Procedure for retrofitting a bus airconditioning system
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Solution Overview
Problem
Existing bus air conditioning systems face issues with compressor design due to exposure to vibrations and heat, leading to potential leaks and the need for oversized compressors to maintain cooling performance, especially at low engine speeds.
Innovation Solution
The method involves replacing the diesel engine-mounted compressor with an electric generator, which powers an external electric compressor, allowing for a more compact design and improved control over cooling capacity, using a semi-hermetic compressor driven by an electric motor and regulated by an inverter for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the compressor is designed to be extremely powerful to deliver noticeable cooling capacity at idle speed, then cooling capacity at low engine speed is improved, but compressor size and capacity control become problematic
Solution Approach 1:
The patent applies dynamics by making the compressor capacity adjustable through an inverter that controls the electric motor's speed. The compressor capacity can be dynamically adapted to match actual cooling demands, allowing a smaller compressor to provide sufficient cooling at idle speed while preventing excessive cooling at high engine speeds. This resolves the contradiction by enabling continuous capacity adjustment rather than relying on a fixed oversized design.
2Area of stationary object
If the compressor is arranged in the diesel engine installation space, then space utilization is improved, but exposure to vibrations and heat causes leaks and reliability issues
Solution Approach 1:
The patent extracts the compressor from the problematic diesel engine installation space and relocates it to a separate mounting location. By removing the compressor from the engine compartment, it is no longer exposed to the harmful vibrations and high temperatures that cause leaks and reliability issues. The generator remains in the engine installation space, maintaining space utilization, while the compressor operates in a more favorable environment.
3Device complexity
If a belt drive connects the compressor to the diesel engine, then mechanical power transmission is simplified, but disruptive influences from the engine affect the compressor
Solution Approach 1:
The patent replaces the mechanical belt drive connection with an electrical power transmission system. The generator converts mechanical energy from the diesel engine into electrical energy, which then drives the electric motor connected to the compressor. This substitution eliminates the direct mechanical coupling that transmits vibrations and heat to the compressor, while still providing reliable power transmission through the electrical system.
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 enables a more compact and efficient air conditioning system with reduced energy consumption, lower maintenance needs, and the ability to use environmentally friendly refrigerants like CO2, providing superior cooling performance even at low engine speeds with minimal design intervention.
Implementation Method 1
arranging or attaching an electric generator in a accommodation space arranged in a diesel engine of a bus... wherein the compressor is driven by the electrical power generated by the generator
Implementation Method 2
arranging or attaching a compressor, which has an electric motor and a compression device driven by the electric motor for compressing refrigerant
Implementation Method 3
a compression device driven by the electric motor for compressing refrigerant
Data Source
Figure 1
AI summary
A bus air-conditioning arrangement with a compressor for compressing refrigerant, wherein the compressor has an electric motor and a compression device, which is driven by the electric motor, for compressing refrigerant, wherein the bus air-conditioning system furthermore has an electric generator which has dimensions such that said generator can be fitted in a receiving space, which is provided for a compressor and which is arranged in a driving motor of a bus or in an installation space for the driving motor of the bus, wherein the generator is driveable by the driving motor, in particular by means of a belt drive, and wherein the electric motor of the compressor is driveable by electrical power which the generator generates, and a method for producing same.