Powertrains today require complex controllers that manage ever-larger volumes of data. Although they provide better fuel economy and lower emissions at the same power, their complexity also brings risk. "There are tens of thousands of variables in today’s calibrations. If even one of them is not quite right, it could be either completely benign or completely disastrous, requiring a recall campaign," explained Paul Kilmurray, Powertrain Control Specialist for Mahle Powertrain. Reducing the risk of recalls and helping calibration engineers avoid data overload motivated Mahle to develop its ProLogiq Integrated Data Acquisition and Analysis process. Offered as a service rather than a product, ProLogiq incorporates Mahle’s proprietary software using The MathWorks' Matlab computational engine. It provides Mahle the ability to quickly develop customized analysis scripts for new control systems and automating the data analysis process.
ProLogiq contrasts with conventional calibration validation methods. Today, manufacturers typically equip a fleet with data loggers and review the large amounts of data either manually or, at best, with a semi-automated routine. They may run an event trigger system that records only specific "snapshots." While such methods are effective at exposing false fault detection, according to Kilmurray, "detecting transients or intermittent issues may be missed. They are labor-intensive, and it is often difficult to spot trends." For the off-highway world, Kilmurray believes these conventional methods will require a huge investment in engineering capabilities. On-highway heavy-duty engine providers will start to ramp up to meet the On-Board Diagnostic II standard (OBDII) over the next few years. Mahle expects that off-highway will be forced to follow before too long.
Kilmurray says the latest data collection equipment can collect a vast amount of data. For example, Mahle’s own MDR-2 can record more than 500 channels at high sample rates—engine synchronous or every 10 ms. The problem is the time required to analyze all that data. "Since ProLogiq is automated, the volume is irrelevant." The process also looks at continuous data streams rather than snapshots, and ProLogiq detects transient anomalies. Problems are detected long before they trigger the Malfunction Indicator Lamp (MIL) as the process continually calculates the status of the system malfunction monitor. "The engineer can rapidly identify any monitor tracking close to a malfunction status," explained Kilmurray. "This gains early detection of potential issues. The process performs best when collecting data over larger fleets, capturing a wide range of environmental conditions and driving cycles." Mahle cites one example of a project for a major automotive OEM in support of a full OBD investigation. Creating a 17 GB database with over 2000 drive cycle recordings on three vehicles—a total of more than 50,000 mi (80,000 km)—they discovered four MIL issues. This helped the OEM avoid a potential $100 per vehicle warranty cost when compared with an average industry cost.
Since it is a service, Kilmurray stresses calibration engineers avoid data overload. “Rather than the engineer looking for the needle in the haystack, we can show him where the needles are and he can examine the issues,” explained Kilmurray. He says that consistency is another feature of the service. As calibrators move from project to project, the simple data transfer interface to ProLogiq remains the same. “Calibrators can calibrate rather than write scripts or macros.”
Matching the needs of their customers, he reports quick data turnaround. While most OBD validation programs look for monthly reports, Mahle has accompanied customers on calibration development trips and even processes data overnight to assist in the development task. Data can be stored for reprocessing at any future time, providing the ability to do what-if studies. Powertrain calibrations can be read in, meaning that engineers can re-evaluate data with modified calibration values. It works with popular calibration tools, such as ETAS INCA or ATI Vision products. Recorded data files (from any worldwide location) are transferred to Mahle, batch processed, and results are databased. “We use existing data sources where possible. Often, there is no need for new logging equipment,” said Kilmurray. Data can be recorded from other sources, such as vehicle location GPS units synchronized with engine data recordings. “This is a likely scenario in off-highway applications.”
Data reporting includes a summary of vehicle usage, drive style analysis, mileage accumulation, and other specific engine control metrics. Primary applications that Mahle offers ProLogiq for include calibration development, vehicle fleet analysis, and OBD, including rate-based monitor analysis. “Most of the work we have done is for OBD validation, both for gasoline and diesel,” remarks Kilmurray.