JP2002155844A - Engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set an ignition timing according to an air-fuel ratio of a present suction stroke by detecting the stroke state from a phase of a crankshaft and a suction pipe pressure. SOLUTION: The stroke state is detected by the rotation angle of the crankshaft and the suction pipe pressure, a suction air volume sucked in the suction stroke is calculated from the suction pipe pressure relative to a basic ignition timing based on a target air-fuel ratio set before the suction stroke, and when the cylinder air-fuel ratio obtained by the suction air volume and the fuel inflow rate largely differs from the target air-fuel ratio, a new ignition timing is set from the suction pipe pressure, the engine rotation speed, and the air-fuel ratio and corrected. In a case of a suction pipe injection system, the fuel inflow rate is calculated by considering the fuel stuck to the suction pipe and the fuel taken away therefrom and flowing into the cylinder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control device for controlling an engine, and is particularly suitable for controlling an engine having a fuel injection device for injecting fuel.

[0002]

2. Description of the Related Art In recent years, as fuel injectors called injectors have become widespread, it has become easier to control the timing of fuel injection and the amount of injected fuel, that is, the air-fuel ratio, to achieve higher output, lower fuel consumption, and cleaner exhaust gas. Can be promoted. Of these, particularly regarding the fuel injection timing, strictly speaking, the state of the intake valve, that is, generally, the phase state of the camshaft is generally detected, and the fuel is generally injected in accordance therewith.
However, a so-called cam sensor for detecting the phase state of the camshaft is expensive, and cannot be adopted particularly in a motorcycle or the like due to a problem such as an increase in the size of a cylinder head. Therefore, for example, Japanese Patent Application Laid-Open No. H10-227
Japanese Patent Publication No. 252 proposes an engine control device that detects a phase state of a crankshaft and an intake pipe pressure, and detects a stroke state of a cylinder based on the phase state and the intake pipe pressure. Therefore, by using this conventional technique, the stroke state can be detected without detecting the phase of the camshaft.
The fuel injection timing and the like can be controlled according to the stroke state.

[0003]

Incidentally, there is an ignition timing as a control amount for controlling the output characteristics of the engine. The control characteristics of the ignition timing vary depending on the air-fuel ratio in the cylinder.
That is, the output characteristics of the engine can be controlled by controlling the ignition timing according to the air-fuel ratio in the cylinder.

[0004] In the form of injecting fuel by the fuel injection device,
There are a so-called direct injection type that directly injects into the cylinder of the engine, and an intake pipe injection type that injects into the intake pipe. Of these, especially in a direct injection type engine, the amount of fuel flowing into the cylinder can be accurately obtained, so if the amount of intake air is detected, the air-fuel ratio in the cylinder is obtained, and the ignition timing is set accordingly. Can be set.

In order to detect the amount of intake air, a hot wire air flow sensor or a Karman eddy current sensor is generally used.
These are used as sensors for measuring the mass flow rate and volume flow rate respectively. However, in order to eliminate the error factors due to the backflowing air, a volume body (surge tank) that suppresses pressure pulsation
Or installation at a position where the backflow air does not enter. However, many motorcycle engines have a so-called independent intake system for each cylinder, or the engines themselves are single-cylinder engines, and these requirements cannot be sufficiently satisfied in many cases. Even if a flow sensor is used, the amount of intake air cannot be accurately detected.

Further, in the above-described flow sensor, the amount of intake air in the current intake stroke cannot be detected quickly and accurately due to the influence of the volume and the mounting position. Strictly speaking, the calculation of the air-fuel ratio in the cylinder is based on the air-fuel ratio in the next intake stroke, and is not optimal as the ignition timing in the current explosion stroke. In addition, especially in an intake pipe injection type engine, since the amount of fuel actually flowing into a cylinder is ambiguous, an accurate air-fuel ratio in a cylinder can be calculated simply by using a fuel injection amount from a fuel injection device. However, there is a problem that it is difficult to optimize the ignition timing and knocking occurs during acceleration.

As a method of solving such a problem, for example, there is a method of attaching a knocking sensor and controlling the ignition timing to a knocking occurrence limit. However, individual problems such as an increase in cost and a limitation in a knocking detection range occur. I do. There is also a method of setting the ignition timing with a large safety factor so that knocking does not occur. However, individual problems such as a decrease in engine output and a deterioration in fuel efficiency occur.

The present invention has been developed to solve the above problems, and has as its object to provide an engine control device capable of appropriately controlling the ignition timing in the current explosion stroke. .

[0009]

An engine control device according to a first aspect of the present invention includes: a phase detection unit that detects a phase of a crankshaft of a four-cycle engine;
An intake pipe pressure detecting means for detecting an intake pipe pressure in an intake pipe of the engine; and a state of a stroke based on a crankshaft phase detected by the phase detecting means and an intake pipe pressure detected by the intake pipe pressure detecting means. A stroke state detecting means for detecting the intake air pressure, an intake air amount calculating means for calculating an intake air amount based on the intake pipe pressure detected by the intake pipe pressure detecting means, and setting a fuel injection amount to be injected from the fuel injection device. A fuel injection amount setting means and an intake air amount calculated by the intake air amount calculation means immediately before ignition based on a stroke state detected by the stroke state detection means and a fuel injection amount setting means. And an ignition timing setting means for calculating an air-fuel ratio in the cylinder from the fuel injection amount and setting an ignition timing according to the air-fuel ratio.

According to a second aspect of the present invention, the engine control apparatus according to the first aspect further comprises an operating state detecting means for detecting an operating state of the engine, and the ignition timing setting means comprises A basic ignition timing calculating means for calculating a basic ignition timing based on an operating state of the engine detected by the state detecting means; and the suction just before ignition based on a stroke state detected by the stroke state detecting means. In-cylinder air-fuel ratio calculating means for calculating an in-cylinder air-fuel ratio from the intake air amount calculated by the air amount calculating means and the fuel injection amount set by the fuel injection amount setting means, and the in-cylinder air-fuel ratio calculating means And an ignition timing correction means for correcting the basic ignition timing set by the basic ignition timing setting means according to the determined cylinder air-fuel ratio.

According to a third aspect of the present invention, in the engine control apparatus according to the second aspect of the present invention, the ignition timing correction means includes an in-cylinder engine based on the fuel injection amount set by the fuel injection amount setting means. A fuel inflow amount calculating means for calculating a fuel inflow amount flowing into the cylinder, wherein the in-cylinder air-fuel ratio calculating means includes a fuel inflow amount in the cylinder calculated by the fuel inflow amount calculating means and the intake air amount calculating means. The air-fuel ratio in the cylinder is calculated from the calculated intake air amount.

According to a fourth aspect of the present invention, in the engine control apparatus according to the second or third aspect, the ignition timing correcting means includes an engine operating state detected by the operating state detecting means. The basic ignition timing is corrected in consideration of the intake air amount calculated by the intake air amount calculation means.

[0013]

Embodiments of the present invention will be described below. FIG. 1 is a schematic configuration showing an example of an engine for a motorcycle and a control device thereof. The engine 1 is a four-cylinder four-cycle engine, and includes a cylinder body 2, a crankshaft 3, a piston 4, a combustion chamber 5, an intake pipe 6, an intake valve 7, an exhaust pipe 8, an exhaust valve 9, a spark plug 10, an ignition coil 11 is provided. A throttle valve 12 that opens and closes in accordance with the accelerator opening is provided in the intake pipe 6, and an injector 13 as a fuel injection device is provided in the intake pipe 6 upstream of the throttle valve 12. . This injector 1
3 is a filter 1 provided in the fuel tank 19.
8, connected to the fuel pump 17 and the pressure control valve 16. The engine 1 is a so-called independent intake system.
The injector 13 is provided in each intake pipe 6 of each cylinder.

The operating state of the engine 1 is controlled by an engine control unit 15. And
As means for detecting the control input of the engine control unit 15, that is, the operating state of the engine 1, a crank angle sensor 20 for detecting the rotation angle of the crankshaft 3, that is, the phase, the temperature of the cylinder body 2 or the cooling water temperature, That is, a cooling water temperature sensor 21 for detecting the temperature of the engine body, an exhaust air-fuel ratio sensor 22 for detecting an air-fuel ratio in the exhaust pipe 8, an intake pipe pressure sensor 24 for detecting an intake pipe pressure in the intake pipe 6, an intake air An intake air temperature sensor 25 for detecting the temperature in the pipe 6, that is, the intake air temperature is provided. Then, the engine control unit 15
Receives the detection signals of these sensors and outputs control signals to the fuel pump 17, pressure control valve 16, injector 13, and ignition coil 11.

The engine control unit 15
Is constituted by a microcomputer (not shown) or the like. FIG. 2 is a block diagram showing an embodiment of the engine control arithmetic processing performed by the microcomputer in the engine control unit 15. In this calculation process, an engine speed calculating unit 26 for calculating the engine speed from the crank angle signal, and crank timing information, that is, a crank timing detecting unit 27 for detecting the stroke state from the crank angle signal and the intake pipe pressure signal. An intake air amount calculation unit 28 that reads crank timing information detected by the crank timing detection unit 27 and calculates an intake air amount from the intake air temperature signal and the intake pipe pressure signal; A fuel injection amount setting unit 29 that sets a target air-fuel ratio based on the engine speed calculated in the above and the intake air amount calculated by the intake air amount calculation unit 28, and calculates and sets the fuel injection amount and the fuel injection timing. , Reading the crank timing information detected by the crank timing detecting section 27, Wherein an injection pulse corresponding to the fuel injection amount and fuel injection timing set by the tough 29 injector 13
An injection pulse output unit 30 that outputs the engine speed and the crank timing information detected by the crank timing detection unit 27 are read, and the engine speed calculated by the engine speed calculation unit 26 and the fuel injection amount setting unit 29 are read. An ignition timing setting unit 31 for setting an ignition timing based on the fuel injection amount set in the step (c), and the crank timing detection unit 2
And an ignition pulse output unit 32 for reading the crank timing information detected at 7 and outputting an ignition pulse corresponding to the ignition timing set by the ignition timing setting unit 31 to the ignition coil 11. .

The engine speed calculating section 26 calculates the rotational speed of the crankshaft, which is the output shaft of the engine, as the engine speed from the time change rate of the crank angle signal. The crank timing detecting section 27 has a configuration similar to that of the stroke discriminating apparatus described in Japanese Patent Laid-Open No. Hei 10-227252.
As shown in (1), the stroke state of each cylinder is detected and output as crank timing information. That is, in a four-cycle engine, since the crankshaft and the camshaft are constantly rotating with a predetermined phase difference, for example, when a crank pulse is read as shown in FIG.
The crank pulse indicated by “4” is either the exhaust stroke or the compression stroke. As is well known, in the exhaust stroke, the exhaust valve is open, and the intake valve is closed, so the intake pipe pressure is high. In the early stage of the compression stroke, the intake pipe pressure is low, because the intake valve is still open, or the intake valve is low. Is closed, the intake pipe pressure is low in the preceding intake stroke. Accordingly, when the intake pipe pressure is low, the crank pulse of "4" shown in the drawing indicates that the second cylinder is in the compression stroke, and when the crank pulse of "3" shown is obtained, the crank pulse of the second cylinder is lower. Become a dead center. If the stroke state of any one of the cylinders can be detected in this manner, each cylinder is rotating with a predetermined phase difference. For example, the crank pulse of "3" shown in FIG. The next illustrated “9” crank pulse is the intake bottom dead center of the first cylinder, the next illustrated “3” crank pulse is the intake bottom dead center of the third cylinder, and the next illustrated “9”. Is the intake bottom dead center of the fourth cylinder. Then, by interpolating during this stroke with the rotation speed of the crankshaft, the current stroke state can be detected more finely.

As shown in FIG. 4, the intake air amount calculating section 28 detects an intake pipe pressure from the intake pipe pressure signal and the crank timing information.
And a mass flow rate map storage unit 282 storing a map for detecting a mass flow rate of intake air from an intake pipe pressure.
And a mass flow rate calculation unit 283 that calculates a mass flow rate according to the intake pipe pressure detected using the mass flow rate map,
An intake air temperature detecting section 284 for detecting an intake air temperature from the intake air temperature signal; and an intake air temperature based on the mass flow rate of the intake air calculated by the mass flow rate calculating section 283 and the intake air temperature detected by the intake air temperature detecting section 284. And a mass flow rate correction unit 285 for correcting the mass flow rate. That is,
Since the mass map is created based on, for example, the mass flow rate when the intake air temperature is 20 ° C., the mass map is corrected by the actual intake air temperature (absolute temperature ratio) to calculate the intake air amount.

In this embodiment, the intake air amount is calculated using the intake pipe pressure value between the bottom dead center in the compression stroke and the intake valve closing timing. That is, when the intake valve is opened, the intake pipe pressure and the in-cylinder pressure are substantially equal. Therefore, if the intake pipe pressure, the cylinder volume, and the intake temperature are known, the cylinder air mass can be obtained. However, since the intake valve is open for a while after the start of the compression stroke, air flows in and out of the cylinder and the intake pipe during this time, and the intake air amount calculated from the intake pipe pressure before bottom dead center is actually May be different from the amount of air sucked into the cylinder. Therefore, even when the intake valve is opened, the intake air amount is calculated using the intake pipe pressure in the compression stroke in which no air flows between the cylinder and the intake pipe. In addition, in order to further strictly consider the effect of the burned gas partial pressure, a correction may be made in accordance with the engine speed obtained by an experiment using an engine speed having a high correlation with the burned gas partial pressure.

In this embodiment, which is an independent intake system,
As shown in FIG. 5, a mass flow rate map for calculating the intake air amount has a relatively linear relationship with the intake pipe pressure. This is because the required air mass is based on Boyle-Charles' law (PV = nRT). On the other hand, when the intake pipes are connected in all cylinders, the assumption that intake pipe pressure / in-cylinder pressure does not hold due to the influence of the pressure of the other cylinders. You must use a map.

The fuel injection amount setting section 29 includes a target air-fuel ratio calculating section 33 for calculating a target air-fuel ratio based on the engine speed 26 calculated by the engine speed calculating section 26 and the intake pipe pressure signal. A fuel injection amount calculator 34 that calculates a fuel injection amount and a fuel injection timing based on the target air-fuel ratio calculated by the target air-fuel ratio calculator 33 and the intake air amount calculated by the intake air amount calculator 28; The fuel injection amount calculator 34 includes a fuel behavior model 35 used for calculating the fuel injection amount and the fuel injection timing. The fuel behavior model 35 includes an ignition timing setting unit 34 described later.
However, the fuel behavior model 35 and the fuel injection amount calculation unit 34 are substantially integrated. That is, without the fuel behavior model 35, in the present embodiment in which the injection in the intake pipe is performed, accurate calculation and setting of the fuel injection amount and the fuel injection timing cannot be performed. The fuel behavior model 35 requires the intake air temperature signal, the engine speed, and the coolant temperature signal.

The fuel injection amount calculator 34 and the fuel behavior model 35 are configured as shown in, for example, a block diagram of FIG. Here, from the injector 13 to the intake pipe 6
Assuming that the fuel injection amount injected into the fuel injection amount is M _F-INJ and the fuel adhesion rate adhering to the wall of the intake pipe 6 is X, the direct injection of the fuel injection amount M _F-INJ directly injected into the cylinder The amount is ((1−X) × M _F-INJ ), and the amount adhering to the intake pipe wall is (X × M _{F- INJ} ). Some of the deposited fuel flows into the cylinder along the intake pipe wall.
Assuming that the remaining amount is a fuel residual amount _MF-BUF , and of this fuel residual amount _MF-BUF , a carry-out rate taken away by the intake air flow is τ, an amount of carry-out and flow into the cylinder is (τ × _MF-BUF ).

Therefore, in the fuel injection amount calculation section 34,
First, a cooling water temperature correction coefficient K _W is calculated from the cooling water temperature T _W using a cooling water temperature correction coefficient table. Meanwhile, the relative amount of intake air M _A-MAN, for example, performs a fuel cut routine for cutting the fuel when the throttle opening is zero, then using the intake air temperature T _A temperature corrected air flow rate calculates M _a, this multiplied by the inverse ratio of the target air-fuel ratio AF _0, further calculates the cooling water temperature correction factor K _W obtained by multiplying by the required fuel inflow amount M _F. In contrast, with obtaining the fuel adhesion rate X by using the fuel deposition rate map from the engine speed N _E and the intake pipe pressure P _A-MAN, also engine speed N _E and the intake pipe pressure P _A-MAN , The carry-out rate τ is calculated using the carry-out rate map.
Then, by multiplying the carry-off ratio τ in the fuel residual quantity M _F-BUF obtained in the previous operation to calculate the fuel take-away amount M _F-TA, the fuel subtracting it from the required fuel inflow amount M _F Calculate the direct inflow _MF-DIR . As described above, the fuel direct inflow amount _MF-DIR is (1-X) times the fuel injection amount _MF-INJ , and is divided by (1-X) here. Calculate _F-INJ . Also, of the remaining fuel amount _MF-BUF remaining in the intake pipe up to the previous time, ((1−τ)
× M _F-BUF ) also remains this time, and the fuel adhesion amount (X × M _F-INJ ) is added to this to obtain the current fuel remaining amount M
_F-BUF .

The ignition timing setting unit 31 calculates a basic ignition timing based on the engine speed calculated by the engine speed calculation unit 26 and the target air-fuel ratio calculated by the target air-fuel ratio calculation unit 33. Basic ignition timing calculator 36
A fuel behavior model 35 shared with the fuel injection quantity setting unit 29; a fuel inflow amount (equal to a required fuel inflow amount) into a cylinder (cylinder in the figure) calculated by the fuel behavior model 35; From the intake air amount calculated by the air amount calculation unit 28, the in-cylinder air-fuel ratio (in-cylinder A /
F), the in-cylinder air-fuel ratio calculator 37 reads the crank timing information detected by the crank timing detector 27, and calculates the in-cylinder air-fuel ratio calculated by the in-cylinder air-fuel ratio calculator 37 and the basic ignition. An ignition timing correction unit 8 that corrects the ignition timing based on the basic ignition timing calculated by the timing calculation unit 36 is provided.

The basic ignition timing calculation section 36 determines the ignition timing at which the generated torque is the largest based on the current engine speed and the target air-fuel ratio at that time by searching a map or the like, and calculates the basic ignition timing. Further, the in-cylinder air-fuel ratio calculation unit 37 divides the intake air amount calculated by the intake air amount calculation unit 28 by the inflow amount of the cylinder internal combustion amount calculated by the fuel behavior model 35 to obtain the in-cylinder air-fuel ratio. calculate.
Further, the ignition timing correction unit 38 determines, based on the crank timing information, when the in-cylinder air-fuel ratio at the initial stage of the compression stroke that is the same as the calculation of the intake air amount is significantly different from the target air-fuel ratio, The ignition timing is corrected by using the engine speed and the intake pipe pressure to set a new ignition timing in accordance with a control map shown in FIG.

The fuel behavior model 35, the in-cylinder air-fuel ratio calculator 37, and the ignition timing corrector 38 are configured by the arithmetic processing shown in FIGS. This calculation process is performed at the same initial stage of the compression stroke as the calculation of the intake air amount. First, in step S1 of FIG. 7, the detection of the intake air amount is performed again according to the calculation process of FIG. Next, the process proceeds to step S2, where a model calculation of the fuel inflow amount is performed according to a calculation process of FIG. 9 described later.

Next, the process proceeds to step S3, where the intake air amount detected in step S1 is divided by the fuel inflow amount calculated in step S2 to calculate a cylinder air-fuel ratio (in-cylinder A / F in the figure). I do. Next, the process proceeds to step S4, and according to the individual arithmetic processing performed in the step,
For example, when the in-cylinder air-fuel ratio is significantly different from the target air-fuel ratio (a large change in the figure) such that the difference between the in-cylinder air-fuel ratio calculated in step S3 and the target air-fuel ratio is equal to or greater than a predetermined value. Then, the process proceeds to step S5, and if not, the arithmetic processing ends.

In step S5, step S3
Using the in-cylinder air-fuel ratio, the engine speed, and the intake pipe pressure calculated in the above, a new ignition timing (corrected ignition timing in the figure) is calculated in accordance with a control map of FIG. I do. In step S6,
After the ignition timing is corrected by changing the set value of the ignition timing, the arithmetic processing ends.

In the arithmetic processing shown in FIG.
At 11, the engine speed calculated by the engine speed calculator 26 is read. Next, the process proceeds to step S12, where the intake pipe pressure is read. Next, the process proceeds to step S13, where the intake air amount is read from the table in the same manner as in the intake pressure calculation unit 28.

Next, the flow shifts to step S14, where the intake air amount is corrected by the intake air temperature, and then shifts to step S2 of the calculation processing of FIG. In the calculation process of FIG. 9, first, in step S21, the fuel injection amount calculation unit 34
The fuel direct inflow amount is calculated in the same manner as in the description of the fuel behavior model 35 in FIG. Next, in step S22, as described in the fuel behavior model 35 in the fuel injection amount calculation unit 34, of the fuel adhering to the intake pipe, the wall flow flowing into the cylinder along the intake pipe wall. Calculate the minutes.

Next, the process proceeds to step S23, where the fuel adhering to the intake pipe evaporates along with the flow of intake air and the cylinder, similarly to the description of the fuel behavior model 35 in the fuel injection amount calculator 34. Is calculated. Next, the process proceeds to step S24 to calculate the total fuel inflow amount (total inflow amount in the figure) from the total of all the fuels calculated in steps S21 to S23, and then to step S3 of the calculation process in FIG. Move to

The control map shown in FIG. 10 is a three-dimensional map in which, for example, the intake pipe pressure is plotted on the X axis, the engine speed is plotted on the Y axis, and the ignition timing is plotted on the Z axis.
F) is used as a parameter. The air-fuel ratio that is not displayed is used by interpolation. The operation of this arithmetic processing will be described with reference to the timing chart of FIG. In this timing chart, a throttle constant until time t _03, the throttle in a relatively short time between the time t ₁₂ from the time t ₀₃ is opened linearly, then was again throttle constant. In this embodiment, the intake valve is released between the between the time t ₁₄ until time t ₀₇ slightly later than the compression bottom dead center, as well from the time t ₁₂ from a little before time t ₀₄ from the exhaust top dead center It is set as follows. The fuel injection was set to be completed by the start of each intake valve release. As a result, in accordance with the intake valve release from time t _04, since this case is still the throttle opening is small, and injecting the fuel from the time t _02, calculate and said base of the fuel injection amount and fuel injection timing the calculation of the ignition timing, went to a little earlier time t ₀₁ from it. Basic ignition timing set at this time starts the ignition output at time t _05, set to ignite at time t _10.

However, as described above, the time t
Because the throttle in slow time t ₀₃ than ₀₁ began to be opened, more air than the intake air amount calculated by the time t ₀₁ starts to be inhaled. At the time t when the compression stroke is started and the intake valve is closed in order to match this substance.
₀₇ in the previous time t ₀₆ was re-detection and ignition timing correction of the intake air quantity. As a result, in accordance with the cylinder air-fuel ratio becomes smaller than the target air-fuel ratio, the ignition timing is set to a time later t ₁₁ from the time t _10. As a result, the optimum ignition timing can be set based on the air-fuel ratio in the cylinder, the generated torque can be further increased, and the demand for acceleration can be met.

[0033] Similarly, in accordance with the intake valve release from the time t _12, since this case is a little throttle opening is large, and to inject fuel from the time t _09, the fuel injection amount and fuel injection timing the calculation as well as the calculation of the basic ignition timing, went to a little earlier time t ₀₈ from it. However, since even after the throttle is kept open, the time t ₀₈ than the calculated intake air amount in a number for air is inhaled, the compression stroke is started and the intake valve is closed will the time t ₁₄ of the previous It was rediscovered and the ignition timing correction of the intake air amount at time t _13.

As described above, according to the engine control device of the present embodiment, the state of the stroke of the cylinder is detected based on the detected crankshaft angle (phase) and the intake pipe pressure, and the intake pipe pressure immediately before ignition is performed. By calculating the air-fuel ratio in the cylinder from the intake air amount and the fuel injection amount obtained from the above, and setting the ignition timing according to the air-fuel ratio, the air-fuel ratio in the current intake stroke can be obtained. Only the ignition timing can be set accurately.

The basic ignition timing is calculated based on the operating state of the engine such as the engine speed, and the air-fuel ratio in the cylinder is calculated from the intake air amount and the fuel injection amount immediately before the ignition. By correcting the basic ignition timing according to the determined in-cylinder air-fuel ratio, the basic ignition timing is not corrected if, for example, the air-fuel ratio at the time when the basic ignition timing is calculated does not greatly differ from the air-fuel ratio immediately before ignition. In this way, control hunting can be prevented, and the load can be reduced.

Further, the amount of fuel flowing into the cylinder is calculated from the amount of fuel injection, and the air-fuel ratio in the cylinder is calculated from the calculated amount of fuel flowing into the cylinder and the amount of intake air, thereby obtaining the injection in the intake pipe. Even with a model engine, the air-fuel ratio during the current intake stroke can be accurately obtained, and the ignition timing can be set accurately by that amount. Further, since the ignition timing is corrected in consideration of the operation state of the engine such as the engine speed and the intake air amount, the ignition timing can be made more accurate.

In the above embodiment, the in-pipe injection type engine has been described in detail. However, the engine control device of the present invention can be similarly applied to a direct injection type engine. However, in a direct injection engine, since fuel does not adhere to the intake pipe, it is not necessary to consider this, and the calculation of the air-fuel ratio may be performed by substituting the total amount of injected fuel. In the above-described embodiment, a so-called multi-cylinder engine having four cylinders has been described in detail. However, the engine control device of the present invention can be similarly applied to a single-cylinder engine.

Further, the engine control unit includes:
Various arithmetic circuits can be used in place of the microcomputer.

[0039]

As described above, according to the engine control apparatus of the first aspect of the present invention, the phase of the crankshaft of the four-cycle engine is detected, and the pressure of the intake pipe in the intake pipe is detected. A stroke state is detected based on the detected phase of the crankshaft and the intake pipe pressure, an intake air amount is calculated based on the intake pipe pressure, and ignition is performed based on the detected stroke state. Since the air-fuel ratio in the cylinder is calculated from the immediately preceding intake air amount and the fuel injection amount, and the ignition timing is set according to the air-fuel ratio, the air-fuel ratio in the current intake stroke can be obtained. Only the ignition timing can be set accurately.

Further, according to the engine control device of the present invention, the basic ignition timing is calculated based on the operating state of the engine, and based on the detected stroke state, the basic ignition timing is calculated immediately before ignition. Since the air-fuel ratio in the cylinder is calculated from the intake air amount and the fuel injection amount, and the basic ignition timing is corrected according to the calculated air-fuel ratio in the cylinder, for example, the air-fuel ratio at the time when the basic ignition timing is calculated If the air-fuel ratio does not greatly differ from the air-fuel ratio immediately before ignition, the basic ignition timing is not corrected, so that control hunting can be prevented or the load can be reduced.

According to the engine control apparatus of the third aspect of the present invention, the amount of fuel flowing into the cylinder is calculated from the set fuel injection amount, and the calculated amount of fuel flowing into the cylinder is calculated. And the air-fuel ratio in the cylinder is calculated from the intake air amount.
The air-fuel ratio of the current intake stroke can be accurately obtained, and the ignition timing can be set accurately by that amount.

According to the engine control apparatus of the present invention, the basic ignition timing is corrected in consideration of the detected operating state of the engine and the calculated intake air amount. The ignition timing can be made more accurate.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an engine for a motorcycle and a control device thereof.

FIG. 2 is a block diagram showing an embodiment of an engine control device of the present invention.

FIG. 3 is an explanatory diagram for detecting a stroke state from a phase of a crankshaft and an intake pipe pressure.

FIG. 4 is a block diagram of an intake air amount calculation unit.

FIG. 5 is a control map for obtaining a mass flow rate of intake air from an intake pipe pressure.

FIG. 6 is a block diagram of a fuel injection amount calculation unit and a fuel behavior model.

FIG. 7 is a flowchart showing a calculation process for correcting ignition timing.

FIG. 8 is a flowchart of a minor program executed in the calculation processing of FIG. 7;

FIG. 9 is a flowchart of a minor program performed in the calculation processing of FIG. 7;

FIG. 10 is a control map for setting an ignition timing used in the calculation processing of FIG. 7;

FIG. 11 is a timing chart showing the operation of the calculation processing of FIG. 7;

[Explanation of symbols]

 1 is an engine 3 is a crankshaft 4 is a piston 5 is a combustion chamber 6 is an intake pipe 7 is an intake valve 8 is an exhaust pipe 9 is an exhaust valve 10 is a spark plug 11 is an ignition coil 12 is a throttle valve 13 is an injector 15 is an engine control unit 20 is a crank angle sensor 21 is a cooling water temperature sensor 24 is an intake pipe pressure sensor 25 is an intake air temperature sensor 27 is a crank timing detecting unit (stroke state detecting unit) 28 is an intake air amount calculating unit (intake air amount calculating unit) 29 is Fuel injection amount setting unit (fuel injection amount setting unit) 31 is an ignition timing setting unit (ignition timing setting unit) 36 is a basic ignition timing calculation unit (basic ignition timing calculation unit) 35 is a fuel behavior model (fuel inflow amount calculation unit) 37 is an in-cylinder air-fuel ratio calculation unit (in-cylinder air-fuel ratio calculation unit) 38 is an ignition timing correction unit (ignition timing correction unit)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) F02D 45/00 362 F02P 5/15 B F Term (Reference) 3G022 AA03 FA03 FA06 FA07 GA01 GA02 GA05 GA06 GA07 3G084 AA03 BA09 BA13 BA15 BA17 FA02 FA07 FA11 FA20 FA26 FA33 FA38 3G301 HA01 HA06 JA12 LA01 LB02 MA01 MA13 MA18 NC02 PA01Z PA07Z PA10Z PB03Z PB05Z PE01Z PE03Z PE08Z PE09Z

Claims (4)

[Claims] 1. A phase detecting means for detecting a phase of a crankshaft of a four-cycle engine, an intake pipe pressure detecting means for detecting an intake pipe pressure in an intake pipe of the engine, and a crankshaft detected by the phase detecting means. A stroke state detecting means for detecting a stroke state based on the phase of the intake pipe pressure detected by the intake pipe pressure detecting means, and an intake air amount based on the intake pipe pressure detected by the intake pipe pressure detecting means. An intake air amount calculating means for calculating, a fuel injection amount setting means for setting a fuel injection amount to be injected from a fuel injection device, and the stroke state immediately before performing ignition based on a stroke state detected by the stroke state detecting means. The air-fuel ratio in the cylinder is calculated from the intake air amount calculated by the intake air amount calculation means and the fuel injection amount set by the fuel injection amount control means, and the ignition timing is set according to the air-fuel ratio. An engine control device comprising: ignition timing setting means for setting. 2. An ignition state setting means for detecting an operation state of the engine, wherein the ignition timing setting means calculates a basic ignition timing based on the operation state of the engine detected by the operation state detection means. Based on the timing calculation means and the state of the stroke detected by the stroke state detection means,
An in-cylinder air-fuel ratio calculating means for calculating an in-cylinder air-fuel ratio from the intake air amount calculated by the intake air amount calculating means immediately before ignition and the fuel injection amount set by the fuel injection amount setting means; 2. An ignition timing correction means for correcting the basic ignition timing set by said basic ignition timing setting means according to the cylinder air-fuel ratio calculated by the internal air-fuel ratio calculation means. An engine control device as described in the above. 3. The fuel injection amount correction means includes fuel inflow amount calculation means for calculating a fuel inflow amount flowing into a cylinder from a fuel injection amount set by the fuel injection amount setting means, and the cylinder air-fuel ratio. The calculation means calculates the air-fuel ratio in the cylinder from the fuel inflow amount in the cylinder calculated by the fuel inflow amount calculation means and the intake air amount calculated by the intake air amount calculation means. 3. The engine control device according to 2. 4. The ignition timing correcting means corrects a basic ignition timing in consideration of an engine operating state detected by the operating state detecting means and an intake air amount calculated by the intake air amount calculating means. The engine control device according to claim 2 or 3, wherein: