Truck refrigeration units, bus air conditioning system
  • Sub-engine Bus Air Conditioner
  •  Sub-engine Bus Air Conditioner

DD Series Sub-Engine Bus Air Conditioner

  • Model: • DFDD
  • Cooling Capacity: • 32700~41300Kcal/h
  • Driven Type: • Sub-engine
  • Application: • 12-14 meter Bus

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DD Series Bus Air Conditioner System Introduction

DD as the power pack of the bus air conditioner, the rooftop unit is powered by a sub-engine, special design for the buses which is lack of power to support the working of air conditioning system. Guchen DD series bus air conditioner can equip with other vehicle engine driven ac units, such as equip with BD bus air conditioner, SD or PD series. When equip DD series bus air conditioner, the ac units will not rely on bus engine to generate cold air, that is to say, even the bus stops on the half way, the cold air will not stop! So DD series are also called as “independent bus air conditioner units”.

DD Series Bus Air Conditioner System Features

1.Independent compressor drive, stable system pressure, not interfered by the main motor and with both quality of cooling and driving.
2.Use engine with high quality to ensure low noise, less fuel consumption and match large displacement compressor with strong cooling output.
3.Perfect protection function for voltage, coil temperature, system pressure, temperature of motor and oil pressure.
4. Humanisti rear starter design, rated power is 2.3 kW, rated voltage is 12V, hermetic structure, easy and fast operation and maintenance.
5. Bus air conditioner’s compressor is driven by this DFDD sub-engine, power input is very stable, which not affected by the vehicle engine, low noise, fuel saving, big displacement compressor, make the bus A/C have a strong cooling output

Main Structurer / Accessories of The Engine Include The following Parts: 

main accessories of Sub-engine Bus Air Conditioner 1

1 Radiator Fill  2 Lift Point  3 Air cleaner  4 Compressor  5 Fan of Radiator  6 Generator  7 Starter  8 Muffler  9 Generator for air conditioning 


main accessories of Sub-engine Bus Air Conditioner 2

1 Sigh Glass of Compressor  2 Oil Filter  3 Lift Point  4 Radiator  5 Control Box  6 Water Separator  7 Fuel Filter  8 Fuel Solenoid  9 Generator 

Main Parameter of Diesel and the requirements of its accessory 


◆ Suction and exhaust system 

1. The diesel is equipped with muffler, the exhaust tail pipe is downward fitted, and the d = 57.2mm 

2. Air cleaner is fitted in the suction pipe, d = 50mm 

3. system is fitted with inlet air heater, DC 12v/400w-15S 


◆ Suspension system 

Front and rear suspension bracket is provided by user, installation dimension please refer the outline dimension 


◆ Cooling system 

Use suction type system plastic fan, with 8 pieces fan blades, 

Water tank is provided 

Water outlet of the engine is fitted upward, d = 28mm 

Water pump inlet is fitted left side, (viewed from the end of the fan blade) d = 28 mm 


◆ Fuel system 

1. high pressure fuel pump: MP4 

2. Power output control: cut off the electricity and shut up the fuel supply. 

3. the engine is equipped with fuel feeding pump 


◆ Lubrication system 

Oil capacity of engine is about 3.4~7.4 liters, use the oil permitted by the engine, 

Ambient temperature: -15°C < T < 40°C, system use 15W/40 CF-4, 

In the other temperature, system use the other type of diesel lubricating oil not lower than the level of CF grade of GB11122, CD, CG, and CH grade oil are not permitted, the engine has no oil inside when leave the factory 


◆ Electrical control system 

Starter, rated power is 2.3 kW, rated voltage is 12V, hermetic structure 

Denso adjuster, generator, 12V, 40A 

No gauge on the diesel, with oil pressure switch, without water temperature sensor, and the connector of the water temperature sensor is blocked by the bolt to prevent the oil or water leaks. 


Customer Installation and Reviews of BD Series Equip with DD Bus Air Conditioner


Here is a Guchen bus air conditioner project for Qatar old TATA buses. The clients ordered BD series bus ac units and equip with DD series independent ac units for their buses. Because of the local ambient temperature is very hot in summer, so equip with DD series are necessary. Our customers gave a highly commend on Guchen bus air conditioner system, especially mount on the independent ac, the cooling capacity is enough a lot for their local condition.

-----Guchen BD series Bus AC Equip with DD series independent ac Units for Qatar Old Tata Buses Project

Why Choose Guchen?

◆ GUCHEN is specialized in exporting Bus Air Conditioner for more than 20 years.
◆ GUCHEN has famous bus air conditioner parts suppliers, such as Bock, Bitzer and Valeo, which can offer customers’ a high quality products and assurance.
◆ 2 years after sales service
◆ 20, 0000 km journey guarantee
◆ Spare parts free change in 2 years
◆ 7*24h after sales online chatting
◆ Our experienced technicians and design engineers are capable of analyzing client’s needs and designing the most suitable plant configuration to satisfy the project specifications.

DD Series Bus Air Conditioner Technology Data


Engine Voltage

AC Voltage

Engine Displacement

Engine Power

Cooling Range


Vehicle Mached 


Yanmar or Isuzu

DC 24V




12-14 meter Shuttle Bus

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