Rising energy costs are spurring engineers to recover power lost in vehicle stops and starts. Instead of accelerating from a standstill—an inefficient use of internal combustion power when compared with highway cruising—engineers want to store energy generated during driving and braking, then rechannel it to get up to speed.

Most recovery technologies store energy in batteries or spinning flywheels. Now add to the list RunWise, a pressurized hydraulic system developed by Parker Hannifin Corp. It will make its debut on a new refuse (don't even think of using the word "garbage") truck, the model E3, to be introduced by Autocar LLC of Hagerston, Ind., in the fall of 2007.

An energy recovery unit aims to cut fuel use by up to half on refuse trucks like the Autocar E3.

"We're specifically targeting our efforts toward heavy trucks that generate high torques and have lots of starts and stops," said Clive Hindle, manager of Parker Hannifin's energy recovery business unit in Olive Branch, Miss. Refuse trucks certainly qualify. They average about 65,000 to 75,000 pounds and make as many as 1,200 stops per day.

RunWise powers the truck from stop to stop, repressurizing the hydraulic fluid every time the vehicle brakes. It is robust enough to reach cruising speed, where it hands off to the truck's internal combustion engine. This was enough to slash fuel consumption by 40 to 50 percent in side-by-side tests with a conventional refuse truck, Hindle said. "We'll probably do even better in the future," he added.

The system's power drive includes a gearbox, primary pump, and two secondary pumps that also act as motors. Running the engine drives the primary, which pumps hydraulic fluid into two carbon fiber-reinforced composite accumulator tanks that store it at more than 5,000 psi. When it comes time to start a stationary truck, the hydraulic fluid flows from the accumulators to two hydrostatic motors that drive the vehicle forward. At 40 miles per hour, the truck's electronic controller hands off power to the internal combustion engine.

The RunWise recovery unit stores energy as pressurized hydraulic fluid in carbon-reinforced tanks.

The truck also recharges the accumulators when it brakes. The two hydrostatic motors act as secondary pumps and refill the accumulators, converting forward motion into pressure. The truck's friction brakes do not even come on line until the pedal is depressed halfway, said Hindle. The system reduces brake wear, which Hindle called "a significant value proposition to our customers."

RunWise delivers several other advantages. It boosts acceleration up to 25 percent, enabling trucks to whisk quickly between stops along a route. The electronic controller eliminates shifting gears on stop-and-go routes. The truck runs more quietly and produces fewer emissions. Equally important, said Hindle, the trucking industry understands hydraulics and feels quite comfortable with the technology. "We see nothing but upside," he said.

Hindle said the unit is pricy, but added that Parker Hannifin is targeting a payback period of two to three years. Since refuse trucks usually last 10 to 12 years, operators should recoup their investment several times over. He is also looking for ways to apply the technology to buses and delivery trucks.

Electric motors making the jump to hybrid and fuel cell vehicles will become more valuable as they grow smaller and more efficient. A new type of capacitor designed to fit over the motor shaft promises to simplify motor designs.

The electronics associated with motors have long been a problem to designers concerned with size. Batteries and fuel cells supply current steadily, but three-phase motors need power in rapid pulses. That means adding a capacitor to store the steady flow of electrical energy and release it in quick bursts, and an inverter to convert those bursts into alternating current.

Those electronics are usually mounted outside the motor. That poses problems where space is limited. To slim down, designs sometimes mount inverters and capacitors on the motor shaft. This choice produces a smaller profile, but leads to several capacitor tradeoffs, according to Terry Hosking, vice president of engineering at the Power Ring division of SBE Inc. in Barre, Vt.

Shaft-mounted capacitors consist of wound capacitor coils wired to one another and seated in an annular disc. The free space left by this circles-within-a-circle design is about one-quarter to one-third of the total that could be used to boost capacitance and drive higher-powered motors.

Heat generated by current also poses a problem to the most common capacitor winding material, metalized polypropylene film. The polymer begins to melt above 105°C, and that property limits operating temperatures.

The solution, Hosking said, involves a new ring capacitor that eliminates discrete capacitor coils. SBE winds the entire annular structure as a single piece. This fully utilizes all the area on the ring, allowing high capacitance.

If this sounds like an obvious solution, Hosking agrees. "The problem," he said, "was that there was no commercial winding equipment to make it, so we had to develop our own."

The new design has a second benefit to go with higher charge densities. Tests and simulations show that it generates far more capacitance for the same temperature rise as a conventional coil and disc system or equal capacitance at significantly cooler temperatures.

This opens the door to more space-saving designs. Automakers apparently agree. According to SBE, it has delivered its first power ring capacitors to General Motors Corp. for a new fuel cell prototype.

This year, North American original equipment manufacturers and system integrators will harness 1.5 million low-horsepower

drives for components and machinery. Companies that make multiple product lines or customized equipment face a challenge when it comes to programming and reprogramming drives to match them with a specific application (which may evolve over time and require further programming).

ABB's hand-held FlashDrop enables users to program drives without even unpacking them.

ABB Inc. says it may have a way to simplify the process and speed programming throughput. Its new FlashDrop technology enables OEMs to program a drive in seconds—without powering it up or even unpacking it.

"This is advantageous when OEMs pick drives from their stock as their equipment is being assembled and download the appropriate parameter set before power is applied to the machine," said Mark Kenyon, ABB's product marketing manager for low-voltage drives. "The parameter set has previously been proven, and questions of machine misoperation or malfunction due to drive-related issues can be avoided, reducing troubleshooting time.

"Adjustment to parameters without power being applied can be critical to an OEM since it wouldn't require a skilled electrician to perform the process," Kenyon said.

FlashDrop itself is a hand-held tool that plugs into the drive face. It can hold up to 20 complete parameter sets. "You can use these for 20 different drives, or one drive and 20 batch programs, or any combination," Kenyon said.

Users can name each parameter set for an associated application. It enables OEMs to simplify menus and keeps operators from resetting critical parameters. Users can also use their PCs to edit and store menus and parameters for downloading to the FlashDrop unit.

ABB has released two new low-voltage ac drives with optional FlashDrop capabilities. The ACS150 has a 0.5- to 5-hp rating and operates in variable frequency mode. The ACS350 handles 0.5- to 10-hp motors and operates in variable frequency, sensorless vector, or closed loop vector mode. It also features built-in logic for sequencing motor and machinery operation.

Measuring the rotary torque in driveshafts and rotating machinery has never proved simple or cheap, but a technology widely used as a radio frequency filter on mobile phones may change that.

Developed by Sensor Technology Ltd. of Upper Heyford, U.K., the new transducer is based on surface acoustic waves, which travel along the surface of materials. Sensor Technology creates the waves by running a current through the interlaced electrodes of two micrometer-scale combs on top of a quartz substrate. Because quartz is piezoelectric, it oscillates when excited by the current.

The two sensors on this shaft use surface acoustic waves to measure torque and transmit the information wirelessly to a recorder.

The company's design consists of two sensors glued along the circumference of a shaft in a "V" configuration. "Subject the shaft to strain, and one sensor will extend and the other will compress," said sales engineer Mark Ingham. "This alters the distance between the fingers of the comb, which changes the frequency of the quartz. The frequency of one sensor will go up, the other will go down. Measuring the difference between the two provides the torque and speed of the shaft."

The measurement shaft runs through a small unit that communicates with the sensors via radio frequency. The noncontacting system can measure torque between 100 millinewton-meters up to more than 10,000 newton-meters. The device is highly immune to magnetic fields and will work in motors that overwhelm other technologies with random electronic interference.

The new noncontact torque transducers have been used in applications as diverse as testing custom slip ring motors, determining when servo motors need repairs, and recording the resistance of lava flowing down a volcano. Other potential uses range from condition monitoring of tooling to motor, machinery, and variable speed drive control.

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