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A method for controlling a downhill speed control system in a vehicle

IP.com Disclosure Number: IPCOM000240175D
Publication Date: 2015-Jan-09
Document File: 3 page(s) / 67K

Publishing Venue

The IP.com Prior Art Database

Abstract

In some downhill speed control system it is possible for a driver to manually adjust the pre-set target speed while driving the vehicle. The pre-set target speed can be adjusted in steps of a predetermined size upwards and downwards by means of a button or the like. The new target speed is determined as the pre-set target speed ± number of steps indicated by the driver during all operating conditions except than the driver indicates the new target speed when the current speed of the vehicle is lower than the pre-set target speed and the driver has activated a brake in the vehicle. In this case, the new target speed is determined as the current speed of the vehicle ± number of steps indicated by the driver.

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A method for controlling a downhill speed control system in a vehicle

Heavy vehicles are many times equipped with a downhill speed control system. The downhill speed system activates and controls one or several auxiliary brakes in the vehicle, for example a retarder, so that the auxiliary brake is automatically activated 5 when the vehicle exceeds a pre-set target speed which may occur when the vehicle travels down a hill. The downhill speed system can be used together with a cruise control system. In this case, the pre-set target speed can be related to the selected cruising speed of the cruise control system.

10 In some downhill speed control system it is possible for a driver to manually adjust the pre-set target speed while driving the vehicle. The pre-set target speed can be adjusted in steps of a predetermined size upwards and downwards by means of a button or the like. The number of presses of the button corresponds to the number of adjusting steps upwards or downwards of the pre-set target speed. Such a button may have an area

15 marked with a plus sign and another area marked with a minus sign to be pressed by the driver when the pre-set target speed is to be adjusted upwards or downwards.

In an existing method for manually adjusting the pre-set target speed, the system selects the lowest speed of the existing target speed and the current speed of the 20 vehicle as the speed to be adjusted to a new target speed. This can be perceived as illogical in certain operating situation and be a problem for a driver. If, for example, the current speed of the vehicle is lower than the existing target speed and the driver wishes to increase the existing target speed. In this case, the driver has to calculate the number of presses on button from the current speed up to the desired new pre-set target

30 to the flow chart below. The method and the vehicle start at step 1. The downhill speed control system comprises an electric control unit. At step 2, the control unit receives information about a pre-set target speed at which an auxiliary brake is automatically activated. The control unit receives information about the current speed at step 3. At step 4, it is indicated that the driver desires a new target speed. The driver indicates the desired new target speed with a number of presses on, for example, a button of the downhill speed control system. The driver may indicate the new target speed by a number of presses on an area of the button marked with a plus sign or an area marked with a minus sign. Each press of the button indicates a predetermined stepwise incr...