Hydraulic Accumulator Pump Priming for Vehicle Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Vehicle transmission systems face line pressure instability and pump fluid starvation due to low hydraulic fluid pressure, especially when the engine has been shut down for an extended period, leading to inefficiencies and increased emissions when trying to prime the pump.
Innovation Solution
A controller is programmed to discharge an accumulator to prime the pump when the engine starts and the fluid temperature is below a threshold, ensuring adequate hydraulic fluid pressure without increasing engine speed or idling, thus maintaining fuel economy and immediate vehicle readiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the engine is started after extended shutdown, then the vehicle needs to operate immediately, but the hydraulic fluid pressure is too low to prime the pump effectively
Solution Approach 1:
The accumulator is pre-charged during engine operation to store hydraulic fluid under pressure. When the engine shuts down and needs to restart immediately, the accumulator discharges its stored pressure to prime the pump, eliminating the need for engine idling or extended warm-up periods.
Solution Approach 2:
The accumulator acts as an intermediary energy storage device between the pump and the hydraulic system. It decouples the pump operation from immediate hydraulic demand, allowing the pump to be primed quickly using stored energy from the accumulator rather than requiring continuous engine operation.
2Stress or pressure
If the engine speed is increased to prime the pump, then adequate hydraulic fluid pressure is achieved, but fuel economy decreases and emissions increase
Solution Approach 1:
The hydraulic system uses its own stored energy in the accumulator to prime the pump, rather than requiring external energy input through increased engine speed. The system serves itself by utilizing the pre-stored hydraulic pressure to overcome the priming requirement.
Solution Approach 2:
The system changes the pressure parameter by discharging the accumulator, which releases stored high-pressure hydraulic fluid to prime the pump. This pressure surge allows pump priming without requiring sustained high engine speed, thus avoiding increased fuel consumption and emissions.
3Stress or pressure
If the pump is primed using conventional methods, then hydraulic fluid pressure is stabilized, but the process takes time and delays vehicle operation
Solution Approach 1:
The accumulator is charged with hydraulic fluid under pressure during normal engine operation before shutdown. This preliminary action ensures that when the engine restarts, the pressure is already available immediately to prime the pump, eliminating delays.
Solution Approach 2:
The accumulator charges and discharges in periodic cycles corresponding to engine operation and shutdown. During engine run periods, the accumulator charges; during shutdown periods, it discharges to prime the pump, creating a rhythmic pattern that maintains system readiness without continuous operation.
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
This solution stabilizes line pressure and prevents pump starvation, enhancing transmission performance without increasing emissions or delaying vehicle use, while maintaining fuel efficiency.
Implementation Method 1
an accumulator disposed along the circuit. The controller is programmed to discharge the accumulator to prime the pump
Data Source
AI summary
A vehicle includes an engine, a transmission, and a controller. The transmission has clutches, a circuit configured to transport fluid to the clutches, a pump configured to circulate the fluid through the circuit, and an accumulator disposed along the circuit. The controller is programmed to, responsive to an engine start and a fluid temperature being less than a temperature threshold, discharge the accumulator to prime the pump.