JP2002242637A - Internal combustion engine with heat insulated device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine equipped with a heat insulated device capable of suppressing the temperature of each piston during the engine at a standstill and also drop of the working oil temperature in a valve characteristic changing mechanism and thereby preventing deterioraion of the exhaust emission immediately after the engine is started. SOLUTION: The internal combustion engine is equipped with pistons 3, a lubricating oil supplying means 18 to supply lubricating oil to the pistons, a lubricating oil discharging means 16 to discharge the lubricating oil to the supplying means 18, and the heat insulated device 10 to suppress the variation of the temperature of the lubricating oil, whereby the lubricating oil kept warm in each piston 3 is supplied even before the engine is started.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Generally, when an air-fuel mixture supplied to an internal combustion engine burns and a flame propagates to the surroundings, the temperature of the flame decreases near the piston, so that the flame is extinguished. This layer is called an anti-extinguishing layer, and unburned hydrocarbon (HC) remains in this portion. In particular, when the temperature of the piston is low immediately after the start of the internal combustion engine, a large amount of unburned hydrocarbons (HC) is generated due to the thick flame-extinguishing layer, and the temperature of the exhaust purification catalyst has not reached the activation temperature. In addition, there is a possibility that this hydrocarbon (HC) is released into the atmosphere without being purified.

In order to solve such a problem, see, for example,
In Japanese Patent Application Publication No. 00-54872, a solution is provided by providing a valve characteristic changing mechanism capable of changing the valve opening timing of the exhaust valve and by providing exhaust interference means for retaining exhaust gas discharged from the combustion chamber. In the internal combustion engine configured as described above, the opening timing of the exhaust valve is advanced when the activation of the exhaust purification catalyst is required. Then, the combustion gas containing high amounts of unburned hydrocarbons (HC) at a high temperature and high pressure during the expansion stroke is discharged vigorously. Then, the stagnation in the exhaust interference means promotes mixing with excess oxygen present in the exhaust gas and in the exhaust interference means. Then, the unburned hydrocarbons (HC) in the exhaust react with the excess oxygen and burn,
The temperature of the exhaust rises early. In this way, early activation of the catalyst is realized by the exhaust gas whose temperature has risen.

[0004]

However, even if it is possible to activate the exhaust purification catalyst at an early stage, it takes a certain time to activate it. Therefore, it is important to suppress the emission of unburned hydrocarbons (HC) immediately after the start of the internal combustion engine. In particular, in a direct fuel injection type internal combustion engine that directly injects fuel into a cylinder, the fuel injected into the cylinder adheres to a large amount of the piston, so that when the temperature of the piston is low, the attached fuel evaporates slowly. And the emission of unburned hydrocarbons (HC) increases, so it is more important to suppress the emission of unburned hydrocarbons (HC).

On the other hand, immediately after the start of the internal combustion engine, the operating oil used for operating the valve characteristic changing mechanism has a high viscosity due to low temperature, and the valve timing changing mechanism may not operate.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a technique for suppressing a decrease in the temperature of a piston and the temperature of hydraulic oil of a valve characteristic changing mechanism when an internal combustion engine is stopped. Accordingly, it is an object of the present invention to prevent deterioration of exhaust emission immediately after starting the internal combustion engine.

[0007]

Means for Solving the Problems To achieve the above object, an internal combustion engine provided with a heat storage device of the present invention employs the following means.

That is, a first invention according to the present application is a piston which reciprocates under the pressure of combustion gas, lubricating oil supply means for supplying lubricating oil to the piston, and lubricating oil supplying means for lubricating oil supplying means. And a heat storage device for storing heat, wherein the heat stored in the heat storage device is supplied to the lubricating oil, and the lubricating oil is supplied to the piston before the engine is started. And

In the internal combustion engine provided with the heat storage device configured as described above, heat generated during operation of the internal combustion engine is retained by the heat storage device even after the operation of the internal combustion engine is stopped.
This heat storage device can supply the stored heat to the lubricating oil, and can warm the lubricating oil even when the engine is stopped.

This lubricating oil is discharged to the lubricating oil supply means by the lubricating oil discharge means before the start of the engine. The lubricating oil supply means supplies lubricating oil to the piston, and the piston is heated by the heat of the supplied lubricating oil.

In this way, the piston can be warmed even when the engine is stopped.

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

That is, a second invention according to the present application is a valve characteristic changing mechanism which is operated by operating hydraulic pressure and changes opening / closing characteristics of an intake valve or an exhaust valve in accordance with an engine operating state. A hydraulic oil discharge means for discharging hydraulic oil to the mechanism; and a heat storage device for storing heat, wherein the heat stored in the heat storage device is supplied to the hydraulic oil, and the hydraulic oil is supplied to the valve characteristic changing mechanism when the engine is started. Is supplied.

In the internal combustion engine provided with the heat storage device configured as described above, heat generated during operation of the internal combustion engine is retained by the heat storage device even after the operation of the internal combustion engine is stopped.
This heat storage device can supply the stored heat to the hydraulic oil of the valve characteristic changing mechanism, and can warm the hydraulic oil even when the engine is started.

This hydraulic oil is discharged to the hydraulic oil supply means by the hydraulic oil discharge means immediately after the start of the engine. The hydraulic oil supply means supplies the hydraulic oil to the valve characteristic changing mechanism, and the valve characteristic changing mechanism can be operated immediately after starting the engine by the supplied high-temperature, low-viscosity hydraulic oil.

According to the present invention, hydraulic oil can be supplied to the valve characteristic changing mechanism before the engine is started.

With this configuration, the valve characteristics can be changed by a high-temperature, low-viscosity hydraulic oil before the engine is started.

In the present invention, at the time of starting the engine, the opening timing of at least one of the intake valve and the exhaust valve can be advanced.

For example, if the characteristics of the intake valve are changed and advanced, the intake valve can be closed when the piston is at the bottom dead center at the end of the intake process. Thus, the outflow of the intake air from the intake valve can be prevented. By doing so, the temperature rise during the compression step can be increased, and the vaporization of the fuel is promoted, so that the engine can be easily started.

Further, for example, when the characteristic of the exhaust valve is changed and the angle is advanced, the exhaust valve is opened during the expansion stroke, so that high-temperature combustion gas is exhausted vigorously. The temperature of the exhaust purification catalyst can be raised early by the combustion gas.

The heat storage device according to the present invention may have a structure in which lubricating oil or hydraulic oil is taken directly into the inside and heat is stored therein, or heat may be stored in another heat medium, and this heat medium may be stored. May transfer heat to lubricating oil or hydraulic oil via a heat exchanger or the like.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of a heat storage device for an internal combustion engine according to the present invention will be described below with reference to the drawings. Here, a case where the heat storage device for an internal combustion engine according to the present invention is applied to a direct injection gasoline engine for driving a vehicle will be described as an example.

FIG. 1 is a diagram schematically showing an engine 1 to which a heat storage device 10 for an internal combustion engine according to the present invention is applied, a cooling water passage for circulating cooling water and a lubricating oil passage for circulating lubricating oil. .

The engine 1 shown in FIG. 1 is a water-cooled four-cycle direct injection gasoline engine having four cylinders 2.

The engine 1 has a fuel injection valve 5 for directly injecting fuel into the combustion chamber of each cylinder 2.

A piston 3 is inserted into the cylinder 2. The piston 3 is connected to a connecting rod 4, and is connected to a crankshaft (not shown) via the connecting rod 4.

The cylinder head 1a and the cylinder block 1b are provided with a water jacket 23 as a passage for circulating cooling water. At the outlet of the water jacket 23, a water pump 6 for sucking cooling water from inside the engine 1 and discharging the cooling water to the outside of the engine 1 is provided. The water pump 6 is a pump that operates using the rotational torque of the output shaft of the engine 1 as a drive source. That is, the water pump 6 operates only when the engine 1 is operating.

The water pump 6 is connected to a water hose 7 for circulating cooling water outside the engine 1, and the water hose 7 is connected to a heater core 13 which is a heat exchanger. A water hose 7 for returning the cooling water discharged from the heater core 13 to the engine 1 is connected to an outlet of the heater core 13, and the water hose 7 is connected to the cylinder head 1a. On the water hose from the heater core 13 to the cylinder head 1a, a shutoff valve 14 for shutting off the flow of cooling water is provided. This shutoff valve is opened and closed by an electric signal from the ECU 22.

Further, the heater core 1 is
In the middle of the water hose 7 up to 3, a thermostat 8 that opens and closes depending on the temperature of the cooling water is installed. A water hose 7 is connected to an outlet of the thermostat 8, and the water hose 7 is connected to a radiator 9 which is a heat exchanger. The thermostat 8 opens when the cooling water reaches a predetermined temperature or higher, and connects a water hose from the water pump 6 to the radiator 9.

At the outlet of the radiator 9, the radiator 9
A water hose 7 for returning cooling water flowing out of the heater core to the engine 1 is connected to the water hose 7 for returning cooling water flowing out of the heater core 13 to the engine 1.

The water hose 7 from the water pump 6 to the thermostat 8 branches bifurcated on the way.
One is connected to the thermostat 8 and the other is connected to the heat storage device 10. An electric water pump 12 is installed on the water hose 7 where the water hose 7 branches into two parts and reaches the heat storage device 10. On the other hand, the heat storage device 10
A water hose 7 for returning cooling water discharged from the heat storage device 10 to the engine 1 is connected to the outlet, and the water hose 7 is connected to a radiator 9 and a shutoff valve 14.
Is connected to a water hose 7 extending from the cylinder head 1a to the cylinder head 1a. A heat exchanger 15 is provided on the water hose 7 from the heat storage device 10 to the cylinder head 1a. In addition, at the inlet and outlet of the heat storage device 10,
A one-way valve 11 for flowing the cooling water only in the direction of the arrow in FIG. 1 is provided.

In the cooling system of the engine 1 configured as described above, when the rotation torque of a crankshaft (not shown) is transmitted to the input shaft of the water pump 6 while the engine 1 is operating, the water pump 6 The cooling water is discharged at a pressure corresponding to the rotational torque transmitted from the crankshaft to the input shaft of the water pump 6.

A part of the cooling water discharged from the water pump 6 passes through the thermostat 8 and passes through the heater core 1.
Reach 3 The heater core 13 exchanges heat with air in the vehicle interior, and the air heated by the movement of the heat is circulated in the vehicle interior by a blower (not shown) to raise the ambient temperature of the vehicle interior.

The shut-off valve 14 is opened while the engine 1 is operating, and is closed while the engine 1 is stopped. During operation of the engine 1, the cooling water flowing out of the heater core 13 passes through the shutoff valve 14 and reaches the cylinder head 1 a via the water hose 7. Engine 1 from cylinder head 1a
The cooling water that has flowed into the inside flows through the water jacket 23. In the water jacket 23, heat is transferred between the cylinder head 1a and the cylinder block 1b and the cooling water. Part of the heat generated by the combustion in the cylinder 2 is transmitted to the wall surface of the cylinder 2 and further transmitted inside the cylinder head 1a and the cylinder block 1b, so that the temperature of the entire cylinder head 1a and the cylinder block 1b rises. Cylinder head 1a and cylinder block 1
Part of the heat transmitted to b is transmitted to the cooling water inside the water jacket 23, and raises the temperature of the cooling water. Further, the temperatures of the cylinder head 1a and the cylinder block 1b that have lost the heat decrease.

The cooling water whose temperature has been increased in this way is discharged from the cylinder block 1b by the water pump 6 and repeatedly circulated.

When the temperature of the cooling water flowing through the thermostat 8 reaches a predetermined temperature, the thermostat 8 automatically opens due to the thermal expansion of the wax. When the thermostat 8 opens, the cooling water flows into the radiator 9 via the water hose 7. In the radiator 9, heat is transferred between the outside air and the cooling water. Part of the heat of the cooling water having a higher temperature is transmitted to the wall surface of the radiator 9 and further transmitted inside the radiator 9 to increase the temperature of the entire radiator 9. Part of the heat transmitted to the radiator 9 is transmitted to the outside air and raises the temperature of the outside air. In addition, the temperature of the cooling water that has lost the heat decreases accordingly. After the temperature drops, the cooling water flowing out of the radiator 9 flows into the cylinder head 1a via the water hose 7.

On the other hand, part of the cooling water discharged from the water pump 6 is transferred to the heat storage device 10 via the water hose 7.
Flows into the interior. In the heat storage device 10, a vacuum heat insulating space is provided between the outer container 10a and the inner container 10b, and the cooling water flowing from the cooling water injection pipe 10c flows out of the cooling water discharge pipe 10d. The cooling water flowing into the heat storage device 10 is kept insulated from the outside and kept warm. The cooling water flowing out of the heat storage device 10 flows into the heat exchanger 15 via the water hose 7. The cooling water that has passed through the heat exchanger 15 flows into the cylinder head 1a via the water hose 7. Also, the one-way valve 11 prevents the cooling water from flowing back to the heat storage device 10.

As described above, the cooling water whose temperature has increased during the operation of the engine 1 constantly flows through the heat storage device 10.

Next, the engine 1 is provided with an oil pump 24 for circulating lubricating oil.

The oil pump 24 is a pump that operates using the rotational torque of the output shaft of the engine 1 as a drive source. That is, the oil pump 24 operates only when the engine 1 is operating.

An oil strainer 26 is connected to an inlet of the oil pump 24 via an oil tube 25.

At the outlet of the oil pump 24, a cylinder block 1b for circulating lubricating oil inside the engine 1 is provided.
The oil gallery 17 is opened. The oil gallery 17 has an oil jet 18 for cooling the piston 3 whose temperature has increased during operation of the engine 1.
Is provided.

An oil control valve 21 is connected to the oil gallery 17 via an oil tube 25, and the oil control valve 21 is further connected to a valve characteristic changing mechanism 20 via the oil tube 25. .

The outlet of the oil control valve 21 is connected to the cylinder block 1 via an oil tube 25.
b.

Further, the oil gallery 17 is connected to the heat exchanger 15 via an oil tube 25, and the heat exchanger 15 is connected to the electric oil pump 16 via the oil tube 25. An oil tube 25 is connected to the oil pan 1c.
Is connected to the oil supply valve 19. The oil supply valve 19 is opened and closed by a signal from the ECU 22. The oil supply valve 19 is connected to the heat exchanger 15 via an oil tube 25.

In the lubrication system of the engine 1 configured as described above, when the rotation torque of the crankshaft (not shown) is transmitted to the input shaft of the oil pump 24 while the engine 1 is operating, it is stored in the oil pan 1c. The removed lubricating oil is sucked up by an oil pump 24 via an oil tube 25 after impurities are removed by an oil strainer 26. Then, the oil pump 24 discharges the lubricating oil at a pressure corresponding to the rotation torque transmitted from a crankshaft (not shown) to the input shaft of the oil pump 24.

A part of the lubricating oil discharged from the oil pump 24 reaches the oil jet 18 via the oil gallery 17. The oil jet 18 is formed of a metal pipe, and the lubricating oil that has passed through the inside of the oil jet 18 is injected from the end of the oil jet 18 toward the back surface of the piston 3 by the pressure from the oil pump 24. Then, heat is transferred between the lubricating oil attached to the back surface of the piston 3 and the piston 3, and the temperature of the lubricating oil increases. On the other hand, the temperature of the piston 3 decreases due to this heat transfer. The lubricating oil whose temperature has risen due to the transfer of heat to and from the piston 3 flows down to the oil pan 1c.

Thus, the cooling of the piston 3 is performed.

A part of the lubricating oil discharged from the oil pump 24 reaches the oil control valve 21 via the oil gallery 17 and the oil tube 25.

FIG. 2B is a schematic view showing the structure of the oil control valve 21.

The oil control valve 21 has an inlet 54 through which part of the lubricating oil discharged from the oil pump 24 flows in through the oil tube 25 and outlets 53, 55 for discharging the lubricating oil to the cylinder block 1b. have. Further, it has inflow / outflow ports 51 and 52 connected to the valve characteristic changing mechanism 20 via the oil tube 25. Inside the oil control valve 21, a spool valve 50 and a coil 56 for moving the spool valve 50 according to a signal from the ECU 22 are provided.

FIG. 2A is a schematic diagram showing the structure of the valve characteristic changing mechanism 20.

The valve characteristic changing mechanism 20 includes a sprocket 63 driven by a timing belt (not shown) and a vane 64 connected to a cam shaft (not shown).

The space between the sprocket 63 and the vane 64 has an advance chamber 61 and a retard chamber 62 into and out of which lubricating oil flows. The advance chamber 61 has an inflow / outflow port 51,
The retard chamber 62 is provided with the inflow / outflow port 52 and the oil tube 2 respectively.
5 are connected.

The center axis of the sprocket 63 and the center axis of the vane 64 are on the same axis, and the vane 64 rotates about this axis. This rotation can be performed until the space of the advance chamber 61 or the retard chamber 62 is exhausted.

With the oil control valve 21 and the valve characteristic changing mechanism 20 configured as described above, when it is necessary to shift the valve timing to the advance side, the EC
U22 sends a signal to the coil 56 to move the spool valve 50 to the position shown in FIG. Then, the inlet 54
And the inflow / outflow port 51 are in communication with each other, and the outflow port 55 and the inflow / outflow port 52 are in communication. And the oil pump 2
A part of the lubricating oil discharged from 4 flows into the oil control valve 21 from the inlet 54, passes through the oil control valve 21, and flows out from the inlet 51.

The lubricating oil flowing out of the oil control valve 21 flows into the advance chamber 61 through the oil tube 25. The lubricating oil flowing into the advance chamber 61 increases the pressure in the advance chamber 61 by the pressure from the oil pump 24. The vane 64 receiving this pressure rotates in the direction of the arrow in FIG. The lubricating oil flows out of the retard chamber 62. The lubricating oil that has flowed out reaches the inflow / outflow port 52 via the oil tube 25. The lubricating oil that has reached the inflow port 52 flows into the oil control valve 21, passes through the oil control valve 21, and flows out of the outflow port 55.

Thus, the lubricating oil is supplied to the advance chamber 61 to rotate the vane 64, so that the phase of the intake camshaft (not shown) can be continuously changed to the advance side.

On the other hand, when it is necessary to shift the valve timing to the retard side, the ECU 22 sends a signal to the coil 56 to move the spool valve 50 to the position shown in FIG. Then, the inflow port 54 and the inflow / outflow port 52 are in communication, and the outflow port 53 and the inflow / outflow port 51 are in communication. Part of the lubricating oil discharged from the oil pump 24 is
The oil flows into the oil control valve 21 from the inlet 54, passes through the oil control valve 21, and flows out from the inlet 52.

The lubricating oil flowing out of the oil control valve 21 flows into the retard chamber 62 through the oil tube 25. The lubricating oil flowing into the retard chamber 62 increases the pressure in the retard chamber 62 by the pressure from the oil pump 24. Under this pressure, the vane 64 moves as shown in FIG.
It rotates in the arrow direction of (a). The lubricating oil flows out of the advance chamber 61. The lubricating oil that has flowed out reaches the inflow / outflow port 51 via the oil tube 25. Inlet / outlet 5
1 reaches the oil control valve 21
And passes through the inside of the oil control valve 21 and flows out of the outlet 53.

Thus, the lubricating oil is supplied to the retard chamber 62 to rotate the vane 64, so that the phase of the intake camshaft (not shown) can be continuously changed to the retard side.

The lubricating oil flowing out of the outlet 53 or the outlet 55 is discharged to the cylinder block 1b via the oil tube 25. The lubricating oil discharged to the cylinder block 1b flows down to the oil pan 1c. in this way,
The lubricating oil is also used as a hydraulic oil for the valve characteristic changing mechanism 20.

The engine 1 configured as described above is provided with an electronic control unit (ECU) 22 for controlling the engine 1. The ECU 22 controls the operating state of the engine 1 according to the operating conditions of the engine 1 and a request from the driver,
Further, this unit is for raising the temperature of the piston 3 and the lubricating oil while the operation of the engine 1 is stopped.

The ECU 22 includes a fuel injection valve 5, an electric water pump 12, a shutoff valve 14, an electric oil pump 16,
The oil supply valve 19, the oil control valve 21 and the like are connected via electric wiring, and the above-described components are connected to the ECU 22.
Can be controlled.

Here, as shown in FIG. 5, the ECU 22 is connected to a C
A PU 351, a ROM 352, a RAM 353, a backup RAM 354, an input port 356, and an output port 357.
And an A / D converter (A / D) 355 connected to.

The output port 357 is connected to the fuel injection valve 5,
The electric water pump 12, the shut-off valve 14, the electric oil pump 16, the oil supply valve 19, the oil control valve 21 and the like are connected via electric wiring and control signals output from the CPU 351 are transmitted to the fuel injection valve 5, the electric Water pump 12, shut-off valve 14, electric oil pump 1
6. Oil supply valve 19, oil control valve 21
Send to

The ROM 352 includes a fuel injection control routine for controlling the fuel injection valve 5, an electric water pump control routine for controlling the electric water pump 12, a shutoff valve control routine for controlling the shutoff valve 14,
Electric oil pump control routine for controlling the electric oil pump 16, oil supply valve control routine for controlling the oil supply valve 19, oil control valve 2
An application program such as an oil control valve control routine for controlling the first control valve is stored.

The ROM 352 stores various control maps in addition to the application programs described above. The control map includes, for example, a fuel injection amount control map indicating a relationship between an operating state of the engine 1 and a basic fuel injection amount (basic fuel injection time), and a fuel indicating a relationship between an operating state of the engine 1 and a basic fuel injection timing. An injection timing control map and the like.

The RAM 353 stores an output signal from each sensor, a calculation result of the CPU 351 and the like. The calculation result is, for example, an engine speed calculated based on a time interval at which the crank position sensor 27 outputs a pulse signal. These data are rewritten to the latest data every time the crank position sensor 27 outputs a pulse signal.

The backup RAM 354 is a nonvolatile memory capable of storing data even after the operation of the engine 1 is stopped.

Next, the piston 3 and the valve characteristic changing mechanism 2 before the operation of the engine 1 according to the present invention is started.
A method of keeping the lubricating oil, which is the hydraulic oil of No. 0, will be described.

During operation of the engine 1, the cooling water is constantly circulated through the heat storage device 10, so that the cooling water heated by the engine 1 is stored inside the heat storage device 10. Then, even when the engine 1 is stopped, the cooling water stored in the heat storage device 10 is prevented from lowering in temperature due to the heat retention effect of the heat storage device 10.

By circulating the cooling water and the lubricating oil before the operation of the engine 1 is started, the temperature of the lubricating oil, which is the operating oil of the piston 3 and the valve characteristic changing mechanism 20, can be increased. As the condition for starting the circulation of the cooling water and the lubricating oil, the opening and closing of the door of the driver's seat that the driver inevitably performs before starting the engine 1 can be exemplified.

The CPU 351 accesses the RAM 353, and when the pulse signal of the crank position sensor 27 is not transmitted and the opening / closing of the driver's seat door is detected by a door opening / closing sensor (not shown), the electric water pump 12 Then, the electric oil pump 16 is operated, the shutoff valve 14 is closed, the oil supply valve 19 is opened, and the oil control valve 21 is set to the advanced side.

Here, when the engine 1 stops, the water pump 6 also stops, so that the electric water pump 12 is operated to circulate the cooling water.

The electric water pump 12 is operated by a signal from the ECU 22 to discharge cooling water at a predetermined pressure. The cooling water discharged from the electric water pump 12 passes through the water hose 7 and flows into the heat storage device 10 via the cooling water injection pipe 10c. The cooling water stored inside the heat storage device 10 flows out of the heat storage device 10 via the cooling water discharge pipe 10d. At this time, the heat storage device 10
Is flowing into the heat storage device 10 during the operation of the engine 1 and is a high-temperature cooling water kept warm by the heat storage device 10. The cooling water flowing out of the heat storage device 10 flows into the heat exchanger 15 via the water hose 7. In the heat exchanger 15, heat is transferred to and from the lubricating oil.

Then, the cooling water having passed through the heat exchanger 15 flows into the cylinder head 1a via the water hose 7. The cooling water flowing into the engine 1 from the cylinder head 1a flows through the water jacket 23.
In the water jacket 23, heat is transferred between the cylinder head 1a and the cylinder block 1b and the cooling water. Part of the heat of the cooling water is transmitted inside the cylinder head 1a and the cylinder block 1b, and the temperature of the entire cylinder head 1a and the cylinder block 1b rises. In addition, the temperature of the cooling water that has lost the heat decreases accordingly.

The cooling water whose temperature has been lowered in this way flows out of the cylinder block 1b through the stopped water pump 6, and flows out.
Reach 2.

Here, since the shutoff valve 14 is closed, cooling water is not circulated through the heater core 13, so that heat is transferred between the heater core 13 and the vehicle interior air. Unnecessary lowering of the temperature of the cooling water can be prevented.

When the temperature of the cooling water falls below a predetermined temperature, the thermostat 8 closes, so that the cooling water is supplied to the radiator 9.
And the temperature does not decrease in the radiator 9.

As described above, even when the engine 1 is stopped, the high-temperature cooling water is supplied to the heat storage device 10 and the heat exchanger 15.
Can be circulated.

Next, when the engine 1 stops, the oil pump 24 also stops, so that the electric oil pump 16 is operated to circulate the lubricating oil.

The electric oil pump 16 includes an oil pan 1c
The lubricating oil stored in the tank is sucked up through the oil tube 25. Then, the lubricating oil that has passed through the oil supply valve 19 opened by the ECU 22 flows into the heat exchanger 15. In the heat exchanger 15, heat is transferred between the cooling water and the lubricating oil, and the lubricating oil is heated by the heat from the cooling water.

The lubricating oil whose temperature has increased reaches the electric oil pump 16, and the electric oil pump 16 discharges the lubricating oil at a predetermined pressure.

A part of the lubricating oil discharged from the oil pump 24 is supplied to the oil tube 25 and the oil gallery 1.
It reaches the oil jet 18 via 7. The oil jet 18 is made of a metal pipe, and the oil jet 1
The lubricating oil that has passed through the inside of the oil jet 8 is pressed from the end of the oil jet 18 by the pressure from the oil pump 24.
Is sprayed toward the back surface of. The lubricating oil attached to the back surface of the piston 3 moves heat between the piston 3 and the piston 3 to increase the temperature of the piston 3. On the other hand, the temperature of the lubricating oil decreases due to this heat transfer. The lubricating oil whose temperature has been lowered by transferring heat to and from the piston 3 flows down to the oil pan 1c.

Thus, the temperature of the piston 3 is raised.

A part of the lubricating oil discharged from the electric oil pump 16 reaches the oil control valve 21 via the oil tube 25. The lubricating oil distributed by the oil control valve 21 circulates through the valve characteristic changing mechanism 20 via the oil tube 25, and then returns to the oil control valve 21. Then, the lubricating oil flowing out of the oil control valve 21 is discharged to the cylinder block 1b via the oil tube 25. Thereafter, the lubricating oil flows down to the oil pan 1c.

As described above, the lubricating oil circulates through the oil control valve 21 and the valve characteristic changing mechanism 20 as the operating oil of the valve characteristic changing mechanism 20 even when the engine 1 is stopped. In addition, since the lubricating oil is heated to a lower temperature by transferring heat between the lubricating oil and the cooling water, the oil control valve 21 and the valve characteristic changing mechanism 20 are operated while the engine 1 is stopped. It becomes possible.

When the engine 1 is started with the lubricating oil, which is the operating oil of the piston 3 and the valve characteristic changing mechanism 20, kept warm, the fuel is injected from the fuel injection valve 5 into the cylinder 2. Even if fuel adheres to the piston, it can be vaporized early.

Further, since the valve characteristic changing mechanism 20 can be controlled before the engine 1 is started, the engine 1 can be controlled.
The characteristics of the valve (not shown) can be changed according to the operating state of the engine 1 from the start of the operation. Therefore, in the present embodiment, when the piston is at the bottom dead center at the end of the intake stroke, the engine 1 is started by advancing the valve timing on the intake side so that the intake valve is closed. And

In this way, it is possible to prevent the fresh air from flowing out of the intake valve in the compression step, so that the temperature rise during the compression step becomes large, and the vaporization of fuel is promoted, and the start of the engine 1 becomes easy. .

After the engine 1 is started, the valve timing on the intake side is retarded so as to eliminate the overlap between the intake side and the exhaust side, thereby preventing the air from returning to the intake side.
Combustion in the cylinder 2 is stabilized.

In this embodiment, the engine 1
Before the start of the operation, the electric water pump 12 and the electric oil pump 16 are operated, the shutoff valve 14 is closed, the oil supply valve 19 is opened, and the oil control valve 21 is opened.
Is set to the advanced side, but these controls can be performed at the time of starting the engine 1 or even after the starting.

Although the valve characteristic changing mechanism according to the present embodiment has a mechanism for rotating the camshaft by using the pressure of the hydraulic oil, the present invention relates to another valve operating mechanism using the hydraulic oil. A plurality of mechanisms, for example, a plurality of cams having different operation angles are set, and this also effectively acts on a valve operating mechanism that switches the cam to be used based on the operating state by hydraulic pressure.

[0095]

According to the heat storage device for an internal combustion engine according to the present invention,
While the operation of the internal combustion engine is stopped, the lubricating oil and the hydraulic oil of the valve characteristic changing mechanism can be circulated while raising the temperature. Therefore, the valve characteristic changing mechanism can be operated before the engine operation starts. Further, the operation of the internal combustion engine can be started with the temperature of the piston being high.

Thus, deterioration of exhaust emission can be suppressed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine including a heat storage device according to the present invention, a cooling system thereof, and a lubricating oil path.

FIG. 2 is a diagram showing a schematic configuration of an oil control valve and a valve characteristic changing mechanism.

FIG. 3 is a diagram showing the operation of an oil control valve and a valve characteristic changing mechanism during advancement.

FIG. 4 is a diagram showing the operation of an oil control valve and a valve characteristic changing mechanism at the time of retarding.

FIG. 5 is a block diagram showing an internal configuration of an ECU.

[Explanation of symbols]

 1 ... Engine 1a ... Cylinder head 1b ... Cylinder block 1c ... Oil pan 2 ... Cylinder 3 ... Piston 4 ... Connecting rod 5 ... Fuel injection Valve 6 Water pump 7 Water hose 8 Thermostat 9 Radiator 10 Heat storage device 10a Outer container 10b Inner container 10c Cooling water injection pipe 10d ··· Cooling water discharge pipe 11 ··· One-way valve 12 ··· Electric water pump 13 ··· Heater core 14 ··· Shut-off valve 15 ··· Heat exchanger 16 ··· Electric oil pump 17 ··· Oil gallery 18 Oil jet 19 Oil supply valve 20 Valve characteristic changing mechanism 21 Oil control valve 22 ECU 3 Water Jacket 24 Oil Pump 25 Oil Tube 26 Oil Strainer 27 Crank Position Sensor 50 Spool Valve 51 Inlet Outlet 52 Inlet Outlet 53 ... Outlet 54 ... Inlet 55 ... Outlet 56 ... Coil 61 ... Advance chamber 62 ... Delay chamber 63 ... Sprocket 64 ... Vane

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 13/02 F02D 13/02 H 41/06 320 41/06 320 43/00 301 43/00 301Z F-term (Ref.) AA06 AA11 AB02 DA01 DA02 DA08 DF04 DG05 EA03 EC03 EC09 FA11 FA18 FA31 GA01 GA10 GB10 HA13X HE04Z HE08Z HE09Z HF00Z 3G301 HA01 HA04 HA19 JA26 KA01 KA28 LA07 LC08 NA07 NB11 NC02 ND04 PE04Z PE08Z PE10ZPF00

Claims (4)

[Claims] A piston reciprocating under the pressure of the combustion gas; a lubricating oil supply unit for supplying lubricating oil to the piston; a lubricating oil discharging unit for discharging lubricating oil to the lubricating oil supplying unit; An internal combustion engine equipped with a heat storage device, comprising: supplying heat stored in the heat storage device to lubricating oil; and supplying the lubricating oil to a piston before starting the engine. 2. A valve characteristic changing mechanism which is operated by an operating oil pressure and changes opening / closing characteristics of an intake valve or an exhaust valve according to an engine operating state; and a hydraulic oil discharge for discharging hydraulic oil to the valve characteristic changing mechanism. Means, and a heat storage device for storing heat, wherein the heat stored in the heat storage device is supplied to hydraulic oil, and the hydraulic oil is supplied to a valve characteristic changing mechanism when the engine is started. Internal combustion engine equipped with. 3. An internal combustion engine equipped with a heat storage device according to claim 2, wherein hydraulic oil is supplied to the valve characteristic changing mechanism before the engine is started. 4. An internal combustion engine provided with a heat storage device according to claim 2, wherein at least one of an intake valve and an exhaust valve is advanced when the engine is started.