Vehicle control device and vehicle control method

Patent metadata

Field	Value
Publication number	US-10550785-B2
Application number	US-201515501763-A
Country	US
Kind code	B2
Filing date	Jul 1, 2015
Priority date	Sep 19, 2014
Publication date	Feb 4, 2020
Grant date	Feb 4, 2020

Abstract

Provided is a vehicle control device with which improved fuel economy and lowered exhaust gas emissions can be effectively achieved without adversely affecting the driver when traveling while following a leading vehicle. The present invention has: a following-determination means that, during travel while following a leading vehicle, determines, on the basis of the speed of the host vehicle, the speed of the leading vehicle, and the distance from the leading vehicle, whether the host vehicle will be able to follow the leading vehicle by coasting; and an idle stop determination means that, when the following-determination means has determined that the host vehicle will be able to follow the leading vehicle by coasting, and the driving/travel state of the host vehicle satisfies other traveling idle stop criteria, determines that a traveling idle stop should be performed; and is provided with a determination criteria updating means for updating the determination criteria for the idle stop determination means in regard to criteria such as the leading vehicle characteristics, road surface conditions, and weather. In the event that it has been determined, from the determination conditions that have been updated in regard to the leading vehicle characteristics, etc., that following by coasting is possible, a control to shut off the on-board engine is performed.

First claim

The invention claimed is:

1. A vehicle control system comprising:
a vehicle control device that performs a traveling idle stop that temporarily stop an in-vehicle engine when a driving/travel state of a host vehicle satisfies a first traveling idle stop condition while the host vehicle follows a leading vehicle, wherein the vehicle control device includes
a following determination unit that determines whether or not the host vehicle is able to follow the leading vehicle by inertia traveling, during which the in-vehicle engine is stopped, based on a speed of the host vehicle, a speed of the leading vehicle, and a distance between the host vehicle and the leading vehicle;
an idle stop determination unit that determines whether or not to perform the traveling idle stop if the driving/travel state of the host vehicle satisfies a second traveling idle stop condition and the following determination unit determines that the host vehicle is able to follow the leading vehicle by the inertia traveling;
a determination condition update unit that updates a determination condition of the idle stop determination unit based on a characteristic of the leading vehicle, road surface condition, and weather,
an excess kinetic energy calculating unit that calculates a difference between kinetic energy of the host vehicle and a predicted kinetic energy of the host vehicle, the excess kinetic energy calculating unit assuming that the host vehicle travels at the speed of the leading vehicle, and the excess kinetic energy calculating unit performing the calculation based on the weight of the host vehicle and the speed of the host vehicle; and
a loss kinetic energy calculating unit that calculates a loss of kinetic energy of the host vehicle based on the weight of the host vehicle, the speed of the host vehicle, a predicted deceleration speed or travel resistance of the host vehicle, the distance between the host vehicle and the leading vehicle, and relative height of the leading vehicle, wherein
the following determination unit determines whether or not there is sufficient kinetic energy for the host vehicle to follow the leading vehicle with inertia traveling on the basis of the calculated excess kinetic energy and the loss kinetic energy corrected by a gain updated by the determination condition update unit with the condition including the characteristic of the leading vehicle, the road surface condition, and the weather.

2. The vehicle control system according to claim 1 , wherein the determination condition update unit is a unit for determining whether kinetic energy for following exists for detecting frequency of acceleration/deceleration speed of the leading vehicle on the basis of history of the speed of the leading vehicle and updating the determination condition when the frequency of the acceleration/deceleration speed exceeds a predetermined threshold value.

3. The vehicle control system according to claim 1 , wherein the determination condition update unit detects a vehicle type of the leading vehicle and updates the determination condition if the vehicle type matches a registered one.

4. The vehicle control system according to claim 3 , wherein the idle stop determination unit restarts the in-vehicle engine if the following determination unit determines that the kinetic energy for following is insufficient while the in-vehicle engine is stopped.

5. The vehicle control system according to claim 1 , wherein the idle stop determination unit restarts the in-vehicle engine if pressing of an accelerator pedal is detected while the in-vehicle engine is stopped.

6. The vehicle control system according to claim 1 , wherein the idle stop determination unit restarts the in-vehicle engine if pressing of an accelerator pedal is detected while the in-vehicle engine is stopped.

7. The vehicle control system according to claim 6 , wherein the idle stop determination unit applies an operational reaction force to the accelerator pedal in addition to an ordinary restoring force if the following determination unit determines that there is sufficient kinetic energy for following, and cancels application of the operational reaction force if the following determination unit determines that the kinetic energy for following is insufficient and if the accelerator pedal is pressed more or pressed for a predetermined period or more even though the operational reaction force is kept applied.

8. The vehicle control system according to claim 1 , wherein the idle stop determination unit stops the in-vehicle engine regardless of whether or not detection of the kinetic energy for following by the following determination unit is sufficient while pressing of a brake pedal is being detected when traveling at low speed.

9. The vehicle control system according to claim 1 , wherein the idle stop determination unit stops the in-vehicle engine as long as another traveling idle stop condition is satisfied regardless of brake pedal operation if the following determination unit determines that there is sufficient kinetic energy for following when traveling at high speed.

10. A vehicle control method comprising:
performing a traveling idle stop, using a vehicle control device that temporarily stops an in-vehicle engine when a driving/travel state of a host vehicle satisfies a first traveling idle stop condition while the host vehicle follows a leading vehicle;
determining whether or not the host vehicle is able to follow the leading vehicle by inertia traveling, during which the in-vehicle engine is stopped, using a following determination unit which bases the determining step on a speed of the host vehicle, a speed of the leading vehicle, and a distance between the host vehicle and the leading vehicle;
determining whether or not to perform the traveling idle stop, using an idle stop determination unit, if the driving/travel state of the host vehicle satisfies a second traveling idle stop condition and the following determination unit determines that the host vehicle is able to follow the leading vehicle by the inertia traveling;
updating a determination condition of the idle stop determination unit, using a determination condition update unit, based on a characteristic of the leading vehicle, road surface condition, and weather;
calculating a difference between kinetic energy of the host vehicle and a predicted kinetic energy of the host vehicle, using an excess kinetic energy calculating unit, the excess kinetic energy calculating unit assuming that the host vehicle travels at the speed of the leading vehicle, and the excess kinetic energy calculating unit performing the calculation based on the weight of the host vehicle and the speed of the host vehicle; and
calculating a loss of kinetic energy of the host vehicle, using a loss kinetic energy calculating unit, based on the weight of the host vehicle, the speed of the host vehicle, a predicted deceleration speed or travel resistance of the host vehicle, the distance between the host vehicle and the leading vehicle, and relative height of the leading vehicle, wherein
the following determination unit determines whether or not there is sufficient kinetic energy for the host vehicle to follow the leading vehicle with inertia traveling on the basis of the calculated excess kinetic energy and the loss kinetic energy corrected by a gain updated by the determination condition update unit with the condition including the characteristic of the leading vehicle, the road surface condition, and the weather.

Assignees

• Hitachi Automotive Systems Ltd

Inventors

• Kawakami Tomonori
• Imanishi Yuto
• Shibata Takeo

Classifications

• B60W30/18072

  Coasting · CPC title

• F02P5/1522

  with particular means concerning an individual cylinder · CPC title

• B60W2552/40

  Coefficient of friction · CPC title

• B60W2552/15

  Road slope, i.e. the inclination of a road segment in the longitudinal direction · CPC title

• F02N5/04

  of inertia type · CPC title