Cooling for commercial vehicles

Strict emission standards and the search for measures to reduce consumption are the main factors driving development in the truck sector today. Consequently, it is becoming increasingly important to adopt an integrated approach to analyzing and optimizing cooling functions (thermal management).

Engine cooling components, modules, and systems

Charge air coolers

Indirect charge air cooling systems use extremely compact coolers that are cooled by the coolant of the separate low-temperature cooling circuit. Since the low-temperature radiator has a large front surface and is swept by the cold cooling air flow, very low charge air temperatures can be achieved. Due to their superior efficiency (as compared to a charge air/air cooler), they can be designed with very compact dimensions and mounted onto the engine. In transient driving conditions, they provide for a much more stable intake air temperature and thus help reduce fuel consumption.

Cooling modules

They comprise multiple engine cooling components as well as the condenser, which forms part of the air conditioning circuit. The cooling module primarily consists of a radiator and the charge air cooler. In indirect (coolant-cooled) charge air cooling systems, the charge air cooler is replaced by a low-temperature radiator which is located between the condenser and the radiator. For maximum efficiency, all components are optimally matched. The modules are assembled according to the vehicle design concept, thus reducing development, production, and logistics costs.

Low temperature radiators

In an indirect charge air cooling system, rather than being released directly to the ambient air, the heat from the charge air cooler first passes through a separate, low-temperature coolant circuit (LT cooling circuit) before being discharged to the ambient air by a downstream, low-temperature radiator (LT radiator).The LT radiator of the indirect charge air cooling system is mounted onto the engine cooling module and can be designed more compactly than the direct charge air cooler, without sacrificing performance. This is because heat is transferred from the air to the coolant. The LT radiator can also be optionally used to ensure optimum thermal management of a temperature-sensitive lithium-ion battery, its power electronics, and soon also the condenser of the refrigerant circuit.

Oil heating and cooling systems

Current MAHLE heating and cooling modules are able to also handle channel guidance, temperature regulation, and filtering of the coolant flow. An optimized channel guidance and distribution of the coolant flow provides coolant to the heat exchangers of the engine and transmission as well as for fuel as needed.


The most important component of the cooling module is the radiator, which consists of the radiator core and plastic tanks with all requisite connections and fastening elements. The radiator core is usually made of aluminum, while the coolant tanks are made either of aluminum—just like the core—or fiber glass-reinforced polyamide.

Thermostats and control valves

The wide variety of engine cooling tasks can be achieved only by intelligently controlling the energy flows that arise. Various systems and engine components must be supplied with coolant as required. In modern systems, this takes place with different temperature levels and separate cooling circuits. Intelligent control systems from MAHLE, such as engine operating map thermostats, ensure demand-actuated and precise temperature regulation and thus promote more efficient operation, reduced consumption, less wear, and lower emissions.

Visco® fan drive

Visco® fans and Visco® fan drives

Electronically controlled Visco® fans are used in a wide range of vehicles—from heavy trucks to vans and SUVs with powerful engines. They detect all relevant temperature values for cooling and air conditioning purposes and set the exact required fan speed. This ability to deliver precision, on-demand control while ensuring rapid response times and low idling speeds when the drive is deactivated have a positive influence on fuel economy, driving comfort, and noise emissions.

With the Visco® hybrid fan drive, MAHLE offers a solution tailored specifically to hybrid drives. The MAHLE technology combines the advantages of the Visco® drive with those of electric actuation, including demand-based fan performance control, increased efficiency, and energy recuperation.

Exhaust gas recirculation (EGR)

One approach to meeting the NOx (nitrogen oxide) emissions limits is to incorporate cooled exhaust gas recirculation (EGR). This involves extracting a portion of the main exhaust flow between the engine outlet and the turbine, cooling it in a special heat exchanger, and feeding it back to the intake air downstream of the charge air cooler. The combustion temperature in the engine is thereby lowered, thus reducing the formation of NOx. Our EGR coolers offer exceptional thermomechanical strength, reduced tendency to sooting, and outstanding specific performance. Thanks to the use of high-performance winglet tubes, extremely stable EGR temperatures—and thus improved EGR control—can be achieved.

Motors for electric pumps

Pumps for water (or other liquids) are driven by electric motors. These can be used in wet or dry rotor environments. More controlled flow of coolant, reduction of fuel consumption and pollution (CO2), longer pump life, and quieter operation are some of the advantages found in new, modern, hybrid and electric passenger cars with electrically driven water pumps. Highly innovative rotor protection for operation in liquid is used in the motor design to ensure reliable, long-life operation.