JPS6257530B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle travel control device that allows a vehicle to travel at a constant speed by repeating slow acceleration and inertia travel within a predetermined speed range based on a set vehicle speed.

With conventional constant-speed driving devices, when you push the set switch, the current driving speed is set to the set vehicle speed.
From then on, the opening degree of the throttle valve is adjusted to increase _or decrease through the throttle actuator by comparing the running speed S of the vehicle with the set vehicle speed _S0 , and the running speed is kept constant to drive the vehicle at a constant speed.

Focusing on the fact that the vehicle is in a state where load fluctuations are small when traveling at a constant speed, the aim is to further save fuel during constant speed traveling.

The present invention has been made in view of the above points, and an object of the present invention is to provide a vehicle running control device that can further improve fuel efficiency when a constant speed running condition occurs.

In order to achieve the above object, the present invention is provided with a vehicle speed sensor a for detecting the running speed of the vehicle as shown in the invention block diagram in FIG. In a vehicle travel control device that automatically controls an acceleration/deceleration adjustment mechanism (c) according to a speed deviation to perform constant-speed travel, a predetermined speed range is defined based on the set vehicle speed (b), and slow acceleration is controlled as the speed range approaches the upper limit. a control means d for applying a slow acceleration signal to the acceleration/deceleration adjustment mechanism c for the purpose of operation, and stopping generation of the slow acceleration signal to generate an inertia running signal when the running speed reaches an upper limit; In response to the inertial running signal,
Cuts off the transmission of driving force from the engine to the wheels,
Further, the vehicle is characterized by being provided with inertial running means e that switches from normal running to inertial running by cutting off fuel supply to the engine.

The present invention will be described below with reference to embodiments shown in the drawings. FIG. 1 is an overall configuration diagram of the system, which uses a microcomputer that executes digital arithmetic processing according to a control program including a predetermined travel control program.

In FIG. 1, reference numeral 1 denotes a vehicle speed sensor, which generates a vehicle speed signal having a frequency corresponding to the traveling speed of the automobile. 2 is a brake switch that closes in conjunction with the depression of the brake pedal and generates a brake signal, and 3 is an uphill slope sensor that closes and generates an uphill signal when the vehicle starts to go uphill with a slope greater than a predetermined slope. It consists of a switch that generates. Reference numeral 4 denotes a throttle opening sensor, which generates an analog opening signal according to the opening of the throttle valve that adjusts the acceleration and deceleration of the automobile, and is composed of a potentiometer linked to the throttle valve. Reference numeral 5 is a return type set switch, which is pushed when setting constant speed running. 6
is a return type cancel switch, which cancels constant speed driving when manual operation of constant speed driving is canceled.

7 is a single-chip microcomputer that executes digital arithmetic processing according to a control program including a predetermined travel control program. When the crystal oscillator 8 is connected, it is activated by receiving a stabilized voltage of 5V from a stabilized power supply circuit (not shown) that starts operating when the engine key switch is turned on, and performs a number of predetermined calculation processes. It repeatedly issues control commands for constant speed driving and various control commands for other systems at a cycle of about 10 msec.For constant speed driving control, the vehicle speed signal from the vehicle speed sensor 1 and the brake signal from the brake switch 2 are used. , uphill signal from uphill sensor 3, analog opening signal from throttle opening sensor 4, set switch 5
It receives a set signal from the vehicle, a cancel signal from the cancel switch 6, etc., executes predetermined arithmetic processing by the travel control program, and issues a slow acceleration signal for slow acceleration travel or an inertia travel signal for inertia travel. It is something. This microcomputer 7 has a read-only memory (ROM) that stores control programs including a travel control program that defines calculation procedures for constant speed travel, and sequentially reads out the control programs in this ROM to correspond to the procedures. A central processing unit (CPU) that performs arithmetic processing,
Various data related to the calculation processing of this CPU is temporarily stored, and when the data is needed, the CPU
A clock generator that generates reference clock pulses for the various calculations mentioned above, and an A/D converter that converts analog signals into digital signals, with a memory (RAM) that can be read by It is manufactured by a semiconductor large-scale integrated circuit (LSI) (Intel 8022, USA), and the main component is an input/output (I/O) circuit section that adjusts the input and output of various signals.

Reference numeral 9 denotes a clutch drive circuit which is set in response to a clutch on command signal from the microcomputer 7, generates a clutch drive signal for actuating the electromagnetic clutch, and which is reset by a clutch off command signal. be. Reference numeral 10 denotes a motor drive circuit which receives signals from the microcomputer 7, such as an opening increase command, an opening decrease command, and an opening maintenance command, and generates corresponding motor drive signals. Reference numeral 11 denotes a throttle actuator, which is composed of a drive motor that drives the throttle valve to open and close, and an electromagnetic clutch that connects and disconnects the transmission of the rotational driving force of the drive motor to the throttle valve.
and each drive signal from the motor drive circuit 10. 12 is a valve drive circuit,
In response to a fuel cutoff command signal from the microcomputer 7, the fuel cut valve 13 is turned on to cut off fuel supply to the engine, and in response to a fuel return command signal, the fuel cut valve 13 is turned off to restore fuel supply. It is. 14 is a neutral control circuit, and a microcomputer 7
In response to the signal from the neutral command, a neutral control signal is applied to the electric automatic transmission control device 15 to switch the transmission mechanism to the neutral state, and at the same time, it is reset with a neutral release signal to release the neutral state and perform automatic transmission. The gear is returned to the controlled gear position.

The throttle actuator 11 constitutes an acceleration/deceleration adjustment mechanism, the microcomputer 7 and each drive circuit 9, 10, 12, 14 constitutes a control means, and the fuel cut valve 13
The automatic transmission control device 15 constitutes an inertial traveling means. Further, the clutch drive signal and the motor drive signal correspond to the slow acceleration signal, and further, the valve drive signal and the neutral drive signal from the valve drive circuit 12 correspond to the inertia running signal.

Next, in the above configuration, its operation is shown in FIG.
This will be explained with reference to the calculation flowcharts in FIGS. 3 and 4 and the characteristic diagram in FIG. 5.

FIG. 2 is a calculation flowchart showing the calculation processing of the microcomputer 7 according to the travel control program.
FIG. 3 is a calculation flowchart showing detailed calculation processing of the economy driving control routine in FIG. 2, FIG. 4 is a calculation flowchart showing detailed calculation processing of the rhythm driving control routine in FIG. 3, and FIG. FIG. 3 is a characteristic diagram showing speed changes during economy driving.

First, when the key switch is turned on to start driving the car, a stabilized power supply circuit (not shown) starts operating, and the stabilized voltage is supplied to various circuits including the microcomputer 7, and the microcomputer 7 becomes operational. After going through an initial set operation including canceling various flags, the process proceeds to the calculation processing of the travel control program, and thereafter the calculation processing of the control program including this travel control program is performed several times.
Repeat at a cycle of 10msec.

In this travel control program, first the second
When the set switch determination step 101 in the figure is reached, it is determined whether or not the set switch 5 has been operated, but since it has not been operated at the start of operation, the determination is NO, indicating that the cancel switch 6 has been operated. Proceeding to cancel judgment step 102, which judges whether or not there is, the judgment becomes NO.
Proceeding to brake determination step 103, which determines whether brake switch 2 has been activated, the determination is also NO.
, and proceed to economy flag determination step 111. At this time, since the flag was released during the initial set operation, the determination becomes NO, and the neutral release step 112 and the clutch off step are performed.
113, execute the calculation to proceed to fuel return step 114,
Neutral control circuit 14 is turned off, valve drive circuit 12 and fuel cut valve 13 are turned off, and clutch drive circuit 9 is also reset so that throttle actuator 11 remains off.

Then, start the engine of this car,
Even after starting to run, the same calculation process as above is performed,
Furthermore, when the brake pedal is temporarily depressed when starting, etc., a brake signal is generated from the brake switch 2, and the judgment in the brake judgment step 103 becomes YES, and the process goes through the economy flag release step 104. , the others perform similar calculations, and the throttle actuator 11, fuel cut valve 13, and neutral control circuit 14
Both are kept in the off state.

While driving on flat ground in this state, when the driver presses the set switch 5 at time _t1 in the characteristic diagram of FIG. 5 to shift to constant speed driving under automatic control, the set switch of FIG. 2 of the travel control program is activated. When the vehicle reaches determination step 101, the determination becomes YES, and vehicle speed calculation step 105 is reached.
Then, the vehicle speed S is calculated based on the vehicle speed signal from the vehicle speed sensor 1, and the vehicle speed S is set and stored as the set vehicle speed _S0 (=S) in the vehicle speed set step 106, and the clutch on command is issued in the clutch on step 107. The signal is applied to the clutch drive circuit 9 to turn on the electromagnetic clutch in the throttle actuator 11, and the process proceeds to the next throttle initial control step 108, where the throttle valve is adjusted to the initial opening θ ₀ corresponding to the set vehicle speed S ₀ . Motor drive circuit 10 to control the opening degree
An opening control command signal is applied to the throttle actuator 11 to complete the initial throttle control, and the economy flag and acceleration flag are set through the economy flag set step 109 and the acceleration flag set step 110, and the engine starts running at a constant speed. After completing the initial control operation, the process proceeds to economy flag determination step 111. Then, the determination in the economy flag determination step 111 is reversed from NO to YES, and the calculation to proceed to the economy travel control routine 200 is executed. After the push operation of the set switch 5 is stopped upon completion of this initial control operation, the determination at the set switch determination step 101 becomes NO.
Economy flag determination step is performed through cancel determination step 102 and brake determination step 103.
111, the operation proceeds to the economy travel control routine 200 and is repeated.

As a result, in the economy driving control routine 200, the vehicle speed sensor 1, the uphill sensor 3,
Arithmetic processing for controlling the opening of the throttle valve by the throttle actuator 11 based on each signal from the throttle opening sensor 4, controlling the on/off of the fuel cut valve 13, and controlling the automatic transmission control device 15 to set the throttle to neutral or cancel neutral. Execute.

That is, the economy driving control routine 200
Then, the vehicle speed calculation step 201 in FIG. 3 is reached, and the current vehicle speed S is calculated based on the vehicle speed signal from the vehicle speed sensor 1.
is calculated, and the determination in the uphill determination step 202 becomes NO, and the process proceeds to the rhythm traveling control routine 300, arriving at the upper limit determination step 301 in FIG. At this time, since the vehicle speed S is almost equal to the set vehicle speed _S0 immediately after the set operation, the determination becomes NO, and the process proceeds to lower limit determination step 303, where the determination also becomes NO, and the process proceeds to acceleration flag determination step 305, where the acceleration flag Since the acceleration flag was set in the set step 110, the determination becomes YES, and the vehicle goes through the neutral release step 309 and the fuel return step 310 to maintain the automatic gear shift control state and fuel supply state as in the previous driving. , proceed to slow acceleration control step 311.

Thereafter, the same calculation process as above is repeated, and the throttle opening degree by the throttle actuator 11 is increased by a predetermined value by the calculation in the slow acceleration control step 311, and the traveling speed is gradually increased toward time _t2 in FIG. Performs slow acceleration control to raise the vehicle.

As a result, the vehicle speed at time t ₂ is (S ₀ + 5) Km/
When it rises to h, the rhythm running control routine 30
When the upper limit determination step 310 is reached at 0, the determination is reversed from NO to YES, and the process proceeds to the acceleration flag release step 302 to release the acceleration flag.
The determination at the next acceleration flag determination step 305 is reversed from YES to NO, and the process advances to fuel cut step 306.
A fuel cut command signal is applied to the valve drive circuit 12 to turn on the fuel cut valve 13 to shut off the fuel, and in a neutral command step 307, the neutral command signal is sent to the neutral control circuit 1.
In addition to step 4, the automatic transmission control device 15 is forcibly switched to the neutral state and the throttle return step is executed.
At 308, the throttle opening degree is returned to the initial value _θ0 . As a result, the vehicle shifts to inertial running, and the vehicle speed begins to slowly decrease. At this time,
When the vehicle speed S decreases below (S ₀ +5) Km/h, the determination in the upper limit determination step 301 in FIG. 4 becomes NO, but the determination in the lower limit determination step 303 also becomes NO, and the acceleration flag remains cleared. Therefore, acceleration flag judgment step 305, fuel cut step 306, neutral command step 307, throttle return step
The calculation process through step 308 is repeated to maintain inertial running.

By continuing this inertial running for about 10 seconds, the vehicle speed gradually decreases, and at time _t3 , the vehicle speed S becomes (S ₀
-5) When the speed decreases to Km/h, the rhythm driving control routine 300 passes through the upper limit determination step 301 and reaches the lower limit determination step 303, when the determination is made.
The answer is reversed to YES, and the process advances to acceleration flag setting step 304 to set the acceleration flag. Therefore, the determination at the next acceleration flag determination step 305 is reversed to YES, and the process proceeds to a neutral release step 309 where the neutral release signal is sent to the neutral control circuit 14.
In addition, the automatic shift control device 15 is released from the neutral state and switched to the automatic shift state, and the process proceeds to a fuel return step 310, where an off signal is applied to the valve drive circuit 12, and the fuel cut valve 13 is turned off to enter the fuel supply state. Return and slow acceleration control step
Proceed to 311. At this time, the automatic transmission control device 1
Since the vehicle speed is sufficiently high at the time of switching to the automatic transmission state by canceling the neutral in step 5, the automatic transmission control device 15 controls the top gear position, and therefore the shock of the automobile at the time of switching to the automatic transmission state is It is small, does not interfere with driving, and provides relatively smooth switching control.
Then, the process proceeds to slow acceleration control step 311 and starts slow acceleration control to increase the vehicle speed by 10 km/h from (S ₀ -5) Km/h to (S ₀ +5) Km/h in about 5 seconds. do. As a result, the vehicle speed S starts to gradually increase, and when it becomes higher than (S ₀ −5) Km/h, the fourth
Although the determination in lower limit determination step 303 in the diagram is NO,
Since the acceleration flag remains set, the calculations through acceleration flag determination step 305, neutral release step 309, fuel return step 310, and slow acceleration control step 311 are repeated to maintain control of slow acceleration driving.

Thereafter, by executing the same calculation process as above, the lower limit value (S ₀ -5) based on the set vehicle speed S ₀ is determined.
Between the speed range of Km/h and the upper limit (S ₀ + 5) Km/h, the vehicle performs slow acceleration driving until the vehicle speed S reaches the upper limit from the lower limit, and when it reaches the upper limit, it switches to inertial driving. Rhythm running is controlled to maintain the inertia running until the inertia drops to the lower limit. here,
In the conventional technology that adjusts the opening of the throttle valve to keep the traveling speed constant and performs constant speed driving, if the throttle valve is fully closed to perform inertial driving, a certain amount of fuel will be lost depending on the vehicle speed. is supplied. In contrast, in this embodiment, when performing inertial travel, the fuel cut valve 13 is turned on to actively cut off the fuel, so that fuel can be saved accordingly, resulting in improved fuel efficiency.
In addition, since the automatic transmission control device 15 is forcibly switched to the neutral state at the same time as inertia running, the vehicle speed S does not quickly decrease due to so-called engine braking, and the vehicle speed S is mainly reduced by only frictional force. affected and gradually decreases. Therefore, it is possible to lengthen the period for the vehicle speed S to reach its lower limit from its upper limit, and in other words, it is possible to lengthen the period during which fuel is cut off, resulting in further improvement in fuel efficiency. Become.

As a result, efficient slow acceleration control and inertia driving are utilized to achieve economical driving, which is average constant speed driving that saves fuel consumption as much as possible.

Next, when an uphill slope with a slope greater than a predetermined slope is reached during the above economy driving, an uphill signal is generated from the uphill sensor 3 and is applied to the microcomputer 7. Therefore, in the economy driving control routine 200, the vehicle speed When the uphill judgment step 202 is reached after passing through the calculation step 201, the judgment is NO.
to YES, rhythm driving control routine 3
The process does not proceed to 00, but proceeds to neutral release step 203. As a result, rhythm travel control is stopped. Then, the neutral state is canceled in the neutral release step 203, and the fuel supply state is returned to the fuel supply state in the fuel return step 204, and the vehicle speed S is higher than the value (S ₀ + α) of the set vehicle speed S ₀ plus the dead zone width α. A first vehicle speed determination step 205 determines whether the vehicle speed S is lower than _S0 , a throttle opening reduction step 206 which decreases the opening of the throttle valve for deceleration, and a second vehicle speed determination step 207 which determines whether the vehicle speed S is lower than S0. , a throttle opening increasing step 208 in which the opening of the throttle valve is increased to increase the speed, the vehicle speed S is S ₀ and (S ₀ +
Throttle opening holding step that maintains the opening of the throttle valve when it enters the dead zone between α)
Set vehicle speed S by combination of each calculation of 209 Vehicle speed S ₀
is maintained at a constant value, the vehicle smoothly transitions to uphill running, and normal constant speed running can be performed without using inertia running during uphill running.

After that, when the uphill slope reaches level ground, the uphill signal from the uphill sensor 3 disappears, so the economy driving control routine 200 starts from the vehicle speed calculation step 201 and the uphill determining step 202 shown in FIG. 3 to the rhythm driving control routine 300. The above-mentioned rhythm running is controlled by repeating the calculations proceeding to step 1, and it is possible to shift to average constant speed running utilizing inertia running.

Next, when the brake pedal is depressed during economy driving, a brake signal is generated from the brake switch 2 and applied to the microcomputer 7, so when the brake judgment step 103 in the driving control program is reached, the judgment becomes YES. Proceed to economy flag release step 104 to release the economy flag. Therefore, the next economy flag judgment step 111 will be judged as YES.
Reverse to NO, economy driving control routine 20
Instead of proceeding to 0, arithmetic processing is executed to proceed to a neutral release step 112, a clutch off step 113, and a fuel return step 114, thereby canceling the economy driving control and shifting to a normal driving state.

On the other hand, when the driver manually operates the cancel switch 6 during the above-mentioned economy driving, a cancel signal is generated from the cancel switch 6 and applied to the microcomputer 7, so that the cancellation determination step 102 in the driving control program is performed.
When the brake pedal is reached, the judgment becomes YES, and the process proceeds to the economy flag release step 104 to release the economy flag, and the process proceeds from the economy flag judgment step 111 to the neutral release step 112 to the clutch off step 113 in the same way as when the brake pedal is depressed. Then, the arithmetic processing that proceeds to the fuel return step 114 is executed, the economy driving control is canceled, and a transition is made to the normal driving state.

In the above-mentioned embodiment, the push operation of the set switch 5 is used as the constant speed driving condition, but when it is detected that stable driving without any speed fluctuation occurs for a certain period of time is detected, the vehicle automatically shifts to constant speed driving. You may also do so.

Further, although the vehicle speed S at the time of push operation of the set switch 5 is stored and used as the set vehicle speed _S0 , it is also possible to manually set the vehicle speed using a dial.

In addition, the predetermined speed range based on the set vehicle speed S ₀ is defined as (S ₀ +5) Km/h and (S ₀ -5) Km/h, but the range width is 10
10% of the set vehicle speed S ₀ (S ₀ /10) instead of Km/h minute
minutes or other values, or the set vehicle speed.
Although the speed range is defined above and below the set speed S ₀ as the center, the speed range may be set only above or below the set speed S ₀ .

In addition, a microcomputer 7 is used as a control means.
Although a similar process is shown using a hardware electronic circuit, it is also possible to perform similar processing using a hardware electronic circuit.

Furthermore, instead of switching to the neutral state using the automatic transmission control device 15, the clutch may be controlled to the disengaged state in a manual transmission type vehicle.

Furthermore, 10Km/h in slow acceleration control step 311
In this example, the throttle opening is increased by a predetermined amount corresponding to the vehicle speed for slow acceleration, but the throttle opening is adjusted so as to linearly increase the vehicle speed based on the vehicle speed signal from the vehicle speed sensor 1. Good too.

As described above, according to the present invention, a predetermined speed range is defined based on the set vehicle speed when a constant speed running condition occurs, and between the lower limit value and the upper limit value of this speed range, slow acceleration running, inertia The vehicle is repeatedly driven, and when running inertia, the transmission of driving force from the engine to the wheels is actively cut off, and the fuel supply to the engine is actively cut off, making it even more difficult. This has the excellent effect of improving the fuel efficiency of the vehicle and also allowing the driver to drive at a constant speed on average.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention;
Figure 2 is a calculation flowchart showing the calculation processing of the microcomputer in Figure 1, Figure 3 is a calculation flowchart showing the detailed calculation processing of the economy driving control routine in Figure 2, and Figure 4 is the calculation flowchart in Figure 3. FIG. 5 is a characteristic diagram for explaining the operation of the present invention, and FIG. 6 is an inventive configuration diagram showing the configuration of the present invention. 1...Vehicle speed sensor, 5...Set switch,
7, 9, 10, 12, 14... A microcomputer, a clutch drive circuit, a motor drive circuit, a valve drive circuit, and a neutral control circuit forming a control means, 11... A throttle actuator forming an acceleration/deceleration adjustment mechanism, 13, 15...Fuel cut valve and automatic transmission control device that constitute inertial traveling means.

Claims (1)

[Scope of Claims] 1. A vehicle that is equipped with a vehicle speed sensor that detects the running speed of the vehicle, and when a constant speed running condition occurs, an acceleration/deceleration adjustment mechanism is automatically controlled based on the deviation of the running speed from the set vehicle speed, and the vehicle runs at a constant speed. In the travel control device, a predetermined speed range is defined based on the set vehicle speed, and a slow acceleration signal is applied to the acceleration/deceleration adjustment mechanism for slow acceleration toward the upper limit value, and when the travel speed reaches the upper limit value. control means for stopping the generation of the slow acceleration signal and generating an inertia drive signal when the slow acceleration signal is reached; A vehicle running control device comprising an inertial running means that switches from normal running to inertial running by cutting off fuel supply to an engine.