By Halsey King

Electric Bus Fever

October 13, 2021

Coach Corporation using an Edison electric bus from 1915, Library of Congress

Every truck, bus and automotive engineering magazine that arrives at my office is filled with articles, ads and helpful hints about some type of electric vehicle. The articles also discuss the remanufacturing of the earlier battery packs, as well as looking into the many “new” vehicle manufacturers who are entering this fast-growing field. Some have never made commercial vehicles. Like most of CTAA’s members, buses, of course, are at the center of my interest and they have been getting tremendous attention in recent months.

Historically, the 1915 Edison bus, which used lead acid batteries, was eclipsed by the 1920 Flexible/Fageol type electric motor buses, as used by Louisville Railway (now Transit Authority of River City, “TARC”). Photos of these buses still adorn the walls of TARC offices in Louisville, Ky.

In more recent times, I believe school bus engineering groups started to design electric platforms around the 1990s and are now positioned to be on a rapid trajectory upward. Since school buses are America’s largest public fleet for children, with more than 420,000 in service, the electric vehicles do have a long way to reach parity with current gas and diesel. However, they can help move children away from breathing gasoline and diesel exhaust.

Transit buses have had several models come to the forefront in the last five years and they are gaining in popularity nationally and abroad. China is believed to have the world’s largest fleet of electric powered buses.

When I say “electric powered,” I mean buses that are equipped with a CNG, gasoline, diesel or propane fuel powered engine that is connected directly to an electric motor. In modern engineering circles, we call this type of drive systems “hybrid.” In reality, this drive system has been around since the 1940s and powered most railroad locomotives and a number of U.S. Navy submarines.

The other “electric powered” vehicles are the battery-only type, which again have been around for more than 100 years in America. In 1905, no less than five different car manufacturers were making battery powered cars, including Ford, Edison, the Detroit Electric, and many more.

When we have a bus (including a van or cut away paratransit vehicle) that has no engine and is driven only by the electric current from the battery systems, we refer to it as a battery electric bus (BEB).

BEB buses produce a lot of “torque” or twisting motions to a drive shaft, in order to get the vehicle to start rolling and sustain its street operation until the battery drains like a cell phone. To some, this calls for a more powerful battery, which could be a larger size (and heavier) or, to others, a different chemistry or technology, which is currently being invented behind closed doors, at present.

I firmly believe we will see the “BEB combination” become the main power choice for our size of bus in the future. But, that does not end the conversation because several other bus related systems will be changing and invented over time.

WHAT’S COMING


Depending upon who you talked to last, or what research you may have read in an article, there certainly is a technology race happening across all automotive sectors. I believe it is far greater now than one hundred years ago, when more than 400 automotive car, truck and bus manufacturers were leap frogging each other’s advancements. Fortunately, we will get to see these advances at upcoming trade shows and media events. At present, my crystal ball suggests we may be seeing such things as:

  • A possible move away from some types of lithium batteries, to ones that may offer longer life, less heat potential.
  • Improved high voltage and low voltage wiring systems (i.e., HV/LV).
  • Vast improvements in HV connections, junction blocks and other integrated control units, over those made only five to seven years ago.
  • A broad application of new and replacement parts for battery pack remanufacturers.
  • More companies are looking to remanufacture these five to eight year old electric vehicle batteries (and yours in the future).
  • Lighter, yet stronger, composite structures to enable longer life on bus operations, over dirt, gravel, and other bad roads.
  • More precisely engineered electrical motor housings and stator windings, to withstand harsher operation and heat buildup.
  • The use of “cement crackers” inside the electronic control assemblies to add longer lifecycles to the charging events.
  • We will see less fan belt driven assemblies, as those become electrical motors and/or are driven by separate components.
  • Newer inspection and test equipment for the bus maintenance technicians. These will be more precise and offer a high level of protection against electrical shock.
  • A possible move away from mileage-based bus inspection and service to hourly or system defined periods.
  • And so much more.

STAFF TRAINING


Moving from gas/diesel hybrid buses has shown that most fleets handle this operation quite well. However, there are subtle changes that must be taught so that new operators become comfortable with hybrids and BEB’s. Some of these are:

  • Noise levels change when the engine, rear A/C fans and heater fans are switched off and on. These can be the only noise passengers hear.
  • When these fans are turned off and the bus is driven at low speeds, mechanics can diagnose gear, brake and bearing noise easier.
  • The brake friction pads can last longer when the motor is used to check the bus speed.
  • In terms of shop lexicon, everyone needs to remember the engine drives the electric motor, on hybrid buses.
  • Passenger heating is not as big a challenge on a hybrid bus as it is on battery electric buses because of the way heat is generated on each one. Smart managers may choose to specify additional heating systems.
  • High torque being applied by quick start-offs will be seen with excess wear on the rear tire tread very quickly.
  • Battery-only buses can be heavy, and suspension may show signs of early and often wear.
  • Any loose battery or connecting wire can present a big problem.
  • Any corrosion on frame connection points, high power connection, or in any low voltage cable cannot be allowed.
  • Motor and inverter attaching bolts and nuts need to be retorqued on a regular basis.
  • Any oil leaks at the seals of the motor, inverter or differential needs to be addressed quickly.

NOTE: These tips are provided only for the sake of driver and mechanic awareness. Always use the specific information from your bus manufacturer for driver training and mechanics inspection guidelines.

SHOP TOOLS AND EQUIPMENT


While most of the paratransit fleet shops will not be required to make large scale changes (like those that occurred with CNG fuels) you may find it necessary to make sufficient changes to the facility electrical grid in order to keep equipment at the proper state of charge.

SAFETY

Of primary concern with all types of electrical buses is the potential for injury and death on the shop floor. Electricity by its very nature will cause first, second and third degree burns. It can also stop the heart!

For those reasons, several organizations are developing guidelines and standards for people working around, and directly with, electrical power. Myself and a colleague will be presenting this information, and much more around electric buses, at CTAA’s EXPO next month. If you have, or plan to acquire, electric buses of any type, we encourage you and your mechanics to attend this special training. My colleague and electronics specialist, Mike Brock, will provide information that includes systems, controls and methods in general. We look forward to seeing you there!

About the Author: Learn more about Halsey King and Associates, Inc.

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The Community Transportation Association of America (CTAA) and its members believe that mobility is a basic human right. From work and education to life-sustaining health care and human services programs to shopping and visiting with family and friends, mobility directly impacts quality of life.