Develop and commission a fully automated dynamometer test rig for Integrated Starter Generators
Benefits for the business as a result of delivering this solution include:
- Superior performance, with significant cost-benefit gains
- Better simulation of rapid changes of gear, speed and load in the vehicles
- Most advanced range of testing capabilities in the automotive industry
- Easy access to multiple data sets to enable in-depth understanding of the unit under test
- Automated tests with constant safety monitoring allows other tasks to be done in parallel
Background to the project
Controlled Power Technologies Ltd (CPT) requirement was to develop and commission a fully automated validation test rig for replacement ISGs used in hybrid vehicles. We partnered with Incotech, specialists in purpose built automation, assembly and testing machines, where our role was to provide a software application to simulate the use during the lifetime of the component. The test rig needed to test the ISG’s performance at different temperatures, speeds and power generation requirements. It needed to be flexible to allow the operators to change any aspect of the test procedure to suit the unit under test.
The test rig is set up to enable drive from a motor to be transferred to the ISG under test via a belt and pulley set. The ISG is situated within an environmental chamber to allow for varying temperatures to be set throughout testing. There is also a load bank that allows the simulation of the ISG in generation mode, acting as a store for the energy generated by the ISG.
It was important to ensure the temperature of the ISG was maintained throughout a test, so a separate coolant circuit enables this with control managed by the software.
“This project is exceptional – the test cycle specifications are extremely arduous. The wide range of test temperatures, speeds and power are unusual in the automotive industry. The rig is designed to better simulate rapid changes of gear, speeds and loads in the vehicles which isn’t currently available on the market. One major automotive manufacturer has now raised their own specifications.”
Product Evaluation Manager,
Controlled Power Technologies Ltd (CPT)
Solution in Detail
Below is a diagram to illustrate the test rig setup;
The NI Compact RIO is responsible for all signals coming into and out of the system utilising the FPGA and real time operating system. The compact RIO platform enables the system to be run headless, without the PC being connected.
The main challenge with this project was ensuring all communication links with the hardware were reliable, responsive and synchronised. To ensure this, all systems were commissioned individually prior to being brought together to perform system testing. This ensured the reliability and responsiveness of each piece of hardware on an individual level, so that when system testing commenced the focus could be on synchronisation alone.
A separate application was developed and commissioned for the PC to allow the operator to setup test profiles and start and stop tests. It also gives the operator a live picture of the current cycle graphically and how many cycles have been completed.
The process for an operator to carry out a test is detailed below, showing what the system has to do at each step.
The data outputs from the system included the following;
- Cycle data captured at 10Hz
- Critical error data capture at 1kHz 5 seconds before event and 10 seconds after
- ISG CAN message data during the cycle
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