ELECTRIC WATER PUMP BULLETIN

DAVIES, CRAIG PTY. LTD.

ACN NO 004 918 825

LICENSED TO MANUFACTURE UNDER A QUALITY SYSTEM COMPLYING WITH

ISO 9002

WEB SITE www.daviescraig.com.au

The automotive industry has taken its first great leap forward in engine cooling technology in 30 years with the release of the Davies, Craig universal fitting electric water pump for cars, trucks, buses and boats.

Davies, Craig’s Managing Director, Mr. Richard Davies, said the pump, the Davies, Craig EWP, has been designed to replace the mechanically driven pump to increase the power available to the drive wheels of the vehicle, and improve cooling.

The pump was developed over the last two years in a $1.2M research and development project undertaken by Davies, Craig, the Melbourne based Australian auto component manufacturer which was the first to introduce electric radiator fans to Australia and the USA nearly 30 years ago,

At that time, almost all car engines had a belt driven radiator fan, which was a slave to the engine speed; every time the engine went round the fan went round too, even if the engine was cold, or the car was travelling fast enough for the ram air to cool the engine.

Also when the engine speed was high during acceleration and passing through the gears, the mechanical fan speed was also high and taking more and more power from the drive wheels as the fan’s speed increased. When Davies, Craig launched its range of electric Thermatic radiator fans, the benefits to the motorist were fuel savings, better temperature control and improved vehicle performance. Now, most cars have an electric fan as standard equipment.

In the same way until now, all car engines have had a belt driven mechanical water pump, which circulates coolant around the engine and through the radiator. They have the same disadvantages as the mechanical fans as they too are slaves to the engine speed and run when not required. They also reach very high speeds when the engine is accelerating through the gears and reduce the power available to the drive wheels.

Usually the most difficult condition to cool a car engine is when it is stationary and idling in high ambient temperatures. In this situation, the mechanical pump produces its minimum flow rate of about 20 litres per minute. At the highest engine speed the rate is typically increased to about 180 litres per minute, but because the coolant is flowing so fast, it spends less time in the radiator and very little extra heat is removed than when the flow rate is about 80 litres per minute. The power taken by the belt driven pump increases more and more at high flow rates because the resistance to flow offered in the radiator also increases.

The Davies, Craig electric pump operates at its maximum efficiency design rate of 80 litres/ minute when the full 12 volts is applied to its motor. But in most situations that rate is more then necessary so Davies, Craig has developed an electronic intelligent controller. It senses the temperature in the engine and then varies the voltage to the pump motor between 4 and 12 volts thus varying the pump speed so that the engine temperature is precisely controlled to a set temperature. Current consumption for 90% of motoring time will be about two amps and up to six amps when the pump is full on. Davies, Craig has taken out patents and design registrations on the product.

The Davies, Craig electric pump will be sold as a conversion kit at around $280, and the smart controller option will cost $270. Both will carry a two-year warranty.

The installation involves removing the mechanical pump, pulling off the impeller from the pump shaft, and re-installing the mechanical pump housing and its belt. The pump is now an idler pulley doing no work and causing no drain on the power to the wheels. Alternatively the water pump pulley can be deleted from the belt system using a shorter belt.

A section of four inches of the lower radiator hose is cut out and the electric water pump inserted. The engine thermostat is then removed, (as the pump acts as a thermostat), and the electric pump wired up.

In some situations such as stationary engines or in cases of chronic overheating found in some four-wheel drive vehicles, the pump can be wired to run continuously, have a manual switch, or an automatic thermal on-off switch. The best control is with the electronic intelligent controller.

Drivers will notice an improvement in acceleration and performance especially in the top rev range, a better control of engine temperature, along with an increase in cooling capacity and fuel saving, especially during high speed cruising and in the city. A five-litre V8 engine could produce an extra 8% to 10 % power at the drive wheels. Maximum engine speed is increased and automatic gear changes are sweeter.

But the biggest boon will be to engine life because the electric pump can be programmed to run on after a hot engine shut down for about a minute, which is usually enough time to wash out built up heat from the engine block.

Owners of vintage cars, which tend to overheat on hot days, are set to benefit greatly from the EWP. They will be able to add the pump to the existing system to supplement cooling and protect precious vintage engines.

The biggest demand for the pump is expected to come from performance, off road, and vintage vehicles and vehicles with overheating problems.

Because the concept of electric water pumps is entirely new and in order to maintain its quality reputation, Davies, Craig has over-engineered and proved the pump exhaustively so that it will withstand all possible operating conditions including coolant additives. "We cannot afford to have one pump fail in the ‘heat of battle’ " said Mr. Davies.

The EWP is about the size of two saucers put together, weighs 800 grams, uses a maximum of six amps and is made from the same type of engineering plastic used for the side tanks of modern radiators. It can withstand temperatures of minus 26 to 140 degrees C (280 degrees F) and a pressure of 50 psi.

The pump motor has sufficient torque for the impeller to move the sludge found in some old radiators. The unit will withstand heavy salt road spray, but total immersion such as in a river crossing should be kept to a minimum unless the motor is sealed.

"The way technology is exploding in the auto industry these days; it may be only 10 years before most cars have electric water pumps".

For further information:

Davies, Craig Tel 61 3 9646 3051

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