JP2004138468A - Oil temperature detector and controller for internal combustion engine using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately estimate oil temperature by solving a problem in a conventional engine oil estimation method that temperature estimation accuracy is practically poor in a vehicle-mounted state. <P>SOLUTION: This oil temperature detector has a heat radiation correcting value calculation means to calculate a heat radiation correcting value that represents a heat radiation portion from engine oil to outside air by using at least one of outside air temperature and vehicle speed, and estimates engine oil temperature by using the correcting value. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an oil temperature detection device and a control device for an internal combustion engine using the same.
[0002]
[Prior art]
In the control of an internal combustion engine, the necessity of the engine oil temperature has conventionally been low. However, with the advancement of the self-diagnosis system in recent years, there are increasing examples of using the signal thereof. For example, oil-diluted fuel that leaks from a gap between a piston and a cylinder and dilutes engine oil, when the leakage flow rate is large, becomes empty when the oil-diluted fuel evaporates from the engine oil and is drawn into the intake system from the blow-by system. It is known that the fuel ratio becomes excessively rich (fuel rich) and adversely affects fuel system diagnosis using the air-fuel ratio.
[0003]
Therefore, a technique for estimating the engine oil temperature using the engine rotation speed and the engine load based on the cooling water temperature has been proposed (see Patent Document 1).
[0004]
[Patent Document 1]
JP-A-08-177599 (page 2, FIG. 2)
[0005]
[Problems to be solved by the invention]
However, the conventional engine oil estimating method has a problem that the temperature prediction accuracy in a vehicle mounted state is actually poor. That is, in the case of a vehicle, the exchange of heat between the engine oil temperature and the water temperature is, of course, large, but in many cases, it cannot be determined only by the heat reception and heat radiation from the pistons and cylinders. Since the temperature and the wind speed contribute to the cooling of the oil, there is a problem that the influence of the vehicle speed and the outside air temperature becomes very large, and the accuracy of the temperature prediction deteriorates.
[0006]
[Means for Solving the Problems]
Therefore, the oil temperature detection device of the present invention has a heat radiation correction value calculation unit that calculates a heat radiation correction value that is a heat radiation amount from the engine oil to the outside air using at least one of the outside air temperature and the vehicle speed. , The engine oil temperature is estimated using the heat radiation correction value.
[0007]
【The invention's effect】
According to the present invention, the accuracy of the engine oil temperature can be improved by estimating the engine oil temperature using the heat radiation from the engine oil to the outside air.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a schematic configuration of a control device for an internal combustion engine according to one embodiment of the present invention. An intake passage 4 is connected to the combustion chamber 2 of the engine body 1 via an intake valve 3, and an exhaust passage 6 is connected to the combustion chamber 2 via an exhaust valve 5.
[0009]
In the intake passage 4, an air cleaner 7, an air flow meter 8 for detecting an intake air amount, a throttle valve 9 for controlling the intake air amount, and a fuel injection valve 11 for injecting fuel during intake are arranged.
[0010]
The fuel injection valve 11 injects and supplies fuel during intake so as to attain a predetermined air-fuel ratio in accordance with an operation condition by an injection command signal from an engine control unit 12 (hereinafter, referred to as ECU).
[0011]
An oxygen concentration sensor 13 for detecting the oxygen concentration in the exhaust gas and a three-way catalyst 14 are provided in the exhaust passage 6.
[0012]
The three-way catalyst 14 can simultaneously purify NOx, HC, and CO in exhaust gas with the maximum conversion efficiency when the air-fuel ratio is in a so-called window centered on the stoichiometric air-fuel ratio. Based on the output from the oxygen concentration sensor 13 provided in the above, feedback control of the air-fuel ratio is performed so that the exhaust air-fuel ratio fluctuates at a constant cycle within the above-mentioned window.
[0013]
The ECU 12 also includes a water temperature sensor 15 for detecting the temperature of the cooling water of the engine body 1, a crank angle sensor 16 for detecting the engine speed, an outside air temperature sensor 17 for detecting the outside air temperature, and an oil level in the oil pan. Signals from an oil level sensor 18 and a vehicle speed sensor 19 for detecting the vehicle speed are input.
[0014]
Here, during the operation of the engine, when a part of the fuel adheres to the inner wall surface of the cylinder and leaks from the gap between the piston and the cylinder to dilute the engine oil, so-called oil dilution occurs. If the diluted fuel evaporates from the engine oil and is drawn into the intake system from the blow-by system or the like, the air-fuel ratio becomes excessively rich (fuel rich), which may adversely affect drivability and exhaust performance. There is.
[0015]
Since the evaporation of the oil dilution fuel from the engine oil greatly depends on the oil temperature of the engine oil, the engine oil temperature detection device according to the first embodiment of the present invention estimates the oil temperature TO of the engine oil by the following procedure.
[0016]
FIG. 2 is a flowchart showing a control flow of the engine oil temperature detecting device according to one embodiment of the present invention.
[0017]
In step 11 (hereinafter simply referred to as S), it is determined whether or not the engine has been started or the ECU 12 has been initially energized. To make the value of TO ₀ the same as the engine cooling water temperature Tw.
[0018]
If it is determined in S11 that it is neither when the engine is started nor when the ECU 12 is first energized, the process proceeds to S13.
[0019]
In S13, the heat flow TTW between the engine oil and the engine coolant is calculated from the following equation using the engine coolant temperature Tw, TTWS, and the oil temperature TOn _-1 at the previous calculation.
[0020]
(Equation 1)
TTWn = (Tw−TO _n−1 ) × TTWS (1)
That is, since the heat transfer amount is proportional to the temperature difference and is a function of the flow velocity, it is obtained by multiplying the TTWS obtained from the engine speed Ne.
[0021]
FIG. 3 shows a characteristic example of the TTWS calculation table. TTWS becomes a large value in proportion to the engine speed Ne. Here, when calculating the TTWS, the engine speed Ne was used because the engine coolant or the cylinder block and the cylinder head in contact with the engine coolant and the heat transfer between the engine oil and the engine oil were performed by turning the oil pump. This is because the rotation speed is proportional to Ne. In addition, there is a portion that is transmitted through the oil pan, but this can be dealt with by appropriately fitting a clog to the characteristics shown in FIG.
[0022]
In S14, the heat flow TTC (heat receiving correction value) between the engine oil and the combustion is calculated from the following equation using the engine coolant temperature Tw, TTCT, and TTCN.
[0023]
(Equation 2)
TTC _n = (TTCT−TO _n−1 ) × TTCN (2)
Here, FIG. 4 shows a characteristic example of the TTCT calculation table, and FIG. 5 shows a characteristic example of the TTCN calculation table. TTCT is the temperature of the piston cylinder wall, and is related to the combustion temperature. Therefore, TTCT is obtained from the calculation table of FIG. 4 using the product of the fuel injection amount Te and the engine speed Ne. Note that the fuel injection amount Te is determined according to the operating state. TTCN is the engine oil flow velocity for heat transfer, which is obtained from the calculation table in FIG. 5 using the engine speed Ne.
[0024]
In S15, a heat radiation amount TTA (heat radiation correction value) from the engine oil to the outside air is calculated from the following equation.
[0025]
[Equation 3]
TTA _n = (TO _n−1 −Ta) × TTAVSP (3)
Here, Ta is an outside air temperature which is an output signal of the outside air temperature sensor 17, and TTAVSP is a flow rate for heat transfer obtained from an output signal VSP (vehicle speed) of the vehicle speed sensor 18. FIG. 6 shows a characteristic example of the TTAVSP calculation table.
[0026]
In S16, the engine oil amount in the oil pan, that is, the oil level OL is read. The oil level OL is obtained by A / D-converting and reading the output voltage of the oil level sensor 18. As the oil level sensor 18, for example, a float + potentiometer system is known.
[0027]
In S17, the oil level correction factor KOL is calculated using the oil level OL read in S16. FIG. 7 shows a characteristic example of the calculation table of the oil level correction rate KOL.
[0028]
Then, in S18, the calculated oil temperature TO _n from the following equation.
[0029]
(Equation 4)
_{TO n = TO n-1 +} (TTWn + TTC n -TTA n) × KOL ... (4)
Formula for calculating the oil temperature TO _n shown in S18, the engine oil is warmed by the piston cylinder by the combustion and engine coolant, is an equation that models the phenomenon that is cooled by running wind (engine cooling water). However, since the heat capacity of the oil differs depending on the oil level OL, the rate at which the temperature rises and falls varies accordingly. For the correction, which multiplies the oil level correction factor KOL to the sum of the change in temperature _{(TTWn + TTC n -TTA n)} . Since the temperature change becomes slower as the oil level increases (increases), the characteristics of the calculation table of the oil level correction rate KOL shown in FIG. 7 are set so that the oil level correction rate KOL decreases as the oil level OL increases. .
[0030]
FIG. 8 shows the correlation among the engine coolant temperature Tw, the oil temperature TO, the heat flow TTW between the engine oil and the engine coolant, the heat flow TTC between the engine oil and the combustion, and the heat release TTA from the engine oil to the outside air. FIG.
[0031]
As shown in FIG. 8, when the temperature difference between the engine coolant temperature Tw and the oil temperature TO increases, the heat flow TTW between the engine oil and the engine coolant decreases. Also, as TO increases, the temperature difference between TTCT decreases, and the heat flow TTC between engine oil and combustion decreases. Then, when the vehicle starts running, the outside air temperature Ta becomes small (low), so the amount of heat radiation TTA from the engine oil to the outside air increases.
[0032]
In such an engine oil temperature detection device, the fuel flow TTW between the engine oil and the engine cooling water, the heat flow TTC between the engine oil and the combustion, the heat radiation TTA from the engine oil to the outside air, and the oil level OL are used. By using the oil level correction factor KOL, the oil temperature TO can be accurately estimated. More specifically, the heat radiation TTA from the engine oil to the outside air contributes to the improvement of the accuracy when the temperature of the engine oil is low, and the heat flow TTC between the engine oil and the combustion increases when the temperature of the engine oil is high. It contributes to improving accuracy.
[0033]
Therefore, it is possible to prevent erroneous diagnosis of the fuel system diagnosis performed using the oil temperature TO, regardless of the history of engine operation or the history of environmental change.
[0034]
Further, by calculating the oil temperature TO using the oil level correction factor KOL, the oil temperature TO is accurately estimated even in the case of an engine in which the amount of engine oil in the oil pan is large, corresponding to maintenance-free operation. can do. In addition, some oil level sensors are generally set for maintenance, and using them together does not increase the cost.
[0035]
In the oil temperature detecting device described above, the output signal of the outside air temperature sensor 17 is used as it is as the outside air temperature Ta when calculating the heat radiation TTA from the engine oil to the outside air, but the air heated by the radiator is used. May be used for the estimated oil surrounding temperature Tao instead of Ta used in S15 of FIG.
[0036]
The estimated oil surrounding temperature Tao is calculated according to the flowchart shown in FIG. 9, and first reads the outside air temperature Ta from the output signal of the outside air temperature sensor 17 in S21. In S22, the radiator temperature TL is calculated (details will be described later). Then, in step 23, the oil surrounding temperature Tao is calculated from the following equation.
[0037]
(Equation 5)
Tao = Ta + (TL−Ta) WT (5)
This equation (5) is an internal division equation for obtaining a value between the radiator temperature TL and the outside air temperature Ta, and the temperature rise coefficient WT means an internal division ratio.
[0038]
Here, the above-described radiator temperature TL is calculated according to the flowchart shown in FIG.
[0039]
In S31, it determines whether the time of starting the engine, in the case of starting the engine, the flow proceeds to S32, calculates an initial value TL ₀ radiator temperature TL. The initial value TL ₀ is estimated from the engine coolant temperature Tw and the outside air temperature Ta, be calculated using may be set such that the temperature between these temperatures, for example, FIG. 9 likewise internal ratio Just fine.
[0040]
In S33, the radiator temperature ratio TLHG is calculated from the calculation table shown in FIG. 11 using the engine coolant temperature Tw. The radiator temperature ratio TLHG is an internal division coefficient that means what percentage of the radiator temperature equilibrium value is between the outside air temperature Ta and the engine cooling water temperature Tw.
[0041]
In S34, the radiator temperature equilibrium value THL is calculated from the following equation using the outside air temperature Ta, the engine cooling water temperature Tw, the radiator temperature ratio TLHG, and the vehicle speed cooling coefficients KVSP and D.
[0042]
(Equation 6)
_{TLH n = Ta + (Tw-} Ta) TLHG-KVSP (TL n-1 -Ta) ... (6)
Here, KVSP (TL _n−1 −Ta) in the equation (6) is a temperature reduction amount for cooling by the vehicle speed wind, and the vehicle cooling coefficient KVSP calculated from the calculation table of FIG. 12 using the vehicle speed VSP. And the temperature difference between the previous radiator temperature TL _n−1 and the outside air temperature Ta.
[0043]
Then, in S35, the radiator temperature TL is calculated from the following equation.
[0044]
(Equation 7)
TL = TLn _-1 + (TLH-TLn _-1 ) KTL (7)
This is a temporary delay equation, and is a constant for KTL to determine a changing speed instead of a time constant.
[0045]
In addition, in a vehicle in which the wind of the radiator fan hits the oil pan a lot, the ON / OFF of the radiator fan is determined as shown in FIG. 13 to improve the accuracy of the oil temperature TO. The TTAVSP may be calculated from the TTAVSP calculation table of FIG. 6 described above by using the VSOP obtained by adding the predetermined value MFSP to the VSP instead of the vehicle speed VSP.
[0046]
That is, in S41, ON / OFF of the radiator fan is determined. When the radiator fan is ON, the process proceeds to S42, in which a predetermined value MFSP as a correction amount relating to the wind of the radiator fan hitting the oil pan is added to the vehicle speed VSP to calculate VSOP. When the radiator fan is OFF, the process proceeds to S43, where VSOP = VSP. Then, VTAVSP may be calculated from the TTAVSP calculation table shown in FIG. 6 by using the VSOP calculated in the flowchart shown in FIG. 13 instead of the VSP. Although the example of the electric fan is shown here, the influence of the air volume hitting the oil pan can be reduced by performing calculations in accordance with a two-system radiator fan or a mechanical radiant fan directly driven by a belt. . For example, in a mechanical fan, a correction value of the air volume to be added to the vehicle speed VSP according to the engine speed may be obtained.
[0047]
Next, a second embodiment of the present invention will be described. In the second embodiment, the engine performing the air-fuel ratio control is equipped with the oil temperature detection device according to the first embodiment described above, and the fuel injection pulse width is determined according to the oil temperature TO calculated by the oil temperature detection device. Correction of Ti is performed. The fuel injection pulse width Ti is calculated using the fuel injection amount Te determined according to the operating state of the engine.
[0048]
FIG. 14 is a flowchart showing a procedure for estimating the oil dilution fuel amount OF used for correcting the fuel injection pulse width Ti, which is executed at predetermined time intervals.
[0049]
In S51 comprising the first subroutine (details will be described later), an increase amount A of the oil dilution fuel amount is calculated.
[0050]
In S52 composed of the second subroutine (details will be described later), the reduction ratio B of the oil dilution fuel amount is calculated.
[0051]
In S53, the change amount COF of the oil dilution fuel amount is calculated using the increase amount A of the oil dilution fuel amount calculated in S51 and the decrease ratio B of the oil dilution fuel amount calculated in S52. Here, OF _n-1 is the oil dilution fuel amount calculated last time. Then, in S54, the oil dilution fuel amount OF is calculated.
[0052]
FIG. 15 shows a flow of control in the first subroutine described above.
[0053]
In S61, a fuel drop rate C, which is an increase rate of the increase amount A, is calculated with reference to a MOFD map (described later). FIG. 16 shows a characteristic example of the MOFD map. This MOFD map is for calculating the fuel drop rate C from the cylinder wall temperature TC and the engine speed Ne. The lower the engine speed, the larger the fuel drop rate C, and the lower the cylinder wall temperature TC. The lower the lower, the higher the fuel drop rate C. This is because it is considered that when the engine is running at a low speed, the gas flow is small, the fuel is poorly vaporized and atomized, and the fuel easily adheres to the wall surface. The cylinder wall temperature TC depends on the fuel volatilization characteristics.
[0054]
In S62, a load correction ratio D is calculated with reference to a load correction table (described later). FIG. 17 shows a characteristic example of the load correction table. The load correction table is for calculating a load correction rate D from a basic injection amount Tp (described later) obtained from an intake air amount Qa obtained from an output of the air flow meter 8 and an engine speed Ne as an engine load. As the unburned fuel ratio in the combustion chamber 2 increases, the load correction rate D increases. This is because it is considered that the fuel volatility changes depending on the pressure.
[0055]
In S63, the increase amount A is calculated using the fuel drop rate C, the load correction rate D, the engine speed Ne, and the fuel injection amount Te determined by the operating state of the engine as the engine load.
[0056]
The cylinder wall temperature TC used for calculating the fuel drop rate C may be an estimated value or a value obtained by directly detecting the temperature of the cylinder wall by embedding a temperature sensor in the cylinder.
[0057]
FIG. 18 shows a control flow in the second subroutine described above. In the second subroutine, in S71, a reduction ratio B, which is an evaporation rate of oil-diluted fuel from engine oil, is calculated with reference to a MOFU map (described later). FIG. 19 shows a characteristic example of the MOFU map. This MOFU map is used to calculate the decrease rate B from the oil temperature TO and the engine speed Ne, and the oil temperature TO is calculated according to the flowchart of FIG. 2 described above.
[0058]
The correlation between the decrease rate B and the oil temperature TO is such that the higher the oil temperature TO, the greater the decrease rate B due to the volatility of the fuel. In addition, the correlation between the decrease rate and the engine speed Ne is that the evaporation of the fuel in the engine oil is promoted by the oil stirring by the oil pump and the oil stirring by the counterweight of the crankshaft. The higher the rotation speed Ne, the greater the decrease rate B.
[0059]
Next, FIG. 20 shows a control flow of the control device of the internal combustion engine using the oil dilution fuel amount OF calculated using the oil temperature TO.
[0060]
In S91, the basic injection amount Tp is calculated. The basic injection amount Tp is calculated by multiplying the intake air amount per engine revolution (Qa / Ne) by a predetermined constant K using the engine speed Ne and the intake air amount Qa obtained from the output of the air flow meter 8. You. Here, the basic injection amount Tp is a representative value of the engine load, which is a basis for calculating the fuel injection amount Te described above.
[0061]
In S92, an air-fuel ratio correction coefficient KMR is calculated from a map to which the engine speed Ne and the throttle valve opening are assigned. The map for calculating the air-fuel ratio correction coefficient KMR is stored in the ECU 12 in advance.
[0062]
In S93, a water temperature increase correction coefficient KTW is calculated from the table to which the engine cooling water temperature Tw is allocated. The table for calculating the water temperature increase correction coefficient KTW is stored in the ECU 12 in advance.
[0063]
In S94, the target fuel-air ratio equivalent amount TFBYA is calculated from the following equation using the oil drop rate C and the load correction rate D.
[0064]
(Equation 8)
TFBYA = 1 + KMR + KTR + (C × D × GUB) (8)
Here, GUB is set so that GUB = (H1 + H2) / H2, where H1 is the discharge amount to the exhaust system and H2 is the oil dilution fuel amount. Value. In other words, the product of the oil drop rate C and the load correction rate D is multiplied by GUB because the fuel adhering to the cylinder wall includes fuel that is scraped by the piston and becomes oil-diluted fuel that dilutes engine oil, and burns. Some are discarded from the exhaust system, and are multiplied by a predetermined constant GUB in anticipation of that amount.
[0065]
In S95, the fuel injection amount Te is calculated from the following equation.
[0066]
(Equation 9)
Te = Tp × TFBYA × α × αm × KTR (9)
Here, α is an air-fuel ratio feedback correction coefficient, which is calculated based on the output signal of the oxygen concentration sensor 13 by a flowchart different from this flowchart. Αm is an air-fuel ratio learning correction coefficient calculated based on the above α, and KTR is a transient correction coefficient representing a correction amount of wall-flow fuel.
[0067]
In S96, the fuel injection pulse width Ti, which is the pulse width required to inject the above-described fuel injection amount Te, is calculated from the following equation.
[0068]
(Equation 10)
Ti = Te × KWJ + Ts (10)
Here, KWJ is an injection amount correction coefficient, and Ts is an invalid pulse width which is a correction amount of a difference between the energization time of the fuel injection valve 11 and the actual injection time.
[0069]
Then, in S97, the fuel injection pulse width Ti is output, and the fuel injection valve 11 is controlled to perform fuel injection with the fuel injection pulse width Ti.
[0070]
As described above, in the control device of the internal combustion engine using the oil temperature TO as a control parameter of the fuel injection pulse width Ti, the accuracy of the oil temperature TO affects the accuracy of the fuel injection pulse width Ti. That is, by improving the accuracy of the oil temperature TO, the accuracy of the fuel injection pulse width Ti can be improved.
[0071]
Next, a third embodiment of the present invention will be described.
[0072]
Currently, many cars can burn gasoline with low levels of alcohol. In recent years, a so-called flexible fuel vehicle (FFV), which can run on a mixed fuel of various compositions of alcohol and gasoline in addition to gasoline, has become widely known.
[0073]
In such a flexible fuel vehicle (FFV), a system that does not use an alcohol concentration sensor is realized. In this case, the alcohol concentration is estimated using a change in the air-fuel ratio, and the fuel evaporated from the oil is disturbed. Therefore, an accurate value of the engine oil temperature, which is an important parameter of fuel evaporation, is desired.
[0074]
Therefore, in the third embodiment, a case will be described in which the techniques of the first and second embodiments described above are applied to an internal combustion engine using a fuel containing alcohol.
[0075]
Alcohol fuel requires a large injection amount to obtain the same equivalence ratio as gasoline, based on the number of atoms of C (carbon), H (hydrogen), and O (oxygen). Therefore, using the detection value of the oxygen concentration sensor 13, the alcohol concentration in the fuel is predicted as quickly and accurately as possible.
[0076]
FIG. 21 is a flowchart showing a control flow of the alcohol concentration estimation using the oil temperature TO in the third embodiment.
[0077]
In S101, the air-fuel ratio feedback correction coefficient α calculated based on the output signal of the oxygen concentration sensor 13 is read by a flowchart different from the present flowchart.
[0078]
In S102. It is determined whether or not the learning condition is satisfied. If the learning condition is satisfied, the process proceeds to S103, and the map value of the αm calculation map for each operation region is rewritten. If the learning condition is not satisfied, the process proceeds to S104 without rewriting the map value of each αm map value.
[0079]
In S104, αm for each operating region is determined with reference to the current αm map for each operating region.
[0080]
Next, in S105, it is determined whether or not the oil dilution fuel amount OF calculated in the above-described flowchart of FIG. 14 is smaller than a predetermined estimated allowable dilution amount LOF #.
[0081]
In S106, it is determined whether or not the absolute value of the change amount COF calculated in the above-described flowchart of FIG. 14 is smaller than a predetermined estimated allowable dilution change amount LCOF #.
[0082]
In S105 and S106, when the absolute values of the oil dilution fuel amount OF and the change amount COF are both smaller than the target values (LOF♯ and LCOF♯), it is considered that the influence of the fuel evaporated from the engine oil is small, and the alcohol concentration is estimated. In the alcohol concentration estimation, other permission conditions (S107) are necessary. In the present embodiment, the engine cooling water temperature, the time after engine start, the progress of the air-fuel ratio learning control, When conditions such as the refueling history are satisfied, the alcohol concentration is estimated.
[0083]
In S108, the average value of αm in the representative rotational load region among αm in each operation region is calculated. That is, the average value of αm in about four regions is calculated, and the result is used to calculate the alcohol concentration from the table shown in FIG. Here, the above-mentioned four regions are regions where the frequency of use as the engine is relatively high and a region where the amount of intake air is not too small is selected. This region secures the learning frequency and evaporates from the engine oil, for example. This is to select a relatively large air amount region that is not easily affected by the oil dilution fuel.
[0084]
In FIG. 22, the alcohol concentration has a characteristic of having a dead zone with respect to the average value of αm. This is because when a gasoline is charged or when a standard blend fuel (gasoline-alcohol fuel) is used. If it is entered, it is a characteristic set to use a stable control value (control constant). Here, the control values include ignition timing-related, fuel wall flow correction-related, so-called λ control control ternary point adjustment constant, cooling increase-related, and the like. If these values fluctuate, emission reproducibility deteriorates. Therefore, it is a dead zone.
[0085]
Also in the third embodiment, by increasing the accuracy of the oil temperature TO, the alcohol concentration can be accurately estimated, and the exhaust performance and drivability of the flexible fuel vehicle can be improved.
[0086]
The technical ideas of the present invention that can be grasped from the above embodiments will be listed together with their effects.
[0087]
(1) The oil temperature detecting device has a heat radiation correction value calculating means for calculating a heat radiation correction value, which is a heat radiation amount from the engine oil to the outside air, using at least one of the outside air temperature and the vehicle speed. The engine oil temperature is estimated using the heat radiation correction value. Thereby, the accuracy of the engine oil temperature can be improved.
[0088]
(2) In the oil temperature detecting device according to the above (1), the heat receiving correction value calculating means for calculating a heat receiving correction value, which is a heat receiving component to the engine oil with the combustion of the internal combustion engine, using a signal related to the engine load. The engine oil temperature is estimated using the heat reception correction value and the heat release correction value. Thereby, the accuracy of the engine oil temperature can be further improved.
[0089]
(3) In the oil temperature detecting device according to (1) or (2), the estimated engine oil temperature is corrected according to the amount of engine oil in the oil pan. As a result, it is possible to accurately estimate the oil temperature even in an engine having a large oil amount change.
[0090]
(4) In the oil temperature detecting device according to any one of (1) to (3), the temperature of the outside air that has passed through the radiator is used as the outside temperature. Thus, the oil temperature can be accurately estimated even when the air heated by the radiator hits the oil pan.
[0091]
(5) In the oil temperature detection device according to any one of (1) to (4), the vehicle speed is corrected according to an operation state of the radiator fan. This makes it possible to accurately estimate the oil temperature even when the wind of the radiator fan hits the oil pan.
[0092]
(6) The control device for the internal combustion engine controls the internal combustion engine using the oil temperature calculated by the oil temperature detection device according to any one of the above (1) to (5). Thus, irrespective of the engine operation history and the history of environmental change, it is possible to prevent erroneous diagnosis of the fuel system diagnosis using the oil temperature TO.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a schematic configuration of a control device for an internal combustion engine according to an embodiment of the present invention.
FIG. 2 is a flowchart showing a control flow of the oil temperature detection device according to the present invention.
FIG. 3 is an explanatory diagram showing a characteristic example of a TTWS calculation table.
FIG. 4 is an explanatory diagram showing a characteristic example of a TTCT calculation table.
FIG. 5 is an explanatory diagram showing a characteristic example of a TTCN calculation table.
FIG. 6 is an explanatory diagram showing a characteristic example of a TTAVSP calculation table.
FIG. 7 is an explanatory diagram showing a characteristic example of a KOL calculation table.
FIG. 8 is a timing chart showing a correlation among Tw, TO, TTW, TTC, and TTA.
FIG. 9 is a flowchart showing a control for predicting an estimated oil surrounding temperature Tao.
FIG. 10 is a flowchart showing a control for predicting a radiator temperature TL.
FIG. 11 is an explanatory diagram showing a characteristic example of a TLGH calculation table.
FIG. 12 is an explanatory diagram showing a characteristic example of a KVSP calculation table.
FIG. 13 is a flowchart showing a control flow for calculating a VSOP instead of a VSP.
FIG. 14 is a flowchart showing a control flow for calculating an oil dilution fuel amount OF.
FIG. 15 is a flowchart showing a control flow of a first subroutine of FIG. 14;
FIG. 16 is an explanatory diagram showing a characteristic example of a MOFD map.
FIG. 17 is an explanatory diagram illustrating a characteristic example of a load correction table.
FIG. 18 is a flowchart showing a control flow of a second subroutine in FIG. 14;
FIG. 19 is an explanatory diagram showing a characteristic example of a MOFU map.
FIG. 20 is a flowchart showing a control flow for calculating an actual fuel injection pulse width TI.
FIG. 21 is a flowchart showing a flow of control of alcohol concentration estimation.
FIG. 22 is an explanatory diagram showing a characteristic example of an alcohol concentration calculation table.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Engine body 2 ... Combustion chamber 3 ... Intake valve 4 ... Intake passage 5 ... Exhaust valve 6 ... Exhaust passage 7 ... Air cleaner 8 ... Air flow meter 9 ... Throttle valve 11 ... Fuel injection valve 12 ... Engine control unit (ECU)
13 ... Oxygen concentration sensor 14 ... Three way catalyst 15 ... Water temperature sensor 16 ... Crank angle sensor 17 ... Outside air temperature sensor 18 ... Oil level sensor 19 ... Vehicle speed sensor

Claims (6)

A heat radiation correction value calculating unit that calculates a heat radiation correction value serving as a heat radiation component from the engine oil to the outside air using at least one of the outside air temperature and the vehicle speed,
An oil temperature detecting device for estimating an engine oil temperature using the heat radiation correction value. A heat reception correction value calculation unit that calculates a heat reception correction value that is a heat reception component to engine oil with the combustion of the internal combustion engine using a signal related to the engine load,
The oil temperature detection device according to claim 1, wherein the engine oil temperature is estimated using the heat reception correction value and the heat radiation correction value. 3. The oil temperature detecting device according to claim 1, wherein the estimated engine oil temperature is corrected according to an engine oil oil amount in the oil pan. The oil temperature detecting device according to any one of claims 1 to 3, wherein the temperature of the outside air that has passed through the radiator is used as the outside air temperature. The oil temperature detecting device according to any one of claims 1 to 4, wherein the vehicle speed is corrected according to an operation state of the radiator fan. An internal combustion engine control device that controls the internal combustion engine using the engine oil temperature calculated by the oil temperature detection device according to claim 1.

Images