JPH0447423Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to an ignition timing control device for an engine, and particularly to an ignition timing control device for an engine equipped with an automatic transmission.

(Prior Art) In order to improve the thermal efficiency and fuel efficiency of an engine, so-called MBT control, which controls the ignition timing to an advance value that allows maximum torque to be obtained, is well known. In such a device, the output torque of the engine is detected, and the ignition timing is controlled based on the detected torque so that the output torque is maximized. For this reason, a cylinder pressure sensor that detects the cylinder internal pressure is used to detect the output torque (for example, as disclosed in Japanese Patent Application No. 56-57010), or a torque sensor is attached to the power transmission shaft.

(Problem to be solved by the invention) By the way, when detecting the output torque using the cylinder internal pressure sensor, it is necessary in principle to integrate the cylinder internal pressure by weighting it with the crank angle.
Converting pressure to engine torque is not easy. In other words, the inertial force of the piston produces a rotational force on the crankshaft, but there is an inclination φ between this rotational force and the force transmitted to the connecting rod, and there is also an inclination φ between the axial direction of the connecting rod and the direction in which the crank engages. Since there is also a slope α between them, the rotational force of the piston eventually includes these slopes φ and α as factors (weights), making integration difficult.

Furthermore, when detecting the torque acting on the power transmission shaft, it is necessary to detect torsion of the transmission shaft given as an analog value, which poses a problem in that the torque signal transmission device is costly.

SUMMARY OF THE INVENTION An object of the present invention is to provide an ignition timing device in which torque calculation from a detection signal is easy and transmission of the detection signal is inexpensive.

(Means for Solving the Problems) FIG. 1 is an overall configuration diagram for clearly showing the configuration of the present invention. Reference numeral 1 denotes an input shaft rotation speed detection means that detects the rotation speed of the input shaft of the torque converter. Reference numeral 2 denotes an output shaft rotation speed detection means that detects the rotation speed of the output shaft of the torque converter. The torque converter connects an input shaft and an output shaft via a fluid coupling, and constitutes a part of an automatic transmission.

3 is a torque calculation means, and these detection means 1,
Based on the two rotational speeds detected in step 2, an input torque coefficient corresponding to the rotational speed ratio is stored, and the ignition timing is advanced by a predetermined value based on this input torque coefficient and the rotational speed ratio. Calculate the output torque of the engine. Reference numeral 4 denotes an ignition timing control means, which further corrects the advance angle when the torque increases and retards the angle when the torque decreases according to the calculated torque before and after the advance angle when the ignition timing is advanced. In addition, when the ignition timing is retarded, the ignition timing is controlled so that when the torque increases, the ignition timing is further retarded, and when the torque decreases, the ignition timing is advanced according to the calculated torque before and after the retard. do.

(Function) In this invention, an input torque coefficient corresponding to the ratio of the output shaft rotation speed and input shaft rotation speed of the fluid coupling is stored, and the output torque of the engine is calculated based on this input torque coefficient and the ratio of the two rotation speeds. Since it is calculated,
Torque calculation can be easily performed. For example, if the relationship between the input torque coefficient and two rotational speed ratios is stored in a table, the main processing will be searching this table, and there will be no need to perform weighting and integration using crank angle.

When the torque calculated in this way increases before and after the advance, the ignition timing is further advanced, and when the torque decreases, the ignition timing is retarded.
Maximum torque can be obtained regardless of operating conditions.

Similarly, when the torque increases before and after retardation, the ignition timing is further retarded, and when the torque decreases, the ignition timing is advanced and corrected to obtain the maximum torque.

Further, if the input shaft rotation speed and the output shaft rotation speed are detected using existing sensors, there is no need to newly provide means for detecting these rotation speeds, and the cost does not increase.

(Example) Figure 2 is a schematic configuration diagram of an example of this invention.
This shows what is applied to a 4-stroke, 6-cylinder engine. In the figure, the engine body (not shown) is provided with a crank angle sensor 11, an intake air amount sensor 12, and a throttle valve fully closed detection switch 13, which are similar to the conventional ones.

Here, the crank angle sensor 11 indicates a crank angle of 120°.
Generates reference position pulse PCL ₁ every time (every explosion stroke) (for example, generates at 70° before compression top dead center of each cylinder)
It consists of a reference angle sensor 11A that generates an angle pulse PCL 2 every 2 degrees of crank angle, and a relative angle sensor 11B that generates an angle pulse PCL ₂ every 2 degrees of crank angle, and detects the reference position of the crank angle and the engine rotation speed.

Reference numerals 15A and 15B denote an input shaft rotation speed sensor and an output shaft rotation speed sensor, which respectively generate pulses proportional to the rotation speeds of an input shaft and an output shaft of a torque converter of an automatic transmission (not shown). The specific configuration may be the same as that of the reference angle sensor 11A and the relative angle sensor 11B.

These sensors 11A, 11B, 12, 15
A, 15B, and the detection signals from the switch 13 are input to the interface 17 of the control circuit 16.
The control circuit 16 is composed of an interface 17, a central processing unit (CPU) 18 for performing control operations, a memory (ROM) 19, a memory (RAM) 20, and a reference clock 21 for generating clock pulses for synchronizing control operations. Ru.

The CPU 18 mainly includes a free running counter (FRC) 25 that increments (increases) its value at regular intervals, and two input capture registers (ICR ₁ ,
ICR ₂ ) consists of 26 and 27. That is,
The FRC 25 receives a clock pulse and increases its value at regular intervals. ICR ₁ 26, ICR ₂ 27 are
When a pulse is input from the input shaft rotation speed sensor 15A and the output shaft rotation speed sensor 15B, it is activated by the edge of this pulse, and the value T ₁ of FRC25 at that time,
At the same time as storing T ₂ respectively, interrupt signals Iic ₁ and Iic ₂ to the main control performed by the CPU 18 are generated.

The interface 17 is connected to the reference angle sensor 15A.
Pulse PCL1 generated by the relative angle sensor 15B,
The first is a rotation speed detection function 28, which detects the engine rotation speed Ne by counting the angle pulse PCL2 for a predetermined time. The second is an interrupt signal generation function 29, which is generated by the CPU 18 at every predetermined crank angle in synchronization with the engine rotation.
In other words, the constant crank angle interrupt signals _IA1 and _IA2 are a signal _IA1 which interrupts _the crank angle _A1 for setting the ignition timing, _and
and a signal _IA2 which interrupts the crank angle _A2 which calculates the engine output torque from the input and output revolutions of the torque converter. The third is an ignition signal generating function which counts the angle pulse PCL2 and generates an ignition signal to the ignition circuit when it reaches the crank angle (ignition advance value Θ before top dead center of the compression stroke) set in an ignition timing register (RA) 30. Reference numeral 31 denotes an A/D converter which converts the intake air amount Qa detected as an analog value from the intake air amount sensor 12 into a digital value.

The ignition circuit is composed of a power transistor 32 that cuts off the ignition coil primary current in response to an ignition signal, an ignition coil 33, a distributor 3 output, and a spark plug 35.
Ignition timing is controlled by a control circuit 16.

Next, before explaining the contents of the operations carried out by the CPU 18, a method for determining the output torque of the engine from the input/output rotational speed of the torque converter will be explained based on FIG. The figure is a characteristic diagram of the torque converter, and the horizontal axis is the input shaft rotation speed of the torque converter.
Rotation speed ratio e between Np and output shaft rotation speed Nt (=Nt/Np),
The vertical axis is the input torque coefficient τ (input shaft torque Trq and Np
τ=Trq/Np ² ).

Therefore, the input shaft torque Trq (as the input shaft of the torque converter and the output shaft of the engine are directly connected, it is also the output torque of the engine) is determined by the following procedure. That is, if Np and Nt are known, e can be found by division. From this e, τ can be found using the characteristic diagram shown in the same figure. τ obtained in this way
Trq (=τ・Np ² ) can be found from Np, which is already known.

Note that the rotation speed N has a reciprocal relationship with the period T (=1/N), so instead of Np and Nt, find the input shaft period Tp and output shaft period Tt of the torque converter,
Trq can be similarly determined from Tp and Tt.
In this case, in the same figure, e=Tp/Tt, τ=
Trq can be found from Trq・Tp _U2 .

3 and 4 are flowcharts showing the contents of the operations performed by the CPU 18. Figure 3 is 15A, 1
The periods Tp (ΔT ₁ ) and Tt (ΔT ₂ ) of the input and output shafts of the torque converter are determined from _the pulses generated _at 5B.
Find Trq and set the ignition timing based on this Trq.
It is controlled by MBT. Here, the numbers indicate each step.

Note that the basic ignition advance value _ΘB (the ignition advance value is determined by the crankshaft before top dead center The data of ) which is a numerical value representing the angle is
The current Θ _B is read out from Qa and N, which are stored in the ROM 19 and detected according to the operating state, by table lookup.

Referring to FIG. 3, operations are performed each time an input capture interrupt signal is generated. When input capture interrupt signals Iic ₁ and Iic ₂ occur, 40
Check from Iic ₁ or Iic ₂ at , and if Iic ₁ is determined, ΔT ₁ corresponding to the period of the input shaft is determined at 41 and 42, and if Iic ₂ is determined, 4
In steps 4 and 45, ΔT ₂ corresponding to the period of the output shaft is determined.

That is, in step 41, the count value of ICR ₁ 26 is read into the accumulator A, and in step 42, the difference ΔT ₁ from the previously read count value T ₁ is determined. This ΔT ₁ corresponds to the time between pulses input from the input shaft rotation speed sensor 15A, and as the rotation of the input shaft becomes faster, ΔT ₁ becomes shorter, and as the rotation becomes slower, ΔT ₁ becomes longer. The period of the input shaft is detected.

The operation is the same when the interrupt signal Iic ₂ is determined.
The difference ΔT ₂ between the count value of ICR ₂ 27 and the previously read count value T ₂ is determined. This ΔT ₂ corresponds to the period of the output shaft. (44, 45) In addition, in 43 and 46, the current accumulator A
The read value is stored in memory for the next calculation at T ₁ ,
Store as T ₂ .

In FIG. 4, the operation is performed in synchronization with engine rotation. Constant crank angle interrupt signal IA ₁ ,
When IA ₂ occurs, check whether it is IA ₁ or IA ₂ at 50, and if it is IA ₁ , correct the basic ignition advance value Θ _B at 51 and 52, and if IA ₂ , check at 53 to 57. The advance angle value correction amount ΔΘ of Θ _B is determined so that the actual engine output torque Trq is maximized.

In other words, if IA ₂ is determined at 50, then 5
In step 3, the torque converter input torque (engine output torque) Trq is obtained from the table stored in the memory in advance for ΔT ₁ and ΔT ₂ by table lookup, and this Trq is applied to the accumulator A.
Load into.

In this case, since the torque signal for calculating the output torque is generated by a pulse that detects the input/output shaft rotation speed (or period), it can be detected as a digital signal. Therefore, the torque signal transmission device may be simple.

Also, since the table is designed to calculate Trq (=f(ΔT ₁ , ΔT ₂ )) using only ΔT ₁ and ΔT ₂ as variables, there is no need to perform complicated calculations such as weighting by crank angle. Therefore, calculation of Trq is easily performed.

At step 54, the difference ΔTrq (=A-Trq) between the value of this accumulator A and the previously determined input torque Trq is calculated, and at 55 it is checked whether ΔTrq is positive or negative.

If ΔTrq>0, the previous lead angle value correction amount ΔΘ is set to the lead angle value correction amount α per time.
(If ΔTrq>0, the sign of α is the same as the previous sign.) The value ΔΘ+α (for example, α>0) is set as the current advance angle value correction amount ΔΘ. 55 and ΔTrq<
If it is 0, the value obtained by inverting the sign of α in 57 and adding it to the previous lead angle value correction amount ΔΘ (ΔΘ + α (if α>0 last time, then α<0 this time) is used as the current lead angle. Let the value correction amount be ΔΘ.

At step 51, this ΔΘ is added to Θ _B to obtain the final ignition advance value Θ. At step 52, the obtained Θ is set in RA30 of the interface 17.

That is, if the correction amount α is, for example, positive, the ignition timing is advanced by this correction, and as a result, if ΔTrq>0, it indicates that the output torque is increasing. In order to further increase the torque from this state, it is sufficient to continue advancing the angle. Therefore,
In this case, a correction having the same sign as the previous correction amount α is performed.

Similarly, if ΔTrq<0 when α is positive, the output torque has decreased due to the advance angle, so in order to increase the output torque, the angle must be retarded. Therefore, in this case, correction with the opposite sign is performed by changing the sign of α.

FIG. 5 is a timing chart showing the effects of this invention. Pulse PCL ₁ output from the reference angle sensor 11A from the top, angle synchronization interrupt signal
The engine output torque Trq calculated from the generation timing of IA ₁ and IA ₂ , ΔT ₁ and ΔT ₂ , torque change amount ΔTrq, one-time advance angle value correction amount α, and ignition advance value Θ are shown. Note that the horizontal axis is time.

Now, divide the time into t ₀ , t ₁ , t ₂ , t ₃ ..., and t _i
It is assumed that IA ₁ occurs at (i is an even number) and IA ₂ occurs at t _i-1 . Also, Θ at time t ₀ is Θ ₀ (=Θ _B +
ΔΘ ₁ ), IA ₂ occurs at time t ₁ and the output torque is
It is assumed that it is calculated as Trq ₁ .

At time _t2 , _Θ2 (= _ΘB + _ΔΘ3 ) is set by adding _ΔΘ3 (= _ΔΘ1 +α) _to ΘB. Note that α＞
Suppose it is at 0. As a result, the torque change amount ΔTrq found at time t ₃ is ΔTrq (=Trq ₃ −Trq ₁ )>0, so the output torque Trq ₃ is larger than Trq ₁ , and the advance angle correction is correct.

Therefore, in order to continue the advance angle correction without changing _the sign of α, the correction amount ΔΘ ₅ =ΔΘ ₃ + α(ΔΘ ₅
>ΔΘ ₃ ), and Θ ₄ =Θ _B +ΔΘ ₅ is set.

Thereafter, in the same way, at time t _i (i is an even number), the corrected advance angle value Θ _i =Θ _B +ΔΘ _i+1 is set, and the time
At t _i+1 (i is an even number), output torque Trq _i+1 is calculated, and if ΔTrq (= Trq _i+1 − Trq _i-1 ) > 0, the correction value ΔΘ _i+1 = ΔΘ _i-1 +α (α>0) is obtained. however,
In the figure, i is up to 5 as Trq increases.

Next, let us describe the case where the output torque decreases.
As a result of setting the lead angle value Θ ₆ (=Θ _B + ΔΘ ₇ ) at time t ₆ , the output torque Trq ₇ at time t ₇ is smaller than Trq ₅ , which means that the lead angle correction has been made too much. must perform retardation correction.

Therefore, at time t ₈ , the sign of α is inverted (α
<0), the correction amount ΔΘ ₉ =ΔΘ ₇ +α (ΔΘ ₉ <ΔΘ ₇ ) is calculated, and Θ ₈ (=Θ _B +ΔΘ ₉ ) is set. As a result, a retardation correction is performed, and at time _t9 , output torque Trq ₉ is again larger than Trq ₇ .

In this way, the advance angle value Θ _B is increased or decreased so that the output torque Trq is maximized, and it is possible to control Θ close to the optimal value Θ _MBT (the minimum advance angle value that yields the maximum torque). It will become.

In this example, we explained a method that separately detects the engine rotation speed and the input/output rotation speed of the torque converter, but in automatic transmissions, the engine output shaft and the torque converter input shaft are directly connected, so the engine speed If the number detection means also serves as the rotation speed detection means for the input shaft of the torque converter, and the rotation speed of the output shaft of the torque converter is also determined from the vehicle speed sensor and the gear position at that time, it will be possible to add new information to the input shaft. It is no longer necessary to provide each rotation speed detection means of the output shaft, and there is no increase in cost when calculating the engine output torque.

(Effect of the invention) This invention provides input shaft rotational speed detection that detects the rotational speed of the input shaft in an engine equipped with an automatic transmission having a torque converter that connects an input shaft and an output shaft via a fluid coupling. means, an output shaft rotation speed detection means for detecting the rotation speed of the output shaft, an input torque coefficient corresponding to the rotation speed ratio based on the two detected rotation speeds, and an output shaft rotation speed detection means for detecting the rotation speed of the output shaft; a torque calculating means for calculating the output torque of the engine before and after the ignition timing is advanced or retarded by a predetermined value based on the numerical ratio; and the torque before and after the calculated advance when the ignition timing is advanced. When the torque increases in accordance with the ignition timing, the advance angle is further corrected, and when the torque decreases, the ignition timing is further corrected, and when the ignition timing is retarded, the torque is increased according to the calculated torque before and after the ignition timing. Then, since we have provided an ignition timing control means that controls the ignition timing to further correct the delay and to correct the advance when the torque decreases, it is possible to obtain the maximum torque while weighting the torque calculation by the crank angle. This can be done easily and accurately without the need for integration, and does not increase costs.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram for clearly showing the configuration of this invention. FIG. 2 is a circuit diagram of an embodiment of this invention. FIGS. 3 and 4 are flowcharts showing the control contents. FIG. 5 is a timing chart illustrating the effects of this embodiment. FIG. 6 is a characteristic diagram showing the input shaft torque coefficient of the torque converter. DESCRIPTION OF SYMBOLS 1...Input shaft rotation speed detection means, 2...Output shaft rotation speed detection means, 3...Torque calculation means, 4...Ignition timing control means, 11A...Reference angle sensor, 11
B... Relative angle sensor, 12... Intake air amount sensor, 13... Throttle valve fully closed switch, 15A... Input shaft rotation speed sensor, 15B... Output shaft rotation speed sensor, 16... Control circuit, 17... ...Interface, 18...CPU, 19...ROM, 20...
RAM, 21... Reference clock, 25... Free running counter, 26, 27... Input capture register, 28... Rotation speed detection function, 29...
...Interrupt signal generation function, 30...Ignition timing register, 32...Power transistor, 35...Ignition plug.

Claims (1)

[Scope of utility model registration request] In an engine equipped with an automatic transmission having a torque converter that connects an input shaft and an output shaft via a fluid coupling, the engine includes an input shaft rotation speed detection means for detecting the rotation speed of the input shaft, and an input shaft rotation speed detection means for detecting the rotation speed of the output shaft. An output shaft rotational speed detection means to be detected and an input torque coefficient corresponding to the rotational speed ratio based on the two detected rotational speeds are stored, and the ignition timing is determined based on the input torque coefficient and the rotational speed ratio. A torque calculation means calculates the output torque of the engine before and after the engine is advanced or retarded by a value, and when the ignition timing is advanced and the torque is increased according to the calculated torque before or after the advance, the torque is further advanced. When the torque decreases, the ignition timing is retarded, and when the ignition timing is retarded, when the torque increases, the ignition timing is further retarded, and when the torque increases, the ignition timing is further retarded. 1. An ignition timing control device for an engine, comprising ignition timing control means for controlling the ignition timing so as to advance the ignition timing when the ignition timing decreases.