Engine Idle Stop Control Using Predicted Blowout Temperature
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Solution Overview
Problem
Existing control systems for internal combustion engines struggle to accurately determine engine restart timing during heating operations of air conditioners, leading to either prolonged engine stoppage times that lower vehicle compartment temperatures uncomfortably or shorter stoppage times that degrade fuel economy.
Innovation Solution
A control system that sets a lower limit blowout temperature and calculates an estimated blowout temperature using detected air conditioner suction temperature and power parameters, restarting the engine when the estimated temperature falls below this limit to maintain a comfortable compartment temperature while optimizing fuel economy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine stoppage time is extended to improve fuel economy, then fuel consumption is reduced, but the vehicle compartment temperature drops to uncomfortable levels
Solution Approach 1:
The control system performs preliminary calculation of the estimated blowout temperature before actually stopping the engine. By predicting the temperature trajectory using the temperature drop coefficient and current operating parameters, the system determines the optimal restart timing in advance, ensuring the compartment temperature remains comfortable while maximizing fuel economy benefits.
Solution Approach 2:
The system continuously monitors actual temperature parameters and compares them with predicted values. The temperature drop coefficient is updated based on actual observations, creating a feedback loop that improves prediction accuracy over time. This ensures the engine restart timing adapts to changing environmental conditions and maintains comfortable cabin temperature.
2Loss of energy
If the engine restart timing is delayed to maximize fuel economy, then fuel consumption decreases, but the blowout temperature becomes too low before restart
Solution Approach 1:
The control system calculates the estimated blowout temperature in advance before engine stoppage occurs. Using the temperature drop coefficient and current blowout temperature, the system predicts future temperature values at different time points, allowing determination of the optimal restart moment before the temperature becomes uncomfortably low.
Solution Approach 2:
The system dynamically adjusts the engine restart timing based on real-time temperature conditions and calculated temperature drop rates. Rather than using a fixed restart schedule, the control system continuously updates the predicted blowout temperature and adjusts restart timing to match actual thermal conditions, optimizing both comfort and fuel economy.
3Ease of operation
If the engine is restarted earlier to maintain comfortable temperature, then vehicle comfort is improved, but fuel economy performance deteriorates
Solution Approach 1:
The control system performs preliminary calculation of the estimated blowout temperature and determines the optimal engine restart timing before actual stoppage ends. By predicting when the temperature will reach the lower limit, the system schedules restart at the precise moment that maintains comfort while maximizing the beneficial stoppage duration for fuel economy.
Solution Approach 2:
The system replaces direct mechanical temperature monitoring with a computational prediction model. Instead of waiting for temperature sensors to detect actual temperature changes, the control system uses mathematical models based on temperature drop coefficients and operating parameters to predict future temperature states, enabling more precise and timely restart decisions.
Data Source
AI summary
A control system for an internal combustion engine, which is capable of properly determining timing for restarting the engine in a stopped state when idle stop control of the engine is executed during a heating operation of an air conditioner, thereby making it possible to ensure marketability and fuel economy performance in a well-balanced manner. The control system executes the idle stop control of the engine during the heating operation of the air conditioner. The control system includes an ECU. The ECU sets a lower limit blowout temperature, calculates an estimated blowout temperature, and controls the engine such that the engine is restarted when the estimated blowout temperature has become not higher than the lower limit blowout temperature.