JPS626172A - Abnormality detecting device for vehicle speed detecting means - Google Patents

Abstract

PURPOSE:To detect an abnormality in an early stage by deciding a vehicle speed detecting means to be abnormal, if the output of the vehicle speed detecting means is zero, when the outputs of an inlet pipe pressure deciding means, an engine rotating speed deciding means and an engine temperature deciding means are obtained. CONSTITUTION:A vehicle M5 whose driving source is an internal combustion engine M1 is provided with a means (M2, M7) for detecting a suction pressure of the internal combustion engine M1 and deciding a fact that is exceeds a prescribed value, means (M3, M8) for detecting a rotating speed and deciding a fact that it exceeds a prescribed value, and a means (M4, M9) for detecting a temperature and deciding a fact that it exceeds a prescribed value. To the pressure deciding means M7 among them, a correcting means M11 for correcting a prescribed pressure by the output of the rotating speed detecting means M3 is connected in advance. In this way, when the output of a vehicle speed detecting means M6 is zero in a state that the outputs of these means M7-M9 are obtained (namely, in a state that the vehicle speed is not zero), it is decided by a deciding means M12 that the means M6 is abnormal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for detecting an abnormality due to a failure or the like of a vehicle speed detecting means of a vehicle whose driving power source is an internal combustion engine.

[Prior Art] In recent years, electronic control devices have been used to precisely control internal combustion engines in automobiles and the like, and progress has been made to improve output, fuel efficiency, emissions, drivability, etc.

This control can be realized for the first time by detecting the state of the internal combustion engine and the vehicle using various sensors and using the data. For example, a throttle opening sensor detects the fully open state of the throttle valve, and a vehicle speed sensor consisting of a magnet, reed switch, or magnetically sensitive element that rotates with the rotation of the speedometer cable, or optically detects the rotation of the speedometer cable. A vehicle speed sensor is used to detect whether or not the vehicle is stopped, thereby detecting the idle state of the engine, and controlling the engine rotational speed and air-fuel ratio during idling. However, if a failure occurs in which the vehicle speed sensor no longer outputs a signal due to a malfunction in the magnet, a defect in the reed switch, or a break in the signal line connecting the vehicle speed sensor and the control circuit, the throttle valve may be closed to decelerate. Since it is determined that the vehicle is stopped based on the vehicle speed sensor output, the engine speed and air-fuel ratio during deceleration are controlled to the values during idling, resulting in inappropriate operation.

Conventionally, the following abnormalities have been detected.

That is, even if the intake pipe pressure, engine speed, and engine cooling water temperature of the internal combustion engine are each higher than a predetermined value, if the detected value of the vehicle speed detection means (vehicle speed sensor) is zero, it is determined that the vehicle speed detection means is abnormal. , was intended to measure the response.

This usually defines a driving range that does not occur when the vehicle speed is zero, and each predetermined value must have a sufficient gap from the normal value to prevent false detection. did not become. For example, the pressure in the intake pipe had to be set to a high value that would never occur in racing, and the engine speed had to be set to a value higher than the number of revolutions that would cause a stall.

[Problems to be Solved by the Invention] Considering the above conditions, the range in which it is actually possible to detect an abnormality in the vehicle speed detection means is approximately 60 km/hr or more when the top gear is shifted, and about 60 km/hr or more when the gear shift is in the second gear. Approximately 40km
/hr or more. This is a vehicle speed that is difficult to achieve when driving on a general road, and as a result, the discovery of an abnormality in the vehicle speed detection means is delayed.

As a result, fuel efficiency, output, and emissions may be adversely affected due to improper engine operation, and automatic transmissions may continue undetected for long periods of time without being able to properly control gear shifts.

SUMMARY OF THE INVENTION Therefore, the present invention provides an abnormality detection device for vehicle speed detection means that increases the chances of detecting an abnormality in vehicle speed detection means and allows countermeasures to be taken at an early stage.

[Means for Solving the Problems] The present invention employs the following configuration as a means for solving the above problems.

That is, the gist of the present invention is, as shown in FIG. 1, that an internal combustion engine M1 is used as a driving force source, and that at least an intake pipe pressure detecting means M2 of the engine M1, a rotation speed detecting means M3 of the engine M1, , an abnormality detection device for a vehicle speed detection means M6 provided in a vehicle M5 having a temperature detection means M4 of the engine M1, detects whether the intake pipe pressure detected by the intake pipe pressure detection means M2 is equal to or higher than a predetermined pressure. pressure determining means M7 for determining; and rotation speed determining means M for determining whether the rotation speed detected by the rotation speed detection means M3 is equal to or higher than a predetermined rotation speed.
8, humidity determining means M9 for determining whether the temperature detected by the temperature detecting means M4 is equal to or higher than a predetermined temperature, and vehicle speed determining means M10 for determining whether the vehicle speed detected by the vehicle speed detecting means M6 is zero. and the pressure determining means M
The predetermined pressure used in step 7 is applied to the rotational speed detection means M3.
A correction means M that corrects according to the rotational speed detected by
11, the pressure determining means M7, and the rotational speed determining means M8.
, a determining means M12 for determining that the vehicle speed detecting means M6 is abnormal when the determinations in the temperature determining means M9 and the vehicle speed determining means MIO are simultaneously satisfied. It's in the device.

The vehicle speed detection means M6 outputs a zero vehicle speed when a reed switch or a magnetically sensitive element outputs an on/off signal using a rotating magnet or the like is disconnected or stops rotating.

[Operation] The pressure determining means M7 determines that the intake pipe pressure of the engine M1 is equal to or higher than a predetermined pressure, the rotational speed determining means M8 determines that the rotational speed of the engine M1 is equal to or higher than a predetermined speed, and the temperature determining means M9 determines that the rotational speed of the engine M1 is equal to or higher than a predetermined speed. If it is determined that the engine temperature is higher than a predetermined temperature, the vehicle speed is usually not zero, and this cannot occur unless the vehicle is running.

Therefore, when the vehicle speed determining means M10 simultaneously determines that the vehicle speed is zero, the determining means M12 determines that the vehicle speed detecting means M6 is abnormal. If it is determined that the vehicle speed detection means M6 is abnormal in this way, corresponding processing is performed by other control means.

Each of the above determination means M7. M8. The predetermined values for determination of M9 are set based on experiments and the like, so that when all detected values are equal to or higher than the predetermined values, the actual vehicle speed becomes zero, which is 1q less. However, the predetermined pressure in the pressure determining means M7 is
In order to detect an abnormality in the vehicle speed detection means M6 with a value as low as possible, the correction means M11
Correction is made according to the engine rotation speed. This increases the chances of discovering an abnormality in the vehicle speed detection means M6.

Next, embodiments of the present invention will be described based on the drawings.

The present invention is not limited thereto, and may be implemented in various forms without departing from the scope of the invention.

[Example] FIG. 2 shows a configuration diagram of an embodiment of the present invention.

Here, 1 is the internal combustion engine body, 2 is the piston, 3 is the spark plug, 4 is the exhaust pipe, 6 is the fuel injection valve that injects fuel into the intake air of the internal combustion engine body 1, 7 is the intake pipe, and 9 is the internal combustion engine A water/temperature sensor that detects the temperature of the cooling water; 10 a throttle valve; 11 a throttle opening sensor that is linked to the throttle valve 10 and detects the opening of the throttle valve 10 and outputs a signal; 14 a Sonage tank 15; Each figure represents an intake pressure sensor that measures intake pipe pressure.

A distributor 17 is connected to a crankshaft (not shown) and distributes the high voltage generated by the igniter to the spark plugs 3 of each cylinder; Rotation angle sensor equipped with a rotation speed detection means that outputs 24 pulse signals for 2 rotations of the shaft, 19
2 is a cylinder discrimination sensor that outputs one pulse signal per revolution of the distributor 17; 20 is an electronic control circuit; 21
is a diagnosis control circuit having a vehicle speed sensor abnormality warning lamp 22, and 23 is a near conditioner switch (
air conditioner switch). A vehicle speed sensor 24 serves as a vehicle speed detection means for detecting the rotational speed of the output shaft of the automatic transmission 26, and is turned on in response to changes in the magnetic force of a rotating magnet 2=18 directly connected to the output shaft of the automatic transmission 26. - Consists of a reed switch 24b that outputs an off signal.

Next, in the electronic control circuit 20, a central processing unit (hereinafter simply referred to as CPU) 30 inputs and calculates data output from each sensor according to a control program, and performs processing for controlling the operation of various devices.
31 is a read-only memory (hereinafter simply referred to as ROM) in which the control program and initial data are stored;
32 is a random access memory (hereinafter simply referred to as RAM) in which data input to the electronic control circuit 20 and data necessary for arithmetic control are temporarily read and written; 33 is a memory that is used to operate the internal combustion engine after the key switch is turned off; A backup random access memory (hereinafter simply referred to as backup RAM) 36 is a non-volatile memory backed up by a battery to hold the data necessary for the process, and 36 receives signals from various sensors and processes waveform shaping and processing as necessary. An input port where A/D conversion is performed; 38 is an output port where signals for controlling and driving the fuel injection valve 6, lighting circuit 21, etc. are output; 39 is data and address information between each element of the electronic control circuit 20. It represents a path line 39 that transmits.

Next, a processing program executed by the electronic control circuit 20 will be explained. FIG. 3 is a flowchart showing the processing contents. This process is repeatedly executed at regular intervals. This electronic control circuit 20 also executes other processes such as fuel injection amount control and ignition timing control.

First, when the process is started, step 110 is executed, where the engine 1 cooling water temperature (TI-(W>) is the signal from the water temperature sensor 9, and the engine rotation speed (NE> is the rotation angle sensor 1).
8, the intake pipe pressure (Pi) is determined by the signal from the intake pressure sensor 14, and the vehicle speed (Sp) is determined by the signal from the vehicle speed sensor 2.
The data is read into the RAM 32 by a signal from 4.

Next, in step 120, the vehicle speed (Sp) is zero (km/h).
r) is determined. If it is not zero, it is determined as rNOJ, and the process is temporarily terminated. That is, if it is not zero, there is no abnormality in the vehicle speed sensor 24. Step 12
If rYEsJ is determined in step 130, it is determined in step 130 whether or not the cooling water temperature (T l−I W > is equal to or higher than a predetermined temperature T).

If it is less than 1, this is not a condition for determining an abnormality of the vehicle speed sensor 24, so it is determined that rNOJ is present, and the process is temporarily terminated. When rYEsJ is determined in step 130, it is then determined in step 140 whether or not the engine rotational speed NE is equal to or higher than a predetermined rotational speed N. If it is less than N, this is not a condition for determining an abnormality of the vehicle speed sensor 24, so it is determined as rNOJ, and the process is temporarily terminated. Step 140
If rYEsJ is determined in step 150, it is determined from the output of the air conditioner switch 23 whether or not the near conditioner (A/C) is on.

If the air conditioner switch 23 is on, it is determined as rYEsJ, and step 160 is executed. On the other hand, if the air conditioner switch 23 is off, it is determined as rNOJ, and step 170 is executed.

The process of step 160 is to search and determine the predetermined pressure P for determination from the engine speed NE using the map corresponding to the solid line graph a of the graphs shown in FIG. On the other hand, the process of step 170 is to search and determine P from NE using the map corresponding to graph b indicated by a dashed-dotted line among the graphs shown in FIG.

Here, a is set at a higher pressure level than b. This is because when the near conditioner is working at zero vehicle speed, such as when idling or racing, the value of intake pipe pressure is high. The intake pipe pressure that can actually be obtained during racing is measured when the air conditioner is turned on.
Ic, two-point chain I when off! Indicated by d.

Next, in step 180, it is determined whether the output j value of the intake pressure sensor 14 is equal to or higher than a predetermined pressure P. If it is less than 2,
Since it is not an abnormality determination condition for the vehicle speed sensor 24, rNOJ
It is determined that this is the case, and the process is temporarily terminated. Step 18
If rYEsJ is determined at 0, then step 190
is executed.

In this state, steps 120, 130, 140 .
Since each condition 180 is satisfied, it can be determined that the vehicle speed sensor 24 is abnormal, but to ensure accuracy, it is determined in step 190 whether 5 seconds have elapsed. This 5
If the conditions at steps 120, 130, 140, and 180 are not satisfied for a second, the vehicle speed sensor 24 is not determined to be abnormal.

If it is determined in step 190 that 5 seconds have elapsed, then in step 200 a code signal indicating that the vehicle speed sensor 24 is abnormal is output to the diagnosis control circuit 21. As a result, the diagnosis control circuit 21 turns on the vehicle speed sensor abnormality warning lamp in accordance with the code signal.

Next, in step 210, a flag Ff indicating an abnormality in the vehicle speed sensor 24 is set. As a result, in other processes, such as automatic transmission control and internal combustion engine control, the flag Ff is checked to prevent an adverse effect.

Among the above-mentioned steps, step 120 is a process as a vehicle speed determination means, step 130 is a process as a temperature determination means, step 140 is a process as a rotational speed determination means, steps 150, 160 and 170 are processes as a correction means, Step 180 corresponds to processing as a pressure determining means.

As described above, in this embodiment, since the predetermined pressure P for determining the intake pipe pressure Pi is corrected according to the engine speed NE, as shown in FIG. A predetermined pressure Pe can be set along the line. Therefore, it is not necessary to set a high level ifi as shown by the solid line e in order to cover all the racing areas as in the conventional case. As a result, the chances of discovering an abnormality in the vehicle speed sensor 24 increase. Furthermore, since two types of maps are used to match the load of the near conditioner, the chances of detecting an abnormality are not reduced even in a vehicle equipped with a near conditioner.

In the above embodiment, the system waits for 5 seconds in step 190 to ensure accurate abnormality detection, but abnormality detection can be performed without any special provision.

[Effects of the Invention] In the present invention, when detecting an abnormality in the vehicle speed detection means, the predetermined pressure for determining the intake pipe pressure is corrected in accordance with the engine rotation speed. Therefore, the chances of discovering an abnormality in the vehicle speed detection means are further increased, and countermeasures can be taken at an early stage.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of the present invention, FIG. 2 is a configuration diagram of one embodiment, FIG. 3 is a flowchart showing the processing performed in this embodiment, and FIG. 4 is a diagram showing the intake pipe from the engine speed NE. A graph corresponding to a map for determining a predetermined pressure P is shown. 1... Internal combustion engine 9... Water temperature sensor 10... Throttle valve 11... Throttle opening sensor 14... Intake pressure sensor 18... Rotation angle sensor (rotation speed sensor) 20...
Electronic control circuit 21...Diagnosis control circuit 22...Vehicle speed sensor abnormality warning lamp 23...Air conditioner switch 24...Vehicle speed sensor

Claims (1)

[Scope of Claims] 1. A vehicle speed system equipped with a vehicle that uses an internal combustion engine as a driving force source and includes at least intake pipe pressure detection means for the engine, rotational speed detection means for the engine, and temperature detection means for the engine. In the abnormality detection device of the detection means, the pressure determination means determines whether the intake pipe pressure detected by the intake pipe pressure detection means is equal to or higher than a predetermined pressure; A rotational speed determining means for determining whether the vehicle speed is equal to or higher than the vehicle speed; a temperature determining means for determining whether the temperature detected by the temperature detecting means is equal to or higher than a predetermined temperature; and a temperature determining means for determining whether the vehicle speed detected by the vehicle speed detecting means is zero or not. vehicle speed determination means for determining whether the pressure determination means is correcting the predetermined pressure used by the pressure determination means in accordance with the rotation speed detected by the rotation speed detection means; the pressure determination means, the rotation speed determination means, An abnormality detecting device for a vehicle speed detecting means, comprising: a determining means for determining that the vehicle speed detecting means is abnormal when each determination in the temperature determining means and the vehicle speed determining means is satisfied at the same time. 2. The vehicle speed detecting means according to claim 1, wherein the determining means is configured to determine that the vehicle speed detecting means is abnormal when each determination is satisfied simultaneously for a predetermined period of time. Anomaly detection device.