Hybrid Engine Temperature Control for Stable EV Mode Duration
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Solution Overview
Problem
Existing systems for controlling the starting and stopping of an internal combustion engine in hybrid vehicles lead to frequent and undesirable temperature fluctuations, which can result in inefficient operation and energy waste.
Innovation Solution
The engine is controlled based on temperature parameters, with threshold values set to maintain a warmed-up state by starting when temperatures drop to a first threshold and stopping when they rise to a second threshold, ensuring a target duration of electric vehicle (EV) mode operation by adjusting these thresholds according to temperature reduction characteristics and travel patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the internal combustion engine is started and stopped based on simple temperature threshold comparison, then the engine can be kept warmed up, but the starting and stopping will be repeated frequently
Solution Approach 1:
The patent applies dynamics by making the stop threshold dynamic rather than fixed. The stop threshold is adjusted based on the elapsed time since engine start and the temperature reduction characteristic. This allows the stop threshold to adapt over time, ensuring that the engine remains running long enough to complete a meaningful EV mode operation cycle while still maintaining warmth, thereby reducing frequent start-stop cycles and improving operational efficiency.
Solution Approach 2:
The patent changes the temperature parameter (stop threshold) based on time and temperature reduction characteristics. Instead of using a single fixed temperature value, the system calculates an appropriate stop threshold that accounts for how long the engine has been running and how quickly it cools down. This parameter adjustment prevents premature engine shutdown and subsequent frequent restarts, resolving the contradiction between maintaining temperature and avoiding frequent cycling.
2Temperature
If the internal combustion engine is operated continuously to maintain temperature, then the engine stays warmed up, but energy consumption increases
Solution Approach 1:
The patent implements periodic action by enabling the engine to stop during EV mode operation after a predetermined period, rather than running continuously. The system calculates an appropriate stop threshold based on time elapsed and temperature reduction characteristics, allowing the engine to shut down periodically when conditions permit. This periodic stopping reduces energy consumption while the engine remains capable of restarting when needed, balancing temperature maintenance with energy efficiency.
Data Source
AI summary
An internal combustion engine of a series hybrid vehicle starts generating power when a catalyst temperature or a coolant temperature has decreased to an activation temperature or a lower limit water temperature, and stops generating power when the catalyst temperature or the coolant temperature reaches an operation end temperature. A target duration time of EV mode operation is set, and respective temperature decrease rates are used to set the operation end temperature so that a difference in temperature relative to the activation temperature will be “ΔTC=Ra×Tev,” and to set the operation end temperature so that a difference in temperature relative to the lower limit water temperature will be “ΔTW=Rb×Tev.”