JP5131059B2 - Engine fuel injection control method - Google Patents

Description

    The present invention relates to a fuel injection control method for an engine.

    In diesel engines, various injection modes (injection patterns) with different numbers of fuel injections in one cycle of the engine are combined to reduce NOx and soot in exhaust gas, reduce noise and vibration, improve fuel economy and torque, etc. Driving more and more. That is, the fuel injection control region based on the engine operating state is divided into, for example, a multi-stage injection region in which fuel is injected a plurality of times in one cycle and a normal injection region in which fuel is injected once in one cycle. Accordingly, the multi-stage injection and the normal injection are properly used. In such an engine, the fuel injection mode must be changed as appropriate in accordance with changes in the engine operating state (engine speed and required torque).

An example of fuel injection control when changing the fuel injection mode is described in Patent Document 1. That is, in the transition region between the multi-stage injection (multi-injection) region and the normal injection region, while performing multi-stage injection, the fuel pressure to be used for this transition region, fuel pressure control data used for the multi-stage injection region, Interpolation is performed using combustion pressure control data used in the normal injection region.
JP 2007-332812 A

    By the way, in the transition region when the fuel injection mode is changed from the first region to the second region, even if the injection mode in the first region is adopted, the fuel injection timing and the injection amount in the injection mode are adopted. It is necessary to decide separately. For this determination, a method of interpolating based on data (injection timing and injection amount) preset in each of the first and second regions is usually employed.

    FIG. 6 is an explanatory diagram for the interpolation. In the injection characteristic map in the upper column of the figure, the fuel injection control region based on the engine operating state (engine speed and required torque) includes the region in which the injection mode a is used, the region in which the injection mode b is used, and the injection mode c. It is divided into areas to be adopted. In the lower column of the figure, the transition region “NEII, torque when transitioning from“ NEII, torque D ”of injection mode b (three-stage injection) to“ NEII, torque E ”of injection mode c (two-stage injection) is shown. An example of interpolation between “DE” is shown.

    In this example, the intermediate injection data of the transient region “between NE II and torque D-E” is interpolated from the intermediate injection data of “NE II, torque D” and the previous injection data of “NE II, torque E”. However, since this interpolation data does not take into account the first stage injection of “NEII, torque D”, the injection amount and the injection timing cannot be required values, and the first stage of “NEII, torque D”. The first-stage injection in the transient region “between NE II and torque D-E” in which the injection is directly reflected cannot be the required value. Further, the injection timing of the post-stage injection data of the transient region “between NE II and torque D-E” interpolated from the post-stage injection of “NE II, torque D” and the post-stage injection of “NE II, torque E” becomes the required value. Don't be.

    Therefore, an object of the present invention is to perform fuel injection control that meets the performance requirements for the engine even in a transient region where the fuel injection mode is switched.

    With respect to such a problem, the present invention provides fuel injection based on data interpolated between data of the same injection mode even in a transitional region where the operation region of one fuel injection mode shifts to the operation region of another fuel injection mode. The control can be performed.

In the first aspect of the invention, the fuel injection control region based on the engine operating state is a first region where fuel injection by the fuel injection valve is performed in the first injection mode, and the fuel injection is different from the first injection mode. a second region takes place in two injection mode, the fuel injection and a third region which is performed at a different third jetting mode and the first jetting mode and a second jetting mode, the first region and the second there case next to the second region, the second adjoin and the region and the third region, a fuel injection control method for an engine which is not adjacent to the above first region and the third region,
A first injection characteristic map and a second injection characteristic map in which data relating to at least one of the fuel injection timing and the injection amount are respectively set;
The first injection characteristic map is used for interpolation of data in the first injection mode control data set in the first area and a transition area in the middle of transition from the first area to the second area. the interpolation data of the first jetting mode which is set in a part of the second region, the third and the control data of the third injection mode set in the region, the second region from the third region The third injection mode interpolation data set in a part of the second area, used for data interpolation in the transition area in the middle of
The second injection characteristic map is used for data interpolation in the transition region in the middle of transition from the second region to the third region, and the control data for the second injection mode set in the second region. The interpolation data of the second injection mode set in a part of the third region and the first region used for data interpolation in the transition region in the middle of transition from the second region to the first region. Data for interpolation of the second injection mode set in part,
When the engine operating state exists in each of the first to third regions, fuel injection control is performed using the control data in the first or second injection characteristic map in which the control data for the region is set. Done
Whenever the engine operating state shifts between the first to third adjacent regions, the first injection characteristic map and the second injection characteristic map are alternately switched, and the control data set in the transfer destination region is obtained. To control fuel injection,
In the transition region in the middle of the transition, the control data of the first or second injection characteristic map in which the control data of the transition source region is set and a part of the transition destination region of the injection characteristic map are set. The fuel injection control is performed using the data interpolated with the interpolation data for the transition region .

Accordingly, the first to third regions having different fuel injection modes are provided, the first region and the second region are adjacent to each other, the second region and the third region are adjacent to each other, and the first region and the third region are adjacent to each other. In the case where the areas are not adjacent to each other, the two types of maps, the first injection characteristic map and the second injection characteristic map, are used by switching, and each of the first to third areas and each of the adjacent areas is used. Each fuel injection control in the transient region can be performed with high accuracy in accordance with required control characteristics.

That is, the interpolation data is set to a portion of the second region of the first injection characteristic map, but is set to a portion of the first region and the third region each of the second injection characteristic map, the area Therefore , the data is used only in the transition region in the middle of shifting from one of the adjacent regions to the other . Meanwhile, for the interpolation data from being set in a part of the region reflects the control characteristic required in the region, moreover, it is configured with the source of jetting modes.

Thus, performing the fuel injection control in the transition region, the data interpolation by a migration source area to the set control data and the destination area of the set interpolation data, the data between the same jetting mode And interpolation based on data reflecting control characteristics required in the transfer source area and data reflecting control characteristics required in the transfer destination area. For this reason, the data obtained by the data interpolation accurately reflects the control characteristics required in the transition region, that is, a value suitable for the fuel injection control in the transition region.

Therefore, according to the present invention, the fuel injection control in the transition region of the course of transition from one to the other of Aitonaru region, by meeting the required control characteristics Ru can be accurately performed.

In particular, in the above case, it is also to be considered that should make the injection characteristic map dedicated its injection mode for each injection mode using switching this Doing so, the number of the injection characteristic map However, according to the present invention, the problem is solved by switching between two types of maps, the first injection characteristic map and the second injection characteristic map. it can be avoided by.

In the invention according to claim 2 , the fuel injection control region based on the engine operating state includes a first region group composed of a plurality of regions that are not adjacent to each other, and a second region group composed of the remaining regions that are not adjacent to each other. The region of the first region group and the region of the second region group adjacent to each other is a fuel injection control method for an engine having different fuel injection modes by the fuel injection valves,
A first injection characteristic map and a second injection characteristic map in which data relating to at least one of the fuel injection timing and the injection amount are respectively set;
In the first injection characteristic map, as the above data, control data set in each area of the first area group and a part of the area of the second area group adjacent to each area of the first area group are set. Interpolation data, the interpolation data is set in the same ejection manner as the area of the adjacent first area group,
In the second injection characteristic map, as the above data, the control data set in each area of the second area group and a part of the area of the first area group adjacent to each area of the second area group are set. Interpolation data, and the interpolation data is set in the same ejection manner as the area of the adjacent second area group,
When the engine operating state exists in each region of the first region group and the second region group, fuel injection control is performed using a corresponding injection characteristic map in which control data for the region is set,
In the transitional region in the middle of the transition of the engine operating state from the region of the first region group to the region of the adjacent second region group, control data set in the region of the first region group of the first injection characteristic map; Using the data interpolated with the interpolation data set in a part of the second region group, fuel injection control is performed in the same injection manner as the first region group,
When the engine operating state shifts to the region of the second region group, the map used for fuel injection control is switched from the first injection characteristic map to the second injection characteristic map,
In the transition region in the middle of the transition of the engine operating state from the region of the second region group to the region of the first region group adjacent thereto, control data set in the region of the second region group of the second injection characteristic map; Using the data interpolated with the interpolation data set in a part of the region of the first region group, fuel injection control is performed in the same injection manner as the region of the second region group,
When the engine operating state shifts to the region of the first region group, the map used for fuel injection control is switched from the second injection characteristic map to the first injection characteristic map.

    Accordingly, the fuel injection control region is divided into a first region group composed of a plurality of regions that are not adjacent to each other and a second region group composed of the remaining regions that are not adjacent to each other. In the case where the fuel injection modes of the second region group and the second region group are different from each other, the two types of maps, the first injection characteristic map and the second injection characteristic map, are used by switching to each region and adjacent to each other. Each fuel injection control in each transition region between the regions can be accurately performed in accordance with the required control characteristics.

The invention according to claim 3 is the invention according to claim 1 or claim 2 ,
The injection characteristic map is characterized in that data is recorded using a torque required for the engine as a parameter.

    Therefore, it is advantageous in changing the injection mode without causing a torque shock.

As described above, according to the first aspect of the present invention, the fuel injection control region based on the engine operating state includes the first to third regions having different fuel injection modes, and the first region and the second region. In the case where the region is adjacent, the second region and the third region are adjacent, and the first region and the third region are not adjacent, the control data for the first injection mode set in the first region, Control data of the third injection mode set in the third region, interpolation data of the first injection mode set in a part of the second region used for the transition region transitioning from the first region to the second region, And a first injection characteristic map having data for interpolation of the third injection mode set in a part of the second region used in the transition region transitioning from the third region to the second region, and set in the second region Control data for the second injection mode, transition from the second region to the third region The interpolation data for the second injection mode set in a part of the third area used for the transition area and the part of the first area used for the transition area transitioning from the second area to the first area are set. A second injection characteristic map having interpolation data for the second injection mode is prepared, and when the engine operating state is in each of the first to third regions, the first control data for the region is set. Alternatively, the fuel injection control is performed using the control data in the second injection characteristic map, and the first injection characteristic map and the second time each time the engine operating state shifts between the first to third adjacent regions. The injection characteristic map is alternately switched to perform fuel injection control using the control data set in the transition destination region. In the transient region, the first or second control data in the transition source region is set. Control data of the injection characteristic map Since the fuel injection control is performed using the data interpolated by the interpolation data for the transition region set in a part of the transition destination region of the injection characteristic map, the two types of maps are switched. By use, the fuel injection control in each of the first to third regions and each transition region can be performed with high accuracy in conformity with the required control characteristics.

  According to the second aspect of the invention, the fuel injection control region based on the engine operating state includes the first region group composed of a plurality of regions not adjacent to each other and the second region composed of the remaining regions not adjacent to each other. Control set in each region of the first region group in the case where the fuel injection mode by the fuel injection valve is different between the region of the first region group and the region of the second region group which are divided into groups. Data and interpolation data set in a part of the region of the second region group adjacent to each region of the first region group, and the interpolation data includes the region of the adjacent first region group The first injection characteristic map set in the same injection mode, the control data set in each area of the second area group, and a part of the area of the first area group adjacent to each area of the second area group Interpolation data that has been set. When a second injection characteristic map set in the same injection manner as the area of the adjacent second area group is prepared and the engine operating state exists in each area of the first area group and the second area group, In the transitional region in the middle of the transition of the engine operating state from the first region group region to the adjacent second region group region, the fuel injection control is performed using the corresponding injection characteristic map in which the control data is set. First, using data interpolated by the control data set in the region of the first region group of the first injection characteristic map and the interpolation data set in a part of the region of the second region group, the first When the fuel injection control is performed in the same injection mode as that region of the region group, and the engine operating state shifts to the region of the second region group, the map used for the fuel injection control is changed from the first injection characteristic map to the second injection property map. Characteristic map In the transitional region in the middle of switching and engine operating state from the region of the second region group to the region of the adjacent first region group, the control data set in the region of the second region group of the second injection characteristic map And the data interpolated by the interpolation data set in a part of the region of the first region group, the fuel injection control is performed in the same injection manner as the region of the second region group, and the engine operating state is Since the map used for the fuel injection control is switched from the second injection characteristic map to the first injection characteristic map when shifting to the corresponding area of the one area group, the two types of maps are switched and used. In addition, each fuel injection control in each transition region between adjacent regions can be performed with high accuracy in accordance with required control characteristics.

    Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

    In FIG. 1, 1 is a multi-cylinder diesel engine of a vehicle (only one cylinder is shown in FIG. 1), 2 is its intake passage, and 3 is its exhaust passage. A deep dish combustion chamber 5 is formed on the top surface of the piston 4 of the engine 1. The cylinder head of the engine 1 is provided with a fuel injection valve 7 so that fuel can be directly injected into the in-cylinder combustion chamber 5.

  In the intake passage 2, the air cleaner 9, the air flow sensor 10, the blower 11 a of the turbocharger 11, the intercooler 12, the intake throttle valve 13, the intake temperature sensor 14, and the intake pressure are sequentially arranged from the upstream side to the downstream side. A sensor 15 is provided. In the exhaust passage 3, a turbine 11 b of the turbocharger 11, an oxidation catalyst 16, and a DPF (diesel particulate filter) 17 that collects particulates in the exhaust gas are arranged in order from the upstream side to the downstream side. ing. Exhaust pressure sensors 18 and 19 are disposed upstream and downstream of the DPF 17. The DPF 17 carries an oxidation catalyst at a site upstream thereof.

  Further, the upstream side of the exhaust passage 3 with respect to the turbine 11b and the downstream side of the intake passage 2 with respect to the intake pressure sensor 15 are connected by an exhaust gas recirculation passage 21 for returning a part of the exhaust gas to the intake system. . In the middle of the exhaust gas recirculation passage 21, a negative pressure actuator type exhaust gas recirculation amount control valve (EGR valve) 22 and a cooler 23 for cooling the exhaust gas with engine coolant are disposed.

  Fuel in a fuel tank (not shown) is supplied to the fuel injection valve 7 by a fuel supply pipe 28 via a fuel filter 25, a high-pressure fuel pump 26, and a common rail 27 as pressure accumulating means, and is supplied to the fuel tank by a fuel return pipe 29. Returned. That is, the high pressure fuel pumped from the fuel pump 26 is stored in the common rail 27, and the fuel stored in the common rail 27 is distributed and supplied to the fuel injection valves 7 of the cylinders of the engine 1. The fuel injection valve 7, the fuel tank, the fuel filter 25, the high pressure fuel pump 26, the common rail 27, the fuel supply pipe 28, and the fuel return pipe 29 constitute a fuel supply system. The common rail 27 is provided with a fuel pressure sensor 30 for detecting the fuel pressure in the common rail.

  31 is a water temperature sensor that detects the engine water temperature, 32 is a crank angle sensor that detects the engine speed, 33 is a sensor that detects the exhaust gas temperature flowing into the oxidation catalyst 16, 34 is a sensor that detects the exhaust gas temperature flowing into the DPF 17, Reference numeral 35 denotes a sensor for detecting the temperature of exhaust gas flowing out from the DPF 17.

  Thus, in order to control the operation of the fuel injection valve 7, the engine speed detected by the engine speed sensor 41, the accelerator opening (accelerator pedal depression amount) detected by the accelerator opening sensor 42, and other Parameters (detected values such as the fuel pressure sensor 30 and the water temperature sensor 31) are given to the control means 40. That is, based on the above various parameters, fuel injection control is performed by an ECU (engine control unit using a microcomputer) with reference to injection characteristic data.

    As shown in FIG. 2, the fuel injection control region based on the engine operating state is divided into a plurality of regions having different fuel injection patterns (injection modes).

    That is, in the first region (low torque / low rotation region) V, pilot injection for injecting fuel during the compression stroke is performed prior to main injection for injecting fuel near the compression top dead center, as shown in FIG. The process is divided into three times (P3 stage injection pattern a). In the second region (medium torque / medium rotation region) W surrounding the first region V, pilot injection is performed in two divided prior to the main injection (P2-stage injection pattern b). In the third region (high torque side and high rotation side region) X surrounding the second region W, pilot injection is performed only once (P1 stage injection pattern c) prior to main injection. The lower the torque or the lower the rotational speed, the more the number of pilot injections is increased in order to avoid sudden combustion of the engine and to reduce the combustion noise, thereby reducing the amount of NOx generated. In the third region X, soot is likely to be generated, so that the pilot injection is executed only once in the advanced state in order to reduce soot by premixed combustion.

    Further, in the fourth region Y set to the middle torque / high rotation side in the third region X, pilot injection and post injection (injecting fuel in the expansion stroke after the main injection) are executed (P1). Stage split injection pattern d). This post-injection is performed to raise the temperature of the DPF 17 for combustion of the collected particulates. In the fifth region (high torque / high rotation region) Z, only main injection is performed (single injection pattern e). This is to ensure a sufficient output by injecting the entire target fuel injection amount in a short time by main injection.

    Thus, in the fuel injection control, the first injection characteristic map and the first electronically stored data relating to the fuel injection timing and the injection amount are stored in advance using the required torque of the engine and the engine speed as parameters. This is performed by using two types of injection control maps called two-injection characteristic maps. In order to perform the fuel injection control using these two types of maps, the regions V to Z are adjacent to the first region group (group 0) composed of a plurality of regions W, Y, and Z that are not adjacent to each other and the remaining regions. It is grouped into a second region group (group No. 1) consisting of a plurality of regions V and X that are not present. In each of the maps, control data and interpolation data are set as the data.

    In the first injection characteristic map, as the above data, control data based on the injection pattern of the first area group is set in each of the areas W, Y, and Z of the first area group, and the areas W, Y, and Z of the first area group are set. Interpolation data is set in a part of each of the regions V and X of the second region group adjacent to each other. In the second injection characteristic map, control data based on the injection pattern of the area is set in each of the areas V and X of the second area group as the data, and the second adjacent to the areas V and X of the second area group. Interpolation data is set in a part of each of the areas W, Y, and Z in one area group.

    The first injection characteristic map and the second injection characteristic map will be described in more detail with reference to FIG. The upper left of the figure shows the first injection characteristic map, and the upper right of the figure shows the second injection characteristic map. For the sake of simplicity, both maps are shown by extracting portions corresponding to the regions V, W, and X in FIG.

    In the both injection characteristic maps of FIG. 4, the first region V is a portion where the required torque is A, B and the engine speed is I, II, III (in the thick line frame on the upper side of the second injection characteristic map), The second region W includes parts where the required torque is C and D and the engine speed is I, II, III and IV, and parts where the required torques A and B are the engine speed IV (thick line frame in the first injection characteristic map). The third region X is a region where the required torque is E, F and the engine speed is I, II, III, IV (inside the thick line frame below the second injection characteristic map).

    Each position (each cell portion of the map shown in a table form in FIG. 4) in the second region W of the first injection characteristic map determined by two parameters “request torque” and “engine speed” Data for control in the P2 stage injection pattern b used for fuel injection control at is set. Further, at each position in the first region V of the second injection characteristic map, control data in the P3 stage injection pattern a used for fuel injection control at the position is set, and the third region X of the map In each position, control data in the P1 stage injection pattern c used for fuel injection control at the position is set.

    Thus, in the first injection characteristic map, a part of the first region V that is the region adjacent to the second region W and a part of the third region X that is also the region adjacent to the second region W are Interpolation data is set in the same P2 stage injection pattern b as in the second region W. Interpolation data set in a part of the first region V has a transitional region in the middle of the engine operating state transitioning from the second region W to the first region V (for example, at the engine speed II, the required torque is B In a region smaller than C) is used for interpolation of data for fuel injection control.

    That is, in the transition region, the data is interpolated by the control data set in the second region W and the interpolation data set in a part of the first region V, and the fuel is generated in the P2 stage injection pattern b. The injection control is performed. In this case, the interpolation data is not used for fuel injection control in the first region V, but reflects the control characteristics required at the position where the interpolation data in the first region V is set. Yes. That is, the interpolation data is data suitable for control when the interpolation data setting position in the first region V adopts the P2 stage injection pattern b instead of the P3 stage injection pattern a. . As a result, the data obtained by the interpolation accurately reflects the control characteristics required in the transient region.

    Similarly, the interpolation data set in a part of the third region X is the fuel injection in the P2 stage injection pattern b in the transition region in the middle of the engine operating state shifting from the second region W to the third region X. Used to interpolate data with the control data in the second area W to perform control, and reflects the control characteristics required at the interpolation data setting position in the third area V It is said.

    The interpolation data for the first region V is set along the boundary between the first region V and the second region W, and the interpolation data for the third region X is between the third region X and the second region W. It is set along the boundary. That is, in the first injection characteristic map, the data of the P2 stage injection pattern b is not only set in the second region W, but also across the boundary between the first region V and the second region W. Is also set to a part of the boundary side in the third region X across the boundary between the second region W and the third region X. Therefore, the data interpolation is performed using the control data and the interpolation data adjacent to each other with the boundary of the region of the first injection characteristic map (for example, the boundary between the first region V and the second region W) interposed therebetween. .

    On the other hand, in the second injection characteristic map, interpolation data is set in a part of the second region W, which is a region adjacent to the first region V, with the same P3 stage injection pattern a as that of the first region V. This interpolation data is the same as the control data for the first region V in order to perform fuel injection control with the P3 stage injection pattern a in the transition region where the engine operating state is shifting from the first region V to the second region W. Between the first area V and the second area W, and is set along the boundary between the first area V and the second area W. That is, the data of the P3 stage injection pattern a is not only set in the first region V, but also part of the boundary side in the second region W across the boundary between the first region V and the second region W. It is also set. Thus, the interpolation data reflects the control characteristics required at the interpolation data setting position in the second region W.

    Further, in the second injection characteristic map, interpolation data is set in a part of the second region W that is an adjacent region of the third region X with the same P1 stage injection pattern c as that of the third region X. This interpolation data is the same as the control data for the third region X in order to perform the fuel injection control with the P1 stage injection pattern c in the transition region in the middle of the transition of the engine operating state from the third region X to the second region W. Between the second area W and the third area X, and is set along the boundary between the second area W and the third area X. That is, the data of the P1 stage injection pattern c is not only set in the third region X but also part of the boundary side in the second region W across the boundary between the second region W and the third region X. It is also set. Thus, the interpolation data reflects the control characteristics required at the interpolation data setting position in the second region W.

    The parameters (required torque and engine speed) that define each position of the both injection characteristic maps are numerical values within a range of “1000 rpm to less than 1100 rpm” even if the numerical value is, for example, “1000 rpm”. Also good. Further, the engine speed I is “700 rpm to less than 800 rpm”, and the engine speed II is “800 rpm to less than 900 rpm”. Position may be set so that II) does not become discontinuous. When the parameters of each position are set discontinuously, interpolation data is used to control the discontinuous portion.

    However, the parameters of the positions in adjacent regions are discontinuous (for example, torque B and torque C are discontinuous, and engine speed III and engine speed IV are discontinuous).

    In the first and second injection characteristic maps of FIG. 4, the portions of the fourth and fifth regions Y and Z of FIG. 2 are omitted, but the fourth and fifth regions Y are shown in both maps. , Z portions are also provided.

    In the first injection characteristic map, control data for the P1 stage split injection pattern d is set in the fourth area Y, and control data for the single injection pattern e is set in the fifth area Z. Furthermore, interpolation data for the P1-stage split injection pattern d is set in a portion along the boundary between the third region X and the fourth region Y, which is a part of the third region X, and similarly, the third region X In a part along the boundary between the third region X and the fifth region Z, which is a part of the data, interpolation data for the single injection pattern e is set.

    The data for interpolation of the P1 stage split injection pattern d set in the third area X is the fuel in the P1 stage split injection pattern d in the transitional area in the middle of the transition of the engine operating state from the fourth area Y to the third area X. In order to perform injection control, it is used to interpolate data with the control data in the fourth region Y. Interpolation data for the single injection pattern e set in the third region X The data for interpolation is the fuel injection with the single injection pattern e in the transition region in the middle of the engine operating state shifting from the fifth region Y to the third region X. It is used to interpolate data with the control data in the fifth region Z to perform control.

    On the other hand, in the second injection characteristic map, interpolation data of the P1 stage injection pattern c is set in a portion along the boundary between the third region X and the fourth region Y, which is a part of the fourth region Y. In a portion along the boundary between the third region X and the fifth region Z, which is a part of the fifth region Z, interpolation data for the P1 stage injection pattern c is set. The interpolation data set in the fourth region Y includes the third data in order to perform fuel injection control with the P1 stage injection pattern c in the transitional region in the middle of the engine operating state shifting from the third region X to the fourth region Y. This is used to interpolate data with the control data in region X. The data for interpolation set in the fifth region Z is the third in order to perform the fuel injection control with the P1 stage injection pattern c in the transition region in the middle of the engine operating state shifting from the third region X to the fifth region Z. This is used to interpolate data with the control data in region X.

    In relation to the fourth region Y and the fifth region Z, the interpolation data set in each of the first injection characteristic map and the second injection characteristic map is the control characteristic required at the interpolation data setting position. Is reflected.

    Next, fuel injection control using the first injection characteristic map and the second injection characteristic map will be described according to the control flow shown in FIG.

    In step S1 after the start, fuel injection control parameters such as the engine speed Ne and the accelerator opening θ are read, and in step S2, the torque required for the engine is calculated based on the engine speed Ne and the accelerator opening θ. . In a succeeding step S3, it is determined whether or not the engine operating state has shifted to a region where the injection characteristic map is switched. For example, when the engine operating state is in the second region W, it is determined whether or not the engine operating state has shifted from the second region W to the adjacent third region X through a transition region on the way.

    When it is determined to shift to the region for switching the injection characteristic map, the process proceeds to step S4, and it is determined whether or not the first injection characteristic map of group 0 is being used. As will be described later, since “flag 0” is set when the first injection characteristic map of group 0 is used, the determination is made by a flag (flag 0?). When it is determined that the first injection characteristic map of group 0 is being used, the process proceeds to step S5, "Flag 1" is set, and in step S6, the map to be used is changed to the second injection characteristic of group 1. The map is switched to and the fuel injection control is executed by the second injection characteristic map (step S7).

    If it is not determined in step S3 that the injection characteristic map is to be switched, the process proceeds to step S8, where it is determined whether or not “flag 0” is set (the first injection characteristic map of group 0 is being used). judge. When the first injection characteristic map of group No. 0 is being used, the process proceeds to step S9, and fuel injection control by the first injection characteristic map is continued. When the first injection characteristic map of group 0 is not being used, that is, when the second injection characteristic map of group 1 is being used, the process proceeds to step S7, and fuel injection control based on the second injection characteristic map is performed. Will continue.

    That is, for example, when the engine operating state shifts from the second region W to the adjacent third region X through a transition region on the way, the map to be used is switched from the first injection characteristic map to the second injection characteristic map. (Step S6) When the engine operating state is still in the transition region during the transition, the first injection characteristic map is continuously used. In the transition region, the control data and the third region in the second region W are used. The fuel injection control is executed by interpolating the data with the interpolation data set to X.

    Regarding the switching of the injection characteristic map, when it is determined in step S4 that the first injection characteristic map of group 0 is not being used, that is, when the second injection characteristic map of group 1 is being used. In step S10, "flag 0" is set, and in the subsequent step S11, the map to be used is switched to the first injection characteristic map of group 0, and fuel injection control is executed using the first injection characteristic map (step S9). ).

    In the lower column of FIG. 4, a case of transition from “NEII, torque D” in the second region W taking the P2 stage injection pattern b to “NEII, torque E” in the third region X taking the P1 stage injection pattern c. Is illustrated. In other words, this is an example of data interpolation in the transition region “between NE II and torque DE” during the transition. Note that “between D and E” is a section in which the required torque is larger than D and smaller than E.

    In this case, in “NEII, torque D” in the second region W, fuel injection control is performed using the control data for the P2 stage injection pattern b set in “NEII, torque D” in the first injection characteristic map. . When the engine operating state enters the transitional region “between NEII and torque DE”, the control data for the P2 stage injection pattern b set in “NEII, torque D” in the second region W of the first injection characteristic map; The data is interpolated by the interpolation data of the P2 stage injection pattern b set in “NEII, torque E” in the third region X of the map, and the fuel injection is performed by the interpolated data by the P2 stage injection pattern b. Control is performed.

    Since the interpolation data set in the “NEII, torque E” reflects the control characteristics required in the “NEII, torque E” position, the transient region “NEII, torque D− The data for “between E” control accurately reflects the control characteristics required in this transition region.

    Then, when the engine operating state shifts to “NEII, torque E” in the third region X through the transition region, the map used for control is switched from the first injection characteristic map to the second injection characteristic map, The fuel injection control is performed with the P1 stage injection pattern c based on the control data set in “NEII, torque E” in the third region X of the second injection characteristic map.

1 is an overall configuration diagram of an engine fuel injection control apparatus according to the present invention. It is a graph which shows the fuel-injection control area | region of the engine which concerns on this invention divided by the fuel-injection pattern. It is explanatory drawing of various fuel injection patterns. It is a figure which shows the injection characteristic map which concerns on this invention, and the example of injection control of a transient area. It is a flowchart of the control method which concerns on this invention. It is a figure which shows the conventional injection characteristic map and the example of injection control of a transient area.

DESCRIPTION OF SYMBOLS 1 Engine 7 Fuel injection valve 40 Control means V 1st area | region W 2nd area | region X 3rd area | region Y 4th area | region Z 5th area | region

Claims (3)

As a fuel injection control region based on the engine operating state, a first region in which fuel injection by the fuel injection valve is performed in the first injection mode, and a second injection mode in which the fuel injection is performed in a second injection mode different from the first injection mode. and the region, and a third region which is performed at a different third jetting mode and the fuel injection is the first injection mode and a second jetting mode, have if next to the above-described first region and the second region, A fuel injection control method for an engine in which the second region and the third region are adjacent to each other, and the first region and the third region are not adjacent to each other ,
A first injection characteristic map and a second injection characteristic map in which data relating to at least one of the fuel injection timing and the injection amount are respectively set;
The first injection characteristic map is used for interpolation of data in the first injection mode control data set in the first area and a transition area in the middle of transition from the first area to the second area. the interpolation data of the first jetting mode which is set in a part of the second region, the third and the control data of the third injection mode set in the region, the second region from the third region The third injection mode interpolation data set in a part of the second area, used for data interpolation in the transition area in the middle of
The second injection characteristic map is used for data interpolation in the transition region in the middle of transition from the second region to the third region, and the control data for the second injection mode set in the second region. The interpolation data of the second injection mode set in a part of the third region and the first region used for data interpolation in the transition region in the middle of transition from the second region to the first region. Data for interpolation of the second injection mode set in part,
When the engine operating state exists in each of the first to third regions, fuel injection control is performed using the control data in the first or second injection characteristic map in which the control data for the region is set. Done
Whenever the engine operating state shifts between the first to third adjacent regions, the first injection characteristic map and the second injection characteristic map are alternately switched, and the control data set in the transfer destination region is obtained. To control fuel injection,
In the transition region in the middle of the transition, the control data of the first or second injection characteristic map in which the control data of the transition source region is set and a part of the transition destination region of the injection characteristic map are set. A fuel injection control method for an engine, characterized in that fuel injection control is performed using data interpolated with interpolation data for the transition region . The fuel injection control region based on the engine operating state is divided into a first region group composed of a plurality of regions not adjacent to each other and a second region group composed of the remaining regions not adjacent to each other. The region of the first region group and the region of the second region group are engine fuel injection control methods in which fuel injection modes by the fuel injection valves are different from each other,
A first injection characteristic map and a second injection characteristic map in which data relating to at least one of the fuel injection timing and the injection amount are respectively set;
In the first injection characteristic map, as the above data, control data set in each area of the first area group and a part of the area of the second area group adjacent to each area of the first area group are set. Interpolation data, the interpolation data is set in the same ejection manner as the area of the adjacent first area group,
In the second injection characteristic map, as the above data, the control data set in each area of the second area group and a part of the area of the first area group adjacent to each area of the second area group are set. Interpolation data, and the interpolation data is set in the same ejection manner as the area of the adjacent second area group,
When the engine operating state exists in each region of the first region group and the second region group, fuel injection control is performed using a corresponding injection characteristic map in which control data for the region is set,
In the transitional region in the middle of the transition of the engine operating state from the region of the first region group to the region of the adjacent second region group, control data set in the region of the first region group of the first injection characteristic map; Using the data interpolated with the interpolation data set in a part of the second region group, fuel injection control is performed in the same injection manner as the first region group,
When the engine operating state shifts to the region of the second region group, the map used for fuel injection control is switched from the first injection characteristic map to the second injection characteristic map,
In the transition region in the middle of the transition of the engine operating state from the region of the second region group to the region of the first region group adjacent thereto, control data set in the region of the second region group of the second injection characteristic map; Using the data interpolated with the interpolation data set in a part of the region of the first region group, fuel injection control is performed in the same injection manner as the region of the second region group,
A fuel injection control method for an engine, wherein a map used for fuel injection control is switched from the second injection characteristic map to the first injection characteristic map when the engine operating state shifts to the region of the first region group. . In claim 1 or claim 2 ,
The fuel injection control method for an engine is characterized in that the injection characteristic map records data using a torque required for the engine as a parameter.

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