JP3891064B2 - Control device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for an internal combustion engine.
[0002]
[Prior art]
As described in Japanese Patent Application Laid-Open No. 2001-98941, there is provided a heat retaining container for storing cooling water heated in the internal combustion engine, and the warm water stored in the heat retaining container is used during cold start of the internal combustion engine. A cooling / warming-up device for an internal combustion engine that is circulated in a cooling water passage of the internal combustion engine is known. In such a cooling / warming-up device, the internal combustion engine can be warmed up early by releasing the heat of the cooling water stored in the heat retaining container to the internal combustion engine when the internal combustion engine is cold-started.
[0003]
[Problems to be solved by the invention]
By the way, in recent internal combustion engines, control parameters (for example, fuel injection amount, fuel injection timing, fuel pressure, intake valve opening timing, throttle valve opening, fuel ignition timing) of the internal combustion engine are set based on the operating parameters of the internal combustion engine. The internal combustion engine is operated in an optimum state. One such operating parameter is the water temperature, which is the temperature of the cooling water that circulates in the cooling passage (engine passage) of the internal combustion engine. In a normal internal combustion engine, it is determined whether the internal combustion engine is warmed up from the water temperature. That is, if the water temperature is relatively high, the internal combustion engine body is warmed up. On the other hand, if the water temperature is relatively low, the internal combustion engine body is not warmed up.
[0004]
However, in the cooling / warming-up device described in the above publication, the temperature of the working oil of the internal combustion engine is low at the start of the internal combustion engine, or the catalyst temperature of the exhaust purification device of the internal combustion engine is lower than the activation temperature. However, only the cooling water temperature may be high. In this case, it is determined that the oil temperature of the hydraulic oil and the catalyst temperature of the exhaust purification device are also high. For this reason, the control parameters set based on the operating parameters including the water temperature are not optimal values for the operation of the internal combustion engine, and the starting failure due to large friction and the emission due to the catalyst not being activated. Will worsen.
[0005]
Accordingly, an object of the present invention is to provide a control device for an internal combustion engine that prevents the start failure of the internal combustion engine and the deterioration of the emission by setting optimal control parameters for the operation of the internal combustion engine when the internal combustion engine is started. It is to provide.
[0006]
[Means for Solving the Problems]
  In order to solve the above-described problem, in the first invention, a control device for an internal combustion engine is configured to set control parameters for the internal combustion engine in accordance with the temperature of the cooling medium, and stores heat when the internal combustion engine is stopped. In a control device equipped with a heat accumulator capable of increasing the temperature of the cooling medium by heat stored in the heat accumulator at least by the time of engine start, in a predetermined period after engine startBefore the temperature rises due to the heat stored in the regeneratorThe temperature of the cooling medium and the actual temperature of the cooling mediumDifferenceVarious control parameters of the internal combustion engine are set based on the above.
  Note that the term “until the engine is started” includes a case where the engine of the internal combustion engine is started at the same time. Further, the predetermined period may be a fixed time. For example, the control is calculated based on the temperature of the cooling medium before the preliminary temperature increase and the actual temperature of the cooling medium after the preliminary temperature increase. It may be a period until the value of the parameter becomes the same as the value of the control parameter calculated based on the actual temperature of the cooling medium.
[0007]
  In a second invention, in the first invention, the control parameter is at least one of a fuel injection timing, a fuel ignition timing, a fuel injection amount, an intake valve opening timing, a fuel pressure, and a throttle valve opening.
[0008]
  In the third invention, in the first invention, the fuel injection amount is decreased as the difference between the temperature of the cooling medium before the temperature rise and the actual temperature increases.
  According to a fourth aspect, in the first aspect, the fuel injection timing is advanced as the difference between the temperature of the cooling medium before the temperature rise and the actual temperature increases.
  In the fifth invention, in the first invention, the fuel pressure is increased as the difference between the temperature of the cooling medium before the temperature rise and the actual temperature increases.
  According to a sixth aspect, in the first aspect, the valve opening timing of the intake valve is retarded as the difference between the temperature of the cooling medium before the temperature rise and the actual temperature increases.
  In a seventh aspect, in the first aspect, the throttle valve opening is increased as the difference between the temperature of the cooling medium before the temperature rise and the actual temperature increases..
  In the eighth invention, in the first invention, the ignition timing is retarded as the difference between the temperature of the cooling medium before the temperature rise and the actual temperature increases..
[0009]
  First9According to the invention, in the first invention, the heat accumulator is a heat retaining device for the cooling medium, and heat is stored by retaining the temperature of the cooling medium.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to the drawings. FIG. 1 shows an internal combustion engine control apparatus according to a first embodiment of the present invention.
[0011]
The control device of the first embodiment controls the operation of the internal combustion engine by setting various control parameters to various values. Examples of such control parameters include the amount of fuel injected from the fuel injection valve into the fuel chamber (fuel injection amount), the timing at which fuel is injected from the fuel injection valve (fuel injection timing), and the fuel injection valve. Examples include the pressure applied (fuel pressure) and the opening of the throttle valve (throttle valve opening) for adjusting the flow rate of the intake gas flowing into the combustion chamber of the internal combustion engine. Furthermore, in an internal combustion engine in which the fuel in the combustion chamber of the internal combustion engine is ignited by a spark plug, a timing for igniting the fuel (fuel ignition timing) is given as a control parameter, and a variable valve mechanism is provided. In the internal combustion engine that is used, the opening timing and the opening amount of the intake valve or the exhaust valve are also mentioned as control parameters.
[0012]
These control parameters are determined based on various operating parameters so that the operating state of the internal combustion engine is optimized for the various operating parameters. That is, an operation parameter of the internal combustion engine is detected, and an optimal control parameter is set for the operation parameter so that the operation state of the internal combustion engine is optimized. Such operating parameters include, for example, the temperature of a cooling medium (cooling water) for cooling the internal combustion engine, the oil temperature of the working oil of the internal combustion engine, the catalyst temperature in the exhaust purification device, the load applied to the internal combustion engine, the internal combustion engine The number of rotations and the like. The exhaust gas purification device is an exhaust gas purification device that can effectively purify exhaust gas when the catalyst temperature becomes equal to or higher than the activation temperature.
[0013]
Actually, in the control device 1 of the first embodiment of the present invention, as shown in FIG. 1, signals are transmitted from various sensors 11 to 13 for detecting operation parameters to an electronic control unit (ECU) 10. The transmitted signal is processed in the electronic control unit 10 to determine various control parameter values. More specifically, the temperature sensor 11, the load sensor 12, the crank angle sensor 13, and the like detect the temperature of the cooling medium, the load applied to the internal combustion engine, and the catalyst temperature, and the detected values are transmitted to the electronic control unit 10. The electronic control unit 10 calculates a fuel injection timing, a fuel injection amount, a fuel pressure, a fuel ignition timing, a valve opening timing of the intake valve, and the like that optimize the operation state of the internal combustion engine from these operating parameters, and calculates the calculated values. Is transmitted to the fuel injection valve (or the fuel injection device including the fuel supplier) 14, the spark plug 15, the variable valve mechanism 16, the throttle valve 17, and the like. As a result, the internal combustion engine is always operated in an optimal operating state with respect to the operating parameters. In the first embodiment of the control device of the present invention, the oil temperature of the hydraulic oil and the catalyst temperature in the exhaust purification device are calculated from the temperature of the cooling medium.
[0014]
Incidentally, in the first embodiment of the present invention, the internal combustion engine has a cooling / warming-up mechanism 20 as shown in FIG. In FIG. 2, reference numeral 21 denotes an internal combustion engine body, and 22 denotes a heat radiating means such as a radiator. The internal combustion engine body 21 is provided with an engine internal flow path 23 through which a cooling medium (cooling water) for cooling the internal combustion engine main body 21 flows. This internal flow path 23 is formed around the combustion chamber 24 and the like. Through the area to be cooled. The engine internal channel 23 communicates with the radiator 22 via the upstream channel 25 and the downstream channel 26, and the cooling medium travels between the engine channel 23 and the radiator 22 via these channels 25, 26. . A water pump 27 is mounted in the engine flow path 23 in the vicinity of a connection point between the engine flow path 23 and the downstream flow path 26, and the cooling medium is supplied to the engine flow path 23 and the upstream side by the force of the water pump 27. The flow path 25, the radiator 22, and the downstream flow path 26 are circulated. Further, a thermo stud 28 is attached to a connection point between the engine internal flow path 23 and the upstream flow path 25, and the thermo stud 28 controls the flow of the cooling medium to the radiator 22. The temperature sensor 11 is attached to the in-engine flow path 23. The temperature in the engine flow path 23 detected by the temperature sensor 11 is transmitted to the electronic control unit 10. In the following description, the engine internal flow path 23, the upstream flow path 25, the radiator 22, and the downstream flow path 26 through which the cooling medium circulates are referred to as a cooling system.
[0015]
Further, in the cooling / warming-up mechanism 20 for the internal combustion engine, a heat retaining container (heat accumulator) 30 is provided. The heat insulating container 30 has a heat insulating layer 31 around it. The heat retaining container 30 is provided with one inlet and one outlet, and the container upstream flow path 32 is fluidly connected to the inlet of the heat retaining container 30. The container upstream flow path 32 is connected to the engine internal flow path 23 of the internal combustion engine body 21 in the vicinity of the upstream flow path 25. Further, a container downstream flow path 33 is fluidly connected to the outlet of the heat retaining container 30. The container downstream flow path 33 is fluidly connected to the engine internal flow path 23 near the downstream flow path 26 and closer to the internal combustion engine than the water pump 27. In addition, a fluid pump 34 is interposed in the container downstream flow path 33. The fluid pump 34 is connected to the electronic control unit 10. The fluid pump 34 is driven in accordance with a signal transmitted from the electronic control unit 10 after the electronic control unit 10 receives signals from the various sensors 11 to 13 and processing is performed in the electronic control unit 10 thereafter. When the fluid pump 34 is driven, it sends the cooling medium in the heat retaining container 30 to the engine internal flow path 23 and pushes the cooling medium in the engine internal flow path 23 of the internal combustion engine body 21 into the heat retaining container 30.
[0016]
In the internal combustion engine cooling / warming-up mechanism 20 configured as described above, the fluid pump 34 is operated during normal operation of the internal combustion engine (that is, during operation other than the warm-up operation of the internal combustion engine). A hot cooling medium is allowed to flow into the tank. Thus, during the normal operation of the internal combustion engine, the high-temperature cooling medium is stored in the heat retaining container 30, and the fluid pump 34 is stopped. Thereafter, when the operation of the internal combustion engine is stopped, the temperature of the cooling medium in the cooling systems 22, 23, 25, and 26 decreases to a temperature that is substantially the same as the outside air temperature. On the other hand, the temperature of the cooling medium accommodated in the heat retaining container 30 hardly decreases even after the internal combustion engine is stopped by the heat insulating layer 31. Therefore, the cooling medium accommodated in the heat retaining container 30 is maintained at a high temperature. That is, heat is stored in the heat retaining container 30.
[0017]
When the operation of the internal combustion engine is started again, the fluid pump 34 is operated until the engine is started, that is, before the engine is started or simultaneously with the engine is started. All the cooling medium is caused to flow into the engine flow path 23 of the internal combustion engine body 24. On the other hand, the cooling medium in the engine flow path 23 of the internal combustion engine body 21 is pushed into the heat retaining container 30. That is, the temperature of the cooling medium in the engine internal passage 23 is raised by the heat stored in the heat retaining container 30 (the cooling medium is preliminarily heated), and the temperature of the cooling medium flowing in the internal passage 23 is The internal combustion engine body 21 is warmed up due to a relatively high temperature. Thus, for example, the fuel injection valve 14 and the combustion chamber 24 are warmed. Thus, if the internal combustion engine body 21 is warmed up before the engine is started, fuel vaporization is promoted immediately after the engine is started, for example. Therefore, in such an internal combustion engine, the combustion state of the fuel in the combustion chamber 24 of the internal combustion engine is relatively good immediately after the engine is started, and as a result, the fuel consumption immediately after the engine is started and the exhaust emission is improved. be able to.
[0018]
By the way, when the internal combustion engine having such a cooling / warming-up mechanism 20 is controlled by the control device 1 as described above, the temperature of the cooling medium, which is one of the operating parameters, is a temperature sensor disposed in the engine flow path. 11 is detected. As described above, in the cooling / warming-up mechanism 20, the temperature of the cooling medium flowing in the engine flow path 23 is relatively high before the engine is started, and therefore the temperature of the cooling medium detected from the temperature sensor 11 is relatively high. It is hot. On the other hand, even when the temperature of the cooling medium in the engine internal flow path becomes relatively high, the oil temperature of the working oil of the internal combustion engine and the catalyst temperature in the exhaust purification device have not risen, and are substantially the same as the outside air temperature. It has become.
[0019]
However, as described above, in the control device, the oil temperature of the working oil and the catalyst temperature in the exhaust purification device are calculated from the temperature of the cooling medium, so the actual oil temperature of the working oil and the catalyst temperature of the exhaust purification device become high. Even if not, for example, if the cooling medium is preliminarily heated and the temperature of the cooling medium is high, it is calculated that the oil temperature and the catalyst temperature are high. As described above, if the oil temperature of the hydraulic oil and the catalyst temperature of the exhaust purification device are calculated to be higher than the actual temperature, the values of various control parameters set based on the high calculated values are the values of the operation of the internal combustion engine. The value of the control parameter for optimizing the engine becomes a different value, and the internal combustion engine cannot be operated in an optimal operating state. More specifically, if the oil temperature of the hydraulic oil is calculated to be higher than the actual temperature, the friction in the internal combustion engine will be greater than expected, resulting in a starting failure. Further, if the catalyst temperature of the exhaust purification device is calculated to be higher than the actual temperature, it is determined that the catalyst is activated even though it is not activated, thereby leading to deterioration of exhaust emission.
[0020]
On the other hand, according to the control device 1 of the first embodiment of the present invention, the fluid pump 34 is operated before the engine is started during the predetermined period after the engine is started, Various control parameters of the internal combustion engine based on the temperature of the cooling medium before raising the temperature of the cooling medium (the temperature of the cooling medium before the preliminary heating) and the actual temperature of the cooling medium (after the preliminary heating) Is set. More specifically, the temperature of the cooling medium before the preliminary temperature rise is detected by the temperature sensor 11 until the engine is started, and the detected value is stored in the electronic control unit 10. Next, the fluid pump 34 is operated until the engine is started, and the temperature of the cooling medium in the engine flow path 23 is increased. In a predetermined period after the engine is started, the actual temperature of the cooling medium in the engine internal passage 23 is detected always or immediately after the engine is started. Then, the internal combustion engine is operated so as to be most suitable for the temperature of the cooling medium and other operating parameters by the stored temperature of the cooling medium before the temperature rise, the actual temperature of the cooling medium, and other operating parameters. Thus, various control parameters of the internal combustion engine are set. After the predetermined period after the engine is started, various control parameters of the internal combustion engine are set according to the actual temperature of the cooling medium and other operating parameters.
[0021]
Here, the temperature of the cooling medium before the preliminary temperature rise is substantially the same as the outside air temperature, that is, substantially the same as the oil temperature of the working oil of the internal combustion engine and the catalyst temperature of the exhaust purification device. The oil temperature and catalyst temperature of these hydraulic oils do not change until the internal combustion engine is started even if the temperature of the cooling medium in the engine internal passage 23 is increased. That is, the temperature of the cooling medium before the preliminary temperature increase is the same as the oil temperature and the catalyst temperature of the hydraulic oil after the preliminary temperature increase of the cooling medium.
[0022]
For this reason, the oil temperature and catalyst temperature of the hydraulic oil can be calculated by detecting the temperature of the cooling medium before the preliminary temperature increase, so the temperature of the cooling medium before the preliminary temperature increase and the actual temperature of the cooling medium can be calculated. By detecting the temperature, it is possible to estimate the oil temperature of the hydraulic oil and the catalyst temperature of the exhaust purification device only by detecting the temperature of the cooling medium. Then, by being able to estimate and detect the oil temperature and catalyst temperature of these hydraulic oils and the actual temperature of the cooling medium, the control parameters of the internal combustion engine are best suited to these oil temperature, catalyst temperature, and cooling medium temperature. Is set, and the internal combustion engine is operated optimally. For this reason, the friction of the internal combustion engine does not become larger than expected, and a starting failure is prevented. Further, it is not determined that the catalyst is activated even though it is not activated, so that the exhaust emission is prevented from deteriorating.
[0023]
In the first embodiment, the temperature of the cooling medium is increased by the heat stored in the heat retaining container 30 until the engine is started. The relationship with the start timing of the internal combustion engine can be divided into the following two. As a first relationship, there is a case where the preliminary temperature rise of the cooling medium is started before the internal combustion engine is started. In this case, since the internal combustion engine is started after the temperature of the cooling medium in the engine internal passage 23 is completely raised, the improvement in exhaust emission and fuel consumption can be maximized. Further, as a second relationship, there is a case where the preliminary temperature rise of the cooling medium is started simultaneously with the start of the internal combustion engine. When the cooling medium is discharged into the engine internal flow path 23 simultaneously with the start of the internal combustion engine in this way, it is very easy to control because the inflow of the cooling medium and the start of the internal combustion engine are simultaneous. However, when the preheating of the cooling medium is started before the internal combustion engine is started as in the first relationship, the heat stored in the heat retaining container 30 when the internal combustion engine is started is stored in the engine internal flow path 23. There is also a case where the cooling medium is hardly discharged into the cooling medium, that is, the cooling medium stored in the heat retaining container 30 hardly flows into the engine internal flow path 23. For this reason, the cooling medium after the preliminary temperature increase means either after the start of the preliminary temperature increase or after the completion of the preliminary temperature increase.
[0024]
In the first embodiment, various parameters of the internal combustion engine are set based on the temperature of the cooling medium before the preliminary temperature increase and the actual temperature of the cooling medium in a predetermined period after the engine is started. However, the predetermined period is a period until, for example, the oil temperature and the catalyst temperature estimated from the actual cooling medium temperature after the engine start become substantially the same as the actual oil temperature and the catalyst temperature. Alternatively, the predetermined period may be a fixed time, or may be a period until the cooling medium reaches a predetermined temperature, and the engine internal flow path 23 in the first relationship. When the cooling medium is discharged, the time may be calculated based on the temperature difference between the temperature of the cooling medium before the preliminary temperature increase and the temperature of the cooling medium at the time of starting the engine.
[0025]
In addition, setting various control parameters of the internal combustion engine based on the temperature of the cooling medium before the preliminary temperature increase and the actual temperature of the cooling medium after the preliminary temperature increase is particularly effective when the internal combustion engine is cold started. Is. This is because if the preliminary temperature increase is performed at the time of cold start, the temperature of the cooling medium before the preliminary temperature increase and the temperature of the cooling medium after the preliminary temperature increase are greatly different. Conversely, when the temperature of the cooling medium in the engine flow path 23 is relatively high before the preliminary temperature increase, that is, when the internal combustion engine has been warmed up before the engine is started, the preliminary temperature increase is performed. Alternatively, it is possible to preliminarily raise the temperature and set various control parameters based only on the temperature of the cooling medium after the preliminary temperature rise.
[0026]
Next, the control in the control apparatus 1 of 2nd embodiment of this invention is demonstrated. The control device of the second embodiment is a control device similar to the control device of the first embodiment.
[0027]
First, the operation of the internal combustion engine is stopped in a state where a high-temperature cooling medium is stored in the heat retaining container 30. For example, when a door of a vehicle equipped with the control device of the present invention is opened, a user is seated in a driver's seat, or a key is inserted, a door switch, a seating sensor, and a key sensor (not shown) are detected. Or the like) is transmitted to the electronic control unit 10. When such a signal is transmitted to the electronic control unit 10, the temperature Tw1 of the cooling medium before the preliminary temperature increase in the engine internal flow path 23 of the internal combustion engine is detected. Immediately after this, the high-temperature cooling medium stored in the heat retaining container 30 is caused to flow into the engine internal flow path 23. However, when the operation of the internal combustion engine is stopped, the high-temperature cooling medium is not sufficiently stored in the heat insulation container, or the temperature drops due to the passage of a considerable time after the internal combustion engine is stopped. If the cooling medium stored in the tank becomes relatively low in temperature, the preliminary temperature rise is not performed.
[0028]
When the preliminary temperature increase is performed, the temperature of the cooling medium in the engine internal flow path 23 increases. When the preliminary temperature increase is completed, that is, when almost all of the cooling medium stored in the heat retaining container 30 flows into the engine internal flow path 23, the engine internal flow path 23 is gradually increased until the internal combustion engine is started. The temperature of the cooling medium inside decreases. Then, the temperature Tw2 of the cooling medium in the engine internal passage 23 is detected when the internal combustion engine is started. Then, a temperature difference ΔT between the temperature Tw1 of the cooling medium before the preliminary temperature increase and the temperature Tw2 of the cooling medium after the preliminary temperature increase is calculated as ΔT = Tw2−Tw1.
[0029]
Next, a control parameter of the internal combustion engine is calculated from the detected value Tw1 and the temperature difference ΔT. First, reference values of various control parameters are calculated from the temperature Tw1 of the cooling medium after the preliminary temperature increase and other operating parameters. Next, correction values of various control parameters are calculated from the temperature difference ΔT, and are added or subtracted to the reference value of the control parameters to determine the values of the various control parameters. In this case, the relationship between the temperature difference ΔT and the correction values of various control parameters is experimentally calculated in advance as shown in FIG. 3 and stored in the electronic control unit 10 as a map. The internal combustion engine is operated with the value of the control parameter thus determined, whereby the internal combustion engine is operated in an optimum state with respect to various operation parameters.
[0030]
Next, the relationship between the temperature difference ΔT of the cooling medium before and after the preliminary temperature increase and the correction value will be described with reference to FIG. 3A shows the relationship between the temperature difference ΔT and the correction value of the fuel injection amount Q, FIG. 3B shows the relationship between the temperature difference ΔT and the correction value of the fuel injection timing Tin, and FIG. FIG. 3D shows the relationship between the temperature difference ΔT and the correction value of the fuel pressure P, FIG. 3D shows the relationship between the temperature difference ΔT and the correction value of the valve opening timing To, and FIG. 3E shows the temperature difference ΔT and the throttle valve opening Dt. FIG. 3F shows the relationship between the temperature difference ΔT and the correction value of the fuel ignition timing Tig.
[0031]
As shown in FIG. 3A, when the temperature difference ΔT increases, the fuel injection amount Q is decreased. A large temperature difference ΔT means that the wall temperature around the combustion chamber 24 is high, and this makes it difficult for fuel to adhere to the wall around the combustion chamber 24. For this reason, the fuel to inject can be reduced and, thereby, fuel consumption improves.
[0032]
Further, as shown in FIG. 3B, when the temperature difference ΔT increases, the fuel injection timing Tin is advanced. As described above, when the temperature difference ΔT increases, the fuel injection amount Q is decreased. Therefore, even if fuel is injected after the fuel injection timing Tin is advanced and the piston reaches near the top dead center, Fuel is less likely to adhere to the surrounding walls. Thus, the fuel and air are easily mixed by advancing the fuel injection timing Tin.
[0033]
As shown in FIG. 3C, the fuel pressure P is increased as the temperature difference ΔT increases. When the fuel pressure P is increased, the fuel can be atomized to improve the combustion state in the combustion chamber 24, but on the other hand, the fuel flies far and adheres to the wall surface around the combustion chamber 24. It becomes easy. On the other hand, when the temperature difference ΔT increases, the fuel is likely to evaporate, and thus the fuel is less likely to adhere to the wall surface around the combustion chamber 24.
[0034]
Further, as shown in FIG. 3D, the opening timing To of the intake valve is retarded as the temperature difference ΔT increases. When the intake valve opening timing To is advanced, a large amount of high-temperature EGR gas (exhaust gas once combusted in the combustion chamber) flows into the combustion chamber 24, and the wall surface around the combustion chamber 24 is heated. On the other hand, the output torque of the internal combustion engine becomes small. On the other hand, when the temperature difference ΔT increases, it is not necessary to raise the temperature of the wall surface around the combustion chamber 24, so the opening timing To of the intake valve is retarded and the flow rate of EGR gas flowing into the combustion chamber 24 is reduced. Can be made. As a result, the output torque of the internal combustion engine can be increased, so that the friction due to the oil temperature not rising can be overcome.
[0035]
Further, as shown in FIG. 3E, the throttle valve opening Dt is increased as the temperature difference ΔT increases. As described above, when ΔT is large, the temperature of the cooling medium is increased, but the temperature of the hydraulic oil is not increased, so that the friction is increased. On the other hand, by increasing the throttle valve opening Dt, the output torque of the internal combustion engine is increased, so that the friction can be overcome.
[0036]
As shown in FIG. 3F, the fuel ignition timing Tig is retarded as the temperature difference ΔT increases. In general, when the internal combustion engine is started in a state where the temperature of the cooling medium has not been raised, the fuel ignition timing Tig is retarded in order to increase the catalyst temperature of the exhaust emission control device. However, in the cooling / warming-up mechanism 20 as described above, since the temperature of the cooling medium is raised, it is determined that the catalyst temperature is high, and the fuel ignition timing Tig is not retarded. Therefore, in the control device of the present invention, the fuel ignition timing Tig is retarded, and thereby the catalyst temperature of the exhaust purification device is raised.
[0037]
Next, control parameter calculation control in the control device of the second embodiment will be described with reference to FIG. First, in step 101, it is determined whether or not it is a preliminary temperature increase timing, that is, whether or not a signal is transmitted from a door sensor, a seating sensor, a key sensor, or the like. If it is determined that it is not the preliminary temperature increase timing, that is, if signals are not transmitted from various sensors, step 101 is repeated. On the other hand, if it is determined in step 101 that the preliminary temperature increase timing is reached, the process proceeds to step 102. In step 102, the temperature sensor 11 detects the temperature Tw1 of the cooling medium in the engine flow path 23 before the preliminary temperature increase. Next, in step 103, it is determined whether or not preliminary temperature increase is executed, that is, for example, whether or not the temperature of the cooling medium in the heat retaining container 30 remains high. If it is determined in step 103 that the preliminary temperature increase is not performed, the process proceeds to step 104. In step 104, the temperature Tw2 of the cooling medium in the engine internal passage 23 after the preliminary temperature rise is detected. In step 105, the values of various control parameters are calculated from the coolant temperature Tw2 detected in step 104 and other operating parameters, and the control parameter calculation control is terminated.
[0038]
  On the other hand, if it is determined in step 103 that the preliminary temperature increase is to be executed, the routine proceeds to step 106. In step 106, the fluid pump 34 is operated to perform preliminary temperature rise. Next, at step 107, the temperature Tw2 of the cooling medium in the engine internal passage 23 after the preliminary temperature increase is detected, and the temperature Tw1 of the cooling medium before the preliminary temperature increase is determined from the temperature Tw2 of the cooling medium after the preliminary temperature increase. The subtracted value is calculated as ΔT. Next, at step 108, it is determined whether or not the temperature difference ΔT is larger than a predetermined value a (a relatively small value, a value near zero), and the temperature difference ΔT is larger than the predetermined value a.smallIf it is determined, the process proceeds to step 105. In step 108, the temperature difference ΔT is a predetermined value a.more thanIf it is determined, the process proceeds to step 109. In step 109, reference values of various control parameters are calculated from the temperature Tw1 and operating parameters other than the temperature of the cooling medium, while correction values of various control parameters as shown in FIG. 3 are calculated from the temperature difference ΔT. A value obtained by adding or subtracting the correction value to the reference value is calculated as the value of the control parameter. Next, at step 110, it is determined whether or not the internal combustion engine has been started. If it is determined that the internal combustion engine has not been started, the routine returns to step 107. On the other hand, if it is determined in step 110 that the internal combustion engine has been started, the control parameter calculation control is terminated.
[0039]
In the second embodiment, correction values for various control parameters for the temperature difference ΔT are obtained in advance and stored in the electronic control unit as a two-dimensional map. Then, the control parameter reference value is calculated from the coolant temperature Tw1, and the control parameter value is calculated by adding or subtracting the temperature difference ΔT and the control parameter correction value obtained from the map. However, the value of the control parameter may be obtained by another method. For example, the values of various control parameters for the temperature Tw1 of the cooling medium before the preliminary temperature increase and the temperature Tw2 of the cooling medium after the preliminary temperature increase are obtained in advance and stored in the electronic control unit as a three-dimensional map. Then, the value of the control parameter may be obtained from the temperature Tw1, the temperature Tw2, and the map.
[0040]
In the above embodiment, only the fuel injection amount, the fuel injection timing, the fuel pressure, the intake valve opening timing, the throttle valve opening, and the fuel ignition timing are listed as control parameters. Other control parameters such as quantity are also conceivable. Furthermore, in the above embodiment, the operating parameters include the temperature of the cooling medium, the temperature of the hydraulic oil, the catalyst temperature of the exhaust gas purification device, the load applied to the internal combustion engine, and the rotational speed of the internal combustion engine, but the intake air flowing into the internal combustion engine Other operating parameters such as gas temperature and oxygen concentration in the exhaust gas are also conceivable.
[0041]
Furthermore, in the above-described embodiment, the case where the oil temperature of the hydraulic oil and the catalyst temperature of the exhaust gas purification device are estimated from the temperature of the cooling medium has been described as an example, but other values may be estimated. Good. Alternatively, when there are two different internal engine flow paths in the internal combustion engine, the temperature of the cooling medium in the engine internal flow path of another system is different from the temperature of the cooling medium in the internal flow path of one system. The controller of the present invention can be used even in the case where the estimation is made.
[0042]
【The invention's effect】
According to the first invention, when the engine is started, the control parameter of the internal combustion engine is set to an optimum value for the operation of the internal combustion engine in consideration of the oil temperature of the internal combustion engine and the temperature of the exhaust purification catalyst. Start-up failures and emission deterioration are prevented.
[Brief description of the drawings]
FIG. 1 is a schematic view of a control device of the present invention.
FIG. 2 is a schematic view of a cooling / warming-up mechanism for an internal combustion engine.
FIG. 3 is a diagram illustrating correction values of various control parameters with respect to a temperature difference.
FIG. 4 is a flowchart of control parameter calculation control.
[Explanation of symbols]
1 ... Control device
10 ... Electronic control unit
11 ... Water temperature sensor
20 ... Cooling / warming mechanism
24 ... Combustion chamber
30 ... Thermal insulation container (heat accumulator)

Claims (9)

A control device for an internal combustion engine configured to set a control parameter for the internal combustion engine in accordance with the temperature of the cooling medium,
In a control device comprising a heat accumulator capable of storing heat when the internal combustion engine is stopped, and increasing the temperature of the cooling medium by the heat stored in the heat accumulator at least until the engine is started,
Various control parameters of the internal combustion engine are set based on the difference between the temperature of the cooling medium before the temperature rises due to the heat stored in the heat accumulator during the predetermined period after the engine is started and the actual temperature of the cooling medium A control device designed to do this.   2. The control device for an internal combustion engine according to claim 1, wherein the control parameter is at least one of a fuel injection timing, a fuel ignition timing, a fuel injection amount, an intake valve opening timing, a fuel pressure, and a throttle valve opening. 2. The control device according to claim 1, wherein the fuel injection amount is decreased as the difference between the temperature of the cooling medium before the temperature rise and the actual temperature increases . 2. The control device according to claim 1, wherein the fuel injection timing is advanced as the difference between the temperature of the coolant before the temperature rise and the actual temperature increases . The control device according to claim 1, wherein the fuel pressure is increased as the difference between the temperature of the cooling medium before the temperature rise and the actual temperature increases . 2. The control device according to claim 1, wherein the opening timing of the intake valve is retarded as the difference between the temperature of the cooling medium before the temperature rise and the actual temperature increases . 2. The control device according to claim 1, wherein the throttle valve opening is increased as a difference between the temperature of the cooling medium before the temperature rise and the actual temperature increases . 2. The control device according to claim 1, wherein the ignition timing is retarded as the difference between the temperature of the cooling medium before the temperature rise and the actual temperature increases .   The control apparatus for an internal combustion engine according to claim 1, wherein the heat accumulator is a heat retaining container for a cooling medium, and heat is stored by retaining the temperature of the cooling medium.

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