To broaden the research areas beyond internal combustion engines, the Combustion Division has invested in and is currently building a hybrid test bed for experimental research on powertrains for passenger car sized vehicles. The test bed can be used for tests of a complete two wheel drive hybrid vehicle, and for tests of the components which are included in hybrids (e.g. internal combustion engines, electrical motors, exhaust systems, gear boxes, batteries etc.).
The test bed is not limited to one type of hybrid but has been designed to enable studies of arbitrary types, such as parallel, serial, range extender, and purely electrical vehicles.
The main components of the test bed include two wheel-dynamometers with inverter cabinets which accurately measure the torque and speed of the wheels. They are mounted on a 45,000 kg steel frame which hangs on sophisticated computer controlled air cushions. This removes disturbances from vibrating components on measurement data. A battery simulator is used to replace the hybrid battery under tests; it can be programmed with various simulations of aging, charging, discharging behavior and so forth. This means that the state of charge and the battery behavior can be exactly reproduced for each test. There are conditioning systems for controlling fluids in the internal combustion engine (eg. oil and cooling water) and an accurate measurement system for fuel consumption. The test bed is controlled from a master computer running a real-time operating system and this computer communicates with all other measurement systems. A FTIR is used for measurement of exhaust components, and there are data acquisition systems for both slow and fast data for eg. temperatures and cylinder pressures.
If a vehicle is used, it can be operated completely unmanned using computer controlled shifting and clutching robots in combination with software that models driver behavior, and thus tests can be precisely repeated. It is possible to program and test pre-defined driving cycles NEDC, FTP75 etc., or other arbitrary driving routes to study the influence on CO2 and emissions. This significantly broadens the system view, well beyond testing of internal combustion engines using engine test beds. The driving cycles can also be run without the vehicle. In such cases, only the hybrid powertrain connected to the dynamometers. This provides the possibility to test various hybrid configurations without the need to have the powertrain mounted in a vehicle. In such cases the vehicle and its inertia are modeled.
This test bed can be applied to a wide variety of interesting research areas including control strategies, vehicle emissions during transients, assessing various hybrid configurations, battery charge strategies, assessing alternative energy recovery systems and so forth.
This investment will broaden the system view by linking areas of strength within Chalmers (internal combustion engines, electrical motors, control, aftertreatment systems etc.).The new test bed is planned to be finished and put into operation in Q2, 2013.