Hybrid Electric Vehicle
Hybrid electric vehicles have arrived in my county. The new wave of mass transit technology has landed on my front door step. These electric hybrid vehicles operate on the same principles as the Toyota prius and the other popular hybrid models that are available today.
The big difference is, instead of a gas engine, this bus has a 5.9 L Cummings ISB common rail diesel engine. This diesel engine is coupled with a hi torque electric motor and power is blended to the wheels through an Alison CVT transmission.
The constant variable transmission is much like driving a snowmobile where you never feel the transmission up shift to the next gear. The transmission changes gear ratios on the fly to provide more speed at the optimum RPMs.
Electric hybrid diesels
Another thing that is different then on many hybrid vehicles is that the diesel engine never shuts off. In the best case scenario when the electric motor is driving the vehicle the diesel engine is still idling. The old transit buses received somewhere around eight to 10 miles per gallon.
The new hybrid electric transit vehicle will double the miles per gallon and should receive 16 to 20 miles per gallon. These specifications are for the ultimate of city driving. A transit bus is a stop and go vehicle and if it is lucky may reach 40 mph a few times during the day. Note that the batteries are on the roof of the electric hybrid vehicle and are recharged by engine braking.
Another interesting part about the diesel side of the vehicle is that this diesel engine manufactured by Cummings meets all of the latest alternative fuels emissions standards. You will not see belching black smoke from the fancy exhaust pipe shown in the picture below. The reason is that the 2009 standards include a particulate filter. This filter will pull most of the carbon from the exhaust being emitted from the tailpipe.
These particulate filters are new to the market and do require service. I am scheduled for training on this alternative fuels hybrid electric vehicle. But I did poke around and see that the diesel engine and emissions system comes with a regeneration cycle to be performed by the mechanic. When you enter the regeneration cycle, you are basically cleaning the diesel particulate filter.
Hybrid electric maintenance
When I read the maintenance manual about this procedure, it stated that the exhaust gases during this regeneration cycle could reach 1000°F. They stress that you perform the regeneration cycle in a safe area because of this exhaust heat. After I go through some training classes about these electric hybrid vehicles I will add more details.
Another interesting feature to the alternative fuels bus, as you can see in the picture below is that the windshield is massive and in one piece. The front windshield has a slight domed shape that provides better aerodynamics than a standard flat windshield. Also the headlights are halogen high intensity but low power units.
This hybrid electric vehicle is packed with new technology including Multiplex systems throughout. This is were about ten different modules communicate with each other via cabling (soon to be fiber optics). Multiplex systems replace wiring harnesses and relays. This is said to have reduced the wieght of the transit bus by more then 200 pounds.
Bringing the total vehicle weight in at 29,000 pounds. This is very impressive for a bus that is 40 foot long and seats just under 50 people and 2 wheel chairs. Also this electric transit vehicle is pre-wired for cameras and traffic light changing satellite systems. Looking at the electronics is similar to looking at electrical systems on the space shuttle.
For more information about interesting vehicles that provide power from something other than straight up gasoline, Please visit my alternative fuels section.