Idle Stop Go System Hydraulic Pressure Maintenance
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Solution Overview
Problem
Existing ISG systems do not effectively prevent fuel consumption due to unnecessary idling and do not maintain optimal operability after engine restart in vehicles with automatic transmissions.
Innovation Solution
An ISG system and method that control engine start and restart based on specific conditions, including maintaining hydraulic pressure with a sub-pump and enabling power steering, using an engine controller, motor-driven steering controller, automatic transmission controller, brake controller, and battery management system to manage engine stop and restart signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine is stopped to prevent unnecessary idling and reduce fuel consumption, then fuel efficiency is improved, but the operability and responsiveness of the vehicle after restart deteriorates
Solution Approach 1:
The patent applies preliminary action by maintaining hydraulic pressure in the automatic transmission using a sub-pump before the engine is restarted. The sub-pump keeps the transmission fluid under pressure during engine stop periods, so when the engine restarts, the transmission is already prepared and can immediately engage gears without delay. This eliminates the need for the transmission to rebuild pressure after restart, thereby maintaining smooth and responsive operability while still benefiting from engine stop fuel savings.
2Loss of energy
If the engine is stopped by ISG system, then fuel consumption is reduced, but the hydraulic pressure of automatic transmission decreases affecting transmission operability
Solution Approach 1:
The patent segments the hydraulic pressure maintenance function from the main engine-driven pump by introducing a separate sub-pump dedicated to the automatic transmission. This sub-pump is controlled independently by the engine controller and can operate autonomously during engine stop periods to maintain transmission hydraulic pressure. By separating these functions, the system can reduce engine fuel consumption while ensuring the transmission maintains sufficient pressure for immediate operation after restart.
3Loss of energy
If the engine is stopped by ISG system, then fuel consumption is reduced, but the power steering functionality may be affected
Solution Approach 1:
The patent introduces an intermediary control mechanism where the engine controller coordinates with the power steering controller to maintain steering functionality during engine stop. The engine controller receives signals from the power steering controller and adjusts the sub-pump operation or engine restart timing to ensure power steering remains operational. This intermediary coordination allows the system to reduce fuel consumption through engine stopping while guaranteeing that power steering functionality is preserved through controlled maintenance of hydraulic pressure or immediate restart capability.
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
Prevents fuel consumption by optimizing engine operation and maintaining seamless operability after restart by ensuring consistent hydraulic pressure and power steering functionality.
Implementation Method 1
keeping the hydraulic pressure of the automatic transmission with a sub-pump when the engine is stopped
Implementation Method 2
implement power steering by keeping a motor-driven steering controller operable, when the engine is stopped
Data Source
AI summary
An ISG system prevents fuel consumption due to unnecessary idling, by controlling the start of an engine, in accordance with engine stop conditions and restart conditions of a vehicle equipped with an automatic transmission. A method includes determining whether prior conditions for engine stop in an engine controller when an engine is in operation is satisfied, determining whether the engine can be stopped, when the prior conditions for engine stop are satisfied, determining whether engine stop conditions is satisfied, when the engine can be stopped, stopping the engine that is in operation, when the engine stop conditions are satisfied, determining whether key start conditions are satisfied, when the engine is stopped, determining whether restart is possible, when the key start conditions are not satisfied, determining whether conditions for restart are satisfied, when restart is possible, and restarting the engine, when the restart conditions are satisfied.