JPH0362573B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle speed control device for an internal combustion engine vehicle.
More specifically, the present invention relates to a vehicle speed control device that detects when gear slippage occurs during vehicle speed control and prevents the engine from increasing in rotation (revving up) when vehicle speed control is canceled.

In recent years, vehicle speed control devices that control the vehicle speed of internal combustion engine vehicles to a predetermined speed have become widely used, but in order to ensure safety, such devices do not allow constant speed driving control in the event of an abnormality in vehicle speed control. It is necessary to release the . A device for canceling constant speed driving control when some abnormality occurs in the vehicle speed control device is disclosed in, for example, Japanese Patent Application Laid-Open No. 55-29016.

By the way, when the speed of the vehicle is controlled by this vehicle speed control device to be a predetermined constant value, if a gear slip occurs due to driver carelessness or other reasons, the vehicle speed will decrease. In order to maintain a constant vehicle speed, the amount of fuel injected into the internal combustion engine increases, resulting in the problem that the engine continues to rev up. In order to eliminate the above-mentioned drawbacks, it is possible to configure the transmission to include a neutral switch to detect when the gear position has become the neutral position, and thereby limit the amount of fuel supplied to a predetermined value or less. However, it is extremely difficult to install such a switch in existing vehicles, and transmissions equipped with such a switch are expensive, and in any case, there is a problem in that the cost increases. ing.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a vehicle speed control device that can detect a gear-out condition and prevent engine speedup without providing a neutral switch.

The present invention provides a vehicle speed control device for controlling the vehicle speed of an internal combustion engine vehicle equipped with a manual transmission to a desired set speed. The present invention is characterized in that it includes means for detecting the rate of increase in the rotational speed of the internal combustion engine in response to a signal, and means for canceling vehicle speed control when the value of the rate of increase in the rotational speed exceeds a predetermined value.

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

FIG. 1 shows a block diagram of a vehicle speed control device according to the present invention. The vehicle speed control device 1 is a device for controlling the vehicle speed of a vehicle 3 using an internal combustion engine 2 as a drive source to an arbitrarily set desired target vehicle speed, and for detecting the rotational speed of the internal combustion engine 2. The vehicle 3 includes a rotation sensor 4 and a vehicle speed sensor 5 for detecting the vehicle speed of the vehicle 3. The rotation sensor 4 consists of a signal gear plate 7 fixed to the crankshaft 6 of the internal combustion engine 2 and an electromagnetic coil 8 disposed opposite to the signal gear plate 7.
This is a known sensor in which a voltage is induced in the electromagnetic coil 8 each time each cog formed around the signal gear plate 7 approaches or separates from the electromagnetic coil 8. Therefore, the rotation sensor 4 outputs a pulse train signal S ₁ consisting of pulses output at time intervals related to the rotation speed of the internal combustion engine 2, and the correspondingly provided interface circuit (I/O) 9 After being waveform-shaped at , it is output as the first signal _S2 .
On the other hand, the vehicle speed sensor 5 is connected to a meter cable (not shown) of a vehicle speed meter of a traveling device 11 that is connected to the internal combustion engine 2 via a transmission 10, and rotates as the meter cable rotates. It consists of a magnet plate 12 and a reed switch 13. As shown in the figure, the magnet plate 12 is alternately magnetized to N and S poles, and rotates with the rotation of the meter cable, so that the reed switch 13
Turn on and off. The reed switch 13 is connected to the input side of an interface circuit (I/F) 14, and a second signal _S3 whose level changes in response to the on/off state of the reed switch 13 is output from the output side. Ru. As can be seen from the above description, the second signal _S3 is a pulse train signal whose period changes in relation to the vehicle speed.

The first signal S ₂ having information regarding the speed of the internal combustion engine 2 and the second signal S ₃ having information regarding the vehicle speed are input to an input/output circuit (I/O) 15, where the respective signals are First data indicating the period
_D1 and second data _D2 are created as binary digital data. The first data D ₁ indicating the period of the first signal and the second data D ₂ indicating the period of the second signal output in this way are stored in the memory 17 by the central processing unit (CPU) 16. Ru.

The central processing unit 16 stores a program for controlling the vehicle speed to a predetermined target vehicle speed, and responds to control signals _S4 from each operation switch (not shown) provided on the control panel 18. The program is executed. Target vehicle speed data indicating a target vehicle speed is stored in advance in the memory 17 in response to the control signal _S4 , and the central processing unit 16 converts the vehicle speed into a desired target speed indicated by the target vehicle speed data. The position of the fuel adjustment member required for this is calculated based on the respective input data D ₁ , D ₂ and the control signal S ₄ . The calculation result in the central processing unit 16 is outputted from the input device 15 as a position signal S ₅ indicating the adjustment position of a fuel adjustment member (not shown) of the internal combustion engine 2 and inputted into the drive circuit 19 . A drive signal S ₆ is outputted from the drive circuit 19 in response to the position signal S ₅ and is applied to an actuator 20 connected to a fuel adjustment member (not shown), thereby adjusting the adjustment position of the fuel adjustment member according to the position signal S _{5 .} The vehicle 3 can be controlled to drive at the target vehicle speed.

FIGS. 2a and 2b show a flowchart of a program for controlling the vehicle speed described above. First, in step a, it is determined whether the control system shown in FIG. 1 is normal or not. If the control system is normal, the second data is
D ₂ is read and the second data D ₂ is transferred to memory 1.
7 and checks whether the value of the second data _D2 is within a predetermined normal range (step c). If there is an abnormality in the control system,
Proceed to step d, vehicle speed control is completely released,
A cruise lamp (not shown) provided in the control panel 18 (FIG. 1) is turned off (step e).
If the determination result in step c is YES,
In step f, the value of vehicle speed V is calculated based on the second data _D2 . This operation is performed on the second data
This is done by multiplying the reciprocal of D ₂ by a predetermined coefficient, and data regarding vehicle speed can be easily obtained. On the other hand, if the determination result in step c is NO, first in step g,
It is determined whether or not the vehicle is in a constant speed running control state, and if the determination result is NO, proceed to step f, and if the determination result is YES, the value of _D2 is outside the normal range. In step h, it is determined whether or not this has been detected a predetermined number of times _N1 consecutively in step c. If the determination result in step h is NO, proceed to step f,
In the case of YHS, a message indicating that the vehicle speed sensor is malfunctioning is displayed (step i), and control is completely canceled (step d).

In other words, if the value of the second data _D2 is out of the normal range for N _times or more consecutively while driving at a constant speed, it is determined that the vehicle speed sensor is malfunctioning and the control is completely canceled. , otherwise, in step f, the vehicle speed is calculated based on the data _D2 .

The calculation result of the vehicle speed is 28Km/
It is determined whether or not it is greater than or equal to h, and if the determination result is NO, the control is completely canceled. This means that the vehicle speed is 28
When the speed is slower than Km/h, there is virtually no need for vehicle speed control, so the control is forcibly canceled. If the vehicle speed is 28km/h or higher, step k
The gear position is determined at . Note that this discrimination reference value of 28 km/h can be set to other values as appropriate.

The gear position is determined based on the vehicle speed V calculated in step f and the engine rotational speed N, which is separately calculated based on the first data _D1 . That is, if the ratio between vehicle speed V and rotational speed N is defined as gear ratio R, gear ratio R≡N/V, and therefore R≡
It becomes D ₁ /D ₂ . By the way, the value of the gear ratio R is a unique value determined by the gear position in the transmission 10, and the gear ratio is R ₁ at the 1st gear position and R 1 at the 2nd gear position.
If R ₂ is R ₃ at the 3rd gear position, then the gear position at any given time can be determined by the ratio of D ₁ /D ₂ . In this embodiment, the predetermined gear ratio R ₁ at each gear position,
Setting a first gear ratio region I, a second gear ratio region, and a third gear ratio region including R ₂ and R ₃ , respectively,
It is configured to determine which gear ratio region the value of D ₁ /D ₂ belongs to, and to detect the gear position at that time from this result (see FIG. 3). Then, at both ends of each gear area, there is an abnormal gear ratio area.
(A), (B), (C), and (D) are set, and the gear position and vehicle speed sensor abnormality are determined depending on which region the D ₁ /D ₂ values belong to. It will be done.

_The above-mentioned determination procedure will be explained in detail with reference to _FIG . A determination is made as to whether or not the vehicle is traveling at a constant speed. If the vehicle is not traveling at a constant speed, the process proceeds directly to step m, but if the vehicle is traveling at a constant speed, it is determined whether or not the vehicle speed sensor is malfunctioning based on the calculated gear ratio. Executed by q. That is, in step m, it is determined whether the gear ratio is normal or not (whether the gear ratio belongs to ranges A to D shown in FIG. 3), and if the determination result is NO, it is further determined whether the gear ratio is abnormal. It is determined whether the condition has been detected a predetermined number of times N ₂ times in a row, and if it is determined that the condition is abnormal N ₂ times in a row, the control is completely canceled. In this way, by checking whether the gear ratio is normal or not, it is possible to determine a failure through mutual monitoring between the rotation sensor 4 and the vehicle speed sensor 5, which has the advantage of improving control reliability. There is. If the determination result in step p is NO, proceed to step m.

If the gear ratio is normal, it is further determined in step o whether or not the gear position determined in step k has changed; if no change in the gear position is detected, the process proceeds to step m;
On the other hand, when a change in gear position is detected, in step q, it is determined whether the change in gear position has changed a predetermined number of times _N3 consecutively. In this case, it is normally impossible to perform a gear change operation in which a change in gear position is detected _three times in a row. The release is performed (step d). On the other hand, even if there is a change in gear position, if there are no changes _N3 times in succession, the vehicle speed sensor is considered to be normal, and the process proceeds to step m.

Here, if at least one of the determination results in steps p and q is YES,
It is also possible to proceed to step d via step r, which indicates a failure of the vehicle speed sensor, and to completely cancel the control.

Step m is a step in which the vehicle speed V is calculated from the gear position determined in step k and the pre-calculated rotational speed N. Here, the value of the vehicle speed V is detected by the rotation sensor 4. It is calculated with the same accuracy as the rotational speed and is not directly related to the output of the vehicle speed sensor 5. That is, since the rotational speed N detected with high precision is converted into the vehicle speed V in consideration of the determination result in step k, it is possible to detect the vehicle speed with high precision.

After the value of the vehicle speed V at each time is calculated in this way, the program enters step s, in which the operating state of each switch (not shown) on the control panel 18 is checked.

Regarding the switch check operation in step s, if it is determined in step s that the brake switch is on, the routine proceeds to step t, where a process for temporarily canceling the vehicle speed control operation is performed. If it is determined in step s that the cruise switch provided on the control panel 18 is on, step u is entered and the actual vehicle speed value is determined based on the vehicle speed value obtained above and the desired target vehicle speed value. PI control is executed to make the vehicle speed match the target vehicle speed value. In step s, it is further determined whether or not a switch operation to change the target vehicle speed has been performed using a set switch or other switch, and if it is determined that a switch operation to change the target vehicle speed has been performed, , switch v is entered, which generates the ramp function necessary to change the current target vehicle speed in predetermined steps over time. If the temporary release has been performed, proceed to step e. Further, after a ramp function is generated in step v and the target vehicle speed is changed thereby, the process proceeds to step u, where PI control calculation is performed, and then the cruise lamp is turned on (step w).
A check is made to see if gear slippage has occurred (step x).

FIG. 4 shows a more detailed flowchart of step x for determining whether or not a gear is out of gear. The gear dropout determination step shown here is based on the rate of change α of the engine speed N per predetermined time.
It is determined whether gear slippage has occurred depending on whether or not (=ΔN/Δt) is greater than a predetermined value. In step _x1 , first, the rate of change α of the engine speed N is calculated. This calculation result is compared in magnitude with a predetermined reference rate of change K in step _x2 . The value of K is lower than the value of the engine speed change rate when the engine speeds up due to gear slippage, and is larger than the maximum value of the engine speed change rate that can occur when the gear is not out of gear. It is set as follows. Therefore, if α<K, it is assumed that the engine is not in a revving state, and the contents of the counter CTR are set to zero (step x ₃ ), and the process proceeds to the next step z, which will be described later.

If α≧K, 1 is added to the contents of the counter CTR (step x ₄ ), and then it is determined whether the contents of CTR are 3 or more (step
_x5 ). Here, the rate of change of engine speed α that is greater than K
was detected three times in a row, CTR≧
3, it is determined that the engine has spun up due to gear slippage, and the process proceeds to step d, where the vehicle speed control is completely canceled. If CTR<3, proceed to step z. In the example above, the CTR content is 3
In this embodiment, it is determined whether or not the engine has sprung up due to gear slippage depending on whether or not the engine speed has reached 3, but this value is not limited to 3 and can be set to any appropriate value.

In this way, the presence or absence of gear disengagement is detected by monitoring the rate of change of engine speed over time, so a neutral switch is provided to detect when the change lever of the transmission is in the neutral position. It is possible to reliably detect gear disengagement without causing any problems, and the functionality can be improved without increasing the price of the device. In addition, by monitoring the rate of change of engine speed over time, it is possible to minimize the sudden increase in engine speed that occurs when a gear slips out, compared to detecting gear slippage simply by determining whether the engine speed exceeds a predetermined value. Since it can be reliably detected within a short period of time, it becomes possible to promptly take appropriate measures against the gear slippage, and it is possible to reliably prevent the engine from racing up.

Furthermore, by providing such a step, even if the clutch switch fails, it is possible to detect that a gear change has been performed, and this has the advantage of canceling constant speed running and preventing engine revving. .

Step z is the target value Qdrive of the fuel supply amount according to the accelerator operation amount and the value of the fuel supply amount necessary to drive at a constant speed at each time.
This is a step in which a magnitude comparison is made with Qcruise and the larger data value is set as position control data indicating the target position of the fuel adjustment member. The position control data obtained in this manner is outputted as a position signal _S5 via the input/output device 15.

According to the present invention, by monitoring the rate of change in engine speed over time, it is possible to reliably detect a sudden increase in engine speed that occurs when a gear is disengaged in an extremely short period of time. Without the provision of such a gear, it is possible to quickly take appropriate measures against gear slippage, and engine racing can be reliably prevented. Therefore, this device can be installed on existing vehicles without any complicated modifications, and is highly economical.
Even for newly designed vehicles, it is possible to provide an inexpensive device that can reliably detect gear slippage and deal with it without increasing costs.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of a vehicle speed control device according to the present invention, and FIGS.
Figure 3 is a flowchart of the control program loaded into the device shown in Figure 3. Figure 3 is an explanatory diagram for explaining the determination of whether the calculated gear ratio value is normal or abnormal.
The figure is a detailed flowchart of the gear drop detection step shown in FIG. 2a. 1...Vehicle speed control device, 2...Internal combustion engine, 3...
Vehicle, 4... Rotation sensor, 5... Vehicle speed sensor, 1
0... Transmission, 11... Traveling device, 15... Input/output device, 16... Central processing unit, 19... Drive circuit, 20... Actuator, S ₁ ... Pulse train signal, S ₂ ... First signal, S ₃ ... second signal, S ₄ ... control signal, S ₅ ... position signal, D ₁ ... first data,
D ₂ ...Second data.

Claims (1)

[Claims] 1. A vehicle speed control device for controlling the vehicle speed of an internal combustion engine vehicle equipped with a manual transmission to a desired set speed, comprising: means for outputting a detection signal related to the rotational speed of the internal combustion engine; A vehicle speed control device comprising: means for detecting a rate of increase in the rotational speed of an internal combustion engine; and means for canceling vehicle speed control when the rate of increase in the rotational speed exceeds a predetermined value.