Trials are underway of a new type of hydraulic transmission for diesel powered rail vehicles that could be applied to non-electrified rail routes.
Chiltern Railways is helping to test the powertrain demonstrator as part of a wider powertrain competition funded by RSSB and Artemis Intelligent Power.
Project partner JCB will supply a diesel engine to power Artemis’s E-dyn 96 Digital Displacement hydraulic pump. The pump will supply flow to axle-mounted Digital Displacement motors and the transmission will be installed in a Chiltern Trains Driving Van Trailer.
The Digital Displacement Hybrid Rail Transmission project aims to reduce fuel consumption and improve engine performance by combining hydrostatic transmission with on board energy storage in the form of hydraulic accumulators, which store energy during braking for reuse during acceleration.
Stored energy can be reused to supplement engine power, reducing journey times through faster acceleration allowing trains to leave stations without producing emissions.
In use, the technology could be applied to non-electrified rail routes where electrification is difficult to justify on an economic basis.
According to RSSB, it also has the potential to provide benefits to the customer experience and to train planners in terms of reducing station dwell and journey times. The hybrid drive train can also be combined with a downsized engine to reduce the emissions and fuel consumption of the fleet.
Artemis Intelligent Power is testing the new solution on one of Chiltern Railways’ Mark 3 DVT vehicles. The test will take place for three months, starting in December 2017.
Interesting. But isn’t hydraulic fluid non-compressible? Would that involve some pneumatic element?
What’s the advantage compared with a flywheel?
BTW, non-availability of a regular and reliable rail service contributes to needs for private cars. Perhaps something to think about for councils interested in reduction of congestion and NHS costs.
I seem to recall ‘hydraulic’ locomotives, like the Western class 52 & Warship class 42, back in the late 60’s early 70’s, is it retro time for the railways now?
“BTW, non-availability of a regular and reliable rail service contributes to needs for private cars. ”
Exactly what the Beeching agenda was designed to achieve. The oil companies and MPs in the Midlands (who had ‘car and parts’ plants in their constituancies) wanted to get rid of ‘rail’ and they encouraged HMG to ensure that Beeching found this the most cost effective future formula.
My first boss in ICI Fibres shared an office with Beeching in his early days as a scientist at ICI Plastics. He told us: Beeching, (NOT an engineer) came-up with a wonderful idea to develop a ‘double-sided’ draw-frame. [One set of drives and gears down the middle and two sets of ‘processing rollers’, one on each side. Great! as long as you had operatives with arms 15 foot long, who could be in two places at the same time! It lasted about three hours and was then scrapped!
A Hydraulic accumulator has a pressurized pneumatic bag inside a chamber, the hydraulic oil fills the chamber squashing the pneumatic bag and hence storing energy. when the oil is needed, it can come out of the accumulator being pushed by the pressurized bag. I don’t know if this is how the train system works but it may answer Nick Doddle’s question.
An additional advantage my be achieved. If the final stop braking system, that is likely to be disc brakes, were to be hydraulic pistons instead of pneumatic pistons, as is common in many braking systems. The stored pressurised oil can be used to release the brakes instead of having to run an air compressor to release the brakes. It’s a win win situation.
The aim of the trials appear to be similar to that of the RSSB funded VLR (Very Light Rail) project. The VLR vehicle features 2 lightweight self-propelled bogies, each incorporating diesel-electric hybrid propulsion plus lithium titanate energy storage for regenerative braking and zero-emission launches from stations.
It will be interesting to see which technology proves to be best.