Compressor description by Ralkin

BITZER ROADSTAR 4GFC Compressor Analysis

The BITZER ROADSTAR family consists of optimized 4- and 6-cylinder aluminum compact compressors developed for the special requirements of vehicle air-conditioning. Designed to cope with the challenges of all climatic zones and mobile operating conditions, this series offers a compact design, low weight, optimized drive gear, and high efficiency, ensuring proven reliability and improved ease of maintenance.

Model Identification

• 4: Indicates a 4-cylinder configuration.
• G: Indicates the displacement volume within the 4-cylinder series (744 cm³).
• FC: Indicates the ROADSTAR series family optimized for vehicle applications.
• (Y): Optional designation (often referring to specific clutch or mounting configurations, though standard features are listed below).

Technical Features

• Refrigerant: Optimized for R134a; other refrigerants available upon request.
• Shaft Seal: Patented design with a secondary oil barrier; easily accessible and exchangeable.
• Drive Parts: Features smooth running due to the four/six cylinder principle and dynamic mass balance, low friction losses from a surface-hardened drive shaft and hard chrome-plated piston rings, and reinforced connecting rods geometry.
• Cylinder Liners: Exchangeable and particularly wear-resistant.
• Bearings: Combined roller and sleeve bearings designed for extreme loads at high speed with minimum axial clearance.
• Lubrication: Reversible oil pump system.
• Oil Management: Minimum oil carry-over rate due to an internal oil separator.
• Valves: Flapper valves made of impact-resistant spring steel, an integrated pressure relief valve, and high-efficiency working valves.
• Shaft: Tapered shaft end for precise, safe, and low-vibration power transmission.
• Mounting: Exchangeable position of the shut-off valves with optional spacer flanges enables flexible mounting in tight spaces. 4- and 6-cylinder models share identical fixing points and shaft height.

Specifications & Data

• Compressor Type: 4GFC
• Number of Cylinders: 4
• Cylinder Volume: 744 cm³
• Displacement:
  • At 1450 rpm: 64.7 m³/h
  • At 3000 rpm: 133.9 m³/h
• Weight: 34.0 kg (Note: Standard bottom plate adds 1 kg)
• Oil Charge: 1.5 dm³ (Note: Standard bottom plate adds 1 dm³)
• Capacity Control: Available as an accessory with steps of 100% and 50% (or 66%/33% for 6-cylinder models).
• Speed Range: 500 – 3500 min⁻¹
• Note: The compressor is optimized for a vehicle engine with variable speed. Do not exceed the maximum speed (3500 rpm), even at high idle.
• Pipe Connections:
  • Discharge Line: 35 mm (1 3/8 inch)
  • Suction Line: 35 mm (1 3/8 inch)
• Magnetic Clutch (Accessory): Compatible with LINNIG LA16 or LANG KK73.1.