JPH02238153A - Control device for engine - Google Patents

Abstract

PURPOSE:To improve accuracy in control by measuring the interval of a reference position signal from a crank position sensor so as to compute a reference time per unit crank angle, and thereby determining control timing based on an unit pulse signal per unit crank angle on the basis of said reference time and the reference position signal. CONSTITUTION:The time interval of a reference crank position signal is measured by a timer means 30 inputting output signals from a crank position sensor 14, the time interval is divided by the crank angle between reference crank positions by a reference time computing means 34 so that a reference time per crank angle of 1 deg. is thereby computed. An unit pulse signal equivalent to the crank angle of 1 deg. is generated at an unit pulse signal generating means 35 based on the reference time and clock signals from a clock generator 28. In addition, the control signal is generated at specified timing at a control generating means 36 based on the aforesaid reference crank position signal and the unit pulse signal so that an injector 8 and an ignition coil 11 are driven so as to be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an engine control device that determines the control timing of an ignition signal, a fuel injection signal, etc. by time control.

[Problems to be solved by conventional technology and inventions] Engine control units in vehicles such as automobiles use microcomputers to process signals from various sensor groups, calculate fuel injection amount, ignition timing, etc. A control signal is output to the actuator at the appropriate timing.

By the way, conventionally, in order to determine the timing of outputting a fuel injection signal, an ignition signal, etc., for example,
There are various methods as disclosed in Japanese Patent No. 608, Japanese Patent Laid-Open No. 56-9665, etc., and basically there are two methods described below.

■When the reference position signal from the crank position sensor is detected, counting of unit angle signals is started, and the control timing is set when a predetermined crank angle is reached.

That is, as shown in FIG. 5, for example, when igniting at BTDC 10 degrees,
When the reference position signal indicating 0° is detected, the dwell is started and at the same time, counting of unit angle signals for every 1° of crank angle is started, and the dwell is ended at the 81st pulse and ignition is started.

■Measures the time between the reference position signals from the crank position n sensor, and calculates the control timing as the delay time from the reference position signal.

In other words, when igniting with BTDCIO°, the 6th
As shown in the figure, BTDC1 from the crank position sensor
The time t (=T90) is measured from the interval between the reference position signal indicating 80" and the reference position signal indicating BTDC 90", and when the reference position signal indicating BTDC 90 degrees is detected,
At the same time as starting the dwell, the delay time td (=T90x(90-10)
/90), and after this delay time td has passed, the dwell is ended and ignition is started.

Both of the above two basic methods have advantages and disadvantages, and their solution has been a challenge. In other words, in ■, it is possible to detect the actual crank position with high accuracy,
While the control timing can be determined accurately, the accuracy of the control timing is affected by the configuration of the crank position sensor, which inevitably requires a highly accurate crank position sensor, which increases complexity and increases costs. invite

On the other hand, in case (2), accurate time measurement and calculation is possible using a microcomputer, etc., which simplifies the configuration of the crank position sensor and reduces costs.
In order to improve the control accuracy, the interval between the reference position signals must be narrowed, which is difficult to achieve unless the computing power of the microcomputer is increased.

[Object of the Invention] The present invention has been made in view of the above circumstances, and provides an engine control device that can improve control accuracy without causing a lack of computing power when determining control timing by time control. is intended to provide.

[Means and effects for solving the problems] An engine control device according to the present invention includes a reference time calculation means for calculating a reference time per unit crank angle from the interval of reference position signals output from a crank position sensor; unit pulse signal generating means for generating a unit pulse signal per unit crank angle based on the reference time calculated by the reference time calculating means; and control signal generating means for outputting a control signal at a predetermined timing based on the unit pulse signal.

With the above configuration, the reference time calculation means measures the interval between the reference position signals of the crank position sensor and calculates the reference time per unit crank angle. Next, based on this reference time, the unit pulse signal generating means generates a unit pulse signal per unit crank angle, and based on this unit pulse signal and the reference position signal from the crank position sensor, the engine Once the control timing is determined, a control signal is output from the control signal generating means.

[Examples of actual inventions] Embodiments of the present invention will be described below with reference to the drawings.

The drawings show an embodiment of the present invention, in which Fig. 1 is a functional block diagram of a control device, Fig. 2 is a schematic diagram of an engine control system, and Fig. 3 is a schematic diagram of an engine control system.
The figure is a circuit block diagram, and FIG. 4 is a flowchart showing a control timing setting procedure.

(Configuration of engine control system) In Fig. 2, reference numeral 1 in the figure is an engine body, and an intake pipe 4 and an exhaust pipe 5 are connected to an intake boat 2 and an exhaust boat 3 that communicate with the combustion chamber 1a of the engine body 1. An air cleaner 6 is connected to the upstream side of the suction pipe 4. Further, a throttle valve 7 is interposed in the middle of the suction pipe 4, and an injector 8 is provided directly upstream of the intake boat 2 in the suction pipe 4.

Further, an ignition plug 9 has an ignition portion exposed in the combustion chamber 1a of the engine main break 1, and the ignition plug 9 is connected to an ignition coil 11 via a distributor 10.

On the other hand, a catalytic converter 12 is interposed in the middle of the exhaust pipe 5, and a crank rotor 13 is fixedly installed on the crankshaft 1b of the engine main break 1. A sensor 14 is provided oppositely.

For example, the crank opening 13 has a crank angle of 90".
A detecting section consisting of a protrusion or a notch indicating the reference crank position is provided, and by detecting this detecting section with the crank position sensor 14, the reference crank position can be detected.

Further, the throttle valve 7 is connected with a throttle position sensor 15 and an idle switch 15a that detects the fully open position of the throttle valve 7. A quantity sensor 16 is in communication.

Furthermore, a cooling water passage 1 formed in the engine body 1
The water-drought sensor 17 faces C, and roughly the exhaust pipe 5
An 02 sensor 18 is placed directly upstream of the catalytic converter 12 .

On the other hand, reference numeral 20 is a control device, and each of the above-mentioned sensors 1 is connected to the input side.
4 to 18 and an idle switch 15a are connected thereto, and the injector 8 and ignition coil 11 are connected to the output side.

(Circuit configuration of control device) The control device 20 has a CPU 21 as shown in FIG.
, a ROM 22, a RAM 23, a timer 24 having a free-running counter and a general-purpose counter, an input interface 25, and an output interface 26 are connected to the bus line 2.
7, and a clock generator 28 is connected to the CPU 21, the timer 24, and the counter 29 to supply clock signals.

Further, the output interface 26 is connected to the static input of the converter 30, b1...
The 01...On output of the counter 29 is connected to the Bn input.

The output of the comparator 30 is connected to the reset terminal of the counter 29 and the input interface 25.
It is connected to the.

The ROM 22 stores fixed data such as control programs and control data, and the RAM 23
Stores the output values from each of the sensors 14 to 18 after data processing. Also, CPtJ 2 1
Then, according to the control program stored in the ROM 22, the fuel injection peak, ignition timing, etc. are calculated based on various data stored in the RAM 23.

On the other hand, the comparator 30 is a so-called digital comparator, and the value of the input 81...An and the value of the input 81...
The value of the Bn input is compared, and the output h state is inverted depending on the magnitude. That is, when the data from the counter 29 becomes larger than the data from the output interface 26, the output of the comparator 30 is inverted from high to low, for example. At the same time, the counter 29 is reset by the fall of the output of the comparator 30, and the counter 29 starts counting the clock signal of the clock generator 28 again from 0.

This cycle is repeated, and the comparator 3O outputs a pulse signal corresponding to the data from the output interface 26.

That is, for example, when data corresponding to a crank angle of 1 degree is output from the output interface 26, as described above, the data corresponding to a crank angle of 1 degree is output from the converter 30.
A unit pulse signal is output for every 1 degree of crank angle, and with this unit pulse signal, a signal equivalent to that of a conventional crank rotor in which a detecting section is provided for every 1 degree of crank angle can be obtained with a crank rotor 13 having a simple configuration.

Furthermore, control accuracy can be improved by narrowing the interval between the reference crank positions, and unlike conventional time control systems, there is no shortage of calculation ability for the delay time from the reference crank position.

The unit pulse signal is input to the input interface 25.
The timer 24 starts counting based on the reference position signal θref from the crank position sensor 14, and at a predetermined timing, the CPU 21
An interrupt signal is output.

As a result, previously calculated control signals such as the fuel injection signal and the ignition signal are outputted from the output interface 26 to the drive circuit 31, and the injector 8, ignition coil 11, etc. are driven.

(la noh composition) Next, the functional configuration of the control device 20 will be explained.

As shown in FIG.
0, engine rotation speed calculation means 31, intake air amount calculation means 32, various correction value calculation means 33, reference time calculation means 34
, unit pulse signal generation means 35, control signal generation means 36
, a control data block Mp, and a driving means 37.

The timer 30 determines which time interval Tθ the output signals from the crank position sensor 14, for example, the reference crank position signal θrefl indicating BTDCI 80° and the reference crank position signal θref2 indicating BTDC90'', are determined by the timer 24.
It is measured by a free running counter and output to the engine rotation speed calculation means 31 and the reference time calculation means 34.

The engine rotation speed calculation means 31 calculates the time interval T of the reference crank position signal θref measured by the time measurement means 30.
From θ, calculate engine speed and rotation number N. For example, when the reference crank position is every 90', the engine rotation speed N is N=60/(4xTθ)(rom).

The intake air amount calculating means 32 reads the output signal of the intake air suspension sensor 16 and calculates the intake air flQ.

In the various correction amount calculation means 33, the idle switch 15a
1 From the output signals of the throttle position sensor 15 and the water temperature sensor 17, various increases related to post-idle boost correction, throttle full-open boost correction, water temperature correction, and acceleration/deceleration correction are calculated, and from the output waveform of the O2 sensor 18. Calculate the air-fuel ratio feedback correction amount.

The reference time calculation means 34 calculates the time interval Tθ of the reference crank position signal θref measured by the time measurement means 30 as follows:
Divide by the crank angle between the reference crank positions to calculate the reference time T per unit crank angle, that is, 1° of crank angle.
ref is calculated and output to the unit pulse signal generating means 35.

The unit pulse signal generating means 35 generates a unit pulse signal Pt corresponding to a crank angle of 1° based on the reference time Tref calculated by the reference time calculating means 34 and the clock signal C[κ from the clock generator 28. This unit pulse signal Pt is output to the control signal generating means 36.

That is, the reference time Tref data calculated by the reference time calculation means 34 is sent to the converter 30 by ^1...A.
At the same time, the clock signal CLκ from the clock generator 28 is counted by the counter 29, and set to the 01...On output of the counter 29 and the A1...An input of the converter 30. Compare with reference time T ref data.

When the count number of the clock signal CLK, that is, the output of the force counter 29 becomes larger than the reference time 7'ref data, the output of the comparator 30 is inverted, and at the same time, the counter 29 is reset, and every reference time Tref is reset. , that is, a unit pulse signal Pt corresponding to a crank angle of 1°.

The control signal generation means 36 calculates the basic fuel injection @Tp from the engine rotation speed N calculated by the engine rotation speed generation means 31 and the intake air ffiQ calculated by the intake air stimulation generation means 32, The basic fuel injection amount To is corrected by various correction amounts calculated by the various correction value calculation means 33 to calculate the fuel injection nT, and the basic fuel injection @
Crank angles such as ignition angle and fuel injection timing are set from the control data map Ml1 using ffiTp and engine rotational speed N as parameters.

Then, a control signal is generated at a predetermined timing from the reference position signal θref from the crank position sensor 14 and the unit pulse signal P from the unit pulse signal generating means 35.

Specifically, from the crank position sensor 14, for example, BT
When the reference position signal θref2 indicating DC90' is input, the timer 24 starts counting unit pulse signals corresponding to 1 degree of crank angle from the unit pulse generating means 35, and when the preset crank angle is reached, , an interrupt signal is output from the timer 24 to the CPU 21,
The CPU 21 includes a fuel injection amount signal Ti and an ignition signal θI.
A control signal such as G is output to the driving means 37.

As a result, the injector 8 is driven by the drive stage 37, and a quantity of fuel corresponding to the intake air faQ is injected at a predetermined timing, and the air-fuel mixture is sucked into the combustion chamber 1a.
Thereafter, the energization of the ignition coil 11 is cut off at a predetermined timing, a spark is generated from the ignition plug 9, and the fuel is ignited.

(Operation) Next, the control timing setting procedure using the above configuration is explained in the fourth step.
The explanation will be given according to the flowchart shown in the figure.

In step S101, the reference position signal θref1 output from the crank position sensor 14 is taken in, and in step S1
02, the value T1 of the free running counter of the timer 24 is read.

Next, the process advances to step S103, where the next reference position signal O re output from the crank position sensor 14 is again output.
Read f2. Proceed to step 3104 and set the timer 2 above.
The value T2 of the free running counter of No. 4 is read, and the process advances to step S105.

In step S105, the value T2 of the free running counter of the timer 24 read in the step S104 is determined.
, the above-mentioned timer 24 read in the above-mentioned step S102
The reference position signals θref1 to θr of the crank position sensor 14 are obtained by subtracting the value T1 of the free running counter.
Calculate the time interval Tθ (=T2 − T1) of ef2.

Next, when the process advances to step 3106, the above step S10
The time interval Tθ calculated in step 5 is calculated using the reference position signal θre of the crank position sensor 14 that calculated this time interval Tθ.
Crank angle corresponding to f1 to θref2, for example 90
Divide by ° to find the reference time Tre per unit crank angle 1 °
After calculating f (=Tθ/90), the process proceeds to step S107.

The process advances to step S107, in which the data of the reference time Tref calculated in step 8106 is set in the comparator 30, and then the process advances to step 8108. At this time, the data output of the counter 29 that counts the clock signal from the clock generator 28 and the
The data of the reference time Tref set to 0 is compared, and when the data output of the counter 29, that is, the count number of the clock signal becomes larger than the data of the reference time Tref, the output of the comparator 30 is inverted. At the same time, the counter 29 is reset and starts counting the clock signal again from O.

This cycle is repeated, and the output of the converter 30 is changed to the crank angle 1 corresponding to the reference time Tref.
A unit pulse signal Pt of 1° is generated, and in step 8108, this 1° pulse signal Pt is counted by the timer 24, and the process advances to step S109.

In step S109, it is determined whether or not an output timing between controls that has already been calculated, such as a fuel injection multi-signal or an ignition signal, has been reached, and if the timing has not been reached, the process returns to step 8108 and returns to step 8108.゜Continue counting the pulse signal pt.

On the other hand, if it is determined in step S109 that the control timing has been reached, the process proceeds to step S110, where the fuel injection amount signal or ignition signal is output, and step S1
Return to 01.

[Effects of the Invention] As explained above, according to the present invention, there is provided a reference time numbing means for calculating a reference time per unit crank angle from the interval of group position signals output from the crank position sensor;
Based on the reference time calculated by the above cloudy time calculation means,
unit pulse signal generating means for generating a unit pulse signal per unit crank angle; and a control signal at a predetermined timing based on the reference position signal from the crank position sensor and the unit pulse signal from the unit pulse signal generating means. Since the crank position sensor is equipped with a control signal generating means for outputting a control signal, the control timing can be determined with high accuracy using only the reference position signal from the crank position sensor, and the crank position sensor can be constructed easily and inexpensively. Further, when determining control timing using only a signal at the reference position, excellent effects such as improvement in control accuracy can be achieved without causing a shortage of computing power.

[Brief explanation of drawings]

1 to 4 show one embodiment of the present invention, FIG. 1 is a functional block diagram of a control device, FIG. 2 is a schematic diagram of an engine control system, FIG. 3 is a circuit block diagram, and FIG. 1 is a flowchart showing a control timing setting procedure, and FIGS. 5 and 6 show conventional examples and are time charts of ignition timing. 20... Control device, 14... Crank position sensor, 34... Reference time calculation means, 35... Unit pulse signal generation means, 36... Control signal generation means, θre', θreri, θre f 2 = reference position signal, T ref... reference time, pt... unit pulse signal.

Claims (1)

[Scope of Claims] A reference time calculation means for calculating a reference time per unit crank angle from the interval of reference position signals output from the crank position sensor; and based on the reference time calculated by the reference time calculation means,
unit pulse signal generating means for generating a unit pulse signal per unit crank angle; based on the reference position signal from the crank position sensor and the unit pulse signal from the unit pulse signal generating means;
1. An engine control device comprising: control signal generating means for outputting a control signal at a predetermined timing.