A cool new con­cept

Motor Equipment News - - KEEPING IT COOL -

Elec­tric wa­ter pumps for au­to­mo­tive use have been avail­able for some years, but for mainly they’ve been used for rac­ing ap­pli­ca­tions. Self-con­tained elec­tric wa­ter pumps are of­ten used in drag rac­ing be­tween runs. The aim is to re­duce the en­gine’s tem­per­a­ture and the par­a­sitic power loss of a me­chan­i­cal wa­ter pump.

Early at­tempts to use race-style elec­tric wa­ter pumps on the street weren’t very sat­is­fac­tory, but all that has changed, and in fact one Euro­pean man­u­fac­turer be­gan us­ing elec­tric wa­ter pumps around 2007, and sev­eral oth­ers are fol­low­ing suit. Now there are af­ter­mar­ket ver­sions that are suit­able for reg­u­lar daily drive use.

Over the past 45 years the Davies Craig en­gine cool­ing prod­uct line has grown, and now in­cludes its rev­o­lu­tion­ary elec­tric wa­ter pump, or EWP, man­u­fac­tured and sold in Aus­tralia, and now ex­ported to NZ, US, Europe, and Ja­pan.

An EWP has many ad­van­tages over the en­gine-driven va­ri­ety. It will in­crease power and torque by dis­abling the me­chan­i­cal pump, which uses en­gine power to drive it. Ad­di­tional ben­e­fits are im­proved cool­ing ca­pac­ity and fuel econ­omy, and the elim­i­na­tion of en­gine heat soak af­ter a hot en­gine shut down. En­gine cool­ing is im­proved thanks to a higher flow rate at idle and low en­gine speeds, when there is lit­tle or no ram air, and when the en­gine is switched off.

Here’s what Davies Craig’s sales and mar­ket­ing man­ager, John Ben­son has to say:

What do you con­sider nor­mal op­er­at­ing en­gine op­er­at­ing tem­per­a­ture?

This is de­pen­dent on the type, size, ca­pac­ity, work­load and en­vi­ron­ment, but the best en­gine tem­per­a­ture is usu­ally be­tween 185 deg.F - 221 deg.F. The man­u­fac­turer rec­om­mends op­ti­mum op­er­at­ing tem­per­a­ture via the me­chan­i­cal ther­mo­stat in the en­gine, and this is the ex­act tem­per­a­ture set­ting rec­om­mended when the Davies Craig LCD EWP/fan dig­i­tal con­troller is in­stalled.

How does the pump ac­com­mo­date vary­ing en­gine speeds?

The EWP op­er­ates in­de­pen­dently of the en­gine’s speed, a ma­jor ben­e­fit over me­chan­i­cally driven pumps which only cir­cu­late coolant while the mo­tor is run­ning. When used with the con­troller, the pump speed is in­creased and de­creased based on the en­gine’s op­er­at­ing tem­per­a­ture, in­stead of rpm. This means the en­gine’s tem­per­a­ture will de­ter­mine the pump’s cir­cu­la­tion ca­pac­ity of the en­gine coolant.

Once the en­gine tem­per­a­ture be­gins to climb, the pump’s speed in­creases ac­cord­ingly. When the en­gine’s tem­per­a­ture reaches 5 deg.C be­low the pre-se­lected tar­geted/set op­er­at­ing tem­per­a­ture, the EWP will in­crease the flow rate, reach­ing 100 per­cent. When the en­gine tem­per­a­ture rises +3 deg.C above the set/tar­geted

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