JP6241297B2 - Active cruise control device - Google Patents

Description

  The present invention relates to an active cruise control device.

  In vehicles, particularly automobiles, active cruise control devices that follow and follow a preceding vehicle until the vehicle is stopped, that is, until the vehicle speed becomes zero, have been put into practical use. In this active cruise control device, the brake is automatically controlled and the engine output (engine torque) is automatically controlled.

  On the other hand, many recent vehicles perform an idle stop that automatically stops the engine when the vehicle is stopped. Also, a vehicle that automatically stops the engine by idle stop when the vehicle speed is equal to or lower than a predetermined vehicle speed greater than 0 even when the vehicle is not stopped has been put into practical use.

  Patent Document 1 discloses that an engine is automatically stopped when a stop state of the host vehicle is maintained and a predetermined idle stop condition is satisfied in a vehicle equipped with an active cruise control device. Japanese Patent Application Laid-Open No. H10-228561 discloses a device that automatically activates a parking brake when the engine is automatically stopped by an idle stop.

JP 2012-206593 A JP 2012-11969 A

By the way, it is conceivable to increase the chance of performing an idle stop when the follow-up vehicle is driven with respect to the preceding vehicle until the vehicle speed becomes 0 by the active cruise control device. For example, it is conceivable that the engine is automatically stopped by idle stop when the vehicle speed becomes equal to or lower than a predetermined vehicle speed (for example, 15 km / h) greater than zero. In the situation where the active cruise control device is operated, the driver usually does not perform the accelerator operation or the brake operation.

  However, if the engine is automatically stopped by idle stop because the vehicle speed is below the predetermined vehicle speed during the follow-up running by the active cruise control device, the distance between the preceding vehicle and the preceding vehicle due to sudden acceleration or sudden deceleration of the preceding vehicle Is likely to become too large or too small. For this reason, at present, in a vehicle equipped with an active cruise control device, the engine is not automatically stopped by an idle stop unless a stop is confirmed.

  The present invention has been made in view of the circumstances as described above, and an object of the present invention is to increase the chances of performing an idle stop while satisfying the followability to a preceding vehicle in a vehicle equipped with an active cruise control device. It is to provide an active cruise control device.

In order to achieve the above object, the following first solution is adopted in the present invention. That is, as described in claim 1,
An active cruise control device that follows the preceding vehicle until the vehicle speed becomes zero,
Stop detection means for detecting that the preceding vehicle is stopped;
An inter-vehicle distance detecting means for detecting an inter-vehicle distance from the preceding vehicle;
An inertial idle distance estimating means for estimating an inertial idle distance that is a distance that can be driven by inertia in a state where the engine is stopped and the brake is not operated;
When the active cruise control device is actuated to follow the preceding vehicle, the stop detection means detects the stop of the preceding vehicle, and the inertia free running distance estimated by the inertia free running distance estimation means Is an idle stop control means for automatically stopping the engine by an idle stop when the vehicle distance is less than or equal to the vehicle distance detected by the vehicle distance detection means,
It is supposed to be equipped with.

According to the above solution, the engine is automatically stopped by the idle stop when the inertial idle running distance capable of traveling by inertia is equal to or less than the inter-vehicle distance from the preceding vehicle. As a result, the engine can be automatically stopped at an earlier time compared to the case where the engine is automatically stopped by idle stop on the condition that the stop of the host vehicle is confirmed. Can be increased. In addition, if the preceding vehicle is stopped, the engine is automatically stopped by idle stop even if the vehicle is running. Therefore, even if the preceding vehicle starts, the engine is restarted with sufficient margin to follow the preceding vehicle. (To prevent the distance between vehicles from becoming too large). In addition, since the preceding vehicle is in a stopped state, there is no room for the preceding vehicle to suddenly decelerate and the inter-vehicle distance is prevented from becoming too small.

A preferred mode based on the first solution is as described in claim 2 in the claims. That is,
When the active cruise control device is actuated to follow the preceding vehicle, the stop detection means detects the stop of the preceding vehicle, and the inertia free running distance estimated by the inertia free running distance estimation means Is greater than the inter-vehicle distance detected by the inter-vehicle distance detecting means, the brake is automatically operated (corresponding to claim 2). In this case, the opportunity to automatically stop the engine by idle stop can be increased by effectively using the automatic brake.

In order to achieve the above object, the following second solution is adopted in the present invention. That is, as described in claim 3,
An active cruise control device that follows the preceding vehicle until the vehicle speed becomes zero,
Stop detection means for detecting that the preceding vehicle is stopped;
An inter-vehicle distance detecting means for detecting an inter-vehicle distance from the preceding vehicle;
An inertial idle distance estimating means for estimating an inertial idle distance that is a distance that can be driven by inertia in a state where the engine is stopped and the brake is not operated;
When the active cruise control device is actuated to follow the preceding vehicle, the stop detection means detects the stop of the preceding vehicle, and the inertia free running distance estimated by the inertia free running distance estimation means Idle stop control means for automatically stopping the engine by idle stop when the added distance obtained by adding a predetermined margin distance is equal to or less than the inter-vehicle distance detected by the inter-vehicle distance detecting means,
It is supposed to be equipped with. According to the above solution, the vehicle can be stopped in a state in which a marginal distance that is a preferable inter-vehicle distance is ensured with respect to the preceding vehicle while ensuring the same effect as the effect corresponding to claim 1. Can do.

A preferred mode based on the first solution technique and the second solution technique is as described in claim 4. That is,
It further comprises road surface condition detecting means for detecting the road surface condition,
The inertia idle running distance estimating means estimates the inertia empty running distance in consideration of the road surface condition detected by the road surface condition detecting means (corresponding to claim 4). In this case, it is preferable to estimate the inertia running distance more accurately and to automatically stop the engine by idle stop from the earliest possible timing. The road surface condition can include various parameters that affect the inertial running distance, such as road surface gradient, road surface μ, and distinction between good roads such as paved roads and unpaved bad roads. Parameters can be included.

  ADVANTAGE OF THE INVENTION According to this invention, the opportunity of performing the engine automatic stop by idle stop can be increased, satisfying the request | requirement of the followability with respect to a preceding vehicle.

The simplified side view which shows the state which starts the engine automatic stop by an idle stop in the process in which the own vehicle approaches the preceding vehicle which has stopped. FIG. 3 is a block diagram showing an example of a control system of the present invention. The flowchart which shows the example of control of this invention.

  In FIG. 1, V is the host vehicle, and VA is a preceding vehicle preceding the host vehicle V. The own vehicle V is equipped with an active cruise control device, and the engine output and the brake are automatically controlled so as to follow the preceding vehicle VA.

  In FIG. 1, the time when the preceding vehicle VA is stopped is shown, and the inter-vehicle distance between the host vehicle V and the preceding vehicle VA is shown as LV. In the state where the host vehicle V automatically stops the engine by idle stop and does not operate the automatic brake, an inertial idle running distance that is a distance that can be driven by inertia is indicated by a symbol LKK. Further, when the own vehicle V stops following the preceding vehicle VA that is stopped, the vehicle is set to be able to stop before the preceding vehicle VA by a predetermined margin distance (for example, 2 to 5 m). Yes.

  When the added value LX of the inertia idle running distance LKK and the marginal distance becomes equal to or less than the actual inter-vehicle distance LV, the host vehicle V runs with inertia, with the engine automatically stopped by an idle stop. During inertial running, the automatic brake is not activated. Due to this inertia traveling, the host vehicle V is stopped before the preceding vehicle VA by a margin distance. As described above, by performing the engine automatic stop by the idle stop while traveling, the opportunity to perform the idle stop is increased.

  FIG. 2 shows an example of a control system or the like that is configured in the host vehicle V and that automatically stops the engine by idling stop during traveling as described above. In the figure, U is a controller (control unit) configured using a microcomputer. This controller U performs active cruise control control for following the preceding vehicle and automatic engine stop control by idle stop, and is connected to various sensors and devices S1 to S8. In the embodiment, the active cruise control control can be performed over the entire vehicle speed range (range from the vehicle speed 0 to the maximum vehicle speed), but the vehicle speed from a predetermined vehicle speed (for example, 120 km / h) smaller than the maximum vehicle speed. It can be executed only in a limited vehicle speed range up to zero.

  S1 is an inter-vehicle distance detecting means for detecting an inter-vehicle distance LV with respect to the preceding vehicle VA, and is constituted by, for example, a millimeter wave radar. S2 is a camera as an imaging means for confirming the state of the preceding vehicle VA, and in particular detects a stop of the preceding vehicle VA. S3 is a vehicle speed sensor that detects the vehicle speed. S4 is a main switch of the active cruise control device. S5 is an inter-vehicle distance setting switch for changing the inter-vehicle distance with the preceding vehicle VA by manual operation when the main switch S4 is turned on and the active cruise control device is operated. The set inter-vehicle distance is set as the vehicle head time. That is, the vehicle head time is the time from when the preceding vehicle VA passes a certain position to when the host vehicle V passes a certain point. For example, when the vehicle head time is set to 2.5 seconds, it is 100 km / h. The distance between the vehicles is about 70 m when traveling. Even if the head time is the same, the smaller the vehicle speed of the host vehicle V, the more the vehicle follows the vehicle with a smaller inter-vehicle distance than the preceding vehicle VA. Note that the inter-vehicle distance during follow-up travel can always be automatically set so that it cannot be changed by manual operation.

  S6 is a brake control means (automatic brake means) for automatically operating the brake. S7 is a road surface condition detection means, and particularly detects a road surface condition that affects the inertial free running distance LKK. As a parameter to be detected, for example, road surface μ, road surface gradient, or road surface unevenness degree (good road, Arbitrary road distinction) or any combination thereof is detected. S8 is output control means for automatically controlling engine output (engine torque).

  FIG. 3 shows an example of control by the controller U. In the following description, Q indicates a step, and the main switch S4 is turned on so that the active cruise control device is operating.

  First, in Q1, signals from various sensors shown in FIG. 2 are read. Next, in Q2, the state of the preceding vehicle VA, particularly the state related to stopping is confirmed.

  In Q3, it is determined whether or not the preceding vehicle VA is stopped based on the confirmation result in Q2. The determination at Q3 can be determined, for example, that the preceding vehicle VA is stopped when the surrounding environment of the preceding vehicle VA is not changed in the image captured by the imaging unit S2. Further, when the vehicle speed of the host vehicle V detected by the vehicle speed sensor S3 and the relative speed obtained from the change in the inter-vehicle distance with respect to the preceding vehicle VA are the same, it can be determined that the preceding vehicle VA is stopped. . Note that the determination that the preceding vehicle VA is stopped can be made by an appropriate method other than the above.

  When the determination in Q3 is NO, the preceding vehicle VA is not stopped. At this time, in Q4, the engine output and the brake are automatically controlled so as to follow the preceding vehicle VA. Shifting can be automatically controlled for follow-up running.

  If YES in Q3, the inter-vehicle distance LV with the preceding vehicle VA is detected and stored in Q5 (stored in the storage means of the controller U). Next, at Q6, the inertia free running distance LKK is estimated and stored. In estimating the inertia free running distance LKK, for example, the inertia free running distance corresponding to the vehicle speed is created and stored in advance as a basic value, and this basic value is corrected according to the road surface condition detected by the road surface condition detecting means. This can be done. For example, the inertial running distance is corrected to a small (short) value on an uphill road, corrected to a large value on a downhill road, corrected to a small value on a rough road with severe unevenness, and inertial sky when the road surface μ is small. The mileage is corrected to a large value. It is also possible to estimate the running resistance of the road surface from the latest running situation of the host vehicle V and correct the basic value with the estimated road resistance. Note that the above-described method for estimating the inertial running distance is merely an example, and it is needless to say that other estimation methods may be used.

  After Q6, in Q7, the above-described margin distance is added to the inertial idle running distance LKK estimated in Q6 to obtain an added value LX.

  After Q7, at Q8, it is determined whether or not the added value LX is equal to or less than the actual inter-vehicle distance LV. If the determination in Q8 is NO, since the vehicle cannot stop at the stop position of the preceding vehicle VA even if the vehicle travels as it is due to inertia, the brake is automatically operated (deceleration) in Q9.

  After passing through Q9, it will eventually become YES in the determination of Q8, and at this time, in Q10, the engine is automatically stopped for idling stop. As a result, the host vehicle V is stopped at a position away from the preceding vehicle VA by a margin distance.

  Although the embodiments have been described above, the present invention is not limited to the embodiments, and appropriate modifications can be made within the scope of the claims. Without setting the allowance distance, the engine may be automatically stopped by idling when the estimated inertial running distance is equal to or less than the actual inter-vehicle distance. Of course, the object of the present invention is not limited to what is explicitly stated, but also implicitly includes providing what is substantially preferred or expressed as an advantage.

  The present invention is preferable in terms of improving fuel consumption by increasing the opportunity to automatically stop the engine by idle stop when traveling following the preceding vehicle.

V: own vehicle VA: preceding vehicle LV: inter-vehicle distance LKK: inertia free running distance LX: added value (inertial free running distance + margin distance)
U: Controller S1: Inter-vehicle distance detection means S2: Imaging means S3: Vehicle speed sensor S4: Main switch S5: Inter-vehicle distance setting switch S6: Brake control means S7: Road surface condition detection means S8: Engine output control means

Claims (4)

An active cruise control device that follows the preceding vehicle until the vehicle speed becomes zero,
Stop detection means for detecting that the preceding vehicle is stopped;
An inter-vehicle distance detecting means for detecting an inter-vehicle distance from the preceding vehicle;
An inertial idle distance estimating means for estimating an inertial idle distance that is a distance that can be driven by inertia in a state where the engine is stopped and the brake is not operated;
When the active cruise control device is actuated to follow the preceding vehicle, the stop detection means detects the stop of the preceding vehicle, and the inertia free running distance estimated by the inertia free running distance estimation means Is an idle stop control means for automatically stopping the engine by an idle stop when the vehicle distance is less than or equal to the vehicle distance detected by the vehicle distance detection means,
An active cruise control device characterized by comprising: In claim 1,
When the active cruise control device is actuated to follow the preceding vehicle, the stop detection means detects the stop of the preceding vehicle, and the inertia free running distance estimated by the inertia free running distance estimation means An active cruise control device, wherein the brake is automatically operated when the vehicle distance is larger than the vehicle distance detected by the vehicle distance detection means. An active cruise control device that follows the preceding vehicle until the vehicle speed becomes zero,
Stop detection means for detecting that the preceding vehicle is stopped;
An inter-vehicle distance detecting means for detecting an inter-vehicle distance from the preceding vehicle;
An inertial idle distance estimating means for estimating an inertial idle distance that is a distance that can be driven by inertia in a state where the engine is stopped and the brake is not operated;
When the active cruise control device is actuated to follow the preceding vehicle, the stop detection means detects the stop of the preceding vehicle, and the inertia free running distance estimated by the inertia free running distance estimation means Idle stop control means for automatically stopping the engine by idle stop when the added distance obtained by adding a predetermined margin distance is equal to or less than the inter-vehicle distance detected by the inter-vehicle distance detecting means,
Active cruise control apparatus characterized in that it comprises. In any one of Claims 1 thru | or 3,
It further comprises road surface condition detecting means for detecting the road surface condition,
The inertial idle travel distance estimating means estimates the inertial idle distance by taking into account the road surface condition detected by the road condition detecting means.

Images