Hybrid Vehicle Torque Map Control for Cabin Heating
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Solution Overview
Problem
Hybrid electric vehicles face challenges in providing sufficient heat to warm the interior during cold and low-load conditions due to rapid battery discharge when the state of charge (SOC) is high, as the engine torque output is insufficient and electric heaters are inefficient.
Innovation Solution
A hybrid vehicle control method that utilizes different torque maps based on battery SOC, drive mode, and full automatic temperature controller (FATC) state to manage engine torque, enhancing heating performance by precisely controlling engine operation in cold and low-load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the engine is turned on to heat the vehicle interior when battery SOC is high and coolant temperature is low, then the vehicle interior can be heated, but the battery is rapidly discharged due to low engine torque output at low driving load
Solution Approach 1:
The system dynamically adjusts engine operation strategy based on real-time driving load conditions. When driving load is low and FATC is active, the engine operates in a warmed-up state to provide heating while managing battery discharge. When driving load increases, the system transitions to meeting driver torque requests, dynamically switching between heating mode and driving mode based on operational conditions
Solution Approach 2:
The system changes operational parameters by introducing a warm-up flag and adjusting engine torque maps based on driving load. The controller modifies engine control parameters (torque maps) according to the warm-up flag state, enabling the engine to operate at optimal temperatures for both heating and efficient battery usage under different load conditions
2Temperature
If the electric heater is used to heat the vehicle interior when battery SOC is high and driving load is low, then the vehicle interior can be heated, but the battery is rapidly discharged due to low heating efficiency
Solution Approach 1:
The system replaces the electric heating system with the engine's thermal output for vehicle interior heating. Instead of using the electric heater which consumes battery energy inefficiently, the engine's mechanical operation and associated thermal byproduct are utilized to provide heating through the FATC system, significantly reducing battery energy loss
3Force
If the engine torque is controlled to satisfy driver's requested torque in high SOC region, then the driver's torque demand is met, but sufficient heat source for vehicle interior heating cannot be secured
Solution Approach 1:
The control system segments the operating conditions into distinct modes using a warm-up flag: heating-priority mode (when warm-up flag is inactive, driving load is low, and FATC is active) and driving-priority mode (when warm-up flag is active or driving load is high). This segmentation allows the system to optimize for either heating or driving torque based on current conditions without compromise
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively secures a heat source for vehicle interior heating by optimizing engine torque through separate torque maps, improving heating performance even at low loads and high SOC, ensuring efficient battery usage and rapid temperature increase.
Implementation Method 1
an engine configured to generate power for driving the vehicle by combustion of fuel
Implementation Method 2
a drive motor configured to generate another power for driving the vehicle and selectively generate electrical energy by operating as a generator
Data Source
AI summary
A hybrid vehicle includes an engine configured to generate power for driving the vehicle by combustion of fuel. The hybrid vehicle also includes a drive motor configured to generate another power for driving the vehicle and selectively generate electrical energy by operating as a generator. The hybrid vehicle also includes a battery configured to supply electrical energy to the drive motor or to be charged by the electrical energy generated by the drive motor. The hybrid vehicle also includes the controller configured to control an operation of the engine by using different torque maps based on a driver's requested torque, a state of charge (SOC) of the battery, a drive mode of the vehicle, an operation state of a full automatic temperature controller (FATC), and a coolant temperature.