Energy losses in automotive coolant circuits stem from three main sources: aerodynamic drag, fan power and coolant pump power. A study of a production coolant circuit has shown that much of the pump power is wasted. This is because the engine driven pump is not well matched to the cooling requirements and energy is frequently dissipated through a partially closed thermostat. In addition, the pump itself is of crude design and low efficiency. Experience with development engines has shown that adequate cooling may be achieved with 'precision cooled' designs utilising small bore tappings in critical areas of high heat flux. In parallel, prototype electric cooling pumps have been developed having hydraulic efficiencies some three times greater than production units. The effectiveness of this approach has been demonstrated by application to a concept vehicle. Microprocessor control of the pump has enabled adequate cooling with a pump which has a maximum power only 20 % of that absorbed by the production unit. For many road conditions the pump runs at only half speed, reducing power by about a further order of magnitude. Independent microprocessor control of pump speed opens the way for further developments, including improved part load performance and a programmed response to thermal transients.
Energy savings in hydraulic coolant circuits
Energieeinsparung in hydraulischen Kuehlsystemen
1989
7 Seiten, 9 Bilder, 6 Quellen
Conference paper
English
Energy savings in hydraulic coolant circuits
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