A new electric powertrain, dubbed MESA™ (Modular, Electronic, Scalable Architecture) powertrain, has been designed for use in series hybrid, all electric and fuel cell mass transportation buses, large utility vehicles and other automotives. Said to provide fuel economy on par with SmartCars, the MESA powertrain features highly modular systems electronics, an intelligent control software platform (see Figure 1) and the industry’s first scalable, field installable energy storage system that can be configured, depending upon users’ requirements, to provide 25, 50 or even 100 miles of initial travel in pure electric mode with subsequent travel in hybrid mode.
Combined with an onboard microturbine generator for extended range, MESA is expected to dramatically lower emissions and reduce operating costs for buses and large utility vehicles by 50 percent or more vs. standard diesel powertrains. MESA is slated for initial deployment in mass transportation hybrid buses in China, with U.S. implementations following.
“Until now, powertrain developments have been initiated more from a mechanical systems integration approach, resulting in marginal fuel economy advantages and relatively few miles of electric range,” said Marv Bush, CEO of Adura Systems, the company that created the MESA powertrain. “Adura’s team of world-class software and electronics engineers took a ground up approach with MESA, creating intelligent electronics, software and energy storage technology that is lighter weight, incredibly fuel efficient and at a lower total cost of ownership vs. other hybrids currently offered for heavy duty vehicles. While our product can scale to many types of automotives, we are first pursuing heavy-duty buses and large utility vehicles as there is great demand from municipalities and government institutions for better solutions at lower acquisition costs that provide near zero emissions, greater fuel efficiency and reduced maintenance expenditures.”
Innovative Architecture
MESA consists of several key modules backed by electronic and software technology, which Adura claims as having nearly 10X more electric range vs. other hybrid powertrains for mass transportation buses and large utility vehicles. These modules include: mCtrl, mStor, mBridg , mGen and mDrive.
mCtrl is described as a first of a kind systems control that optimally and intelligently manages and controls all aspects of the modular system. Designed from the ground up, the system features power management electronics and component electronics that control the MESA modular energy storage system (mStor), electric Generator module (mGen) and the electric motor module (mDrive). mCtrl is designed to ensure high reliability, overall system efficiency, serviceability, and fault tolerance.
mStor is an economical, scalable and user installable energy storage system that can be configured to provide 25, 50 or 100 miles of electric range in heavy transit buses. mStor modules can be easily added or subtracted to meet users varying electric mode requirements (see Figure 2). The mStor modular battery system is fault tolerant, chemistry agnostic and allows the mixing of battery chemistries within the storage system.
mBridg is the interface between the system, the bus accessories and infotainment. It provides the driver interfaces and the near real-time automated systems maintenance diagnosis and reports for the driver and maintenance support staff.
mGen is a 60 kW microturbine generator that is intelligently used to charge the energy storage system when low state-of-charge conditions arise. The flex-fuel microturbine weighs less than 500 lbs. vs. diesel engines that can weigh more than 3,000 lbs. The microturbine can use diesel, liquefied petroleum gas (LPG) or compressed natural gas (CNG). It has only one moving part and only requires service about every 8,000 hours of operation.
mDrive is the electric motor that provides propulsion to the vehicle and provides regenerative breaking. The system motor is optimally controlled by mCtrl to deliver smooth, efficient acceleration and breaking. There is no transmission—the motor connects directly to the driveshaft. Figure 3 shows the relationship of these modules from a hardware perspective.
Reduced Emissions
Adura’s MESA meets U.S. 2017 CAFÉ and Euro VI standards. Due to its electric range and emissions friendly range extender, the company estimates that MESA can save 37,000 tons of emissions per eight-year bus life. As an example, in China there are 1.3 million buses. If the existing diesel powertrains were replaced with MESA, that could equate to about 6.1 billion tons of reduced emissions per year.
MESA delivers improvements in emissions and fuel economy as follows:
1) City buses can run approximately 100 miles/day in pure-electric mode;
2) City buses traveling 130 miles/day with a 100 mile energy storage capacity will get an average of 50 miles per gallon (MPG) vs. traditional buses which operate around 5 MPG. Emissions may be monetized at a cost of $10/ton. If so every bus containing MESA could generate $370,000 from emissions’ carbon credits.
First Deployment
The first deployment of MESA is to occur in China within the next 12 months. This milestone follows a partnership agreement formed between Adura with the China Automotive Technology and Research Center (CATARC) in May, 2008. Adura is also negotiating contracts in the U.S.
Mr. Yonghe Huang of the China Automotive Technology and Research Center in Tianjin, China stated, “Adura’s powertrain integrating the turbine in the hybrid-electric technology system will become a revolutionary ‘green’ ground transportation propulsion system for buses. The Chinese government is enthusiastic to support energy-saving technology for the automotive industry. We look forward to the technical cooperation with Adura to contribute to China’s energy-saving goals in the automotive industry.”