Method for increasing active duration time of an automatic freewheeling function in a vehicle

• US 8,332,120 B2
• Filed: 04/20/2007
• Issued: 12/11/2012
• Est. Priority Date: 04/20/2007
• Status: Active Grant

• Current Assignee: Volvo Lastvagnar AB (Volvo AB)
• Original Assignee: Volvo Lastvagnar AB (Volvo AB)
• Inventors: Eriksson, Anders, Bjernetun, Johan
• Primary Examiner(s): FREJD, RUSSELL WARREN
• Application Number:
  US12/596,674
• Publication Number:
  US 20100152990A1
• Time in Patent Office: 2,062 Days
• Field of Search: 701 93- 98, 477/97
• US Class Current: 701/93
• CPC Class Codes: B60K 31/00 Vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed, i.e. preventing speed from exceeding an arbitrarily established velocity or maintaining speed at a particular velocity, as selected by the vehicle operator fittings acting on two or more sub-units B60W30/14; speedometers G01P; systems or devices for controlling speed in general G05D13/00 ; in traffic anti-collision system for road vehicles G08G1/16
• CPC Class Codes: B60K 31/0058 responsive to externally generated signalling
• 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 30/143 Speed control B60W30/16 takes precedence
• CPC Class Codes: B60W 30/18072 Coasting
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A method for increasing active duration time of an automatic freewheeling function in a vehicle with cruise control and during a cruise control active period is provided. The function includes an arrangement for determining a vehicle set speed (Vset speed) for when the function is allowed to be activated and an arrangement for calculating a predetermined allowable vehicle speed drop to a first under speed value (Vunderspeed) below the vehicle set speed (Vset speed), The function is controlled based on the under speed value, in order to extend active duration time of the function.

Claims

1. Method for increasing active duration time of an automatic freewheeling function in a vehicle with cruise control and during a cruise control active period, the function comprising means for determining a first vehicle set speed (Vset speed) for when the function is allowed to be activated under at least prevailing conditions, comprising:

calculating a predetermined allowable vehicle speed drop (d) to a first under speed value (Vunderspeed) below the first vehicle set speed (Vset speed) for at least prevailing conditions and;

controlling the function based on the under speed value, in order to extend active duration time of the function.

2. Method as claimed in claim 1, wherein the controller comprises the step of inactivating the function when vehicle speed has decreased down to the first under speed value from a vehicle speed above the under speed value and when the function is active.

3. Method as claimed in claim 1, wherein the magnitude of the vehicle under speed value will not be lower than that of a highest gear of a transmission in the vehicle, or a gear engaged just before the freewheel function was activated, will be possible to reengage when the vehicle speed reaches the vehicle under speed value and the freewheel function will be inactivated and a gear will have to be engaged.

4. Method as claimed in claim 1, wherein the predetermined vehicle speed drop will not occur if the vehicle is expected to meet increased travel resistance in the near future.

5. Method as claimed in claim 1, wherein the controller comprises the step of activating the function when vehicle speed has increased up to at least the first under speed value from a vehicle speed below the under speed value and when the function is inactive.

6. Method as claimed in claim 5, wherein the force of gravity is the main contributor to the vehicle speed increase.

7. Method as claimed in claim 1, wherein the calculation of the magnitude of the allowed predetermined vehicle speed drop is dependent on the vehicle'"'"'s ability to accelerate up to the first vehicle set speed from the first under speed value within a reasonable predetermined time (ti).

8. Method as claimed in claim 1, wherein the vehicle under speed value can be manually set for at least one first vehicle set speed by the driver.

9. Method as claimed in claim 1, wherein the vehicle under speed value can be factory-set for one or several different first vehicle set speeds or set by authorized workshop personnel.

10. Method as claimed in claim 1, wherein the first under speed value is defined as a second vehicle set speed.

11. A non-transitory computer readable storage medium storing a computer program comprising a program code for executing the method as claimed in claim 1.