JP2016118119A - Valve device of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve device of an engine which can quickly raise a temperature in a combustion chamber by suppressing heat dissipation via an umbrella part and a valve seat of a hollow valve at a cold start of the engine.SOLUTION: A valve device of an engine comprises: a hollow valve which has a shaft part reciprocally supported by a stem guide arranged in a cylinder head of the engine, and an umbrella part arranged at a lower end of the shaft part, and contacting with a valve seat at valve-closing, and having a hollow part formed toward the umbrella part from the shaft part, and which is sealed in the hollow part, with a magnetic body which can circulate in the hollow part; an electromagnet arranged at a periphery of the stem guide; and a control part which controls electricity-carrying to the electromagnet.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an engine valve device.

  2. Description of the Related Art Conventionally, a hollow valve for an engine in which a hollow portion is formed from an umbrella portion to a shaft portion and a refrigerant is sealed in the hollow portion is known (see, for example, Patent Document 1).

  In the hollow valve described in Patent Document 1, a temperature-sensitive on-off valve device (hereinafter referred to as “temperature-sensitive valve”) is provided in the hollow portion formed in the shaft portion. The shaft portion is supported by a stem guide provided in the cylinder head so as to be movable up and down. The temperature sensitive valve is provided below the stem guide. The hollow portion is partitioned into an upper chamber and a lower chamber via a temperature sensitive valve.

  The temperature sensitive valve has a coil spring made of a shape memory alloy and a valve body attached to the tip of the coil spring. When the temperature in the hollow part is lower than the opening temperature of the temperature sensitive valve, the temperature-sensitive valve closes the communication hole between the upper chamber and the lower chamber in the hollow part (valve closed state) by extending the coil spring. When the temperature is equal to or higher than the opening operation temperature of the temperature sensitive valve, the coil spring contracts to open the communication hole (valve open state).

  The refrigerant in Patent Document 1 is a low melting point alloy such as Na-K alloy.

  According to the hollow valve described in Patent Literature 1, when the temperature in the hollow portion is lower than the opening operation temperature of the temperature sensitive valve and lower than the melting point of the refrigerant, the temperature sensitive valve is closed, so that the refrigerant is in a solid state. Stay in the lower chamber. Even if the temperature in the hollow portion reaches the melting point of the refrigerant, the liquid-phase refrigerant remains in the lower chamber if the temperature is lower than the opening temperature of the temperature sensitive valve. Thereby, at the time of engine starting or low load operation, heat in the combustion chamber can be suppressed from being transmitted to the stem guide via the refrigerant and dissipated, and the temperature of the combustion chamber can be raised quickly.

  On the other hand, when the temperature in the hollow portion reaches the melting point of the refrigerant and reaches the opening operation temperature of the temperature sensitive valve, the temperature sensitive valve is opened. When the temperature sensitive valve is opened, the liquefied refrigerant moves to the upper chamber through the communication hole, and the refrigerant is stirred in the entire hollow portion. As a result, during high-load operation of the engine, the heat in the combustion chamber is transferred to the stem guide via the refrigerant and dissipated, so that the hollow valve is prevented from becoming too hot and the deterioration of the hollow valve is suppressed. be able to.

JP 2009-221974 A

  However, in the hollow valve described in Patent Document 1, since the temperature sensitive valve is in a closed state when the engine is cold started, the refrigerant remains in the umbrella portion. If the refrigerant stays in the umbrella part, the heat transfer efficiency of the umbrella part increases, and heat in the combustion chamber is radiated with high efficiency through the umbrella part and the valve seat with which the umbrella part contacts when the valve is closed. If it does so, temperature rise in a combustion chamber at the time of cold start will become slow, and there exists a possibility that combustion of fuel may become incomplete.

  The present invention has been made in view of such circumstances, and quickly raises the temperature in the combustion chamber by suppressing heat dissipation through the umbrella portion of the hollow valve and the valve seat during cold start of the engine. It is an object of the present invention to provide an engine valve device capable of performing the following.

  In order to solve the above-described problems, the present invention provides a shaft portion supported in a reciprocating manner by a stem guide provided in a cylinder head of an engine, and a valve seat provided at a lower end portion of the shaft portion when the valve is closed. A hollow valve is formed between the shaft portion and the umbrella portion, and a magnetic body capable of flowing in the hollow portion is enclosed in the hollow portion, and provided around the stem guide. An engine valve device is provided that includes the electromagnet provided and a control unit that controls energization of the electromagnet.

  According to the present invention, when the electromagnet is not energized, the magnetic body diffuses throughout the hollow portion as the hollow valve reciprocates, so the heat in the combustion chamber is efficiently transmitted through the umbrella portion, the magnetic body, and the valve seat. Heat is dissipated.

  On the other hand, in a state where the electromagnet is energized, the magnetic body in the hollow portion is attracted to the electromagnet and is held at a position inside the stem guide. As a result, since the magnetic body is not substantially present in the umbrella portion, the heat in the combustion chamber is hardly dissipated through the umbrella portion and the valve seat.

  That is, the heat transfer of the hollow valve can be arbitrarily controlled by turning on and off the electromagnet. Therefore, for example, by energizing the electromagnet during cold start of the engine, it is possible to suppress heat dissipation through the umbrella and the valve seat during cold start, and the combustion chamber is quickly heated to completely burn the fuel. Can be made. In addition, for example, by not energizing the electromagnet when the engine is in a high rotation and high load state, it is possible to promote heat dissipation through the umbrella part and the valve seat, preventing damage due to overheating of the hollow valve and the valve seat, The durability of the engine can be improved.

  The present invention comprises an intake valve and an exhaust valve that are the hollow valves, an intake side electromagnet that is the electromagnet corresponding to the intake valve, and an exhaust side electromagnet that is the electromagnet corresponding to the exhaust valve, and the control Preferably, the unit individually controls energization to the intake-side electromagnet and energization to the exhaust-side electromagnet.

  According to this configuration, the heat dissipation efficiency of the intake valve and the heat dissipation efficiency of the exhaust valve can be individually controlled.

  In this invention, it is preferable that the said control part performs the control which supplies with electricity to the said intake side electromagnet and the said exhaust side electromagnet at the time of the cold start of an engine.

  According to this configuration, when the engine is cold-started, the heat release efficiency of the intake valve and the exhaust valve is reduced, so that the temperature in the combustion chamber can be quickly raised and the fuel can be completely burned more reliably. it can.

  In the present invention, it is preferable that the control unit performs control to energize the exhaust-side electromagnet while not energizing the intake-side electromagnet during warm start of the engine.

  According to this configuration, at the time of warm start of the engine, heat of the intake valve is efficiently given to the intake air to increase the temperature of the intake air, while reducing the heat dissipation efficiency of the exhaust valve, thereby adjusting the intake air temperature in the combustion chamber to an appropriate temperature. The fuel can be burned appropriately by controlling.

  In the present invention, the cylinder head is provided with a plurality of the hollow valves and electromagnets corresponding to the hollow valves, and further includes a power feeding circuit that supplies power to the electromagnets. It is preferable to include a common power feeding circuit common to the electromagnets corresponding to at least two hollow valves among the plurality of hollow valves.

  According to this configuration, by sharing the power feeding circuit, the entire power feeding circuit can be simplified and configured compactly.

  In the present invention, the engine is an in-line four-cylinder engine having four cylinders arranged in a row, and the common power supply circuit corresponds to a hollow valve provided in the outer two cylinders of the four cylinders. An outer power feeding circuit common to the electromagnets to be operated, and an inner power feeding circuit common to the electromagnets corresponding to the hollow valves provided in the inner two cylinders, and the control unit includes the outer power feeding circuit and the inner power feeding circuit. It is preferable to control them individually.

  According to this configuration, the power feeding circuit common to the inner two cylinders and the power feeding circuit common to the outer two cylinders in the in-line four-cylinder engine can be individually controlled. The inner two cylinders tend to store heat more easily than the outer two cylinders, and the combustion temperature tends to be high. Therefore, by individually controlling these, the temperature of each hollow valve can be appropriately controlled.

  As described above, according to the present invention, it is possible to quickly raise the temperature in the combustion chamber by suppressing heat dissipation through the umbrella portion of the hollow valve and the valve seat during cold start of the engine.

It is sectional drawing which shows the valve apparatus in embodiment of this invention, and is a figure which shows the state by which the exhaust valve which is a hollow valve is opened, and the electromagnet is supplied with electricity. It is a figure which shows the state which the exhaust valve shown in FIG. 1 closes, and the electromagnet is connected. FIG. 2 is a diagram showing a state where an exhaust valve shown in FIG. 1 is opened and an electromagnet is not energized. FIG. 2 is a diagram showing a state where an exhaust valve shown in FIG. 1 is closed and an electromagnet is not energized. It is sectional drawing which shows the valve apparatus in embodiment of this invention, and is a figure which shows the state in which the intake valve which is a hollow valve is opened, and the electromagnet is supplied with electricity. FIG. 6 is a diagram showing a state where the intake valve shown in FIG. 5 is closed and an electromagnet is connected. FIG. 6 is a diagram showing a state where the intake valve shown in FIG. 5 is opened and the electromagnet is not energized. FIG. 6 is a diagram showing a state where the intake valve shown in FIG. 5 is closed and the electromagnet is not energized. (A) is a figure which shows the structure of the electric power feeding circuit which supplies electric power to the electromagnet corresponding to an exhaust valve, (b) is a figure which shows the structure of the electric power feeding circuit which supplies electric power to the electromagnet corresponding to an intake valve. It is a graph which shows the relationship between the energization state to the exhaust side electromagnet and the intake side electromagnet in embodiment of this invention, the load concerning an engine, and an engine speed. It is a flowchart which shows the control by ECU in this embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  The engine in this embodiment is an in-line four-cylinder engine having four cylinders (not shown) arranged in a row. The four cylinders are arranged in order from one side as a first cylinder, a second cylinder, a third cylinder, and a fourth cylinder. Each cylinder is provided with two exhaust valves 1A (see FIGS. 1 to 4) and two intake valves 1B (see FIGS. 5 to 8).

  The valve device of the engine according to the present embodiment supplies power to the exhaust valve 1A and the intake valve 1B, the exhaust side electromagnet 7 corresponding to the exhaust valve 1A, the intake side electromagnet 7 corresponding to the intake valve 1B, and the exhaust side electromagnet 7. The exhaust side power supply circuit 17 (see FIG. 9A), the intake side power supply circuit 18 that supplies power to the intake side electromagnet 7 (see FIG. 9B), the exhaust side power supply circuit 17 and the intake side power supply circuit 18 are controlled. ECU (Electronic Control Unit, control part) 14 (refer Fig.9 (a) (b)) is provided.

  Hereinafter, each component will be described in detail.

<Configuration of exhaust valve 1A>
As shown in FIGS. 1 to 4, the exhaust valve 1 </ b> A includes a shaft portion 2, an umbrella portion 3, and iron powder (magnetic material) 5.

  The shaft portion 2 extends in the vertical direction, and is supported by a cylindrical stem guide 6 provided in the cylinder head 8 of the engine so as to be able to reciprocate in the vertical direction. A hollow hole extending from the vicinity of the upper end portion of the shaft portion 2 to the lower end portion is formed in the shaft portion 2.

  The umbrella part 3 is formed in a conical shape that gradually increases in diameter from the upper end part to the lower end part, and the upper end part is provided integrally with the lower end part of the shaft part 2. A conical hollow hole is formed in the umbrella portion 3. The hollow hole communicates with the hollow hole of the shaft portion 2. A hollow portion 4 extending from the shaft portion 2 to the umbrella portion 3 is constituted by the hollow hole in the shaft portion 2 and the hollow hole in the umbrella portion 3.

  The lower end 3a of the side surface of the umbrella 3 contacts the valve seat 10 located at the upstream end of the exhaust port 9 when the valve is closed. During this contact, the heat accumulated in the umbrella part 3 is radiated through the valve seat 10.

  The shaft portion 2 and the umbrella portion 3 are made of a nonmagnetic material, specifically a nickel alloy based on nickel. Examples of the metal element added to nickel include iron, chromium, niobium, and molybdenum. The stem guide 6 is also made of the same material.

  The iron powder 5 is a magnetic body enclosed in the hollow portion 4. The iron powder 5 can flow in the hollow portion 4.

<Configuration of exhaust-side electromagnet 7>
As shown in FIGS. 1 to 4, the exhaust-side electromagnet 7 is configured by a coil wound around the stem guide 6. An exhaust-side power feeding circuit 17 (see FIG. 9A) is connected to the exhaust-side electromagnet 7. When the exhaust-side electromagnet 7 is energized by the exhaust-side power supply circuit 17, the iron powder 5 is attracted to the exhaust-side electromagnet 7 by the magnetic force generated by the exhaust-side electromagnet 7 and is held at a position inside the stem guide 6 (FIG. 1 and 2).

  On the other hand, when energization to the exhaust electromagnet 7 is stopped, the iron powder 5 flows in the hollow portion 4 and diffuses in the hollow portion 4 in accordance with the vertical movement of the exhaust valve 1A. Since the iron powder 5 is affected by gravity, the concentration of the iron powder 5 diffused in the hollow portion 4 tends to be higher in the umbrella portion 3 than in the shaft portion 2. In consideration of this tendency, iron powder 5 is shown only in the umbrella part 3 in FIGS. 3 and 4 showing a state in which the exhaust-side electromagnet 7 is not energized. The powder 5 diffuses.

<Configuration of exhaust-side power feeding circuit 17>
As shown in FIG. 9A, the exhaust-side power supply circuit 17 is an exhaust corresponding to the exhaust valve 1A provided in the outer two cylinders (first cylinder and fourth cylinder) among the four cylinders of the engine. An outer power feeding circuit 17a common to the side electromagnet 7 and an inner power feeding circuit 17b common to the exhaust side electromagnet 7 corresponding to the exhaust valve 1A provided in the two inner cylinders (second cylinder and third cylinder) are included.

  The outer power feeding circuit 17a has a structure in which the battery 13, the exhaust-side electromagnet 7 corresponding to the first cylinder, the exhaust-side electromagnet 7 corresponding to the fourth cylinder, and the switch 12 are connected in series via a wiring. ing.

  The inner power feeding circuit 17b has a structure in which the battery 13, the exhaust electromagnet 7 corresponding to the second cylinder, the exhaust electromagnet 7 corresponding to the third cylinder, and the switch 12 are connected in series via wiring. ing.

  In the outer power feeding circuit 17a and the inner power feeding circuit 17b, the switch 12 is turned on / off based on a control signal sent from the ECU.

<Configuration of ECU 14>
The ECU 14 is composed of a CPU, RAM, ROM and the like. A crank angle sensor 15, an accelerator opening sensor 16, and a water temperature sensor 19 are connected to input terminals of the ECU 14 via a communication line. The crank angle sensor 15 is a sensor that detects the rotation angle of the crankshaft of the engine. The accelerator opening sensor 16 is a sensor that detects the amount of depression of the accelerator pedal by the driver. The water temperature sensor 19 is a sensor that detects the coolant temperature at a predetermined position in the cylinder head 8.

  An output terminal of the ECU 14 is connected to the switch 12 via a communication line. The ECU 14 performs a predetermined calculation based on signals received from the crank angle sensor 15, the accelerator opening sensor 16, and the water temperature sensor 19, and transmits a control signal for controlling on / off of the switch 12.

<Configuration of intake valve 1B>
As shown in FIGS. 5 to 8, the intake valve 1 </ b> B includes a shaft portion 2, an umbrella portion 3, and iron powder (magnetic material) 5. Since the configuration of the intake valve 1B is the same as the configuration of the exhaust valve 1A, detailed description thereof is omitted.

<Configuration of intake-side electromagnet 7>
As shown in FIGS. 5 to 8, the intake-side electromagnet 7 is configured by a coil wound around the stem guide 6. An intake side power supply circuit 18 (see FIG. 9B) is connected to the intake side electromagnet 7. When the intake-side electromagnet 7 is energized by the intake-side power supply circuit 18, the iron powder 5 is attracted to the intake-side electromagnet 7 by the magnetic force generated by the intake-side electromagnet 7 and is held at a position inside the stem guide 6 (FIG. 5 and 6).

  On the other hand, when the energization to the intake side electromagnet 7 is stopped, the iron powder 5 flows in the hollow portion 4 and diffuses in the hollow portion 4 in accordance with the vertical movement of the intake valve 1B. 7 and 8, the iron powder 5 is illustrated only in the umbrella portion 3 for the same reason as the exhaust valve 1 </ b> A, but the iron powder 5 actually diffuses also in the shaft portion 2.

<Configuration of Intake Side Power Supply Circuit 18>
As shown in FIG. 9 (b), the intake-side power supply circuit 18 includes an intake valve corresponding to the intake valve 1B provided in the outer two cylinders (first cylinder and fourth cylinder) among the four cylinders of the engine. An outer power feeding circuit 18a common to the side electromagnet 7 and an inner power feeding circuit 18b common to the intake side electromagnet 7 corresponding to the intake valve 1B provided in the inner two cylinders (second cylinder and third cylinder) are included.

  The outer power feeding circuit 18a has a structure in which the battery 13, the intake side electromagnet 7 corresponding to the first cylinder, the intake side electromagnet 7 corresponding to the fourth cylinder, and the switch 12 are connected in series via wiring. ing.

  The inner feeding circuit 18b has a structure in which the battery 13, the intake-side electromagnet 7 corresponding to the second cylinder, the intake-side electromagnet 7 corresponding to the third cylinder, and the switch 12 are connected in series via wiring. ing.

  In the outer power supply circuit 18 a and the inner power supply circuit 18 b, the switch 12 is turned on / off based on a control signal sent from the ECU 14.

  Next, control of the exhaust-side electromagnet 7 and the intake-side electromagnet 7 by the ECU 14 will be described with reference to FIGS.

  A broken line L1 shown in FIG. 10 indicates a region (lower side) indicating the engine speed and engine load (driving torque generated in the engine) when starting the engine, and the engine speed and engine load other than when starting the engine. It is a line which shows the boundary with an area | region (upper side). A solid line L2 indicates a boundary between a region where the energization to the exhaust side electromagnet 7 is turned on (lower side) and a region where the power supply to the exhaust side electromagnet 7 is turned off (upper side) from the viewpoint of durability of the exhaust valve 1A. Is a line. A solid line L3 indicates a boundary between a region where the energization to the intake side electromagnet 7 is turned on (lower side) and a region where the energization to the intake side electromagnet 7 is turned off (upper side) from the viewpoint of durability of the intake valve 1B. Is a line.

  As shown in FIG. 10, when the horizontal axis is the engine speed and the vertical axis is the engine load, the broken line L1, the solid line L2, and the solid line L3 are all linearly descending straight lines. Yes. In the broken line L1, the solid line L2, and the solid line L3, the engine speed and the engine load are gradually increased in this order.

  As shown in the flowchart of FIG. 11, first, the ECU 14 inputs signals indicating detection values from the crank angle sensor 15, the accelerator opening sensor 16, and the water temperature sensor 19 (step S1).

  Next, the ECU 14 calculates the engine speed based on the detection value input from the crank angle sensor 15 (step S2).

  Next, the ECU 14 calculates a load applied to the engine based on the detection value input from the accelerator opening sensor 16 (step S3).

  Next, the ECU 14 determines whether the engine is in a cold state before completion of warm-up or in a warm state after completion of warm-up based on the detection value input from the water temperature sensor 19 (step S4). .

  When the ECU 14 determines in step S4 that the engine is in a cold state (during cold start) (YES in step S4), the exhaust side as shown in the lower area of the broken line L1 in FIG. Control for energizing the electromagnet 7 and the intake-side electromagnet 7 (switch 12 is turned on) is performed (step S5).

  By performing the control in step S5, the iron powder 5 in the hollow portion 4 of the exhaust valve 1A is attracted to the exhaust-side electromagnet 7 and held at a position inside the stem guide 6 (see FIGS. 1 and 2). Further, the iron powder 5 in the hollow portion 4 of the intake valve 1B is attracted to the intake-side electromagnet 7 and held at a position inside the stem guide 6 (see FIGS. 5 and 6). Thereby, in the exhaust valve 1A and the intake valve 1B, the iron powder 5 is not substantially present in the umbrella part 3, and a heat insulation layer is formed in the umbrella part 3 so that the heat in the combustion chamber is transferred to the umbrella part 3. In addition, heat is not easily radiated through the valve seat 6. Thereby, the heat radiation (heat loss) through the umbrella part 3 and the valve seat 6 at the time of cold start is suppressed, and the temperature in the combustion chamber can be quickly raised to completely burn the fuel.

  On the other hand, if the ECU 14 determines that the engine is in a warm state in step S4 (NO in step S4), the relationship between the engine speed and the engine load is in a region below the broken line L1 shown in FIG. Is determined (step S6).

  When the ECU 14 determines YES in step S6 (during warm start), the ECU 14 energizes the exhaust side electromagnet 7 (switch 12 is turned on) and does not energize the intake side electromagnet 7 (switch 12 is turned off). (Step S7).

  By performing the control in step S7, the iron powder 5 in the hollow portion 4 of the exhaust valve 1A is attracted to the exhaust-side electromagnet 7 and held at a position inside the stem guide 6 (see FIGS. 1 and 2). On the other hand, the iron powder 5 in the hollow portion 4 of the intake valve 1B diffuses throughout the hollow portion 4 (see FIGS. 7 and 8).

  As a result, in the exhaust valve 1A, the iron powder 5 is not substantially present in the umbrella part 3, so that the heat in the combustion chamber is hardly dissipated through the umbrella part 3 and the valve seat 6. Further, as the intake valve 1B reciprocates, the iron powder 5 in the intake valve 1B diffuses throughout the hollow portion 4, thereby improving the thermal conductivity of the exhaust valve 1A as a whole. As a result, the umbrella portion 3 The heat accumulated in the intake valve 1 </ b> B through the iron powder 5 and the valve seat 10 is efficiently transmitted to the intake air introduced from the intake port 11.

  Therefore, at the time of warm start, the intake valve 1B efficiently heats the intake air, suppresses heat dissipation through the umbrella portion 3 and the valve seat 10 of the exhaust valve 1A, controls the combustion chamber to an appropriate temperature, and burns the fuel appropriately. be able to.

  If the determination in step S6 is NO, the ECU 14 determines whether the relationship between the engine speed and the engine load is in a region below the solid line L2 shown in FIG. 10 (step S8).

  When the ECU 14 makes a determination of YES in step S8, the ECU 14 performs control to energize the exhaust-side electromagnet 7 and the intake-side electromagnet 7 (switch 12 is turned on) as shown in the area below the solid line L2 in FIG. Perform (step S9).

  By performing the control in step S9, heat dissipation through the umbrella portion 3 and the valve seat 6 is suppressed in the exhaust valve 1A and the intake valve 1B, and the fuel can be burned appropriately.

  If the determination in step S8 is NO, the ECU 14 determines whether the relationship between the engine speed and the engine load is in a region below the solid line L3 shown in FIG. 10 (step S10).

  If the ECU 14 makes a determination of YES in step S10, as shown in the area below the solid line L3 in FIG. 10, the ECU 14 stops energization of the exhaust-side electromagnet 7 (switch 12 is turned off), and the intake-side electromagnet 7 Is energized (switch 12 is turned on) (step S11).

  By performing the control in step S11, the iron powder 5 in the hollow portion 4 of the intake valve 1B is attracted to the intake-side electromagnet 7 and held at a position inside the stem guide 6 (see FIGS. 5 and 6). On the other hand, the iron powder 5 in the hollow portion 4 of the exhaust valve 1A diffuses throughout the hollow portion 4 (see FIGS. 3 and 4).

  Thereby, in the intake valve 1B, the iron powder 5 is not substantially present in the umbrella portion 3, and a heat insulating layer is formed in the umbrella portion 3 so that the heat in the combustion chamber is transferred to the umbrella portion 3 and the valve seat 6. It becomes difficult to dissipate heat. Further, as the exhaust valve 1A reciprocates, the iron powder 5 in the exhaust valve 1A diffuses throughout the hollow portion 4, thereby improving the thermal conductivity of the exhaust valve 1A as a whole. As a result, the umbrella portion 3 The heat accumulated in the exhaust valve 1A is radiated through the iron powder 5 and the valve seat 10.

  Accordingly, it is possible to prevent the exhaust valve 1A from being damaged due to overheating, suppress heat dissipation through the intake valve 1B, control the combustion chamber to an appropriate temperature, and appropriately burn the fuel.

  When the ECU 14 determines NO in step S10, the ECU 14 stops the energization of the exhaust-side electromagnet 7 and the intake-side electromagnet 7 (turns off the switch 12) as shown in the region above the solid line L3 in FIG. Is performed (step S12).

  By performing the control in step S12, the iron powder 5 in the hollow portion 4 of the exhaust valve 1A diffuses throughout the hollow portion 4 (see FIGS. 3 and 4). Further, the iron powder 5 in the hollow portion 4 of the intake valve 1B diffuses throughout the hollow portion 4 (see FIGS. 7 and 8).

  Thus, as the exhaust valve 1A reciprocates, the iron powder 5 in the exhaust valve 1A diffuses throughout the hollow portion 4, and thus accumulates in the exhaust valve 1A through the umbrella portion 3, the iron powder 5, and the valve seat 10. Heat is dissipated through the valve seat 10. Similarly, the heat accumulated in the intake valve 1B is dissipated through the umbrella portion 3, the iron powder 5, and the valve seat 10 of the intake valve 1B.

  Therefore, damage to the exhaust valve 1A and the intake valve 1B due to overheating can be prevented.

  As described above, according to the present embodiment, when the exhaust-side electromagnet 7 is not energized, the iron powder 5 diffuses throughout the hollow portion 4 as the exhaust valve 1A reciprocates. The heat in the combustion chamber is efficiently radiated through the iron powder 5 and the valve seat 10.

  On the other hand, in a state where the exhaust-side electromagnet 7 is energized, the iron powder 5 in the hollow portion 4 is attracted to the exhaust-side electromagnet 7 and is held at a position inside the stem guide 6. As a result, the iron powder 5 does not substantially exist in the umbrella portion 3, and therefore, heat in the combustion chamber is hardly dissipated through the umbrella portion 3 and the valve seat 10.

  That is, by turning on / off the energization of the exhaust side electromagnet 7, the heat transfer property of the exhaust valve 1A can be arbitrarily controlled. Therefore, for example, by energizing the exhaust-side electromagnet 7 at the time of cold start of the engine, it is possible to suppress heat dissipation through the umbrella portion 3 and the valve seat 10 at the time of cold start, and to quickly raise the temperature in the combustion chamber. The fuel can be burned completely. Further, for example, when the engine is in a high rotation and high load state, the exhaust-side electromagnet 7 is not energized, whereby heat dissipation through the umbrella portion 3 and the valve seat 10 can be promoted, and the exhaust valve 1A and the valve seat 10 are overheated. It is possible to improve the durability of the engine by preventing breakage due to. The same applies to the intake valve 1B.

  In the present embodiment, the ECU 14 individually controls energization of the intake-side electromagnet 7 and exhaust-side electromagnet 7, so that the heat dissipation efficiency of the intake valve 1B and the heat dissipation efficiency of the exhaust valve 1A are individually controlled. Can be controlled.

  In the present embodiment, the ECU 14 performs control to energize the intake-side electromagnet 7 and the exhaust-side electromagnet 7 when the engine is cold-started. Therefore, the heat dissipation efficiency of the intake valve 1B and the heat dissipation efficiency of the exhaust valve 1A. By reducing the temperature, the temperature in the combustion chamber can be raised quickly, and the fuel can be completely burned reliably.

  Further, in the present embodiment, the ECU 14 performs control to energize the exhaust-side electromagnet 7 while not energizing the intake-side electromagnet 7 when the engine is warm-started. By increasing the intake air temperature efficiently and reducing the heat dissipation efficiency of the exhaust valve 1A, the intake air temperature in the combustion chamber can be controlled to an appropriate temperature, and the fuel can be combusted appropriately.

  In the present embodiment, the exhaust-side outer power feeding circuit 17a includes the exhaust-side electromagnets 7 corresponding to the four exhaust valves 1A (two exhaust valves 1A of the first cylinder and two exhaust valves 1A of the fourth cylinder). Common power supply circuit. The exhaust-side inner power supply circuit 17b is a common power-feed circuit common to the exhaust-side electromagnets 7 corresponding to the four exhaust valves 1A (two exhaust valves 1A of the second cylinder and two exhaust valves 1A of the third cylinder). It has become. Therefore, by sharing the power feeding circuit, the entire power feeding circuit can be simplified and configured compactly. The same applies to the intake side.

  In the present embodiment, the ECU 14 individually controls the outer power feeding circuit 17a and the inner power feeding circuit 17b. Since the inner two cylinders are more likely to accumulate heat and the combustion temperature tends to be higher than the outer two cylinders, each of the exhaust valves 1A can be controlled by individually controlling the outer power supply circuit 17a and the inner power supply circuit 17b. The temperature can be appropriately controlled. The same applies to the intake side.

  In addition, in the said embodiment, although the iron powder 5 is enclosed in the hollow part 4, it is not restricted to this. For example, the hollow portion 4 may be filled with magnetic fluid or permanent magnet powder or particles.

  Further, in the above embodiment, the ECU 14 performs the on / off control of the switch 12 based on the detected values of the crank angle sensor 15, the accelerator opening sensor 16, and the water temperature sensor 19, but is not limited thereto. For example, in the cylinder head 8, a temperature switch (for example, a thermistor) that turns on and off in response to temperature may be connected to the wirings of the power supply circuits 17a, 17b, 18a, and 18. In this case, energization to each electromagnet 7 can be controlled by turning on and off the temperature switch based on the temperature in the cylinder head 8 (for example, the cooling water temperature in the cooling water channel).

1A Exhaust valve (hollow valve)
1B Intake valve (hollow valve)
2 Shaft part 3 Umbrella part 4 Hollow part 5 Iron powder (magnetic material)
6 Stem guide 7 Exhaust side electromagnet, Intake side electromagnet 8 Cylinder head 9 Exhaust port 10 Valve seat 11 Intake port 12 Switch 13 Battery 14 ECU
DESCRIPTION OF SYMBOLS 15 Crank angle sensor 16 Accelerator opening sensor 17 Exhaust side electric power feeding circuit 17a Exhaust side outer electric power feeding circuit 17b Exhaust side inner electric power feeding circuit 18 Intake side electric power feeding circuit 18a Intake side outer electric power feeding circuit 18b Intake side inner electric power feeding circuit

Claims (6)

A shaft portion supported in a reciprocating manner by a stem guide provided in the cylinder head of the engine and an umbrella portion provided at a lower end portion of the shaft portion that contacts the valve seat when the valve is closed. A hollow valve in which a hollow part is formed over the umbrella part, and a magnetic body capable of flowing in the hollow part is enclosed in the hollow part;
An electromagnet provided around the stem guide;
An engine valve device, comprising: a controller that controls energization of the electromagnet. An intake valve and an exhaust valve, which are the hollow valves;
An intake-side electromagnet that is the electromagnet corresponding to the intake valve and an exhaust-side electromagnet that is the electromagnet corresponding to the exhaust valve;
2. The engine valve device according to claim 1, wherein the control unit individually controls energization of the intake-side electromagnet and energization of the exhaust-side electromagnet. 3.   The engine valve device according to claim 2, wherein the control unit performs control to energize the intake-side electromagnet and the exhaust-side electromagnet when the engine is cold-started.   3. The engine valve according to claim 2, wherein the control unit performs control to energize the exhaust-side electromagnet while not energizing the intake-side electromagnet during warm start of the engine. apparatus. In the cylinder head, a plurality of the hollow valves and an electromagnet corresponding to each hollow valve are provided,
A power supply circuit for supplying power to the electromagnet;
5. The engine valve according to claim 1, wherein the power supply circuit includes a common power supply circuit common to electromagnets corresponding to at least two hollow valves among the plurality of hollow valves. 6. apparatus. The engine is an in-line four-cylinder engine having four cylinders arranged in a row,
Of the four cylinders, the common power feeding circuit includes an outer power feeding circuit common to an electromagnet corresponding to a hollow valve provided in the outer two cylinders, and an electromagnet corresponding to a hollow valve provided in the inner two cylinders. Including a common inner feeding circuit,
6. The valve device for an engine according to claim 5, wherein the control unit individually controls the outer power feeding circuit and the inner power feeding circuit.

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