Limiting speed based on state of charge

Electronic circuitry to control a utility vehicle, the electronic circuitry comprising:

• a battery system interface;
• and
• a controller coupled with the battery system interface, the controller being constructed and arranged to perform a method of:
• initially setting a maximum speed constraint imposed on the utility vehicle to an initial value,
• receiving, through the battery system interface, a state of charge signal that indicates a current state of charge of a lithium battery which provides electric power for utility vehicle propulsion, and
• based on the state of charge signal that indicates the current state of charge of the lithium battery, adjusting the maximum speed constraint imposed on the utility vehicle from the initial value to an adjusted value that is different from the initial value;
• wherein adjusting the maximum speed constraint imposed on the utility vehicle further includes:
• performing an incline assessment operation that indicates whether the utility vehicle is currently traveling down an incline to prevent the maximum speed constraint imposed on the utility vehicle from being lowered from a first speed limit to a second speed limit unless the utility vehicle is currently traveling down an incline;
• wherein the utility vehicle includes an electric motor constructed and arranged to provide utility vehicle propulsion;
• wherein performing the incline assessment operation includes:
• providing an incline assessment operation result indicating that the utility vehicle is traveling front-to-back down the incline in response to the electric motor rotating in a predefined direction and regenerating an amount of energy that exceeds an energy regeneration threshold;
• wherein the initial value is the first speed limit;
• wherein the adjusted value is the second speed limit that is slower than the first speed limit;
• wherein adjusting the maximum speed constraint imposed on the utility vehicle includes:
• lowering the maximum speed constraint imposed on the utility vehicle from the first speed limit to the second speed limit;
• and
• wherein adjusting the maximum speed constraint imposed on the utility vehicle further includes:
• performing a comparison operation that compares the current state of charge of the lithium battery indicated by the state of charge signal to a predefined state of charge threshold for the lithium battery, a result of the comparison operation indicating that the current state of charge of the lithium battery exceeds the predefined state of charge threshold for the lithium battery, the maximum speed constraint for the utility vehicle being lowered from the first speed limit to the second speed limit in response to the result of the comparison operation indicating that the current state of charge of the lithium battery exceeds the predefined state of charge threshold for the lithium battery.

A utility vehicle, comprising:

• a battery management system (BMS) having a lithium battery;
• a utility vehicle propulsion system constructed and arranged to provide utility vehicle propulsion using electric power from the lithium battery;
• and
• electronic circuitry coupled with the BMS and the utility vehicle propulsion system, the electronic circuitry being constructed and arranged to perform a method of:
• initially setting a maximum speed constraint imposed on the utility vehicle to an initial value,
• receiving, from the BMS, a state of charge signal that indicates a current state of charge of the lithium battery which provides electric power for utility vehicle propulsion, and
• based on the state of charge signal that indicates the current state of charge of the lithium battery, adjusting the maximum speed constraint imposed on the utility vehicle from the initial value to an adjusted value that is different from the initial value;
• wherein adjusting the maximum speed constraint imposed on the utility vehicle further includes:
• performing an incline assessment operation that indicates whether the utility vehicle is currently traveling down an incline to prevent the maximum speed constraint imposed on the utility vehicle from being lowered from a first speed limit to a second speed limit unless the utility vehicle is currently traveling down an incline;
• wherein the utility vehicle propulsion system includes an electric motor constructed and arranged to provide the utility vehicle propulsion;
• and
• wherein performing the incline assessment operation includes:
• providing an incline assessment operation result indicating that the utility vehicle is traveling front-to-back down the incline in response to the electric motor rotating in a predefined direction and regenerating an amount of energy that exceeds an energy regeneration threshold;
• wherein the initial value is the first speed limit;
• wherein the adjusted value is the second speed limit that is slower than the first speed limit;
• wherein adjusting the maximum speed constraint imposed on the utility vehicle includes:
• lowering the maximum speed constraint imposed on the utility vehicle from the first speed limit to the second speed limit;
• and
• wherein adjusting the maximum speed constraint imposed on the utility vehicle further includes:
• performing a comparison operation that compares the current state of charge of the lithium battery indicated by the state of charge signal to a predefined state of charge threshold for the lithium battery, a result of the comparison operation indicating that the current state of charge of the lithium battery exceeds the predefined state of charge threshold for the lithium battery, the maximum speed constraint for the utility vehicle being lowered from the first speed limit to the second speed limit in response to the result of the comparison operation indicating that the current state of charge of the lithium battery exceeds the predefined state of charge threshold for the lithium battery.