JPS5951141A - Electronic fuel injection timing control method of internal-combustion engine - Google Patents

Abstract

PURPOSE:To reduce the number of cylinders whose ignition plugs are subjected to direct attack of fuel even if synchronized injection in all cylinders is performed by advancing the injection timing from the ignition timing in an operating range which involves the problem of incomplete firing of the ignition plugs. CONSTITUTION:At a step 110, it is discriminated whether the engine condition is in the operating range which involves the problem of incomplete firing of ignition plugs or not. If YES, at a step 112 it is discriminated whether the varied quantity of sucked air per one revolution of the engine, DELTAQ/N is over a specified value or not. If YES at both the steps 110 and 112, the engine condition shows that it stands in the range which involves the problem of incomplete firing of the ignition plugs. At the next step 113, fuel is injected at a timing which advances from an ignition timing thetaig by (gamma) of a crank angle. The number of the cylinders whose ignition plugs are subjected to direct attack of fuel can be thus reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion (electronically controlled weir) detection method, particularly for an automobile equipped with an electronically controlled injector of a simultaneous injection method in all cylinders during the ignition 16 period. An electronically controlled wholesale fuel system for internal combustion engines that injects a determined amount of fuel into all cylinders at the same time in synchronization with the ignition timing, depending on the engine operating conditions. This invention relates to improvements in the injection Q1 method.

One of the yj methods for supplying a mixture with a predetermined air-fuel ratio to the combustion chamber of an internal combustion engine such as an automobile engine is an electronically controlled fuel mixture.
IIN (Some JJ devices are used. In this system, injectors for injecting fuel into the engine are installed in several engine cylinders, for example, in the intake manifold of the engine, and the valve opening of the injector is connected to the engine. By controlling the engine according to the operating condition, a mixture having a predetermined air-fuel ratio is supplied to the engine combustion chamber.

The most common control method for this electronically controlled fuel injection system is so-called ignition-synchronized all-cylinder simultaneous injection, in which the ignition timing is synchronized and all the injectors of each cylinder are opened at the same time. This method is often used, but especially when the throttle valve is fully opened after a cold start, it is often repeated. When the t!i I+ injection is performed at the time of interruption, the injected fuel directly hits the spark plug, which has the disadvantage that the spark plug is likely to become clogged.

The present invention has been made in order to eliminate the above-mentioned conventional drawbacks.The present invention provides an electronically controlled fuel injection method for an internal combustion engine that can prevent the spark plug from becoming stiff due to direct impact of the injected fuel on the spark plug. The purpose is to provide.

The present invention provides an electronically controlled fuel injection method for an internal combustion engine in which an amount of fuel determined according to the engine operating condition is injected simultaneously into all cylinders in synchronization with the ignition timing. In the problematic operating range, the fuel injection timing is advanced and the fuel is injected before the ignition timing to reduce the number of cylinders in which the injected fuel directly hits large spot plaques. , the above objective has been achieved.

Further, the operating range in which smoldering of the spark plug becomes a problem is during acceleration during engine warm-up.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an intake air amount sensing type electronically controlled fuel injection device for a single engine automobile, in which the electronically controlled fuel injection method for an internal combustion engine according to the present invention is adopted, will be described in detail with reference to the drawings.

As shown in FIG. 1, this embodiment includes an air flow sensor 12 for detecting the flow rate of intake air taken in by an air cleaner (not shown), a throttle body 14, and a sensor installed in the driver's seat. A throttle valve 16 for controlling the flow rate of intake air, which is opened and closed in conjunction with an accelerator pedal (not shown), and a throttle valve 16 that is turned on when the throttle valve is fully open, for detecting the fully open state of the throttle valve 16. The idle switch 18 and the surge tank 20 for preventing intake interference are installed in the intake manifold 22 corresponding to each cylinder of the engine 10 to pressurize the air cylinders 1 to 1 of each stage of the engine 10. The combustion chamber 10a of each cylinder of the engine 10 is connected to an injector 24 for intermittently injecting fuel and an intake valve 26.
Ignition plaque 28 for igniting the air-fuel mixture introduced into the
and for detecting the lean-rich state of the exhaust air-fuel ratio relative to the target air-fuel ratio (for example, the stoichiometric air-fuel ratio) from the degree of acid accumulation in the exhaust gas discharged through the exhaust valve 30. An oxygen concentration sensor (referred to as 02 sensor) 34 disposed on the downstream side of the exhaust manifold 32, and an oxygen concentration sensor (referred to as 02 sensor) disposed in the middle of the exhaust pipe 36, which detects HC and GO, which are harmful components in the exhaust gas, are disposed in the middle of the exhaust pipe 36.
,' A three-way catalytic converter 38 for simultaneously purifying NOx, and an engine for distributing a high-pressure ignition secondary signal given from the ignition coil/10 to the spark plugs 28 of each cylinder of the engine 10. 10, which rotates in conjunction with the rotation of the crankshaft 42a, and a distributor/I2 that rotates in conjunction with the rotation of the crankshaft 42a, and the rotation of the distributor shaft 42a built in the distributor 42.
21. a; U 'l', crankshaft is, for example, 30°
, a crank angle control /I4, /I6 that outputs a rotation angle signal every time it rotates 360'°, and a first engine cooling rim IJ water wetter installed at the cylinder tab 1()b of the first engine 10. The engine speed is determined from the rotation angle signal of the output of the crank angle angle 44; The basic injection time per process is used as a sieve, and this is corrected according to the engine cooling water temperature of the water temperature sensor 48, etc., and furthermore, when the air-fuel ratio feedback condition is satisfied, it is detected from the 02 sensor 34 output. The effective injection time is determined by correcting the basic injection time according to the state of the air-fuel ratio, and for example, all injectors 24 are synchronized with the ignition timing of the No. 4 cylinder.
An engine control device 52 that outputs a valve opening time signal all at once.
In the intake air amount sensing type electronically controlled fuel injection system of an ignition synchronized all cylinder simultaneous injection method for a four-cylinder automobile engine 10, which is equipped with Set the fuel injection timing to the specified crank angle γ.
(For example, γ = 5 to 10° CA), and output the valve opening time signal to all injectors 24 at the same time before the ignition timing, and IIJ! tIi) The number of cylinders in which the fuel directly hits the spark plug 28 is reduced to only one cylinder.The engine control side 1) 2 is shown in Fig. 2; For example, microphone 1] group l-1t! is used to perform various arithmetic operations. A central processing unit (MP (J) 60 consisting of a tree, the air flow controller 12 output, the 0
An analog-to-digital converter (A/D) with 4 analog multiplex functions to sequentially convert and input the Noah program signals such as the 2 txn 34 output and the water itxn → Noah 18 output into digital signals. a converter (referred to as 4) 64, an input/output port (referred to as I710 port 1) 66 for receiving the outputs of the crank angle converters 44, 46, the output of the idle switch 18, etc.; M l) U
A random access memory (referred to as RAM) 68 for temporarily storing calculation data etc. in 60;
A read-only memory (referred to as ROM) 70 for storing control programs and various data, etc., and the M P
The input/output capo 1 to 1 outputs the listening time signal to the injector 24 according to the calculation result of U60 and J3.
(referred to as I10 boat) 72 and each of the above-mentioned component devices to transfer data and instructions, etc.
Senbus 74 (consisting of.

A well-known speed signal forming circuit is provided in the I10 boat 66, and forms a digital signal representing the rotational speed of the engine 10 from the pulse signal for every crank angle 30' of the crank angle sensor 1) 44 output. It is made to be.

The pulse signal for every 360 degrees of crank angle output from the crank angle hinger 46 works together with the pulse signal for every 30' crank angle to generate an interrupt request signal for fuel injection pulse width calculation, a fuel injection start signal, and , used to form cylinder-specific signals, etc.

The +:<o M70 contains a main processing routine program, a main processing routine program for fuel injection pulse width control, an interrupt processing routine program for calculating various correction coefficients, J3, and others. program,
Furthermore, various data necessary for these calculation processes are stored in advance.

The port 72 includes a well-known fuel cell including a presettable town counter and a register.
A jet 0/j control circuit is provided, and ~I l]U 6
An injection pulse signal having the pulse width is generated from a digital signal relating to the fuel injection pulse width sent from zero. This injection pulse signal is sent to all the injectors 24 simultaneously via a drive circuit (not shown), for example, in synchronization with the ignition timing of the No. 4 cylinder, or at a timing a predetermined crank angle γ apart from the ignition timing. , prune these. As a result, the amount of fuel 1 corresponding to the pulse width of the injection pulse signal is injected.

Note that, as this engine control device 52, devices having various configurations different from the above configuration can be used. For example, without providing a speed signal forming circuit in I10 boards 1 to 66, the MPU 60 directly receives a pulse signal for a predetermined crank angle, and the MPU 60 is configured as if it were a V node. Also, I1
1:1 salt spray inside boat 72 [1:1 control circuit installed]
It is also possible to use the software i) to create a signal that has a logical value of ii 11+ for a period of time corresponding to the injection pulse width.

The action will be explained below.

During its main processing routine, the MPU 60 takes in the latest data representing the engine rotational speed N from the I10 port 66 and stores it in the RAM 68. Also, A/D
By the A/D conversion completion interrupt from the converter 64, the latest data indicating the intake air flow rate Q of the engine, the latest data having a value corresponding to the output voltage of 02 Century-32, and the engine cooling water temperature are displayed. The latest data representing the HW is taken in and stored in the RAM 68.

M1] U60 then executes a processing routine as shown in FIG. 3 in response to an interrupt request signal generated at a predetermined crank angle position, and limits the fuel injection pulse width τ.

This type of processing routine is well known, but its contents are
1 will be briefly explained. Mt) U3O first inputs the data of intake air flow IQ and engine speed +QN from RAM 68 in step 101, and in step 102 calculates the basic injection pulse width τ0 using the following formula. .

Z-04-1<・Q,・N
・・・ ・・・ ・・・ (1) Gogo (K is a constant (゛).

Then, the process proceeds to step 103, where the correction coefficient Co i of the pond is determined according to the basic injection pulse width τ0, the noise back correction coefficient Cfb, the cold J111 water temperature 111W, etc.
43, the final actual i) injection q is calculated by the following formula using the voltage τV corresponding to the ineffective injection q1 hour of the O injector 2/I.
Calculate one pulse width τ.

τ←τo−cfb・Go×τV... (2> One (, Proceed to step 104 and calculate the calculated execution Di Q=
Data corresponding to one pulse width τ is loaded into the register of I10 port 72, and this routine is executed by Hiiragi, I7! l
I.

Father, the determination of fuel injection timing according to the present invention is shown in Fig. 4 at 7j.
It is carried out according to a processing routine similar to pickpocketing.

First, in step 109, the water temperature is 1t.
? A factor (hereinafter referred to as an engine condition factor) indicating the engine condition such as the engine cooling water temperature T HW of the engine output of 4B is manually input, and in step 110, it is determined that the engine condition factor indicates that the smoldering of the spark plug 28 is a problem. It is determined whether or not the engine BJi II is in the operating range, for example, whether the engine cold rim 11 is in the engine BJi II at a temperature lower than a predetermined temperature α. If the determination result is positive, step 11
Step 1, enter a factor representing the acceleration state (hereinafter referred to as F1 acceleration state factor) such as 〇/N to the amount of change in intake air amount per engine revolution, and step 112, the acceleration state factor is the spark plug. 28 is in a problematic operating range, for example, it is determined whether the change mΔQ/N between engine and intake air per rotation exceeds a predetermined value β. If the determination result is positive, that is, if both the engine condition factor and the acceleration condition factor indicate that there is an operating range ζ in which smoldering of the spark plug 28 is a problem, the process proceeds to step 113, and the engine operation is performed. The fuel injection timing θ[1 is determined by subtracting the predetermined crank angle γ from the ignition timing θig determined according to the state, and this routine ends. On the other hand, step 110 or 11
When the judgment result in 2 () is negative, that is, either the engine condition factor or the acceleration condition factor is
When the ignition plaque 2B glue drift is out of the problematic operating range, the process proceeds to step 114, where the ignition timing θig determined according to the engine operating condition is changed to 1111θ[i when the fuel r1 is injected, Exit this routine.

The process of each cylinder of the engine 10 in J5 in this embodiment,
Ignition timing θi (l
Figure 5 shows an example of the relationship between J3 and 18I Q'J time θfi. As is clear from the figure, in the state shown in Fig. 5, the 1st and 2nd cylinders are in the intake stroke at the breakpoint of ignition timing θig, and in synchronization with this ignition timing θig, the When all cylinders are checked for fuel at the same time,
@The fuel injection yf31 directly hit the spark plugs 28 of the 1st and 2nd cylinders, and there was a problem with the spark plugs shaking. According to θ[i, the cylinder in which the fuel 81 directly hits the spark plug 28 has a gap between two aromas, 1
The incense cylinder is ignited by a single blow of injected fuel and the lug 28 is ignited.

In the above-mentioned example before J3, the engine condition factor for determining the operating range where spark plaque smog is a problem is the engine cooling water temperature 1'1-1W, and the acceleration condition factor is the engine intake per rotation. However, the types of engine condition factors and acceleration condition factors are not limited to these, and for example, the change in engine rotational speed Ii △N can be expressed as an acceleration condition factor. It is also possible to use the amount of change Δτ in the pulse width.

Furthermore, in the above embodiments, the present invention was applied to a four-cylinder automobile engine equipped with an electronically controlled fuel injection device that senses the amount of intake air; however, the scope of application of the present invention is not limited thereto; Automotive multi-cylinder engines equipped with other types of electronically controlled fuel injection devices, such as pipe pressure sensing type, or
It is clear that the present invention can be similarly applied to general multi-cylinder engine engines. An example of the relationship between the process of applying d'3 to each cylinder and the ignition timing θig and fuel injection timing θfi at d3 during acceleration during warm-up of the engine when the present invention is applied to a six-cylinder automobile engine is shown below. Shown in Figure 6. It is clear from the figure that when fuel is injected in synchronization with the ignition timing θig of the 6tLt cylinder as in the past, the fuel for the 3-cylinder C injection of the 1f# cylinder, the 2nd cylinder, and the 4th cylinder is the spark plug. However, according to the present invention, when the fuel is injected at the predetermined crank angle γ and lJ earlier than the ignition 1 stage θig, the fuel is injected at the timing θ[i]. This prevents the injected fuel from directly hitting the spark plaque in the number cylinder.

As explained above, according to the present invention, in the operating range where spark plug burr is a problem, it is possible to reduce the number of cylinders in which the injection twist 1 directly hits the spark plug, and therefore the C1 ignition From the plug's clenching, Kita's life is slow and sluggish.
The excellent effect of iiJ function is achieved by preventing driving performance problems such as shortness of breath, back no eye pull 7, and start failure.

[Brief explanation of the drawing]

FIG. 1 shows an electronic control ( ) 11 combustion 1 of an internal combustion engine according to the present invention.
A 4-cylinder automobile engine with ignition synchronization and simultaneous injection in all cylinders with intake air flow sensing and electronically controlled fuel injection! ) A sectional view including a partial block diagram of the configuration of the embodiment of the J device, FIG. 2 is a block diagram showing the configuration of the engine control device used in the above embodiment, and FIG. Similarly, FIG. 4 is a flowchart showing the main part of the crank angle interrupt processing routine for determining the fuel injection pulse width, FIG. 4 is a flowchart showing the processing routine for determining the fuel injection timing, and FIG. , a diagram showing an example of the relationship between the process of each cylinder, ignition timing, and fuel injection timing in the above embodiment; FIG. FIG. 2 is a diagram showing an example of the relationship between the process of each cylinder, ignition timing, and fuel injection timing when applied to the present invention. 10...Engine, 12...Air flow sensor 1
ノ, 24...Injector, 42...Distributor, 44.46...Crank angle sensor 4ノ, 48...
・Water temperature, 52...Engine control IO device. Agent Takaya Ron (one idiot) Figure 3 4FA

Claims (1)

[Claims] ('I) The amount of combustion I determined according to the engine operating condition is injected simultaneously from all cylinders in synchronization with the ignition timing [m・j
In an electronically controlled fuel injection system for internal combustion, which is designed to
The company is special in that the fuel injection timing is advanced and the fuel injection timing is advanced so that the fuel 1 whispers Q1 ahead of the ignition timing, thereby reducing the number of cylinders in which the injection fJJ combustion angle directly hits the spark plaque. (Electronically controlled fuel injection method for an internal combustion engine by Makidozu. Internal combustion (Ikuseki's electronically controlled combustion 8111 Riki Dekogawa method) as described in Section 1.