BRPI0909364B1 - MULTI-FUEL ENGINE FUEL INJECTION CONTROL DEVICE - Google Patents

Abstract

Multi-fuel engine fuel injection control device. The present invention relates to a fuel injection control device of a multi-fuel engine that can properly regulate a fuel injection amount by responding rapidly to a change in fuel alcohol concentration. an oxygen concentration coefficient calculation part 100 calculates a verified mean value k02ref of an oxygen concentration coefficient k02 based on a measured value v02 of sensor 02 15. a first map change part 101 compares the verified measured value k02ref and a fuel injection map that is currently being referenced, and changes the fuel injection map to a high concentration side or a low concentration side when the present fuel injection map does not match the average value. verified k02ref. a second map change part 102 compares a measured value v02 and a fuel injection map, and changes the fuel injection map when the present fuel injection map does not correspond with the measured value v02. a shift selection part 104 selects both of the first and second map shift parts 101, 102 based on an engine load. The selected map change portion performs the map change based on a measured value v02 or the verified mean value k02ref.

Description

Invention Patent Descriptive Report for MULTI-FUEL ENGINE FUEL INJECTION CONTROL DEVICE.

TECHNICAL FIELD [001] The present invention relates to a multi-fuel injection control device, and more particularly a fuel injection control device suitable for a multi-fuel engine that can use a fuel mixed with gasoline and alcohol.

BACKGROUND OF THE TECHNIQUE [002] Recently, from an environmental protection point of view as a substitute for fossil fuels, a fuel alcohol is considered a promising fuel, and a vehicle that is able to move using a fuel mixed with alcohol , which is produced by mixing alcohol and gasoline in addition to gasoline (FFV: Flexible Fuel Vehicle) was developed.

[003] Fuel mixed with alcohol differs from fuel consisting of 100% gasoline with respect to a caloric value and an evaporation characteristic and, at the same time, fuels mixed with alcohol differ from each other in characteristics also dependent on concentration of alcohol indicative of an alcohol mixing rate with respect to gasoline. Consequently, when a fuel mixed with alcohol is used in an engine that provides for the use of fuel consisting of 100% gasoline, an air / fuel control ratio is outside a theoretical air / fuel ratio and therefore can be a case in which the contents of an exhaustion are changed or the ability to drive is changed as a result. To overcome these technical drawbacks, patent document 1 describes a technique that performs a correction, increasing an amount of fuel injection

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2/25 that corresponds to the alcohol concentration of the fuel to obtain the same equivalence ratio.

[004] Patent Document 1: JP-A-2004-293491

SUMMARY OF THE INVENTION

Technical Problem [005] However, in FFV, the alcohol concentration of the fuel to be fed into an engine is not always the same, and there may be a case where the alcohol concentration differs for each fuel feeding operation. When the alcohol concentration of the fuel fed during a period when an engine is stopped differs enormously from a stored stored result, that is, the alcohol concentration of the fuel in a fuel tank, there is a possibility that an injection amount of fuel falls from an appropriate range at the time of restarting the engine.

[006] Additionally, in a conventional feedback control that increases or decreases an amount of fuel injection based on an oxygen concentration detection result, a correction coefficient is obtained by applying a measured value (voltage) from an O2 sensor for a predetermined function, a verified average value (for example, a moving average value) is calculated from the correction coefficients obtained during a predetermined period, and feedback control is performed using the verified average value as an input parameter. Consequently, even when the oxygen concentration in an exhaust gas is changed, a predetermined response delay occurs before such a change is reflected in the increase or decrease in the amount of fuel injection.

[007] Here, alcohol contains oxygen atoms in its composition, and an amount of oxygen per volume unit nePetição 870180046933, from 06/01/2018, p. 6/35

3/25 necessary to burn alcohol is small compared to a case where gasoline is burned and, therefore, to obtain the same equivalence ratio, a higher concentration of alcohol is necessary to increase the amount of fuel injection. Consequently, when fuel with low alcohol concentration is fed with the stored stored result of high alcohol concentration, fuel that exceeds an appropriate amount is fed giving rise to an inconvenience that the air / fuel ratio becomes excessively rich thereby generating misfire.

[008] It is an objective of the present invention to provide a fuel injection control device for a multi-fuel engine that can optimize a quantity of fuel injection by responding quickly to a change in fuel alcohol concentration.

Problem Solution [009] To achieve the aforementioned objective, the present invention is characterized by providing the following means in a fuel injection control device that performs a control of an amount of fuel injection of fuel mixed with alcohol in a engine based on the concentration of oxygen in an exhaust gas.

(1) A fuel injection control device for a multi-fuel engine of the present invention is characterized by including: an oxygen concentration sensor that is configured to emit a signal in response to the concentration of oxygen in the exhaust gas; various fuel injection maps that are provided for each of the alcohol concentrations in the fuel and are configured to determine a relationship between an engine's operating state and the amount of fuel injection; a medium that is configured to calculate the oxygen concentration by checking

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4/25 an oxygen concentration sensor output for a predetermined period; a first means of change that is configured to change the fuel injection map based on the oxygen concentration; a second switching means that is configured to change the fuel injection map based on the oxygen concentration sensor output; a selection means that is configured to select each of the first and second means of change based on a state of charge of the motor; and a fuel injection quantity determination means that is configured to determine a fuel injection quantity by applying the operating state of the engine to the fuel injection map which is changed by the selected change medium.

(2) The fuel injection control device of a multi-fuel engine of the present invention is characterized by the fact that the second means of change is configured to change the fuel injection map based on a signal emitted by the fuel concentration sensor. oxygen.

(3) The fuel injection control device of a multi-fuel engine of the present invention is characterized by the fact that the second means of change is configured to change the fuel injection map when the throttle opening is determined at a value greater than a predetermined reference value.

(4) The fuel injection control device of a multi-fuel engine of the present invention is characterized by the fact that the second means of change is configured to change the fuel injection map to a fuel injection map on one side higher alcohol concentration when the oxygen concentration in the exhaust gas is high.

Advantageous Effects of the Invention

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5/25 [0010] According to the present invention, it is possible to obtain the following advantageous effects.

(1) According to the invention required in claim 1, when the engine is in a state of high load and it is necessary to quickly control the amount of fuel injection based on an air / fuel ratio, a feedback control is carried out, instead of using the oxygen concentration check based on an oxygen concentration sensor output as an input parameter, use an oxygen concentration sensor output as the input parameter and therefore a change in the air ratio / fuel can be quickly reflected in the amount of fuel injection.

(2) According to the invention required in claim 2, since the control is performed based on the sensor's output signal, faster control can be performed.

(3) According to the invention required in claim 3, the fuel injection map is changed when the throttle opening is greater than the predetermined set point and the engine load is greater and, therefore, a state of high load of the engine can be quickly eliminated and, in addition, an adverse effect on a catalyst or similar can be alleviated due to the cooling of the fuel for the engine.

(4) According to the invention required in claim 4, in the feedback control that uses the oxygen concentration sensor output as the input parameter, only a control switching from the fuel injection map to the fuel injection map fuel on the higher alcohol concentration side and performed in a poor state, where the air / fuel ratio is high, and a change control from the fuel injection map to the fuel injection map on the alcohol concentration side me

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6/25 nor is performed even in a rich state, where the air / fuel ratio is low. Consequently, it is possible to prevent a control, which performs a correction to increase the amount of fuel injection, from being carried out based on the output of the oxygen concentration sensor in a state where the influence of noise and disturbances at the outlet is not relieved.

DESCRIPTION OF MODALITIES [0011] A better way of carrying out the present invention is applied in detail hereinafter in conjunction with the drawings. Figure 1 is a view showing the total constitution of an internal combustion engine and a fuel injection control system of the internal combustion engine according to an embodiment of the present invention.

[0012] An intake pipe 2 and an exhaust pipe 7 are connected to an engine 1, and an air filter 3 is provided on one side upstream of the intake pipe 2. An amount of intake air in engine 1 is regulated by a butterfly valve 4 arranged inside the intake pipe 2. The opening of the butterfly valve 4 is detected by a butterfly opening sensor 11 (hereinafter expressed as a TH sensor).

[0013] An inlet tube absolute pressure sensor 12 (hereinafter expressed as a PBA sensor) measures an PBA inlet tube absolute pressure. An inlet temperature sensor 16 (hereinafter expressed as a TA sensor) measures an inlet temperature TA in the intake pipe 2. A water temperature sensor 13 (hereinafter expressed as a TW sensor) measures a temperature engine cooling water TW 1. A crank angle sensor 14 (hereinafter expressed as a CRK sensor) measures a CRK crank angle indicative of a crank position of the engine 1.

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7/25 [0014] A three-way catalyst 8 is provided on one side downstream of the exhaust pipe 7, and an oxygen concentration sensor 15 (hereinafter expressed as an O2 sensor) that measures the oxygen concentration of an exhaust gas in the exhaust pipe 7 is disposed between the engine 1 of the exhaust pipe 7 and the three-way catalyst 8. An engine control device (ECU: Electronic Control Unit) 10 performs several engine controls including one fuel injection control based on detection signals emitted from the respective sensors mentioned above. An injector 5 is opened in response to an injection control signal from ECU 10, and injects gasoline or a mixed fuel consisting of gasoline and alcohol (ethanol in this mode).

[0015] Figure 2 is a functional block diagram showing the constitution of the main parts of ECU 10 mentioned above. In the drawing, the same symbols indicate parts identical or similar to the parts mentioned above. Here, constitutions that are unnecessary for the explanation of the present invention are not shown in the drawing.

[0016] ECU 10 includes, as its main components, a CPU 21, a RAM 22 that provides a working area on CPU 21, a ROM 23 in which programs executed by CPU 21 and information for an injection control (a Pb / Ne map, Ne / TH map, various correction coefficient tables, starting control and similar information described later) are stored in a non-volatile manner, and an EEP-ROM 24 in which various control parameters including sets predetermined methods described later are stored in a rewritable and non-volatile manner. CPU 21 and various memory elements 22, 23, 24 are connected to each other by an internal bus.

[0017] Figure 3 is a view that shows schematically a

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8/25 ROM memory contents mentioned above 23. In this mode, ROM 23 stores the Pb / Ne map, the Ne / TH map, the various correction coefficient tables and the start control information in a mutually correlated way for each concentration of ethanol in the fuel.

[0018] As described above, ethanol has oxygen atoms in the composition and therefore the amount of oxygen per unit volume needed to burn ethanol is small compared to a case where gasoline is burned, whereby when a fuel mixed with ethanol and gasoline is used, a theoretical air / fuel ratio becomes lower compared to a case where a fuel consisting only of gasoline is used. Consequently, to operate engine 1 in an optimal state, it is necessary to determine the injection control information for each mixing ratio between ethanol and gasoline.

[0019] On the other hand, it was found that from the results of experiments or the like that when ethanol has a certain level of concentration, even when a map or table to drive engine 1 in an optimal state is applied to another concentration within a fixed range, it is possible to carry out a control substantially the same as a control that is carried out by providing a map or an appropriate table for another concentration.

[0020] Consequently, in this modality, as in an example shown in figure 4, variations in ethanol concentration are determined, and four types of ethanol concentrations E1, E2, E3, E4 (the order of alcohol concentration being E1 <E2 <E3 <E4) are preliminarily determined as the reference concentrations of ethanol in the respective regions, and a Pb / Ne map, a Ne / TH map, various correction coefficient tables and starting control information are preferred for each concentration of reference.

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9/25 [0021] Here, the number of reference concentrations can be three or more, and reference concentrations can be appropriately allocated in concentrations ranging from 0% to 100%. In addition, the respective maps and tables are, as shown in figure 4, configured to have certain ranges within which the concentrations overlap.

[0022] In this modality, a set of the Pb / Ne map, the Ne / TH map, the various correction coefficient tables and the starting injection information that is prepared for each ethanol reference concentration can be expressed as a The map set and the map sets of the respective ethanol reference concentrations can be expressed as a map set E1, a map set E2, a map set E3, and a map set E4 respectively.

[0023] In such a constitution, the calculation processing of a quantity of injection fuel by ECU 10 is roughly classified into a starting injection control and a normal operating injection control.

[0024] In start injection control, a TICR start injection time in which fuel is injected by injector 5 when starting the engine is determined univocally based on a TW water temperature of the cooling water for the engine 1. To be more specific as exemplified in an example shown in figure 5, the corresponding relationship between the TW water temperature and the TICR start injection time is preliminarily stored as the start injection table in ROM 23, and the time Starting injection TICR is obtained by referencing the starting injection table based on the TW water temperature detected when starting the engine.

[0025] This TICR start injection time, as shown in

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10/25 figure 6A, differs in an optimal injection time for each ethanol concentration even when the TW water temperature is fixed and, therefore, to maintain a favorable starting performance, it is necessary to determine the injection time such that the injection Excessive fuel consumption can be prevented when the ethanol concentration is in a lower limit fuel concentration and, at the same time, maximum injection can be performed when the ethanol concentration is in an upper limit ethanol concentration. For this purpose, in this modality, the concentration ranges are determined as exemplified in an example shown in figure 6B, in which the starting injection table is prepared for each reference concentration E1, E2, E3 or E4 of ethanol.

[0026] Additionally, in these starting injection tables, when constant, a width of increment Dti of the starting injection time, the number of repetitions N indicative of the number that becomes a reference to determine the number of injections that allow to increase the injection time by the aforementioned increment width, and a maximum limit Tmax of the start injection time are correlated with each other. Values of these constants are also preliminarily stored in ROM 23 in this mode. From here on, the start injection information can be expressed in a way that the start injection information includes a start injection table and these constants.

[0027] On the other hand, in the control of injection of normal operation, an amount of intake air under various conditions can be obtained by referencing the Pb / Ne map or the Ne / TH map that is preliminarily obtained based on results of experiments or similar . A basic fuel injection time TIM is calculated based on the amount of injection air and a target air / fuel ratio. Figure 7A is a view showing an example of the Pb / Ne map, and figure 870180046933, of 6/1/2018, p. 14/35

11/25 ra 7B is a view showing an example of the Ne / TH map.

[0028] The Pb / Ne map mentioned above is a map used in a method of estimating the amount of incoming oxygen that is adopted when performing a low load operation such as idling and is referred to as a density density method. velocity. A quantity of intake air is obtained based on an absolute pressure of the PBA intake pipe and a rotational speed of the engine Ne by reference to the map. As shown in figure 7A, the fixed correlation is not established between the absolute pressure of the PBA intake pipe and the rotational speed of the engine Ne, and the intake air quantity is specified as a diagram of equal air quantity.

[0029] Additionally, the Ne / TH map is a map used in a method of estimating an amount of incoming oxygen that is referred to as a butterfly velocity method adopted at the time of high load operation, in which the amount of air from admission is obtained based on a rotational speed of the engine Ne and the throttle opening TH by reference to the map. As shown in figure 7B, also on the Ne / TH map, in the same way as the Pb / Ne map, the fixed correlation is not established between the rotational speed of the Ne engine and the TH butterfly flap, and the amount of intake air is specified as a diagram of equal air quantity.

[0030] Also with respect to the Ne / TH map and the Pb / Ne map, an amount of intake air differs from each concentration of ethanol and, therefore, to maintain a favorable starting performance, in this modality, the Ne / TH map and the Pb / Ne map are prepared for each reference concentration (E1, E2, E3 and E4) of ethanol.

[0031] Additionally, in the injection control of normal operation, when the TIM fuel injection time is calculated based on the amount of intake air obtained from the Pb / Ne map

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12/25 or from the Ne / TH map, as a next step, correction based on the difference in an environmental condition between an experimental state and an actual operating state of motor 1 is performed.

[0032] Figure 8 is a view showing an example of the correction coefficient table to obtain an input temperature correction coefficient KTA that corresponds with a TA intake air temperature obtained based on a measurement result from the TA sensor 16. As the correction coefficients, in addition to the input temperature correction coefficient KTA, the correction coefficients based on the measured values that are respectively obtained by a TH 11 sensor, a TW 13 sensor, a CKR 14 sensor and an O2 sensor 15 are used. To be more specific, there is a post-start increment correction coefficient KAST, a KTW water temperature correction coefficient, a TACC acceleration correction coefficient, a FICSTG ignition regulation coefficient and the like. In this modality, the correction coefficient tables are provided for these respective correction coefficients and the respective correction coefficient tables are provided for each reference concentration (E1, E2, E3, E4) of ethanol.

[0033] Then, the ignition regulation correction shown in figure 3 is explained by reference to figure 9A and figure 9B. An injection amount of fuel mixed with ethanol is increased compared to an injection amount of gasoline, while to compare fuels mixed with ethanol with each other, the higher the ethanol concentration of the fuel mixed with ethanol, the greater the injection amount of the fuel mixed with ethanol becomes. Consequently, when the fuel injection of the fuel mixed with ethanol starts at the regulation similar to the injection of gasoline as the fuel, the regulation of the end of the fuel injection mixed with ethanol is delayed.

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13/25 [0034] In view of the aforementioned fact, in this modality, the respective correction coefficients tables are provided for each reference concentration (E1, E2, E3, E4) of ethanol in order to advance the starting regulation of injection that corresponds to the ethanol concentration.

[0035] Figure 9A and figure 9B are comparison views, in which the ignition regulation and a fuel injection period having E1 ethanol concentration are compared with each other in figure 9A, and the injection regulation and a period fuel injection having ethanol concentration E4 are compared with each other in figure 9B. In this modality, the correction coefficient table is prepared for each reference concentration of ethanol such that the longer the injection period due to the increase in the concentration of ethanol, the more the ignition regulation is advanced, and the correction time is determined for each rotational speed of the NE motor in each correction coefficient table.

[0036] Next, an operation of the fuel injection control device of the engine of this modality is explained in detail together with figure 10 which is a functional block diagram and flowcharts shown in figure 11 to figure 15.

[0037] Figure 10 is a block diagram that functionally expresses the constitution of the fuel injection control device of the present invention, where the symbols equal to the symbols used above indicate identical or similar parts.

[0038] An O2 concentration coefficient calculation part

100 calculates the KO2 oxygen concentration coefficient to maintain a theoretical air / fuel ratio based on a measured value (voltage) VO2 of the O2 sensor 15 indicative of the oxygen concentration in the exhaust tube 7. It is known that the coefficient of oxygen KO2 oxygen concentration has an approximately proportional ratio Petition 870180046933, of 6/1/2018, p. 17/35

14/25 final with the ethanol concentration of the fuel. In addition, the oxygen concentration coefficient KO2 fluctuates during an operation of engine 1 due to a change with time or external influences, and therefore the part of calculating the concentration coefficient of O2 100 also calculates a verified average value (moving average value ) KO2REF of the KO2 oxygen concentration coefficient based on the following formula (1), for example. Here, KO2REFn-1 is a previous time verified measured value. Here, the symbol β is an average coefficient and is usually determined at approximately 0.1.

Formula 1

KO2REFn = b-KO2 + (1-b) -KO2REFn-1 [0039] A first part of map change 101 compares the concentration of ethanol that corresponds with the average value verified above KO2REF and the reference concentration of the injection map of fuel that is currently being referenced, and when the fuel injection map present does not match the verified KO2REF average value, the fuel injection map is switched to a high concentration side or a low concentration side.

[0040] The average value checked KO2REF displays a large value when the oxygen concentration in an exhaust gas is high, and displays a low value when the oxygen concentration is low. Consequently, when the measured measured value KO2REF is large, it is determined that the ethanol concentration of the fuel is high and processing to change the fuel injection map to the fuel injection map with the high ethanol concentration is carried out. On the contrary, when the average KO2REF value is small, it is determined that the ethanol concentration of the fuel is low and the change processing of the injection map 870180046933, from 06/01/2018, p. 18/35

15/25 fuel injection for the fuel injection map with low ethanol concentration is carried out.

[0041] A second part of map change 102 compares a measured value VO2 of the aforementioned O2 sense 15 with a predetermined reference value VO2ref, and changes the fuel injection map to the fuel injection map on one side of higher ethanol concentration when the measured value VO2 is below the reference value VO2 ref.

[0042] A motor load detection part 103 detects a motor load present based on a rotational speed of the motor Ne and throttle opening TH. A shift selection part 104 selects one of the first and second map shift parts 101, 102 based on a determination result on the aforementioned motor load. The map change part selected performs the map change based on the measured value VO2 of the O2 sensor 15 or the average verified value KO2REF of the O2 sensor

15. A fuel injection quantity control part 105 decides a fuel injection quantity by applying an engine parameter and a fuel injection map changed by the selected map change part.

[0043] Figure 11 is a main flow of the fuel injection control and is executed repeatedly in a predetermined cycle after turning a main switch (SW). In this mode, when electricity is supplied to ECU 10 by turning the SW and a fuel injection control program for CPU 21 is started, a start injection control is performed in step S1.

[0044] Figure 12 is a flowchart showing the steps of starting injection control. In step S101, a predetermined set registered on an EEP-ROM 24 is read. This predetermined set is given for the start injection control stored in the

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16/25 time to perform a previous time operation and is described in detail later together with a flowchart shown in figure 15. In step S102, the starting injection information is extracted from the predetermined set read, and the injection time of start TICR which is an initial value of the start injection time is obtained based on the start injection table contained in the start injection information and a TW cooling water temperature detected by the TW 13 sensor. Additionally, the increment width Dti, the repetition number N and the upper limit of the starting injection Tmax that are contained in the starting injection information are also extracted. In addition, the starting injection number n is reset.

[0045] In step S103, it is determined whether or not the engine is dragging. When the engine is not dragged, the determination is continued until the drag is started. After that, when it is determined that the engine is dragging, processing proceeds to step S104, and the starting injection number n is increased.

[0046] In step S105, the start injection time TICR and the upper limit of start injection Tmax are compared with each other. When the TICR start injection time is below the upper limit of the Tmax start injection time, processing proceeds to step S106. In step S106, the number of starting injection n is compared with the number of repetition N. When the number n of starting injection is equal to the number of repetition N, processing proceeds to step S107. In step S107, a Dti increment width is added to the TICR start injection time in order to determine a new TICR start injection time. In step S108, the starting injection number n is reset. In step S109, the rotational speed of the present motor (Ne) that is calculated

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17/25 based on the measured value of the CKR 14 sensor is compared with the reference rotational speed A for starting determination. When the rotational speed of the motor (Ne) exceeds the rotational speed of reference A, it is determined that the start is completed and processing ends.

[0047] On the contrary, when it is determined that the rotational speed of the motor present Ne is equal to or less than the rotational speed of reference A and the motor is starting, the processing returns to step S103. In addition, when it is determined that the TICR start injection time is not less than the upper injection time limit Tmax in step S105 and it is determined that the number n of the start injection is not equal to the repetition number N in step S106 , processing proceeds to step S109 while maintaining the present TICR start injection time and determination of start completion is performed in step S109.

[0048] Figure 16 is a view showing a change in the TICR start injection time when the repeat number N is 4 in the processing shown in figure 12. Each time the fuel injection is performed 4 times, the injection time starting time is increased in a staggered manner by Dti, and when a cumulative starting injection time reaches the upper limit of starting injection time Tmax, the drag is continued in a state that the starting TICR injection time is maintained . Here, Dti and the repetition number N are decided preliminarily such that a minimum value in which the TICR start injection time is changed becomes a minimum demand injection amount (lower limit concentration demand injection amount) of reference concentration of ethanol determined in the predetermined set, and a maximum value at which the TICR start injection time is changed becomes a maximum demand injection quantity (amount of

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18/25 injection of upper limit concentration demand) into the ethanol concentration.

[0049] Due to such processing, even when ethanol or gasoline is refilled at the time of stopping the engine, a fuel mixture ratio remaining in a fuel pipe is in a state before refueling is carried out. Consequently, by performing the start control using the fuel injection map that corresponds to the reference ethanol concentration in the usual operating time just before the main SW is stopped, it is possible to perform a quick start control in an appropriate state while avoiding the vaporization of the engine spark plug 1.

[0050] Additionally, in the processing shown in figure 12, the TICR start injection time is increased by the increment width Dti each time the start injection number n reaches the repetition number N and, therefore, it is possible to perform the start control gradually increasing the fuel injection time, that is, gradually increasing the amount of fuel injected from the injector 5 until the engine 1 starts is completed.

[0051] Returning to figure 11, when the start injection control is completed in the aforementioned manner, processing proceeds to step S2 in the main flow, and the usual operation injection control is performed. Figure 13 shows a flowchart showing the steps of the usual operation injection control. In step S201, the map change is performed in order to select the optimal fuel injection map for the ethanol concentration of the fuel. That is, when a map to calculate the optimum amount of basic TIM injection for the present state of the engine, either from map E1, map E2, map E3 and map E4 is selected.

[0052] Figure 14 is a flowchart showing the stages of change 870180046933, from 01/06/2018, p. 22/35

19/25 map dance. In step S11, a rotational speed of the motor (Ne) is calculated based on a detection signal from the CRK sensor

14. In step S12, it is determined whether the throttle opening (TH) obtained based on the calculated rotational speed of the motor (Ne) and a detection signal from the TH 11 sensor is or is not within a usual load region (a region map change based on the average verified value KO2REF) shown in figure 17.

[0053] When the throttle opening (TH) is within the usual load region, processing proceeds to step S13, and it is determined whether or not motor 1 is in a finished idle state, ie whether motor 1 is whether or not in the normal operating state based on a TW temperature obtained based on a detection signal from the TA sensor 16. When it is determined that engine 1 is not in a finished idle state, changing the fuel injection map is not performed and processing is finished.

[0054] When it is determined that the engine 1 is in a finished idle state, processing proceeds to step S14 in which the calculation of the aforementioned moving average of the formula (1) is carried out with respect to the obtained KO2 oxygen concentration coefficient based on a measured value VO2 of the O2 sensor 15 in order to calculate the verified average value KO2REF, and the calculated result is updated and recorded as a new verified average value KO2REF. [0055] In step S15, it is determined whether the updated verified average value KO2REF is within a range defined by the limit values in the reference concentration of the present ethanol. Here, as exemplified by an example shown in figure 18, the limit values at the reference concentration mean an upper limit limit value and a lower limit limit value which are determined for each reference concentration. The limit values are adjusted and determined such that the respective maps overlap. For example,

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20/25 as shown in figure 18, in the case of map E1, the lower limit limit value is 0 and the upper limit limit value is 1.2. In the case of the E2 map, the lower limit limit value is 0.8 and the upper limit limit value is 1.2. In the case of the E3 map, the lower limit limit value is 0.8 and the upper limit limit value is 1.2. In the case of the E4 map, only the lower limit limit value is determined and the lower limit limit value is 0.8.

[0056] For example, with the current reference concentration being determined in E2, when the verified average value KO2REF is within a range of 0.8 and 1.2, it is determined that the verified average value KO2REF is within a range defined by the limit values, and the map change is not performed. On the contrary, when it is determined that the verified average KO2REF value is below 0.8, processing proceeds to step S16 and the change to map E1 is carried out. In addition, when it is determined that the verified average KO2REF value exceeds 1.2, processing also proceeds to step S16 in the same way and the change to the E3 map is performed.

[0057] On the other hand, when it is determined that NE / TH is outside the KO2 control region in the above mentioned step S12, processing proceeds to step S17. In step S17, it is determined whether or not NE / TH is within a high load region (VO2-based map change region). When NE / TH is outside the high load region, processing is completed without changing the fuel injection map.

[0058] On the contrary, when NE / TH is within the high load region, processing moves to step S18, and it is determined whether the reference map present is E3 or E4. When the E3 map or more is already referenced, processing is completed without changing the fuel injection map. Instead,

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21/25 when it is determined that the present reference map is smaller than E3, processing proceeds to step S19.

[0059] In step S19, it is determined whether the measured value VO2 of the O2 sensor 15 is or not equal to or less than the reference voltage VO2ref. In this mode, when it is determined that the measured value VO2 is not equal to or less than 0.2 V, the processing is finished without changing the fuel injection map. Conversely, when it is determined that the measured value VO2 is equal to or less than 0.2 V, an excessively poor state is determined and the process proceeds to step S20, and the fuel injection map is changed to a map in a larger E side compared to the present map. That is, when the reference concentration present is E2, the fuel injection map is changed to the E3 map.

[0060] Returning to figure 13, when the map change in step S201 is completed, processing advances to step S202. In step S202, using the set of maps decided in the manner mentioned above, the basic fuel injection time TIM is calculated using the engine rotational speed Ne and the intake air pressure Pb as engine parameters. In step S203, the measured values obtained by the respective sensors such as the TH 11 sensor, the TW 13 sensor, the CRK 14 sensor and the O2 sensor 15 are applied to corresponding tables in the map set in order to calculate the correction coefficients such as a post-start increment correction coefficient (KAST), a water temperature correction coefficient (KTW), an acceleration correction coefficient (TACC) or similar. In step S204, the amount of TIM basic fuel injection mentioned above is multiplied or added to the respective correction coefficients in the same way as the related technique in order to calculate the injection time 870180046933, from 06/01/2018, p. 25/35

22/25 tion of fuel Tout after correction, and the final fuel injection amount (time) is decided taking an invalid injector 5 or similar time into account.

[0061] Returning to the main flow in figure 11, when the usual operation injection control in step S2 is completed in the manner mentioned above, the processing proceeds to step S3 in order to perform the start injection preparation processing.

[0062] Figure 15 is a flowchart showing the steps for processing the preparation of starting injection. In step S301, the oxygen concentration coefficient KO2 is calculated based on the measured value VO2 of the O2 sensor 15, and the oxygen concentration coefficient Ko2 is applied in the formula (1) mentioned above in order to calculate the average value verified KO2REF . In step S302, the fuel ethanol concentration is estimated based on the ethanol concentration and the verified average KO2REF value shown in figure 4, and any one of the E1 map, the E2 map, the E3 map and the E4 map is selected based on the estimated result.

[0063] In step S303, the map and the selected reference concentration as described above are updated and registered in EEPROM 24 as the predetermined set. Since the predetermined set is stored in a non-volatile manner, when the main SW is rotated again after the interruption of the main SW, the predetermined set is read again in step S101 of step S12 and is used in the next start injection control.

BRIEF DESCRIPTION OF THE DRAWINGS [0064] Figure 1 is a view showing an internal combustion engine and an engine fuel injection control system according to an embodiment of the present invention.

[0065] Figure 2 is a functional block diagram showing the constitution of a main part of an ECU.

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23/25 [0066] Figure 3 is a view schematically expressing the memory content of a ROM.

[0067] Figure 4 is a view showing an example of a method of determining an ethanol concentration range.

[0068] Figure 5 is a view showing an example of a starting injection table.

[0069] Figure 6A is a view showing a correlation between a TICR start injection time and fuel ethanol concentration.

[0070] Figure 6B is a view showing a correlation between a TICR start injection time and cooling water temperature.

[0071] Figure 7A is a view showing an example of a Pb / Ne map.

[0072] Figure 7B is a view showing an example of a Ne / TH map.

[0073] Figure 8 is a view showing an example of a correction coefficient table to obtain a KTA intake air temperature correction coefficient.

[0074] Figure 9A is a view to explain the injection adjustment correction.

[0075] Figure 9B is a view to explain the injection adjustment correction.

[0076] Figure 10 is a block diagram to functionally express the constitution of the fuel injection control device of the present invention.

[0077] Figure 11 is a view showing a main flow from a fuel injection control.

[0078] Figure 12 is a flowchart showing steps of a start injection control.

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24/25 [0079] Figure 13 is a flow chart showing steps of a usual operation injection control.

[0080] Figure 14 is a flow chart showing the steps to change the maps.

[0081] Figure 15 is a flowchart showing the processing steps for preparing the starting injection.

[0082] Figure 16 is a view showing a TICR change in the start control.

[0083] Figure 17 is a view showing a state that a control method differs depending on a motor's state of charge.

[0084] Figure 18 is a view to explain a map change processing when performing a usual operation.

[0085] Figure 19 is a view showing an example of a method of determining the map change.

Reference Listing

- motor

- intake pipe

- air filter

- butterfly valve

- injector

- exhaust pipe

- three-way catalyst

- engine control device

- butterfly opening sensor

- inlet tube absolute pressure sensor

- water temperature sensor

- crank angle sensor

- oxygen concentration sensor

- intake air temperature sensor

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25/25

- CPU

- RAM

- CPU

- EEP-ROM

Claims (4)

1. Fuel injection control device for a multi-fuel engine that is configured to control an injection amount of a fuel mixed with alcohol in an engine based on the concentration of oxygen in an exhaust gas, the fuel injection control device fuel comprising: an oxygen concentration sensor (15) that is configured to emit a signal in response to the concentration of oxygen in the exhaust gas; a plurality of fuel injection maps (E1, E2, E3, E4) that are provided for each alcohol concentration in the fuel and are configured to determine a relationship between an operating state of the engine and the amount of fuel injection; and a means (100) that is configured to calculate the oxygen concentration by checking an oxygen concentration sensor output for a predetermined period; characterized by the fact that it comprises: at least one first change means (101) which is configured to change the fuel injection map based on the oxygen concentration; at least a second change means (102) which is configured to change the fuel injection map based on the oxygen concentration sensor output; a selection means (104) which is configured to select any of the first and second means of change based on a state of charge of the motor; and a fuel injection quantity determination means (105) that is configured to determine a fuel injection quantity by applying the engine's operating status on the map Petition 870180165341, of 12/19/2018, p. 4/9 2/2 fuel injection that is changed by the selected change medium. 2. Fuel injection control device of a multi-fuel engine, according to claim 1, characterized by the fact that the second means of change (102) is configured to change the fuel injection map based on an emitted signal by the oxygen concentration sensor. 3. Fuel injection control device of a multi-fuel engine, according to claim 2, characterized by the fact that the second means of change (102) is configured to change the fuel injection map when the throttle opening is determined at a value greater than a predetermined reference value. 4. Fuel injection control device for a multi-fuel engine, according to claim 3, characterized by the fact that the second change medium (102) is configured to change the fuel injection map to an injection map of fuel on a side with higher alcohol concentration when the oxygen concentration in the exhaust gas is high.