JP2007192098A - Engine control device and engine control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate the adjustment of vehicle speed even if idling conditions are satisfied and reduce useless energy consumption. <P>SOLUTION: In this engine control device, auto cruise control is performed instead of rotation speed control basically based on engine rotation speed even under a condition where a vehicle travels by creep under an idling condition owing to a traffic jam or the like. Consequently, fine adjustment of vehicle speed is facilitated even if the vehicle travels in a low speed range. As a result, brake control basically does not accompany or is inhibited, and useless energy consumption while the vehicle travels at low speed can be reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an engine control apparatus and an engine control method that include at least one of a function of causing a vehicle to travel at a constant speed at a set vehicle speed and a function of causing a vehicle to follow a vehicle at an inter-vehicle distance set to a preceding vehicle.

  2. Description of the Related Art Conventionally, from the viewpoint of reducing driver's operation burden and driving safety of a vehicle, a vehicle control device having an auto-cruise control function that automatically controls a vehicle regardless of an operation amount of an accelerator pedal or the like by a driver. Are known. This vehicle control device executes vehicle speed control for causing the vehicle to travel at a constant speed at a speed set by the driver, and inter-vehicle control for causing the vehicle to follow the preceding vehicle at a set inter-vehicle distance (see, for example, Patent Document 1).

Such auto-cruise control is transitioned from normal control, that is, control that causes the vehicle to accelerate / decelerate based on the accelerator opening, etc., by operating a cruise switch provided in the passenger compartment by the driver. By operating the cruise switch, the driver can switch between auto-cruise control and normal control, and can increase or decrease the set vehicle speed during auto-cruise control. The vehicle control device calculates a driving force for realizing the vehicle speed control based on the set vehicle speed and various control amounts for realizing the driving force, and includes an engine, a transmission, and a brake based on the control amount. Control various objects. Further, when the preceding vehicle is traveling at a speed lower than the set vehicle speed, the vehicle control device switches from the vehicle speed control to the inter-vehicle distance control in order to prevent a rear-end collision.
Japanese Patent Laid-Open No. 11-254994

  Incidentally, the amount of air flowing into the engine is one of the control amounts that influence the driving force of such automatic cruise control. The amount of air flowing into the engine is determined based on the minimum amount of air that is secured to prevent engine stall during idling (hereinafter also referred to as “inflow air amount by ISC control”) and other required throttle openings. It is determined by the amount of air.

In the conventional auto cruise control, the vehicle speed control is performed by adding the inflow air amount based on each required throttle opening to the inflow air amount by the ISC control.
FIG. 7 is a schematic diagram showing a configuration example around the throttle valve of the intake system of the engine. (A) shows a configuration example in which an idle speed control valve (hereinafter referred to as “ISCV”) is provided, and (B) shows a configuration example in which no ISCV is provided.

  As shown in FIG. 2A, there is an engine in which a bypass passage 103 is formed in the intake pipe 101 so as to bypass the throttle valve 102 and an ISCV 104 is arranged in the bypass passage 103. During idling, the engine speed is adjusted by closing the throttle valve 102 to control the opening of the ISCV 104 and adjusting the amount of air flowing into the engine.

  Further, as shown in FIG. 5B, such an ISCV is not provided in a recent engine, and an electronic device that finely adjusts the opening of the throttle valve 102 to adjust the amount of air flowing into the engine. There is also a throttle.

  In any case, for example, when the vehicle is running at low speed in an idling state, such as when there is a traffic jam, and the inflow air amount based on each other required throttle opening is zero, a predetermined idling speed is set to prevent engine stall. (For example, about 700 rpm) must be maintained, and such inflow air amount control is performed. For this reason, in such a low speed region of the vehicle, the auto cruise control is not basically performed, and the inflow air amount is controlled so that the engine speed approaches the target speed. That is, in such a low speed range, the vehicle speed itself is not controlled, so that there is a problem that fine adjustment of the vehicle speed is difficult.

  On the other hand, a method for adjusting the deceleration, stop, and start of the vehicle by executing auto-cruise control even in the idling state and actively controlling the brake pressure has been devised. However, decelerating the vehicle with the brake converts the driving energy of the vehicle into heat energy, and therefore, there is a problem that wasteful energy is consumed and wear of the brake pad is promoted.

  The present invention has been made in view of these points, and an object of the present invention is to facilitate adjustment of the vehicle speed even when an idle condition is established in engine control, and to reduce wasteful energy consumption.

  In the present invention, in order to solve the above problem, idle speed control means for controlling the inflow air amount based on the deviation between the actual engine speed and the target speed when the idle control condition is satisfied, the current vehicle speed and the target And a constant speed travel control means for controlling the amount of inflow air based on a deviation from the vehicle speed. The engine speed control means when the idle control condition is satisfied during the constant speed travel control by the constant speed travel control means. An engine control device is provided, wherein the number control means controls the inflow air amount based on a deviation between the current vehicle speed and the target vehicle speed.

  In such an engine control device, control of the inflow air amount for vehicle speed control is actively performed even when the idle control condition is satisfied. For example, when an auto-cruise function is provided, a control range in which the required throttle opening in normal control corresponds to zero, i.e., in the related art, a speed tracking control based on the engine speed is performed even during the auto-cruise control. Even in a region where the vehicle speed control based on the auto-cruise control is basically not performed, the inflow air amount control for the vehicle speed control is actively performed.

  Further, in the present invention, the idle speed control step for controlling the inflow air amount based on the deviation between the actual engine speed and the target speed when the idle control condition is satisfied, and the deviation between the current vehicle speed and the target vehicle speed. A constant speed traveling control step for controlling the inflow air amount based on the current vehicle speed and the target vehicle speed when the idle control condition is satisfied during the constant speed traveling control by the constant speed traveling control step. An engine control method is provided that controls the amount of inflow air based on the deviation.

  In such an engine control method, control of the inflow air amount for vehicle speed control is actively performed even when the idle control condition is satisfied. For example, when the auto-cruise function is provided, the control of the inflow air amount for the vehicle speed control is actively performed even in the control region where the required throttle opening in the normal control corresponds to zero.

  According to the engine control device and the engine control method of the present invention, even if the idle control condition is satisfied, the control of the inflow air amount for the vehicle speed control is positively performed, and basically the brake control is not accompanied. For this reason, it is possible to reduce wasteful energy consumption when the vehicle travels at a low speed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a vehicle control system to which the engine control device of the present embodiment is applied.
Each control object of this vehicle control system is controlled by an electronic control unit (Electronic Control Unit: hereinafter referred to as “ECU”) mainly composed of a microcomputer. That is, engine control and shift control are performed centering on an engine control ECU (hereinafter referred to as “engine ECU”) 1, and vehicle distance control is performed centering on an inter-vehicle control ECU (hereinafter referred to as “vehicle distance control ECU”) 2. In addition, brake control, traction control, and the like are performed by an ECU 3 for an undercarriage such as a brake (hereinafter referred to as “skid ECU”) 3.

  Each ECU of the present embodiment is configured as a control unit independent from each other, and is connected to be communicable with each other by an in-vehicle LAN 4 adopting a CAN (Controller Area Network) communication protocol. It is good also as a structure provided in the inside. In addition to the ECUs, a steering sensor 6 that detects a steering operation angle by a driver and a yaw rate sensor 7 that detects a yaw rate of the vehicle are connected to the in-vehicle LAN 4, and detection signals from both sensors are received. Output to each ECU.

  The engine ECU 1 includes an accelerator opening sensor 11 that detects the amount of depression of the accelerator pedal, an engine speed sensor 12 that detects the engine speed, a vehicle speed sensor 13 that detects the vehicle speed from the rotation of the vehicle drive shaft, and an intake air amount. Sensors and switches such as an air flow meter 14 for detecting, a shift position sensor 15 for detecting the current shift position, and a cruise control switch 16 for operating auto cruise control settings are connected, and output signals of the sensors and switches are input. Has been.

  The cruise control switch 16 includes a cruise main switch for starting the auto cruise control, a cruise cancel switch for ending the cruise control, a cruise vehicle speed set switch for setting the target vehicle speed, and a predetermined amount of the target vehicle speed. A cruise acceleration request switch for increasing the speed, a cruise deceleration request switch for decelerating the target vehicle speed by a predetermined amount, and the like can be set in the vehicle interior.

  The engine ECU 1 includes an injector 21 provided for each cylinder of the engine for injecting fuel, an igniter 22 for generating a high voltage for ignition, and a throttle drive motor for driving and controlling an electronic throttle provided in an intake pipe of the engine. 23. Engine control such as a shift solenoid 24 for driving and controlling the automatic transmission, and a torque converter hydraulic circuit 25 for controlling a coupling force of a torque converter that is disposed between the engine and the automatic transmission and smoothly transmits the driving force. For this purpose, various actuators are connected, and various control command signals are output to the various actuators.

  The inter-vehicle control ECU 2 acquires information such as the current vehicle speed (current vehicle speed), the steering operation angle, and the yaw rate through communication, estimates the curvature radius of the curve while the vehicle is traveling, and performs arithmetic processing for inter-vehicle control. ing.

  The radar sensor 31 includes a distance sensor such as a laser radar or a millimeter wave radar and a microcomputer for calculation processing. The radar sensor 31 has a relative speed with respect to a preceding vehicle detected by the distance sensor, a current vehicle speed acquired from the inter-vehicle control ECU 2 and an estimated curve radius. Based on the above, a relative position with respect to the preceding vehicle, an inter-vehicle distance, and the like are calculated and transmitted to the inter-vehicle control ECU 2 as preceding vehicle information.

  The inter-vehicle control ECU 2 calculates the target inter-vehicle distance from the preceding vehicle based on the preceding vehicle information received from the radar sensor 31 and the input information from the inter-vehicle distance switching switch 32. Then, the inter-vehicle control ECU 2 transmits information such as a target acceleration / deceleration and a deceleration gradient to the engine ECU 1 as a control amount necessary for realizing the target inter-vehicle distance. Further, when the inter-vehicle control ECU 2 determines that the inter-vehicle distance is short and there is a possibility of a rear-end collision, the inter-vehicle control ECU 2 transmits a brake request, an alarm request, or the like to the skid ECU 3.

  When the skid ECU 3 receives the brake request, the skid ECU 3 controls the brake hydraulic circuit 33 to adjust the brake pressure. In addition, the skid ECU 3 sounds an alarm buzzer 35 based on an alarm request or the like, detects that the brake pedal has been depressed and turns on the stop lamp 34, and if a brake abnormality is detected, A signal indicating that is transmitted to the engine ECU 1.

  Next, the engine control method of the present embodiment will be described. This vehicle control process is performed when the vehicle is traveling in an idle state in a predetermined low speed range (for example, the vehicle speed is 5 km / h to 35 km / h) close to creep traveling due to traffic jams, for example, a request in normal control. Since there is a feature in the vehicle control in the control region in which the throttle opening corresponds to zero, the description will focus on that portion.

  2 to 4 are functional block diagrams illustrating an example of a vehicle control process that is executed mainly by the engine ECU when the vehicle travels at a low speed. FIG. 2 shows a vehicle control process during normal control in which auto-cruise control is not performed. 3 and 4 show a vehicle control process during auto-cruise control.

First, the case of normal control that has not transitioned to auto-cruise control by operating the cruise control switch 16 will be described.
As shown in FIG. 2, when the vehicle enters an idling state in which the vehicle creeps due to a traffic jam or the like, the target value calculation unit 41 creates a control map that is set in advance based on information on electrical loads such as the current shift position and on-vehicle air conditioner With reference to the target engine speed, a target engine speed that is a target value of the engine speed is calculated.

Subsequently, the deviation calculating unit 42 calculates the deviation between the actual engine speed, which is the current engine speed, and the target engine speed.
Then, the feedback correction amount calculation unit 43 calculates a feedback correction amount that is an inflow air amount for bringing the actual rotational speed close to the target rotational speed.

  In parallel with this calculation, the flow rate learning value calculation unit 44 sequentially learns the feedback correction amount, and stores / updates it as a flow rate learning value in a non-volatile memory such as a standby RAM. Since the learning value of the flow rate is maintained even when the engine is stopped, the flow rate learning value is immediately read and used for auto-cruise control when the engine is driven next time, and the inflow air amount can be brought close to the target flow rate quickly.

  In addition, various correction amount calculation units 45 refer to a control map set in advance based on engine torque variation factors such as the purge control state accompanying the evaporated fuel processing, the driving state of the in-vehicle air conditioner, and the current shift position. Various correction amounts are calculated for controlling the inflow air amount.

Subsequently, the target flow rate calculation unit 46 adds the feedback correction amount, the flow rate learning value, and various correction amounts to calculate a target flow rate that is an inflow air amount as a target value.
Then, the control amount calculation unit 47 calculates a control amount for realizing this target flow rate. That is, the throttle opening of the electronic throttle is calculated, and a control signal for realizing it is output to the throttle drive motor 23.

Next, a vehicle control process in the case where the cruise control switch 16 is changed to the auto cruise control will be described.
As shown in FIG. 3, when the vehicle enters an idling state in which the vehicle creeps due to a traffic jam or the like, the target value calculation unit 41 refers to information on the current cruise control switch 16 and a control map set in advance based on the current vehicle speed. The target vehicle speed is calculated.

Subsequently, the deviation calculating unit 42 calculates the deviation between the current vehicle speed and the target vehicle speed.
Then, the feedback correction amount calculation unit 43 calculates a feedback correction amount that is an inflow air amount for bringing the current vehicle speed close to the target vehicle speed.

  In parallel with this calculation, the various correction amount calculation unit 45 refers to a control map set in advance based on various engine torque fluctuation factors such as the purge control state, the driving state of the in-vehicle air conditioner, and the current shift position. Then, various correction amounts for controlling the inflow air amount are calculated. Here, the calculation of the flow rate learning value by the flow rate learning value calculation unit 44 is not performed. This is to prevent the flow rate learning value from interfering with vehicle speed control.

Subsequently, the target flow rate calculation unit 46 adds the feedback correction amount and various correction amounts to calculate a target flow rate that is an inflow air amount as a target value.
Then, the control amount calculation unit 47 calculates a control amount for realizing this target flow rate. That is, the throttle opening of the electronic throttle is calculated, and a control signal for realizing it is output to the throttle drive motor 23.

  As described above, vehicle speed control by auto-cruise control is performed even when the vehicle is in an idling state, but in this embodiment, in order to prevent a collision based on the distance between the host vehicle and the preceding vehicle. The inter-vehicle distance control is also executed.

  That is, as shown in FIG. 4, the target value calculation unit 41 includes the actual inter-vehicle distance that is the current inter-vehicle distance between the host vehicle and the preceding vehicle from the inter-vehicle control ECU 2 in addition to the current cruise control switch 16 information and the current vehicle speed. Get information about. When the actual inter-vehicle distance is equal to or less than a reference value set in advance according to the current vehicle speed to prevent a rear-end collision, the vehicle speed control is switched to the inter-vehicle control. That is, the target value calculation unit 41 refers to a control map set in advance based on the current cruise control switch 16 information, the current vehicle speed, and the actual inter-vehicle distance, and calculates the target inter-vehicle distance.

Subsequently, the deviation calculating unit 42 calculates the deviation between the actual inter-vehicle distance and the target inter-vehicle distance.
Then, the feedback correction amount calculation unit 43 calculates a feedback correction amount that is an inflow air amount for causing the vehicle to follow the preceding vehicle by bringing the actual inter-vehicle distance closer to the target inter-vehicle distance.

In parallel with this calculation, the various correction amount calculation unit 45 calculates various correction amounts for the inflow air amount control based on various fluctuation elements of the engine torque, as described above.
Subsequently, the target flow rate calculation unit 46 adds the feedback correction amount and various correction amounts to calculate a target flow rate that is an inflow air amount as a target value.

  Then, the control amount calculation unit 47 calculates a control amount for realizing this target flow rate. That is, the throttle opening of the electronic throttle is calculated, and a control signal for realizing it is output to the throttle drive motor 23.

  As described above, in the engine control apparatus of the present embodiment, even when the vehicle is creeping in an idling state due to traffic jams or the like, basically, the engine speed control based on the engine speed is not used. Without auto-cruise control. This facilitates fine adjustment of the vehicle speed even when the vehicle is traveling in a low speed range. As a result, the brake control is basically not performed or the brake control is suppressed, and it is possible to reduce wasteful energy consumption when the vehicle travels at a low speed.

  Although not described in the above embodiment, if the intake air amount is decreased in the low speed range, there is a risk of causing engine stall or drivability deterioration due to misfire or the like. A lower limit guard may be provided for the flow rate. That is, when the calculated target flow rate falls below a lower limit guard set in advance to prevent engine stall or drivability, the target flow rate calculation unit 46 keeps the target flow rate at this lower limit guard. May be.

  However, if the state where the lower limit guard continues to be maintained continues, the vehicle speed may not be appropriately reduced by adjusting the intake air amount. For this reason, in such a case, safety may be prioritized, and control elements other than the intake air amount may be controlled to forcibly decelerate.

  5 and 6 are explanatory diagrams showing a control map used for vehicle control according to the modification. In FIG. 5, the horizontal axis represents the deviation in the inter-vehicle distance, and the vertical axis represents the magnitude of the brake pressure. In FIG. 6, the horizontal axis represents the deviation in the inter-vehicle distance, and the vertical axis represents the magnitude of the coupling force of the torque converter.

  That is, when the target flow rate is maintained in the lower limit guard by the target flow rate calculation unit 46 for a predetermined time, a brake request is transmitted from the engine ECU 1 to the skid ECU 3, and the brake pressure is adjusted by brake control to adjust the vehicle speed. You may make it decelerate appropriately. In this case, as shown in FIG. 5, the control is performed so that the brake pressure increases as the deviation between the actual inter-vehicle distance and the target inter-vehicle distance increases.

  Alternatively, when the target flow rate is held by the lower limit guard by the target flow rate calculation unit 46 for a predetermined time, the torque converter hydraulic circuit 25 is controlled to adjust the engagement force of the lock-up clutch, and the vehicle speed is adjusted. You may make it decelerate appropriately. In this case, as shown in FIG. 6, the torque converter is controlled such that the engaging force decreases as the deviation between the actual inter-vehicle distance and the target inter-vehicle distance increases.

In addition, since the engine stall is likely to occur as the electric load of the vehicle increases, the lower limit guard may be adjusted to increase as the electric load increases.
Furthermore, in the setting of the target flow rate by the vehicle speed control or the inter-vehicle control described above, it is also assumed that the engine speed rapidly decreases and engine stall occurs. For this reason, when the time change of the reduction amount of the engine speed exceeds a predetermined value, the process may return to the speed tracking control shown in FIG. In this case, the target value calculation unit 41 sets a target rotation number for keeping the engine rotation number at a predetermined value or more as the target value, and the feedback correction amount calculation unit 43 sets the target rotation number and the actual rotation number. The feedback correction amount is calculated from the deviation.

  In the above embodiment, the engine intake system is not provided with the ISCV and the throttle opening degree of the electronic throttle is controlled. However, the same vehicle control is applied to the vehicle equipped with the ISCV. it can. In that case, the control amount calculation unit 47 calculates the duty ratio of the supply current for determining the valve opening of the ISCV.

  Moreover, in the said embodiment, as shown in FIG. 4, although the example which switches from vehicle speed control to inter-vehicle distance control based on the inter-vehicle distance of the own vehicle and a front vehicle was shown, the target vehicle speed is zero or its vicinity If the vehicle speed control is continued when the vehicle enters a predetermined extremely low speed range, the traveling performance of the vehicle is deteriorated. In such a case, the vehicle speed control is switched to the inter-vehicle control, the target value calculation unit 41 sets a predetermined target inter-vehicle distance as the target value, and the feedback correction amount calculation unit 43 determines that the target inter-vehicle distance and the actual inter-vehicle distance are The feedback correction amount may be calculated from the deviation.

1 is a block diagram illustrating a schematic configuration of a vehicle control system to which an engine control device of an embodiment is applied. It is a functional block diagram showing an example of the vehicle control process which an engine ECU performs centering on low speed driving | running | working of a vehicle. It is a functional block diagram showing an example of a vehicle control process that is executed mainly by an engine ECU when the vehicle is traveling at low speed. It is a functional block diagram showing an example of the vehicle control process which an engine ECU performs centering on low speed driving | running | working of a vehicle. It is explanatory drawing showing the control map used for the vehicle control which concerns on a modification. It is explanatory drawing showing the control map used for the vehicle control which concerns on a modification. It is the schematic showing the example of a structure of the throttle valve periphery of an engine intake system.

Explanation of symbols

1 Engine ECU
2 Inter-vehicle control ECU
3 Skid ECU
41 Target Value Calculation Unit 42 Deviation Calculation Unit 43 Feedback Correction Amount Calculation Unit 44 Flow Rate Learning Value Calculation Unit 45 Various Correction Amount Calculation Units 46 Target Flow Rate Calculation Unit 47 Control Amount Calculation Unit

Claims (13)

Idle speed control means for controlling the inflow air amount based on the deviation between the actual engine speed and the target engine speed when the idle control condition is satisfied;
Constant speed traveling control means for controlling the inflow air amount based on the deviation between the current vehicle speed and the target vehicle speed;
In an engine control device having
The idle speed control means controls the inflow air amount based on a deviation between the current vehicle speed and the target vehicle speed when the idle control condition is satisfied during the constant speed running control by the constant speed running control means. Engine control device. It has an auto cruise function,
The idle speed control means and the constant speed travel control means are respectively
A target value calculation unit that calculates a target value that is a control target based on the state of the vehicle;
A correction amount calculation unit that calculates a feedback correction amount from a deviation between the target value and a current value that is an actual state amount;
A target flow rate calculation unit that calculates a target flow rate that is an inflow air amount required for the engine based on the feedback correction amount;
A control amount calculation unit that calculates a control amount for realizing the target flow rate and outputs the control amount to an actuator for adjusting the inflow air; and
With
In the control region in which the required throttle opening in the normal control corresponds to zero as the idle control condition during the auto cruise control, the idle speed control means
A predetermined target vehicle speed is set as the target value by the target value calculation unit,
Calculating the feedback correction amount from a deviation between the target vehicle speed and the current vehicle speed by the correction amount calculation unit;
The engine control apparatus according to claim 1. As the auto-cruise function, including an inter-vehicle control function for controlling the vehicle to follow the vehicle at a set inter-vehicle distance,
During the auto-cruise control, when the required throttle opening in the normal control is in a control region corresponding to zero, and the inter-vehicle distance with the preceding vehicle is a predetermined value or less,
The idle speed control means includes
A predetermined target inter-vehicle distance is set as the target value by the target value calculation unit,
Calculating the feedback correction amount from the deviation between the target inter-vehicle distance and the actual inter-vehicle distance by the correction amount calculating unit;
The engine control apparatus according to claim 2. As the auto-cruise function, including an inter-vehicle control function for controlling the vehicle to follow the vehicle at a set inter-vehicle distance,
When the target vehicle speed enters a predetermined extremely low speed range of zero or in the vicinity thereof,
The idle speed control means includes
A predetermined target inter-vehicle distance is set as the target value by the target value calculation unit,
Calculating the feedback correction amount from the deviation between the target inter-vehicle distance and the actual inter-vehicle distance by the correction amount calculating unit;
The engine control apparatus according to claim 2.   The idle rotational speed control means sets a lower limit guard capable of preventing at least misfiring to the target flow rate by the target flow rate calculation unit, and when the target flow rate falls below the lower limit guard, the target flow rate is set to the lower limit value. The engine control device according to claim 2, wherein the engine control device is held by a guard. A brake pressure control unit for controlling the brake pressure of the vehicle;
The brake pressure control unit controls the brake pressure to be increased to decrease the vehicle speed when the state where the target flow rate is held by the lower limit guard continues for a predetermined time. 5. The engine control device according to 5. As the auto-cruise function, including an inter-vehicle control function for controlling the vehicle to follow the vehicle at a set inter-vehicle distance,
The engine control device according to claim 6, wherein the brake pressure control unit controls the brake pressure to increase as the deviation between the target inter-vehicle distance and the actual inter-vehicle distance in the inter-vehicle control function increases. A hydraulic control unit that controls a hydraulic pressure for adjusting an engagement force of a torque converter provided between the engine of the vehicle and the automatic transmission;
The hydraulic pressure control unit controls the hydraulic pressure so as to reduce the engagement force of the torque converter when the state in which the target flow rate is held by the lower limit guard continues for a predetermined time, and reduces the vehicle speed. The engine control apparatus according to claim 5, wherein As the auto-cruise function, including an inter-vehicle control function for controlling the vehicle to follow the vehicle at a set inter-vehicle distance,
9. The engine control according to claim 8, wherein the hydraulic control unit controls the engagement force of the torque converter to be smaller as the deviation between the target inter-vehicle distance and the actual inter-vehicle distance in the inter-vehicle distance control function increases. apparatus.   The engine control apparatus according to claim 5, wherein the target flow rate calculation unit adjusts the lower limit guard so as to increase as the electric load of the vehicle increases.   When the required throttle opening in the normal control is in a control region corresponding to zero during the auto cruise control, the idle speed control means is calculated by the correction amount calculation unit by the target flow rate calculation unit. The engine control apparatus according to claim 2, wherein learning based on the feedback correction amount is prohibited. When the time change of the decrease amount of the engine speed exceeds a predetermined value during the execution of the auto-cruise control in the control region where the required throttle opening in the normal control corresponds to zero,
The idle speed control means includes
The target value calculation unit sets a target speed for keeping the engine speed at a predetermined value or higher as the target value,
Calculating the feedback correction amount from the deviation between the target rotational speed and the actual rotational speed by the correction amount calculating section;
The engine control apparatus according to claim 2. An idle speed control step for controlling the inflow air amount based on the deviation between the actual engine speed and the target engine speed when the idle control condition is satisfied;
A constant speed traveling control step for controlling the inflow air amount based on a deviation between the current vehicle speed and the target vehicle speed;
In an engine control method comprising:
An engine control method for controlling an inflow air amount based on a deviation between the current vehicle speed and the target vehicle speed when the idle control condition is established during constant speed traveling control in the constant speed traveling control step.

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