JP2008075467A - Fuel controller for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To start operation of an internal combustion engine at low temperature securely by a simple configuration to improve fuel economy. <P>SOLUTION: In this fuel controller for the internal combustion engine provided with an on-vehicle fuel separator 30 for separating gasoline from alcohol mixed gasoline and operating the on-vehicle fuel separator 30 if amount of gasoline stored in a subtank 33 for gasoline does not reach the amount demanded at operation start time of the engine 10 at low temperature to increase the amount of stored gasoline, concentration of gasoline in the alcohol mixed gasoline is obtained before operating the on-vehicle fuel separator 30, and insufficient amount of gasoline is displayed in a display part 42 without operating the on-vehicle fuel separator 30, that is, without driving a feed pump 21, etc. if the concentration is zero (concentration of alcohol is 100%) to urge a user to feed gasoline into a vehicle. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel control device for an internal combustion engine, and more specifically, can ensure a low temperature start of the internal combustion engine with a simple configuration and can contribute to an improvement in fuel consumption. About.

  In recent years, in order to cope with the diversification of automobile fuel, a flexible fuel vehicle (FFV) using a fuel in which alcohol such as ethanol is mixed with gasoline has been developed.

  Alcohol has a higher latent heat of vaporization than gasoline and is difficult to evaporate at low temperatures, so that the formation of an air-fuel mixture tends to be insufficient. Further, in a region where the use of ethanol is influenced by the user, such as in Brazil, gasoline fuel with a high vapor pressure is not always used at low temperatures such as in winter. Therefore, when the high-concentration alcohol fuel is used at the time of low temperature such as winter during the operation of the FFV, it may be difficult to start the internal combustion engine.

  For this reason, when using high-concentration alcohol mixed gasoline, there is a technology that promotes fuel vaporization by heating the injector for fuel injection or heating the engine block in order to ensure low temperature startability of the internal combustion engine. Various are provided.

  In addition, in the United States and other countries, measures such as controlling the properties of high-concentration alcohol blended gasoline in the fuel supply market in the summer and winter, and increasing the vapor pressure of the fuel to ensure low temperature startability of the internal combustion engine in the winter, etc. Has been made.

  However, the provision of the heating means such as the injector has a problem that the apparatus becomes complicated and the cost is increased, and the voltage load of the battery is increased and the fuel consumption is deteriorated. Even in areas where fuel properties are controlled in the fuel supply market, it may be possible to run in the winter with fuel supplied in the summer, so the temperature may be reduced depending on the properties of the fuel used during the current operation. It is necessary to ensure startability.

  Therefore, a technology capable of ensuring low temperature startability according to the properties of the fuel used during the current operation with a simple configuration has been proposed. For example, an in-vehicle fuel separator that separates gasoline from alcohol-mixed gasoline is proposed. In order to ensure a sufficient amount of gasoline required for starting the internal combustion engine, a technology for improving startability by injecting gasoline after operating the on-vehicle fuel separator for a predetermined time has been proposed ( For example, see Patent Document 1).

  As another related technology, a fuel control device for an alcohol engine using alcohol fuel as a main fuel and gasoline as an auxiliary fuel, and a technology for improving startability by injecting gasoline from an auxiliary injector at a low temperature start is proposed. (For example, see Patent Document 2 and Patent Document 3).

Japanese Utility Model Publication No. 3-42035 JP-A-2-149758 JP-A-2-149759

  However, even in the conventional technique according to Patent Document 1, when the fuel used during the current operation has an alcohol concentration of 100%, the fuel does not contain gasoline, so the gasoline should be separated. No matter how many on-board fuel separators are operated, separation is impossible and the required amount of gasoline cannot be secured. For this reason, the low temperature startability of the internal combustion engine is deteriorated, and the in-vehicle fuel separator is operated wastefully, which causes an increase in battery voltage load and the like, resulting in deterioration of fuel consumption.

  The present invention has been made in view of the above, and provides a fuel control device for an internal combustion engine that can ensure a low temperature start of the internal combustion engine with a simple configuration and contribute to an improvement in fuel consumption. The purpose is to provide.

  In order to solve the above-described problems and achieve the object, a fuel control device for an internal combustion engine according to claim 1 of the present invention provides an in-vehicle fuel separation device that separates a second fuel having different properties from a first fuel. An internal combustion engine that operates the on-vehicle fuel separation device to increase the storage amount of the second fuel when the storage amount of the second fuel is less than the amount required during a predetermined operation of the internal combustion engine. In the fuel control device, the concentration of the second fuel in the first fuel is obtained before the operation of the in-vehicle fuel separation device, and when the concentration is equal to or less than a predetermined value, the in-vehicle fuel separation device is operated. Without being noticed that the second fuel is insufficient.

  Therefore, according to the present invention, when the fuel to be supplied does not include the second fuel of a predetermined amount or more, the on-vehicle fuel separation device is not operated, so the on-vehicle fuel separation device is operated wastefully. You don't have to. Further, since the fact that the second fuel is insufficient is notified, the user can refuel quickly.

  According to a second aspect of the present invention, there is provided a fuel control apparatus for an internal combustion engine according to the first aspect, wherein the first fuel is alcohol-mixed gasoline, and the second fuel is gasoline. The second fuel is injected at the time of starting.

  Therefore, according to the present invention, when applied to an internal combustion engine using alcohol-mixed gasoline, which is a fuel with a large amount of circulation, and gasoline, low temperature startability is ensured by gasoline injection, and great energy saving is achieved by improving fuel efficiency. Is realized.

  According to the fuel control device for an internal combustion engine according to the present invention (Claim 1), since it is not necessary to operate the on-vehicle fuel separation device wastefully and the second fuel is insufficient, With a simple configuration, it is possible to reliably start the internal combustion engine at a low temperature and to contribute to an improvement in fuel consumption.

  In addition, according to the fuel control device for an internal combustion engine according to the present invention (Claim 2), since it can be applied to an internal combustion engine using alcohol-mixed gasoline and gasoline, which are fuels with a large amount of circulation, gasoline injection As a result, low temperature startability can be ensured, and great energy savings can be realized by improving fuel consumption.

  Embodiments of a fuel control device for an internal combustion engine according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 is a block diagram showing a system configuration of a fuel control device for an internal combustion engine according to an embodiment of the present invention. As shown in FIG. 1, fresh air is drawn into the combustion chamber 10 a of each cylinder of an engine (internal combustion engine) 10 mounted on a vehicle from an air cleaner 11 through an intake manifold 13 in an intake passage 12. ing.

  The intake passage 12 is provided with an electromagnetic injector 15 so as to inject alcohol-mixed gasoline (first fuel) or gasoline (second fuel) from a delivery pipe 14 adjusted to a predetermined pressure. Yes. The injector 15 is controlled by an electronic control unit (hereinafter referred to as ECU) 40 and injects the fuel (a control line with the ECU 40 is not shown). Exhaust gas from the engine 10 is discharged from an exhaust passage 16, and an exhaust purification catalyst 17 is provided in the exhaust passage 16.

  The main fuel tank 20 is for storing alcohol-mixed gasoline. The fuel in the main fuel tank 20 is sent to the main fuel flow path 22 by the feed pump 21. The mixed fuel in the main fuel flow path 22 is supplied to the delivery pipe 14 via the electromagnetic three-way valve 25 and the common fuel flow path 26. Further, a part of the main fuel flow path 22 communicates with an in-vehicle fuel separation device 30 described later via an electromagnetic valve 28.

  By switching the three-way valve 25, the common fuel flow path 26 allows either one of alcohol-mixed gasoline supplied from the main fuel flow path 22 or gasoline supplied from a sub fuel flow path 35 to be described later. ing. The common fuel flow path 26 is provided with an alcohol concentration sensor 27 that detects the alcohol concentration in the alcohol-mixed gasoline.

  The gasoline sub-tank 33 is for storing only genuine gasoline, and is connected by an on-vehicle fuel separation device 30 and a gasoline separation passage 34 described later. The gasoline in the gasoline sub tank 33 is supplied to the delivery pipe 14 via the sub fuel flow path 35, a feed pump (not shown), the three-way valve 25, and the common fuel flow path 26. The level sensor 36 is for detecting the remaining amount of gasoline in the gasoline sub tank 33.

  The on-vehicle fuel separation device 30 is for separating the alcohol-mixed gasoline in the main fuel tank 20 into alcohol and gasoline using a separation membrane (not shown) when necessary, and is configured by a known technique. . That is, the in-vehicle fuel separation device 30 uses gasoline separated from alcohol-mixed gasoline to improve the low temperature startability of the engine 10 and to improve the exhaust properties during cold operation.

  When the on-vehicle fuel separator 30 is operated, the flow from the main fuel flow path 22 to the common fuel flow path 26 is blocked by switching the three-way valve 25, while the electromagnetic valve 28 is opened to feed the feed pump 21. To feed the alcohol-mixed gasoline in the main fuel tank 20 to the on-vehicle fuel separator 30.

  The gasoline separated by the in-vehicle fuel separator 30 flows through the gasoline separation flow path 34, is introduced into the gasoline sub tank 33, and is stored in the gasoline sub tank 33. When the engine 10 is started at a low temperature, the sub fuel passage 35 and the common fuel passage 26 are communicated by switching the three-way valve 25 and the feed pump (not shown) is driven to deliver gasoline in the gasoline sub tank 33. It is supplied to the injector 15 through the pipe 14. Further, by injecting gasoline having a high vapor pressure from the injector 15 even at a low temperature, the engine 10 can be reliably started at a low temperature.

  The alcohol separated by the in-vehicle fuel separator 30 is returned to the main fuel tank 20 by the return flow path 38.

  The ECU 40 receives input signals from various sensors which will be described later, and performs arithmetic processing based on the input signals, such as an injector 15, an ignition plug (not shown), a three-way valve 25, an electromagnetic valve 28, a feed pump 21, a display unit 42 which will be described later, and the like. Control the operation. That is, as will be described later, the ECU 40 is configured to perform the fuel injection amount, ignition timing, gasoline separation operation from the mixed fuel, a predetermined warning, etc. according to the operation status of the FFV and the properties and remaining amount of the fuel to be used. Has been.

  As the various sensors, in addition to the alcohol concentration sensor 27 and the level sensor 36, although not shown, a temperature sensor and a pressure sensor for detecting the temperature and pressure of the fuel in the delivery pipe 14 and the crankshaft rotation of the engine 10 are detected. Crank position sensor, intake air temperature sensor that detects intake air temperature, intake pressure sensor that detects intake air pressure, accelerator opening sensor that detects the amount of accelerator pedal depression (accelerator opening), throttle that detects the opening of the throttle valve A position sensor, a water temperature sensor that detects the cooling water temperature of the engine 10, an air-fuel ratio sensor that detects the exhaust air-fuel ratio in the exhaust passage 16, and the like can be given.

  In addition, the display unit 42 is disposed, for example, on an instrumental panel in front of the driver's seat and displays various information necessary for driving. In this embodiment, in particular, a start failure of the engine 10 occurs due to gasoline shortage. This is used to warn that there is a possibility of fueling or to warn the user to refuel gasoline.

  Next, a control method according to the present embodiment will be described. This control is for the case where the fuel currently used by the FFV is high-concentration alcohol mixed gasoline (for example, alcohol concentration of 85% or more), and the remaining amount of gasoline required for the low temperature start of the engine 10 is below a predetermined value. In this case, it is intended to promote the separation of gasoline from the mixed fuel to ensure the necessary amount of gasoline and to warn the user to refuel the gasoline.

  This control method will be described in detail with reference to FIG. 1 based on FIG. Here, FIG. 2 is a flowchart showing a control method. The following control is executed by the ECU 40.

  First, when the ignition switch (IG) is turned on (step S10), the alcohol concentration Cal in the fuel is measured by the alcohol concentration sensor 27 (step S11). If the measured alcohol concentration Cal is equal to or less than a predetermined threshold, for example, 85% (E85) or less (No at Step S12), the gasoline concentration is relatively high, and it is considered that low temperature start failure of the engine 10 is unlikely to occur. Therefore, control ends.

  On the other hand, if the measured alcohol concentration Cal exceeds a predetermined threshold value, for example, 85% (E85) (Yes at Step S12), the gasoline concentration is low and a low temperature start failure of the engine 10 may occur. Therefore, it is necessary to perform start-up operation with gasoline having a high vapor pressure even at low temperatures.

  In this case, it is confirmed whether the gasoline amount required for starting the engine 10, that is, the engine starting start required gasoline amount Lok is secured in the gasoline sub-tank 33. When the operation shifts to start-up control with another routine of gasoline, if it is not secured, it is necessary to promote the separation of gasoline from the mixed fuel to secure the required amount.

  Therefore, the engine start start request gasoline amount Lok is calculated (step S13), and the gasoline remaining amount Lv in the gasoline sub-tank 33 is measured by the level sensor 36 (step S14). Then, it is determined whether or not the remaining amount Lv of gasoline in the gasoline sub tank 33 is smaller than the engine start start requested gasoline amount Lok calculated in step S13 (step S15).

  If the gasoline remaining amount Lv in the gasoline sub-tank 33 is smaller than the engine start start requested gasoline amount Lok (Yes at Step S15), a start failure of the engine 10 may occur due to a shortage of gasoline, so that warning is given. (Step S16).

  This warning is displayed, for example, on the display unit 42 disposed on the instrument panel in front of the driver's seat of the FFV, or by voice or buzzer sound. As a result, the user can recognize the necessity of gasoline refueling and can quickly refuel, so that it is possible to avoid the occurrence of a failure when the engine is cold started.

  When the gasoline remaining amount Lv in the gasoline sub-tank 33 is not less than the engine start request gasoline amount Lok (No at Step S15), the necessary amount of gasoline is secured and the possibility of occurrence of a start failure is low. Since the warning is not necessary, the present control may be terminated and the routine may be shifted to a starting operation control using gasoline, which is different from the present control.

  After warning in step S16, it is determined whether the alcohol concentration in the main fuel tank 20 is not 100% (E100) (step S17). If the alcohol concentration in the main fuel tank 20 is 100% (E100) (No in step S17), that is, if the gasoline concentration is zero, the user is warned to supply only the gasoline to the main fuel tank 20. (Step S21), and this control is finished.

  In this case, since the gasoline to be separated is not in the main fuel tank 20, the solenoid valve 28, the three-way valve 25 and the feed pump 21 necessary for gasoline separation are not operated. Thereby, useless energy consumption can be avoided and an increase in the voltage load of a battery (not shown) can be avoided, so that deterioration of fuel consumption can be suppressed.

  Further, the warning in step S21 can also be displayed on the display unit 42, or by sound or sound generation by a buzzer, as in the case of warning of the possibility of the start failure of the engine 10 described above. Thereby, since the user can recognize the necessity of gasoline refueling and can perform gasoline refueling quickly, it is possible to ensure alcohol-mixed gasoline having an appropriate concentration.

  As a result, even when the gasoline amount necessary for starting the engine 10 at a low temperature is not stored in the gasoline sub-tank 33, the necessary gasoline amount can be secured by promoting gasoline separation described later. In addition, it is possible to avoid the occurrence of defects during cold start.

  On the other hand, if the alcohol concentration in the main fuel tank 20 is not 100% (E100) (Yes at Step S17), the solenoid valve 28 of the gasoline separation passage 34 is opened (Step S18), and the driving force of the feed pump 21 is set. Is gradually increased from the zero state to increase the pressure feeding (step S19), and the gasoline separation (extraction) from the alcohol-mixed gasoline is promoted to increase the gasoline remaining amount Lv of the gasoline sub-tank 33.

  Then, it is determined whether or not the gasoline remaining amount Lv in the gasoline sub-tank 33 exceeds the engine start start request gasoline amount Lock (step S20). If it exceeds, the control is terminated (Yes in step S20) and does not exceed. In this case, the gasoline separation promotion control is continued until it exceeds (No at Step S20, Step S18, Step S19).

  By controlling as described above, the gasoline remaining amount Lv of the gasoline sub-tank 33 can be increased in a short time, so that a stable low-temperature start operation by gasoline can be realized, and the occurrence of a low-temperature start failure of the engine 10 can be avoided. can do.

  Further, when the separation of gasoline from the mixed fuel in the main fuel tank 20 is promoted in this way, the gasoline concentration in the main fuel tank 20 is lowered, so that the necessity of gasoline refueling is increased. However, in step S16 described above, Since the user is prompted to refuel by warning, it can be expected that quick refueling will be performed.

  As described above, according to the fuel control apparatus for an internal combustion engine according to this embodiment, the fuel currently used by the FFV is high-concentration alcohol mixed gasoline, and the remaining amount of gasoline necessary for low-temperature start of the engine 10 Even when the amount of fuel is small, the separation of gasoline from alcohol-mixed gasoline can be promoted to secure the required amount of gasoline, and the user can be prompted to refuel with gasoline, so the engine 10 can be started at a low temperature. Can be ensured.

  In particular, when the gasoline to be separated is not in the main fuel tank 20, by not operating the feed pump 21 and the like necessary for gasoline separation, it is possible to avoid wasteful energy consumption and contribute to improvement in fuel consumption. .

  Further, in the present embodiment, the present invention is applied to the engine 10 using alcohol-mixed gasoline and gasoline, which are fuels with a large amount of fuel distributed worldwide, so that low temperature startability can be ensured by gasoline injection, Significant energy savings can be realized by improving fuel consumption.

  In the above embodiment, in step S17 of the control operation shown in FIG. 2, as long as gasoline is contained in the main fuel tank 20, the alcohol concentration threshold value is used from the viewpoint of separating gasoline and using it for cold start. However, the present invention is not limited to this. Even if the threshold value is less than 100%, the same effect as described above can be expected.

  In the above embodiment, the embodiment of the present invention is shown in which the first fuel is alcohol-mixed gasoline and the second fuel is gasoline. However, the present invention is not limited to this, and the second fuel is different from the first fuel in properties. If it is a combination of fuels that can separate the fuel, the same effect as described above can be expected.

  Moreover, in the said Example, although demonstrated as what applies this invention to the engine 10 which performs port injection by the injector 15, the injection form (port injection or in-cylinder injection) and the number of arrangement | positioning of an injector are not ask | required.

  For example, the present invention may be applied to an engine provided with an in-cylinder injector instead of the port injector 15. In addition, the present invention may be applied to an engine including an injector that performs gasoline port injection and an injector that injects alcohol into a cylinder.

  As described above, the fuel control device for an internal combustion engine according to the present invention is useful for an FFV internal combustion engine using alcohol-mixed gasoline, and in particular, can ensure a low-temperature start of the internal combustion engine with a simple configuration. It is suitable for an internal combustion engine that aims to contribute to improving fuel efficiency.

1 is a block diagram illustrating a system configuration of a fuel control device for an internal combustion engine according to an embodiment of the present invention. FIG. It is a flowchart which shows a control method.

Explanation of symbols

10 Engine (Internal combustion engine)
DESCRIPTION OF SYMBOLS 14 Delivery pipe 15 Injector 20 Main fuel tank 21 Feed pump 22 Main fuel flow path 25 Three-way valve 27 Alcohol concentration sensor 28 Solenoid valve 30 Car-mounted fuel separator 33 Gasoline sub tank 34 Gasoline separation flow path 35 Sub fuel flow path 36 Level sensor 38 Return flow path 40 ECU
42 Display part Cal Concentration of alcohol in fuel Lv Remaining gasoline in sub tank for gasoline Lok Engine start required gasoline quantity

Claims (2)

An on-vehicle fuel separation device for separating a second fuel having different properties from the first fuel;
When the second fuel storage amount is less than the amount required during a predetermined operation of the internal combustion engine, the fuel control for the internal combustion engine that operates the on-vehicle fuel separation device to increase the second fuel storage amount In the device
Before the operation of the on-vehicle fuel separator, the concentration of the second fuel in the first fuel is obtained, and when the concentration is equal to or less than a predetermined value, the on-vehicle fuel separator is not operated. A fuel control device for an internal combustion engine, which notifies that the second fuel is insufficient.   2. The fuel control for an internal combustion engine according to claim 1, wherein the first fuel is alcohol-mixed gasoline, and the second fuel is gasoline, and the second fuel is injected when the internal combustion engine is started. apparatus.

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