New trends in fan drive technology offer distinct advantage for city buses and other mobile applications. The sharp reduction in emission values for heavy duty engines used in commercial vehicles and strict regulations result in a complex scenario for engine and vehicle manufacturers regarding the engine and exhaust gas treatment devices.
Many manufacturers have chosen the path of exhaust gas recirculation or similar processes, combined with shifting of peak torque to the lower speed range. Engines optimized in this way may need complex cooling management system to enable operating temperature to be maintained in a narrow band.
Trucks and buses with front-mounted engines are able to make use of relative air speed for cooling. In modern urban buses, whose engines are rear-mounted and which do not reach high speed and mostly in stop-and-go cycles, the cooling requirements are more demanding.
Bosch Rexroth’s intelligent hydrostatic fan drive system provides necessary cooling as demanded by the engine to achieve lower emission levels, no matter what the air stream and engine speed is.
Bosch Rexroth’s system solution for hydrostatic fan drive includes axial piston pumps and external gear motors. CAN-bus-compatible control electronics optimized for fan drives perfectly meet the requirement profile of intelligent regulation and cooling output. These variable systems with closed loop electronic circuit can be programmed exactly to supply the required cooling output at all times, regardless of the speed of the engine.
The electronically controlled A10VO ED variable pump supplies the required flow to an external gear motor that drives the fan. According to company estimates, the variable pump system reduces fuel consumption upto a maximum of five per cent compared with the conventional belt drives. However, the estimation of fuel savings depends on individual applications.
The variable fan drive is managed by a BODAS-RC electronic controller from Bosch Rexroth that features a tailored software solution for mobile applications. Automatic Fan Control (AFC) software for fan drive evaluates upto eight input signals, weighs them according to the maps in the control unit and generates a control signal for the variable pump.
Besides temperature, the user can also program other parameters to optimize operation. For example, the system recognizes when the driver activates the retarder for braking, and it knows when this happens more cooling output is needed for the combustion engine. This allows the controller to respond proactively to maintain the emission levels.
This system also provides several other advantages to manufacturers, as this solution separates the combustion engine and the coolers, allowing more installation layout choices.
Other development trends are combined systems. BODAS controllers are able to communicate with other systems in the vehicle via the CAN bus and can thus take on other tasks. With combined systems, the axial piston pump supplies additional auxiliary drives such as A/C compressors. One of the main gains is reduction of fuel consumption and hence operating costs.
Bosch Rexroth offers its customers the expertise of its application centres where the drive and control specialists tap the company’s knowledge and experience to configure the best solution. The hydrostatic fan drive shows how much potential this drive technology has in the field of electro hydraulics.
Bosch Rexroth of the Bosch Group achieved sales of approximately 5.8 billion Euros in 2008 with over 35,309 employees worldwide. Under the brand name of Rexroth, the company offers all drive and control technologies, from mechanics to hydraulics and pneumatics to electronics.
Many manufacturers have chosen the path of exhaust gas recirculation or similar processes, combined with shifting of peak torque to the lower speed range. Engines optimized in this way may need complex cooling management system to enable operating temperature to be maintained in a narrow band.
Trucks and buses with front-mounted engines are able to make use of relative air speed for cooling. In modern urban buses, whose engines are rear-mounted and which do not reach high speed and mostly in stop-and-go cycles, the cooling requirements are more demanding.
Bosch Rexroth’s intelligent hydrostatic fan drive system provides necessary cooling as demanded by the engine to achieve lower emission levels, no matter what the air stream and engine speed is.
Bosch Rexroth’s system solution for hydrostatic fan drive includes axial piston pumps and external gear motors. CAN-bus-compatible control electronics optimized for fan drives perfectly meet the requirement profile of intelligent regulation and cooling output. These variable systems with closed loop electronic circuit can be programmed exactly to supply the required cooling output at all times, regardless of the speed of the engine.
The electronically controlled A10VO ED variable pump supplies the required flow to an external gear motor that drives the fan. According to company estimates, the variable pump system reduces fuel consumption upto a maximum of five per cent compared with the conventional belt drives. However, the estimation of fuel savings depends on individual applications.
The variable fan drive is managed by a BODAS-RC electronic controller from Bosch Rexroth that features a tailored software solution for mobile applications. Automatic Fan Control (AFC) software for fan drive evaluates upto eight input signals, weighs them according to the maps in the control unit and generates a control signal for the variable pump.Besides temperature, the user can also program other parameters to optimize operation. For example, the system recognizes when the driver activates the retarder for braking, and it knows when this happens more cooling output is needed for the combustion engine. This allows the controller to respond proactively to maintain the emission levels.
This system also provides several other advantages to manufacturers, as this solution separates the combustion engine and the coolers, allowing more installation layout choices.
Other development trends are combined systems. BODAS controllers are able to communicate with other systems in the vehicle via the CAN bus and can thus take on other tasks. With combined systems, the axial piston pump supplies additional auxiliary drives such as A/C compressors. One of the main gains is reduction of fuel consumption and hence operating costs.
Bosch Rexroth offers its customers the expertise of its application centres where the drive and control specialists tap the company’s knowledge and experience to configure the best solution. The hydrostatic fan drive shows how much potential this drive technology has in the field of electro hydraulics.
Bosch Rexroth of the Bosch Group achieved sales of approximately 5.8 billion Euros in 2008 with over 35,309 employees worldwide. Under the brand name of Rexroth, the company offers all drive and control technologies, from mechanics to hydraulics and pneumatics to electronics.
Over five lakh customers worldwide utilize Rexroth’s unique technology knowledge to implement their innovative and future-oriented systems and machine designs.
