JP2008057547A - Engine control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely obtain an initial combustion at the engine start at which a crank pulse alone is insufficient to identify the stroke, and to increase the engine rotation speed. <P>SOLUTION: In a period from cranking start to stroke detection, fuel is injected once for each revolution of the crank shaft and prior to suction stroke (or expansion stroke), and ignition is effected once for each revolution of the crank shaft and at or around the upper dead point, whereby an initial combustion is obtained without reversing the rotation of the engine. When the stroke is detected, fuel injection and ignition are effected once for each cycle. When the engine speed does not rise above a predetermined value, ignition timing is made such that ignition is effected prior to compression upper dead point and at or around 10° on the advance angle side, whereby the engine speed quickly increase. Stroke detection is permitted after the engine speed has risen above the predetermined value so that the engine speed may stabilize. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine control device that controls an engine, and is particularly suitable for control of an engine including a fuel injection device that injects fuel.

  In recent years, as fuel injectors called injectors have become widespread, it becomes easier to control the timing of fuel injection and the amount of fuel injected, that is, the air-fuel ratio, etc., and promote higher output, lower fuel consumption, cleaner exhaust gas, etc. I was able to do it. Among these, in particular, regarding the timing of fuel injection, strictly speaking, it is general to detect the state of the intake valve, that is, generally the phase state of the camshaft, and inject fuel accordingly. However, so-called cam sensors for detecting the phase state of the camshaft are expensive, and in many cases, such as a two-wheeled vehicle, there are problems such as an increase in the size of the cylinder head, and in many cases cannot be adopted. Therefore, for example, Japanese Patent Application Laid-Open No. 10-227252 proposes an engine control device that detects the phase state of the crankshaft and the intake pressure, and detects the stroke state of the cylinder therefrom. Therefore, by using this conventional technique, the stroke state can be detected without detecting the phase of the camshaft, so that the fuel injection timing and the like can be controlled in accordance with the stroke state.

  By the way, in detecting the phase state of the crankshaft described above, teeth are formed on the outer periphery of the crankshaft itself or a member that rotates in synchronization with the crankshaft, and the approach of the teeth is detected by a magnetic sensor or the like to send a pulse signal. This pulse signal needs to be detected as a crank pulse. The crankshaft phase state is detected by, for example, numbering the crank pulses detected in this manner, but the teeth are often provided at unequal intervals for this numbering or the like. In other words, the detected crank pulse is provided with a feature as a mark. Then, the phase of the crankshaft is detected from the characterized crank pulse, and the stroke is detected by comparing the intake pressure of the same phase during two revolutions of the crankshaft, and according to the stroke and the phase of the crankshaft. The fuel injection timing and ignition timing are controlled.

However, at the start of the engine, the stroke cannot be detected unless the crankshaft is rotated at least twice. In particular, in a small displacement, single-cylinder two-wheeled vehicle or the like, the crankshaft rotation state is not stable at the initial start of the engine, and the crank pulse state is not stable, so that it is difficult to detect the stroke. And when such a stroke is not detected, a method for controlling the ignition timing and the fuel injection amount has not been proposed, which is still an unsolved problem.
The present invention has been developed to solve the above-mentioned problems, and an object of the present invention is to provide an engine control device that enables good control of the ignition timing and fuel injection amount at the start of the engine and accurate detection of the stroke. It is what.

  In order to solve the above problems, an engine control device according to the present invention is an engine having teeth provided at unequal intervals on the outer periphery of a crankshaft itself or a member that rotates synchronously with the crankshaft, and the approach of these teeth. Detected by the crankshaft phase detecting means for detecting the phase of the crankshaft from the pulse signal transmitted along with the intake pressure detecting means for detecting the intake pressure in the intake passage of the engine, and the crankshaft phase detecting means. Engine speed calculation means for calculating the engine speed based on the phase of the crankshaft; engine based on the crankshaft phase detected by the crankshaft phase detection means and the intake pressure detected by the intake pressure detection means Crank timing detection means for detecting the stroke state of the engine, and the engine speed When the engine rotational speed calculated by means output is a predetermined value or more, is characterized in that a stroke detection permitting means for permitting the detection of the engine stroke by the crank timing detecting means.

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 single cylinder four-cycle engine with a relatively small displacement, and includes a cylinder body 2, a crankshaft 3, a piston 4, a combustion chamber 5, an intake pipe (intake passage) 6, an intake valve 7, an exhaust pipe 8, An exhaust valve 9, a spark plug 10, and an ignition coil 11 are provided. In addition, a throttle valve 12 that is opened and closed according to 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 on the downstream side of the throttle valve 12. . The injector 13 is connected to a filter 18, a fuel pump 17, and a pressure control valve 16 disposed in the fuel tank 19.

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

  Here, the principle of the crank angle signal output from the crank angle sensor 20 will be described. In the present embodiment, as shown in FIG. 2a, a plurality of teeth 23 project from the outer periphery of the crankshaft 3 at substantially equal intervals, and the approach thereof is detected by a crank angle sensor 20 such as a magnetic sensor. A pulse signal is sent out by performing a special process. The pitch between the teeth 23 in the circumferential direction is 30 ° in terms of the phase (rotation angle) of the crankshaft 3, and the width in the circumferential direction of each tooth 23 is based on the phase (rotation angle) of the crankshaft 3. 10 °. However, only one place does not follow this pitch and there is a place where the pitch of the other teeth 23 is doubled. As shown by a two-dot chain line in FIG. 2a, it has a special setting in which there are essentially no teeth in a portion with teeth, and this portion corresponds to unequal intervals. Hereinafter, this portion is also referred to as a missing tooth portion.

  Therefore, the pulse signal train of each tooth 23 when the crankshaft 3 rotates at a constant speed appears as shown in FIG. 2b. FIG. 2a shows the state at the time of compression top dead center (the exhaust top dead center is the same in form), and the pulse signal immediately before this compression top dead center is shown as “0” in the drawing, Numbering (numbering) is performed up to “4” in the order of “1” for the next pulse signal and “2” for the next pulse signal. Next to the tooth 23 corresponding to the pulse signal “4” shown in the figure is the missing portion, so that it is counted as if there is a tooth, and one extra tooth is counted. " When this is repeated, this time, the missing tooth portion approaches the pulse signal of “16” shown in the figure, so that one more tooth is counted as described above, and the pulse signal of the next tooth 23 is shown as “18” in the figure. " When the crankshaft 3 is rotated twice, all four stroke cycles are completed. When the numbering is completed up to “23” in the figure, the pulse signal of the next tooth 23 is again numbered “0” in the figure. In principle, the compression top dead center should be immediately after the pulse signal of the tooth 23 numbered “0”. Thus, the detected pulse signal train or a single pulse signal thereof is defined as a crank pulse. If the stroke is detected as described later based on the crank pulse, the crank timing can be detected. The teeth 23 are exactly the same even when provided on the outer periphery of a member that rotates in synchronization with the crankshaft 3.

  On the other hand, the engine control unit 15 is constituted by a microcomputer not shown. FIG. 3 is a block diagram showing an embodiment of engine control calculation processing performed by a microcomputer in the engine control unit 15. In this calculation process, an engine speed calculation unit 26 that calculates an engine speed from the crank angle signal, and a crank timing detection unit 27 that detects crank timing information, that is, a stroke state, from the crank angle signal and the intake pressure signal. The engine speed calculated by the engine speed calculator 26 is read, the stroke detection permission information is output to the crank timing detector 27, and the stroke detection information by the crank timing detector 27 is captured. The crank timing information detected by the stroke detection permission unit 29 and the crank timing detection unit 27 to be output is read, and the intake air temperature signal, the coolant temperature (engine temperature) signal, the intake pipe pressure signal, and the engine speed are read. The cylinder from the engine speed calculated by the calculation unit 26 An in-cylinder air mass calculation unit 28 that calculates an air mass (intake air amount), and a target air-fuel ratio calculation unit that calculates a target air-fuel ratio from the engine speed calculated by the engine speed calculation unit 26 and the intake pressure signal 33, the target air-fuel ratio calculated by the target air-fuel ratio calculation unit 33, the intake pressure signal, the cylinder air mass calculated by the cylinder air mass calculation unit 28, and the stroke detection permission unit 29 A fuel injection amount calculation unit 34 for calculating a fuel injection amount and fuel injection timing from the stroke detection information and the cooling water temperature signal, and the crank timing information detected by the crank timing detection unit 27 are read, and the fuel injection amount calculation unit An injection pulse output for outputting an injection pulse corresponding to the fuel injection amount and fuel injection timing calculated at 34 to the injector 13 30, the ignition timing is calculated from the engine speed calculated by the engine speed calculator 26, the target air-fuel ratio set by the target air-fuel ratio calculator 33, and the stroke detection information output from the stroke detection permission unit 29. The crank timing information detected by the ignition timing calculation unit 31 to be calculated and the crank timing detection unit 27 is read, and an ignition pulse corresponding to the ignition timing set by the ignition timing calculation unit 31 is directed toward the ignition coil 11. And an ignition pulse output unit 32 for outputting.

  The engine speed calculator 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. Specifically, the instantaneous value of the engine speed obtained by dividing the phase between the adjacent teeth 23 by the corresponding crank pulse detection time and the average value of the engine speed composed of the moving average value are calculated.

  The crank timing detection unit 27 has the same configuration as the stroke discriminating apparatus described in Japanese Patent Laid-Open No. 10-227252 described above, thereby detecting the stroke state of each cylinder as shown in FIG. 4, for example. It is output as crank timing information. That is, in a four-cycle engine, the crankshaft and the camshaft always rotate with a predetermined phase difference. For example, when a crank pulse is read as shown in FIG. The second illustrated "9" or "21" crank pulse is either the exhaust stroke or the compression stroke. As is well known, since the exhaust valve is closed and the intake valve is closed in the exhaust stroke, the intake pressure is high, and at the beginning of the compression stroke, the intake pressure is low because the intake valve is still open, or the intake valve is closed. However, the intake pressure is low in the preceding intake stroke. Therefore, the crank pulse “21” in the figure when the intake pressure is low indicates that it is in the compression stroke, and the compression top dead center is immediately after the crank pulse “0” in the figure is obtained. If any one of the stroke states can be detected in this way, the current stroke state can be detected more finely by interpolating between the strokes at the rotational speed of the crankshaft.

  The stroke detection permission unit 29 outputs the stroke detection permission information for the crank timing detection unit 27 in accordance with the arithmetic processing shown in FIG. As described above, at least two revolutions of the crankshaft are required to detect the stroke from the crank pulse. During this time, it is necessary that the crank pulse including the missing portion is stable. However, in a relatively small displacement, single-cylinder engine as in the present embodiment, the rotational state of the engine is not stable during so-called cranking at the time of starting. Therefore, the engine rotation state is determined by the arithmetic processing of FIG. 5 and the stroke detection is permitted.

The arithmetic processing in FIG. 5 is executed with, for example, the input of the crank pulse as a trigger. In this flowchart, there is no particular communication step, but information obtained by the arithmetic processing is updated and stored in the storage device as needed, and information and programs necessary for the arithmetic processing are read out from the storage device as needed. The
In this calculation process, first, in step S11, the average value of the engine speed calculated by the engine speed calculator 26 is read.
Next, the process proceeds to step S12, and it is determined whether or not the average value of the engine speed read in step S11 is equal to or higher than a predetermined speed detection permission predetermined speed equal to or higher than the speed corresponding to the initial explosion. Determination is made, and if the average value of the engine speed is greater than or equal to the stroke detection permission predetermined speed, the process proceeds to step S13; otherwise, the process proceeds to step S14.

In step S13, the process returns to the main program after outputting information indicating that the stroke detection is permitted.
In step S14, information indicating that the stroke detection is not permitted is output, and then the process returns to the main program.
According to this calculation process, since the stroke detection is permitted after the average value of the engine speed becomes at least the stroke detection permission predetermined rotation speed equal to or higher than the rotation speed equivalent to the time of the first explosion, the crank pulse is stabilized, Accurate stroke detection is possible.

  As shown in FIG. 6, the cylinder air mass calculation unit 28 displays a three-dimensional map for calculating the cylinder air mass from the intake pressure signal and the engine speed calculated by the engine speed calculation unit 26. I have. This three-dimensional map of the air mass in the cylinder only needs to measure the air mass in the cylinder when the intake pressure is changed while actually rotating the engine at a predetermined speed, and is measured by a relatively simple experiment. Yes, so creating a map is easy. If there is an advanced engine simulation, it is possible to create a map using it. Since the cylinder air mass varies depending on the engine temperature, the cylinder air mass may be corrected using the cooling water temperature (engine temperature) signal.

  As shown in FIG. 7, the target air-fuel ratio calculation unit 33 includes a three-dimensional map for calculating a target air-fuel ratio from the intake pressure signal and the engine speed calculated by the engine speed calculation unit 26. Yes. This three-dimensional map can be set on a desk to a certain extent. The air-fuel ratio is generally correlated with torque, and if the air-fuel ratio is small, that is, if there is a lot of fuel and little air, the torque will increase, but the efficiency will decrease. Conversely, if the air-fuel ratio is large, that is, if the fuel is low and the air is high, the torque is reduced, but the efficiency is improved. A state in which the air-fuel ratio is small is rich, and a state in which the air-fuel ratio is large is called lean. The leanest state is called a so-called ideal air-fuel ratio or stoichiometric and is the air-fuel ratio at which gasoline is completely burned, that is, 14. 7.

The engine speed is an operating state of the engine. Generally, the air-fuel ratio is increased on the high rotation side and decreased on the low rotation side. This is to increase the torque response on the low rotation side and to increase the rotation response on the high rotation side. The intake pressure is an engine load condition such as the throttle opening, and generally the engine load is large, that is, when the throttle opening is large and the intake pressure is large, the air-fuel ratio is decreased and the engine load is small. The air-fuel ratio is increased when the throttle opening is small and the intake pressure is small. This is because torque is emphasized when the engine load is large, and efficiency is emphasized when the engine load is small.
Thus, the target air-fuel ratio is a numerical value whose physical meaning is easy to grasp. Therefore, the target air-fuel ratio can be set to some extent according to the required engine output characteristics. Of course, it goes without saying that tuning may be performed in accordance with the engine output characteristics of the actual vehicle.

  The target air-fuel ratio calculating unit 33 detects a transition period of the engine operating state from the intake pressure signal, specifically, an acceleration state or a deceleration state, and corrects the target air-fuel ratio accordingly. 29. For example, as shown in FIG. 8, since the intake pressure is also a result of the throttle operation, it can be seen that when the intake pressure increases, the throttle is opened and acceleration is required, that is, an acceleration state. When such an acceleration state is detected, the target air-fuel ratio is temporarily set to the rich side, for example, and then returned to the original target air-fuel ratio. For returning to the target air-fuel ratio, an existing method can be used, for example, by gradually changing the weighted average weighting coefficient between the air-fuel ratio set to the rich side in the transition period and the original target air-fuel ratio. Conversely, when a deceleration state is detected, it may be set leaner than the original target air-fuel ratio, and efficiency may be emphasized.

The fuel injection amount calculation unit 34 calculates and sets the fuel injection amount and fuel injection timing at the time of engine start and normal operation according to the arithmetic processing shown in FIG. The arithmetic processing in FIG. 9 is executed using, for example, the input of the crank pulse as a trigger. In this flowchart, there is no particular communication step, but information obtained by the arithmetic processing is updated and stored in the storage device as needed, and information and programs necessary for the arithmetic processing are read out from the storage device as needed. The
In this calculation process, first, in step S21, the process detection information output from the process detection permission unit 29 is read.

Next, the process proceeds to step S22, where it is determined whether or not the stroke detection by the crank timing detection unit 27 is incomplete. If the stroke detection is not complete, the process proceeds to step S23. Control goes to step S24.
In step S23, it is determined whether or not the fuel injection number counter n is “0”. If the fuel injection number counter n is “0”, the process proceeds to step S25; The process proceeds to S26.
In the step S25, it is determined whether or not the fuel injection is the third and subsequent fuel injections from the start of the engine start. If the fuel injection is the third and subsequent fuel injections, the process proceeds to step S27. Goes to step S28.

In the step S27, the intake pressure at a predetermined crank angle set between two rotations of the crankshaft, in the present embodiment at the crank pulse "6" or "18" shown in FIGS. After reading from an intake pressure storage unit (not shown) and calculating an intake pressure difference between the two, the process proceeds to step S29.
In the step S29, it is determined whether or not the intake pressure difference calculated in the step S28 is not less than a predetermined value, for example, so that the stroke can be identified to some extent, and the intake pressure difference is not less than the predetermined value. If not, the process proceeds to step S30. If not, the process proceeds to step S28.

In step S30, the total fuel injection amount is calculated based on the smaller one of the intake pressures at a predetermined crank angle between the two rotations of the crankshaft read in step S27, and then the process proceeds to step S31. Transition.
On the other hand, in step S28, the cooling water temperature, that is, the engine temperature is read. For example, the fuel injection amount is increased as the cooling water temperature is lower, and the total fuel injection amount corresponding to the cooling water temperature is calculated. The process proceeds to S31. The total fuel injection amount calculated in step S28 or step S30 means a fuel injection amount that should be injected in one cycle, that is, once every two rotations of the crankshaft, before the intake stroke. Accordingly, if the stroke is already detected and the fuel injection amount corresponding to the coolant temperature is injected only once before the intake stroke, the engine rotates appropriately according to the coolant temperature, that is, the engine temperature.

In step S31, half of the total fuel injection amount set in step S30 is set as the current fuel injection amount, and at each rotation, that is, every crankshaft rotation, a predetermined crank angle, in this embodiment, After the crank pulse falling time of “10” or “22” shown in FIGS. 2 and 4 is set as the fuel injection timing, the process proceeds to step S32.
In step S32, the fuel injection number counter “1” is set, and then the process returns to the main program.

On the other hand, in step S24, it is determined whether or not the previous fuel injection is immediately before the intake stroke. If the previous fuel injection is immediately before the intake stroke, the process proceeds to step S33. If not, step S26 is performed. Migrate to
In step S26, the previous fuel injection amount is set to the current fuel injection amount, and a predetermined crank angle is set to the fuel injection timing for each rotation, that is, for each rotation of the crankshaft, as in step S31. Then, the process proceeds to step S34.
In step S34, the fuel injection number counter is set to “0” and then the process returns to the main program.

In step S33, the fuel injection amount and fuel injection timing during normal operation according to the target air-fuel ratio, cylinder air mass, and intake pressure are set, and then the process proceeds to step S35. Specifically, for example, the in-cylinder air mass calculation unit 28 divides the in-cylinder air mass by the target air-fuel ratio calculated by the target air-fuel ratio calculation unit 33 to obtain the required fuel mass in the cylinder. Therefore, the fuel injection time can be obtained by multiplying the flow rate characteristic of the injector 13, for example, and the fuel injection amount and the fuel injection timing can be calculated therefrom.
In step S34, the fuel injection number counter is set to “0” and then the process returns to the main program.

  In this calculation process, when the stroke detection by the crank timing detection unit 27 is not completed, the total fuel injection amount that can properly rotate the engine if it is injected once in one cycle before the intake stroke. When the engine starts, only half of the required fuel is drawn in the first intake stroke from the start of cranking, as will be described later. There is a possibility, but if it is ignited at or near the compression top dead center, although it is weak, it is possible to reliably obtain an explosion and start the engine. Of course, if the required fuel is inhaled in the first intake stroke from the start of cranking, that is, if the fuel injected once per crankshaft rotation can be inhaled twice, sufficient explosive power is achieved. It is possible to reliably start the engine.

  Even when the stroke is detected, if the previous fuel injection is not immediately before the intake stroke, for example, before the exhaust stroke, only half of the required fuel injection amount is still injected. Therefore, by injecting the same fuel injection amount as the previous time again, necessary fuel is taken in in the next intake stroke, and the engine can be operated with sufficient explosive force.

  Further, when the stroke detection is not completed, a predetermined crank angle between two rotations of the crankshaft, specifically, a crank pulse of “6” or “18” shown in FIGS. , That is, the intake pressure of the intake stroke or the expansion stroke, and the difference between the intake pressures is calculated. As described above, if the throttle valve is not opened suddenly, there is a corresponding pressure difference between the intake pressure in the intake stroke and the intake pressure in the expansion stroke, so the calculated intake pressure difference can be detected by the stroke. If it is above a certain value, it is assumed that the smaller one of the intake pressures is the intake pressure of the intake stroke, and the total fuel is determined according to the intake pressure, that is, the intake pressure corresponding to the throttle opening to some extent. By setting the injection amount, it is possible to obtain an increase in engine rotation according to the throttle opening.

On the other hand, the difference in intake pressure at a predetermined crank angle between the two rotations of the crankshaft is less than a predetermined value, or at the time of fuel injection immediately after the start of starting, the total fuel injection amount corresponding to the coolant temperature, that is, the engine temperature is set. Accordingly, it is possible to reliably start the engine against at least friction.
The ignition timing calculation unit 31 calculates and sets the ignition timing at the time of engine start and normal operation according to the arithmetic processing shown in FIG. The arithmetic processing in FIG. 10 is executed with the input of the crank pulse as a trigger. In this flowchart, there is no particular communication step, but information obtained by the arithmetic processing is updated and stored in the storage device as needed, and information and programs necessary for the arithmetic processing are read out from the storage device as needed. The

In this calculation process, first, in step S41, the process detection information output from the process detection permission unit 29 is read.
Next, the process proceeds to step S42, where it is determined whether or not the stroke detection by the crank timing detection unit 27 is incomplete. If the stroke detection is not completed, the process proceeds to step S47. The process proceeds to step S44.

  In step S47, for example, when the engine starts, before the start of cranking and before the explosive force of the first explosion is obtained, the initial ignition timing is increased every crankshaft rotation because the engine speed is low and unstable. Return to the main program after setting the dead point (regardless of compression or exhaust), that is, when the crank pulse falls at “0” or “12” shown in FIG. To do. Note that the ± crankshaft rotation angle 10 ° is a value that takes into account electrical or mechanical response, and is substantially the crank pulse “0” or “12” shown in FIG. 2 or FIG. Ignition at the same time of falling.

In step S44, the process proceeds to step S48 if the average value of the engine speed is greater than or equal to a predetermined value. If the average value of the engine speed is greater than or equal to the predetermined value, the process proceeds to step S48. Migrate to
In step S46, for example, at the time of starting the engine, after obtaining the explosive force by the first explosion, assuming that the engine speed is somewhat high (but the engine speed is not stable), the late ignition timing is 1 cycle. Once at the compression top dead center, the advance side is set to 10 °, that is, when the crank pulse rises to “0” shown in FIG. 3 or FIG. . Note that the ± crankshaft rotation angle 10 ° is a value that takes into account electrical or mechanical response, and is substantially the crank pulse “0” or “12” shown in FIG. 2 or FIG. Ignition is performed at the same time as the rise.

In step S48, the normal ignition timing is set once per cycle, and then the process returns to the main program. For example, in general, in normal ignition, the torque is fullest at a slight advance side from the top dead center, so the ignition timing is adjusted according to the driver's acceleration intention reflected in the intake pressure, centered on the ignition timing To do.
In this calculation process, at the start of cranking before the first explosion when the stroke detection is not completed, that is, at the start of the operation, the crankshaft 1 is reliably rotated to start the engine together with the fuel injection for each rotation of the crankshaft. The reverse rotation of the engine is prevented by setting the vicinity of the top dead center at each ignition as an ignition timing. Further, even after the stroke is detected, until the engine speed reaches a predetermined value or more, the engine is set by setting the vicinity of the advance angle side 10 ° before the relatively torqueful compression top dead center as the late start ignition timing. Stabilize the rotation speed higher.

  As described above, in the present embodiment, the cylinder air mass is calculated from the intake pressure and the engine operating state according to the three-dimensional map of the cylinder air mass stored in advance, and from the intake pressure and the engine operating state in advance. According to the stored target air-fuel ratio map, the fuel injection amount can be calculated by calculating the target air-fuel ratio and dividing the cylinder air mass by the target air-fuel ratio, so that the control is easy and accurate. At the same time, the in-cylinder air mass map is easy to measure and the target air-fuel ratio map is easy to set. Further, a throttle sensor such as a throttle opening sensor or a throttle position sensor for detecting the engine load is unnecessary.

In addition, by detecting that the intake pressure is in a transitional state such as acceleration or deceleration and correcting the target air-fuel ratio, the engine output characteristics during acceleration or deceleration are simply set according to the target air-fuel ratio map. It can be changed from what is done to what the driver demands or something close to the driver's feeling.
Further, by detecting the engine speed from the phase of the crankshaft, the engine speed can be easily detected, and for example, if the stroke state is detected from the phase of the crankshaft instead of the cam sensor, An expensive and large cam sensor can be eliminated.

  Thus, in the present embodiment that does not use a cam sensor, it is important to detect the phase and stroke of the crankshaft. However, in the present embodiment in which the stroke is detected only from the crank pulse and the intake pressure, the stroke cannot be detected at least unless the crankshaft is rotated twice. However, I don't know which stroke the engine will be stopped. In other words, it is not known from which stroke cranking starts. Therefore, in the present embodiment, fuel is injected at a predetermined crank angle for each rotation of the crankshaft using the crank pulse until the stroke is detected from the start of cranking, and the compression is also increased for each rotation of the crankshaft. Ignition near dead center. In addition, after the stroke is detected, fuel injection that can achieve the target air-fuel ratio corresponding to the throttle opening is performed once per cycle, but until the engine speed reaches a predetermined value or more, the crank pulse Is used to ignite in the vicinity of 10 ° on the advance side before compression top dead center where torque is easily generated.

  FIG. 12 shows that the initial explosion was obtained by the fuel injection and ignition timing control as described above, and the engine (crankshaft) rotation speed, fuel injection pulse, ignition pulse when the explosive power of the initial explosion was relatively small. It shows the change over time. As described above, until the first explosion is obtained and the average value of the engine speed becomes equal to or higher than the predetermined rotation speed for detecting the stroke, the ignition pulse is “0” shown in FIG. 3 or “12” shown in FIG. ”(Numbering at this time is not accurate) is output at the falling edge of the crank pulse, and the fuel injection pulse is“ 10 ”or“ 22 ”shown in FIG. The numbering is not accurate) and is output at the falling edge of the crank pulse. Incidentally, the ignition is set at the end of the ignition pulse, that is, at the fall, and the fuel injection is ended at the end of the fuel injection pulse, that is, at the fall.

In addition, the first and second fuel injections shown in the figure follow the total fuel injection amount set based on the coolant temperature, that is, the engine temperature as described above. During this period, the crank pulse “18” corresponding to the intake stroke is used. the intake pressure P ₁ of the crank pulse "6" corresponding to the intake air pressure P ₀ and the expansion stroke resulting in, and since the intake air pressure difference between the two was the stroke detectable above a predetermined value, the third and fourth This fuel injection follows the lower fuel intake pressure, that is, the total fuel injection amount set based on the intake pressure P ₀ of the crank pulse “18” corresponding to the intake stroke.

  Because this fuel injection and ignition control resulted in a weak initial explosion, the average value of the engine speed gradually increases, and the process detection is permitted when the engine speed reaches the predetermined process speed. As described above, the stroke detection is performed by comparing the previous intake pressure at the same crank angle. At this time, as a result of the stroke detection, the previous fuel injection was immediately before the intake stroke, and thereafter, the fuel that achieves the target air-fuel ratio was injected once per cycle at an ideal timing. On the other hand, after the stroke is detected, the ignition timing is also performed only once per cycle. However, since the cooling water temperature has not yet reached the predetermined temperature and the idling engine speed has not been stabilized, the ignition timing is compression dead. Before the point, the ignition pulse is output at the advance side of 10 °, that is, when the crank pulse rises to “0” shown in FIG. As a result, the engine speed increases rapidly thereafter.

  FIG. 13 shows changes over time in engine (crankshaft) rotation speed, fuel injection pulse, and ignition pulse when a large explosive force is obtained in the first explosion as a result of similar fuel injection and ignition control during cranking. It is a thing. When the first explosion is strong in this way, the average value of the engine speed increases rapidly, and the stroke detection is permitted for a short period of time, and the stroke detection is allowed to exceed the predetermined rotation speed. At this time, as a result of the stroke detection, since the previous fuel injection was not immediately before the intake stroke, specifically, the expansion stroke, the same fuel injection amount is again injected at the same crank angle as the previous stroke, and the subsequent intake stroke The ideal amount of fuel is taken in during the stroke, which makes it possible to stabilize the engine start.

  Thus, in this embodiment, until the stroke is detected, fuel is injected at a predetermined crank angle for each rotation of the crankshaft and ignition is performed in the vicinity of the compression top dead center for each rotation of the crankshaft. Even if it is weak, a reliable initial explosion can be obtained, and reverse rotation of the engine can be prevented. That is, if ignition is performed on the advance side of the compression top dead center before the first explosion is obtained, the engine may reversely rotate. Further, after the stroke is detected, fuel injection and ignition are performed once in one cycle. When this ignition is performed before compression top dead center and in the vicinity of 10 ° on the advance side, the engine speed can be quickly raised.

  If fuel injection and ignition are performed once per cycle, that is, once every two rotations of the crankshaft before the stroke is detected, the fuel injection is after intake or the ignition is not at the top dead center of compression. In addition, there is no reliable first explosion. That is, there are cases where the engine starts smoothly and does not start. In addition, if fuel injection is performed once per crankshaft rotation after the stroke is detected, fuel must be continuously injected in a two-wheeled vehicle with a high engine speed range, and the dynamic range of the injector is restricted. It will be. Moreover, it is a waste of energy to continue ignition once per rotation of the crankshaft even after the stroke is detected.

Although the intake pipe injection type engine has been described in detail in the above embodiment, the engine control device of the present invention can be similarly applied to a direct injection type engine.
Although the single cylinder engine has been described in detail in the above embodiment, the engine control device of the present invention can be similarly applied to a so-called multi-cylinder engine having two or more cylinders.
The engine control unit can be replaced with various arithmetic circuits instead of the microcomputer.

It is a schematic block diagram of the engine for motorcycles and its control apparatus. It is explanatory drawing of the principle which sends a crank pulse with the engine of FIG. It is a block diagram which shows one Embodiment of the engine control apparatus of this invention. It is explanatory drawing which detects a stroke state from the phase of a crankshaft, and intake pressure. It is a flowchart which shows the arithmetic processing performed in the stroke detection permission part of FIG. It is a map for the cylinder air mass calculation memorize | stored in the cylinder air mass calculation part. 3 is a map for calculating a target air-fuel ratio stored in a target air-fuel ratio calculation unit. It is operation | movement explanatory drawing of a transition period correction | amendment part. It is a flowchart which shows the arithmetic processing performed by the fuel injection amount calculation part of FIG. It is a flowchart which shows the arithmetic processing performed in the ignition timing calculation part of FIG. It is explanatory drawing of the ignition timing set in FIG. FIG. 4 is an operation explanatory diagram at the time of engine start by the arithmetic processing of FIG. 3. FIG. 4 is an operation explanatory diagram at the time of engine start by the arithmetic processing of FIG. 3.

Claims (7)

  An engine having teeth provided at unequal intervals on the outer periphery of the crankshaft itself or a member that rotates in synchronization with the crankshaft, and detecting the phase of the crankshaft from a pulse signal transmitted as the teeth approach Crankshaft phase detection means, intake pressure detection means for detecting intake pressure in the intake passage of the engine, and engine speed for calculating engine speed based on the phase of the crankshaft detected by the crankshaft phase detection means A calculating means; a crank timing detecting means for detecting a stroke state of the engine based on a crankshaft phase detected by the crankshaft phase detecting means and an intake pressure detected by the intake pressure detecting means; andthe engine speed. When the engine speed calculated by the calculating means is greater than or equal to a predetermined value To the crank timing detecting section an engine control apparatus characterized by comprising a stroke detection permitting means for permitting the detection of the engine stroke by.   Ignition timing calculation means for setting the ignition timing based on the engine speed calculated by the engine speed calculation means is provided, and the ignition timing calculation means does not allow the stroke detection permission means to detect the engine stroke. 2. The engine control device according to claim 1, wherein a predetermined pulse signal corresponding to a top dead center is set as an ignition timing once for each rotation of the crankshaft for one cylinder of the engine.   The fuel injection amount calculating means for setting the fuel injection amount and the fuel injection timing based on the engine stroke state detected by the crank timing detecting means, the fuel injection amount calculating means, wherein the stroke detection permitting means includes the engine stroke detecting means. 2. The engine according to claim 1, wherein a predetermined crankshaft phase is set to a fuel injection timing for each rotation of the crankshaft for one cylinder of the engine when detection of the engine is not permitted. Control device.   When the stroke detection permission unit does not permit the detection of the engine stroke, the fuel injection amount calculation unit supplies, to one cylinder of the engine, half the fuel amount necessary for one stroke of the cylinder. The engine control device according to claim 3, wherein the engine control device is set as a fuel injection amount.   The engine control device according to claim 1, wherein the predetermined value of the engine speed is set to a value when an explosion force is obtained by an initial explosion.   The engine control apparatus according to claim 1, wherein an average value of the engine speed is used as the engine speed.   The engine control apparatus according to claim 1, wherein the engine is a single cylinder engine.

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