustion engine 1, so that heat can be quickly stored in the heat storage device 20.

It is a figure which shows schematic structure of the thermal storage apparatus of the internal combustion engine which concerns on an Example. It is the time chart which showed transition of the cooling water temperature inside an internal-combustion engine, the part which a three-way valve flows cooling water, and the operating state of an electric pump. It is the flowchart which showed the flow of the heat storage control in Example 2. FIG. It is a schematic block diagram of the hybrid system in an Example. It is the flowchart which showed the flow of the heat storage control by Example 2. FIG. 6 is a flowchart showing a flow of heat storage control according to a third embodiment.

Explanation of symbols

1 Internal combustion engine 2 Cylinder head 3 Cylinder block 4 Water jacket 5 Radiator 6 First circulation passage 7 Heater core 8 Second circulation passage 9 Bypass passage 10 Third circulation passage 11 Thermostat 12 Electric pump 13 Cooling water temperature sensor 14 ECU
15 Accelerator opening sensor 16 Crank position sensor 20 Heat storage device 21 Three-way valve 31 Power split mechanism 32 Electric motor 33 Generator 34 Battery 35 Inverter 36 Axle 37 Reducer 38 Wheel

Claims (3)

A pump that circulates the cooling water of the internal combustion engine and can change the flow rate of the cooling water flowing through the internal combustion engine ;
A heat storage device for storing heat by storing cooling water of the internal combustion engine;
The temperature of the cooling water is raised by stopping the flow of the cooling water inside the internal combustion engine by stopping the pump while operating the internal combustion engine before storing heat in the heat storage device. Heat storage control means for operating and introducing cooling water to the heat storage device;
A heat storage device for an internal combustion engine, comprising:   The hybrid system having a motor is further provided, and the motor is operated so that the output of the internal combustion engine becomes equal to or less than a first predetermined value when the pump is stopped by the heat storage control means. A heat storage device for an internal combustion engine as described.   The hybrid system having a motor is further provided, and the motor is operated so that an output of the internal combustion engine becomes a second predetermined value or more when the pump is stopped by the heat storage control means. 2. A heat storage device for an internal combustion engine according to 2.

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