JPH07108620B2 - Vehicle constant-speed traveling device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a constant speed traveling device for vehicles such as automobiles.

(Prior Art) Generally, an electronically controlled fuel injection device determines that the engine is decelerating when the rotation speed of the engine is equal to or higher than a predetermined value and the throttle valve is close to full closure, and stops fuel injection to reduce the drive torque. It has a function to suppress the occurrence.

In addition, recently, in addition to such a fuel cut function,
Attempts have been made at the same time to use a constant speed traveling device for automatically traveling a vehicle at a constant speed. In such a constant-speed traveling device, when traveling on a long downhill, the traveling inertial force of the vehicle itself may be large and the generation of the driving torque may be extremely small. Therefore, in order to maintain the target vehicle speed, the throttle opening is performed. The degree may be almost fully closed. At this time, when the throttle opening is fully closed, the electronically controlled fuel injection device stops fuel injection as described above, so the vehicle is further decelerated and falls below the target vehicle speed. Therefore, the constant speed traveling device operates so as to open the throttle valve to inject fuel again, and this reinjection causes a temporary shock due to a large acceleration to accelerate the vehicle. After that, when the target vehicle speed is exceeded, the throttle valve is closed again.

As described above, when the throttle valve is opened and closed from the fully closed state, the fuel injection is repeatedly stopped and restarted by the electronically controlled fuel injection device, and mainly the shock at the time of restart is great and the ride comfort of the occupant is deteriorated.

As a conventional device for solving such a problem,
For example, there is one described in JP-A-60-135334. In this device, the gain of the constant speed traveling control is reduced for a predetermined time after the fuel injection is stopped, and the number of repetitions of the fuel injection stop / restart per unit time is reduced.

(Problems to be Solved by the Invention) However, in such a conventional vehicle constant-speed traveling device, the constant-speed traveling control gain is reduced for a predetermined time after the fuel cut to slowly open and close the throttle valve. However, since the number of shocks is reduced, the mode in which the engine drive torque generation is controlled by the opening / closing operation of the throttle valve remains.Therefore, when the operation amount during opening / closing is large. In such cases, there was a problem that the deterioration of riding comfort still remained due to the shock.

Therefore, the present invention prohibits vehicle speed control by repeating stop and restart of fuel injection when the target vehicle speed and the actual vehicle speed are in a predetermined condition in the fuel cut state, and also responds to the difference from the target vehicle speed. By operating the opening of the throttle valve for constant speed traveling, the acceleration shock associated with the vehicle speed control is reduced, and the ride comfort is improved.

(Means for Solving Problems) In order to achieve the above object, the vehicle constant-speed traveling device according to the present invention has a driving state detecting means for detecting the driving state of the engine as shown in the basic conceptual diagram of FIG. a, a traveling state detecting means b for detecting the traveling state of the vehicle, a fuel cut command means c for instructing a fuel cut when the engine is within a predetermined deceleration operation range, and a constant speed traveling control for instructing the target. Target setting means d for setting the vehicle speed, calculating means e for calculating the difference between the target vehicle speed and the actual vehicle speed, a fuel supply amount is calculated according to the operating state of the engine, a supply signal is output, and fuel cut is commanded. A supply amount calculation means f for stopping the output of the supply signal, a fuel supply means g for supplying fuel to the engine based on the supply signal, and a fuel cut command and a constant speed traveling command. And in the period when the difference between the actual vehicle speed and the target vehicle speed is smaller than the predetermined value,
The fuel cut command is held regardless of the operating state of the engine, and the holding means h for canceling the holding of the fuel cut command when the difference between the actual vehicle speed and the target vehicle speed becomes larger than a predetermined value, and the fuel cut command. While the high-speed running command is being issued, and in the period when the difference between the actual vehicle speed and the target vehicle speed is smaller than a predetermined value, while controlling the engine output by adjusting the air flow rate to the cylinder, the control value is calculated. When the difference between the actual vehicle speed and the target vehicle speed becomes larger than a predetermined value, the vehicle speed control means i which calculates a control value for adjusting the fuel supply amount to control the engine output, and the engine output is operated based on the output of the vehicle speed control means. And output adjusting means j for

(Operation) In the present invention, when the fuel cut control and the constant speed control are used together,
If the difference between the target vehicle speed and the actual vehicle speed is smaller than a predetermined value, constant speed traveling is maintained by increasing or decreasing the intake air amount, while if the difference between the target vehicle speed and the actual vehicle speed is larger than the predetermined value, fuel supply is performed. The constant speed running is maintained by the increase / decrease operation of the amount.

Therefore, excessive control of the engine output when the difference between the target vehicle speed and the actual vehicle speed is small is avoided, so that the shock is alleviated and the riding comfort is improved.

(Example) Hereinafter, the present invention will be described with reference to the drawings.

2 to 7 are views showing an embodiment of the present invention.

First, the configuration will be described. In FIG. 2, this device is roughly divided into a fuel injection control unit 1 and a constant speed traveling control unit 2.

The fuel injection control unit 1 is composed of an air flow meter 3, crank sensors 4, a throttle valve switch 5, an injector 6 and a microcomputer 7.

The air flow meter 3 is of a hot wire type or a flap type, and detects the amount of intake air to the engine. The crank angle sensor 4 detects the crank angle of the engine and generates a pulse at every predetermined crank angle. Throttle valve switch 5
Detects the opening of the throttle valve, closes the contact near full closure, and opens the contact in the open state. Air flow meter 3, crank angle sensor 4, throttle valve switch 5
Constitutes an operating state detecting means 8, and a signal from the operating state detecting means 8 is inputted to the microcomputer 7.

The microcomputer 7 has a function as a supply amount calculation means and a fuel cut command means, and includes a CPU 9, a ROM 10 and an R
AM11, A / D converter 12, input port 13 and output port 14
It is composed of A / D converter 12 is an air flow meter 3
The output of is converted to A / D and output to the CPU9.The CPU9 reads the required external data from the input port 13 and the A / D converter 12 according to the program written in the ROM10.
While exchanging data with M10 and RAM11, processing values required for fuel injection and fuel cut are calculated and processed.
The data processed as necessary is output to the output port 14. Signals from the crank angle sensor 4 and the throttle valve switch 5 are input to the input port 13, and an injection signal is output to the injector 6 from the output port 14. The injector 6 opens based on the injection signal Si to inject fuel into the engine.

Constant, constant speed running control unit 2 is a vehicle speed sensor 15, brake switch 16, accelerator switch 17, command switch
18, an actuator 19, a microcomputer 20, and a holding circuit 21.

The vehicle speed sensor 15 rotates a magnet with a speedometer cable, and outputs a pulse signal proportional to the vehicle speed in combination with a reed switch. The brake switch 16 works in conjunction with the brake pedal to detect a minute stroke of the brake pedal and output a signal, and the accelerator switch 17 detects a minute stroke of the accelerator pedal and outputs a signal.

Further, the command switch 18 has a function as a target setting means, a set switch for instructing constant speed running (not shown), an accelerator switch for instructing acceleration,
It consists of a resume switch for returning to the original state after the constant speed running is canceled, and outputs ON and OFF signals of each switch.

The vehicle speed sensor 15, the brake switch 16 and the accelerator switch 17 constitute a traveling state detecting means 22. The signal from the traveling state detecting means 22 is input to the microcomputer 20, and the signals from the crank angle sensor 4 and the throttle valve switch 5 are also input to the microcomputer 20. Also, the microcomputer 20
Is connected to the throttle valve switch 5 via a holding circuit (holding means) 21.

That is, as shown in detail in FIG. 3, the holding circuit 21 is composed of a relay 23 and a resistor R ₂ and has a contact 23 a of the relay 23.
One end of is connected to the power source through the resistor R ₂ , and the other end is connected to the signal line of the throttle valve switch 5. Further, one end of the coil of the relay 23 is connected to the power source, and the other end is connected to the microcomputer 20. The holding circuit 21 closes the contact 23a of the relay 23 when an ON signal is input under a predetermined condition according to a command from the microcomputer 20 and causes the microcomputer 7 to turn on the throttle valve switch regardless of whether the throttle valve switch 5 is opened or closed. Give the signal of.

The microcomputer 20 has a function as a calculation means and a vehicle speed control means, and is composed of a CPU 24, a ROM 25, a RAM 26, an input port 27 and an output port 28, and calculates and processes a processing value required for constant speed running of the vehicle. The data is output to the output port 28. The input port 27 has a running state detecting means 2
2. Signals from the command switch 18, the holding circuit 21, the crank angle sensor 4, and the throttle valve switch 5 are input, and a travel control signal Sc is output from an output port 28 to an actuator (output adjusting means) 19. The actuator 19 includes, for example, a vent valve 31, a safety valve 32, and a vacuum valve 33, as shown in FIG. Is connected to a negative pressure source (eg, intake manifold or negative pressure pump). The other end of each valve communicates with a negative pressure chamber 36 formed by a casing 34 and one side of a diaphragm 35, and the other side of the diaphragm 35 is connected to a throttle valve shaft 38 via a wire 37. It

The actuator 19 opens and closes based on the travel control signal, and when the vacuum valve 33 is opened, a negative pressure is introduced into the negative pressure chamber 36 to rotate the throttle valve in the opening direction, and conversely when the vacuum valve 33 is closed, The vent valve 31 is opened, the atmosphere is introduced into the negative pressure chamber 36, and the throttle valve is rotated in the closing direction. That is, the opening of the throttle valve is operated based on the traveling control signal Sc to adjust the output of the engine.

The output adjustment amount in this case is different at the time of fuel injection and at the time of fuel cut, the engine output is adjusted by the fuel injection device at the time of fuel injection, and the engine output is adjusted by pumping loss of intake air at the time of fuel cut.

Next, the operation will be described.

In the present device, the fuel injection control unit 1 calculates the intake air amount per unit rotation, calculates the fuel injection time (fuel injection amount) to keep the mixture ratio at a predetermined value, and outputs the injection signal every unit rotation. 6 is output and fuel is injected. Further, when the engine speed is equal to or higher than a predetermined value and the throttle valve is in the vicinity of fully closed (contact closed state of the throttle valve switch 5), it is determined that deceleration is performed, and fuel cut is performed.

On the other hand, the constant speed traveling control of the vehicle is performed by the constant speed traveling control unit 2, and this constant speed traveling control is performed according to the programs shown in FIGS.

FIG. 5 is a main routine for constant speed traveling control, and this routine is executed once every predetermined time (for example, every 500 msec).

In FIG. 5, first, at P ₁ , it is determined whether or not the vehicle speed setting switch of the command switch 18 is set. The vehicle speed set switch is used to set an arbitrary constant speed running value by operating the driving vehicle.
It is set at P ₂ and P ₃ . When the vehicle speed set switch is set, it calculates the current actual vehicle speed in P _2. This calculation is performed by counting the vehicle speed pulses input from the vehicle speed sensor 15 within the repetition period (500 msec) of this routine.

Thus the actual vehicle speed of the current calculated by is constant speed running value corresponding to the demands of the driver, then it was stored in the target vehicle speed storage area as the target vehicle speed in P _3, constant speed running flag P ₄ Set CF (CF = 1) and return. The constant speed running flag CF is a graph showing whether or not the vehicle has been instructed to run at a constant speed. When CF = 1, it means that the vehicle is in a constant speed running state.
When CF = 0, it indicates the cancellation of the same state.

On the other hand, if the vehicle speed set switch is not set in step P ₁ above, the setting status of the constant speed running flag CF in the previous routine is checked in P ₅ . When the CF = 0 it is determined that the instruction to cruise control has been canceled, the initial set of output of the drive control signal Sc at P _6. As a result, the vacuum valve 33 of the actuator 19 which responds to the traveling control signal Sc is closed, and the vent valve 31 and the safety valve 32 are closed.
Are closed, and the actuator 19 does not apply the turning force to the throttle valve.

Then, at P ₇ , the energization of the relay 23 of the holding circuit 21 is cut (stopping the output of the ON signal) to open the contact 23a, and at P ₈ , the holding flag HF is reset (HF = 0) and the process returns. . Therefore, the function of the holding circuit 21, that is, the function of sending a signal corresponding to ON of the throttle valve switch 5 to the microcomputer 7 regardless of opening / closing of the throttle valve switch 5 is canceled. The holding flag HF is the holding circuit 21.
Is a flag indicating the presence or absence of the above function, and when HF = 1, it indicates that the same function exists, and when HF = 0, it indicates the released state.

On the other hand, when CF = 1 in P ₅ , it is judged that the vehicle is under the constant-speed traveling command, and the process proceeds to the steps following P ₉ to perform the processing required for the constant-speed traveling.

First, the throttle valve switches the engine speed N in P ₉ a predetermined value Nc (e.g., using the same value as judgment rotation speed suitable for performing the fuel cut) compared to, at P ₁₀ when the N ≧ Nc It is determined whether or not 5 is ON. The calculation of the engine speed N is performed in a subroutine JOB2 described later. When the throttle valve switch 5 is ON, it is judged that the vehicle is under the fuel cut condition, the holding circuit 21 is activated at P ₁₁ (the ON signal is output from the microcomputer 20), and the holding flag HF is set. Then P
Go to ₁₂ .

Therefore, under this condition, the holding circuit 21 sends a signal corresponding to ON of the throttle valve switch 5 to the microcomputer 7 regardless of whether the throttle valve switch 5 is opened or closed.

On the other hand, at this time, the output of the injection signal Si in the microcomputer 7 is stopped because the fuel cut condition is satisfied, and the engine shifts to the fuel cut state. On the contrary,
Throttle valve switch 5 and P ₁₀ when N <Nc, it is determined that fuel cut condition is not satisfied when the OFF in P _9, the process proceeds to P ₁₂ to jump P _11. In this way, it is divided into two functions depending on whether the fuel cut condition is satisfied.

First, the case of fuel cut will be described.

(I) When running at a constant speed with fuel cut First, calculate the actual vehicle speed this time again on P ₁₂ , and set this on P ₁₃ to P ₃
Compare with the target vehicle speed stored in. The difference between the target vehicle speed and the actual vehicle speed is [Delta] S ([Delta] S = target speed - actual vehicle speed) (hereinafter, referred to as vehicle speed difference) when is positive, i.e., checks the hold flag HF when towards the actual vehicle speed is lower than the target in the P ₁₄ To do. When HF = 1, the vehicle speed difference ΔS is further compared with a predetermined value So at P ₁₅ . When ΔS ≧ So, it is necessary to rapidly accelerate the vehicle to bring it closer to the target value, so it is judged that fuel injection is better, and the function of the holding circuit 21 is released in P ₁₆ and held in P ₁₇ . Reset flag HF and proceed to P ₁₈ . Also, at P ₁₄ , HF =
When it is 0, it is judged that the holding release request has been made in the previous routine, and P ₁₆ and P ₁₇ are jumped to P ₁₈ . Further, when ΔS <So in P ₁₅ , the acceleration of the vehicle may be low, which is similar to the judgment that it can be sufficiently dealt with by the operation such as pumping loss of intake air regardless of fuel injection (recovery).
Jump on P ₁₆ and P ₁₇ to P ₁₈ . At P ₁₈ , the speed increasing valve of the actuator 19 is operated according to the magnitude of the vehicle speed difference ΔS this time. This is performed by opening the vacuum valve 33 in the actuator 19 according to the magnitude of ΔS. When performing speed increasing with P ₁₄ and later flows thus it is broadly divided into three streams, the output adjustment is performed in accordance with the state.

(B) When going through P ₁₄ → P ₁₅ → P ₁₆ .

At this time, the holding function of the holding circuit 21 is held, and the actuator 19 is operated to increase the opening of the throttle valve in accordance with the magnitude of ΔS. That is, in the fuel cut state, the throttle valve opening is adjusted to increase. Since the fuel cut state is set, the engine output due to the combustion pressure does not increase even if the throttle valve opening is increased.

However, since the amount of intake air is increased and the force to vacuum the inside of the cylinder and the pumping loss are reduced, the driving force of the engine that tries to prevent the inertial running force of the vehicle becomes small, but becomes small. This can be considered as an increase in vehicle speed as a result. That is, the actuator
If the opening of the throttle valve is increased by 19, the vehicle speed will increase.

Such vehicle speed increase processing is not based on reinjection (recovery) of fuel as in the past. Therefore, the speed-up shock is remarkably reduced in spite of the process of increasing the vehicle speed, and in reality, the occupant hardly feels the acceleration feeling, and the riding comfort is remarkably improved.

(B) When going through P ₁₄ ---> ₁₈ .

At this time, the processing of HF = 0 was performed in the previous routine, and a large amount of vehicle speed increase is required. Therefore, when the throttle valve is opened by the actuator 19, recovery is performed by releasing the function of the holding circuit 21, the vehicle is accelerated by the combustion pressure, and approaches the target value. This is because the acceleration amount is limited only by the operation such as the pumping loss of the intake air.

However, in the range of ΔS <ΔSo, at least the vehicle speed is not adjusted by the recovery, so that the acceleration shock is reduced as compared with the conventional case.

(C) When going through P ₁₄ → P ₁₅ → P ₁₆ → P ₁₇ → P ₁₈ .

At this time, although HF = 1 initially, ΔS is a predetermined amount Δ
So it is more than So, and HF =
The holding function of the holding circuit 21 is released as 0, and the process of P ₁₈ is performed in the same manner as (b) above. Therefore, the speed is increased by using the recovery together, and if the target value is not reached with this speed increase amount, the recovery speed is further increased in the next routine.

On the other hand, when the vehicle speed difference ΔS is negative in step P ₁₃ , that is, when the actual vehicle speed is higher than the target, the deceleration valve of the actuator 19 is operated in P ₁₉ according to the magnitude of the current vehicle speed difference ΔS. This is the belt valve in actuator 19.
32 is opened according to the value of ΔS.

Therefore, at this time, the opening of the throttle valve becomes smaller according to the value of ΔS. Contrary to the above case, when the throttle valve opening becomes smaller, the force to vacuum the cylinder and the pumping loss increase while the fuel is being cut. The driving force is increased, and this is considered to result in a reduction in engine output. That is, if the opening of the throttle valve is reduced by the actuator 19, the engine output will decrease.

As described above, in this embodiment, when the fuel cut is performed in the constant speed traveling state, the constant speed traveling flag CF is first set and the holding flag HF is set. By setting the holding flag HF, even if the throttle valve leaves the idle position, the holding circuit 21 creates a state in which it is in the pseudo idle position. Then, under this pseudo condition, the throttle valve is opened / closed to such an extent that the friction torque of the engine is simply adjusted, and constant speed traveling control is performed. Therefore, even if the throttle valve switch 5 is actually turned off, the throttle valve switch O
An N-equivalent signal is sent to the microcomputer 7 and fuel injection is not restarted. Therefore, although the throttle valve is gently opened and closed as in the conventional case, unlike the state where the difference from the target is not taken into consideration, it is possible to significantly soften the shock of the vehicle and improve the riding comfort.

When the difference between the target vehicle speed and the actual vehicle speed is positive and is larger than a predetermined value, the above-mentioned pseudo condition is canceled and the engine output is rapidly increased by the recovery. As a result, the difference from the target is properly taken into consideration, and the constant speed running is effectively performed. Therefore, the acceleration shock at the time of recovering from the fuel cut state can be reduced while maintaining the constant speed running, and the riding comfort of the occupant can be significantly improved.

(II) When running at a constant speed with fuel injection.

At this time, when N <Nc at P ₉ or when the throttle switch 5 is off at P ₁₀ , neither of the fuel cut conditions is satisfied. Therefore, the function of the holding circuit 21 is not held because the flow flows by jumping P ₁₁ . Therefore, according to the movement of the throttle valve, the engine output is adjusted by the combustion pressure in the subsequent steps.

FIG. 5 shows a subroutine for calculating the engine speed N (JO
B2), and this routine is executed in response to the input of a pulse that occurs once for each reference crank angle.

First, measure the input period of the generated pulses corresponding to the reference crank angle from the crank angle sensor 4 at P _21, and inverse calculation of the period data in P ₂₂ calculates the engine speed N.

FIG. 6 is a subroutine (JOB3) for releasing the constant speed traveling control associated with the accelerator operation, and this routine is executed once every 20 ms, for example.

First, constant-speed running release it is determined whether or not instructed by the P _31. This is performed by judging whether or not the brake pedal is depressed by the signal from the brake switch 16. When the brake pedal is depressed, it is determined that release of the cruise control is commanded, the process proceeds to P ₃₃ to reset the constant-speed travel flag CF in P _32, the P ₃₂ when the pedal is not depressed Jump to P ₃₃ . Whether the stroke of the accelerator pedal is changed to a predetermined value or more by the signal from the P ₃₃ in the accelerator switch 17, i.e., it determines whether the accelerator pedal is depressed. Hold flag HF at P ₃₄ it is determined that when the accelerator pedal is depressed there is an acceleration request
Check. When the HF = 1 resets the hold flag HF at P ₃₆ releases the pseudo function of the holding circuit 21 at P _33. When HF = 0 on P _34, it returns as it is.

When an acceleration request is made by depressing the accelerator pedal by executing this routine, the operating function of the holding circuit 21 is immediately released and the engine output is adjusted by opening and closing the original throttle valve to increase the engine output in accordance with the acceleration request. Is planned.

(Effect) According to the present invention, it is possible to avoid excessive control of the engine output when the difference between the target vehicle speed and the actual vehicle speed is small, and it is possible to reduce the shock and improve the riding comfort.

[Brief description of drawings]

FIG. 1 is a basic conceptual diagram of the present invention, and FIGS. 2 to 7 are diagrams showing an embodiment of a vehicle constant speed traveling device according to the present invention.
FIG. 4 is an overall configuration diagram thereof, FIG. 3 is a diagram showing a connection state of the holding circuit, FIG. 4 is a detailed sectional view of the actuator, FIG. 5 is a flow chart showing a program for the constant speed traveling control, and FIG. FIG. 6 is a flow chart showing a sub-program for measuring the engine speed, and FIG. 7 is a flow chart showing a sub-program for releasing the holding means in the accelerator depressed state. 6 ... Injector (fuel supply means), 7 ... Microcomputer (supply amount calculation means, fuel cut command means), 8 ... Operating state detection means, 18 ... Command switch (target setting means), 19 ... Actuator (Output adjusting means), 20 ... Microcomputer (calculating means, vehicle speed control means), 21 ... Holding circuit (holding means), 22 ... Running state detecting means.

Claims (1)

[Claims] 1. A driving state detecting means for detecting an operating state of an engine; b) a traveling state detecting means for detecting a traveling state of a vehicle; and c) a fuel cut when the engine is in a predetermined deceleration operating range. Fuel cut commanding means for instructing, d) target setting means for instructing constant speed traveling control to set a target vehicle speed, e) calculating means for calculating a difference between the target vehicle speed and the actual vehicle speed, and f) engine A fuel supply amount calculation means for calculating a fuel supply amount according to an operating state, outputting a supply signal, and, when a fuel cut is commanded, a supply amount calculation means for stopping the output of the supply signal, and g) supplying fuel to an engine based on the supply signal. The fuel supply means to be supplied, and h) When the fuel cut command and the constant speed travel command are both issued and the difference between the actual vehicle speed and the target vehicle speed is smaller than a predetermined value, the engine is in the operating state. Regardless, the fuel cut command is held, while the holding means releases the holding of the fuel cut command when the difference between the actual vehicle speed and the target vehicle speed becomes larger than a predetermined value. I) Both the fuel cut command and the constant speed running command When the difference between the actual vehicle speed and the target vehicle speed is smaller than a predetermined value, the control value that controls the engine output by adjusting the air flow rate to the cylinder is calculated, while the actual vehicle speed and the target vehicle speed are calculated. A vehicle speed control means for calculating a control value for controlling the engine output by adjusting the fuel supply amount when the difference between the vehicle speed control means and the fuel supply amount is larger than a predetermined value; A constant-speed traveling device for a vehicle, comprising: