Summary of Volvo Cooling System Design

Summary of System Design

The following points must be given extra thorough consideration when designing a cooling system:

• The maximum ambient temperature the engine must operate in.

• Cooling air flow direction, i.e. if a puller or pusher fan is to be used. A pusher fan is recommended for generator sets to avoid generator overheating. On mobile applications, consideration must be give to any slipstream.

• Engine heat radiation causes a rise in cooling air temperature in pusher fan systems.

• Generator heat contribution is 7-10 % of net engine power.

• Additional coolers in front of the radiator (puller fan) or behind the radiator (pusher fan) will

cause a rise in cooling air temperature and a reduction in airflow.

• The radiator may become clogged in dusty environments, which will impair cooling capacity.

The radiator must be installed so that it can easily be cleaned. Grilles / filters are available

as options.

• There must be as few obstacles to cooling air flow as possible. The design of air ducts, grille

and engine compartment is important.

• Hot air recirculation will impair cooling capacity significantly and must be prevented by sealing.

• Where accessory components such as a torque converter oil cooler are connected to the coolant system, it is necessary to know the cooling requirement for such components.

• Consideration must be given to the altitude above sea level at the location where the engine

will be used, as ATB is reduced by around 1.4 °C (34.5 °F) at 300 m (984 ft.)

• If it is necessary to increase cooling capacity, it must be done in the first instance by using a

larger radiator and improving cooling air flow.

Important to bear in mind regarding the coolant circuit

• Coolant flow and external circuit sensitivity to pressure drop. One extremely critical parameter when designing a cooling system is coolant flow. The pressure in the coolant system, which the pump works against, is linear to the amount of coolant that must circulate. When the thermostat opens back pressure increases and flow drops. Therefore, do not increase the external coolant system beyond the permissible maximum volumes specified in the technical data for each individual engine.

Also refer to technical data/cooling system

• Cooling effect and maximum cooling temperature. Refer to technical data/cooling system

“heat rejection from engine” and “Maximum top tank temperature”

• Static main pressure. Refer to technical data/cooling system

“maximum static main pressure” and “minimum static main pressure”

• Expansion tank volume. The total amount of coolant used in the system affects the appropriate size of the expansion tank. Minimum expansion tank size is 18 % of the total coolant volume.

Refer to the expansion tank chapter

• Venting.

Refer to the venting, nipples, pipes and hoses chapter

• Pipe and hose quality Refer to the radiator, pipes and hoses chapter.

Important to bear in mind regarding the charge air circuit

• Charge air temperature and cooling capacity. Engine charge air temperature should be as low

as possible. This is beneficial for fuel consumption and increases total engine service life. (lower stress effects from heat at maximum load points). Therefore pay attention to the need for effective cooling.

• Pressure drop across the charge air system. Refer to technical data/cooling system/charge

air system

• Load take-up. Be aware that the increase in air volume created by extending the charge air pipes will have a drastically negative effect on load take-up.

• Pipe runs and installation (clamps). Refer to the charge air cooler chapter

Induction System

General

The air inlet system is one of the most important parts of the engine installation as it is able to directly affect engine power, fuel consumption, exhaust emissions and engine service life. Bearing this in mind the air inlet system must be designed so that it is able to provide the engine with clean, dry, cold air with the smallest possible flow limitation. The system must also be designed to cope with the shock loads and operating conditions that occur during use. It must also provide reliable sealing and durability.

Air Inlet System

The air inlet system consists of three main components:

- Air inlet - before filter

- Air cleaner