Electric Air Compressor Speed Control for Demand-Matched Efficiency
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Solution Overview
Problem
Conventional air compressors in heavy-duty vehicles driven by internal combustion engines lack control over compressor speed, leading to inefficient compressed air production and energy wastage, while electric motor-driven compressors are energy-intensive.
Innovation Solution
A method to control the rotational speed of an electric motor-driven air compressor by determining efficient operating speeds based on pneumatic power production and consumption rates, using a control unit to adjust the compressor speed for optimal efficiency and energy savings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the air compressor is driven by an internal combustion engine, then the compressor speed depends on the engine speed, but the compressor cannot be controlled and runs at low efficiency speeds causing energy wastage
Solution Approach 1:
The patent replaces the mechanical coupling between the internal combustion engine and air compressor with an electric motor-driven system. This substitution enables independent control of compressor speed from engine speed, allowing the compressor to operate at optimal efficiency points regardless of engine operating conditions, thereby resolving the contradiction between operational control and energy consumption.
Solution Approach 2:
The patent implements dynamic speed control of the electric motor-driven compressor based on real-time monitoring of compressed air storage levels and consumption rates. The system continuously adjusts compressor speed to match actual demand, enabling operation at peak efficiency points while avoiding energy wastage from running at suboptimal speeds, thus resolving the control versus energy consumption contradiction.
2Ease of operation
If the air compressor is driven by an electric motor independent of the propelling motor, then speed control is enabled, but energy consumption increases significantly
Solution Approach 1:
The patent applies partial action by operating the electric motor-driven compressor only when and where needed, rather than continuously. The system monitors compressed air storage levels and activates the compressor only when storage falls below threshold levels, and adjusts motor power output to match actual consumption rates. This selective operation reduces overall energy consumption while maintaining speed control capabilities when required.
Solution Approach 2:
The patent implements periodic operation of the compressor based on the cyclic pattern of compressed air consumption and storage level fluctuations. The system activates the compressor in periodic cycles to recharge storage tanks, rather than running continuously. This periodic action pattern reduces total energy consumption while maintaining the ability to control compressor speed during active periods to operate at efficient points.
3Reliability
If the compressor runs continuously to meet air demand, then air supply is maintained, but the compressor operates at inefficient speeds wasting energy
Solution Approach 1:
The patent implements a feedback control system that continuously monitors compressed air storage levels, consumption rates, and compressor operating conditions. Based on this feedback, the system dynamically adjusts compressor speed and activation timing to maintain reliable air supply while operating only when necessary and at optimal efficiency points, thereby resolving the contradiction between supply reliability and energy wastage.
Solution Approach 2:
The patent enables the compressed air system to self-regulate by monitoring its own storage levels and consumption patterns. The control system automatically determines when compression is needed and adjusts operating parameters without external intervention, allowing the system to maintain reliable supply while minimizing energy wastage through intelligent, demand-based operation at efficient speed points.
Data Source
AI summary
A method for controlling the rotational speed (S) of an electric motor driven air compressor (2) that supplies compressed air to a pneumatically operated system (5) of a vehicle (1), characterized by the preliminary steps of: a) determining the efficiency (e) of the air compressor (2) for different values (Si) of the rotational speed (S) of the air compressor (2), the efficiency (e) of the air compressor (2) corresponding to the ratio between the pneumatic power (PI) produced by the air compressor (2) and the power (PO) given to the air compressor (2); b) determining one or several specific values (S2, S4) among said different values (Si), for which the efficiency (e) of the air compressor (2) is higher than a threshold value (emin) and/or comparatively higher than those determined for values (SI, S3) close to said specific value(s) (S2, S4); the preliminary steps a) and b) being preferably implemented only once; and characterized by the further repetitive steps of: c) determining the air consumption rate of the pneumatically operated system (5) receiving compressed air from the air compressor (2); d) determining a minimum rotational speed (Smin) of the air compressor (2) to obtain an air production rate of the air compressor (2) that is equal or substantially equal to said determined air consumption rate; e) determining if the specific value or one of the specific values (S2, S4) is greater than said determined minimum rotational speed (Smin); f) if no specific value is greater than said determined minimum rotational speed (Smin), controlling the rotational speed (S) of the air compressor (2) based on said minimum rotational speed (Smin); g) if only one specific value (S4) is greater than said determined minimum rotational speed (Smin), controlling the rotational speed (S) of the air compressor (2) based on said only one specific value (S4); h) if a plurality of specific values (S2, S4) is greater than said determined minimum rotational speed (Smin), determining the specific value (S2) with the best efficiency among said plurality of specific values (S2, S4) and controlling the rotational speed (S) of the air compressor (2) based on said specific value (S2) with the best efficiency.