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Heat Exchangers. For the foreseeable future, it is anticipated that heat exchangers will
be made of aluminum and will remain in the front of the truck behind a grille, but that lower
hood lines will force new shapes, concepts, and packaging styles. There will be more
calculation/simulation and less engine/vehicle testing, leading to greater use of computational
fluid dynamics (CFD) in design, for both component improvement and complete underhood
thermal management.
hood lines will force new shapes, concepts, and packaging styles. There will be more
calculation/simulation and less engine/vehicle testing, leading to greater use of computational
fluid dynamics (CFD) in design, for both component improvement and complete underhood
thermal management.
Fans and Fan Drives. Future key issues relative to fan drives are torque capacity (need
to handle a load in excess of 60 hp), variable-speed control, step-up ratios, and system
integration; also important are maintenance issues related to radiator and cab air conditioning,
charge-air cooling, and fouling. Alternate fan technologies must be considered in future designs
because fan geometry is essentially fixed by the available space, fan speed is at or near
maximum, and fan power cannot increase (because of fuel economy, fan-drive-system costs, and
fan noise).
integration; also important are maintenance issues related to radiator and cab air conditioning,
charge-air cooling, and fouling. Alternate fan technologies must be considered in future designs
because fan geometry is essentially fixed by the available space, fan speed is at or near
maximum, and fan power cannot increase (because of fuel economy, fan-drive-system costs, and
fan noise).
Coolant Pumps. Several trends related to diesel engines and truck design will increase
the thermal load on the cooling system of the vehicle. With respect to the engine, these trends
include later injection timing for NOx control, EGR, advanced turbochargers, exhaust-gas
include later injection timing for NOx control, EGR, advanced turbochargers, exhaust-gas
oxidation catalysts, longer maintenance intervals, and extended engine life. Vehicle trends
include increased power; integrated electronic control systems; reduced frontal area; increased
"hotel" loads; high-efficiency, lightweight components; liquid-cooled brakes; and liquid-cooled
alternators.
include increased power; integrated electronic control systems; reduced frontal area; increased
"hotel" loads; high-efficiency, lightweight components; liquid-cooled brakes; and liquid-cooled
alternators.
In current systems, coolant flow and pressure are directly related to engine speed and
thermostat setting. Also, cooling systems are sized for the maximum thermal load at high
ambient temperatures. As a result, performance under typical conditions is less than optimal.
There is a need for increased pump reliability/durability, higher efficiency, and variable-speed
(electric) drives.
ambient temperatures. As a result, performance under typical conditions is less than optimal.
There is a need for increased pump reliability/durability, higher efficiency, and variable-speed
(electric) drives.
The advantages of an advanced cooling system based on a variable-speed coolant pump
include constant and higher engine temperature, faster engine warm-up, smaller heat exchangers,
improved fuel economy, reduced cooling fan operation, and faster cab heating.
improved fuel economy, reduced cooling fan operation, and faster cab heating.
Cab Climate Control Systems. There is a need to improve driver comfort and
ergonomics. This will contribute to driver retention, which, in turn, will enhance safety. System
efficiencies must also be improved, focusing on, among other things, engine/chassis integration,
controls, noise reduction, and insulation. In addition to incremental component and system
improvements, quantum leaps also are required.
efficiencies must also be improved, focusing on, among other things, engine/chassis integration,
controls, noise reduction, and insulation. In addition to incremental component and system
improvements, quantum leaps also are required.
Transport Refrigeration. Demands for transport refrigeration can be expected to
increase. The industry also must address related environmental issues. Alternatives to the vapor-
compression refrigeration system should be evaluated, including Lorentz cycles, Stirling cycle,
compression refrigeration system should be evaluated, including Lorentz cycles, Stirling cycle,