Vehicle control in a reduced power mode
In at least some implementations, a method includes determining that a vehicle is operating in a reduced power mode, determining a destination of the vehicle, determining more than one route to the destination, determining one or more energy thresholds for each route, selecting one of the routes as a chosen route, and guiding the vehicle along the chosen route. The chose route may be selected based on the one or more energy thresholds and as a function of the energy output available from the vehicle.
1 . A method, comprising:
determining that a vehicle is operating in a reduced power mode in which the vehicle is operated after detection of a fault in operation of the vehicle, and in the reduced power mode one or both of the maximum speed of the vehicle is limited or the maximum torque that can be provided from a prime mover of a vehicle is limited;
determining a destination of the vehicle;
determining more than one route to the destination;
determining one or more energy thresholds for each route;
selecting one of the routes as a chosen route based on the one or more energy thresholds and as a function of the energy output available from the vehicle; and
guiding the vehicle along the chosen route with the vehicle being operated in the reduced power mode.
2 . The method of claim 1 wherein the one or more energy thresholds is a maximum power required for the vehicle to navigate any portion of each route, and wherein any route that has a maximum power that is greater than the lower power output provided by the prime mover in the reduced power mode is not selected.
3 . The method of claim 2 wherein the maximum power is determined as a function of at least: a) a road grade for a road within each route, and b) a speed limit of the road, and any route in which a predetermined speed cannot be maintained due to the road grade is not selected.
4 . The method of claim 3 wherein the maximum power is determined at a level equal to or within 15% or 10 mph of the speed limit.
5 . The method of claim 3 wherein the road has a minimum speed requirement and the maximum power is determined at a level equal to the minimum speed requirement.
6 . The method of claim 1 wherein the one or more energy thresholds is a total energy required for the vehicle to travel each route, and the total energy is compared to a vehicle range that is determined as a function of the energy available to propel the vehicle with the vehicle being operated in the reduced power mode.
7 . The method of claim 1 wherein guiding the vehicle is accomplished with a vehicle control system that controls steering, throttle and braking of the vehicle.
8 . The method of claim 1 wherein the reduced power mode results in the vehicle having less available torque from a prime mover of the vehicle, and the step of selecting one of the routes is accomplished as a function of the available torque.
9 . The method of claim 1 wherein the reduced power mode results in the vehicle having a reduced maximum speed, and the step of selecting one of the routes is accomplished as a function of the reduced maximum speed.
10 . The method of claim 9 wherein the reduced maximum speed is compared to a speed limit of each road along each route, and the step of selecting one of the routes is accomplished as a function of the maximum differential between reduced maximum speed and a highest speed limit in each route.
11 . The method of claim 1 wherein the chosen route is selected as a function of one or more of regulatory information, terrain information and current information.
12 . The method of claim 11 wherein the regulatory information includes one or more of a road speed limit, traffic rules, permitted direction(s) of travel, locations of intersections, and number of stops along a road.
13 . The method of claim 11 wherein the terrain information includes one or more of a road grade, and a type of road surface.
14 . The method of claim 11 wherein the current information includes one or more of a presence of construction, a lane closure, a traffic level, where the traffic level may be one or both of a current or predicted future traffic level.
15 . A method for controlling a vehicle operating in a reduced power mode, comprising:
determining multiple routes to a destination for the vehicle;
determining a minimum speed for each of multiple portions of each of the multiple routes, where the minimum speed is set as a function of a speed limit in each of the multiple portions;
comparing the minimum speeds required to reach the destination via each route against available power output from a prime mover of the vehicle while the vehicle is operated in the reduced power mode in which one or both of the maximum speed that the vehicle can achieve is limited compared to when the vehicle is not in the reduced power mode, or the maximum torque that can be provided from a prime mover of a vehicle is limited compared to when the vehicle is not in the reduced power mode; and either
a) selecting a chosen route from the multiple routes as a function of the ability of the vehicle to achieve the minimum speeds required to reach the destination; or
b) selecting a new destination when it is determined that the vehicle is not able to achieve the minimum speeds required to reach the destination along any of the multiple routes; and
guiding the vehicle in the reduced power mode along the chosen route with a vehicle control system controlling the steering and speed of the vehicle.
16 . The method of claim 15 wherein the ability of the vehicle to achieve the minimum speeds is determined as a function of a road grade for a road within each route.
17 . The method of claim 16 wherein the minimum speed is within 15% or 10 mph of the speed limit in each of the multiple portions.
18 . The method of claim 15 wherein the minimum speed required to reach the destination via each route is determined at a vehicle speed that is within 15% or 10 mph of the speed limits of roads in each route.