Brake assisted vehicle engine restart on a road grade

• US 9,457,811 B2
• Filed: 09/17/2009
• Issued: 10/04/2016
• Est. Priority Date: 09/17/2009
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Yu, Hai, McGee, Ryan A., Soliman, Ihab S., Boesch, Mathew A.
• Primary Examiner(s): HILGENDORF, DALE W
• Application Number:
  US12/561,502
• Publication Number:
  US 20110065548A1
• Time in Patent Office: 2,574 Days
• Field of Search: 701/22, 701/48, 701/51, 701/70, 701/82, 701/83, 701/87, 701/112, 701/113, 477/195, 477/102, 477/203, 477/111, 477/205, 303/192, 290/40.A, 290/40.B, 290/40.C, 290/40.D, 290/40.R
• US Class Current: 1/1
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 10/115 with planetary gears
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 2510/0657 Engine torque
• CPC Class Codes: B60W 2510/105 Output torque
• CPC Class Codes: B60W 2520/30 Wheel torque
• CPC Class Codes: B60W 2552/15 Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 2710/1005 Transmission ratio engaged
• CPC Class Codes: B60W 2710/182 Brake pressure, e.g. of fluid or between pad and disc
• CPC Class Codes: B60W 30/18027 Drive off, accelerating from standstill
• CPC Class Codes: B60W 30/18054 at stand still, e.g. engine in idling state hill holding B60W30/18118
• CPC Class Codes: B60W 30/18118 Hill holding

Abstract

A method for restarting an engine of a vehicle stopped on a grade, comprising the steps of engaging a gear of a transmission through which the engine and wheels of the vehicle are driveably connected mutually, using brake pressure to engage wheel brakes and produce a road gradient wheel torque that holds the vehicle stationary on the grade, initiating an engine restart, operating the engine to produce wheel torque equal to or greater than the road gradient wheel torque, and releasing the brake pressure.

Claims

1. A system for restarting an engine of a vehicle stopped on a grade, comprising:

wheels for propelling the vehicle;

wheel brakes for alternately holding and releasing rotation of the wheels;

a brake system for pressurizing the wheel brakes;

the engine;

a starter motor connectable to the engine;

a transmission engaged in a gear through which the engine is driveably connected to the wheels; and

a controller configured to automatically stop the engine, automatically apply brake pressure to produce wheel brake torque capacity sufficient to hold the vehicle stationary on the grade and oppose combustion torque when the engine restarts, use the starter motor to crank the engine initiating an engine restart, start a timer, automatically release brake torque if the timer expires before engine speed peaks, maintain said brake torque and reset the timer if the engine speed peaks before the timer expires, and automatically release brake torque if the reset timer expires or the engine produces a road gradient wheel torque; and

wherein the controller is further configured to adaptively determine the brake torque with reference to road gradient information and initial combustion torque surge magnitude, and to hold the vehicle in standstill on the grade.

2. A system for restarting an engine of a vehicle stopped on a grade, comprising:

wheels for propelling the vehicle;

wheel brakes for alternately holding and releasing rotation of the wheels;

a brake system for pressurizing the wheel brakes;

the engine;

a starter motor connectable to the engine;

a transmission engaged in a gear through which the engine is driveably connected to the wheels; and

a controller configured to automatically stop the engine, automatically apply brake pressure to produce wheel brake torque capacity sufficient to hold the vehicle stationary on the grade and oppose combustion torque when the engine restarts, use the starter motor to crank the engine initiating an engine restart, start a timer, automatically release brake torque if the timer expires before engine speed peaks, maintain said brake torque and reset the timer if the engine speed peaks before the timer expires, and automatically release brake torque if the reset timer expires or the engine produces a road gradient wheel torque; and

wherein the controller is further configured to determine the brake torque for an uphill vehicle launch from the relationship T_HSBA=max(T_RL, T_TSM)+T_sm, wherein T_TSM is the torque for initial combustion torque mitigation, T_RS is a gradient wheel torque, and T_SM is a torque safety margin.

3. A system for restarting an engine of a vehicle stopped on a grade, comprising:

wheels for propelling the vehicle;

wheel brakes for alternately holding and releasing rotation of the wheels;

a brake system for pressurizing the wheel brakes;

the engine;

a starter motor connectable to the engine;

a transmission engaged in a gear through which the engine is driveably connected to the wheels; and

a controller configured to automatically stop the engine, automatically apply brake pressure to produce wheel brake torque capacity sufficient to hold the vehicle stationary on the grade and oppose combustion torque when the engine restarts, use the starter motor to crank the engine initiating an engine restart, start a timer, automatically release brake torque if the timer expires before engine speed peaks, maintain said brake torque and reset the timer if the engine speed peaks before the timer expires, and automatically release brake torque if the reset timer expires or the engine produces a road gradient wheel torque; and

wherein the controller is further configured to determine the brake torque for a downhill vehicle launch from the relationship T_HSBA=|T_RL|+T_TSM+T_SM, wherein T_TSM is the torque for initial combustion torque mitigation, T_RL is a gradient wheel torque, and T_SM is a torque safety margin.