JP3523210B2 - Speed limiter - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, when the vehicle speed reaches a preset maximum value, prevents the vehicle from accelerating beyond the maximum value even if the accelerator pedal is depressed. The present invention relates to an improvement in a speed limiting device that automatically limits a fuel flow rate supplied to an engine. The present invention is a device developed for use as a tractor for towing a large-sized trailer in which the load of the engine greatly changes depending on the load capacity and other usage conditions, but it can also be widely used in other vehicles.

[0002]

2. Description of the Related Art There is known a device for limiting the vehicle speed so that if the maximum value of the vehicle speed is set in advance, the vehicle will not accelerate beyond the maximum value even when the accelerator pedal is depressed.
When this device is used, for example, the maximum value of vehicle speed (V _lim )
Is set to 90 km / h, when the vehicle speed (v) reaches 90 km / h when the vehicle is accelerated by stepping on the accelerator pedal, the fuel flow rate supplied to the engine is reduced even if the accelerator pedal is stepped on. Automatically limited and vehicle speed is 90
It is controlled so as not to exceed km / h.

This situation will be described with reference to FIG.
(A) shows a state in which the horizontal axis represents time t, the vertical axis represents vehicle speed v, and the vehicle speed gradually increases as the driver depresses the accelerator pedal, as indicated by the solid line. Figure 4 (b)
Is the flow rate F of the fuel supplied to the engine on the same time axis
FIG. During the period when the vehicle speed v is increasing, the fuel flow rate is F ₁ (ml / ml) corresponding to the depression amount of the accelerator pedal.
s, milliliters per second). When the vehicle speed reaches a preset maximum value (V _lim ), the automatic control means operates so as to prevent the vehicle speed from further increasing, and reduces the fuel flow rate from F ₁ to F ₂ by ΔF. At this time,
Ideally, the vehicle speed is controlled to be constant and flat at the maximum value (V _lim ), as indicated by the solid line in (a).

[0004]

However, if the amount of change .DELTA.F in the fuel flow rate is large, the vehicle is in a state where the engine brake acts, and the vehicle speed decreases as shown by the broken line in FIG. 4 (a). It will be. When the vehicle speed becomes lower than the maximum value (V _lim ), if the amount of depression of the accelerator pedal is maintained as it is, the automatic control means will now operate as shown in FIG.
The control is performed again to increase the fuel flow rate as indicated by the broken line in (b). That is, if the value of the conversion amount ΔF of the fuel flow rate when the vehicle speed reaches the maximum value is too large, the vehicle repeats deceleration and acceleration, and it takes time for the vehicle speed to stabilize.

When the amount of change ΔF in the fuel flow rate is too large, the vehicle repeatedly decelerates and accelerates as described above.
This gives the occupant vibration in the front-rear direction, which makes the occupant feel uncomfortable. If the value of this change amount ΔF is too small, the value in FIG.
As indicated by the dashed line in, causes increased beyond the maximum value of the vehicle speed (V _lim), it operates to thereafter slowly approaches a maximum value of the vehicle speed (V _lim) in the. This is not appropriate for the operation of the device that automatically regulates the maximum vehicle speed (V _lim ). Therefore, it is necessary to select the optimum value of this ΔF, but the optimum value of this ΔF varies depending on the magnitude of the engine load at that time even in the same vehicle. That is, ΔF depends on the weight of the cargo, the number of passengers, etc.
The optimum value of is always different. Particularly, in the case of a tractor for towing a large trailer, the engine load varies greatly depending on the usage situation.

[0006] In the tractor, the trailer may be traveled by itself without being pulled and forwarded, and at this time, the engine load is the smallest. Even when the trailer is being towed, the engine load changes greatly depending on whether there is no load or when the load is close to the maximum load.

The inventor of the present application, while considering improvement of riding comfort for the occupant of the tractor, shakes or vibrates when the occupant feels when the vehicle speed (v) input to the vehicle speed limiting device reaches the maximum value (V _lim ). Faced the problem. This shaking or vibration can be avoided by appropriately performing a driving operation such as loosening the accelerator pedal near the maximum value of the vehicle speed. However, since the vehicle speed limiting device is a device that prevents the vehicle speed from exceeding its maximum value without the driver's knowledge, this is not a problem that should be solved by driving operation, but an improvement of the device itself. Came to the idea that was necessary.

The present invention has been made against such a background, and an object thereof is to improve the riding comfort of a vehicle.
The present invention has an object to the vehicle speed (v) is when reaching a preset maximum value (V _{li m),} providing there is no speed limiter feel the occupant vibration or shaking. According to the present invention, when the vehicle speed (v) reaches a preset maximum value (V _lim ), the vehicle speed can be smoothly stabilized to the maximum value (V _lim ) without a large change. An object is to provide a speed limiting device.

[0009]

According to the present invention, when the vehicle speed (v) reaches the set maximum value (Vl _im ), the change ΔF in the fuel flow rate to be supplied to the engine is set to the engine load at that time. The biggest feature is to change according to the size of.

That is, the present invention comprises control means for reducing the fuel flow rate supplied to the engine by ΔF when the vehicle speed (v) input as vehicle speed information reaches the set maximum value (V _lim ) of the vehicle speed. In the speed limiting device, the Δ
Means for storing the value of F as a function map of the engine load (L) corresponding to the maximum value (V _lim ) of the vehicle speed, and the maximum value (V of the set vehicle speed (V
_lim ) and engine load (L), and means for obtaining the ΔF.

The engine load (L) is obtained by taking in the amount of depression of the accelerator pedal as a quantity value immediately before the vehicle speed reaches the maximum value (V _lim ), and the value of the vehicle acceleration at that time (the time differential value of the vehicle speed). It is desirable that the calculation is performed using software installed in the control means in association with the above. It is desirable that the means for storing and the means for calculating ΔF be implemented as software in one control circuit together with the control means.

In addition to determining the engine load (L) from the depression amount of the accelerator pedal as described above, the engine load can be input by the driver.
This is equipped with an operation switch that can be operated by the driver to switch and set "no trailer towing", "light load", "medium load", "heavy load", etc. It can be configured to be incorporated.

With such a configuration, immediately after the vehicle speed (v) reaches the set maximum value (V _lim ), the transition from the acceleration state to the constant speed is smoothly executed, and the driver and other passengers It is possible to avoid vibrations and shaking that would cause discomfort.

[0014]

1 is a block diagram of a vehicle speed limiting device according to an embodiment of the present invention. The control circuit 1 is composed of a program control circuit. The control means for reducing the fuel flow rate supplied to the engine by ΔF when the vehicle speed (v) input as vehicle speed information reaches the set maximum value (V _lim ) of the vehicle speed is implemented as software of the control circuit 1. ing. In a practical device, this control circuit 1 is part of a control device that controls the engine output in response to a driving operation.

An input / output circuit 2 is connected to the control circuit 1, and the rotation sensor 1 of the engine 3 is connected to the input / output circuit 2.
1 rotation information, clutch 4 operation information, transmission 5 position information, vehicle speed sensor 12 vehicle speed information, accelerator sensor 6 depression amount information, and maximum speed value provided in the driver's seat The signal of the (V _lim ) setting switch 7 is connected. Also, this input / output circuit 2
From the control output signal to the electronic governor 8 of the engine 3, and the fuel flow rate supplied to the engine 3 is controlled. A display signal indicating the operating condition of the vehicle speed limiting device is sent to the display 9 provided in the driver's seat.

The control circuit 1 operates in accordance with the information on the driving operation taken from the accelerator sensor 6 and the like, according to the engine 3
A control signal is sent to the electronic governor 8 to control the flow rate of fuel supplied to the engine 3. The control logic or software for this purpose is a well-known technique, and detailed description thereof will be omitted.

The features of the present invention will be described below.
The driver can operate the setting switch 7 to set the maximum speed value (V _lim ) of the vehicle. In this example, 60 km / h, which is the maximum speed when traveling on a general road,
90km / which is the maximum speed when traveling on a highway
Two types of h can be selected and set. 90 km as the maximum value (V _lim ) when driving on an expressway
It is assumed that / h is selected and set.

It is assumed that the transmission 5 is set to a corresponding forward traveling gear, the clutch 4 is in the meet state, and the accelerator pedal is depressed to accelerate the vehicle. As shown by the solid arrow in FIG. 4, when the vehicle is accelerated and the vehicle speed reaches the maximum value (V _lim = 90 km / h) over time, the control circuit 1 executes the control shown in FIG.

That is, the amount of depression of the accelerator pedal at this point is taken in, and the vehicle acceleration is calculated from the change in vehicle speed for the last few seconds (eg, 4 seconds). The engine load (L) is calculated from the ratio of the vehicle acceleration to the depression amount of the accelerator pedal. Then, the change amount ΔF of the fuel flow rate with respect to the engine load (L) is obtained by referring to the function map stored in the control circuit 1. Then, regardless of the amount of depression of the accelerator pedal at that time, a control signal is sent to the electronic governor 8 so as to reduce the fuel flow rate by the change amount ΔF. As a result, the maximum vehicle speed (v) is 90 km / h.
It will no longer be accelerated beyond.

FIG. 3 is a diagram showing an example of the function map.
The control map has a horizontal axis representing the engine load and a vertical axis representing the change amount ΔF of the fuel flow rate, and is a function as shown by the curve in the figure for each maximum value (V _lim ) of the vehicle speed. In this embodiment, as described above, the maximum value (V _lim ) is 60 km / h when traveling on a normal road and 90 k when traveling on a highway.
Two types of m / h are stored in the memory of the control circuit 1 in advance. The function stored in this memory is obtained from the results of various running tests for the vehicle type, and the change ΔF in the fuel flow rate obtained by referring to this function is the vehicle load at that time and It is an optimum value for the maximum vehicle speed (V _lim ). The control circuit 1 commands the electronic governor 8 to reduce the fuel flow rate by the ΔF, and the vehicle speed smoothly transitions to the maximum speed value (V _lim ).
At this time, unnatural shaking and vibration will not occur.

In the above embodiment, the description has been made of the case where the magnitude of the vehicle load is obtained from the depression amount of the accelerator pedal, but the magnitude of the vehicle load is not required to be so strict,
It is possible to improve the ride comfort accordingly. That is, the magnitude of the engine load can be determined by the driver's operation setting. In this case, the setting switch 7 is provided with a switch for selecting the maximum value (V _lim ) of the vehicle speed and a switch for selecting the vehicle load (L). The switch for selecting this vehicle load is shown in FIG.
As shown on the horizontal axis of, the vehicle load (L) is roughly divided into four stages such as "trailer non-connection", "loading none", "loading medium", and "loading large", which the driver can Set by operation. Then, the selection of the fuel flow rate variation ΔF executed by the control circuit 1 is similarly executed according to the set vehicle load (L) value in accordance with FIG.

[0022]

According to the present invention, the vehicle speed (v) is previously set.
Maximum value set (V_lim), The occupant shakes
Smooth maximum vehicle speed without any movement or shaking
Value (V _lim) Got a speed limiter that can
To be This device improves the riding comfort of the vehicle.
The present invention has a large engine load depending on the usage situation of the vehicle.
The effect is large when implemented on a changing tractor.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of an apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a control operation of a control circuit of the device according to the present invention.

FIG. 3 is a graph illustrating a function of a change amount ΔF of a fuel flow rate with respect to an engine load.

FIG. 4 is a diagram illustrating changes in vehicle speed (v) and control of fuel flow rate (F) with respect to the passage of time (t).

[Explanation of symbols]

1 control circuit 2 I / O circuit 3 engine 4 clutch 5 transmission 6 Accelerator sensor 7 Setting switch 8 electronic governors 9 Display 11 Rotation sensor 12 vehicle speed sensor

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI F02D 41/10 380 F02D 41/10 380Z (58) Fields investigated (Int.Cl. ⁷ , DB name) F02D 29/02 311 B60K 28/08 B60K 28/10 B60K 31/00 F02D 41/04 380 F02D 41/10 380

Claims (2)

(57) [Claims] 1. A speed limiting device comprising a control means for reducing a fuel flow rate supplied to an engine by ΔF when a vehicle speed (v) input as vehicle speed information reaches a maximum value (V _lim ) of a set vehicle speed. At the set value of the maximum value (V _lim ) of the vehicle speed .
And when the engine load (L) is large, the value of ΔF
Is large and the engine load is small, the value of ΔF is
A speed characterized by comprising means for storing as a small function map, and means for obtaining the ΔF from the set maximum value (V _lim ) of vehicle speed and engine load (L) with reference to this function map. Restriction device. 2. The speed limiting device according to claim 1, further comprising means for calculating the engine load (L) from a value corresponding to a depression amount of an accelerator pedal with respect to a vehicle acceleration.