JP4122744B2 - Engine fuel injection amount control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a two-cycle, four-cycle engine for a motorcycle or the like that supplies fuel by fuel injection (injection), and includes a DJ map (determining the basic injection amount based on the relationship of suction negative pressure * engine speed) The present invention relates to a fuel injection amount control device that performs injection control by switching each map when there are two types of basic injection amount maps of αN maps (: the basic injection amount is determined from the relationship of throttle opening * engine speed).
[0002]
[Prior art]
2. Description of the Related Art There are types of motorcycle engine units that use a fuel injection device in addition to a carburetor as a fuel supply device. In this type of motorcycle fuel injection device, the basic injection amount map used for injection control is a DJ map (determined by the relationship between the suction negative pressure and the engine speed), as shown in FIG. There are two types of αN maps as shown in FIG. 6 (the fuel injection amount is determined from the relationship between the throttle opening and the engine speed), and the basic injection amount is determined by selecting one of the maps. The amount of fuel injected from the injector into the intake pipe is determined by correcting the amount as necessary (refer to, for example, Japanese Patent Laid-Open No. 2-136531 regarding the fuel injection amount device).
[0003]
As shown in FIG. 7, the correlation between the throttle opening and the suction negative pressure changes abruptly when the throttle opening is small (A: range where the amount of change in the suction negative pressure is large relative to the throttle opening, B: suction negative Therefore, the point where the throttle opening and the negative suction pressure are balanced is set as the optimum switching point (indicated by symbol C in FIG. 7). When the opening is small, the amount of change in the suction negative pressure is larger than the amount of change in the throttle opening, so the DJ map is used (area A). On the other hand, when the throttle opening is larger than the switching point, the reverse is true. Therefore, the fuel injection amount is controlled using the αN map (area B).
That is, in the conventional injection amount control, the basic injection amount is determined by the DJ map if it is below a certain throttle opening, and the basic injection amount is determined by the αN map if it is above a certain throttle opening. , Switched the map to control.
[0004]
[Problems to be solved by the invention]
However, according to the inventor's knowledge, the relationship between the throttle opening and the suction negative pressure changes according to the engine speed, so that as shown in FIG. 8, for example, as the engine speed increases, the throttle opening As the suction negative pressure increases, the range in which the change rate of the suction negative pressure is large is widened. For this reason, there is an engine speed range in which switching between the DJ map and the αN map is not optimal, and the constant throttle opening In the control for switching the map, there is a problem in that the injection amount cannot be finely controlled and the running feeling is deteriorated.
[0005]
The present invention has been made paying attention to the above-mentioned problems of the prior art, and when the engine speed changes, even if the correlation with the throttle opening or the intake negative pressure is different, the map switching condition can be set in the engine. An object of the present invention is to provide a fuel injection amount control device for an engine that can determine the fuel injection amount optimally and finely according to the rotational speed.
[0006]
[Means for Solving the Problems]
As a result of various studies by the inventor, as shown in FIG. 8 described above, the relationship between the throttle opening and the suction negative pressure changes according to the engine speed, so the DJ map and the αN map also change. As a result, the switching point also changes, and in the high speed range where the suction negative pressure changes greatly, the area where the control by the DJ map is advantageous increases. Conventionally, the DJ map and the αN map are switched by a certain throttle opening in all engine speed ranges, so fine control cannot be performed, and optimal switching control is always performed in the low and high speed ranges. It wasn't. Therefore, the inventor has determined that it is appropriate to set the switching point based on this point, focusing on the point where the amount of change in the suction negative pressure and the amount of change in the throttle opening balance at each engine speed. Thus, the present invention has been invented.
[0007]
The present invention stores the second basic injection amount map and the first basic injection amount map and the engine intake negative pressure and parameters of the engine rotational speed of the throttle opening and the engine speed as a parameter in the memory, the engine rotation For each number, the suction negative pressure value when the absolute value of the change amount of the throttle opening and the change amount of the suction negative pressure becomes substantially equal before and after is set as the first switching point, and the suction negative pressure is set to the first value . The fuel injection amount is determined based on the second basic injection amount map when larger than the switching point, while the fuel injection amount is determined based on the first basic injection amount map when the suction negative pressure is smaller than the first switching point. An engine fuel injection amount control device for determining ,
In this fuel injection amount control apparatus, apart from the first switching point corresponding to the suction negative pressure, the absolute value of the change amount of the throttle opening and the change amount of the suction negative pressure is changed before and after each engine speed. Means for setting the throttle opening value when substantially equal as the second switching point;
The throttle opening reaches the second switching point earlier than the suction negative pressure reaches the first switching point due to the response delay of the suction negative pressure when the throttle opening is changed suddenly. In this case, the fuel injection amount is determined based on the first basic injection amount map when the throttle opening is larger than the second switching point even before the intake negative pressure reaches the first switching point. And a means for switching the first and second basic injection amount maps so as to determine the fuel injection amount based on the second basic injection amount map when the throttle opening is smaller than the second switching point. This is a fuel injection amount control device for an engine.
According to the present invention, it is possible to set the basic injection amount map switching condition for each engine speed in response to the fact that the correlation between the throttle opening and the suction negative pressure differs when the engine speed changes. The optimum fuel injection amount can be determined regardless of the operating state of the engine.
When the engine speed is high, the amount of change in the intake negative pressure is large even if the throttle opening is close to the intermediate range. Therefore, the second basic injection amount map (for example, the engine intake negative pressure and the engine speed is used as parameters) DJ map) can be used for fine control. On the other hand, when the engine speed is low, the amount of change in the suction negative pressure is relatively small even if the throttle opening is in the low opening range. The fuel injection amount can be finely controlled by switching to a first basic injection amount map (for example, an αN map) using the opening degree and the engine speed as parameters.
[0008]
In the present invention, as the switching point, the suction negative pressure value when the absolute value of the change amount of the throttle opening and the change amount of the suction negative pressure is substantially equal before and after the first rotation speed is set as the first switching point . Set as a switching point, and for each engine speed, the throttle opening value when the absolute value of the amount of change in throttle opening and the amount of change in intake negative pressure is approximately equal before and after is used as the second switching point. , the first switching point is intended to set apart. The map switching condition includes a condition that the throttle opening reaches the second switching point earlier than the suction negative pressure reaches the first switching point .
That is, if the throttle opening speed is high, the change in the intake flow rate cannot follow the change in the throttle opening, and a response delay occurs in the intake negative pressure.
Therefore, in addition to the suction negative pressure, a predetermined throttle opening is added to the condition of the switching point, and by switching the map on the condition that the predetermined throttle opening of the two has reached first, the tracking performance is improved. The fuel injection amount can be controlled.
The switching point is the first switching point when the absolute value of the change amount of the throttle opening and the absolute value of the change amount of the suction negative pressure is approximately the same, and the throttle opening value is the second value. Is set as the switching point. Of the amount of change in the throttle opening and the intake negative pressure, which although is unavailable most effectively be two maps higher, when they are equal is the optimal switching point.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a side view of a motorcycle on which an engine according to an embodiment of the present invention is mounted, FIG. 2 is an explanatory diagram of a fuel injection amount control device for the engine, and FIG. 3 is an explanatory diagram of map switching points according to the engine speed. FIG. 4 is an explanatory diagram of switching points depending on the suction negative pressure and the throttle opening.
[0010]
As shown in FIG. 1, the motorcycle is supported by a front wheel 10 and a rear wheel 12 with a frame 14 and an engine 16 sandwiched between them. The frame 14 has a front pipe 14a at a front portion and a front fork 14b in a substantially horizontal direction. The swing arm 14c is supported so as to be rotatable, and the swing arm 14c is supported at the rear so as to be swingable in the vertical direction.
[0011]
Further, a front upper portion and a rear portion of the engine 16 are fixed and suspended on the frame 14, and the engine 16 is installed in a lower engine case 18 and is provided with a cylinder 20 that is inclined in the front-rear direction and has a V-shape in a side view. It is an engine. The engine 16 is provided with intake system throttle bodies 22, 22 at the cylinder heads of the cylinders 20, 20. The throttle bodies 22, 22 are provided with a throttle sensor 24 for detecting a throttle opening, and an air cleaner 25. An intake pressure sensor 26 for detecting the intake negative pressure is disposed on the intake system path from.
[0012]
An engine speed sensor 28 including a signal generator that detects the engine speed is disposed around the crankshaft of the engine 16, and an engine control unit 30 is disposed below the seat at the rear of the vehicle body. . In addition, as a fuel injection system, a front and rear cylinder intake system injector 32, a water temperature sensor 34, an intake air temperature sensor 36, an atmospheric pressure sensor 38, a fuel cut sensor 40, an ignition coil 42, a gear position sensor 44, A fuel pump relay 46 and an ignition switch 48 are provided.
[0013]
As shown in FIG. 2, the engine fuel injection amount control apparatus includes the engine speed output from the engine speed sensor 28, the throttle opening degree from the throttle sensor 24 output, and the intake negative pressure from the intake pressure sensor 26 output. Each detection signal of pressure is input to the engine control unit 30, and the engine control unit 30 uses an αN map (first basic injection amount map) with the throttle opening and the engine speed as parameters, engine intake negative pressure, and engine speed. DJ maps (second basic injection amount maps) with numbers as parameters are stored in the memories 50 and 52, respectively, and switching points are determined according to the engine operating state, and these maps are switched to control the fuel injection amount. An engine fuel injection amount control device is provided.
The fuel injection amount control device determines the fuel injection amount based on the DJ map when the suction negative pressure is larger than a predetermined switching point, and on the other hand, when the suction negative pressure is smaller than the predetermined switching point, the αN map. A control switching determination unit 54 for determining a fuel injection amount based on the engine pressure, a control switching determination unit 54 for setting a predetermined switching point corresponding to the suction negative pressure according to the engine speed, and a fuel amount of the injector with the set injection amount. it is obtained by a injection amount control unit 56 for controlling the injection quantity.
[0014]
In the present embodiment, as shown in FIG. 3, an optimum switching point is set in the determination unit 54 based on the optimum suction negative pressure for each engine rotation set at a constant or appropriate interval (set in advance). And / or may be learned during engine operation). Therefore, since the switching point is optimally set according to the engine speed, even if the correlation between the throttle opening and the negative suction pressure changes when the engine speed changes, the map switching condition is The fuel injection amount can be determined optimally and finely according to the rotational speed.
The predetermined switching point is, for each engine speed, the suction negative pressure when the absolute value of the amount of change in the throttle opening and the amount of change in the suction negative pressure are substantially equal before and after the switching point (for example, when balanced). The one corresponding to is the optimal point.
[0015]
Here, as shown in FIG. 4, a switching point corresponding to a predetermined throttle opening is set separately, and the map switching condition is any of a predetermined suction negative pressure and a predetermined throttle opening. It is preferable to include that the condition has been reached (filled).
That is, in the control by the suction negative pressure, the followability is inferior to the throttle opening, and the suction negative pressure may start to change after a slight delay after the throttle opening starts to change. In this case, the switching point must be set taking into account the response delay. The response delay of the suction negative pressure appears remarkably when the throttle opening is rapidly changed (the throttle opening speed is large).
[0016]
Therefore, in addition to the suction negative pressure, a predetermined throttle opening is added to the switching point condition, and two types of switching points are set, and the map is switched on the condition that one of the two reaches first. Is something to do.
In FIG. 4, a point “a” is a switching point when there is a response delay in the period indicated by a double-ended arrow in FIG. 4, and the suction negative pressure is a parameter. The point “b” uses the throttle opening as a parameter. When the delay period of the suction negative pressure becomes longer, the point “b” reaches the point “b” earlier than the point “a” and is preferentially adopted as a switching point. Here, the point “a” corresponds to the first switching point, and the point “b” corresponds to the second switching point.
In this control, the throttle opening to be set is not a conventional set value, and is not delayed with respect to the transient (when there is no response delay of the suction negative pressure, for example, the suction of “a” in FIG. The throttle opening is such that a negative pressure is obtained, so that the DJ map control in the high rotation range is not hindered.
As described above, by setting an optimal switching point according to the engine speed and switching between the DJ map and the αN map, it is possible to finely control the fuel injection amount over the entire area.
[0017]
In the above embodiment, the switching point for each engine speed is set by the suction negative pressure, but this can also be set by the throttle opening and is within the scope of the present invention. However, in this case, it is not necessary to consider the switching delay at the time of transition, but the optimal switching point varies greatly depending on the engine speed, so that a more accurate setting is required.
[0018]
【The invention's effect】
As described above, according to the present invention, when the engine speed changes, the map switching condition is optimized according to the engine speed even if the correlation with the throttle opening or the suction negative pressure is different. The fuel injection amount can be determined in detail.
[Brief description of the drawings]
FIG. 1 is a side view of a motorcycle on which an engine and a fuel injection control device according to an embodiment of the present invention are mounted.
FIG. 2 is an explanatory diagram of a fuel injection amount control device for the engine.
FIG. 3 is an explanatory diagram of map switching points according to engine speed.
FIG. 4 is an explanatory diagram in the case of selecting one that satisfies a condition first among switching points of suction negative pressure and throttle opening.
FIG. 5 is an explanatory diagram of a DJ map (where the fuel injection amount is determined based on the relationship between the suction negative pressure and the engine speed).
FIG. 6 is an explanatory diagram of an αN map (determining the fuel injection amount from the relationship between the throttle opening and the engine speed).
FIG. 7 is an explanatory diagram of a correlation between a throttle opening and a suction negative pressure.
FIG. 8 is an explanatory diagram of a state where the correlation between the throttle opening and the suction negative pressure changes according to the engine speed.
[Explanation of symbols]
24 Throttle sensor 26 Intake pressure sensor 28 Engine speed sensor 30 Engine control unit 50 α map memory 52 DJ map memory 54 Judging unit 56 Injection amount control unit

Claims (1)

A first basic injection amount map having the throttle opening and the engine speed as parameters and a second basic injection amount map having the engine suction negative pressure and the engine speed as parameters are stored in a memory, and for each engine speed, The suction negative pressure value when the absolute value of the change amount of the throttle opening and the change amount of the suction negative pressure is approximately equal before and after is set as the first switching point, and the suction negative pressure is larger than the first switching point. the second one for determining the basic injection quantity of fuel injection amount based on the map, the engine intake negative pressure determines the fuel injection amount based on the first basic injection amount map when less than the first switching point when A fuel injection amount control device,
In this fuel injection amount control apparatus, apart from the first switching point corresponding to the suction negative pressure, the absolute value of the change amount of the throttle opening and the change amount of the suction negative pressure is changed before and after each engine speed. Means for setting the throttle opening value when substantially equal as the second switching point;
The throttle opening reaches the second switching point earlier than the suction negative pressure reaches the first switching point due to the response delay of the suction negative pressure when the throttle opening is changed suddenly. In this case, the fuel injection amount is determined based on the first basic injection amount map when the throttle opening is larger than the second switching point even before the intake negative pressure reaches the first switching point. And a means for switching the first and second basic injection amount maps so as to determine the fuel injection amount based on the second basic injection amount map when the throttle opening is smaller than the second switching point. A fuel injection amount control apparatus for an engine.

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