COASTING CONTROL DEVICE AND METHOD FOR VEHICLE

• US 20150166065A1
• Filed: 10/21/2013
• Published: 06/18/2015
• Est. Priority Date: 10/24/2012
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Kuroki, Rentaro, Hirai, Takuya, Mitsuyasu, Masaki, Kim, Jonggap, Matsunaga, Masaki, Kido, Yasunari, Suzuki, Takeaki, Kogure, Takayuki, Okamura, Yukari, Sato, Akihiro, Kinoshita, Yusuke
• Granted Patent: US 9,598,082 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60T 13/662 characterised by specified functions of the control system components
• CPC Class Codes: B60T 2201/04 Hill descent control
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 10/188 hydraulic brakes
• CPC Class Codes: B60W 10/30 including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
• CPC Class Codes: B60W 2030/18081 With torque flow from driveshaft to engine, i.e. engine being driven by vehicle
• CPC Class Codes: B60W 2030/1809 Without torque flow between driveshaft and engine, e.g. with clutch disengaged or transmission in neutral
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: B60W 2552/15 Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 2710/182 Brake pressure, e.g. of fluid or between pad and disc
• CPC Class Codes: B60W 30/18072 Coasting
• CPC Class Codes: B60W 30/18136 Engine braking
• CPC Class Codes: F02D 2200/602 Pedal position
• CPC Class Codes: F02D 2250/41 Control to generate negative pressure in the intake manifold, e.g. for fuel vapor purging or brake booster
• CPC Class Codes: F02D 41/12 for deceleration F02D41/0005, F02D41/107 take precedence
• CPC Class Codes: Y02T 10/60 : Other road transportation technologies with climate change mitigation effect

Abstract

In consideration of an amplification effect of a braking force at the time of brake operation, there is provided a difference between upper-limits (α, β) of a brake operation force (Brk) with which the execution of free-run coasting and neutral coasting is started, on the basis of whether or not a brake booster (42) can be filled with a negative pressure. Therefore, while the braking force at the time of brake operation is secured, the range of the brake operation force (Brk) with which coasting is executed can be enlarged, and an improvement in fuel economy can be made.

Claims

1. A control device for a vehicle including an engine, a brake operation member that is operated on a basis of a driver'"'"'s brake requirement amount, and a brake booster that amplifies a brake force with use of a negative pressure generated through rotation of the engine, the control device comprising:

a controller configured to execute engine connection travelling that allows to execute engine brake travelling during which the engine is connected to a wheel and is drivingly rotated through rotation of the wheel such that the vehicle travels with engine brake effectuated, the controller being configured to execute first coasting when the brake requirement amount is equal to or smaller than a predetermined first criterial value, the controller being configured to execute second coasting when the brake requirement amount is equal to or smaller than a predetermined second criterial value that is larger than the first criterial value, the controller being configured to set an engine brake force during the first coasting or the second coasting smaller than an engine brake force during the engine brake travelling, the controller being configured to stop the engine and cause the vehicle to travel during the first coasting, and the controller being configured to rotate the engine and cause the vehicle to travel during the second coasting.

2. The control device according to claim 1, wherein

the controller is configured to stop supplying fuel to the engine and drivingly rotate the engine in accordance with a vehicle speed during the engine brake travelling at a time of the engine connection travelling, and

the controller is configured to execute the engine brake travelling when the brake requirement amount exceeds the second criterial value.

3. The control device according to claim 1, wherein

the controller is configured to set the first criterial value and the second criterial value in accordance with a gradient of a road surface, and

the controller is configured to set the first criterial value and the second criterial value in a case where the road surface is a downhill gradient smaller than the first criterial value and the second criterial value in a case where the road surface is a flat road, respectively.

4. The control device according to claim 1, wherein

the controller is configured to set the first criterial value and the second criterial value in accordance with a gradient of a road surface, and

the controller is configured to set the first criterial value and the second criterial value in a case where the road surface is an uphill gradient larger than the first criterial value and the second criterial value in a case where the road surface is a flat road, respectively.

5. The control device according to claim 1, wherein

the controller is configured to make a transition to the second coasting when the brake requirement amount has exceeded the first criterial value during execution of the first coasting, and

the controller is configured to make a transition to the engine connection travelling when the brake requirement amount has exceeded the second criterial value during execution of the second coasting.

6. The control device according to claim 1, wherein

the first coasting is coasting during which the engine is disconnected from the wheel and fuel is stopped from being supplied to the engine such that the engine is stopped, and

the second coasting is coasting during which the engine is disconnected from the wheel and fuel is supplied to the engine such that the engine is operated.

7. The control device according to claim 1, wherein

the first coasting is coasting during which the engine is disconnected from the wheel and fuel is stopped from being supplied to the engine such that the engine is stopped, and

the second coasting is coasting during which the engine and the wheel are connected to each other, fuel is stopped from being supplied to the engine, and at least one of operation of a piston or pistons and operation of intake and exhaust valves in at least one of a plurality of cylinders of the engine is stopped.

8. A control method for a vehicle including an engine, a brake operation member that is operated on a basis of a driver'"'"'s brake requirement amount, a brake booster that amplifies a brake force with use of a negative pressure generated through rotation of the engine, and a controller, the control method comprising:

executing, by the controller, engine connection travelling that allows to execute engine brake travelling during which the engine is connected to a wheel and is drivingly rotated through rotation of the wheel such that the vehicle travels with engine brake effectuated;

executing, by the controller, first coasting when the brake requirement amount is equal to or smaller than a predetermined first criterial value;

executing, by the controller, second coasting when the brake requirement amount is equal to or smaller than a predetermined second criterial value that is larger than the first criterial value;

setting, by the controller, an engine brake force during the first coasting or the second coasting smaller than an engine brake force during the engine brake travelling;

stopping the engine and causing the vehicle, by the controller, to travel during the first coasting; and

rotating the engine and causing the vehicle, by the controller, to travel during the second coasting.