JP2024038897A - Fuel injection control device for internal combustion engine - Google Patents

Abstract

[Problem] In an internal combustion engine that can use either alcohol, gasoline, or a mixed fuel of alcohol and gasoline as fuel, derive the fuel injection amount that allows starting in a short time and reduce battery consumption when starting the internal combustion engine. A fuel injection control device for an internal combustion engine is provided.
[Solution] A fuel injection control device for an internal combustion engine that can use alcohol, gasoline, or a mixed fuel of alcohol and gasoline as a fuel has three or more fuel injection amount control maps, and has three or more fuel injection amount control maps. The fuel injection amount control map M _x immediately before a stop is stored, and when the internal combustion engine 1 is started, the fuel injection amount control _{map M} 1 is determined to be a poor start, the selected fuel injection amount control map M _s is selected. Adjacent injection amount control maps M _S+1 and M _S-1 in the order of the map numbers of the fuel injection amount control map M _S are selected. Switch to quantity control map M _S+2 , M _S-2 .
[Selection diagram] Figure 3

Description

The present invention relates to a fuel injection control device for an internal combustion engine that controls the fuel injection amount at the time of starting an internal combustion engine that has a flexible fuel function and can be operated on gasoline, alcohol, or a mixture of both.

In recent years, from the perspective of global warming, alcohol fuel, especially bioethanol, has been used as an alternative fuel because it is produced from plants grown through photosynthesis using solar energy, so even if energy is extracted from the fuel, the total amount of _CO2 in the atmosphere will not increase. is attracting attention as a carbon-neutral fuel.
Therefore, in place of conventional vehicles equipped with internal combustion engines that use gasoline as fuel, in recent years, internal combustion engines with so-called flexible fuel functions that can be operated on gasoline, alcohol, or alcohol blended fuel (gasoline and alcohol) have been introduced. A vehicle equipped with an engine is used. Internal combustion engines with such flexible fuel functionality have different issues than internal combustion engines that use gasoline.

Alcohol fuel and alcohol-mixed fuel are fuels that contain only alcohol or a mixture of alcohol and gasoline.Due to the combustion characteristics of alcohol, vaporization of the fuel is not promoted at low temperatures, making it difficult for the internal combustion engine to start. Become.

Furthermore, alcohol blended fuels with different mixing ratios are distributed, for example, E100, which is 100% ethanol, E85, which is 85% ethanol mixed with gasoline, E50, which is 50% ethanol mixed with gasoline, and gasoline. There is E25, which is a mixture of ethanol and 25% ethanol.

When supplying fuel, the internal combustion engine is stopped, but if alcohol mixed fuel is supplied to the fuel tank with a concentration different from that before the internal combustion engine was stopped, the alcohol concentration will be different from the alcohol concentration immediately before the engine was stopped, so control should be carried out immediately before the engine is stopped. If the engine is started with the optimal fuel injection amount at the concentration recognized by the device, the fuel injection amount will be insufficient or excessive, making it impossible to start the internal combustion engine.

Therefore, when starting the internal combustion engine, the starting determination means starts the engine at the estimated ethanol concentration value stored in the ECU (engine control unit), and if it is determined that the internal combustion engine has a starting failure, the first ethanol concentration estimation The fuel injection amount is corrected using a second ethanol concentration estimate different from the second ethanol concentration estimate, and if it is determined that the internal combustion engine has a starting failure, a third ethanol concentration estimate different from the second ethanol concentration estimate is used. There is a system that corrects the fuel injection amount (see Patent Document 1).

Japanese Patent Application Publication No. 2007-1469831

In a fuel injection control device for an internal combustion engine equipped with such a flexible fuel function, when the internal combustion engine is started, it is started at the estimated ethanol concentration value stored in the ECU, and the internal combustion engine is determined to have a starting failure. In this case, the estimated value of the ethanol concentration is changed multiple times until the estimation of the ethanol concentration is finished, which causes a problem in that it takes time for the internal combustion engine to start, and the electric capacity of the battery is consumed.

Therefore, in order to solve the above problems, the present invention is used in an internal combustion engine that can use alcohol, gasoline, or a mixed fuel of alcohol and gasoline as fuel.
a fuel tank in which any of the fuels is stored;
a fuel injection device that supplies fuel stored in the fuel tank to an internal combustion engine;
A fuel injection control device for an internal combustion engine that controls a fuel injection amount of the fuel injection device according to an alcohol concentration of the fuel,
having three or more fuel injection amount control maps for controlling the fuel injection amount of the internal combustion engine according to a range of alcohol concentration of the fuel;
The plurality of fuel injection amount control maps (M ₁ , M ₂ , M ₃ , M ₄ ) are sequentially assigned map numbers from the lowest alcohol concentration to the highest alcohol concentration, and
The plurality of fuel injection amount control maps are selected based on the alcohol concentration of the fuel in adjacent fuel injection amount control maps in the map number order of the selected fuel injection amount control map selected based on the alcohol concentration of the fuel. the internal combustion engine is configured to be startable;
When the internal combustion engine is stopped, an immediately before stop fuel injection amount control map immediately before the stop of the internal combustion engine is set as the selected fuel injection amount control map,
When starting the internal combustion engine, selecting the fuel injection amount control map immediately before stopping;
starting the internal combustion engine with a fuel injection amount based on the selected fuel injection amount control map;
When it is determined that the internal combustion engine has a starting failure, the selected fuel injection amount control map is set to the fuel injection amount of the adjacent fuel injection amount control map in the order of the map number of the selected fuel injection amount control map. This fuel injection control device for an internal combustion engine is characterized in that it switches to a control map and starts starting the internal combustion engine.

According to the present invention, in a fuel injection control device for an internal combustion engine that can use alcohol, gasoline, or a mixed fuel of alcohol and gasoline as fuel, a plurality of fuel injection amount control maps are configured based on the alcohol concentration of the fuel. Even in adjacent fuel injection amount control maps in the map number order of the fuel injection amount control maps selected by The immediately-before-stop fuel injection amount control map stored during the previous stop is set as the selected fuel injection amount control map, and the internal combustion engine is started with the fuel injection amount based on the selected fuel injection amount control map, and the internal combustion engine is determined to have a starting failure. In this case, the selected fuel injection amount control map is switched to the fuel injection amount control map that is further adjacent to the adjacent fuel injection amount control map in the map number order of the selected fuel injection amount control map, and starting of the internal combustion engine is started. Therefore, the fuel injection amount that can start the internal combustion engine in a short time is derived, improving the ignition performance when starting the internal combustion engine, improving the starting performance of the internal combustion engine, and reducing battery consumption when starting the internal combustion engine. can do.

In the above configuration, there may be four fuel injection amount control maps.

According to the above configuration, since there are four fuel injection amount control maps, when the internal combustion engine cannot be started within a predetermined time, fuel injection is controlled based on the skipped fuel control map. Therefore, the internal combustion engine can be started by changing the fuel control map only once, so that the startability of the internal combustion engine can be further improved.

The present invention is a fuel injection control device for an internal combustion engine that can be operated with gasoline, alcohol, or a mixture of both. It is possible to improve the ignitability of the engine, improve the startability of the internal combustion engine, and reduce battery consumption when starting the internal combustion engine.

FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 3 is a diagram showing assignment of a plurality of control groups to the mixture ratio of gasoline and ethanol. FIG. 3 is a diagram showing a flow when starting an internal combustion engine. FIG. 3 is a diagram showing an example of selection of a fuel injection amount control map when starting an internal combustion engine. FIG. 3 is a diagram showing an example of selection of a fuel injection amount control map when starting an internal combustion engine. FIG. 3 is a diagram showing an example of selection of a fuel injection amount control map when starting an internal combustion engine. FIG. 3 is a diagram showing an example of selection of a fuel injection amount control map when starting an internal combustion engine. FIG. 3 is a diagram showing an example of a fuel injection amount control map selected based on the alcohol concentration of fuel and fuel injection amount control maps on both sides thereof.

FIG. 1 is a schematic diagram generally showing a fuel injection control device 20 for an internal combustion engine according to the present invention and an internal combustion engine 1 in which the fuel injection control device 20 is used. The internal combustion engine 1 is an internal combustion engine equipped with a so-called flexible fuel function that can be operated with gasoline, alcohol fuel, or a mixture of gasoline and alcohol in any ratio, and is installed in a vehicle (not shown). It is.
For example, ethanol is used as the alcohol fuel. An example of this ethanol is bioethanol, which is produced from plants grown through photosynthesis using sunlight energy.

As shown in FIG. 1, the vehicle is equipped with a fuel tank 5. The fuel tank 5 stores alcohol fuel, a mixed fuel in which alcohol fuel and gasoline are mixed at an arbitrary ratio, or gasoline. The fuel tank 5 is connected via a fuel supply pipe 6 to a fuel injection valve 7 that injects fuel into the intake passage 2 of the internal combustion engine 1 . The fuel injection valve 7 injects an amount of fuel depending on the combustion state of the internal combustion engine 1 and various conditions. In this embodiment, the fuel injection valve 7 is installed so as to inject fuel into the intake passage 2, but it may also be installed so as to directly inject fuel into the combustion chamber of the internal combustion engine 1.

An intake passage 2 through which outside air is supplied is connected to an intake port 1a of the internal combustion engine 1, and an exhaust passage 3 through which exhaust gas after combustion is discharged is connected to an exhaust port 1b of the internal combustion engine.
A throttle valve 8 for controlling the intake flow rate is disposed in the intake passage 2, and a throttle sensor 10 for detecting the throttle opening θth of the throttle valve 8 is attached. Further, in the intake passage 2, a Pb sensor 11 is arranged downstream of the throttle valve 8 to detect intake negative pressure Pb. An oxygen sensor 12 is attached to the exhaust passage 3 to detect the oxygen concentration Vo ₂ in the exhaust gas. The vehicle is provided with an outside temperature sensor 15 that detects outside temperature To.

Furthermore, the internal combustion engine 1 is equipped with a water temperature sensor 13 that detects the cooling water temperature Tw of the internal combustion engine 1, a crank angle sensor 14 that detects the rotational speed Ne of the internal combustion engine, and the like. Detection signals detected by various sensors are sent to an engine control unit 18 (hereinafter referred to as ECU 18).

The ECU 18 monitors whether or not a starter motor (not shown) is driven by the driver's operation of an engine key (not shown) using an ON-OFF signal from the starter switch 9.

In the fuel injection control device 20, as shown in FIG. 2, a plurality of control groups are configured according to the mixing ratio of gasoline and alcohol, that is, a range of alcohol concentration. A method is adopted in which the appropriate fuel injection state is selected and switched by selecting .

A control group is a collection of control items such as a fuel injection amount map, injection timing, and ignition timing, which are items to be controlled based on a predetermined range of alcohol concentration. That is, a collection of these controls is prepared in advance for each control group corresponding to the set alcohol concentration range.

The control groups are divided into a plurality of groups according to a predetermined range of the alcohol concentration of the fuel, and in this embodiment, as shown in FIG. 2, the first control group, the first control group, It is divided into four control groups: a second control group, a third control group, and a fourth control group. In this embodiment, the number of control groups is four, but it does not have to be four, but may be three or more.

In this embodiment, the reference concentrations of the four control groups are assigned within a predetermined range from 0% alcohol (100% gasoline) to 100% alcohol (0% gasoline).
Specifically, in this embodiment, a control group is assigned to each of four levels of alcohol concentration.
Control group numbers are assigned in order from the lowest to the highest median value in the corresponding alcohol concentration range in each control group. That is, the median values of the alcohol concentration ranges corresponding to each control group are set as a first control group, a second control group, a third control group, and a fourth control group in order from lowest to highest.
As shown in FIG. 2, the corresponding alcohol concentration ranges of adjacent control groups in the order of control group numbers are set to partially overlap.

Each control group has its own fuel injection amount control map for controlling the fuel injection amount, and in this embodiment, there are four fuel injection amount control maps. These fuel injection amount control maps are assigned numbers in order from the lowest to the highest median value in the corresponding alcohol concentration range so as to correspond to the control group. That is, in each fuel injection amount control map, the median values in the corresponding alcohol concentration range are arranged in order from low to high in the first fuel injection amount control map M ₁ , the second fuel Map numbers are assigned as an injection amount control map M ₂ , a third fuel injection amount control map M ₃ , and a fourth fuel injection amount control map M ₄ . The fuel injection control device 20 controls the fuel injection amount based on an appropriately selected selected fuel injection amount control map _MS .

These plurality of fuel injection amount control maps M ₁ , M ₂ , M ₃ , M ₄ are adjacent fuel injection amounts in the map number order of the selected fuel injection amount control map M _S selected based on the alcohol concentration of the fuel. The control maps M _S+1 and M _S-1 are also configured so that the internal combustion engine 1 can be started based on the alcohol concentration of the fuel.
For example, as shown in FIG. 8, when the second control group is selected based on the alcohol concentration of the fuel, the second fuel injection amount control map _M2 belonging to the second control group is selected, and the second The fuel injection amount control map _M2 becomes the selected fuel injection amount control map _MS .
In that case, the third fuel injection amount control map M ₃ (fuel injection amount control map M _{S +1 )} and the first Also in the fuel injection amount control map M ₁ (fuel injection amount control map M _S-1 ), each fuel injection amount control map is configured so that the internal combustion engine 1 can be started based on the alcohol concentration of the fuel.

As described above, the ECU 18 selects an appropriate control group depending on the alcohol concentration of the fuel supplied to the internal combustion engine 1. When the internal combustion engine 1 is operating, the fuel injection amount control map is multiplied by a feedback correction number to perform general feedback control that repeats rich and lean so as to obtain an appropriate air-fuel ratio based on the output of the oxygen sensor 12. However, if the feedback correction value is greater than or equal to a predetermined value or less than a predetermined value, that control group is determined to be inappropriate, and the control group is switched to an adjacent control group in a direction that corrects the map deviation. The latest selected control group is always stored in the ECU 18 and is selected first the next time the internal combustion engine 1 is started.

When the internal combustion engine 1 is started, the internal combustion engine 1 is not in a combustion state, so it is not possible to select an appropriate control group based on the output value of the oxygen sensor 12. Therefore, the control group at the time of starting the internal combustion engine 1 is determined based on the flowchart shown in FIG.

First, when the ECU 18 receives an ON signal from the starter switch 9 caused by the driver's operation of the engine key, it determines that a starting operation for the internal combustion engine 1 has started, and the process proceeds to step S2.

In step S2, it is determined whether the outside temperature To detected by the outside temperature sensor 15 is less than or equal to a predetermined value _To1 .

If the outside temperature To is less than or equal to the predetermined value _To1 , the process proceeds to step S3, where the low temperature starting mode is entered. In the low-temperature start mode, a low-temperature start device (not shown), such as a heater that warms fuel piping, an intake passage, etc., is started to start heating fuel and intake air. When the outside temperature is low, the startability of the internal combustion engine decreases due to the reduced vaporization of ethanol at low temperatures, so the low temperature starting device is started to improve the startability of the internal combustion engine 1. After starting the low temperature starting device, the process proceeds to step S5.

If the outside temperature To is not below the predetermined value _To1 , that is, if the outside temperature To is higher than the predetermined value _To1 , the process proceeds to step S4.

In step 4, the control group stored in the ECU 18 immediately before the stop of the internal combustion engine 1 before the current start is selected as the control group for the current start of the internal combustion engine 1, and the control group immediately before the stop as the fuel injection amount control map is selected. The fuel injection amount control map _MX is selected as the selected fuel injection amount control map _MS , and the process then proceeds to step S5.

For example, if the first control group is stored as the control group immediately before stopping the internal combustion engine 1, the first control group is selected as the control group for starting the internal combustion engine 1 this time. Furthermore, when the first control group is selected, the first fuel injection amount control map _M1 in the first control group is selected as the selected fuel injection amount control map MS, and the fuel injection amount control map M1 in the first control group is selected as the selected fuel injection amount control map _MS . Control is performed based on the first fuel injection amount control map _M1 .

Proceeding to step S5, the starting motor of the internal combustion engine 1 is turned on.

Thereafter, the process proceeds to step S6, and after a predetermined period of time has elapsed since the starting motor of the internal combustion engine 1 was turned on, the rotational speed Ne of the internal combustion engine is compared with a predetermined rotational speed _Ne1 . If it is determined in step S6 that Ne is equal to or greater than Ne ₁ , it is determined that the internal combustion engine 1 has been started, and the process proceeds to step S7.

In step S7, the basic starting mode is entered, and the subsequent combustion of the internal combustion engine 1 is controlled based on the selected control group, and the fuel injection amount control map in the selected control group is set to the selected fuel injection amount control. It is assumed that the map is _MS . After the internal combustion engine 1 starts, feedback correction is performed as appropriate based on the output of the oxygen sensor 12, and if a control group is determined to be inappropriate, the adjacent control group in the direction to correct the map deviation is adjusted as necessary. Accordingly, the fuel injection amount control map in that control group is set as the selected fuel injection amount control map _MS , and the fuel injection amount of the internal combustion engine 1 is controlled.

In step S6, if it is determined that the rotation speed Ne of the internal combustion engine is not greater than or equal to the predetermined rotation speed Ne ₁ after a predetermined period of time has passed since the starting motor of the internal combustion engine 1 is turned on, that is, Ne is smaller than Ne ₁ , then the internal combustion Engine 1 is determined to have a starting failure. It is determined that the current selected fuel injection amount control map _MS is not appropriate, and the process proceeds to step S8, where the selected fuel injection amount control map _MS is changed.

In step S8, the current selected fuel injection amount control map _MS , that is, the selected fuel injection amount control map _MS selected at the time of starting the internal combustion engine, is changed. As shown in FIGS. 4 to 7, the selected fuel injection amount control map M _S is added to the selected fuel injection amount control map M _S of adjacent fuel injection amount control maps M _S+1 and M _S−1 in the order of map numbers. Furthermore, the map is changed to the adjacent fuel injection amount control maps M _S+2 and M _S-2 .
That is, when the selected fuel injection amount control map M _S is the first fuel injection amount control map M ₁ , it goes to the third fuel injection amount control map M ₃ , and when it is the second fuel injection amount control map M _{2 , it goes to the fourth fuel injection amount control map M 2} . to the control map _M4 ; when the third fuel injection amount control map _M3 , to the first fuel injection amount control map _M1 ; when the fourth fuel injection amount control map _M4 , to the second fuel injection amount control map _M2 ; Change each.

The fuel injection amount control maps M ₁ , M ₂ , M ₃ , and M ₄ are adjacent fuel injection amount control maps M _S+1 in the map number order of the selected fuel injection amount control map M _S selected based on the alcohol concentration of the fuel. , M _S-1 is also configured so that the internal combustion engine 1 can be started based on the alcohol concentration of the fuel, so that the alcohol concentration of the fuel supplied to the internal combustion engine 1 is determined by the selected fuel injection amount control map M. Even if the fuel injection amount control maps M _S+1 and M _S-1 adjacent to _S are within the selected alcohol concentration range, the internal combustion engine 1 cannot be started in the fuel injection amount control maps M _S+2 and M _S-2. Guaranteed.

In step 9, similarly to step 6, the rotation speed Ne of the internal combustion engine 1 after a predetermined time has elapsed since the starting motor of the internal combustion engine 1 is turned on is compared with a predetermined rotation speed _Ne1 . If it is determined in step S9 that Ne is equal to or greater than Ne ₁ , it is determined that the internal combustion engine 1 has been started, and the process proceeds to step S7.

In step 9, the rotation speed Ne of the internal combustion engine 1 after a predetermined time has elapsed since the starting motor of the internal combustion engine 1 is turned on is compared with a predetermined rotation speed Ne ₁ , and Ne is smaller than Ne ₁ . If it is determined that the internal combustion engine 1 could not be started, a warning display device installed in the vehicle displays a warning that the internal combustion engine could not be started.

Since the fuel injection control device 20 for an internal combustion engine according to the embodiment of the present invention is configured as described above, it has the following effects.

The fuel injection control device 20 for an internal combustion engine according to the embodiment of the present invention is used in an internal combustion engine 1 that can use alcohol, gasoline, or a mixed fuel of alcohol and gasoline as fuel, and any of the fuels is stored. a fuel tank 5 in which fuel is stored, a fuel injection device 7 that supplies the fuel stored in the fuel tank 5 to the internal combustion engine 1, and an internal combustion engine that controls the fuel injection amount of the fuel injection device 7 according to the alcohol concentration of the fuel. This is a fuel injection control device. Furthermore, it has four fuel injection amount control maps that control the fuel injection amount of the internal combustion engine 1 according to the range of alcohol concentration of the fuel, including a first fuel injection amount control map M ₁ and a second fuel injection amount control map. _M2 , a third fuel injection amount control map _M3 , and a fourth fuel injection amount control map _M4 . Furthermore, these first fuel injection amount control map M ₁ , second fuel injection amount control map M ₂ , third fuel injection amount control map M ₃ , and fourth fuel injection amount control map M ₄ are based on the alcohol concentration of the fuel. The internal combustion engine 1 is configured to be able to start based on the alcohol concentration of the fuel in the adjacent fuel injection amount control maps M _{S +1} and M _S-1 in the map number order of the selected fuel injection amount control map M S selected based on the map number. has been done. When the internal combustion engine 1 is stopped, the immediately before stop fuel injection amount control map _Mx immediately before the stop of the internal combustion engine 1 is stored, and when the internal combustion engine 1 is started, the immediately before stop fuel injection amount control map _Mx is selected for fuel injection amount control. The starting of the internal combustion engine 1 is started with the fuel injection amount based on the selected fuel injection amount control map M _S , and if _it is determined that the internal combustion engine 1 has a starting failure, the selected fuel injection amount control map M _S to the fuel injection amount control maps M _{S +2} and M _S-2 which are further adjacent to the adjacent fuel injection amount control maps M S ₊₁ and M _{S-1 in the map number order of the selected fuel injection amount control map M S} , This is a fuel injection control device 20 for an internal combustion engine, which is characterized in that it starts the startup of the internal combustion engine 1.

According to the above configuration, when the internal combustion engine 1 cannot be started, adjacent fuel injection amount control maps M _S + ₁ , M in the map number order of the fuel injection amount control maps M S stored when the internal combustion engine 1 was stopped immediately before are used. Rather than selecting _S-1 as the selected fuel injection amount control map M _S , the fuel injection amount control map M _S+1 adjacent to the stored fuel injection amount control map M _S and the fuel injection amount further adjacent to M _S-1 are selected. Since the control maps M _S+2 and M _S-2 are selected as the selected fuel injection amount control map M _S , the internal combustion engine 1 can be started without selecting the fuel injection amount control map multiple times, so the internal combustion engine 1 can be started in a short time. It is possible to reduce battery consumption when starting the internal combustion engine 1 by deriving the fuel injection amount that can start the engine 1 and improving the ignition performance when starting the internal combustion engine 1 to improve the startability. can.

Furthermore, the fuel injection amount control maps include a first fuel injection amount control map M ₁ , a second fuel injection amount control map M ₂ , a third fuel injection amount control map M ₃ , and a fourth fuel injection amount control map M ₄ . If the internal combustion engine 1 fails to start within a predetermined time due to the above, fuel injection is controlled based on the fuel control map skipped by one in the map number order, so the fuel control map can be changed at once. Since the internal combustion engine 1 can be started with only the above-mentioned steps, the startability of the internal combustion engine 1 can be further improved.

The combustion injection control device for an internal combustion engine according to the present embodiment has four fuel injection amount control maps, but if it has five or more, the fuel injection amount control maps are switched as follows.
If the internal combustion engine 1 cannot be started in the initially selected fuel injection amount control map, the fuel injection amount control map is skipped by one in the direction of increasing or decreasing numbers in the map number order. Switch to quantity control map. In this state, turn on the starting motor of internal combustion engine 1 and start cranking. If internal combustion engine 1 cannot be started, select a fuel injection amount control map skipped one level in the same direction and turn on the starting motor. Turn it on and start cranking.
If the internal combustion engine 1 does not start even after repeating this and there are no more fuel injection amount control maps to select in the same direction, return to the initially selected fuel injection amount control map and select the map in order of map number. Switch to the fuel injection amount control map that skips one level in the opposite direction from the initially selected direction, turn on the starting motor of internal combustion engine 1 and start cranking, and if internal combustion engine 1 cannot start, Select the fuel injection amount control map that skips one in the same direction, turn on the starting motor, and perform cranking.
If the internal combustion engine 1 cannot be started even if the fuel injection amount control map is switched in the direction of increasing and decreasing numbers in the order of the map numbers, the warning display device installed in the vehicle A warning message is displayed indicating that the internal combustion engine could not be started.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the gist of the invention. , vehicles, internal combustion engines, etc., of course, include those implemented in various ways.

1... Internal combustion engine, 5... Fuel tank, 7... Fuel injection device, M1... First fuel injection amount control map, _M2 ... _Second fuel injection amount control map, _M3 ... Third fuel injection amount control map, M ₄ ...Fourth fuel injection amount control map.

Claims (2)

Used in internal combustion engines (1) that can use either alcohol, gasoline, or a mixed fuel of alcohol and gasoline as fuel,
a fuel tank (5) in which any of the fuels is stored;
a fuel injection device (7) that supplies the fuel stored in the fuel tank (5) to the internal combustion engine (1);
A fuel injection control device for an internal combustion engine that controls the fuel injection amount of the fuel injection device (7) according to the alcohol concentration of the fuel,
having three or more fuel injection amount control maps (M ₁ , M ₂ , M ₃ , M ₄ ) that control the fuel injection amount of the internal combustion engine (1) according to the range of alcohol concentration of the fuel;
The plurality of fuel injection amount control maps (M ₁ , M ₂ , M ₃ , M ₄ ) are sequentially assigned map numbers from the lowest alcohol concentration to the highest alcohol concentration, and
The plurality of fuel injection amount control maps (M ₁ , M ₂ , M ₃ , M ₄ ) are arranged in the map number order of the selected fuel injection amount control map (M _S ) selected based on the alcohol concentration of the fuel. Adjacent fuel injection amount control maps (M _S+1 , M _S-1 ) are configured such that the internal combustion engine (1) can be started based on the alcohol concentration of the fuel,
When the internal combustion engine (1) is stopped, a fuel injection amount control map (M _x ) immediately before the stop of the internal combustion engine (1) is stored;
When the internal combustion engine (1) is started, the fuel injection amount control map (M _x ) just before stopping is set as the selected fuel injection amount control map (M _S );
Starting the internal combustion engine (1) with a fuel injection amount based on the selected fuel injection amount control map (M _S );
When it is determined that the internal combustion engine (1) has a starting failure, the selected fuel injection amount control map (M _s ) is changed to the adjacent fuel in the order of the map number of the selected fuel injection amount control map (M _S ). The injection amount control map (M _S+1 , M _S-1 ) is switched to the adjacent fuel injection amount control map (M _S+2 , M _S-2 ), and starting of the internal combustion engine (1) is started. A fuel injection control device for an internal combustion engine, characterized in that: The fuel injection control device for an internal combustion engine according to claim 1, wherein there are four fuel injection amount control maps (M ₁ , M ₂ , M ₃ , M ₄ ).

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