Compressor Valve Device for Utility Vehicle Air Supply
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Solution Overview
Problem
Commercial vehicle compressors face extreme mechanical and thermal loads due to increased air requirements at low engine speeds and excessive air delivery at high speeds, particularly during engine braking, where a shutdown is undesirable but necessary to prevent material damage.
Innovation Solution
A compressor design with a gear transmission ratio of less than one and a valve device that allows the addition of dead space to reduce air flow and compression degree, thereby reducing thermal and mechanical loads by adjusting the valve cross-section and switching on additional dead space volumes as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a decreasing transmission ratio is used to increase air delivery at low engine speeds, then the air requirement at low speeds is satisfied, but extreme mechanical and thermal loads occur at high engine speeds
Solution Approach 1:
The patent applies dynamics by making the dead space volume adjustable rather than fixed. The control device dynamically switches the dead space between connected and disconnected states based on operating conditions (engine speed, air demand). At low speeds, the dead space is disconnected to maximize air delivery. At high speeds, the dead space is connected to reduce compression ratio and thereby reduce mechanical and thermal loads on compressor components.
Solution Approach 2:
The patent changes the physical parameter of dead space volume by switching it between two states (connected and disconnected). This parameter change effectively alters the compression ratio of the compressor. When the dead space is connected, the compression ratio decreases, reducing the work done during compression and consequently reducing thermal and mechanical loads. When disconnected, the compression ratio increases, maximizing air delivery efficiency.
2Strength
If the compressor is shut down to protect from material damage at high speeds, then mechanical loads are reduced, but air availability for service brake during engine braking is lost
Solution Approach 1:
Instead of completely shutting down the compressor, the system dynamically adjusts the dead space connection state. During engine braking when air is needed for service brake, the control device keeps the dead space disconnected to maintain air delivery capability while still providing some load reduction. The compressor remains operational but operates under reduced load conditions, ensuring both material protection and air availability for safety-critical functions.
Solution Approach 2:
The patent applies partial action by partially reducing the compression ratio through dead space connection rather than completely stopping the compressor. This partial reduction is sufficient to protect materials from excessive loads while maintaining enough compression capability to deliver air for service brake during engine braking. The solution avoids the extreme of complete shutdown while still achieving load protection.
3Temperature
If dead space is switched on to reduce compression and thermal load, then thermal load is reduced, but air delivery capacity decreases
Solution Approach 1:
The system dynamically switches the dead space connection state based on real-time operating conditions. The control device monitors engine speed, air demand, and thermal load levels. When thermal load becomes excessive at high engine speeds, the dead space is connected to reduce compression temperature. When air delivery capacity is prioritized at low speeds or moderate loads, the dead space is disconnected to maximize productivity. This dynamic switching resolves the contradiction by adapting to different operational requirements.
Solution Approach 2:
The dead space switching operates periodically based on operating cycle variations. During transient high-speed conditions that generate excessive thermal load, the dead space is connected temporarily. During normal operating ranges where air delivery is critical, the dead space remains disconnected. This periodic switching based on operational phases allows the system to optimize between thermal management and air delivery capacity at different times.
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 effectively reduces mechanical and thermal stresses on compressor components, allows for energy-saving operation by minimizing air delivery when not needed, and protects the compressor from excessive loads, especially during high-speed engine braking.
Implementation Method 1
the compressor is driven by the drive motor via a gear with a transmission ratio of less than one
Implementation Method 2
the valve device is designed in such a way that, by switching on dead space, the conveyed by the compressor Air flow can be reduced to a value other than zero
Implementation Method 3
The addition of dead space reduces the degree of compression that can be achieved by the compressor during a compression phase. Since the heat generated during compression is correlated to the degree of compression, reducing the maximum compression also reduces the heat generated during a compressor pumping cycle
Data Source
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AI summary
The invention relates to a compressor (10) for supplying compressed air to a utility vehicle (12), said compressor comprising a drive engine (20), wherein the compressor (10) is driven by the drive engine (20) via a transmission (26) having a transmission ratio that is less than one and comprises a piston chamber (14), a clearance volume (16) and a valve device (18) for switching the clearance volume (16). According to the invention, the valve device (18) is configured in such a manner that the air stream supplied by the compressor (10) can be reduced to a value that is different from zero by activating the clearance volume (16). The invention further relates to a method for controlling a compressor (10) for supplying compressed air to a utility vehicle (12).