TEMPERATURE CONTROL FOR DYNO TESTING OF INTEGRATED STARTER GENERATORS

The Integrated Starter Generator (ISG) is one of the most important components of a hybrid powertrain. It both generates energy from the internal combustion engine (ICE) to charge the batteries within the vehicle. During its operation the ISG generates heat which is normally removed by the vehicles internal coolant lines. During different test bench processes, a JULABO temperature control system replicates these coolant lines.

JULABO’S SOLUTION APPROACH
A PRESTO A45 Highly Dynamic Temperature Control System (working temperature range of -45 °C to 250 °C) in combination with a flow meter/fluid by-pass will maintain the temperature of the ISG while at the same time precisely regulating the flow rate of the fluid.

EXEMPLARY TESTING PROCESS
A testing requirement for the ISG is a power generation test carried out at two speeds. For this test, the temperature of the ISG is set to 65 °C. Prior to the initiation of the ISG power generation test, the PRESTO A45 was maintaining 65 °C with 30 % (1.8 kW) power. As soon as the ISG was brought up to 2500 rpm, its own heat generation required the PRESTO to reduce its power down to between 0-2 % (0.12 kW) heat input to maintain the consistent 65 °C. During the increased heat generation at 4800 rpm the ISG required active cooling of 3-4 % (0.14 kW) cooling input to remove heat from the generator (the negative % on Chart 1 denotes cooling).

CONCLUSION
Manufacturers of ISG’s place their product through rigorous test conditions such as different temperatures, speeds, power generation and long term stress testing. On the test bench the manufacturers need to precisely replicate automotive coolant supply so that generated heat
can be removed from / added to the ISG to simulate real world conditions. This is where JULABO can help with its PRESTO Highly Dynamic Temperature Control Systems.