Case Study : Hybrid Bus

Project Outline:

• Produce and demonstrate a clean diesel electric mass transit vehicle
• MIRA lead (Terrafix, Alexander Dennis, MST & Beta)
• Targets
  • EURO IV Emissions
  • 30% Fuel saving (compared to standard bus)
  • Full Public Service Ready Vehicle

•We are part of a consortium bidding to develop a diesel/electric bus.

•The bus will have on-board ‘telematics’ functions.

•MIRA will provide the electrical system architecture design and controller.

•The CPU will control the powertrain and integrated fleet management telemetry.

•This diagram shows you an outline of the vehicle systems and the responsibility of the patners

•Beta having responsibility for the batteries and chargers

•MST having overall powertrain responsibility

•Terrafix supplying the telematics unit providing location based data

•Alexander Dennis supplying the driver interface

•And MIRA developing the VMU, auxilliary power systems and integration of the overall electrical systems

Design Approach

• Specification/Target Setting
• System Modelling
• DV (Design Verification) Planning
• Hardware Development
• Software Development
• Lab & Vehicle Tests

Preliminary Specification

• Mass – 12 tonnes (unlade weight)
• Max Power – 90kW
• Max Acceleration – 2m/s
• Driveline Efficiency – 80%
• Aux Electrical Load – 20kW

Preliminary Simulation Assumptions

• Vehicle taken as fully laden at all times!
• EV mode auxiliary power control assumed to give acceptable acceleration
• Small Capacity Diesel Engine

Planned Test Route

Specific Test Route in Coventry Chosen The Route was ‘Zoned’ to Provide Control Strategy.

Road Test Data

• Peak load capped at 90KW
• Base aux load 20KW is significant energy draw
• Regenerative energy not significant
• EV mode based in Coventry city centre (i.e. 15mins drive time (*2))
• 6kwh of battery energy used  in and ou
• t of city !!!