Vehicle state estimation method and vehicular auxiliary brake control apparatus using the method

• US 6,249,735 B1
• Filed: 01/25/1999
• Issued: 06/19/2001
• Est. Priority Date: 01/28/1998
• Status: Expired due to Fees

• Current Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Inventors: Ishiguro, Toshiaki, Yamada, Naoki
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): PIPALA, EDWARD J
• Application Number:
  US09/236,438
• Time in Patent Office: 876 Days
• Field of Search: 701/1, 701/64, 701/65, 701/70, 701/93, 701/94
• US Class Current: 701/65
• CPC Class Codes: B60T 2250/02 Vehicle mass
• CPC Class Codes: B60T 8/18 responsive to vehicle weight or load, e.g. load distribution using electrical circuitry on regulation means B60T8/17; B60T8/30 takes precedence; responsive to weight and speed condition B60T8/58
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 10/18 including control of braking systems
• CPC Class Codes: B60W 10/196 acting within the driveline, e.g. retarders
• CPC Class Codes: B60W 2510/0604 Throttle position
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2530/10 Weight
• CPC Class Codes: B60W 2530/16 Driving resistance
• CPC Class Codes: B60W 2552/15 Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 30/18118 Hill holding
• CPC Class Codes: B60W 30/1819 Propulsion control with control means using analogue circuits, relays or mechanical links
• CPC Class Codes: G01G 19/08 for incorporation in vehicles

Abstract

A vehicle weight and a road surface gradient are estimated based on driving torque values and vehicle acceleration values when specific behavior occurs in a vehicle. Resulting estimation values are used for vehicle controls such as an engine control, an auxiliary brake control, and a transmission control.

Claims

1. A vehicle state estimation method comprising the step of estimating a vehicle weight based on driving torque and vehicle acceleration during a gear shift in a vehicle and

estimating a road surface gradient based on the vehicle weight.

2. The vehicle state estimation method according to claim 1, wherein the gear shift is a shift from a low gear to a second gear.

3. The vehicle state estimation method according to claim 1, further comprising the step of determining the driving torque by using a torque map.

4. A vehicular auxiliary brake control apparatus comprising:

road surface gradient detecting means for estimating a vehicle weight based on driving torque and vehicle acceleration when specific behavior occurs in a vehicle, and for detecting a road surface gradient based on the estimated vehicle weight;

brake state detecting means for detecting an operation state of the brake;

vehicle speed detecting means for detecting a speed of the vehicle; and

an auxiliary brake device for employing, as a target vehicle speed, a vehicle speed at a time point when the road surface gradient detecting means has detected a downhill slope and the brake state detecting means has detected a change from a brake operating state to a brake non-operating state during running on the downhill slope, and for decelerating the vehicle so that an actual vehicle speed becomes the target vehicle speed.

5. The vehicular auxiliary brake control apparatus according to claim 4, further comprising an accelerator state detecting means for detecting a state of an accelerator, wherein the auxiliary brake device is activated when the accelerator state detecting means has detected a non-operating state of the accelerator.

6. A vehicular auxiliary brake control method using:

road surface gradient detecting means for estimating a vehicle weight based on driving torque and vehicle acceleration when specific behavior occurs in a vehicle, and for detecting a road surface gradient based on the estimated vehicle weight;

brake state detecting means for detecting an operation state of a brake; and

vehicle speed detecting means for detecting a speed of the vehicle, the method comprising the steps of;

employing, as a target vehicle speed, a vehicle speed at a time point when the road surface gradient detecting means has detected a downhill slope and the brake state detecting means has detected a change from a brake operating state to a brake non-operating state during running on the downhill slope; and

performing an auxiliary brake control by operating an auxiliary brake device for decelerating the vehicle so that an actual vehicle speed becomes the target vehicle speed.

7. The vehicular auxiliary brake control method according to claim 6, wherein the auxiliary brake control is performed when the brake state detecting means has detected that a brake non-operating state has been established after a brake operating state continued for a predetermined time.