JPS61152936A - Start-up system of engine - Google Patents

Abstract

PURPOSE:To make it always possible despite fluctuation of engine temperature to judge completion of correct explosion by detecting the engine speed at the time of start-up and changing the revolving speed serving as the basis for the judgement of the completion of an explosion in accordance with the temperature of cooling water. CONSTITUTION:A valve opening adjusting device 5, designed to adjust the opening of the throttle valve 2 of a carbureter 1, and a fuel injecting device 4 are controlled through a command controlling device A. At the time of start-up, fuel injection quantity and the opening of the throttle are controlled to become suitable for the state of operation during cranking and after the completion of an explosion. The completion of an explosion is judged when the actual engine speed entered by means of an engine speed detecting device 6 is detected to surpass a judgement base value through an explosion completion judgement device B. And the judgement base value of an explosion completion judgement device B is altered in accordance with the temperature of cooling water through an explosion completion judgement base value alteration device C which receives signals from a water temperature detecting device 7. Accordingly, it becomes possible to give correct judgement on the completion of an explosion in conformity to the temperature of cooling water.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a starting system mainly applied to an automobile engine.

[Prior Art] Gasoline engines require a particularly rich air-fuel mixture when starting, so they are generally equipped with a choke system as a starting system. However, in the choke system, it is essential to provide a choke valve within the carburetor and also to include a mechanical structure such as a link mechanism for manually or automatically opening and closing the nozzle. Therefore, the structure of the fuel supply system inevitably becomes complicated, which is an obstacle to simplifying the structure of the engine as a whole.

As a prior art of a starting system developed to deal with such inconveniences, the patent application No. 58-2376 filed earlier
There is one as shown in Publication No. 32. That is, this starting system includes a fuel injection means that supplies an amount of fuel corresponding to an injection command signal, a valve opening adjustment means that moves the closing position of the throttle valve according to the opening/closing command signal, and a valve opening adjustment means that adjusts the engine rotation speed. A complete explosion that successively compares the detected value by the rotational speed detection means with a complete explosion determination value and outputs a complete explosion completion signal when the detected value exceeds the complete explosion determination value. A determination means, and a command N4 @ means for switching the injection command signal and the opening/closing command signal from those for cranking to those for after complete explosion on the condition that the complete explosion determination signal is output. It will be done.

With this kind of device, you can obtain the refueling amount and idle throttle opening that are appropriate for the operating condition during cranking and after the completion of the complete explosion, but with the conventional type, the above-mentioned complete explosion is possible. The judgment value is set to a constant value. However, since the complete explosion rotational speed when actually starting the engine tends to decrease as the water temperature becomes lower, if the complete explosion determination value is fixed to a constant value, there is a possibility of an erroneous determination. In other words, if the complete explosion judgment value is set to a relatively high value, if the water temperature becomes lower than expected, the complete explosion judgment will be made even though the actual engine speed has reached the complete explosion speed. What is not done can happen. In this case, the fuel injection amount and throttle opening are maintained at those for cranking, and even after the starter is stopped, an irregular continuous firing condition accompanied by vibration and noise occurs. may continue.

Such a problem can be prevented by setting the complete explosion determination value to a sufficiently low value, but if this is done, other problems will occur. That is, the engine speed during cranking varies greatly depending on the engine cooling water temperature and the state of charge of the battery, and if the conditions are impaired, it may increase to about 40 rpm, for example. Therefore, if the above-mentioned complete explosion determination value is set to a too low value, there is a risk that a complete explosion will be determined during cranking.

[Problems to be Solved by the Invention] The present invention solves at once the problem that setting the complete detonation determination value to a high value will lead to repeated detonations, and setting it to a low value will result in incorrect determination of complete detonation. The purpose is to

[Means for Solving the Problems] In order to achieve the above objects, the present invention is characterized in that the complete explosion determination value is adjusted in accordance with the engine cooling water temperature. .

That is, the engine starting system according to the present invention includes a fuel injection means (4) that supplies an amount of fuel corresponding to an injection command signal to an intake system, and a closing position of a throttle valve (2) that moves in accordance with an opening/closing command signal. Valve opening adjustment means (
5) and water temperature detection means (
7) and a rotation speed detection means (
6), and a complete explosion determination that successively compares the detection value by the rotation speed detection means (6) with the complete explosion determination value and outputs a complete explosion completion signal when the detected value exceeds the complete explosion determination value. Means CB
), a command control means (A) for switching the injection command signal and the opening/closing command signal from those for cranking to those for after complete explosion on the condition that the complete explosion completion signal is output; Complete explosion judgment value changing means (C
).

[Function] According to this configuration, a complete explosion is determined during cranking based on the complete explosion determination value, and if the engine speed does not exceed the complete explosion determination value, the A fuel injection command signal and an opening command signal are output to the fuel injection means, and when the value exceeds the complete explosion determination value, a fuel injection command signal and an opening command signal for after the complete explosion are output to the fuel injection means. and is output to the opening adjustment means. The complete explosion determination value is changed depending on the temperature of the engine cooling water. Therefore, if this change pattern is carefully set in advance, no matter how the engine water temperature changes, it is possible to always make a complete explosion determination using the optimal complete explosion determination value.

[Embodiment] An embodiment of the present invention will be described below with reference to Figs. 2 to 7. Fig. 2 is an explanatory diagram of an engine starting system according to the present invention, and 1 in the figure is a carburetor of an automobile engine. 2 is a throttle valve of this carburetor L, 3 is a float chamber, 4 is a fuel injection means for supplying an amount of fuel corresponding to the injection command signal a into the carburetor 1 forming a part of the intake system, and 5 is a Valve opening adjustment means for moving the closing position of the slow 2 torque valve 2 in accordance with the opening/closing command signal; 6, rotation speed detection means for detecting the engine rotation speed; 7, water temperature detection means for detecting the engine cooling water temperature. It is. Reference numeral 10 denotes a microcomputer system that serves as command control means A, complete explosion determination means B, and complete explosion determination value changing means C.

The fuel injection means 4 has an inlet 12 having a check valve 11 connected to the float chamber 3 via an in-left passage 13, and an outlet 14 connected to the carburetor 1 through an outlet passage 16 having a check valve 15. The fuel injection pump 10 is equipped with an electromagnetic refueling pump (SAP) 17 opened to the intake passage 1a of the engine, and a driver 18 that receives an injection command signal supplied from the microcomputer system IO. The refueling pump 17 accommodates a piston 22 in a cylinder 21 forming a pump i19, and performs a pump function by moving the piston 22 forward and backward by the urging force of a spring 23 and the electromagnetic attraction force of a solenoid 24. It is composed of The driver 18 applies a pulse voltage to the solenoid 24 to move the piston 22 of the refueling pump 17 forward or backward, and changes the pulse period of the applied voltage to move the piston 22 of the refueling pump 17 forward or backward. The amount of fuel discharged can be adjusted. That is, by applying one pulse of driving voltage to the solenoid 24 of the refueling pump 17, the piston 22
A fixed amount (for example, 0.04 cc) of fuel is discharged from the refueling pump 17 each time the refueling pump 17 makes one reciprocating operation. Therefore, when the pulse period FH2 is increased, the pulse interval becomes longer and the amount of fuel discharged per unit time decreases, and conversely, when the pulse period FHz is decreased, the pulse interval becomes shorter and the amount of fuel discharged per unit time decreases.
1 is increasing.

On the other hand, the valve opening adjusting means 5 includes an actuator 25 that locks a rotating arm 2b integrally protruding from the support shaft 2a of the throttle valve 2, and an actuator 25 that moves the actuator 25 forward and backward to open the throttle valve 2. DC motor 2 for moving the closed position
6, and a driver 27 that applies a DC voltage to the DC motor 26 in a pulse manner to operate the DC motor z6 by an amount corresponding to the opening/closing command signal. To be more specific, the actuator 25 is shaped like a cap nut, and is screwed onto a feed screw portion 26b provided on the output shaft 26a of the DC motor 26 while its rotation is prohibited by a guide member (not shown). The rotary arm 2b of the throttle valve 2 can be locked at its tip. In addition, 2c
2d is a spring that biases the throttle valve 2 in the opening direction; 2d is a spring that opens the throttle valve 2 in response to depression of an accelerator pedal (not shown); and the microcomputer system 10.

Central @ arithmetic processing? cfi 28, memory 29, and interfaces 31 and 32. At least the signal C from the rotation speed detection means 6 and the signal d from the water temperature detection means 7 are input to the interface 31, and the valve opening adjustment means 5 and the fuel injection means 4 are input from the interface 32 to the signal C from the rotation speed detection means 6 and the signal d from the water temperature detection means 7, respectively. The signals a and b are outputted toward the target. The rotational speed detection means 6 is for detecting the rotational speed of the engine, and uses, for example, an ignition pulse. X, water temperature detection means 7
is for detecting the engine cooling water temperature, for example, a thermistor that converts the water temperature into an analog electrical signal,
It includes an A/D converter (not shown) that converts the output of the thermistor into an electrical signal.

And, the microcomputer system IO has the following:
In a pro step 51 as schematically shown in FIGS. 3a and 3b, the engine rotation speed N detected by the rotation speed detection means 6 and the engine cooling water temperature T detected by the water temperature detection means 7 are input. 0 then step 52
In step 53, whether or not the engine is stopped is determined based on the engine rotation speed N. If it is determined that the engine is stopped, the process proceeds to step 53; if it is determined that the engine is not stopped, The process proceeds to step 54. In step 53, the fuel injection means 4 is stopped. on the other hand,
If the process proceeds to step 54, the engine speed N
is equal to or greater than the complete explosion determination value TSTRT. The complete explosion determination value TSTRT is set to vary depending on the engine cooling water temperature. That is, the optimal complete explosion determination value TSTRT corresponding to each engine cooling water temperature is selected in advance, mapped, and stored in the memory 29.

At step 54, a complete explosion judgment value TST corresponding to the detected water temperature is set.
The RT is read from the map and a complete explosion is determined. In addition, in the explanation, when the engine speed N is higher than the complete explosion judgment value TSTRT, the internal processing of the computer is to determine the interval between detected ignition pulses indicating the engine speed N and the ignition pulse corresponding to the complete explosion judgment value. A complete explosion is determined by comparing the interval between the two. Therefore, as shown in FIG. 7, the memory 29 stores a map of the ignition pulse interval (5ea) for determining complete explosion according to the engine cooling water temperature T. With this setting, the lower the engine cooling water temperature T, the lower the complete explosion determination value TST.
The R position is changed to the low rotation side (the side where the ignition pulse interval becomes longer). The result of such determination at step 54.

If it is determined that the engine speed N is not equal to or higher than the complete explosion determination value TJTRT, the process proceeds to step 55, where the complete explosion determination value TS
If it is determined to be above TRT, it is determined that a complete explosion has occurred and the process moves to step 56. In step 55, the cycle value FSIEItFNK for cranking is set as the drive cycle FH2 of the refueling pump 17, and the process proceeds to step 57. As shown in FIG. The relationship with the optimal drive cycle of the replenishment pump 17 is selected in advance and made into a map. In addition, the correction coefficient FNE is used to prevent the air-fuel ratio from being disturbed due to variations in cranking rotation speed, and as shown in Figure 5, the optimum value is selected in advance according to the level of cranking rotation speed. It is mapped. Further, when a complete explosion is determined in step 54 and the process proceeds to step 56, a cycle value 5FWL for after complete explosion is set as the drive cycle FNE of the refueling pump 17. Period value 5FWL for after complete explosion
As shown in FIG. It is determined whether or not it is equal to or greater than 400 seconds, and if it is equal to or greater than 400 seconds, the process proceeds to step 53 and the refueling pump (SAP) 17 is stopped. On the other hand, if it is determined that the period value FIZ is less than 400 m5ec, the process moves to step 58, and this period FH
At step 2, the engine outputs the tuna and the 179H tuna + λ buttocks. Next, the process proceeds to step 71 shown in FIG. If the engine speed N is less than the determination value TSTRT, the process moves to step 72, while if the engine speed N is less than the complete explosion determination value TSTRT, the process proceeds to step 7.
Move on to 3. In step 72, the target throttle opening TA
As a GET, the throttle opening value θl (for example, 5'') for non-complete explosion is set, and the process moves to step 81. On the other hand, in step 73, it is determined whether a certain period of time, for example, 5 seconds has elapsed from the time of determination of complete explosion. If 5 seconds have not elapsed since the complete explosion determination, the process proceeds to step 74; if 5 seconds have elapsed, the process proceeds to step 82. In step 74, the first idle rotation speed is set as the target throttle opening TAGET. Correspondingly, a predetermined throttle opening degree θ2 for complete explosion is set, and the process moves to step 81.Step 8
1, throttle opening prospective control is implemented in which the valve opening adjustment means 5 is driven so that the difference between the actual closing position of the throttle valve 2 and the target throttle opening TACET falls within a certain tolerance value. Step 5
Return to 1. On the other hand, if the process moves to step 82 after 5 seconds have elapsed since the complete explosion determination, the actual engine speed N converges to the preset target idle speed according to the water temperature and the 0N-OFF state of the air conditioner. Idle rotation speed control is executed to drive the valve opening adjustment means 5, and the process returns to step 51. The above procedure is then repeated while the ignition switch is on.

With such a configuration, during cranking, F is set as the refueling pump drive period FH2 in step 58.
As the SEI book FNE is set, step 72
Since θl is set as the target throttle opening TAGET, the closed position of the throttle valve 2 controlled by the valve opening adjusting means 5 is maintained at θ1 (5°), and the fuel in the fuel injection means 4 is The replenishment pump 17 is driven at a cycle FSECFNE. Therefore, when a relatively large amount of fuel is supplied to the engine and the engine shifts to complete explosion operation, SFwL is set as the refueling pump driving cycle FH2 in step 57, and the target throttle opening TAGET is set in step 74. is updated to 02, and the DC motor 26 of the valve opening adjustment means 5 is operated to shift the closed position of the throttle valve 2 to the opening position corresponding to the first idle rotation speed.

As shown in FIG. 7, the complete explosion determination value TSTRT is shifted to a lower rotational speed side (to a side where the ignition pulse interval becomes larger) as the detected water temperature becomes lower. Therefore, with this kind of engine, even if the actual number of complete explosion revolutions varies depending on the temperature of the engine cooling water, the complete explosion judgment value 5
TRT is also adjusted to an optimal value in accordance with the water temperature. Therefore, it is possible to always make an appropriate complete explosion judgment,
A smooth transition can be made from control during cranking to control after complete explosion. Therefore, even though the actual engine speed has reached the full explosion speed, a complete explosion judgment is not made, resulting in unpleasant repeated explosions, or because the complete explosion judgment value is set on the low rotation side. This can effectively eliminate the inconvenience of erroneously determining a complete explosion during cranking.

Note that the configurations of the rotational speed detection means and the water temperature detection means are of course not limited to those of the above-mentioned embodiments, and various modifications can be made without departing from the spirit of the present invention.

Furthermore, in the above embodiment, a case was explained in which the optimal complete explosion judgment value according to each water temperature was selected and mapped.
Of course, the present invention is not limited to such a thing.1 For example, a relational expression between water temperature and an optimal complete explosion determination value may be stored, and a complete explosion may be determined as appropriate based on the detected water temperature'. A determination value may also be calculated.

[Effects of the Invention] Since the present invention has the above-described configuration, it is possible to easily bring the engine to a complete explosion even if the choke mechanism is abolished, and moreover, even if the engine cooling water temperature fluctuates. We also provide an engine starting system that can properly determine complete explosion.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram for clearly explaining the present invention. 2 to 7 show an embodiment of the present invention, FIG. 2 is a system explanatory diagram, FIGS. 883a and 883b are flowcharts, and FIG.
Figures 5, 6, and 7 are explanatory diagrams for explaining control setting conditions. l... Carburetor 2... Throttle valve 4... eFuel injection means 5... Valve opening adjustment means 6... Rotation speed detection means 7'11... Water temperature detection means 10... Microcomputer System A...Command control means B...Complete explosion determination means C...Complete explosion determination value changing means

Claims (1)

[Claims] A fuel injection device that supplies fuel in an amount corresponding to the injection command signal to the intake system, a valve opening adjustment device that moves the closing position of the throttle valve in response to the opening/closing command signal, and a water temperature detection device that detects the engine cooling water temperature. means, a rotation speed detection means for detecting the rotation speed of the engine, and a detection value by the rotation speed detection means and a complete explosion judgment value are successively compared, and when the detected value exceeds the complete explosion judgment value, a complete explosion is detected. a complete explosion determination means for outputting a complete explosion signal; and on the condition that the complete explosion completion signal is output, the injection command signal and the opening/closing command signal are changed from those for cranking to those for after the complete explosion. An engine starting system comprising: a command control means for switching; and a complete explosion determination value changing means for changing the complete explosion determination value in accordance with a detected value of the water temperature detection means.