Railcar builders to introduce new DMU designs for domestic and overseas markets

[bikkuri bahn]

TOKYO -- Japanese train builders are readying fuel-efficient, diesel-powered cars in anticipation of brisk demand both in Japan and abroad.

 

Kawasaki Heavy Industries has devised a new train car equipped with a diesel power generator. Electricity from the engine moves the motor that turns the wheels, rather than the diesel engine propelling the wheels.

 

The company had virtually withdrawn from diesel train cars after supplying to Indonesia's national rail network during the 1980s. Kawasaki Heavy will shift to full production and sales of diesel trains with the rollout of the new model.

 

The new train's structural similarity to conventional electric train models makes it possible to carry over a majority of the parts, saving on production costs.

http://asia.nikkei.com/Japan-Update/Japan-rail-car-builders-rolling-out-next-gen-diesel-trains

[cteno4]

Nice convergence of technologies to make a more robust and and easily maintained system. Diesel generator can just be replaces and old one refurbished anywhere.

 

Jeff

[miyakoji]

This reminds of the JR East request for proposal we had some threads about before

• http://www.jnsforum.com/community/topic/10076-jr-east-solicits-tenders-for-new-diesel-railcars/
• http://www.jnsforum.com/community/topic/8875-possible-scoop-jr-east-to-request-tenders-for-new-rolling-stock-for-hachinohe-line/
• http://www.jnsforum.com/community/topic/9457-procurement-of-diesel-railcars-for-hachinohe-line/

I never heard anything else about this, has it shifted from possibly Alstom or Bombardier to the much more likely KHI?  The Japanese Wikipedia page for the KIHA40 says that JR East still has 168, 77% of the 219 from JNR (it also says that JR West has 98% of their JNR KIHA40 inventory, and JR Kyushu 100% of theirs )

[HantuBlauLOL]

DEMU eh?

[Sacto1985]

I think one issue that could make this new DMU design difficult--especially if it's a diesel prime mover driving an electric generator to power electric traction motors--it that the DMU has to be fairly small in size (about the size of the current JR East KiHa 110/110, JR West KiHa 120 or JR Kyushu KiHa 125). I'm not sure if they can design the whole power train system that small, given the power needed is around the equivalent of 330-350 ps.

[Kabutoni]

Huh. That's the same drive train setup the new Nissan Note E-power uses. This car produces 109hp/254Nm at the wheels (electric motor) and would be sufficient for a train on all axles driven. The setup is very compact, very fuel efficient, and would probably just fit fine under the carbody of a DMU. It's basically just slapping a generator and some batteries under an existing EMU design.

[kvp]

If someone was following the british DEMU/EMU tenders and read about the Hitachi trainsets, then this is not a surprise. As many british DMU-s were actually diesel electrics since the Thumpers (br class 207), this technology has quite a past and it looks like Kawasaki finally rediscovered it after Hitachi built a whole fleet of them for the UK.

 

For size and weight problems, the trick is having a single prime mover. For a hydraulic DMU, the usual configuration is one motor for each bogie with a hydraulic torque converter, while an electric DMU can have a single diesel motor-generator setup and electric motors in the bogies. The weight of a single motor+generator combo could be much lower than a double motor+torque converter design. If you add some batteries, you get a hybrid system with a smaller diesel generator that would be needed for quick acceleration as the extra power could come from the batteries. Potentially this also allows higher accelerations and better fuel economy than with a diesel hydaulic system. The main reason why the diesel hydraulic system was choosen in the past was the easy maintenance as almost no electronics were involved in the drivetrain. Today electronic traction control is much more advanced and also smaller, lighter, more efficient and reliable, not to mention available off the shelf due to modern EMU technology.

 

ps: a properly designed DEMU could be extended for DC catenary or 3rd rail operation without extensive redesign or even AC catenary support added if it's planned for in advance

[katoftw]

I think one issue that could make this new DMU design difficult--especially if it's a diesel prime mover driving an electric generator to power electric traction motors--it that the DMU has to be fairly small in size (about the size of the current JR East KiHa 110/110, JR West KiHa 120 or JR Kyushu KiHa 125).

That is not an issue.  Those smaller DMUs currently service low passenger usage rural lines now that are not electrified.

[bikkuri bahn]

I recall reading an article about an engineer (I think he was/is working for Niigata Transys) that after the breakup of JNR, was advised not to pursue a career designing diesel railcars as there was seemingly no future in that field, especially with the closing of so many rural lines. Perhaps his decision to stick with it is now vindicated.

Edited December 7, 2016 by bikkuri bahn

[railsquid]

If someone was following the british DEMU/EMU tenders and read about the Hitachi trainsets, then this is not a surprise. As many british DMU-s were actually diesel electrics since the Thumpers (br class 207)

 

Apart from the various Southern Region class 20x series, pretty much all British 1st and 2nd generation DMUs are diesel-mechanical or diesel hydraulic (with the exception of express sets like the Blue Pullman, Voyager, and possibly the Underground D stock conversions).

[kvp]

Actually Niigata Transys went the other way and are using low cost, off the shelf diesel hydraulic systems, found in boats and skid steer loaders. They are actually following the JNR tradition in this regard, but added modern technologies, like a CAN bus for easy multiple unit control and a mechanical clutch for increased efficiency after the 1:1 ratio is reached by the hydraulic torque converter. Auxiliary power is bled off the main hydraulic circuit with a continously slipping hydraulic clutch, essentially a constant speed, variable power diesel hydaulic generator. This part is not so efficient, but very simple, cheap and easy to maintain.

 

DEMU technology is better, but only because it lends itself to hybrid systems with battery power storage for added boost during acceleration and energy recovery during braking, not to mention hybrid cateneray-electric operation. All require efficient high current bidirectional traction control systems, that were not yet available at the time of the JNR breakup.

 

For larger trains, the DEMU technology is a good approach. As commercial diesel electric hybrid trucks become more common, the price for smaller systems will be low enough for short single car sets to be built as diesel-electrics.

 

ps: The oldest series of internal combustion electric DEMUs i know of was the 1906 De Dion-Bouton system trains built for the ACsEV local railway in Arad.

an original motor-generator as built: http://iho.hu/img/vasut/1311/131118_acsev/03.jpg

a surviving Mc-Tc short set that was modernised in 1959 (BKV museum stock): https://www.youtube.com/watch?v=e1XwNzM-2Gg

[Sacto1985]

However, given that this proposal comes from JR East, they must design the DEMU to operate in the very cold conditions of Akita and Aomori Prefectures. And JR Hokkaido may be interested for operations on their remaining profitable lines during the winter months.

[katoftw]

All JR Easts other diesels have been designed to deal with cold conditions.  Why would these be any different?  Yes different tech, but still the design philosophy will be the same.  Unless you are not just stating the obvious and are meaning something else?