In-Vehicle Temperature Testing

Automobile owners expect their vehicles to operate reliably wherever they are driven, whether in the desert or in the arctic. Therefore it is imperative that automobile manufacturers verify the temperature operating ranges of components in a prototypical automobile in its final stage before production.

Application Summary
An automobile manufacturer needed to road test a new model of vehicle in extreme temperatures and collect engine performance data. Researchers planned road tests in Arizona and Alaska, in ambient temperatures ranging from -30^o to +55^oC (-22^o to +131^oF). To measure the prototype’s performance, test engineers needed to instrument six automobiles for more than 70 temperature measurements of each engine and its components including oil, coolant, engine-control unit, alternator, and other OEM parts.

Potential Solution
Previously, the automobile manufacturer utilized a DAT recorder that required a time-consuming effort to convert a digital tape to a workable computer file for data evaluation. In addition to being difficult to work with, the DAT recorder was bulky and prohibitively expensive for outfitting six cars.

IOtech’s Solution
To conduct the on-the-road tests, the manufacturer needed a data acquisition system able to meet a demanding set of performance criteria. These criteria included portability, operability from a battery, ability to accommodate and filter thermocouple signals, and a high-channel count. The system needed to run unattended by way of a simple setup process, followed by an easy download of the data to a laptop PC.

IOtech’s LogBook/300^™ stand-alone data acquisition system was chosen for the thermocouple application because it was cost effective, equipped to measure many thermocouples, fit easily in the car’s front seat, and provided quick download via a memory PC-Card (PCMCIA) and included LogView^™ Out-of-the-Box^™ software.

Technicians glued or taped thermocouples to engine components, or sealed them into engine pipes, and ran the thermocouples to a single position in the front seat where they were screwed into the terminals of the LogBook/300 data acquisition system. The LogBook/300 was powered via a DBK34A^™ DC uninterruptable power supply attached to the cigarette lighter. The DBK34A supplied necessary power to the LogBook/300 during power sags caused primarily by engine cranking. The LogBook/300 measured more than 70 channels at the rate of 1 Ksample/s.

To accommodate the thermocouple signals, the manufacturer used the DBK84^™ signal conditioning option. Six DBK84 modules expanded the system to up to 84 channels of thermocouple inputs. Noise reduction averaging was employed in the software setup to eliminate the noise induced by the automobile into the thermocouples. After averaging channels, stability was within 0.05^oC even in the electrically noisy engine compartment.

The researchers were also pleased with the LogBook/300’s optional LBK1^™ handheld terminal that allowed remote monitoring and control of the LogBook/300 while the car was on the road.

After each test, technicians removed the 20-Mbyte memory PC-Card (PCMCIA) from the LogBook/300 and quickly and easily transferred the data to a laptop PC. LogView Out-of-the-Box™ software, included with the LogBook/300, served as a simple method to graphically view the data and save it to disk, for later analysis using any post-acquisition analysis package including Microsoft Excel.

Conclusion
With nonvolatile storage of up to 250 million samples and a removable PC-Card memory, the LogBook/300 data acquisition system provided a low-cost-per-channel and easy-to-use solution. The system’s extensive signal conditioning options for many signal types including thermocouples, combined with an optional control terminal for triggering and reviewing required data, made it an effective tool for researchers measuring temperatures in the field.

The Logbook/300 collected on-the-road data that verified that the engine and its components operate according to expectations at extreme temperatures and that there are no unexpected problems: a mission critical to ensuring that the car will operate under all driving conditions satisfactorily.