I. Composition of the Air Conditioning System & Introduction to Components

Composition of the Air Conditioning System:

Automotive air conditioning systems typically comprise the following components: compressor, condenser, receiver-drier, expansion valve, evaporator, blower fan, throttle valve, and ventilation system.

Introduction to Air Conditioning System Components—HVAC Air Conditioning Assembly:

The air conditioning unit employs mode selection dampers to direct cold or warm airflow to specific vents, such as footwell, face, or defrost outlets. Temperature control dampers blend cold and warm air to achieve the desired outlet temperature. The internal/external air mix damper regulates the proportion of cabin and external air, directly influencing temperature, air quality, and defrosting/demisting functionality.

Introduction to Air Conditioning System Components—Condenser:

Function of the condenser: to cool the refrigerant.

The condenser integrated with a dryer, wherein a liquid receiver dryer is installed at the end of the refrigerant circuit within the condenser, facilitates simplified air conditioning system design and enhances the reliability of the refrigeration system.

Introduction to Air Conditioning System Components—Compressor:

The compressor serves as the ‘heart’ of the air conditioning system, analogous to the engine's role in a vehicle—it is the driving unit.
In conventional air conditioning systems, the compressor is driven via an engine belt.
The compressor must exclusively draw in and expel gaseous refrigerant.
Its internal mechanism contains numerous moving parts, necessitating sufficient lubricating oil to lubricate these components.

Introduction to Air Conditioning System Components—Air Conditioning Piping:

The air conditioning piping system comprises key components such as aluminium tubing, flexible hoses, and pipe fittings, which collectively connect all elements of the air conditioning system. Aluminium tubing and flexible hoses are tightly joined via crimping techniques, though minor variations in crimp dimensions may exist between different models and manufacturers. To mitigate potential damage from engine vibration, flexible rubber hoses are employed for the lines connecting the compressor's suction and discharge ports. Their flexible design effectively absorbs vibrations, enhances system sealing integrity, and extends the service life of the piping. Many manufacturers have also developed nylon air conditioning hoses, which are utilised in mass-produced vehicle models.

II. Refrigeration Principles of Air Conditioning Systems

The operational principle of refrigeration systems relies upon the continuous vaporisation and liquefaction of refrigerant. The entire refrigeration cycle comprises four distinct operational stages: compression, condensation and heat release, throttling, and evaporation. During compression, the low-temperature, low-pressure refrigerant gas processed by the evaporator is compressed by the compressor into a high-temperature, high-pressure gas, which is then delivered to the condenser. During the condensation and heat release stage, the high-temperature, high-pressure refrigerant gas gradually condenses into a liquid while releasing heat. The subsequent throttling process, via the expansion valve, transforms the refrigerant from a high-pressure to a low-pressure state. Finally, the evaporation process occurs within the evaporator, where the refrigerant absorbs a significant amount of heat before re-entering the compressor, thereby achieving the cooling of the vehicle's interior.

III. Precautions for Air Conditioning Refrigerant Pipe Assembly

When installing air conditioning pipework and connecting components, the method of fitting and tightening joints is critical.
When removing pipe plugs, first inspect the O-ring for integrity and apply lubricant evenly to its sealing surface. For threaded pipe joints, also apply lubricant evenly to the external threads. When applying lubricant, observe the following points: 
The lubricant applied must be compressor-grade lubricant, PAG or equivalent grade.
Lubricate threaded sections to prevent seizing after tightening.
To prevent moisture absorption, promptly reseal lubricant containers after use.
To maintain internal cleanliness of system components such as piping, remove plugs only immediately prior to installation. Refit promptly; do not leave exposed to air for extended periods.  
Clamp-type joint connection: Insert the lubricated clamp plate's blind hole vertically through the double-ended stud. Simultaneously insert the clamp joint vertically into the corresponding mounting hole. Avoid tilting during insertion to prevent O-ring damage. Once seated with parallel faces, hand-tighten the nut until resistance is encountered. Subsequently, use a torque ratchet or wrench to tighten the bolt to specification, marking the tightened position. The tightening torque for M8 nuts is 15–20 N·m; for expansion valve nuts (M6), it is 6–10 N·m. 
Threaded joint connection. Insert the lubricated sealing ring end into the threaded joint end. Align and insert vertically until the front face of the plug head contacts the threaded joint. Hand-tighten the nut, then secure the threaded joint end with an open-end spanner. Tighten the nut end using a torque wrench, marking the tightened position (see figure below). Tightening torque specifications: High-pressure pipe fitting (M16×1.5 threaded joint): 12–15 N·m Low-pressure pipe fitting (M24×1.5 threaded joint): 30–35 N·m.

Note: When tightening threaded joints, it is essential to use two spanners simultaneously to avoid deformation of the pipework.

Connection of dual clamp joints. First position the end of the high-pressure clamp within the fork slot of the low-pressure clamp. Align and push the compressor interface in parallel. Once the clamps are flattened, inspect the O-ring position for misalignment or extrusion. Hand-tighten the bolts until resistance is encountered, then use a torque ratchet or wrench to tighten to specification, marking the tightened position (see figure below). The tightening torque for the compressor tail bolts (M10×1.25×35) is 20–30 N·m.

Supplementary Notes on Air Conditioning Pipe Installation:

Minor damage to O-rings during pipe installation may compromise sealing integrity, leading to refrigerant leakage.
Following installation, verify that pipes do not interfere with or exhibit free movement relative to surrounding vehicle components. Address any friction or interference promptly through adjustment, and secure pipes prone to free movement with appropriate fastenings.
Moving components such as the engine throttle cable and oil dipstick must never be bundled together with air conditioning piping. This prevents abrasion of the air conditioning lines, which could lead to refrigerant leakage.

The EU’s stringent carbon emission regulations are driving the acceleration of electrification, yet Europe faces a severe shortage of domestic production capacity for batteries, electric drive systems and smart components, coupled with slow technological advancement and a reliance on external supplies. In 2024, China’s exports of automotive components totalled US$93.43 billion, with Europe representing the core growth market.

I.Why accelerate now?

From ‘export products’ to ‘local roots’—the EU’s high tariffs (up to 45.3%), local content requirements (70% local production for non-battery components in electric vehicles), and the New Battery Act (covering carbon footprint, traceability and recycling) have effectively brought an end to the old model of ‘Made in China → Exported to Europe’, with local manufacturing now becoming a prerequisite for market access.

Maturity of China’s Supply Chain + Cost Advantage China possesses the world’s most comprehensive new energy vehicle supply chain, with manufacturing costs 20–30% lower than in Europe. Furthermore, it has established a technological lead in areas such as battery energy density, autonomous driving algorithms and sensors, which aligns with European carmakers’ core objectives of reducing costs and accelerating their transition.

II. From Supporting Roles to Diverse Penetration

• Traditional supply chain exports

From the export of complete vehicles to the subsequent export of components, serving the European factories of Chinese car manufacturers (such as BYD and NIO). This model is characterised by passive supply, low value-added and a focus on trade. In the early stages, small and medium-sized component manufacturers exported items such as wheel rims, interior fittings and standard parts.

• Establishing production capacity

Establishing factories in Europe, recruiting locally and serving local car manufacturers, thereby entering the supply chains of major players such as BMW, Mercedes-Benz, Audi, Volkswagen and Stellantis, and transitioning from a ‘Chinese supplier’ to a ‘local European Tier 1 supplier’.

Using Central and Eastern Europe (Hungary, Slovakia and Poland) as a bridgehead (due to low costs, favourable policies and proximity to Western Europe), whilst establishing R&D centres in Western Europe (Germany and Spain).

• Technology transfer

Technology licensing + joint ventures + solution provision: earn technology fees and long-term royalties without building factories, and secure a position at the high end of the value chain.

• Ecological permeation

With a fully integrated presence spanning R&D, testing, after-sales and local partnerships, we have evolved from a ‘parts supplier’ to a ‘technology partner’, forging close ties with European car manufacturers as they undergo transformation.

BYD’s European headquarters in Hungary (comprising sales, after-sales, R&D and testing) collaborates on research with local universities.

III. Key Challenges

• Compliance barriers

EU REACH, PFAS restrictions and the Battery Regulation: with extremely stringent requirements regarding chemical traceability, carbon footprints and recycling systems, compliance costs for small and medium-sized suppliers are soaring, and they risk being forced out of the market.

Data compliance: Localised storage of autonomous/intelligent driving data and strict privacy protection; algorithms exported overseas must comply with EU regulations.

• Cost and operational barriers

The cost of setting up a factory in Europe is two to three times that in China; labour costs are high, and unit production costs rise by 15–20 per cent, which must be offset through automation and lean manufacturing.

Strong trade unions and strict employment regulations: redundancies are difficult to implement, benefits are generous, and cross-cultural management presents significant challenges.

Domestic giants (Bosch, Continental and ZF) continue to dominate the high-end chassis and traditional powertrain components markets, drawing on a century of technical expertise.

Japanese and South Korean companies (Samsung SDI and LG Energy Solution) have a clear first-mover advantage, and competition in the battery sector is fierce.