Coasting control device and method for vehicle

• US 9,598,082 B2
• Filed: 10/21/2013
• Issued: 03/21/2017
• 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
• Primary Examiner(s): Burgess, Ramya
• Assistant Examiner(s): MORRIS, DAVID R.
• Application Number:
  US14/413,340
• Publication Number:
  US 20150166065A1
• Time in Patent Office: 1,247 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, upper-limits (α, β) of a brake operation force (Brk) with which the execution of free-run coasting and neutral coasting is started may be different, on the basis of whether or not a brake booster 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 control the vehicle to;

execute engine brake travelling so as to travel with engine brake effectuated by connecting the engine to a wheel so that the engine is drivingly rotated through rotation of the wheel,

execute first coasting when the brake requirement amount is equal to or smaller than a predetermined first criterial value,

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,

set an engine brake force during the first coasting and the second coasting smaller than an engine brake force during the engine brake travelling,

stop the engine and cause the vehicle to travel during the first coasting, and

rotate the engine and cause the vehicle to travel during the second coasting,

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.

2. 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 control the vehicle to;

execute engine brake travelling so as to travel with engine brake effectuated by connecting the engine to a wheel so that the engine is drivingly rotated through rotation of the wheel,

execute first coasting when the brake requirement amount is equal to or smaller than a predetermined first criterial value,

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,

set an engine brake force during the first coasting and the second coasting smaller than an engine brake force during the engine brake travelling,

stop the engine and cause the vehicle to travel during the first coasting, and

rotate the engine and cause the vehicle to travel during the second coasting,

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.

3. 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 control the vehicle to;

execute engine brake travelling so as to travel with engine brake effectuated by connecting the engine to a wheel so that the engine is drivingly rotated through rotation of the wheel,

execute first coasting when the brake requirement amount is equal to or smaller than a predetermined first criterial value,

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,

set an engine brake force during the first coasting and the second coasting smaller than an engine brake force during the engine brake travelling,

stop the engine and cause the vehicle to travel during the first coasting, and

rotate the engine and cause the vehicle to travel during the second coasting,

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 brake travelling when the brake requirement amount has exceeded the second criterial value during execution of the second coasting.

4. 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 control the vehicle to;

execute engine brake travelling so as to travel with engine brake effectuated by connecting the engine to a wheel so that the engine is drivingly rotated through rotation of the wheel,

execute first coasting when the brake requirement amount is equal to or smaller than a predetermined first criterial value,

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,

set an engine brake force during the first coasting and the second coasting smaller than an engine brake force during the engine brake travelling,

stop the engine and cause the vehicle to travel during the first coasting, and

rotate the engine and cause the vehicle to travel during the second coasting, 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.