Method for decelerating a vehicle
View Patent ↗In a method for operating a vehicle, a current total mass of the vehicle is determined depending on a tractive force applied to accelerate the vehicle and, depending on the determined current total mass of the vehicle, the vehicle is decelerated. The build-up and/or reduction of a brake force for decelerating the vehicle depends on its total weight.
1. A method for operating vehicles, which comprises the steps of:
providing a vehicle selected from the group consisting of rail vehicles and passenger carrying rail vehicles, the vehicle having rail vehicle brakes;
determining a total weight of the vehicle depending on an acceleration of the vehicle, and a tractive force expended for the acceleration of the vehicle, the tractive force expended for the acceleration of the vehicle being determined in dependence on a motor current of a motor of the vehicle;
determining at least one of a build-up brake force or a reducing brake force for decelerating the vehicle depending on the total weight;
increasing or decreasing the brake force applied to the rail vehicle brakes linearly with time for decelerating the vehicle depending on the total weight, wherein a gradient is proportional to the total weight of the vehicle; and
continuously monitoring the brake force to maintain the brake force within a specified interval.
2. The method according to claim 1 , which further comprises determining the total weight of the vehicle in dependence on external forces acting on the vehicle.
3. The method according to claim 2 , which further comprises determining the total weight of the vehicle in dependence on at least one of gravitational forces acting on the vehicle or frictional forces acting on the vehicle.
4. The method according to claim 1 , wherein for determining a current total weight of the vehicle an empty weight m empty of the vehicle is known and a current load m load is calculated according to the following formula:
m
load
(
a
,
v
,
F
Z
,
α
)
=
-
a
*
m
empty
*
k
rot
+
F
Z
-
k
3
*
v
2
a
+
k
1
+
k
2
*
v
-
g
*
sin
α
-
m
empty
,
where:
a is an acceleration;
F z is a tractive force;
k rot is a known component of a rotating weight of the empty weight of the vehicle;
v is a current speed of the vehicle;
α is a slope angle of a track;
g is an acceleration due to gravity; and
k 1 through k 3 are known vehicle-specific running resistance constants.
5. The method according to claim 1 , wherein the build-up of the brake force and/or the reduction of the brake force for decelerating the vehicle takes place according to the following formula:
ⅆ
F
B
ⅆ
=
-
ⅆ
a
max
ⅆ
t
*
(
m
empty
*
(
1
+
k
rot
)
+
m
load
)
where:
m empty is a known empty weight of the vehicle;
k rot is a known component of a rotating weight in an empty weight of the vehicle;
m load is a current load; and
ⅆ
a
max
ⅆ
t
is a specified jolt limit value.
6. The method according to claim 1 , which further comprises performing the determining of the total weight of the vehicle during an acceleration process when the vehicle is at rest.
7. The method according to claim 1 , which further comprises outputting a signal on exceeding a specified threshold value for a specified total weight of the vehicle.
8. A rail vehicle for local passenger transport, comprising:
rail vehicle brakes; and
a computer programmed for calculating a total weight of a rail vehicle depending on an acceleration of the rail vehicle and on a tractive force expended for the acceleration of the rail vehicle, the tractive force expended for the acceleration of the vehicle being determined in dependence on a motor current of a motor of the vehicle, and said computer is further programmed for calculating at least one of a build-up of a brake force or a reduction of the brake force applied to said rail vehicle brakes for decelerating the vehicle depending on the total weight of the vehicle, wherein a gradient for increasing or decreasing the brake force linearly with time for decelerating the vehicle is proportional to the total weight of the vehicle.