FOR IMMEDIATE RELEASE

The Whisper® is starting to demonstrate its full potential.

After promising first phase - current results turn out much better than expected.

Today's Date -- 

Operational testing of the reconfigured Whisper® is well underway and the fuel consumption continues to amaze. Measured over the total test distance covered to date; on average:

a mere 600 Watt-hours is being used to propel the Whisper® one kilometer in inner city operation.

This is the equivalent of 2.16 megajoules per kilometer. In 100 kilometers the Whisper® would thus use 60 kWh. Our current Auxiliary Power Unit (APU) would require 15 liters of diesel oil to supply the electric energy used during those 100 kilometers. This is 15.7 MPG or 6.7 kilometer per liter. The results are roughly equivalent to those measured by TNO in October of 2004 on the e-Traction® Bus, which also happens to be 1.5 tons lighter. The apparent improved efficiency is no doubt the result of the Lithium-Ion batteries, that have been installed since that time, and the improved energy management systems of the APU.

Equally remarkable has been the surprisingly low energy consumption at higher speeds. The wind-resistance penalty had been expected to adversely impact the required energy to sustain the speed than now appears to be the case. At a sustained speed of 80 kilometers per hour the Whisper® uses only 512 Watts, or 1.84 megajoules, per kilometer. This is 51.2 kWh after 100 kilometers. It would take 12.8 liter of diesel oil with the current APU to supply this amount of electric energy. Thus the fuel mileage at 80 km/h is: 18.4 MPG or 7.8 kilometer per liter. 

The environmental impact of this low energy consumption is commensurate, because a conventional diesel powered city bus uses at least three times the amount of fuel and thus its emissions are minimally 200% higher than those of the Whisper®. Furthermore the Whisper® now features the e-Mission™ Particle Eliminator on its roof which together with the lower fuel consumption can reduce particle emissions by as much as 93%.

History:

The town of Apeldoorn, in the Netherlands, with financial support from the province of Gelderland, its regional transit provider Connexxion, the coachbuilder VDL Berkhof, the energy company Nuon, and e-Traction® jointly agreed, on April 12^th 2003, to convert of a brand new, highly fuel efficient Ambassador 200 bus with a series hybrid, direct drive, electric, wheel hub traction system with TheWheel™ SM700/3AL.  The original Whisper® was first introduced to the press in October 2003, barely four months after the start of conversion in June 2003, and started road testing early 2004.

It was clear from the outset that the noise level of the Whisper® would be substantially below the average 78 decibels experienced with conventional diesel buses and was measured as low as 58 decibels. The air pollution was was lower too, although there remained additional room for improvement. The fuel savings, compared to the ultra efficient Ambassador 200 diesel bus of VDL Berkhof, however, proved to be disappointing. In a simulated city operation comparison test the hybrid version of the Ambassador bus demonstrated only a 7.4% improvement in fuel mileage in May of 2004.

In depth analysis attributed the disappointing fuel savings of the Whisper® 1 in large part to the high rolling resistance of the low pressure tractor tires that were specially created for this application by the Continental Tire Company with road worthy thread. Whereas a conventional Ambassador bus has a rolling resistance of 13 kilograms per ton, the Whisper® had one of 19 kg/ton. The rolling resistance of the recently completed e-Traction® Bus incidentally is a mere 8 kg/ton. Due to the disappointing performance of the batteries the generator wound up doing extra duty and thus negatively impacting fuel consumption. As it turned out the oversized traction system was never taxed for more than 15% and normally operated at only at 8% of its potential. This meant resulted in unnecessary weight and resistance of the oversized units. In addition, these oversized units, and particularly their tires, also resulted in  a loss of 8 seats in the bus.

Complicating the decision to commence the planned second development phase were a lack of funding and the loss of project partner Connexxion of the concession in Apeldoorn and surroundings. To resolve this problem e-Traction® has offered to assume ownership of The Whisper®, and thus become solely responsibility for the conversion from the Whisper® 1 configuration to that of the Whisper® with its own financial and human resources.

A lot was learned from the initial tests and the knowledge gained was put to good use in the conversion to the Whisper®. The newly developed TheWheel™ SM500/2FE traction units were on a newly e-Traction® developed universal rear axle. The Nickel-Zinc batteries were be replaced by much lighter and stable Lithium-Ion units. The generator was equipped with an e-Traction® SM350/1AL unit, which allows it to produce direct current instead of alternating current. This significant change will also make it possible to vary the generator speed to the precise demand of the system, further optimizing fuel consumption. The 8 seats lost in the early version will be regained with the use of much smaller diameter super-single Michelin X One XDU, 455/45R22.5 tire.

Meanwhile, the mechanical work was completed by February 2005, whereupon the Whisper® returned to VDL Berkhof for reconstruction to the original coachwork configuration. Road testing commenced late March 2005 in the town of Apeldoorn for operational testing and verification of the key performance parameters. The regularly updated progress report provides insights to the results achieved to date. Assuming these findings prove satisfactory, a decision to proceed to purchase and/or conversion of buses operated in Apeldoorn and surroundings should reasonably be expected.

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Last modified: April 28, 2009