JP2006125288A - Cooling control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve fuel economy of an internal combustion engine using fuel having different boiling points for different purposes. <P>SOLUTION: This cooling device for the internal combustion engine 11 is provided with a water temperature control means 13 controlling the temperature of cooling water cooling the internal combustion engine 11 to target cooling water temperature T<SB>T</SB>, and a target water temperature change means 41 changing the target cooling water temperature T<SB>T</SB>in accordance with an octane number of fuel supplied to the internal combustion engine 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cooling control device for an internal combustion engine.

Conventionally, a method of separating fuel such as gasoline into a fuel having a relatively low boiling point (low-boiling point fuel) and a fuel having a relatively high boiling point (high-boiling point fuel) and appropriately using them in accordance with the operating state of the engine is known. ing.
As an example of such a technique, there is a technique disclosed in Patent Document 1 below. In this technique, a fuel injection valve is provided in each of the engine intake port and the cylinder, and high-boiling point fuel is provided in the intake port. While supplying to a fuel injection valve, low boiling point fuel is supplied to the fuel injection valve provided in the cylinder.

With such a configuration, when starting the engine, low boiling point fuel injected from the fuel injection valve in the cylinder can be used to ensure ignitability, and high boiling point component fuel with low ignitability is generated by the heat of the intake port. It is described that combustion can be improved by atomization.
On the other hand, improvement of fuel efficiency has become an increasingly important issue in recent years from the viewpoint of global environmental protection and energy saving, but as one of the methods to improve engine fuel consumption, piston sliding resistance (so-called friction loss) is used. There are ways to reduce it. In this case, it is known to reduce the friction loss by reducing the oil viscosity.
JP 2004-27911 A

  However, if the temperature of the engine is raised, the friction loss can be reduced by reducing the oil viscosity, but if the temperature of the engine is raised excessively, the fuel will self-ignite. For this reason, for example, in an engine in which low-boiling point fuel and high-boiling point fuel can be used properly as in the technique of Patent Document 1 described above, the engine temperature is not such that low-boiling point fuel does not cause unexpected self-ignition. You are forced to set the engine coolant temperature. For this reason, the engine temperature must be maintained at a relatively low temperature even when using high-boiling point fuel, the oil viscosity cannot be suppressed, and fuel consumption performance deteriorates.

  The present invention has been devised in view of such problems, and an object of the present invention is to provide a cooling control device for an internal combustion engine that can improve the fuel consumption of an internal combustion engine that uses different fuels with different boiling points.

In order to achieve the above object, a cooling control apparatus for an internal combustion engine according to the present invention (Claim 1) includes a water temperature control means for controlling the temperature of cooling water for cooling the internal combustion engine to a target cooling water temperature, and the internal combustion engine. And a target water temperature changing means for changing the target cooling water temperature in accordance with the octane number of the fuel supplied to the engine.
The cooling control apparatus for an internal combustion engine of the present invention according to claim 2 is the content of claim 1, wherein the target water temperature changing means increases the target cooling water temperature as the octane number of the fuel increases. It is characterized by setting.

  According to a third aspect of the present invention, there is provided a cooling control apparatus for an internal combustion engine according to the first or second aspect, wherein the fuel fractionation means fractionates a part of the fuel into a low-octane fuel and a high-octane fuel. And when the internal combustion engine is started, the low-octane fuel fractionated by the fuel fractionation means is supplied to the internal combustion engine, and after the warm-up of the internal combustion engine is finished, the fractionated fuel by the fuel fractionation means And a fuel selection means for supplying high octane fuel to the internal combustion engine.

According to a fourth aspect of the present invention, there is provided the cooling control apparatus for an internal combustion engine according to the third aspect, wherein the fuel selection means has a remaining amount of high octane fuel fractionated by the fuel fractionation means. In the case where the amount is equal to or less than the fixed amount, the base fuel that is not fractionated is supplied to the internal combustion engine.
According to a fifth aspect of the present invention, there is provided a cooling control apparatus for an internal combustion engine according to the present invention, wherein the load detection means for detecting the load of the internal combustion engine and the ignition timing for changing the ignition timing of the internal combustion engine are provided. The ignition timing changing means detects that the high-octane fuel is supplied to the internal combustion engine by the fuel selection means and that the load of the internal combustion engine is high by the load detection means. If it is, the ignition timing is advanced.

According to the cooling control apparatus for an internal combustion engine of the present invention, it is possible to improve the fuel efficiency of an internal combustion engine that selectively uses fuels having different boiling points (that is, fuels having different octane numbers). (Claim 1)
Also, by setting the target temperature of the cooling water (target cooling water temperature) higher as the octane number of the fuel supplied to the internal combustion engine increases, the oil viscosity is reduced while avoiding self-ignition of the fuel, that is, knocking. It can reduce and can contribute to improvement in fuel consumption. (Claim 2)
In addition, when the internal combustion engine is started, the startability can be improved by using the low octane fuel, and after the warming up, the high temperature of the internal combustion engine can be increased and the oil viscosity can be reduced by using the high octane fuel. (Claim 3)
In addition, when the remaining amount of high-octane fuel falls below a predetermined amount, it is possible to use low-octane fuel or high-octane fuel by using the base fuel that is the fuel before being fractionated into low-octane fuel and high-octane fuel. Even when the octane fuel is insufficient, the internal combustion engine can be operated reliably. (Claim 4)
Further, when high octane fuel is supplied to the internal combustion engine and the load on the internal combustion engine is high, the output of the internal combustion engine can be improved by advancing the ignition timing of the internal combustion engine. (Claim 5)

The internal combustion engine cooling control apparatus according to the first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic block diagram showing the overall configuration of the internal combustion engine. FIG. Schematic graphs showing the relationship with the boiling point, FIGS. 3 and 4 are schematic flowcharts showing the operation.
As shown in FIG. 1, a vehicular gasoline engine (an internal combustion engine; hereinafter simply referred to as “engine”) 11 includes an intake port 52 that communicates with an intake manifold 51, an exhaust port 54 that communicates with an exhaust passage 53, and a combustion chamber 55. A spark plug 56, an intake valve 57, an exhaust valve 58, and an injector 59 for injecting fuel into the intake port 52 are provided.

Further, the intake manifold 51 is provided with an intake manifold pressure sensor 60 that measures the atmospheric pressure (so-called intake manifold pressure) in the intake manifold 51 and transmits a measurement result to the ECU 14 described later.
The engine 11 is water-cooled, and is provided with a radiator 12 for cooling the cooling water. An electronically controlled thermostat (water temperature control means; hereinafter simply referred to as “thermostat”) is provided between the radiator 12 and the engine 11. 13) is provided, and by adjusting the flow rate of the cooling water flowing between the radiator 12 and the engine 11, the cooling water is controlled to become the target water temperature (target cooling water temperature T _T ), The engine 11 can be prevented from overheating.

  In addition, the engine 11 includes low boiling point gasoline (low boiling point fuel) having a relatively low boiling point and high boiling point gasoline (high boiling point fuel) having a relatively high boiling point as the engine (gasoline) necessary for the operation. It can be used properly according to the driving situation. The boiling point of gasoline changes according to the octane number contained in the gasoline. For example, the boiling point of gasoline having a low octane number is low, and the boiling point of gasoline having a high octane number is high. Therefore, hereinafter, low boiling gasoline is referred to as “low octane gasoline” and high boiling gasoline is referred to as “high octane gasoline”. Gasoline before being fractionated into low-octane gasoline and high-octane gasoline is called base gasoline (base fuel).

  The vehicle also includes a first gasoline tank 16 that stores base gasoline, a second gasoline tank 17 that stores low-octane gasoline, and a third gasoline tank 18 that stores high-octane gasoline. To a gasoline fractionation device (fuel fractionation means) 15 for fractionating low-octane gasoline and high-octane gasoline.

The first gasoline tank 16, the second gasoline tank 17, and the third gasoline tank 18 are each provided with a fuel remaining amount sensor (not shown), and are stored in the first to third tanks 16, 17, and 18, respectively. The amount of gasoline is measured, and the measurement result can be transmitted to the ECU 14.
The first gasoline tank 16 has the largest capacity compared to the second gasoline tank 17 and the third gasoline tank 18, and the high-boiling gasoline tank 18 is built in the first gasoline tank 16.

Further, the second gasoline tank 17 and the third gasoline tank 18 are connected by a connection pipe line 19, and the connection pipe line 19 is provided with a fourth pump 20. Further, the end 19 a on the third gasoline tank 18 side in the connection pipe 19 is disposed so as to be located in the upper part in the third gasoline tank 18.
The high octane gasoline stored in the third gasoline tank 18 is generated by vaporizing a component having a low boiling point in the base gasoline, that is, low octane gasoline. Further, the low-octane gasoline that has been vaporized is sent to the low-boiling point gasoline tank 17 through the connection pipe 19 by the pump 20, so that the low-octane gasoline can be stored in the second gasoline tank 17.

  The third gasoline tank 18 and the first gasoline tank 16 can be communicated with each other through a connection valve (not shown), and the remaining amount of high octane gasoline stored in the third gasoline tank 18 is a predetermined amount. In the following, this connection valve is opened, and base gasoline is injected into the third gasoline tank 18 according to the storage amount of the first gasoline tank. The connection valve is controlled by an ECU 14 described later. In addition, you may make it branch from the 1st feed line 22 mentioned later, and may supply a fixed quantity of base gasoline to a 3rd gasoline tank.

  The gasoline tanks 16, 17, 18 of the gasoline fractionator 15 and the injector 59 of the engine 11 are connected by first to third feed lines 22, 23, 24, respectively. In addition, the first, second, and third feed pipelines 22, 23, and 24 discharge the base gasoline, the low-octane gasoline, and the high-octane gasoline from the first to third gasoline tanks 18 to the injector 59, respectively. To third fuel pumps 25, 26, 27.

The second and third feed lines 23 and 24 are provided with second and third regulator valves 29 and 30 for controlling the pressures P _R2 and P _R3 of gasoline supplied to the injector 59, respectively. . Further, return pipes 36 and 37 extend from the second and third regulator valves 29 and 30 to the second gasoline tank 17 and the third gasoline tank 18, and the pressure is increased by the second and third regulator valves 29 and 30. The surplus low octane number gasoline and high octane number gasoline generated by the restriction can be returned to the second gasoline tank 17 and the third gasoline tank 18, respectively.

Further, a first return pipe 34 extends from the injector 59 of the engine 11 to the first gasoline tank 16, so that surplus fuel when supplied to the injector 21 can be returned to the base fuel tank 16. It has become.
The regulator pressures of the first to third regulator valves 28, 29, and 30 are increased as the load on the engine 11, that is, the intake manifold pressure measured by the intake manifold pressure sensor 60 increases. The ECU 14 is controlled later. And the kind of gasoline supplied to injector 21 is chosen by changing each regulator pressure of these 1st-3rd regulator valves 28, 29, and 30 suitably. This gasoline selection will be described later.

Furthermore, the first to third one-way valves 31, 32, and 33 are respectively provided in the feed lines 22, 23, and 24, and the insides of the first to third feed lines 22, 23, and 24 are respectively provided. It is possible to prevent the gasoline from flowing back to the first to third gasoline tanks 16, 17 and 18.
The ECU 14 is an electronic control unit in which an input / output device, a memory, a CPU, a timer, etc. (all of which are not shown) are built, and as a software, a target water temperature changing unit (target water temperature changing means) 41 and a fuel selecting unit (Fuel selecting means) 42 is incorporated.

Among these, the target water temperature changing unit 41 sets the target when the octane number of gasoline supplied from the gasoline fractionator 15 to the engine 11 is high (that is, when high octane number gasoline is supplied to the injector 59 of the engine 11). the coolant temperature T _T is set to the second target water temperature T _T2, whereas, if the octane number of the gasoline to be supplied to the engine 11 is low (i.e., when low-octane gasoline is supplied to the injector 59 of the engine 11) or base When gasoline is supplied to the injector 59, the target cooling water temperature T _T is set to the first target water temperature T _T1 (where the first target water temperature T _T1 ≦ the second target water temperature T _T2 ). The first target water temperature T _T1 and the second target water temperature T _T2 are stored in advance in a memory (not shown) in the ECU 14.

The target water temperature changing unit T _T can perform feedback control for correcting the target cooling water temperature T _T based on the actual cooling water temperature T _W detected by a water temperature sensor (not shown) provided in the engine 11. It has become.
The fuel selector 42 controls the regulator pressures of the first to third regulator valves 28, 29, and 30 independently of each other. As a result, the fuel supplied to the injector 59 can be base gasoline, Either low-octane gasoline or high-octane gasoline can be selected.

For example, when only the base gasoline is supplied to the injector 59, the fuel selector 42 controls the second regulator valve 29 and the third regulator valve 30 so that the opening degrees of the second regulator valve 29 and the third regulator valve 30 are reduced, thereby the second regulator valve. The pressure of low octane gasoline supplied from 30 to the injector 59 (ie, the second regulator pressure) P _R2 and the pressure of high octane gasoline supplied from the third regulator valve 30 to the injector 59 (ie, the third regulator pressure) P _R3 is controlled to be smaller than the discharge pressure P _P1 of the first fuel pump 25 that is a fuel pump for base gasoline.

On the other hand, when only low-octane gasoline is supplied to the injector 59, the third regulator pressure P _R3 is controlled so that the opening degree of the third regulator valve becomes small, so that the third regulator pressure P _R3 becomes the discharge pressure P of the first fuel pump 25. The second regulator pressure P _R2 becomes larger than the discharge pressure P _P1 of the first fuel pump 25 by controlling so as to be smaller than _P1 and controlling the opening of the second regulator valve to be larger. To control.

On the other hand, when only high-octane gasoline is supplied to the injector 59, the third regulator pressure P _R3 is controlled to increase the opening of the third regulator valve 30 so that the third regulator pressure P _R3 is the discharge pressure P of the first fuel pump 25. The second regulator pressure P _R2 becomes smaller than the discharge pressure P _P1 of the first fuel pump 25 by controlling so as to be larger than _P1 and controlling the opening of the second regulator valve to be smaller. To control.

Since the internal combustion engine cooling control apparatus according to the first embodiment of the present invention is configured as described above, the following operations and effects are achieved.
First, as shown in step S11 of FIG. 3, the target water temperature changing unit 41 of the ECU 14 determines whether or not the actual temperature T _W of the cooling water detected by a water temperature sensor (not shown) is lower than a predetermined temperature T _S. Is done. Here, when it is determined that the actual cooling water temperature T _W is lower than the predetermined temperature T _S (Yes route of step S11), the third regulator pressure P _R3 is greater than the discharge pressure P _P1 of the first fuel pump 25. Of the ECU 14 so that the third regulator valve 30 is controlled by the fuel selector 42 of the ECU 14 and the second regulator pressure P _R2 is higher than the discharge pressure P _P1 of the first fuel pump 25. As the second regulator valve 29 is controlled by the fuel selector 42, low-octane gasoline is supplied to the injector 59 of the engine 11 (step S12).

On the other hand, if it is determined in step S11 that the actual cooling water temperature Tw is not less than the predetermined temperature Ts (No route in step S11), the fuel selection unit 42 of the ECU 14 causes the second regulator pressure _PR2 and the second By controlling the second regulator valve 29 and the third regulator valve 30 so that the 3 regulator pressure P _R3 becomes smaller than the discharge pressure P _P1 of the first fuel pump 25, the base gasoline is injected into the injector 59 of the engine 11. (Step S21).

That is, as shown in the graph of FIG. 2, the predetermined temperature T _S is the temperature (threshold value) of the cooling water that serves as a reference for selecting low octane gasoline and base gasoline, and the actual temperature T _{W of the} cooling water is When the predetermined temperature T _S is exceeded, it is a temperature at which it is considered that the warming of the engine 11 has ended. Note that, as will be described again in the description of steps S16 and S17, even when the predetermined time t ₁ has elapsed after the engine 11 has been started, it is considered that the warm-up of the engine 11 has ended.

Then, in step S13, when it is operated as an ignition switch (not shown) is turned on, the timer value t _n by a timer built in the ECU14 in step S14 (not shown) is reset zero by the driver It becomes.
Thereafter, in step S15, when the target water temperature changing unit 41 determines again that the actual temperature T _W of the cooling water is lower than the predetermined temperature T _S (Yes route of step S15), the timer starts counting up, until the timer value t _n is greater than t _1, i.e., the predetermined time t ₁ until elapsed, step S15~S17 are repeated.

When the predetermined time t ₁ has elapsed (Yes route of step S17), the fuel regulator 42 causes the second regulator pressure P _R2 and the third regulator pressure P _{R3 to} be higher than the discharge pressure P _P1 of the first fuel pump 25. By controlling the second regulator valve 29 and the third regulator valve 30 so as to decrease, the base gasoline is supplied to the injector 59 of the engine 11 (step S18).

On the other hand, when the target water temperature changing unit 42 determines that the actual temperature T _W of the cooling water is equal to or higher than the predetermined temperature T _{S in} Step S15 (No route of Step S15), the process proceeds to Step S18.
That is, when the engine 11 is started, the engine 11 is gradually warmed, so that the cooling water temperature T _W gradually increases and becomes _{equal to} or higher than the predetermined temperature T _S. In this case, the base gasoline is supplied to the engine 11 as described above with reference to FIG. This control is control that reaches step S18 via the No route of step S15.

On the other hand, even if the cooling water temperature T _W is not equal to or higher than T _S , if the predetermined time t ₁ has elapsed after the engine 11 is started, it is considered that the warming up of the engine 11 has been completed. 11 is supplied with base gasoline. This control is a control that leads to step S18 via the Yes route of step S17. This is because the low octane number gasoline stored in the second gasoline tank 17 is used up, and the low octane number gasoline is started at the next start. Is a control for preventing a situation in which the engine 11 cannot be supplied to the engine 11 from occurring.

In this way, when base gasoline is selected as the fuel supplied to the engine 11, the target water temperature changing unit 41 sets the target cooling water temperature T _T to the first target water temperature T _T1 , and this first target water temperature T The opening degree of the thermostat 13 corresponding to _T1 is read out from a memory (not shown) as a map value and transmitted to the thermostat as a thermostat opening degree signal (step S19).
The thermostat 13 that has received the thermostat opening degree signal controls the flow rate of the cooling water flowing between the radiator 12 and the engine 11 (step S20), and proceeds to step S24 in FIG.

On the other hand, if it is determined in step S11 that the actual cooling water temperature Tw is not lower than the predetermined temperature Ts, base gasoline is supplied to the injector 59 of the engine 11 (step S21), and then the target water temperature change of the ECU 14 is changed. The unit 41 sets the target cooling water temperature T _T to the first target water temperature T _T1 , reads the opening degree of the thermostat 13 corresponding to the first target water temperature T _T1 as a map value from a memory (not shown), and outputs a thermostat opening degree signal. Is transmitted to the thermostat 13 (step S22). Thereafter, when the driver operates the ignition switch (not shown) to turn on, the process proceeds to step S24 in FIG.

In step S24, the target water temperature changing unit 41 determines whether or not the actual temperature T _W of the cooling water is _{equal to} or higher than the first target water temperature T _T1 . Here, when it is determined that the actual temperature T _W of the cooling water is _lower than the first target water temperature T _T1 (No route of Step S25), the actual temperature T _W of the cooling water is equal to or higher than the first target water temperature T _T1. Steps S18 to S20 shown in FIG.

On the other hand, when it is determined that the actual temperature T _W of the cooling water is equal to or higher than the first target water temperature T _T1 (Yes route in step S24), the fuel selection unit 42 of the ECU 14 causes the third regulator pressure _{PR3 to} be The third regulator valve 30 is controlled to be larger than the discharge pressure P _P1 of the first fuel pump 25, and the second regulator pressure P _R2 is smaller than the discharge pressure P _P1 of the first fuel pump 25. By controlling the second regulator valve 29, high octane gasoline is supplied to the injector 59 of the engine 11 (step S25).

At this time, the target water temperature changing unit 41 sets the target cooling water temperature T _T to the second target water temperature T _T2 , reads the thermostat opening corresponding to the second target water temperature T _T2 from a memory (not shown) as a map value, It transmits to the thermostat 13 as a thermostat opening degree signal (step S26).
The thermostat 13 which has received the thermostat opening signal opening degree corresponding to the second target temperature T _T2 is in accordance with the thermostat opening signal, for controlling the flow rate of the cooling water flowing between the radiator 12 and the engine 11 (Step S27).

The second target water temperature T _T2 is higher than the first target water temperature T _T1 set when base gasoline or low octane gasoline is supplied to the engine 11 as shown in FIG. It is set when gasoline is supplied to the engine 11. This control is based on the viewpoint that high-octane gasoline has a high boiling point and excellent knock resistance, and by increasing the engine temperature as much as possible, friction loss due to oil viscosity can be reduced and the fuel consumption of the engine 11 can be achieved. Can be raised as much as possible.

Thereafter, when the remaining amount of high-octane gasoline stored in the third gasoline tank 18 becomes less than a predetermined amount (Yes route of step S28), the fuel selector 42 causes the second regulator pressure _PR2 and the third regulator pressure P to be stored. _The base gasoline is supplied to the injector 59 of the engine 11 by controlling the second regulator valve 29 and the third regulator valve 30 so that _R3 becomes smaller than the discharge pressure P _P1 of the first fuel pump 25. (Step S29).

In this case, the target temperature changing unit 41 changes the target coolant temperature T _T from the second target temperature T _T2 to the first target temperature T _T1, not shown thermostat opening corresponding to the first target temperature T _T1 The map value is read from the memory and transmitted to the thermostat 13 as a thermostat opening degree signal (step S30).
The thermostat 13 which has received the thermostat opening degree signal corresponding to the first target temperature T _T1 controls the flow rate of the cooling water flowing between the radiator 12 and the engine 11 in accordance with the received thermostat opening signal (step S31).

In this manner, according to the cooling control apparatus for an internal combustion engine according to a first embodiment of the present invention, it is possible to change the target coolant temperature T _T of the engine 11 in accordance with the octane number is a parameter that correlates to the boiling point of the gasoline Thus, friction loss due to oil viscosity can be reduced, and fuel consumption can be improved.
Further, by setting the target temperature of the cooling water (target cooling water temperature T _T ) higher as the octane number of gasoline supplied to the engine 11 becomes higher, the oil viscosity is reduced while avoiding self-ignition of gasoline, that is, knocking. It can reduce and can contribute to improvement in fuel consumption.

Further, when the engine 11 is started, the startability is improved by using low-octane gasoline. On the other hand, after the warm-up of the engine 11 is finished, the oil viscosity can be reduced by increasing the temperature of the engine 11 by using high-octane gasoline. it can.
Further, when the remaining amount of high octane gasoline stored in the third gasoline tank 18 becomes a predetermined amount or less, base fuel that is fuel before being fractionated into low octane gasoline and high octane gasoline. When the engine 11 is used for the operation of the engine 11, even when low-octane gasoline or high-octane gasoline is insufficient, reliability can be improved by reliably operating the engine 11.

Next, a cooling control apparatus for an internal combustion engine according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a schematic block diagram of the internal combustion engine, and FIGS. 6 and 7 are schematic flowcharts showing the operation thereof. It is.
Note that the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted. Here, the description will focus on differences from the first embodiment. In some cases, the diagram used to describe the first embodiment is used.

The difference between the configuration of the first embodiment described with reference to FIG. 1 and the configuration of the second embodiment shown in FIG. 5 is that an ECU 70 includes a load detection unit 71 and an ignition timing control unit 72. It is a point provided as software.
Among these, the load detection unit 71 determines that the engine 11 has a high load when the intake manifold pressure measured by the intake manifold pressure sensor 60 is larger than a predetermined value.

The ignition timing control unit 72 controls the ignition timing of the spark plug 56 of the engine 11. More specifically, the ignition timing control unit 72 determines that the engine 11 has a high load by the load detection unit 71. When the high-octane gasoline is supplied to the engine 11 by the fuel selector 42, the ignition timing is advanced.
Since the internal combustion engine cooling control apparatus according to the second embodiment of the present invention is configured as described above, the following operations and effects are achieved.

First, as shown in step S41 of FIG. 6, the target water temperature changing unit 41 of the ECU 14 determines whether or not the actual temperature T _W of the cooling water detected by a water temperature sensor (not shown) is less than a predetermined temperature T _S. Is done. Here, when it is determined that the actual cooling water temperature T _W is lower than the predetermined temperature T _S (Yes route of step S41), the fuel selection unit 42 of the ECU 14 causes the third regulator pressure _{PR3 to} be The third regulator valve 30 is controlled so as to be lower than the discharge pressure P _P1 of the fuel pump 25, and the second regulator pressure P _R2 is set so as to be higher than the discharge pressure P _P1 of the first fuel pump 25. By controlling the regulator valve 29, low-octane gasoline is supplied to the injector 59 of the engine 11 (step S42).

Then, in step S43, when it is operated as an ignition switch (not shown) is turned on, the timer value t _n by a timer built in the ECU14 in step S44 (not shown) is reset zero by the driver It becomes.
Thereafter, in step S45, when the target water temperature changing unit 41 determines that the actual temperature T _W of the cooling water is lower than the predetermined temperature T _S (Yes route of step S45), the timer starts counting up, and the timer Steps S45 to S47 are repeatedly executed until the value t _n exceeds t _1, that is, until the predetermined time t ₁ elapses.

When the predetermined time t ₁ has elapsed (Yes route in step S47), the third regulator pressure P _R3 is set to be higher than the discharge pressure P _P1 of the first fuel pump 25 by the fuel selection unit 42. The valve 30 is controlled, and the second regulator valve 29 is controlled so that the second regulator pressure P _R2 becomes smaller than the discharge pressure P _P1 of the first fuel pump 25, so that high octane gasoline is supplied to the engine 11. The fuel is supplied to the injector 59 (step S48).

On the other hand, when the target water temperature changing unit 42 determines in step S45 that the actual temperature T _W of the cooling water is equal to or higher than the predetermined temperature T _S (No route in step S45), the process proceeds to step S48.
If it is determined in step S41 that the actual coolant temperature Tw is not less than the predetermined temperature Ts (No route), the fuel selector 42 causes the second regulator pressure _PR2 and the third regulator pressure _{PR3 to be used.} However, the base gasoline is supplied to the injector 59 of the engine 11 by controlling the second regulator valve 29 and the third regulator valve 30 so as to be smaller than the discharge pressure P _P1 of the first fuel pump 25 ( Step S49). Thereafter, the target water temperature changing unit 41 of the ECU 14, the target coolant temperature T _T is set to the first target temperature T _T1, map values from the memory (not shown) the opening of the thermostat 13 corresponding to the first target temperature T _T1 As a thermostat opening degree signal and transmitted to the thermostat 13 (step S50). Thereafter, when the driver operates the ignition switch (not shown) to turn on, the process proceeds to step S48, and high octane gasoline is supplied to the engine 11.

In step S52 shown in FIG. 7, the load detection unit 71 determines whether or not the engine load T _EGN exceeds a predetermined value X. Here, if it is determined that the engine load T _EGN exceeds the predetermined value X (Yes route of step S52), the ignition timing control unit 72 of the ECU 70 remains at the first target water temperature T _{T1 while} keeping the target water temperature T _T as the first target water temperature T _T1. However, by increasing the ignition timing (step S53), the output of the engine 11 can be improved.

On the other hand, when it is determined that the engine load T _EGN is equal to or less than the predetermined value X (No route of step S52), the target water temperature changing unit 41 sets the target cooling water temperature T _T to the second target water temperature T _T2. , it reads as a map value from the second target temperature T _T2 not shown thermostat opening degree corresponding to the memory, and transmits it to the thermostat 13 as the thermostat opening signal (step S54).

The thermostat 13 which receives the opening degree corresponding to the second target temperature T _T2 as thermostat opening signal in accordance with the thermostat opening signal, for controlling the flow rate of the cooling water flowing between the radiator 12 and the engine 11 (Step S55). At this time, the ignition timing is retarded. (Step S56).
Thereafter, when it is determined in step S57 that the remaining amount of high-octane gasoline stored in the third gasoline tank 18 has become less than a predetermined amount (Yes route of step S57), the fuel selector 42 By controlling the second regulator valve 29 and the third regulator valve 30 so that the 2 regulator pressure P _R2 and the third regulator pressure P _R3 are smaller than the discharge pressure P _P1 of the first fuel pump 25, the base Gasoline is supplied to the injector 59 of the engine 11 (step S58).

At this time, it is determined whether the target temperature T _T is set to the second target temperature T _T2 (step S59), if it is set to the second target temperature T _T2 (Yes route), the target temperature changing unit 41 sets the target cooling water temperature T _T to the first target water temperature T _T1 , reads the thermostat opening corresponding to the first target water temperature T _T1 from a memory (not shown) as a map value, and reads the read thermostat opening to the thermostat It transmits to the thermostat 13 as an opening degree signal (step S60).

And the thermostat 13 controls the flow volume of the cooling water which distribute | circulates between the radiator 12 and the engine 11 according to the received thermostat opening degree signal (step S61).
Also, when the target temperature T _T is not set to the second target temperature T _T2 (No route in step S59), it sets so as to retard the ignition timing is set advance angle (step S62).
Thus, according to the cooling control apparatus for an internal combustion engine according to the second embodiment of the present invention, in addition to the effects of the first embodiment described above, high octane gasoline is supplied to the engine 11 and the load on the engine 11 is high. In this case, the engine output can be improved by advancing the ignition timing of the engine 11.

Further, when high octane gasoline is supplied to the engine 11 and the load of the engine 11 is low, the second target water temperature T _{T2 that} is higher than the first target water temperature T _T1 set when the base gasoline is supplied to the engine 11. By setting, oil viscosity can be reduced and the fuel consumption of the engine 11 can be greatly improved.
In the second embodiment, when high-octane gasoline is supplied, either control of ignition timing advance or high water temperature setting is selected. However, if knocking or the like does not occur, both controls are selected. May be used simultaneously.

The first and second embodiments of the present invention have been described above, but the present invention is not limited to such embodiments, and various modifications can be made without departing from the spirit of the present invention.
In the above-described embodiment, as described for steps S16 and S17 in FIG. 3, the engine 11 is started for a predetermined time t ₁ regardless of whether or not the actual temperature of the cooling water is equal to or higher than T _S. However, instead of such control, the amount of low-octane gasoline stored in the second gasoline tank 17 is less than or equal to a predetermined amount. In such a case, even when the actual temperature T _W of the cooling water is not equal to or higher than the predetermined temperature T _S , the supply of the low-octane gasoline to the engine 11 is stopped, and instead, the base gasoline is supplied to the engine. Also good.

In the above-described embodiment, when high octane gasoline is supplied to the engine 11, the target water temperature changing unit 41 sets the target cooling water temperature T _T to the second target water temperature T _T2 , while the low octane number is When gasoline is supplied to the engine 11, the target cooling water temperature T _T is set to the first target water temperature T _T1 (where the first target water temperature T _T1 <the second target water temperature T _T2 ). has been described as an example, but the invention is not limited to such an example, for example, it sets higher gradually target coolant temperature T _T as the octane number of the gasoline to be supplied to the engine 11 is increased, whereas The target cooling water temperature T _T may be set gradually lower as the octane number of gasoline supplied to the engine becomes lower.

1 is a schematic block diagram illustrating an overall configuration of a cooling control apparatus for an internal combustion engine according to a first embodiment of the present invention. It is a typical graph which shows the relationship between the cooling water temperature of an internal combustion engine, and the octane number of a fuel in the cooling control apparatus of the internal combustion engine which concerns on 1st Embodiment of this invention. It is a typical flowchart which shows the effect | action of the cooling control apparatus of the internal combustion engine which concerns on 1st Embodiment of this invention. It is a typical flowchart which shows the effect | action of the cooling control apparatus of the internal combustion engine which concerns on 1st Embodiment of this invention. It is a typical block diagram which shows the whole structure of the cooling control apparatus of the internal combustion engine which concerns on 2nd Embodiment of this invention. It is a typical flowchart which shows the effect | action of the cooling control apparatus of the internal combustion engine which concerns on 2nd Embodiment of this invention. It is a typical flowchart which shows the effect | action of the cooling control apparatus of the internal combustion engine which concerns on 2nd Embodiment of this invention.

Explanation of symbols

11 Engine (Internal combustion engine)
13 Electronically controlled thermostat (water temperature control means)
15 Gasoline fractionator (Fuel fractionator)
41 Target water temperature changing part (Target water temperature changing means)
42 Fuel selection unit (fuel selection means)
71 Load detection unit (load detection means)
72 Ignition timing changing section (Ignition timing changing means)

Claims (5)

Water temperature control means for controlling the temperature of the cooling water for cooling the internal combustion engine to be the target cooling water temperature;
A cooling control apparatus for an internal combustion engine, comprising: target water temperature changing means for changing the target cooling water temperature in accordance with an octane number of fuel supplied to the internal combustion engine. The target water temperature changing means is:
2. The cooling control device for an internal combustion engine according to claim 1, wherein the target cooling water temperature is set higher as the octane number of the fuel becomes higher. Fuel fractionation means for fractionating a part of the fuel into a low octane fuel and a high octane fuel;
When the internal combustion engine is started, the low octane number fuel fractionated by the fuel fractionation means is supplied to the internal combustion engine, and after the warming up of the internal combustion engine is finished, the high octane number fractionated by the fuel fractionation means. 3. The cooling control device for an internal combustion engine according to claim 1, further comprising fuel selection means for supplying fuel to the internal combustion engine. The fuel selection means includes
4. The non-fractionated base fuel is supplied to the internal combustion engine when the remaining amount of high-octane fuel fractionated by the fuel fractionating means becomes a predetermined amount or less. The internal combustion engine cooling control apparatus. Load detecting means for detecting the load of the internal combustion engine;
Ignition timing changing means for changing the ignition timing of the internal combustion engine;
The ignition timing changing means is ignited when the fuel selection means supplies the high octane fuel to the internal combustion engine and the load detection means detects that the load of the internal combustion engine is high. 4. The control apparatus for an internal combustion engine according to claim 3, wherein the timing is advanced.

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