Supercharged Compressor Valve Unit for Peak Pressure Reduction
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Solution Overview
Problem
Commercial vehicle compressors face challenges in efficiently delivering compressed air at low engine speeds due to high peak pressures and increased air requirements, often resulting in the need for large valves and reduced air delivery when using conventional designs.
Innovation Solution
A charged compressor with a valve unit that engages a dead space to reduce air volume and peak pressures, allowing for adjustable valve cross sections and multiple valve operations to manage flow resistance and energy usage, and a clutch to disengage the compressor from the engine during low demand periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional valves are used to handle high volumetric flows at high charging pressures, then air throughput is improved, but peak pressures reach 20 to 30 bar which are significantly above the 12 to 18 bar without turbocharging
Solution Approach 1:
The compressor is divided into two independent compression stages: a first compression stage that compresses air to an intermediate pressure, and a second compression stage that compresses the air further to the final charging pressure. This segmentation allows each stage to operate at lower pressures, avoiding the excessive peak pressures (20-30 bar) that occur in single-stage compressors handling high volumetric flows.
Solution Approach 2:
The valve unit is made adjustable, allowing the valve cross section to be dynamically changed based on operating conditions. The valve can be adjusted to optimize flow resistance at different charging pressures, enabling the system to maintain efficient air throughput while controlling peak pressures within acceptable ranges (12-18 bar).
2Stress or pressure
If a permanently available dead space is used to reduce maximum compression, then peak pressures are reduced, but air delivery is reduced especially at low charging pressure
Solution Approach 1:
Instead of a permanently available dead space, the invention uses an adjustable valve unit that can dynamically change the valve cross section. This allows the system to optimize the balance between compression ratio and air delivery at different operating conditions, maintaining high air delivery at low charging pressures while controlling peak pressures through multi-stage compression.
Solution Approach 2:
The valve cross section is made adjustable, allowing the system to change the flow resistance parameter dynamically. This enables optimization of air delivery at low charging pressures while the multi-stage compression handles peak pressure reduction, eliminating the need for a permanently available dead space that would compromise air delivery.
3Productivity
If large valves are used to cope with high volumetric flows, then air throughput is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The compression process is segmented into two stages, which allows the use of smaller valves in each stage compared to a single-stage compressor handling the same total volumetric flow. The first stage valve handles lower volumetric flow at lower pressure, and the second stage valve handles the remaining flow, reducing the overall valve size requirement.
Solution Approach 2:
The adjustable valve unit allows optimization of valve size based on actual operating conditions. By dynamically adjusting the valve cross section, the system can maintain efficient air throughput with smaller valves rather than requiring oversized valves to handle peak volumetric flows continuously.
4Productivity
If the compressor is designed for high air delivery at high engine speeds, then productivity is improved, but energy consumption increases at low engine speeds
Solution Approach 1:
The adjustable valve unit enables the compressor to dynamically adapt its characteristics to match the actual air demand at different engine speeds. At low engine speeds, the valve can be adjusted to reduce flow resistance and optimize air delivery for specific applications (e.g., container change operation), avoiding excessive energy consumption while meeting the reduced but still important air demand.
Solution Approach 2:
The system changes operational parameters (valve cross section, compression ratio) based on engine speed and air demand conditions. This allows optimization of the balance between air delivery and energy consumption across the entire operating range, from low engine speeds with reduced demand to high engine speeds with maximum demand.
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
The solution reduces peak pressures, allows for smaller valve design, and achieves energy economy by adjusting air delivery based on engine speed and air requirements, ensuring efficient air supply and reduced energy consumption.
Implementation Method 1
a piston chamber (14), a dead space (16) and a valve unit (18) for engaging the dead space (16). The valve unit (18) is formed such that the air volume which is delivered by the charged compressor (10) can be reduced to a value which differs from zero by engaging the dead space (16)
Data Source
AI summary
A supercharged compressor and method of operating the compressor supplies a commercial vehicle with compressed air. The compressor includes a piston chamber, a dead space or clearance volume and a valve unit for switching the clearance volume. The valve element is configured such that the air volume supplied by the supercharged compressor can be reduced to a value that is different from zero by activating the clearance volume.