Refrigerant Filling Equipment for Vehicle Assembly
Introduction
Fluid filling is one of the final process steps on a vehicle assembly line, and it has a direct effect on whether a vehicle can be started, tested and shipped without rework. Coolant and antifreeze circuits are particularly sensitive because the fill volume, the dissolved air in the fluid and the final liquid level all influence heat management during engine run-in and end-of-line testing.
Refrigerant filling for vehicle assembly is often discussed together with coolant filling, because both processes depend on the same principle: remove air and moisture from a closed circuit, verify that the circuit is tight, then introduce the fluid under controlled conditions. A vacuum-based filling machine applies that principle to antifreeze and coolant circuits. This article reviews how such equipment works, which features matter to production and process engineers, where it is applied in vehicle assembly, and how to evaluate a supplier for a specific line.
Product Overview
The Antifreeze Vacuum Filling Machine is an automated station for coolant and antifreeze filling on automotive production and assembly lines. It combines vacuum evacuation, leak testing, pressure filling and back suction in a single cycle, and it is designed to deliver a stable liquid level after filling rather than a level that drops once the vehicle moves to the next station.
The machine is controlled by a PLC system that automates the complete filling process. It handles a filling volume range of 1–400 L, which allows the same equipment platform to serve different circuit sizes and vehicle programs. Filling pressure is adjustable between 1 and 4 bar, and the maximum filling speed is 60 L/min. Filling precision is stated as ±0.5%, with liquid level accuracy of ±2 mm and a measurement display range of 0.0–999.9 L.
For process engineers, the relevant point is not only the fill accuracy but the sequence: the machine does not simply push fluid into the circuit. It prepares the circuit first, verifies tightness, and then fills. This is what makes the station suitable for automated coolant and antifreeze filling applications where rework or fluid loss downstream is costly.
Working Principle
The filling cycle follows a defined sequence that can be summarized in four stages.
1. Vacuum Evacuation
The system first performs vacuum evacuation of the circuit. Removing air from the cooling system creates the conditions for a complete fill and reduces the risk of trapped air pockets that would later affect cooling performance or cause level fluctuation.
2. Leak Testing Under Vacuum and Pressure
After evacuation, the machine performs leak testing under vacuum and pressure conditions. The relevant specifications are a negative pressure leak rate of ≤0.5 mbar / 60 s and a positive pressure leakage value of<1.4 g/year. These two checks allow the station to confirm circuit tightness before fluid is introduced, so a leaking circuit is identified before it is filled.
3. Secondary Vacuum and Pressure Filling
Once system tightness is confirmed, a secondary vacuum is created before the coolant is introduced under controlled pressure. Filling pressure can be set within the 1–4 bar range, and the maximum filling speed is 60 L/min. Introducing fluid into a partially evacuated circuit reduces the amount of entrained air compared with gravity or simple pressure filling.
4. Venting and Back Suction
When the filling pressure reaches equilibrium, the system automatically vents to atmospheric pressure and performs back suction to remove excess coolant. This step is what produces the specified liquid level and prevents the coolant level from dropping after filling. Liquid level accuracy is specified at ±2 mm, which matters when the level is checked at a later station or after the engine has been run.
Process note: The full cycle integrates vacuum evacuation, leak testing, pressure filling and back suction. Because these steps run in one automated sequence, the station does not depend on an operator to decide when the circuit is ready for fluid.
Key Features
PLC-controlled automated cycle — the complete coolant filling process, from evacuation to back suction, is automated by the control system.
Combined vacuum and pressure leak testing — negative pressure leak rate of ≤0.5 mbar / 60 s and positive pressure leakage of<1.4 g/year confirm circuit tightness before filling.
Secondary vacuum before filling — fluid is introduced after a second vacuum is created, reducing entrained air in the circuit.
Adjustable filling pressure — the filling pressure range of 1–4 bar allows the process to be matched to different circuits.
Back suction for stable liquid level — automatic venting to atmospheric pressure and back suction remove excess coolant and achieve the specified level.
Wide filling volume range — 1–400 L covers small and large coolant circuits on the same equipment platform.
Filling precision of ±0.5% and liquid level accuracy of ±2 mm — supports repeatable fill results across a production run.
Measurement display range of 0.0–999.9 L — gives operators and process engineers a clear readout of the filled volume.
Vacuum pump capacity of 40–65 m³/h — matched to the evacuation requirements of the filling cycle.
Customizable equipment dimensions — the standard footprint is 1800 × 1000 × 800 mm and can be adapted to line layout requirements.
Applications
The machine is intended for automated coolant and antifreeze filling applications on automotive production and assembly lines. Typical positions in the plant include:
Vehicle final assembly — coolant filling at the end of the trim and final line, before engine start and end-of-line testing.
Powertrain manufacturing — filling of engine and powertrain cooling circuits where a defined fill volume and a verified tight circuit are required.
New energy vehicle assembly — thermal management circuits on electrified vehicles, which also rely on a correctly filled and leak-tested coolant loop. Related new energy cooling systems also require controlled coolant filling.
Automotive component production — filling and leak testing of cooling modules and related components before delivery to the vehicle assembly plant.
Because the filling volume range extends to 400 L and the equipment dimensions can be customized, the same machine concept can be applied to different circuit sizes and different station layouts rather than being limited to a single vehicle program.
Benefits
The value of a vacuum-based filling station in vehicle assembly comes from combining several process steps that would otherwise be handled separately or manually.
Improved process consistency — filling precision of ±0.5% and liquid level accuracy of ±2 mm support repeatable results from vehicle to vehicle.
Stable liquid level after filling — back suction and automatic venting reduce the risk of the coolant level dropping after the vehicle leaves the station.
Leak detection before filling — vacuum and pressure leak testing identify a non-tight circuit before coolant is introduced, which avoids filling a circuit that will leak.
Reduced entrained air — evacuation and secondary vacuum before filling limit the air left in the cooling system.
Production integration — the PLC-controlled cycle can be embedded in an automated assembly line sequence rather than operated as a standalone manual task.
Traceable fill data — the measurement display range of 0.0–999.9 L gives a readable fill volume for the station record.
These benefits are process-level effects of the machine design described above. They are not tied to a specific percentage improvement, because the actual result depends on the vehicle circuit, the line takt time and how the station is integrated.
Why Choose KINMARK
KINMARK (Jinan Kinmark Technology Co., Ltd.) was founded in 1996 and is based in the high-tech development zone in eastern Jinan. The company develops and manufactures marking and traceability systems, fluid filling systems, servo press systems and robot automation systems. It is recognized as a Shandong "Gazelle" enterprise and a "Specialized and Sophisticated" enterprise.
The company began with marking machines and expanded into automotive intelligent automation equipment. Its three main product series are marking and traceability, servo press-fitting, and fluid conveying and filling. Its business covers complete vehicles, powertrain, automotive components, construction machinery, home appliances, new energy, electronic communications and rail transit.
For fluid filling projects, the relevant capabilities are:
Automotive focus — long-term cooperation with vehicle manufacturers and suppliers in the automotive industry.
Fluid filling experience — filling equipment delivered for automotive production lines, including follow-along filling projects.
Service network — offices and maintenance centers in Shanghai, Beijing, Guangzhou, Changchun, Wuhan and Chongqing.
Support scope — the complete machine is covered by a 12-month warranty, with professional technical support and long-term maintenance service.
After-sales response — efficient after-sales support, remote diagnosis and technical assistance to support continuous operation.
Installation and commissioning — engineers provide equipment installation, commissioning and operator training to help customers start production smoothly.
When evaluating refrigerant filling and coolant filling equipment for vehicle assembly, the practical questions are whether the machine can hold the required fill accuracy, whether leak testing is integrated into the same cycle, and whether the supplier can support the station after installation. The specifications and support scope above are the points to compare against the line requirements.
Frequently Asked Questions
What is the difference between vacuum filling and pressure filling for coolant circuits?
Pressure filling introduces fluid into a circuit that still contains air. Vacuum filling first evacuates the circuit, then introduces fluid under controlled pressure. The Antifreeze Vacuum Filling Machine uses evacuation, a secondary vacuum and pressure filling within a range of 1–4 bar, followed by venting and back suction. This sequence reduces entrained air and helps achieve a stable liquid level after filling.
How is leak testing integrated into the filling cycle?
The machine performs leak testing under vacuum and pressure conditions after the initial evacuation and before the coolant is introduced. The specified values are a negative pressure leak rate of ≤0.5 mbar / 60 s and a positive pressure leakage of<1.4 g/year. Because the test happens before filling, a circuit that does not pass the test is identified before fluid is added.
What filling volume and speed can the machine handle?
The filling volume range is 1–400 L, with a maximum filling speed of 60 L/min. Filling pressure is adjustable from 1 to 4 bar. Filling precision is ±0.5%, liquid level accuracy is ±2 mm, and the measurement display range is 0.0–999.9 L. The wide volume range allows the same equipment platform to be used for different circuit sizes.
Why does the machine use back suction after filling?
Once the filling pressure reaches equilibrium, the system automatically vents to atmospheric pressure and performs back suction to remove excess coolant. This is what achieves the specified liquid level and prevents the coolant level from dropping after filling, which is important when the level is checked at a later station or after the engine has been run.
What support is provided after the equipment is installed?
The complete machine is covered by a 12-month warranty, with professional technical support and long-term maintenance service. KINMARK provides efficient after-sales support, remote diagnosis and technical assistance. Engineers also provide equipment installation, commissioning and operator training to help customers start production smoothly, supported by offices and maintenance centers in several cities.
Conclusion
Refrigerant filling for vehicle assembly and coolant filling share the same process logic: prepare the circuit, verify it is tight, fill it under controlled conditions, and finish with a stable liquid level. The Antifreeze Vacuum Filling Machine applies that logic in a single PLC-controlled cycle that combines vacuum evacuation, vacuum and pressure leak testing, secondary vacuum, pressure filling and back suction.
For production and process engineers, the specifications that matter in evaluation are the filling volume range of 1–400 L, filling pressure of 1–4 bar, maximum filling speed of 60 L/min, filling precision of ±0.5%, liquid level accuracy of ±2 mm, and the leak test values of ≤0.5 mbar / 60 s under negative pressure and<1.4 g/year under positive pressure. These parameters, together with the ability to customize equipment dimensions and integrate the station into an automated assembly line, determine whether the machine fits a specific vehicle program. KINMARK's fluid filling experience, service network and installation and commissioning support are the practical factors to weigh alongside the technical data.
If you're interested in any of the equipment mentioned in this article, feel free to contact our sales engineers for detailed product information and customized technical solutions.