‘人と環境に優しい、ハイブリッドバス’のKing Long Hybrid Citybus
Friday, March 5th, 2010For some folks who have forgotten about the King Long Hybrid Citybus from China that landed in Singapore last year, it was spotted on test at Boon Lay on 4th March at noon. One photo of it on the road:
King Long, model XMQ6121G. Series-parallel system.
A series system is basically straight through hybrid, the diesel engine is small in size and runs the generator, which charges the batteries, and electric motors run the axle with power from the batteries only. There is no direct drive linkage. Examples of these on buses are the Alexander Dennis Enviro 400H and Mitsubishi Fuso Eco Hybrid (BJG-MP37T).
The parallel hybrid system is an added hybrid for a existing framework, little modification to the overall drive. A larger diesel engine runs the drive line, in the middle a small generator is driven to provide current to the batteries. The batteries assist in braking functions and regeneration from engine braking forces, can power lighting and air conditioning of the bus. Example is the Alexander Dennis Enviro 500H.
Series-Parallel is somewhat in the middle, a switch can automatically adjust power between running from batteries or from engine directly. Toyota uses this on their hybrids.
Older hybrid systems included the HIMR from Hino Motors Japan. HIMR stands for ‘Hybrid Inverter Controlled Motor & Retarder System’, which offers the first production hybrid buses in Japan since 1994 (test unit in 1991). Toei Bus (都営バス) is the largest operator, and these buses served many years on as the ‘低公害バス’ (Low Emission Bus). These buses use a three-phrase electric generator and batteries to store energy during braking and use them for power take-off, so as to reduce emissions. It is very successful and technology used later on the Blue Ribbon City hybrids. Production for these buses lasted from the U- (Euro 1 equivalent) to the KC- (Euro 2 equivalent).
Mitsubishi Fuso also had their MBECS (Mitsubishi Brake Energy Conservation System) on some of the modified Aero Star city buses. They use a hydraulic system to store energy during braking and release them when the bus moves off, working like a rubber band theory. These buses are produced from 1995 to 2000 and span only one emission era (KC/Euro 2 equivalent).
Japan currently has two hybrid citybus models in production, the Hino Motors Blue Ribbon City (BJG-HU8J) and the Mitsubishi Fuso Eco Hybrid (BJG-MP37T). Both would be EEV equivalent if certified, so far no units have done so and all production units remain Japan domestic.
Hybrid buses especially those in Japan carry hefty price tags, their batteries are also regularly criticized for being un-green. However in the effort to clear the city air, we may have dumped more waste into the manufacturing areas, away from the city. Hybrid technology continues to improve, we do hope to see electric vehicles on the roads one day, when we can truely enjoy a zero-emission road environment.
Saying that much, I have yet to see large amount of technology like the Japanese from the Europeans. One benefit that Japanese operators have when it comes to hybrid buses are incentives from the government. For every ‘eco-car’ purchase there can be up to 35 percent rebate. That is also why the rate of hybrid introduction is very high in Japan.
Tokyo, Osaka and Nagoya have passed the NOx/PM law in Heisei 17 (2005) for all diesel vehicles. Vehicles with Gross Vehicle Weight (GVW) more than 3.5 tons and of emission class KC- and below (Euro 2 and below) are banned from entering the metro areas and towns/cities designated by the law. Vehicles that are above the emission limit of (5.9 grams per kWh max, 4.9 grams per kWh average) for NOx are hence affected. If the owner of the affected vehicles wish to continue using them in the metro areas, they must be fitted with Diesel Particulate Filters (DPF), a popular item in the market now. Offenders of this law are fined not more than 500 thousand JPY (7800 SGD).
Vehicles that were at that time less than 12 years old are allowed to be used up to expiry of their license (which is 12 years in Japan). Many U- and KC- buses of Toei Bus were scrapped or disposed to countryside companies to continue service. Many other Non-Step buses of various companies just meeting 12 years old are hence disposed off. These are perhaps the earliest cases of disability-friendly buses being disposed off in the World, particularly low entry/floor buses being disposed off in bulk.
We do not have such laws in Europe or Asia, but its an eye-opener nonetheless, not to mention a costly move by the government to dispose off vehicles at such a fast rate.
An exciting bus model event coming your way soon. Stay tuned here for more updates!
