JPH0748992Y2 - Engine fuel controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a fuel control device for an engine.

[Conventional technology]

Conventionally, the following is known as a control means for preventing overheating of an engine (especially overheating of an exhaust system).

A) The engine temperature is detected, and the fuel supply amount is increased when the detected temperature is higher than a predetermined temperature (refer to Japanese Patent Laid-Open No. 59-203834).

B) The temperature of the cooling water is detected, and if the detected temperature becomes higher than a predetermined value, the cooling fan is operated (JP-A-58-19).
2917 publication).

[Problems to be solved by the device]

In order to avoid the overheated state of the engine more reliably, it is preferable to combine the fuel increase of A) and the cooling fan operation of B). However, if the fuel amount A) is unnecessarily increased, there is a disadvantage that fuel consumption and emission are significantly deteriorated.

Incidentally, Japanese Patent Laid-Open No. 61-53431 discloses that the fuel amount is increased after a lapse of a predetermined time from the detection of a high load state in which the exhaust system may overheat. The "predetermined time" is set to the time it takes for the engine to actually reach the high temperature state from the time when the high load state is detected, and in the end, the high temperature state of the engine is simply detected. It is virtually the same as the control of.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an engine fuel control device capable of reliably preventing engine overheating while suppressing fuel increase.

[Means for Solving the Problems]

As a means for solving the above problems, the present invention provides an electric fan, a temperature detecting means for detecting a temperature related to an engine temperature, and an electric fan drive for driving the electric fan when the temperature detected by the temperature detecting means is a predetermined value or more. In the fuel control device for the engine, the operating time is set based on the operating time detecting means for detecting a parameter related to the operating time of the electric fan, and the parameter detected by the operating time detecting means. And a control means for increasing the fuel supply amount when the time is exceeded.

[Action]

According to the above configuration, the degree of the high temperature state can be grasped by detecting the parameter related to the operating time of the electric fan driven only in the high temperature state, and the fuel control can be performed according to this degree. That is, even in the same high temperature state, if the operating time of the cooling fan that is driven correspondingly is short, that is, if the high temperature state can be avoided within a short time by cooling with the cooling fan, refraining from increasing the fuel amount while cooling. When the fan operating time reaches the set time, that is,
When the high temperature state is not avoided even after the cooling fan is operated for the set time, the engine cooling is assisted by increasing the fuel amount, whereby the engine overheat can be more reliably avoided and the operating time of the cooling fan can be shortened.

〔Example〕

In FIG. 1, in the intake passage 2 to the engine body 1,
An air cleaner 3, an air flow meter 21 for detecting the amount of intake air, a throttle valve 4, a surge tank 22, and an injector 5 are arranged in this order from the upstream side. Further, the intake passage 2 is provided with a bypass passage 23, and this bypass passage 23 is provided with
An ISC (Idle Speed Control) valve 24 is provided.
By adjusting the opening / closing of the SC valve 24, the amount of air is adjusted in order to adjust the engine speed during idle rotation and to correct the effect of the load on the alternator during operation of the air conditioner and the electric fan 8.

The intake passage 2 and the engine body 1 are provided with a throttle opening sensor 41 for detecting the opening of the throttle valve 4, an intake temperature sensor 25 for detecting the intake air temperature, and a water temperature sensor 11 for detecting the engine cooling water temperature. Has been. Further, an O ₂ sensor 61 for detecting the air-fuel ratio, an exhaust manifold 6, a rotation speed sensor 71 for detecting the rotation speed of the engine, a distributor 7 of the ignition device, and a crank angle sensor for detecting the crank angle.
12 are provided on the camshaft 13, respectively.

The electric fan 8 for cooling the radiator 81 is connected to the battery 82 via a relay (electric fan driving means) 83,
The relay 83 is configured to be turned on by a water temperature switch (temperature detecting means) 14 provided in the engine body 1. That is, the water temperature switch 14 is operated when the engine cooling water temperature reaches a predetermined temperature (for example, 96 ° C).
The electric fan 8 is configured to be turned on and turned off at the predetermined temperature or lower, and the electric fan 8 is operated when the water temperature switch 14 is turned on.
Stop at F.

Water temperature sensor 11, crank angle sensor 12, water temperature switch
The air flow meter 21, the intake air temperature sensor 25, the throttle opening sensor 41, the O ₂ sensor 61, and the rotation speed sensor 71 are connected to a control unit (ECU: control means) 9. The control unit 9 counts the duration of the ON state of the water temperature switch 14 with a timer or the like as a parameter related to the operating time of the electric fan 8, and the sensors 11, 12, 21, 25, 41, 61.71. The fuel injection amount from the injector 5 and the opening / closing of the ISC valve 24 are controlled based on the detection signal from the. Specifically, the fuel amount increase correction at the time of high load is made to correspond to the operating time of the electric fan 8, and after confirmation by the cooling water temperature and the intake air temperature, the fuel amount is increased or decreased sequentially. .

The control of the control unit 9 is shown in FIGS.
It will be described with reference to the drawings. In step S ₁ , the engine speed Ne and the air amount Qa are read, and in step S ₂ , the basic pulse Tp is obtained by multiplying the air amount Qa divided by the engine speed Ne by a coefficient K. Then, in step S ₃ , the water temperature Thw of the cooling water of the engine body 1 and the intake air temperature Tha are read, and in step S ₄ , the warm air increase value Cw based on the water temperature Thw is read.
In addition, various increase correction values such as the acceleration increase value are calculated.

Next, in step S ₅ , it is determined based on the throttle opening degree, the rotation speed Ne, and the like whether or not the operating state is in the rich zone, which is a high load, high rotation region.

Is set to "0" in the high water temperature increase execution flag Xcer2 in step S _6, if not the enriched zone, the basic enrich increase value Cer1 and the additional enriched increase value in the step S ₇ Cer2
And 0. And determining whether the or a feedback (F / B) zone in the starting zone of the region other than the enriched zone in step S _8. If the F / B zone based at Step S ₉ output from the O ₂ sensor 61 F / B correction value C
transition from calculates the fb to step S _11, also shifts the F / B correction value Cfb if not in F / B zone (s) to zero in step S _11.

Step S At ₁₁ and the base enriched increase value Cerl adds the additional enrichment increase value Cer2 with enriched boost value Ce
seeking r, the enrichment increase value Cer in step S _12, F / B
Adding and correction value Cfb and various correction values obtained in step S ₄ obtains the total correction value Ctota1 with. Step S ₁₃
Then, the effective injection time Te is obtained by multiplying the total correction value Ctota1 by the basic pulse Tp. In step S ₁₄ reads the battery voltage VB, the invalid injection time Tv on the basis of the voltage value VB
Ask for. In step S ₁₆ the effective injection time Te
And the invalid injection time Tv are added to obtain the final injection time Ti,
By outputting this to the injector 5, the amount of fuel corresponding to this final injection time Ti is injected. Note the step S ₁₄ to S _16, in consideration of the influence of the opening delay of the time the injection in the injector 5, the final this by asking the ineffective injection time Tv on the basis of the voltage value VB that correlates with the opening delay It is included in the injection time Ti. Step S ₆ to S ₁₆ indicates the fuel control from the injector 5 when not enriched zone.

If you are in the enriched zone in step S ₅ , step
In S ₁₇ , the basic enrichment value Cer1 is calculated based on the rotation speed Ne and the basic pulse Tp. Next, in step S ₁₈ , the water temperature T
Determine whether hw is above the set temperature (for example, 80 ℃),
Unless more, added in step S ₁₉ Enrich increase value C
The er2 is set to 0 the process proceeds to step S _11. In this case,
For additional enrichment increase value Cer2 is 0, the value of only the basic enriched increase value Cer1 is used as the final enriched boost value Cer in step S _11.

If the water temperature Thw is 80 ° C. or higher in step S ₁₈ , it is further determined in step S ₂₀ whether the intake air temperature Tha is the set temperature (eg, 30 ° C.) or higher. In this way, considering the state of the intake air temperature Tha over the water temperature Thw is because the cooling effect due to this can be expected if the intake air temperature Tha is low even if the water temperature Thw is high. This is because it is considered that the conditions affecting sexuality are not so severe.
Therefore unless the intake air temperature Tha is 30 ° C. or higher, the process proceeds to step S _19, additional enrichment boost value Cer2 in this step S ₁₉ is zero.

Higher the intake air temperature Tha in step S _20, step S ₂₁
Determines whether the electric fan flag Xfan is "1" indicating the operating state, and whether the set time has elapsed after the electric fan flag Xfan changed from "0" indicating the stop state to "1". To do. That is, it is determined whether or not the water temperature is 96 ° C. or higher and the electric fan 8 is operated, and whether the operation is continued for the set time, and the electric fan 8 is operated and the set time is elapsed. If
Sets "1" in step S ₂₂ to the high water temperature increase execution flag Xcer2.

The constant fuel increase value to the previous additional enrichment boost value Cer2 Step S Additional enrichment boost value Cer2 At ₂₃
Set the value obtained by adding the Ker1, In step S ₂₄ the set additional enriched boost value Cer2 and fuel increase upper limit guard value
Compare with Ker2MAX and set the smaller value as the additional enrichment value Cer2. This additional enrichment increase value Ce
By adding the r2 basic enriched increase value Cer1, determine the enrichment increase value Cer in step S _11. Hereinafter, steps S ₁₂ to S based on the enrichment increase value Cer
Performs ₁₆ processes. As a result, the amount added by the basic amount increase correction value is increased.

In step S _21, "0" electric fan flag Xfan, i.e. Ya case when the electric fan 8 is stopped continues, the or once the electric fan 8 and heated up to the upper limit condition is stopped after the operation , whether the electric fan flag Xfan is "1", i.e., for example, when actuated continuous operating time of after does not exceed the set time, the high water temperature increase execution flag Xcer2 in step S ₂₅ is "1" To determine. That control to add in addition to increasing the addition of basic enriched increasing correction (step S ₂₂ to S _24, step S ₁₁ reference) it is determined whether the taking place up to the previous time, the step S ₁₉ if it is not done Continue to add additional enrichment value C
The er2 determine the enrichment boost value Cer in step S ₁₁ to 0, the process proceeds to step S ₂₆ if the control is performed.

In step S _26, the electric fan flag Xfan determines whether elapsed set time turned into "0" from "1", if the set time continues to the stop state has returned already low water temperature In step S ₂₇ , the high water temperature execution flag is returned to “0”, in step S ₁₉ , the additional enrichment value Cer2 is set to 0, and in step S ₁₁ , the enrichment increase value Cer is set based on the additional enrichment value Cer2. decide. Unless the set time has elapsed, the previous additional enrichment increase value added Enriched increase value Cer2 step S ₂₈
The value obtained by subtracting the constant fuel subtraction value Ker2 from CER2, additional enrichment boost value Ce calculated in step S ₂₈ in step S ₂₉
r2 is compared with 0, which is the lower limit guard value, and the larger value is determined as the final additional enrichment amount Cer2. Based on this additional enriched boost value Cer2, the enriched boost value
Cer is determined in step S ₁₁ .

In the above configuration, when the operating state is in the enrichment zone, first, the basic enrichment value Cer1 of the enrichment value Cer is set in the same manner as the conventional one (step S ₁₇
See), and in terms of the temperature Thw and the intake air temperature Tha are both confirmed that higher than the predetermined temperature (see step S _18, S _2), if the operation time of the electric fan 8 is longer than the predetermined time, the exhaust system It is determined that the thermal conditions such as will be severe, and the addition of the additional enrichment increase value Cer2 to the above basic enrichment increase value Cer1 is the enrichment increase value Cer,
The fuel amount is increased based on this.

As a result, in addition to the normal fuel increase correction (correction based on the basic enrichment increase value) during enrichment, special increase correction (correction based on the additional enrichment increase value) can be performed, and the thermal conditions of the exhaust system etc. can be relaxed. Can be achieved.
Moreover, since the thermal conditions are alleviated, the frequency of operation of the electric fan 8 can be reduced, and the generation of noise can be suppressed.

Further, in this embodiment, the upper limit value is not added immediately as the above-mentioned special amount increase correction, but a constant value Ke is reached until the upper limit value (fuel increase upper limit guard value Ker1) is reached.
gradually increases by r1 (see step S _23, S _24). As a result, the amount can be increased in accordance with the thermal conditions that become more severe with the passage of the operating time, and the amount can be increased efficiently and economically as compared with the case where the fuel of the upper limit value is added immediately.

Even if both the water temperature Thw and the intake air temperature Tha are higher than the predetermined temperature, if the operating time of the electric fan 8 is shorter than the predetermined time, it is determined that the thermal condition is not so severe as to perform the special increase correction. , normal increase correction based on the basic enriched increase value is performed as enrich increasing correction (see step _{S 21, S 25, S 19} , S 11).

Further, when the operation of the electric fan 8 is stopped after the special increase correction is performed, and if the duration of the stopped state is longer than the predetermined time, it is determined that the water temperature is already kept low. and the additional enriched increase value Cer2 immediately 0 (see steps _{S 26, S 27, S 19} ) is still water temperature is shorter than the predetermined time is determined that it is not already so low in the additional enriched bulking Value Ce
without immediately zero r2, gradually reduced by a constant value Ker2 (see steps _{S 26, S 28, S 29} ). As a result, when the operation stops once after the operation reaches the upper limit state and the remaining time has not elapsed, the additional enrichment increase value Cer2 is added in accordance with the water temperature that decreases with the elapse of the stop time.
Can be sequentially reduced. As a result, when the water temperature is decreasing from the upper limit value, it can be immediately dealt with even if the water temperature changes to an operating state where the water temperature rises again. Can be reduced.

Note if the operating condition is not in Enrich zone, normal F / B control, except the starting zone (see step S ₇ to S ₁₆₎ is performed.

As described above, in this embodiment, in the operating region in the enrichment zone, the fuel is increased based on the normal basic enrichment increase value Cer1 when the thermal conditions are not so severe, and when it becomes severe, the basic enrichment increase is performed. Value Cer1
Since the fuel can be increased based on the value obtained by specially adding the additional enrichment value Cer2 to the above, the above-mentioned thermal conditions can be relaxed, and thereby the thermal durability of the exhaust system etc. is not impaired. The reliability of the engine can be secured. Moreover, by relaxing the above-mentioned thermal conditions, it is possible to reduce the frequency of operation of the electric fan 8 and thereby suppress the generation of noise.

In the above embodiment, the water temperature switch 14 is used as a means for detecting a parameter related to the operating time of the electric fan 8,
Although it is configured to count the continuation of the ON state of the water temperature switch 14 by a timer, the present invention is not limited to this, and is configured to detect by counting the continuation of the ON state of the relay 83, for example. May be.

[Effect of device]

As described above, the engine fuel control device of the present invention detects the operating time of the electric fan driven at high temperature, and increases the fuel amount when the operating time reaches the set time. Therefore, in a high temperature state where it can be avoided by operating the cooling fan for a short time, refrain from increasing the fuel amount to avoid deterioration of fuel efficiency and emission, while increasing the fuel amount in a high temperature state that cannot be avoided even if the cooling fan is operated for the set time. You can run it more reliably to prevent overheating of the engine,
In addition, the operation time of the cooling fan can be shortened.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of the present invention, FIG. 2 is a flow chart showing control by a control unit, and FIG. 3 is a flow chart showing a continuation of FIG. DESCRIPTION OF SYMBOLS 1 ... Engine main body, 5 ... Injector, 8 ... Electric fan, 83 ... Relay (electric fan drive means), 9 ... Control unit (control means), 14 ... Water temperature switch (temperature detection means).

Claims (1)

[Scope of utility model registration request] 1. An engine provided with an electric fan, a temperature detecting means for detecting a temperature related to an engine temperature, and an electric fan driving means for driving the electric fan when the temperature detected by the temperature detecting means is equal to or higher than a predetermined value. In the fuel control device, based on the operating time detecting means for detecting a parameter related to the operating time of the electric fan, and the parameter detected by the operating time detecting means, when the operating time is equal to or longer than the set time, A fuel control device for an engine, comprising: a control means for increasing a fuel supply amount.