JP2563100B2 - Engine controller - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control device, and more particularly to a device for correcting an engine control amount for suppressing knocking according to an octane number of fuel used during acceleration.

<Prior art> As is well known, when the engine is accelerated, the air-fuel ratio becomes lean, and knocking is likely to occur due to factors such as a control delay, so the ignition timing should be set to be later than in steady state. Has been. On the other hand, it is well known that the knocking limit at which knocking occurs in an engine depends on the octane number of the fuel used by the engine.

Therefore, the following problems occur in the control in which the ignition timing of the engine is focused only on the operating state of the engine and is simply changed between the acceleration time and the steady time.

That is, for example, if the ignition timing is set to match a normal octane fuel (hereinafter referred to as regular), the ignition timing is retarded more than necessary than the knocking limit when a high octane fuel (hereinafter referred to as high octane) is used. It becomes a condition and causes an output loss.

Further, if the ignition timing is set in accordance with the high octave, when the regular is used, the retard amount of the ignition timing is insufficient and knocking occurs.

Therefore, as disclosed in, for example, Japanese Patent Application Laid-Open No. 58-143169, engine control is performed in which the ignition timing is set on the high-octane fuel side and the ignition timing is shifted to the regular side when knocking occurs. It is considered that the above problem can be solved by combining with the control of the ignition timing at the time of acceleration, but there is a problem described below also in such engine control.

<< Problems to be Solved by the Invention >> That is, in the combination of the control disclosed in the above publication and the control during acceleration, the knocking limit varies depending on the air-fuel ratio, even if the knocking limit varies depending on the fuel used. Moreover, as the air-fuel ratio shifts from rich to lean, the interval between the knocking limit between regular and high-octane tends to open, and the slope of the curve obtained by the relationship between the knocking limit and the air-fuel ratio becomes high-octane and regular. However, there is a problem that a simple shift of the ignition timing cannot sufficiently cope with this.

<< Means for Solving Problems >> In order to achieve the above object, according to the present invention, an engine control device includes a knocking detection means for detecting knocking of the engine, and an engine control amount for suppressing knocking at the time of knocking detection. Based on the acceleration request change degree detection means, and a fuel component detection means for detecting the octane number of the fuel supplied to the engine, an acceleration request change degree detection means for detecting the acceleration request change degree, An acceleration determination means for determining that the vehicle is accelerating when the degree of change is equal to or greater than a predetermined value, and a fuel amount increasing means for increasing the amount of fuel supplied to the engine at the time of acceleration. In response to the above output, the fuel amount is increased by the fuel increasing means as the octane number becomes smaller during acceleration.

<Operation> According to the engine control device having the above configuration, the fuel amount is increased when the engine is accelerating when the degree of change in acceleration required by the occupant is equal to or greater than the predetermined value, and the octane number is corrected by the octane number of the fuel used. Since the amount of increase increases as the value decreases, the optimum amount of acceleration can be increased according to the octane number of the fuel used, and knocking can be prevented and fuel consumption can be improved.

<Example> Hereinafter, a preferred example of the present invention will be described in detail with reference to the accompanying drawings.

1 to 3 show a first embodiment of an engine control device according to the present invention.

FIG. 1 shows the overall configuration of the device of this embodiment. An intake valve 14 and an exhaust valve 16 are provided in a combustion chamber 12 formed by a cylinder block 10a and a cylinder head 10b of an engine 10.
And a spark plug 18 are arranged.

The combustion chamber 12 has an intake passage 20 that is opened and closed by an intake valve 14.
And an exhaust passage 22 that is opened and closed by an exhaust valve 16 are connected to each other, and an air flow sensor 24 for measuring an intake air amount (Q) and an intake air amount (Q) are measured in the intake passage 20 from an upstream side thereof. A throttle valve 26 to be controlled and a fuel injection valve 28 for injecting fuel into the combustion chamber 12 are sequentially arranged.

The exhaust passage 22 is provided with an O2 sensor 30 that measures the amount of oxygen (O2) in the exhaust gas, and a knock sensor 32 that detects knocking of the engine 10 is provided in the cylinder block 10.
It is provided in a.

The ignition plug 36 receives an ignition signal from the control unit 34 and generates an ignition coil 36 that generates a high voltage.
Is connected to a distributor 38 that distributes the high voltage of the ignition coil 36 to the ignition plugs 18 of the respective cylinders, and the rotation angle of the distributor 38 is input to the control unit 34 as a crank angle signal.

As the control unit 34, a microcomputer including Cpu, ROM, RAM, I / F, etc. is used, and controls the ignition timing of the engine 10 according to the control flow shown in FIG. 2 or FIG.

FIG. 2 shows the main routine of the control performed by the control unit 36. When the control starts,
First, in step S1, the unit 36 is initialized.

In the following step S2, the rotation speed Ne is calculated from the cycle T0 of the crank angle signal, and the intake air amount Qa is input from the output value of the air flow sensor 24 in step S3.

In step S4, the filling amount Ce is calculated based on Ne and Qa obtained in steps SS2 and S3, and the filling amount Ce is multiplied by the coefficient KI in step S5 to obtain the basic injection amount TB by the fuel injection valve 28.
Is calculated.

In step S6, the basic ignition timing θB is calculated from the values of the rotation speed Ne and the charging amount Ce based on a predetermined map using these values as a function.

In the next steps S7 and S8, it is judged whether or not the filling amount Ce and the rotation speed Ne are respectively larger than predetermined values (CeER, NeER), and both Ce and Ne are larger than CeER, NeER. If it is determined that it is smaller, the output value Vo of the O2 sensor 30 is input in step S9, and Vo is a predetermined value (0.5V) in step S10.
If Vo is smaller than 0.5 V, the air-fuel ratio is on the lean side, so in step S11 the feedback coefficient is increased, while Vo
Is larger than 0.5 V, the air-fuel ratio is on the rich side, and therefore, the feedback coefficient is reduced in step S12, and the enrichment coefficient CER is initialized in step S13.

In steps S7 and S8, Ce and Ne are CeER and N, respectively.
If it is determined that it is larger than eER, the current operating state is in the enriched zone, so after initializing the feedback coefficient in step S13, C in step S14.
The enrichment coefficient CER is calculated from the map of e and Ne.

When the feedback control or the enrichment control is completed according to the above engine operating state, step S15
From the current filling amount Ce obtained in step S4 in
Ce * is subtracted to obtain the change amount ΔCe of the filling amount, and in the next step S16, the previous filling amount Ce * is updated as Ce.

Here, the change amount ΔCe of the filling amount Ce corresponds to the acceleration of the engine 10, and by calculating the change amount ΔCe, the acceleration request change degree of the occupant is detected. Then, in step S17, it is determined whether or not ΔCe is larger than a predetermined value ΔCACC, and if ΔCe is larger than a predetermined value ΔCACC, it means that the vehicle is accelerating. Therefore, in step S18, the acceleration retardation amount θACC is calculated. .

That is, in this embodiment, various sensors such as the air flow sensor 24 and the distributor 38 that contribute to the calculation of the change amount ΔCe and the control unit 34 constitute acceleration request change degree detection means and acceleration time determination means.

The acceleration retardation amount θACC is calculated by adding the acceleration basic retardation amount θACCB to the third value.
It is obtained by multiplying the average value θR of the knock feedback retard angle amount that reflects the octane number of the used fuel obtained by the control flow shown in the figure.

On the other hand, when ΔCe is smaller than ΔCACC and it is determined that the vehicle is not accelerating in step S17, it is determined in step S18 whether or not the acceleration retardation amount θACC is larger than 0, and θACC is accelerated to be larger than 0. On the other hand, when the ignition timing is retarded, ΔCACC is subtracted from θACC in step S19, it is determined in step S20 whether θACC is smaller than 0, and θACC is determined by this comparison. If it is 0 or more, the process proceeds to step S22 and θACC
Is gradually attenuated, and when θACC becomes smaller than 0, θACC is set to 0 in step S21.

After the calculation of the acceleration retardation amount θACC during acceleration or the attenuation of θACC during non-acceleration, the battery voltage VB is input in step S22, and the invalid injection time TV is obtained from the VB table in step S23. After that, the final injection amount Ti is obtained in step S24, and the process returns to step S2.

FIG. 3 shows the knock feedback retardation amount θR used when calculating the acceleration retardation amount θACC in step S18,
Further, an interrupt routine for calculating the final ignition timing and outputting the result to the spark plug 18 is shown.

This interrupt routine executes the specified crank angle (ATDC
It is executed every 60 degrees, and when the control starts, the step
The interrupt time t2 is input in S30, the previous interrupt time t1 is subtracted from t2 in step S31, and the cycle T0 used in step S2 shown in FIG. 2 is calculated. The interrupt time t1 is updated to t2 to obtain the cycle.

Next, at step S33, it is judged if the filling amount Ce obtained at step S4 of FIG. 2 is larger than a predetermined value CeKC.

The predetermined value CeKC used here is set to a value at which there is almost no risk of knocking with respect to regular when the filling amount is less than or equal to this value.

When it is determined that Ce is larger than CeKC in step S33, the output value (knock intensity Ik) of the knock sensor 32 is input in step S34, and it is determined whether or not the value of Ik is larger than 0 in subsequent step S35. To be done.

If it is determined in step S35 that IK is greater than 0, in step S36 a new knock feedback is obtained by adding the value obtained by multiplying the current knock feedback retard angle amount θR by the knocking intensity IK by a predetermined constant KR. Delay angle θR
Set.

If it is determined that IK is smaller than 0 in step S35, the small angle ΔθR is subtracted from the current knock feedback delay angle amount θR in step S37 to obtain a new knock feedback delay angle amount, and step S38 Then, it is determined whether or not the value is smaller than 0.

If it is determined that θR is smaller than 0 in step S38, θR is set to 0 in step S39.

That is, in steps S34 to S36 described above, if the engine 10 is knocking at the current ignition retard amount, the knock feedback retard amount θR is corrected to be large, whereas if the engine 10 is not knocking, the knock feedback retard amount θR is corrected in step S37. When the knock feedback delay angle amount θR is advanced by a small angle and the knock feedback delay angle amount θR becomes 0 or less, the output is decreased due to the relationship that the base delay angle amount θB is set at the maximum output. Since it will come, we are trying not to make θR less than 0.

When a new knock feedback retardation amount θR is set in steps S36 and 37, it is determined in subsequent steps S40 to S43 whether the current operating state of the engine 10 is in the octane number determination zone.

In this example, the upper and lower limits of the filling amount (CeoCTH, CeoCT
L) and the upper and lower limit values of the rotation speed (NeoCTH, NeoCTL) are set, and if the current filling amount Ce and the rotation speed Ne of the engine 10 are within the zone defined by these upper and lower limit values, Step
In S44, a weighted average is obtained from a plurality of knock feedback delay angle amounts θR, and an average knock feedback delay angle amount θR is calculated.

Average knock feedback delay angle θ obtained here
For R, the knock feedback retard angle amount θR is the knock intensity I.
Depending on whether or not K is large or small, it is increased / decreased each time the interrupt routine is executed, and since it is a weighted average of that value, it reflects the octane number of the fuel used in the engine 10.

That is, when compared with the same filling amount, if the octane number is low and the regular octane number is regular, knocking will occur unless the retard amount θR is increased, but θR is the magnitude of the knock strength IK. The value of θR is corrected by the presence or absence, and as a result, the knocking limit that varies depending on the used fuel (high octane, regular) is detected, and if the average value is calculated, the type of used fuel, that is, the octane number of used fuel, is indirectly determined. Can be detected.

If it is determined in step S33 that the filling amount Ce is smaller than CeKC, the knock feed value θR is set to 0 in step S45, the final ignition timing is calculated in step S46, and the octane number is calculated in steps S40 to S43. When it is determined that the vehicle is not in the determination zone, and after the average knock feedback delay angle amount θR is obtained in step S44, the step
S46 is executed.

In step S46, the delay angle θB of the base is changed to step S
Acceleration delay amount θACC obtained in step 18 and the above steps S36, S37, S
Final ignition timing θS
Then, in step S47, the final injection amount Ti obtained in step S24 is output to the timer to inject fuel from the fuel injection valve 28, and in the subsequent step S48, the energization time TS is calculated using the final ignition timing θS. In step S49, TS is output to the ignition timer, the ignition plug 18 is energized via the ignition coil 36 and the distributor 38, and the process returns to the start.

Now, in the control device of the engine 10 in which the control as described above is performed, when the engine 10 is accelerated, the ignition timing is set to a retard angle reflecting the octane number of the fuel used by the engine 10 in addition to the retard angle to the acceleration. The lower the value of, the larger the retard amount of the ignition timing is controlled.

Therefore, the knocking limit varies depending on the fuel used,
In particular, it is possible to prevent knocking from occurring easily during acceleration.

4 to 10 show a second embodiment of the engine control device according to the present invention.

In the embodiment shown in the figure, the fuel correction at the time of acceleration is further corrected according to the octane number of the fuel used. It is omitted, and only the characteristic points will be described below.

In this embodiment, as shown in the overall view of FIG. 4, control is performed by a control unit 34 composed of a microcomputer as in the above embodiment, but the control unit 34 includes an octane number sensor provided in a fuel tank 40. 42, a pressure sensor 44 provided in the intake passage 20, a throttle opening sensor 46 provided in the throttle valve 26,
Outputs of crank angle sensors 48 that detect the rotation of a crank shaft 10d connected to a piston 10c of the engine 10 are input, and fuel injection from the fuel injection valve 28 is controlled based on the following control flow.

FIG. 5 shows a basic routine of the control unit 34. When the control starts, the output value of the pressure sensor 44 is first input at step S100 and the manifold pressure is read at step S101.

In step S102, the basic fuel injection pulse width PINJ is calculated based on the manifold pressure and the rotation speed N calculated from the crank angle sensor 48, and in the subsequent step S103, the output value of the octane number sensor 42 is read. In step S104, the acceleration fuel correction coefficient HPRE is calculated according to the output value of the octane number sensor 42, and the process returns to the start.

Here, the acceleration fuel correction coefficient HPRE is set so that it becomes smaller as the octane number becomes larger, as shown in FIG.

On the other hand, the interrupt routine shown in FIG. 6 is executed every fixed time, for example, every 5 ms. In the interrupt routine shown in the same figure, the output value θTH of the throttle opening sensor 46 is input in step S105, the previous output value θBEF of the throttle opening sensor 46 and the change amount θ of θTH are calculated in step S106, and the step θ is calculated. In S107, the throttle opening is updated to obtain the next change.

Then, in step S108, the change θ is the acceleration determination constant θ.
It is judged whether or not it is larger than ACC. If θ is smaller than θACC, it means that the vehicle is not accelerating, so it returns to the start, but θ is θAC
If it is larger than C, it means that the vehicle is accelerating, so step S109 is executed.

In step S109, the temporary injection base pulse width PEX is calculated according to θ (acceleration request change degree), and this PEX is set to increase as θ increases, as shown in FIG.

In the next step S110, PEX is multiplied by the acceleration increase correction coefficient HPRE according to the octane number calculated in step S104 to calculate the temporary injection pulse width P'W, and in step S111 the pulse width P'W is calculated. The temporary injection is set at, and the temporary injection is performed from the fuel injection valve 28 to avoid the time delay of the fuel increase with respect to the acceleration.

Then, in the next step S112, the basic acceleration increase rate HACCB according to θ (acceleration request change degree) is obtained, and this HACCB is set to increase as θ increases, similar to PEX.

In step S113, the basic acceleration increase rate HACCB calculated in step S112 is multiplied by the acceleration increase correction coefficient HPRE according to the octane number calculated in step S104 to calculate the octane number-corrected acceleration increase correction value HACC. Return.

Further, the interrupt routine shown in FIG. 7 is executed at every constant crank angle.

In the interrupt routine shown in the figure, first, in step S114
After the interruption time is read out based on the output value of the crank angle sensor 48, the rotational speed N of the engine 10 is calculated from the difference from the previous interruption time in step S115.

In the following step S116, the injection pulse width PW is changed to step S
Step S1 to the basic fuel injection pulse width PINJ obtained in 102
Octane number-corrected acceleration increment correction value HACC obtained in 13
Is calculated by multiplying by
After a predetermined damping constant DACC is subtracted from this to set a new acceleration increase H'ACC, it is judged in step S118 whether H'ACC is larger than 1, and if H'ACC is larger than 1, In step S119, the fuel injection is set with a pulse width of PW and the process returns to the start.

On the other hand, if it is determined in step S118 that H'ACC is smaller than 1, H'ACC is set to 1 in step S120 and step S119 is executed.

FIG. 10 shows a state in which fuel is injected through the above steps.

In the apparatus of the present embodiment that controls the injected fuel of the engine 10 as described above, the fuel injection at the time of acceleration is set to the octane number by changing the temporary injection pulse width PW 'which becomes larger as the acceleration increases in accordance with the degree of acceleration. Accordingly, the higher the octane number, the smaller the acceleration increase correction coefficient HPRE, which is corrected, and the temporary injection is immediately performed. Therefore, a decrease in the air-fuel ratio immediately after acceleration is prevented.

Also, the basic acceleration increase rate HAC according to the degree of change in acceleration demand
Since CB is also corrected according to the degree of acceleration and the octane number, knocking is less likely to occur.

FIG. 11 shows the above operation more specifically,
The same figure shows the knock limit between high octave and regular in relation to the air-fuel ratio and the filling amount.

Now, the operating condition of the engine 10 is at point A in FIG. 11,
If there is a demand for acceleration, and if the acceleration amount is not increased at all, the operating point B after acceleration is reached via the curve shown by the solid line in the figure, and the knocking limit of high octave and regular is passed.

Here, if the acceleration amount is increased, the knocking limit will not be passed, but a simple acceleration amount cannot be adapted to the fuel used. Therefore, in the present embodiment, in addition to the acceleration increase, the increase value is corrected by the octane number of the fuel used, and becomes larger as the octane number becomes smaller.

As a result, the path from the pre-acceleration operating point A to the post-acceleration operating point B will differ depending on the octane number of the fuel used, and will reach A → B by avoiding the high-octane and regular knocking limits, respectively, and The optimum acceleration increase is performed for each.

The acceleration determination constant θ for the control shown in the second embodiment is
ACC is set according to the octane number, and when the octane number is low, acceleration is increased even in a small acceleration state,
If the octane number is high, the acceleration amount may not be increased unless an extremely large acceleration state is reached, and an acceleration determination level may be set.

<< Effects of the Invention >> As described in detail in the above embodiments, according to the engine control device of the present invention, the fuel amount is increased during acceleration of the engine in which the degree of change in acceleration required by the occupant is equal to or greater than the predetermined value, and The acceleration increase value of is corrected by the octane number of the fuel used, and the increase value increases as the octane number decreases, so it is possible to perform the optimal acceleration increase according to the octane number of the fuel used, and to prevent knocking. Fuel economy can be improved.

[Brief description of drawings]

1 to 3 show a first embodiment of the device of the present invention, FIG. 1 is an overall explanatory view of the device, and FIGS. 2 and 3 are control flowcharts of the device and FIG. FIGS. 11 to 14 show a second embodiment of the device of the present invention, FIG. 4 is an overall explanatory view of the device, FIGS. 5 to 7 are flowcharts for controlling the device, and FIG. Fig. 9 is an explanatory diagram showing the relationship between the octane number and its correction coefficient, Fig. 9 is an explanatory diagram showing the relationship between acceleration and temporary injection pulse width, and basic acceleration increase rate, and Fig. 10 is the throttle opening and injection pulse width during acceleration. FIG. 11 is an explanatory diagram showing the relationship between damping constants, and FIG. 11 is an explanatory diagram showing the operation of the device. 10 …… Engine, 18 …… Spark plug 26 …… Throttle valve, 28 …… Fuel injection valve 32 …… Knock sensor, 38 …… Distributor 42 …… Octane number sensor, 46 …… Throttle opening sensor 48 …… Crank angle Sensor

Claims (1)

(57) [Claims] 1. A knocking detection means for detecting knocking of an engine, a knocking suppression means for correcting an engine control amount so as to suppress knocking when knocking is detected, and a fuel component detection for detecting an octane number of fuel supplied to the engine. An acceleration request change degree detection means for detecting the acceleration request change degree, and an acceleration determination means for determining the acceleration time when the change degree is a predetermined value or more based on the acceleration request change degree detection means, The knocking detection means receives the output of the fuel component detection means and increases the fuel increase amount by the fuel increase means as the octane number decreases during acceleration. An engine control device characterized by: