Friday, January 26, 2001

Escanaba, MI--An entirely new class of water pump from Engineered Machined Products Inc. improves flow control, reduces warrantee costs, and boosts efficiency compared to conventional pulley-driven engine-cooling pumps. The secret: an integral liquid-cooled electric drive motor and a proprietary mixed-flow impeller and diffuser design.

Using either a switched reluctance or brushless permanent magnet motor, the E.M.P. Advanced Electric Pump generates coolant flow rate based on engine temperature rather than engine speed. "We don't have the only electric water pump in the world," explains E.M.P. VP of Product Development David Allen. "But our integral motor design allows higher efficiencies because we can liquid cool it instead of using a fan."

Moreover, elimination of side loads induced by belts or gears effectively doubles bearing life and creates a favorable environment for seals because they are no longer subject to shaft deflections associated with drive mechanism loading. In fact, the motor-driven pump uses smaller, less-expensive bearings than traditional pumps and requires no external mechanical seals.

Since the location of the drive mechanism determines placement of a conventional pump on the engine, it typically requires more time and labor to replace, according to E.M.P. President Brian Larche. "It also means large parts inventories with literally hundreds of conventional water pump designs." In contrast, the E.M.P. pump's in-line design eliminates the need for custom-built pumps, and will decrease pump inventory for both military and commercial applications because it can mount anywhere in the engine compartment.

But fluid-pumping efficiency is the real key to success in any application. Most water pumps use a volute, or spiral-scroll-shaped form machined at the edge of the impeller to decrease turbulence in fluid exiting the pump, Allen explains. "However, fluid coming off the impeller bombards fluid in the volute and actually decreases efficiency."

Instead, the new E.M.P. pump uses a diffuser that immediately redirects fluid as it comes off the impeller into a stationary set of vanes, isolating it from impeller interference. "This boosts efficiency because the diffuser collects fluid from the impeller for a full 360 degrees as compared to approximately 90 degrees of a volute style pump," says Allen.

At half the size of conventional over-the-road engine cooling pumps, the patented, fully controllable E.M.P. Pump increases efficiency 30% and reduces weight 60%. The pump and controls thermally optimize the engine for a 3 to 7% increase in fuel economy. It also reduces emissions and cools the engine components after shutdown to decrease thermal fatigue. For more information visit www.emp-corp.com/html/news/car_craft.shtml.