Pressure Accumulator for Engine Stop/Start Lubrication
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Solution Overview
Problem
The stop/start system in heavy vehicles leads to increased risk of metal-to-metal contact and abrasive wear in sliding bearings due to low viscosity lubricating oil when the engine is restarted, as the oil drains from bearings during shutdown, causing unstable conditions and rapid wear.
Innovation Solution
A pressure accumulator connected to the engine lubricant oil system via an actuated shut-off valve maintains and rapidly restores oil pressure to the bearings during engine shutdown and startup, ensuring lubrication before the oil pump can operate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine is stopped to reduce fuel consumption and emissions, then fuel efficiency is improved, but the lubricating oil drains from the bearings causing metal-to-metal contact and increased wear
Solution Approach 1:
The pressure accumulator stores pressurized lubricating oil in advance during engine operation. When the engine stops, the accumulator automatically supplies stored pressure to the bearings before the oil pump can replenish oil, preventing metal-to-metal contact during the critical startup period.
Solution Approach 2:
The pressure accumulator acts as an intermediary between the oil pump and the engine bearings. It maintains continuous oil pressure to the bearings during engine shutdown and startup transitions, bridging the gap when the main oil pump is not operational.
2Productivity
If the engine is restarted quickly after stopping, then productivity is improved, but the risk of metal-to-metal contact in bearings increases due to insufficient oil pressure
Solution Approach 1:
The pressure accumulator prepares and stores pressurized oil in advance during engine operation. Upon engine shutdown, it immediately supplies stored pressure to the bearings, enabling rapid engine restart without compromising bearing lubrication during the critical initial seconds.
Solution Approach 2:
The system uses hydraulic pressure storage in the pressure accumulator to maintain oil pressure to the bearings during engine shutdown. The stored hydraulic energy enables immediate oil supply upon restart, eliminating the delay between shutdown and lubrication restoration.
3Reliability
If a pressure accumulator is added to maintain oil pressure during shutdown, then bearing lubrication is improved, but device complexity increases
Solution Approach 1:
The pressure accumulator is integrated into the existing engine oil system, combining its pressure storage function with the main oil circulation system. This merging approach adds the necessary lubrication protection while minimizing the increase in overall system complexity.
Solution Approach 2:
The pressure accumulator automatically charges during engine operation when oil pressure is high and automatically discharges during engine shutdown when pressure is needed, without requiring external control systems. This self-regulating behavior simplifies the control architecture while maintaining reliable bearing lubrication.
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 effectively reduces bearing wear by maintaining and rapidly restoring oil pressure to the bearings, preventing metal-to-metal contact and extending engine longevity.
Implementation Method 1
a pressure accumulator (12) connected via at least one connection (14) to the engine oil system (16)
Implementation Method 2
the lubricating oil will quickly run out of the so-called sliding bearings... ensuring lubrication of the bearings
Data Source
Figure 1~4
AI summary
An arrangement (2) in connection with an engine (4) for a vehicle equipped with a stop/start system (6) that enables the engine (4) to start and stop in dependence upon a respective start or stop signal (8, 10) when predetermined conditions are fulfilled. The arrangement comprises at least one pressure accumulator (12) connected via at least one connection (14) to the engine oil system (16), and the connection (14) is equipped with a shut-off valve (18), wherein the shut-off valve (18) is adapted so as to be in an open position in which oil can flow in both directions between the engine oil system (16) and said pressure accumulator (12), or in a closed position in which oil is prevented from flowing through the valve (18). The position of the shut-off valve (18) is adapted so as to be controlled by a valve control signal (20), so that the valve (18) transitions to the open position in dependence upon the generation of a start signal (8) by said stop/start system (6), and transitions to the closed position in dependence upon the generation of a stop signal (10) by said stop/start system (6).