JPH081166B2 - Engine controller - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control device that controls the fuel amount and ignition timing of an engine, and more particularly to control of the engine when adjusting the ignition timing.

[Conventional technology]

FIG. 7 shows the configuration of a conventional engine control device. In the figure, 1 is a reference angle sensor that detects a predetermined angle before the top dead center of the crank angle of an engine (not shown), for example, BTDC75 °, and outputs a reference angle signal SG, and 2 is a pressure in an intake pipe of the engine. The intake pipe pressure sensor 3 for detecting the ignition timing is an ignition timing adjustment signal device, which is composed of a switch whose one end is grounded, for example, and is turned on at the time of ignition timing adjustment to apply a ground potential signal. Reference numeral 4 denotes an idle switch which is turned on by detecting the idling position of a throttle valve provided in the intake pipe of the engine. 6 is a basic advance value calculating means for calculating a basic advance value of the ignition timing according to the engine speed and the intake pipe pressure, and 7 is a basic advance value for eliminating the difference between the actual speed and the average speed during idling operation. This is an idle stabilization correction unit that corrects an angle value. Reference numeral 8 denotes a target advance value switching means for selecting and outputting either the fixed advance value or the target advance value from the idling stabilization correction means 7 in accordance with a signal from the ignition timing adjustment signal 3. Reference numeral 9 is an advance value-time conversion means for converting the selected target advance value into time, 10
Is an ignition signal means for outputting an ignition signal IGT immediately after the lapse of the time converted as described above with reference to the reference angle signal SG. Reference numeral 11 denotes an ignition device, which includes an igniter for controlling on / off of the primary current of the ignition coil according to the applied ignition signal IGT, an ignition coil, a distributor, an ignition plug, and the like. Reference numeral 12 is a basic fuel amount calculation means for calculating a basic fuel amount from the engine speed and intake pipe pressure, and 15 is a fuel injection signal output means for converting the fuel amount into a fuel injection valve drive time, and the fuel injection valve for this time. 16 is driven in synchronization with the reference angle signal SG to open the valve. Reference numeral 17A denotes an electronic control unit, which is composed of elements 6 to 10, 12, and 15 described above, and forms an ignition signal IGT and a fuel injection signal.

Next, the operation will be described. The reference angle sensor 1 that detects the crank angle of the engine outputs a reference angle signal SG that rises at a crank angle of BTDC75 ° and falls at a crank angle of BTDC5 °. The basic fuel amount calculating means 12 is an actual rotation speed signal N _e representing the actual rotation speed of the engine obtained based on the reference angle signal SG.
And a basic fuel amount is calculated by mapping a two-dimensional map based on the pressure signal Pb representing the intake pipe internal pressure detected by the intake pipe pressure sensor 2. Fuel injection signal output means 15
Converts the basic fuel amount into a fuel injection valve drive time, outputs a fuel injection signal of this drive time width in synchronization with the rising of the reference angle signal SG, and drives the fuel injection valve 16 to open. Thus, the engine is supplied with fuel by the fuel injection valve 16.

On the other hand, the basic advance angle value calculating means 6, based on the actual revolution speed signal N _e calculated based on the reference angle signal SG and the pressure signal Pb 2
The basic advance value is calculated by mapping the dimensional map. The idle stabilization compensator 7 outputs the basic advance value as it is as the target advance value when the idle switch 4 is off and is not idle. Further, the idle stabilizing compensation means 7, if the idle switch 4 is in idle on, the average speed signal N _a calculated based on the reference angle signal SG
The basic advance value is corrected according to the difference between the signal and the actual rotation speed signal _Ne, and is output as the target advance value. As shown in FIG. 5, the characteristic of the idle stabilization correcting means 7 is that, when the actual rotation speed is smaller than the average rotation speed, the idle stabilization correction angle Δθ is set to the (+) side and the basic advance value is equal to Δθ. If the actual rotation speed is higher than the average rotation speed by correcting to the advance side and increasing the actual rotation speed,
By setting Δθ to the (−) side, the basic advance value is corrected to the retard side by Δθ to lower the actual rotational speed. The target advance value switching means 8 selects and outputs a fixed advance value as the target advance value when the ground potential signal is input from the ignition timing adjustment signal device 3,
When the ground potential signal is not input, the advance value output from the idle stabilization correction means 7 is selected and output as the target advance value. The advance value-time conversion means 9 obtains a cycle T ₁ corresponding to a crank angle of 180 ° of the reference angle signal SG, and this cycle T
Converting the theta _ADV time T _a based on ₁ and target advance angle value switching means 8 target advance value theta _ADV selected by. Ignition signal output means 10 receives the signal of the time T _a, the reference angle signal SG
When the time T _a has elapsed from the rising edge of
The ignition signal IGT is set to a level and is output to the ignition device 11. Thereby, the ignition device 11 ignites the air-fuel mixture in the combustion chamber of the engine.

The timing of the reference angle signal SG and the ignition timing signal IGT is as shown in FIG. 6 when the target advance value θ _ADV is B
If it is expressed in TDC angle, Can change θ _ADV to T _a .

[Problems to be Solved by the Invention]

Since the conventional engine control device is configured as described above, when the ignition timing adjustment signal device 3 is turned on, the advance angle value is fixed, and the idle stabilization correction is invalidated especially in the idle operation state. In addition, the suppression of fluctuations in engine speed becomes ineffective. In particular, the basic fuel amount calculated by the basic fuel amount calculating means 12 has an ideal air-fuel ratio (A / F = 1
The combustion of the air-fuel mixture is not stabilized because the amount of fuel is such that 4.7), so that the engine speed fluctuation becomes large. In the case of the ignition timing control system of the cycle prediction method as described above, it is difficult to predict the cycle when the engine speed fluctuation is large, and it is difficult to adjust the ignition timing because the actual ignition timing varies. was there.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain an engine control device capable of reducing fluctuations in engine speed during ignition timing adjustment.

[Means for solving the problem]

The engine control device of the present invention is equipped with fuel control means for controlling the amount of fuel corresponding to the operating state of the engine, supplies fuel to the engine, and ignites with a predetermined signal applied to a predetermined input terminal. In an engine control device that ignites with a fixed advance value for the ignition timing regardless of the operating condition of the engine during timing adjustment, a fuel control unit controls the fuel amount during ignition timing adjustment when a predetermined signal is applied to a predetermined input terminal. The amount of increase is corrected so as to approach the output air-fuel ratio.

[Action]

The engine control device according to the present invention inputs the ground potential signal when a predetermined signal is applied to a predetermined input terminal, that is, when adjusting the ignition timing, and corrects the fuel amount to the rich side for correction. By stabilizing the combustion of the engine by the engine, the fluctuation of the engine speed can be reduced even if the advance value of the ignition timing is fixed.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. First
FIG. 1 is a block diagram of an engine control device according to one embodiment of the present invention. In the figure, the same parts as those of the conventional device shown in FIG. 7 are designated by the same reference numerals 1 to 4, 6 to 12, 15, and 16, and the description thereof is omitted because they have the same configuration. Reference numeral 13 denotes a fuel increase correction means for increasing and correcting the basic fuel quantity calculated by the basic fuel quantity calculation means 12. Reference numeral 14 is a fuel amount switching means, which is a basic fuel amount calculating means in response to a signal from the ignition timing adjustment signal device
Basic fuel amount signal output from 12 and fuel increase correction means
One of the fuel amount signals output from 13 is selected and output to the fuel injection signal output means 15.
Reference numeral 17 denotes an electronic control unit, which is composed of elements 6 to 10 and 12 to 15 and forms an ignition signal IGT and a fuel injection signal.

Next, the operation will be described with reference to FIG. The operation already described in the section of the related art will be omitted, and only a new portion will be described. The fuel increase correction means 13 uses the basic fuel amount calculated by the basic fuel amount calculation means 12, for example, 1.
Multiply a coefficient greater than 0 to increase the fuel amount. The fuel amount corrected for this increase is such that the air-fuel ratio becomes 12.5 to 13. The air-fuel mixture having the fuel amount corresponding to the air-fuel ratio stably burns in the combustion chamber of the engine. The fuel amount switching means 14 selects and outputs the fuel amount signal from the fuel increase correction means 13 when the ground potential signal is input from the ignition timing adjustment signal device 3 during ignition timing adjustment, and the ignition amount is adjusted when the ignition timing is not adjusted. When the non-earth potential signal is input from the timing adjustment signal device 3, the basic fuel amount signal from the basic fuel amount calculation means 12 is selected and output. The fuel injection signal output means 15, which has received the selected signal, converts the fuel amount of the input signal into the fuel injection valve drive time and outputs the fuel injection signal of the time width to the fuel injection valve 16.

FIG. 2 shows a specific configuration of the electronic control unit 17 and the like in FIG. The CPU 100 performs various calculations and determinations, and performs various data processing using the memory 101 which stores the programs in the flow charts of FIGS. 3 and 4. The reference angle signal SG from the reference angle sensor 1 is input to the interrupt control circuit 102, converted into an interrupt command signal in synchronization with its rising (BTDC75 °), and transmitted to the CPU 100. Since the free-running counter 103 counts the clock pulse CP, when the interrupt command signal is generated, the count value is read by the CPU 100 via the input port 104, and the CPU 100 calculates the engine rotation cycle and the actual rotation speed. The analog detection signal of the intake pipe pressure sensor 2 is input to the A / D converter 105, converted into a digital signal, and input / output port 10
Entered in 6. The ignition timing adjustment signal device 3 and the idle switch 4 are normally turned off to input the H level, and are turned on during the ignition timing adjustment and the idle operation state to input the ground potential signal to the input port 107. The down counter 109, which is set by the CPU 100 from the output port 108 in synchronization with the fuel injection valve driving time in synchronization with the interrupt command signal, inputs the clock pulse CP and down counts until it reaches 0.
Supply base current to 0 to turn on transistor 110. When the transistor 110 is turned on, the fuel injection valve 16 is energized and is opened. The CPU 100 calculates the energization start timing data of the ignition coil of the ignition device 11 from the ignition timing data by a known method, and sets it in the down counter 112 via the output port 111. The down counter 112 has a clock pulse CP
When the count value becomes 0, the RS flip-flop 115 is set to output the H level from the Q output terminal, and the ignition coil of the ignition device 11 is energized.
Time T _a to generate an ignition signal IGT is set from the output port 113 by CPU100 in synchronization with the occurrence of an interrupt command signal to the down counter 114. Down counter 114 resets the RS flip-flop 115 when the count value over time T _a later set is 0. As a result, the Q output terminal of the RS flip-flop 115 converts from the H level to the L level, and becomes the ignition signal IGT to cut off the energization on the primary side of the ignition coil.

Next, the operation of the CPU 100 will be described with reference to FIGS. Normally, the operation of the main routine shown in FIG. 3 is performed. First, in step S1, the basic fuel amount is calculated by mapping from the already obtained actual rotation speed signal _Ne and the read pressure signal Pb. In step S2, it is determined whether the ignition timing adjustment signal device 3 is on or off. If it is off, the basic fuel amount is not increased and correction proceeds to step S4. If it is on, the basic fuel amount is larger than 1.0 in step S3. The fuel amount is calculated by multiplying a predetermined coefficient and correcting the increase, and then the process proceeds to step S4. In step S4, the fuel amount obtained in step S1 or step S3 is converted into the fuel injection valve drive time. After the process of step S4, the process returns to step S1 and the above operation is repeated.

When an interrupt command signal is generated when the reference angle signal SG output from the reference angle sensor 1 rises (BTDC75 °), the interrupt routine shown in FIG. 4 is processed. First, in step S10, the count value of the free running counter 103 is read, and the rotation cycle is calculated from the difference from the previous count value. In step S11, this rotation cycle is converted into the actual rotation speed signal N _e . In step S12, the pressure signal Pb obtained by A / D converting the output signal of the intake pipe pressure sensor 2 is read. In step S13, it is determined whether the ignition timing adjustment signal 3 is on or off. If it is on, the fixed advance value is read from the memory 101 in step S14, and if it is off, the process proceeds to step S19. In step S15, the advance angle value is converted into a down count number of the down counter 114. This count corresponds to the time T _a. At step S16, it is set to the time T _a substantial down-count down counter 114. In step S17, the energization start time data is set in the down counter 112. In step S18, the fuel injection valve drive time data is set in the down counter 109, and after this setting, the process returns to the main routine.

On the other hand, in step S19, the actual speed signal _Ne and the pressure signal P
The basic advance value is calculated by mapping with b. In step S20, it is determined whether the idle switch 4 is on or off, and if it is off, the process proceeds to step S15, and if it is on, the idle stabilization correction described with reference to FIG. move on. The processing after step S15 performs the same processing as described above.

〔The invention's effect〕

As described above, according to the present invention, when the advance value of the ignition timing is fixed for ignition timing adjustment, the fuel amount is increased and corrected, so the theoretical air-fuel ratio at idle (14.7)
The air-fuel ratio set in the vicinity is the output air-fuel ratio (12.5 to 13.
0) and the combustion of the engine is stabilized, the rotational fluctuation is reduced, the actual advance value is stabilized, and the ignition timing can be easily adjusted.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an engine control device according to an embodiment of the present invention, FIG. 2 is a configuration diagram showing a concrete configuration example of the above device, and FIG. 3 is a main diagram of the device according to the above embodiment. FIG. 4 is a flow chart showing a routine, FIG. 4 is a flow chart showing an interrupt routine of the device, FIG. 5 is a characteristic diagram of the idle stabilizing correction means, and FIG. 6 is a reference angle signal SG and an ignition signal IG.
FIG. 7 is a signal waveform diagram showing the timing of T, and FIG. 7 is a block diagram showing a configuration example of a conventional engine control device. In the figure, 1 ... reference angle sensor, 2 ... intake pipe pressure sensor,
3 ... Ignition timing adjustment signal device, 4 ... Idle switch,
6 ... Basic advance value calculation means, 7 ... Idle stabilization correction means, 8 ... Target advance value switching means, 9 ... Advance value-time conversion means, 10 ... Ignition signal output means, 11 ... ... Ignition device,
12 …… Basic fuel amount calculation means, 13 …… Fuel increase correction means,
14 ... Fuel amount switching means, 15 ... Fuel injection signal output means,
16 ... Fuel injection valve. The same reference numerals in the drawings indicate the same or corresponding parts.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area F02D 43/00 H

Claims (1)

[Claims] 1. A fuel control means for controlling a fuel amount according to an operating state of an engine is provided to supply fuel to the engine, and a predetermined signal is applied to a predetermined input terminal during ignition timing adjustment. In an engine control device that ignites with an ignition timing set to a fixed advance value irrespective of the operating state of the engine, the fuel control means controls the fuel when adjusting the ignition timing when the predetermined signal is applied to the predetermined input terminal. An engine control device characterized in that the amount of increase is corrected so as to bring it closer to the output air-fuel ratio.