JPS5844232A - Fuel injection device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To avoid a trouble of unstable combustion, response delay, etc. in an engine, by increasing a number of injection times per one stroke of the engine at its cold time on the basis of temperature information of engine cooling water. CONSTITUTION:A controller 6 arithmetically outputs an electric conduction pulse width of solenoid valves, corresponding to an optimum fuel flow for loaded, speeded and warmed states of an engine, and fuel is injected to the engine 1 from the solenoid valves 7-10 in an intake manifold 2. After the engine is warmed, a pulse width Ti is calculated once in two revolutions of the engine, and injection is executed. However, at cold time of the engine, the pulse width Ti is calculated once in every revolution of the engine to execute injection, and response delay of the engine, resulting from a large friction loss of each slide rolling part of the engine at its cold time and from improper vaporization of fuel after injection, and/or unstable combustion, due to suction of liquid-state fuel, can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection device for an internal combustion engine that changes the number of times fuel is injected per stroke to the internal combustion engine according to the warm-up state of the engine. In the case of a multi-cylinder internal combustion engine, in order to simplify the circuitry of the injection device, the solenoid valves of each cylinder are driven to inject at the same time.
Generally, the injection is controlled to be performed once per revolution of the engine.

In the configuration of the device of the present invention, the fuel pressure supplied to the solenoid valve is always controlled to a constant pressure with respect to the intake pipe pressure ζ, and the geometrical shape of the solenoid valve itself is managed in a stacked manner to supply fuel to each cylinder. The amount is precisely proportional only to the time width of the injection pulse applied to the solenoid valve to achieve precise fuel supply accuracy, but within a range where the proportional relationship between the time width of the energization pulse to the solenoid valve and the fuel flow rate can be maintained. There is a physical upper and lower limit for 0 - In other words, in the case of the lower limit, current technology cannot provide accurate fuel supply at a pulse width of about 2 m or less due to the response delay of the solenoid valve, and on the upper limit side, the engine For example, at 6000 rpm, the solenoid valve completes the opening/closing operation in one rotation, so the maximum speed is 101a.
The valve cannot be opened beyond -.

On the other hand, there have been remarkable improvements in the performance of internal combustion engines in recent years, such as reduction of mechanical loss, which has led to a further reduction in the required fuel amount on the lower limit side, and due to installation of turbochargers, etc., the required fuel amount on the upper limit side has been reduced. Due to the above-mentioned physical limitations of the solenoid valve, it is no longer possible to accurately supply fuel to the entire operating range of the engine using the full-air injection system once per revolution.

As a solution to the above-mentioned problem, it is possible to change the conventional injection method of simultaneous injection in all cylinders once per revolution to simultaneous injection in all cylinders once per revolution, for example.

With this two-rotation one-time injection, whereas the conventional every-rotation injection divides the fuel necessary for each engine's combustion in one time into two parts, one injection gives one combustion ζ By providing all the necessary fuel and using an electromagnetic valve that injects twice the flow rate with the same lower limit pulse width, the range in which fuel can be measured can be nearly doubled.

As mentioned above, the two-rotation single injection is very advantageous in expanding the fuel metering range, but this method iζ has the disadvantages of the opposite method.

FIG. 1 shows an example of a sequence diagram in which conventional simultaneous injection at every revolution is applied to a four-cylinder, four-stroke engine, and FIG. 2 shows an example of a sequence diagram in which one-time injection in two revolutions is applied to the same engine.

As is clear from the hardening 1, simultaneous injection iζ every rotation in Fig. 1
Self-sealing is performed in synchronization with the intake timing of two of the four cylinders, and even if the engine load fluctuates midway, the injection pulse width can be updated every revolution based on new load information. . On the other hand, in the case of one injection per two revolutions as shown in Figure 2, the intake timing and injection pulse are synchronized in only one cylinder, and the remaining three cylinders take in the fuel that has been injected in advance near the intake valve at the intake port. It becomes a shape. In addition, even with load fluctuations, the information is updated only once every two revolutions, resulting in a dead time that is approximately twice as long as the injection at each revolution.The disadvantage of this sequence is that the engine combustion, It is mainly when the engine is cold that the actual damage to transient response becomes apparent. In other words, when the engine is cold, the temperature of the intake (-) and intake valve is low, and the fuel injected into the port cannot be sufficiently vaporized, so a large amount of liquid fuel will be sucked in, especially in one injection at two rotations. This results in unstable combustion and an increase in unburned harmful components in the exhaust gas. Regarding the transient response, for example, there is a large friction loss in the sliding parts of the engine when it is cold, and the poor vaporization of the fuel after injection as described above. Operation operations such as sudden opening of the throttle from low revolutions cause breathlessness and sluggishness, which is difficult to tolerate in terms of engine operability. The object of the present invention is to provide a fuel injection device for an internal combustion engine that solves the problems of the system and also satisfies the request for expanding the fuel metering range mentioned at the beginning.
According to the present invention, the range in which fuel can be measured is expanded by varying the number of injections of fuel per engine revolution when the internal combustion engine is cold or warmed up. According to an embodiment of the present invention, when a two-turn one-time simultaneous injection system is used for all cylinders, when the engine is cold, when problems occur with this system, the engine is Increase the number of injections per stroke - that is, for example - f22
The control is controlled to switch from injection at rotation 1 to injection at every rotation.Thus, the instability of -burning during cold operation,
Problems such as delayed engine response can be avoided.Furthermore, when the engine is cold, the electronically controlled fuel injection system to which the present invention is applied usually adjusts the fuel injection amount to, for example, 1. In order to control the amount to be increased by 3 to 1.5 times, the pulse width applied to the solenoid valve is naturally 1.3 to 1.5 times. ．．
It is possible to avoid the restriction of the minimum pulse width for energizing the solenoid valve, which is a problem with injection at every revolution.

Possible＠ ・Next, here is the attached drawing i, therefore, 1 of the fuel injection device according to the present invention.
% Example will be explained in detail. FIG. 3 is a block diagram showing eleven embodiments in which a known electronically controlled fuel injection device is applied to a four-stroke, four-cylinder engine. In FIG. 3, the internal combustion engine 1 includes an air cleaner (not shown), an air amount measuring device 3, and a throttle valve 1.
1. Inhale air via intake manifold 2 @Meanwhile,
Controller 6# includes the intake air amount meter 3, rotation detector 4, and engine cooling water temperature detector 5I! ! The signal will be emitted.

The controller 6 calculates and outputs the energization pulse width of the solenoid valve corresponding to the optimal fuel flow rate for the load, rotation speed, and warm-up state of the engine, and outputs the energization pulse width of the solenoid valve 7 disposed in the intake manifold 2.
From 8.9.10, fuel is injected into the engine 1.The intake air amount detector 3 is of a known type, such as a hot wire type, a double plate type, or a Karman vortex type, and the rotation detector 4 is, for example, a It is a known electromagnetic tsuquazzo or the like configured to emit a ζζ pulse for every engine revolution, that is, 660 degrees of crank angle, and the engine cooling water detector 5 is a known one that exhibits some kind of output characteristic with respect to temperature, such as a thermistor. Next, a processing method within the controller 6 according to the present invention in a fuel injection system having a configuration of 0 or more will be described with reference to FIGS. 4 and 5.

Figures 4 and 5 are flowcharts of the fuel injection calculation part embodying the present invention in digital control using a microprocessor, etc. Figure 4 is a schematic flowchart of a known digital one-engine control. The main routine program is step 201
- 206, various processes are performed and flow is performed. 1
01 is a 360° crank angle interrupt terminal, which is configured to perform calculations during the injection pulse every 3600 crank angle signal of the rotation speed detector 3 shown in Fig. 3.Next, the 360° crank angle interrupt terminal is The injection pulse width calculation process using the interrupt for each angle will be explained in detail. The f) embodiment of the present invention is disclosed in this 36o0 crank angle interrupt process. When entering the interrupt process, first in step 102, the output THw of the engine cooling water temperature detector 5 is set to the set temperature "if" stored in advance.
Compare with @"HW >"lll1F, that is, if the engine has warmed up, the process moves to step 103, and "HW
< ``When HW, that is, when cold, processing is Stella f.
Proceed to the side of 109.

First, to explain the process after warm-up, step 103 is a flag inversion process, and the process passes through step 103. Each time, the flavum is reversed from 0 → 1.1 → 0. That is, the flavum in step 103 is reversed from 0 to 1 to 0 to 1 every 360° crank angle. Next, in step 111, it is determined whether this frabum is 1 or 0, and if it is frabum RO, the interrupt processing is terminated without executing anything.◎Fragmumi 1
If so, the process proceeds to step 104; that is, the processes from step 104 onwards are executed every other interrupt, 1720 degrees 0 mm, or once every two revolutions of the engine. Step 104 is a process for determining the basic injection pulse width TP, and TP is determined, for example, by calculation from the intake air amount and rotational speed signals, or by searching from a map stored in advance. Although not particularly shown in the figure, correction of the basic injection pulse width according to the intake air temperature is also performed as necessary at this stage.

The basic injection pulse width obtained in step 104 is multiplied in the Stella f105 for correction such as warming-up increase according to the cooling water temperature, and in step 106, the power supply voltage is corrected as necessary due to the unique characteristics of the solenoid valve. Known corrections such as correction and addition of invalid injection time and the like are added. Through these steps, the final energization pulse width T1 to the solenoid valve is determined, and is output from the output port 107 connected to the solenoid valve drive circuit (not shown), thereby terminating the interruption. Above steps 101.102.1
03.111.10'4.105.106.107.1
By the process connected to 08, after the engine is warmed up, the pulse width T1 is calculated once every 21 rotations of the engine, and the injection is executed. Cooling water temperature determination step 102
te) If <”*vt □Processing proceeds to step 109. Step 109 is the basic injection pulse width 'T
This is the arithmetic processing of P, and to simplify the program, the existing kv
It is preferable to make this step common to step 104 described above. However, it is determined in step 104? , is the basic injection pulse width in the case of one injection in two revolutions, so it cannot be directly applied as the 1Δlus width' for injection in each revolution during cold operation.

Therefore, in step 110, 7. Divide by %. Below are steps 10Ss from correction to output and end of interrupt.
1 O6,10? , 108 are exactly the same as after warm-up. Above steps 101.102.10'j,
-104, 110, 105, 106, 107, and 108, when the engine is cold, the pulse width T1 is calculated once every 360° crank angle, that is, every engine rotation, and injection is executed.

In addition, in the above-mentioned embodiments, what is the temperature when cold? , were determined by steps 109-104, which performs common arithmetic processing after warm-up, and step 110, which performs can processing. It is optional to provide a separate step 112 for performing arithmetic processing.

Further, although the embodiment discloses that some kind of intake air amount detector is used to calculate IrP, the present invention may be combined with any known method of determining TP from engine intake pipe pressure, throttle opening, etc. A desired effect can be obtained.

Furthermore, in this embodiment, the rotation speed detector was constructed of a type that generates a pulse signal every 3600 crank angles.
In combination with the predetermined 3600 crank angle counting process, it is possible to generate, for example, a 30° 60° 180° crank angle signal, or even use an ignition primary signal. In this embodiment, a cooling water temperature detector is used, but in the case of an air-cooled engine, for example, a method of detecting the cylinder head temperature or lubricating oil temperature may be used instead. Although this embodiment has disclosed the case where the injection pulse width calculation is digitally processed, the present invention can also be applied to a known analog type fuel injection device. In this case, if the present invention is applied to the circuit of the known simultaneous injection device for every revolution of a 4-cylinder 4-stroke engine, the r-t circuit that compares the output of the cooling water temperature signal with a certain comparison level will be used only during engine warm-up. By roughly dividing the % frequency division output of the ignition primary signal whose calculation trie is h into h, it is possible to achieve the same operating effect as in the embodiment of the present invention.

In addition, the type of engine is not limited to the 4-cylinder engine disclosed in this embodiment, but the present invention can be applied to 6-cylinder and 8-cylinder engines without any problem. Solenoid valve 7
In addition to the method of arranging ~1◎, BPX (single/f
The present invention can be applied to any system in which one or more solenoid valves are arranged in the intake pipe convergence section called Indian injection, and in that case, 111 or 2
It is also possible to configure the fuel injection valve to perform multiple fuel injections.As described above, according to the present invention, the fuel injection valve can be This has the effect that the pulse width variation range of the applied drive pulse signal can be substantially expanded.

[Brief explanation of drawings]

Fig. 1 is a sequence diagram showing the injection timing of conventional simultaneous injection every revolution, Fig. 2 is a sequence diagram showing the injection timing of one injection in two revolutions, and Fig. 3 is a system configuration block disclosing an embodiment of the present invention. Figures 4 and 5
The figure is a flowchart showing the operation of an embodiment of the apparatus of the present invention. 1... Engine body 2... Intake manifold 3...
Intake air amount meter 4...Rotation detector 5...Cooling water temperature detector β...Controller (arithmetic circuit)

Claims (1)

[Claims] (1) In a fuel injection device for an internal combustion engine that calculates the optimal fuel injection amount using a signal synchronized with the rotation of the internal combustion engine and simultaneously injects fuel into each cylinder in synchronization with the stroke of the engine,
A detector that detects the warm-up state of the engine and a detection signal from the detector are input, and the number of fuel injections per engine revolution can be varied depending on whether the engine is cold or warm. 1. A fuel injection device for an internal combustion engine, comprising a control means for controlling the fuel injection device. (21) As for the control means, when it is determined that the engine is in a warm-up state, the number of fuel injections is set to one injection per two revolutions of the engine, and when it is determined that the engine is in a cold state, the number of fuel injections is set to one time per two revolutions of the engine. A fuel injection device for an internal combustion engine as claimed in claim 1, characterized in that the fuel injection device for an internal combustion engine is configured to control the rotation so that one injection occurs.