JP3992000B2 - Intake / exhaust valve temperature estimation device and valve clearance amount estimation device for an internal combustion engine - Google Patents

Description

  The present invention relates to an apparatus for estimating the temperature of an intake / exhaust valve of an internal combustion engine and an apparatus for estimating a valve clearance amount.

In Patent Document 1, in the fuel supply amount control apparatus for an internal combustion engine, the temperature of the intake valve is set to the cooling water temperature immediately after the engine is started, and after the start, the accumulated value of the combustion energy (fuel amount) is obtained every time the fuel is burned. Accordingly, it is described that the temperature of the intake valve rises with a first-order lag with respect to the maximum combustion temperature.
JP-A-8-177556

However, in the apparatus described in Patent Document 1, the temperature response is approximated as a first-order lag in calculating the temperature of the intake valve even in a transient operation state, so that a large error may occur with the actual temperature of the intake valve. There is.
And, since the valve clearance amount, which is the gap between the cam and the valve, changes due to thermal deformation of the valve umbrella portion and the shaft portion, the intake air amount changes and various controls of the engine cannot be controlled properly. was there.

  The present invention has been made paying attention to such a problem, and an object of the present invention is to accurately calculate the temperature of the intake and exhaust valves when calculating the actual valve clearance amount.

  Therefore, in the present invention, the amount of heat received by the valve umbrella by the combustion gas, the amount of heat released from the valve umbrella, the amount of heat transferred from the valve umbrella to the valve shaft, and the amount of heat released from the valve shaft are calculated, respectively. The representative temperature of the valve umbrella is calculated based on the amount of heat radiated from the valve umbrella and the amount of heat transferred from the valve umbrella to the valve shaft, while the representative of the valve shaft is calculated based on the amount of heat transferred from the valve umbrella to the valve shaft and the amount of heat released from the valve shaft. Calculate the temperature.

  In the present invention, the valve clearance amount is calculated based on the valve umbrella representative temperature and the valve shaft representative temperature.

According to the present invention, there is an effect that the umbrella representative temperature and the shaft representative temperature of the intake / exhaust valve can be accurately calculated based on the change in the amount of heat received and radiated from the valve.
Further, according to the present invention, the valve clearance amount can be accurately calculated based on the valve umbrella representative temperature and the valve shaft representative temperature, and this can be reflected in various controls of the engine.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a control block diagram of a valve clearance amount estimating apparatus for an internal combustion engine. FIG. 2 is a simplified model diagram in the temperature estimation of the intake valve and the exhaust valve. FIG. 3 is a heat balance model diagram in the temperature estimation of the intake valve and the exhaust valve.
The valve clearance amount estimating device includes a valve umbrella heat receiving amount calculating means 1, a valve umbrella heat releasing amount calculating means 2, a moving heat amount calculating means 5, a valve shaft heat releasing amount calculating means 6, a valve umbrella representative temperature calculating means 7, and a valve shaft representative temperature calculating. Means 8 and valve clearance amount calculation means 9 are roughly divided and calculate the valve umbrella representative temperature Td and the shaft representative temperature Tax for the intake valve and the exhaust valve, respectively, and based on these representative temperatures Td and Tax. Estimate the valve clearance VCLR.

The valve umbrella heat receiving amount calculation means 1 calculates the amount of heat received by the valve umbrella by combustion gas Q′in (where “′” is the amount of change with respect to time (ie, Q ′ = dQ / dt), and so on).
The valve umbrella heat dissipation amount calculating means 2 calculates the heat dissipation amount Q′seat that radiates heat from the valve umbrella to the cooling water through the valve seat → valve umbrella → valve seat heat dissipation amount calculation means 3 and release by fuel vaporization in the valve umbrella. It comprises vaporization heat radiation amount calculation means 4 for calculating the amount of heat Q'fuel. Thereby, the amount of heat released from the valve umbrella to the outside is calculated.

Note that Q ′ fuel indicates the amount of heat released by fuel vaporization at the umbrella portion of the intake valve, and is considered only when a fuel injection valve is provided in the intake passage. For this reason, the vaporization heat radiation amount calculation means 4 is provided only when the fuel injection valve is provided in the intake passage.
The moving heat amount calculating means 5 calculates a heat amount Q′d-ax moving from the valve umbrella to the valve shaft.

The valve shaft heat radiation amount calculation means 6 has a valve shaft → valve guide heat radiation amount calculation means 6a, and thereby calculates a heat radiation amount Q′guide that radiates heat from the valve shaft to the cooling water via the valve guide.
The valve umbrella representative temperature calculating means 7 is a calculation result of the valve umbrella heat receiving amount calculating means 1, the valve umbrella heat radiation calculating means 2 and the moving heat calculating means 5, that is, the heat receiving amount Q′in of the valve umbrella, the valve umbrella to the valve seat. The representative temperature Td of the valve umbrella is calculated based on the amount of heat released Q'seat, the amount of heat released Q'fuel due to fuel vaporization in the valve umbrella, and the amount of heat Q'd-ax moving from the valve umbrella to the valve shaft.

  The valve shaft representative temperature calculation means 8 calculates the calculation results of the movement heat amount calculation means 5 and the valve shaft heat radiation amount calculation means 6, that is, the heat amount Q'd-ax moving from the valve umbrella to the valve shaft and the heat radiation amount Q from the valve shaft. Based on “guide”, the representative temperature Tax of the valve shaft is calculated. The valve umbrella representative temperature calculating means 7 and the valve shaft representative temperature calculating means 8 constitute an intake / exhaust valve temperature calculating device. Thus, the amount of heat released from the valve shaft to the outside is calculated.

The valve clearance amount calculating means 9 calculates the valve clearance amount VCLR based on the calculation results of the valve umbrella representative temperature calculating means 7 and the valve shaft representative temperature calculating means 8, that is, the valve umbrella representative temperature Td and the valve shaft representative temperature Tax. .
The calculation of the valve umbrella representative temperature Td, the valve shaft representative temperature Tax, and the valve clearance amount VCLR may be performed for only one of the intake valve and the exhaust valve.

Next, calculation of the valve umbrella representative temperature Td and the valve shaft representative temperature Tax for the intake and exhaust valves will be described using the representative temperature calculation flow shown in FIG. This calculation is performed every predetermined time (10 msec).
In step 1 (shown as “S1” in the figure, the same applies hereinafter), the amount of heat Q′d-ax moving from the valve umbrella to the valve shaft is expressed by the thermal conductivity λ, the representative temperatures Td in the valve umbrella and the valve shaft, Based on the distance x of the point indicating Tax, the previous valve umbrella representative temperature Td, the previous valve shaft representative temperature Tax, and the valve shaft area Ad-ax, the following equation is used.

Q′d−ax = λ ((Td−Tax) / x) · Ad−ax (1)
This corresponds to the moving heat amount calculation means 5. Note that the initial value of the amount of heat Q′d-ax moving from the valve umbrella to the valve shaft is 0. This is because immediately after the engine is started, the valve umbrella only receives heat from the combustion gas, and almost no heat is transmitted from the valve umbrella to the valve shaft.
Here, the thermal conductivity λ is calculated by linear approximation according to the valve temperature with reference to the thermal conductivity characteristic table according to the temperature change of the valve shown in FIG. The slope of the thermal conductivity λ in this table is determined by the valve material.

  Further, the distance x between the points indicating the representative temperatures Td and Tax between the valve umbrella and the valve shaft is as follows. As shown in FIG. The distance between the predetermined points. This distance x is calculated based on the distribution of the valve temperature. The valve shaft area Ad-ax is an area from the cross-sectional area Ad of the valve umbrella portion to the cross-sectional area Aax of the stem portion, as shown in (b).

  In step 2, the combustion gas temperature Tg is calculated. The combustion gas temperature Tg includes a combustion gas temperature Tgivc when the intake valve is closed, a combustion gas temperature Tgmax when the intake valve is closed, and a combustion gas temperature Tgevc when the exhaust valve is closed. These combustion gas temperatures Tgmax, Tgivc, Tgevc are calculated as described in Japanese Patent Application No. 2003-364099.

That is, the combustion gas temperature Tgivc when the intake valve is closed is calculated from the exhaust temperature Texh, the inert gas ratio MRESFR which is the ratio of the inert gas, and the collector internal temperature Tcol as shown in the following equation.
Tgivc = Texh × MRESFR + Tcol × (1-MRESFR) (2)
As shown in the following equation, the combustion gas temperature Tgmax at the maximum temperature is a temperature Tcmax at the end of compression of the combustion chamber (maximum temperature at the end of compression), a calorific value Q due to combustion, a total gas amount MASSC of the combustion chamber, and a combustion gas Calculated from the constant pressure specific heat Cp.

Tgmax = Tcmax + Q / (MASSC × Cp) (3)
The combustion gas temperature Tgevc when the exhaust valve is closed is calculated as the exhaust temperature Texh detected by the temperature sensor when the exhaust valve is closed (Tgevc = Texh).
Referring to FIG. 4 again, in step 3, the heat transfer coefficient h is calculated as the cylinder bore diameter d, the fuel injection amount TP, the engine speed Ne, and the adaptation constants C1, C2, C3 as shown in the following equation.

h = 110d− ^0.2 × TP ^0.27 × (Ne × C1 + TP × C2) ^0.8 × C3 (4)
Here, the adaptation constants C1, C2, and C3 correspond to the combustion gas temperature Tgivc when the intake valve is closed, the combustion gas temperature Tgmax when the intake valve is closed, and the combustion gas temperature Tgevc when the exhaust valve is closed, as shown in FIG. Apply the value.

In step 4, as shown in the following equation, the combustion gas temperatures Tgivc, Tgmax, and Tgevc calculated in step 2 are substituted for the combustion gas temperature Tg, respectively, and the amount of heat Q′inivc, Q that the combustion gas gives to the intake valve at each time point 'inmax, Q'inevc is calculated.
Q′inivc = h × (Tgivc−Td) × Ad (5)
Q′inmax = h × (Tgmax−Td) × Ad (6)
Q′inevc = h × (Tgevc−Td) × Ad (7)
In step 5, as shown in the following equation, the valve umbrella received heat amount Q′in is calculated from the average value of the heat amounts Q′inivc, Q′inmax, Q′inevc that the combustion gas gives to the intake valve at each time point.

Q′in = (Q′inivc + Q′inmax + Q′inevc) / 3 (8)
In step 6, as shown in the following equation, the heat dissipation coefficient Q'sat from the valve umbrella to the valve seat is calculated by multiplying the value obtained by subtracting the water temperature Tw from the valve umbrella representative temperature Td by the heat capacity coefficient M1.

Q′seat = (Td−Tw) × M1 (9)
Here, with respect to the heat capacity coefficient, the heat capacity coefficients M1 and M2 corresponding to the engine speed Ne are calculated with reference to the heat capacity coefficient calculation table shown in FIG. If the engine speed Ne is high, the heat capacity coefficients M1 and M2 show large values.
In step 7, as shown in the following equation, a heat capacity coefficient M2 is multiplied by a value obtained by subtracting the water temperature Tw from the valve shaft representative temperature Tax, thereby calculating a heat radiation amount Q′guide from the valve shaft to the valve guide.

Q′guide = (Tax−Tw) × M2 (10)
In step 8, as shown in the following equation, the heat release amount Q ′ fuel due to fuel vaporization in the valve umbrella is calculated by multiplying the fuel injection amount Ti and the fuel vaporization ratio X.
Q'fuel = Ti × X (11)
Note that the heat release amount Q'fuel due to fuel vaporization is considered only when fuel is injected from the fuel injection valve disposed in the intake passage.

In step 9, as shown in the following equation, the amount of heat received by the valve umbrella Q'in, the amount of heat released by fuel vaporization Q'fuel, the amount of heat released from the valve umbrella to the valve seat Q'seat, the amount of heat transferred from the valve umbrella to the valve shaft A temperature change ΔTd in the valve umbrella direction is calculated from Q′d-ax, the valve specific heat c, and the valve umbrella mass md shown in FIG.
ΔTd = Q′in− (Q′fuel + Q′seat + Q′d−ax) / md · c (12)
In step 10, the current valve umbrella representative temperature Td is calculated by adding the previous valve umbrella representative temperature Td (n-1) to the temperature change ΔTd in the valve umbrella direction as shown in the following equation. The initial value of Td (n-1) is the water temperature Tw.

Td = ΔTd + Td (n−1) (13)
In step 11, the amount of heat Q′d-ax moving from the valve umbrella to the valve shaft, the amount of heat radiation Q′guide from the valve shaft, the specific heat c of the valve, and the valve shaft mass max shown in FIG. Thus, the temperature change ΔTax in the valve shaft direction is calculated.
ΔTax = (Q′d−ax−Q′guide) / max · c (14)
In step 12, the current valve shaft representative temperature Tax is calculated by adding the previous valve shaft representative temperature Tax (n-1) to the temperature change ΔTax in the valve shaft direction as shown in the following equation. The initial value of Tax (n-1) is the water temperature Tw.

Tax = ΔTax + Tax (n−1) (15)
As described above, the valve umbrella representative temperature Td and the valve shaft representative temperature Tax are calculated.
Next, calculation of the valve clearance amount using these representative temperatures Td and Tax will be described below. The valve clearance amount is calculated as described in Japanese Patent Application No. 2003-185133, for example.

  Here, the intake valve and the exhaust valve are thermally expanded by the combustion gas when combustion is performed in the combustion chamber. The valve umbrella is deformed by being thermally expanded in the umbrella direction (radial direction) by the combustion gas. When the valve umbrella is deformed by thermal expansion, the valve umbrella is deformed in the umbrella direction by the amount of thermal deformation, and the valve umbrella portion in contact with the valve seat is pushed downward (combustion chamber side), so that the valve clearance amount increases.

On the other hand, the valve shaft thermally expands in the axial direction by the amount of heat that moves due to heat conduction from the valve umbrella. When the valve shaft is thermally expanded, the valve is deformed toward the cam by the amount of thermal deformation, so that the valve clearance is reduced.
Here, the amount of thermal deformation VCLRd in the valve axial direction due to the thermal deformation of the valve umbrella, as shown in the following equation, is the contact angle θ between the valve umbrella and the valve seat, the length of the valve umbrella in the umbrella direction (the diameter of the valve umbrella) ) Vd #, the thermal expansion coefficient THEXCd in the direction of the umbrella based on the valve material, the valve umbrella representative temperature Td, and the water temperature Tw.

VCLRd = 1/2 × tan θ × Vd # × THEXCd × (Td−Tw) (16)
The amount of thermal deformation VCLRax in the valve shaft direction due to the thermal deformation of the valve shaft is as follows. The axial direction length (stem portion length) Vax # of the valve shaft and the axial direction based on the valve material It is calculated from the coefficient of thermal expansion THEXCax, the valve shaft representative temperature Tax, and the water temperature Tw.

VCLRax = Vax # × THEXCax × (Tax−Tw) (17)
The valve clearance change amount VDCLR is calculated by subtracting the axial thermal deformation amount VCLRax due to the thermal deformation of the valve umbrella from the axial thermal deformation amount VCLRd due to the thermal deformation of the valve umbrella.
VDCLR = VCLRd−VCLRax (18)
Here, an amount VCLRSTD that compensates for the influence of the valve clearance amount due to thermal deformation of the cylinder head due to combustion in the combustion chamber is calculated.

Based on these, as shown in the following equation, the valve clearance amount VCLR is calculated by adding the valve clearance change amount VDCLR and the complementary amount VCLRSTD.
VCLR = VDCLR + VCLRSTD (19)
According to the present embodiment, in the intake / exhaust valve temperature estimation device for an internal combustion engine, the valve umbrella heat receiving amount calculation means 1 for calculating the heat receiving amount Q′in of the valve umbrella by the combustion gas, and the heat dissipation amount Q′seat from the valve umbrella. , Q ′ fuel, a valve umbrella heat dissipation amount calculating means 2, a moving heat amount calculating means 5 for calculating a heat amount Q′d-ax moving from the valve umbrella to the valve shaft, and a heat dissipation amount Q′guide from the valve shaft. Based on the valve shaft heat radiation amount calculation means 6 to be calculated, the heat receiving amount Q′in of the valve umbrella, the heat radiation amounts Q′seat and Q′fuel from the valve umbrella, and the heat amount Q′d-ax moving from the valve umbrella to the valve shaft. The valve umbrella representative temperature calculating means 7 for calculating the representative temperature Td of the valve umbrella, the amount of heat Q′d-ax moving from the valve umbrella to the valve shaft, and the amount of heat released Q′guide from the valve shaft. Temperature Ta Comprises a valve shaft representative temperature calculating unit 8 for calculating a. For this reason, the umbrella representative temperature Td and the shaft representative temperature Tax of the intake / exhaust valve can be accurately calculated based on the change in the amount of heat received and radiated from the valve.

  Further, according to the present embodiment, the moving heat amount calculation means 5 is based on the valve umbrella representative temperature Td, the valve shaft representative temperature Tax, and the distance x between the points indicating the representative temperatures Td and Tax on the valve umbrella and the valve shaft. The amount of heat Q′d-ax moving from the valve umbrella to the valve shaft is calculated. For this reason, even if the valve umbrella representative temperature Td and the valve shaft representative temperature Tax change with the passage of time, the transferred heat quantity Q′d-ax can be appropriately calculated with high accuracy from the valve temperature distribution.

Further, according to the present embodiment, the moving heat amount calculating means 5 sets the initial value of the heat amount Q′d-ax moving from the valve umbrella to the valve shaft to 0. For this reason, it can be considered that immediately after the engine is started, the valve umbrella receives only the amount of heat from the combustion gas, and the heat from the valve umbrella is hardly transmitted to the valve shaft.
Further, according to the present embodiment, the valve umbrella heat receiving amount calculation means 1 calculates the heat receiving amount Q′in of the valve umbrella based on the fuel injection amount TP, the engine speed Ne, and the combustion gas temperatures Tgivc, Tgmax, Tgevc. For this reason, the amount of heat received by the valve umbrella Q′in can be calculated appropriately according to the operating state.

  Further, according to the present embodiment, the valve umbrella heat dissipation amount calculating means 2 includes the valve umbrella → valve seat heat dissipation amount calculating means 3 for calculating the heat dissipation amount Q′seat that radiates heat from the valve umbrella to the cooling water via the valve seat. Then, the heat radiation amount from the valve umbrella is calculated based on the heat radiation amount Q′seat that radiates heat from the valve umbrella to the cooling water through the valve seat. For this reason, the heat dissipation from the valve umbrella can be accurately calculated.

  Further, according to the present embodiment, the valve umbrella heat dissipation amount calculation means 2 calculates the heat dissipation amount Q′seat that radiates heat from the valve umbrella to the cooling water via the valve seat, and the valve umbrella → valve seat heat dissipation amount calculation means 3; Vaporization heat dissipation amount calculation means 4 for calculating a heat dissipation amount Q'fuel due to fuel vaporization in the valve umbrella, and a heat dissipation amount Q'seat that radiates heat from the valve umbrella to the cooling water through the valve seat. The amount of heat released from the valve umbrella (Q'seat + Q'fuel) is calculated based on the amount of heat released by fuel vaporization Q'fuel. For this reason, the heat dissipation from the valve umbrella can be calculated with higher accuracy.

Further, according to the present embodiment, the vaporized heat release amount calculation means 4 calculates the heat release amount Q′fuel due to fuel vaporization at the intake valve based on the fuel injection amount Ti and the fuel vaporization ratio X. For this reason, it is possible to accurately calculate the heat dissipation amount Q ′ fuel due to the fuel vaporized from the umbrella portion of the intake valve according to the operating state.
Further, according to the present embodiment, the valve shaft heat radiation amount calculation means 6 includes the valve shaft → valve guide heat radiation amount calculation means 6a for calculating the heat radiation amount Q'guide that radiates heat from the valve shaft to the cooling water via the valve guide. Then, the heat radiation amount Q′guide from the valve shaft is calculated based on the heat radiation amount Q′guide that radiates heat from the valve shaft to the cooling water through the valve guide. For this reason, it is possible to accurately calculate the amount of heat released from the valve shaft to the outside.

Further, according to the present embodiment, the valve umbrella heat dissipation amount calculation means 2 calculates the valve umbrella heat dissipation amount Q′seat based on the valve umbrella representative temperature Td, the water temperature Tw, and the engine speed Ne. For this reason, the heat dissipation amount Q′seat of the valve umbrella can be accurately calculated according to the operating state.
Further, according to the present embodiment, the valve shaft heat radiation amount calculation means 6 calculates the valve shaft heat radiation amount Q′guide based on the valve shaft representative temperature Tax, the water temperature Tw, and the engine speed Ne. For this reason, the heat dissipation amount Q′guide of the valve shaft can be accurately calculated according to the operating state.

  According to the present embodiment, the above-described intake / exhaust valve temperature estimation device for an internal combustion engine, and the valve clearance amount calculation for calculating the valve clearance amount VCLR based on the valve umbrella representative temperature Td and the valve shaft representative temperature Tax estimated thereby. Means 9. For this reason, the valve clearance amount VCLR can be accurately calculated in consideration of the valve umbrella representative temperature Td and the valve shaft representative temperature Tax. The valve clearance VCLR can be reflected in various engine controls.

Control configuration diagram of valve clearance amount estimation device for internal combustion engine Simplified model diagram for temperature estimation of intake and exhaust valves Calorific value balance model for temperature estimation of intake and exhaust valves Typical temperature calculation flow Thermal conductivity characteristics table according to valve temperature change Diagram showing temperature calculation distance between valve umbrella and valve shaft Applicable constant calculation table Heat capacity coefficient calculation table

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Valve umbrella received heat amount calculation means 2 Valve umbrella heat radiation amount calculation means 3 Valve umbrella → Valve seat heat release amount calculation means 4 Evaporation heat release amount calculation means 5 Moving heat amount calculation means 6 Valve shaft heat release amount calculation means 6a Valve shaft → Valve guide heat release amount Calculation means 7 Valve umbrella representative temperature calculation means 8 Valve shaft representative temperature calculation means 9 Valve clearance amount calculation means

Claims (11)

In the intake and exhaust valve temperature estimation device for an internal combustion engine,
A valve umbrella heat receiving amount calculating means for calculating a heat receiving amount of the valve umbrella by the combustion gas;
A valve umbrella heat dissipation amount calculating means for calculating a heat dissipation amount from the valve umbrella;
A moving heat amount calculating means for calculating the amount of heat moving from the valve umbrella to the valve shaft;
A valve shaft heat dissipation amount calculating means for calculating a heat dissipation amount from the valve shaft;
A valve umbrella representative temperature calculating means for calculating a representative temperature of the valve umbrella based on an amount of heat received by the valve umbrella, an amount of heat released from the valve umbrella, and an amount of heat moving from the valve umbrella to the valve shaft;
A valve shaft representative temperature calculating means for calculating a representative temperature of the valve shaft based on the amount of heat moving from the valve umbrella to the valve shaft and the amount of heat released from the valve shaft;
An intake / exhaust valve temperature estimation device for an internal combustion engine, comprising:   The moving heat amount calculating means calculates the amount of heat moving from the valve umbrella to the valve shaft based on the valve umbrella representative temperature, the valve shaft representative temperature, and the distance between the points indicating the representative temperatures of the valve umbrella and the valve shaft. The intake / exhaust valve temperature estimation device for an internal combustion engine according to claim 1, wherein:   The intake / exhaust valve temperature estimation device for an internal combustion engine according to claim 1 or 2, wherein the moving heat amount calculation means sets an initial value of heat amount moving from the valve umbrella to the valve shaft to zero.   4. The valve umbrella heat receiving amount calculating means calculates the heat receiving amount of the valve umbrella based on a fuel injection amount, an engine speed and a combustion gas temperature. The intake / exhaust valve temperature estimation apparatus of an internal combustion engine as described. The valve umbrella heat dissipation amount calculating means includes:
A valve umbrella for calculating the amount of heat radiated from the valve umbrella to the cooling water through the valve seat → the valve seat radiation amount calculating means;
The internal combustion engine according to any one of claims 1 to 4, wherein a heat radiation amount from the valve umbrella is calculated based on a heat radiation amount radiated from the valve umbrella to the cooling water through a valve seat. Intake and exhaust valve temperature estimation device. The valve umbrella heat dissipation amount calculating means includes:
A valve umbrella for calculating the amount of heat released from the valve umbrella to the cooling water through the valve seat → the valve seat heat dissipation amount calculating means;
Vaporization heat dissipation amount calculating means for calculating a heat dissipation amount due to fuel vaporization in the valve umbrella,
The amount of heat released from the valve umbrella is calculated based on the amount of heat released from the valve umbrella to the cooling water through the valve seat and the amount of heat released by fuel vaporization in the valve umbrella. 4. The intake / exhaust valve temperature estimation device for an internal combustion engine according to any one of 4 above.   7. The intake / exhaust valve temperature estimation device for an internal combustion engine according to claim 6, wherein the vaporized heat release amount calculation means calculates a heat release amount due to fuel vaporization in the intake valve based on a fuel injection amount and a fuel vaporization ratio. The valve shaft heat dissipation amount calculating means includes:
There is a valve shaft → valve guide heat dissipation amount calculating means for calculating the heat dissipation amount radiated from the valve shaft to the cooling water through the valve guide,
The internal combustion engine according to any one of claims 1 to 7, wherein a heat radiation amount from the valve shaft is calculated based on a heat radiation amount radiated from the valve shaft to the cooling water through a valve guide. Intake and exhaust valve temperature estimation device.   9. The valve umbrella heat dissipation amount calculating means calculates a heat dissipation amount from the valve umbrella based on a valve umbrella representative temperature, a water temperature, and an engine speed. Intake / exhaust valve temperature estimation device for internal combustion engine.   10. The valve shaft heat radiation amount calculating means calculates a heat radiation amount from the valve shaft based on a valve shaft representative temperature, a water temperature, and an engine speed. Intake / exhaust valve temperature estimation device for internal combustion engine. An intake / exhaust valve temperature estimation device for an internal combustion engine according to any one of claims 1 to 10,
Valve clearance amount calculating means for calculating a valve clearance amount based on the valve umbrella representative temperature and the valve shaft representative temperature estimated by the intake / exhaust valve temperature estimating device;
A valve clearance amount estimation device for an internal combustion engine, comprising:

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