JPS6036746A - Overheat preventing increase of amount of catalyst for electronic-controlled engine - Google Patents

Abstract

PURPOSE:To improve the blow-up of the engine upon racing by a method wherein an output increase of amount of catalyst is effected upon engine racing so as to obtain an output air-fuel ratio and the overheat preventing increase of amount of catalyst is effected in case the engine is not racing when the operating condition of the engine is in catalyst overheating zone. CONSTITUTION:An electronic control unit 54 decides from the opening degree of a throttle, detected by a sensor 22, and the amount of suction air, detected by a flow meter 14, whether the operating condition of the engine is in the overheating zone of the catalyst 41 or not. When it is decided that the operating condition is in the overheating zone, it is decided by the change of revolving number of engine, detected by the sensor 46, whether it is in the engine racing or not. When the change is small and it is decided that the engine is not in racing, a normal increasing value of amount of catalyst for preventing overheat of catalyst in accordance with the operating condition is entered into the increasing value for preventing the overheat of the catalyst, which is added to a basic injection amount, to bring the air-fuel ratio into rich side. On the other hand, when it is decided that the engine is in the racing, the value of output increasing amount is entered so as to obtain the air-fuel ratio of about 13-12. According to this method, the blow-up of the engine may be improved without affecting the deterioration of the catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for increasing the amount of catalyst for preventing overheating in an electronic 11i11111 engine, and in particular, it is suitable for use in an automobile engine equipped with an electronically controlled fuel injection device, and is suitable for at least engine load and engine rotation. With respect to the basic fuel consumption of $131, which is determined according to the speed, when the engine operating state is in the catalyst over-PA range, the amount of catalyst overheating prevention is increased so that the air-fuel ratio is on the rich side to prevent catalyst overheating. The present invention relates to an improvement in a method for increasing the amount of catalyst to prevent overheating of an electronic sterilization engine.

One of the methods of supplying a mixture with a predetermined air-fuel ratio to the combustion chamber of an internal combustion engine such as an automatic single-purpose engine is the so-called electronic control Ml.
Some use a fuel cracker. This is achieved by disposing injectors for injecting fuel into the engine, for example, in several engine cylinders in the intake manifold of the engine, and by controlling the valve opening time of the injectors according to the operating state of the engine. This is to ensure that the air-fuel mixture with the correct fuel ratio is supplied to the engine combustion chamber.

In this electronically controlled fuel injection tkJ device, the basic injection amount is determined according to the engine load and engine speed detected from the intake air amount or intake pipe pressure, and the engine operating state is determined for this basic injection device, for example. When the catalyst is in the overheating range detected by the throttle opening and intake air amount, the catalyst is overheated and the amount of prevention is increased so that the air-fuel ratio is on the rich side to prevent catalyst overheating.

However, in the past, the amount of catalyst overheat prevention was increased solely for the purpose of reducing catalyst temperature, and no consideration was given to engine output performance. Therefore, even if the catalyst enters the overheating range for a short time, such as during engine racing, if the throttle opening or intake air amount enters the catalyst overheating range, the amount of catalyst overheating will be increased. In high rotation and high load ranges, the air-fuel ratio becomes richer than the output air-fuel ratio, resulting in a problem of poor engine racing. Such problems are particularly noticeable in engines that tend to run at high speeds and have high outputs, where it is necessary to significantly enrich the air-fuel ratio in order to prevent catalyst overheating at high speeds.

The present invention has been made in order to solve the above-mentioned conventional problems, and is a method for increasing the amount of a catalyst to prevent overheating in an electronically controlled engine, which can improve the revving during engine racing without significantly affecting the deterioration of the catalyst. The purpose is to provide.

The present invention increases the amount of catalyst overheat prevention so that the air-fuel ratio becomes rich when the engine operating state is in the catalyst overheating range, at least with respect to the basic fuel amount determined according to the engine load and engine rotation speed. Fig. 1 shows the weaknesses of the method for increasing the amount of catalyst overheating in an electronically controlled engine, which prevents catalyst overheating by performing the following steps: and, when the catalyst is in the overheating range, a procedure for determining whether or not it is engine racing, and when it is engine racing, a procedure for increasing the output so that the air-fuel ratio becomes the output horn air-fuel ratio,
The above object is achieved by including the step of increasing the amount of the catalyst to prevent overheating.

In the present invention, even if the engine operating state is in the catalyst overheating range, if the engine is racing 3, the amount of catalyst overheating prevention is not increased.
Since the output is increased, the output air-fuel ratio can be obtained during engine racing. Therefore, over-riching of the air-fuel ratio during engine racing is prevented, and the engine speed is improved. Furthermore, engine racing is usually for a short period of time and the number of times it is used is smaller than in full-use TR darkness, so there is little risk of it having a major effect on catalyst deterioration.

Below, with reference to the drawings, an embodiment of an electronically controlled automobile engine equipped with an electronically controlled fuel injection device that senses the amount of intake air, in which the method for increasing the amount of catalyst overheating in an electronically controlled engine according to the present invention is adopted, will be explained in detail with reference to the drawings. Explanation

As shown in FIG. 2, this embodiment includes an air flow meter 14 for detecting the flow rate of the intake air taken in by the air cleaner 12, and an air flow meter 14 built in the air flow meter 14 for detecting the temperature of the intake air. It rotates in conjunction with the intake air temperature sensor 16 and the accelerator pedal 18, and
A throttle sensor 22 that detects the opening degree of the throttle valve 20 and an intake manifold 26 that distributes intake air flowing in through a surge tank 24 to each cylinder are provided.
A fuel tank 30. An injector 2B for intermittently injecting pressurized fuel supplied via the fuel pump 32 and fuel piping 34, and an engine combustion engine. The lζth oxygen concentration sensor detects the air-fuel ratio from the oxygen concentration in the exhaust gas, and is installed in the exhaust manifold 38 that collects the exhaust gas of the air-fuel mixture sucked into the engine and ignited and combusted by the spark plug 36. (hereinafter referred to as the 02 sensor) 40, the catalytic converter 41, and the catalytic converter 41, and a destripulator shaft 44A built in the destripulator 44 for distributing the high voltage secondary ignition signal generated by the ignition coil 42 to the spark plugs 36 of each cylinder.
a rotational speed sensor 46 for detecting the rotational speed and crank angle of the engine 10 from the rotational state of the engine, a water temperature sensor 48 for detecting the engine cooling water temperature disposed in the cylinder block IOB of the engine 10, and a battery 52. For example, the basic injection amount is determined according to the intake air amount determined from the air 70-meter 14 output and the engine rotation speed determined by the rotation speed rotation speed sensor 46 output, and this is calculated from the output of the throttle sensor 22 and the 02 sensor. 40
An electronic control unit (hereinafter referred to as ECU) determines the effective cleavage by correcting the increase or decrease according to the output, water temperature sensor 48 output, etc., and outputs a valve opening time signal to the injector 28 so that the effective injection amount can be obtained. It is composed of 54 and 54.

As shown in detail in FIG. 3, the ECLI 54 includes a central processing unit (hereinafter referred to as CPLI) 54A consisting of, for example, a microprocessor for performing various arithmetic operations, and a control program and various data stored in advance. A read-only memory (hereinafter referred to as ROM) 54B, a random access memory (hereinafter referred to as RAM) 54C for temporarily storing calculation data etc. in the CPU 54A, the output of the intake temperature sensor 16, and the water temperature sensor 48. Analog signals such as output are sequentially converted into digital 16
An analog-to-digital converter (hereinafter referred to as an A/D converter) 54E having a multiplexer function for converting and importing the signals into signals, and an analog-to-digital converter (hereinafter referred to as an A/D converter) 54E, and according to the output of the first afrometer 14 and the output of the rotation speed sensor 46, A basic pulse generation circuit 54F for generating a basic pulse with a pulse width corresponding to the basic odor @ value, the output of the basic pulse generation circuit 54F, the output of the throttle sensor 22, and the 02 sensor 40.
In addition to taking in a digital converter such as an output, the CPtJ
The injector 28 and the ignition coil 42 are controlled according to the calculation results of the injector 28 and the ignition coil 42 according to the calculation results of the input/output port (hereinafter referred to as I10 port) 54G for outputting the l signal, and a common bus 54H that connects each of the component devices. has been done.

The action will be explained below.

In this embodiment, the catalyst overheat prevention amount increase when the engine operating state is in the catalyst overheat region is executed according to the flowchart shown in FIG. That is, first, in step 110, the throttle opening degree T'H determined from the output of the throttle sensor 22 and the intake air amount Qa determined from the output of the air flow meter 14 shown in IiI'I are taken. Next, the process proceeds to step 112, where, for example, the throttle opening degree TH or the intake air taken in in step 110 is determined! Since lQa is larger than the determination value, it is determined whether or not the engine operating state is in the catalyst overmaturity region. If the determination result is positive, the process proceeds to step 114, where the engine rotational speed 1iN determined from the output of the rotational speed sensor 46 is determined.
take in. Next, the process proceeds to step 116, where the amount of change ΔN in the engine rotational speed is calculated by subtracting the current engine rotational speed N1 from the previous engine rotational speed Ntl, for example, as shown in the following equation.

Δ N 1 ←N+-+ Nl ・・・ ・・・・・・
(1) Next, the process proceeds to step 118, where a substitute characteristic value ΔNol indicating the change in engine rotation is calculated from the previously calculated value ΔI'J or r−+ and the engine rotation speed change amount ΔN1 calculated this time, as shown in the following equation. Calculate.

8Nol←(8N o +−＋＋ΔN+)/2−・
----(2) Next, the process proceeds to step 120, and it is determined whether the substitute characteristic value 8-ΔNot indicating the change in engine rotation calculated in step 11B is greater than the determination value Δ. If the determination result is negative, that is, if the change in engine rotation is small and it is determined that the engine is not racing,
Proceeding to step 122, enter the normal catalyst overheat prevention increase value according to the engine operating condition into the catalyst overheat prevention increase value FOT added to the basic injection amount, and set the air-fuel ratio to the rich side, for example, about A/F 14 to 10. The normal increase in catalyst overheat prevention should be carried out so that Therefore, in this case, catalyst overheating is reliably prevented.

On the other hand, if the determination result in step 120 is positive,
That is, when the engine speed change is large and it is determined that engine racing is in progress, the process proceeds to step 124;
The catalyst overheat prevention 11 quantity value FOT indicates that the air-fuel ratio is 13 at A/F.
Approximately 14~, which results in an output air-fuel ratio of ~12.
Input an output increase value of about 22%. Therefore, in this case, the output is increased, and the engine revving is improved.

On the other hand, if the determination result in step 112 is negative,
That is, when it is determined that the catalyst is not in the overheating range, the process proceeds to step 126, and zero is set in the catalyst overheating prevention increase 1st shift, so that the catalyst overheating prevention increase is not performed.

An example of how the engine speed and air-fuel ratio change during engine racing in this embodiment is shown by the broken line B in FIG. It is clear that there is no over-richness and the engine revs up well.

In this embodiment, the determination as to whether or not engine racing is in progress is made by using a substitute characteristic value indicating a change in engine rotation.
Since the determination J is made based on whether or not i becomes larger than the determination value A, the engine racing can be determined relatively easily and accurately. Note that the method for determining engine racing is not limited to this.

In the above embodiment, the present invention was applied to an electronically controlled automobile engine equipped with an electronically controlled fuel injection device that senses the amount of intake air, but the scope of application of the present invention is not limited thereto. It is obvious that the present invention can be similarly applied to an electronically controlled automobile engine equipped with an electronically controlled fuel injection device of the intake pipe pressure sensing type, and a general electronically controlled 11 engine equipped with an electronically controlled carburetor.

As explained above, according to the present invention, during engine racing, over-riching of the air-fuel ratio is prevented even in the catalyst overheating region, and an output air-fuel ratio can be obtained. Therefore, good engine speed can be obtained during engine racing. Moreover, since the engine racing is for a short time, it has the excellent effect of not having a large effect on the deterioration of the catalyst.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the gist of the method for increasing catalyst overheating prevention for an electronically controlled engine according to the present invention, and FIG. Showing the configuration of an example of an electronically controlled automobile engine,
3 is a cross-sectional view including a partial block diagram, FIG. 3 is a block diagram showing the configuration of the electronic control unit used in the above embodiment, and FIG. FIG. 5, a flowchart showing the routine, is a diagram comparing and showing examples of changes in the air-fuel ratio and engine rotational speed during engine racing in the embodiment and the conventional example. 10... Engine, 14... Air flow meter,
22...Throttle sensor, 28...Injector, 41...Catalytic converter, 46...Rotational speed sensor, 54...Electronic control unit (ECU>. Agent Takaya Ron (and 1 other person) - '1 N-Kushin)-1,) Time layer Tsufusuma. Fig. 3 54 54A 16 CPU A/D 4E 4B OM 4F 14 Komushimata 54G 54H54C46'1 2RAM 10 8 +7 "-1111-" Fig. 4 1 342-

Claims (1)

[Claims] (1) When the engine operating condition is in the catalyst overheating range, increase the amount of catalyst overheat prevention so that the air-fuel ratio is on the rich side, at least with respect to the basic fuel amount determined according to the engine load and engine speed. In the method for increasing the amount of catalyst overheating in an electronically controlled engine to prevent catalyst overheating, there is a procedure for detecting that the engine operating state is in the catalyst overheating range, and a procedure for detecting when the catalyst is in the overheating range during engine racing. The procedure for determining whether or not there is a
A method for increasing the amount of catalyst for preventing overheating in an electronically controlled engine, the method comprising: increasing the amount of catalyst for preventing overheating.