JPH04203252A - Device detecting and treating accidental fire in internal combustion engine for vehicle - Google Patents

Abstract

PURPOSE:To prevent an accidental fire from being erroneously detected by detecting the condition of a vehicle to judge whether or not the present condition of the vehicle is liable to be erroneously detected an accidental fire and, if judged YES, annulling substantially the detecting result of an accidental fire detecting means to stop detecting and treating the accidental fire. CONSTITUTION:A rotational speed variation obtained from instantaneous rotational speed is compared with an accidental fire value obtained from requirements of an internal combustion engine. An accidental fire detecting means A for judging the accidental fire when the variation of the rotational speed is larger than an accidental fire judging value is provided so that the accidental fire detected is treated by an accidental fire treating means B. Thus, further a vehicle condition detecting means C for detecting the condition of the vehicle is provided so that it is judged by a judging means D whether or not the vehicle is in the condition having an effect on the detection of accidental fire by the accidental fire detecting means A according to the detecting output of the means C. When the vehicle is judged by the judging means to be under the condition having an effect on the accidental fire detection, the detecting result of the accidental fire detecting means A is substantially annulled by an accidental fire detection annulling means E.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a misfire detection processing device for a vehicle internal combustion engine that detects a misfire in a vehicle internal combustion engine and executes a misfire detection process when a misfire occurs.

[Prior art J] Conventionally, misfire in an internal combustion engine is detected by detecting the instantaneous rotational speed of the internal combustion engine at at least two points within one ignition cycle, determining the amount of rotational speed fluctuation from this instantaneous rotational speed, and detecting the internal combustion engine in the event of a misfire. Since the engine rotational speed decreases, the amount of variation in the internal combustion engine's rotational speed is compared with the misfire judgment value determined from the internal combustion engine conditions, and a misfire is determined when the amount of variation in the rotational speed is greater than the misfire judgment value. (For example, JP-A-58-
51, 243).

[Problem to be solved by the invention]

However, depending on the state of the vehicle, the amount of variation in the rotational speed of the internal combustion engine may become large at times other than when a misfire occurs, and in this case, a problem arises in that a misfire is erroneously detected.

The misfire detection and stop device of the present invention has been made to solve the above-mentioned problems, and even if a misfire is detected in a vehicle state where misfire is easily detected erroneously, this detection result is invalidated. The purpose is to promote effective misfire handling by not performing misfire handling such as stopping the fuel supply to the engine.

(Means for Solving the Problems) In order to achieve the object stated in -1-, the misfire detection and stop device according to the present invention, as shown in FIG. misfire processing means that executes misfire processing when the detection means detects a misfire; vehicle state detection means that detects the state of the vehicle; a discriminating means for discriminating whether or not a vehicle condition affects the misfire detection; and a misfire detection for substantially invalidating the detection result of the misfire detecting means when the discriminating means determines that the vehicle condition affects the misfire detection. Adopt technical means of providing invalid means.

[Operation] According to the present invention, the vehicle state is detected by the vehicle state detection means, and based on the detection result, it is determined whether or not the current vehicle state is such that it is easy to misdetect a misfire. If it is determined that the vehicle is in a state where it is easy to mistakenly detect a misfire, the detection result of the misfire detection means is substantially invalidated and the misfire detection process is not executed.

〔Example〕

Hereinafter, the present invention will be explained based on embodiments shown in the drawings.

FIG. 2 is a block diagram of a misfire detection processing device for a vehicle internal combustion engine in this embodiment.

In FIG. 2, 1 is a rotation angle sensor attached to the crankshaft or camshaft of an internal combustion engine (not shown) and detects the rotation speed and crank position of the internal combustion engine, and 2 is an intake in the intake manifold of the internal combustion engine (not shown). These are intake air pressure sensors that detect air pressure, and detection signals from these sensors are input to an internal combustion engine microcomputer 8, which will be described later.

3 is a vehicle speed sensor that is attached to the vehicle's transmission etc. and detects the vehicle speed; 4 is located in the fuel tank;
A fuel detection device detects the remaining amount of fuel, 5 is a brake switch that detects whether the driver has stepped on the brake or pulled the brake, and 6 is a water temperature sensor that detects the temperature of the cooling water of the internal combustion engine. , the state of the vehicle is detected by each of these sensors, and the detection signal from each sensor is input to the electronic meter computer 7.

Reference numeral 7 denotes an electronic meter microcomputer (hereinafter referred to as "electronic meter microcomputer") which calculates according to the above-mentioned detection signal and the output from the signal from the ignition device 9, which will be described later, and outputs a signal for accurately operating the electronic meter ↑2. (referred to as meter ECU)
It is. Further, the meter ECU 3 has a discriminating means for recognizing the vehicle condition and discriminating whether it affects misfire detection, and a misfire detection disabling means for disabling the misfire detection result according to the discrimination result. The determination result as to whether or not to invalidate the result is input to the internal combustion engine microcomputer 8 by one determination result signal 7a.

Reference numeral 8 denotes an internal combustion engine microcomputer (hereinafter referred to as internal combustion engine ECU) that performs arithmetic processing to control the fuel system and ignition system of the internal combustion engine, and includes an ignition device 10, which will be described later.
A signal for optimal control of the injector 11 is output. Further, the internal combustion engine ECU 6 executes misfire determination based on the signals from each of the above-mentioned sensors, and when it is determined that a misfire has occurred, the internal combustion engine ECU 6 includes a misfire processing means such as a diagnostic display device 9 that lights up to warn the vehicle user when a misfire occurs. Outputs a signal to control the device.

Reference numeral 10 denotes an ignition device that generates high voltage at optimal ignition timing based on a signal from the internal combustion engine ECU 8 and supplies the high voltage to the ignition plug of the internal combustion engine. Further, a signal for detecting the rotational speed of the internal combustion engine is input from an ignition coil (not shown) in the ignition device 10 to the meter ECU 7. Reference numeral 11 denotes an injector that supplies fuel to the internal combustion engine at an optimal fuel injection amount based on a signal from the internal combustion engine ECU 3.

FIG. 3 is a flowchart showing the operation of the meter ECU 3, and this routine is executed at predetermined time intervals.

In FIG. 3, in step 100, signals from each sensor shown in FIG. 2 are read, and in step 110, based on the signals read in step 100, the electronic meter
Perform calculations to accurately display 2. Step 120
Step ], ] From the calculation result at 0, it is determined whether the remaining amount of fuel is greater than a predetermined value (for example, 2ff), and if it is less than the predetermined value, rotational fluctuations of the internal combustion engine due to lack of fuel are detected. In order to avoid erroneous misfire determination due to the increase in the amount, the process proceeds to step 160. On the other hand, if it is greater than or equal to the predetermined value, the process proceeds to step 130. In step 130, it is determined whether the brake switch is on or off, and if it is on, the process proceeds to step 160 in order to avoid erroneous misfire determination due to an increase in the rotational fluctuation amount of the internal combustion engine due to sudden braking, for example. Also,
If the brake switch is off, proceed to step 140. In step 140, it is determined whether the vehicle speed is less than a predetermined value (for example, 1.60 km/h), and if the vehicle speed is greater than or equal to the predetermined value, the vehicle is traveling at high speed, and for example, the vehicle is traveling on a rough road. When this happens, there is a risk that a very large impact will be transmitted to the internal combustion engine and the amount of rotational fluctuation will increase, so the process proceeds to step 1.60 in order to avoid erroneous misfire detection. On the other hand, if the speed of the vehicle is below the predetermined value, the process proceeds to step 150.

In step 150, it is determined that the vehicle condition is such that misfire detection can be performed in the "-" determination, and the vehicle condition flag
Set MF to 1. In step 1.60, it is determined that the vehicle condition is not in a state where a misfire is detected, and the vehicle condition flag XMF is set.
Set to O.

FIG. 4 is a flowchart showing the misfire detection operation in the internal combustion engine ECU 6, and this process is executed at every predetermined rotation angle according to the rotation angle sensor 1.

In FIG. 4, at step 200, the vehicle status flag XMF shown in FIG. 3 is read. In step 210, it is determined whether the vehicle status flag XMF is 1 or not, and if it is not 1, this routine is ended.

On the other hand, if the value is 1, the process proceeds to step 220, where a misfire detection process is executed. Incidentally, misfire detection is performed by calculating the amount of rotational fluctuation of the internal combustion engine, which is already known, and using this amount of rotational fluctuation as a predetermined amount set from the detection signals from the rotational angle sensor 1 and the intake air pressure sensor 2 shown in FIG. By comparison, if the amount of rotational fluctuation is less than a predetermined value, it is determined that a misfire has occurred (for example, Japanese Patent Application Laid-Open No. 61-258955).

In the next step 230, the results of misfire detection performed in step 220 are read, and it is determined whether or not a misfire has been detected. If it is determined that a misfire has been detected, step 230 is performed.
The process proceeds to 40, and in step 240, the indicator light of the diagnostic display device 9 is turned on to inform the vehicle user of an abnormality in the vehicle, and in step 250, the fuel supply to the cylinder in which the misfire has been detected is stopped, thereby protecting the catalyst and Prevent growth.

Further, if no misfire is detected in step 230, the routine returns.

In this embodiment, since the vehicle state is recognized by the meter ECU 3, there is no need to provide a new sensor for detecting the vehicle state, so the present embodiment can be implemented with a simple configuration and can be put into practical use at low cost.

In this embodiment, the misfire detection process was executed only when the vehicle status flag was 1, but as shown in FIG. Misfire diagnosis processing such as turning on the diagnosis display device 9 or stopping the fuel supply to the cylinder in which the misfire has occurred may be executed. Note that in FIG. 5, the same reference numerals as in FIG. 4 indicate that the same processing as in FIG. 4 is executed.

Furthermore, in the above embodiment, the meter ECU 7 determines whether or not the vehicle is in a state where misfire detection is to be performed, but the detection signals from each sensor are directly transmitted to the internal combustion engine ECU 7.
8, the internal combustion engine EC1J 8 may determine whether the vehicle is in a vehicle state in which misfire detection is to be performed.

[Effects of the Invention] As described above, the present invention effectively prevents misfires by invalidating the misfire detection result and not executing misfire processing in vehicle conditions where a misfire is easily detected in accordance with the driving state of the vehicle. This has the effect of allowing processing to be carried out.

[Brief explanation of the drawing]

FIG. 1 is a diagram corresponding to the claims of the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, FIG. 3 is a flowchart showing the operation of vehicle state detection of the present invention, and FIGS. 3 is a flowchart showing an operation for executing misfire detection according to the invention. 3...Vehicle speed sensor, 4...Remaining fuel level detection device,
- Brake switch 17... Microcomputer for electronic meter, 8... Microcomputer for internal combustion engine, 9... Diagnostic display device. Representative Patent Attorney Takashi Okabe (and 1 other person) Figure 3 Figure 4

Claims (3)

[Claims] (1) misfire detection means for detecting a misfire in a vehicle internal combustion engine; misfire processing means for executing misfire processing when the misfire detection means detects a misfire; vehicle state detection means for detecting the state of a vehicle; a determining means for determining whether or not the vehicle condition affects the detection of a misfire by the misfire detecting means, according to a detection output of the condition detecting means; A misfire detection and processing device for an internal combustion engine for a vehicle, comprising misfire detection invalidating means for substantially invalidating the detection result of the misfire detecting means. (2) The vehicle state detection means detects that the remaining fuel level of the vehicle is below a predetermined value, that the vehicle speed is above a predetermined value, and that the vehicle is in a braking state. The misfire detection processing device for a vehicle internal combustion engine according to claim 1, wherein the misfire detection processing device for a vehicle internal combustion engine is at least one of the devices for detecting. (3) The vehicle includes an electronic meter and an electronic meter control device for controlling the electronic meter, and the determining means is provided in the electronic meter control device. 2. The misfire detection processing device for a vehicle internal combustion engine according to item 2.