Harnessing the Power of Embedded Design to Develop an Innovative Measurement Sensor for Automotive Test Systems

 Luca Marassi, Loccioni Group

"We were able to design an innovative automotive test system based on NI technologies characterized by their flexible, reliable, and easy-to-use framework."

- Luca Marassi, Loccioni Group

The Challenge:

Designing a flexible and reliable automotive test system for measuring and charting the flow rate of diesel engine nozzles.

The Solution:

Using the NI LabVIEW graphical programming environment to design a control program for data acquisition, management, processing, and reporting.

Author(s):

Luca Marassi - Loccioni Group
Alessandro De Grassi - Loccioni Group
Francesco Siano - Loccioni Group
Carmine Ungaro - Loccioni Group

 

NI Gold Alliance Partner Loccioni Group is considered a flag-bearer for Italian innovation because of its reputation for developing custom technical solutions to ensure quality, comfort, and safety in many areas. We work closely with universities and research centers to develop and implement turnkey systems using technology. We have applied our expertise in measurement and test for quality control, automation, ICT, energy, and service across a range of industries including automotive, electrical appliances, environmental, health, and manufacturing. In our labs, quality is emphasized as critical, because we strive to be the highly specialized experts in the design and deployment of automated test and quality control integrated systems. We focus primarily on two industries: automotive and electrical appliances. Currently, we implement custom lines and test workbenches for partners in the automotive component manufacturing industry. 

 

Researching, Developing, and Producing

Our research and development lab is the “beating heart” of the group’s ideas. The lab is flexible and adapts quickly to tackle challenges in the automotive field. Moreover, it is used to test and verify new solutions and perform internal-use and end-user measurement campaigns. Areas of focus include pressure measurements, volumetric flow rate, mass flow rates, and operations of nozzle characterization. The latter gave birth to the Mexus project, an innovative, nozzle-specific measurement system development project based on National Instruments technology.

 

 

This project originated from the need to measure the flow rate of diesel engine nozzles with a detailed quantification of the fuel injected during a single injection. The final product is an instrument used worldwide by injector manufacturers for end-of-line production tests. Our goal was to provide a low-cost product with cutting-edge technology and better performance than other available instrument. 

 

The solution is a reliable product capable of accurately determining the two fundamental parameters characterizing injectors: the flow rate injected for each shot and the chart of the instantaneous flow rate. The instrument provides the measurement of the fuel quantity injected in each single shot event up to a maximum of 10 events per revolution (also known as multi-injection). By simulating the engine operation at 3,000 rpm, the readout value injection for each revolution can be easily detected by the system, which provides the quantity of each fuel injection in real time. The innovative aspect of this project is the calculus algorithm used in the solution. The system acquires different analog signals and processes them in real time, providing the user with reliable test results up to the injector functioning rate of 50 instantaneous values per second. 

 

The system is also able to determine how much fuel is dispensed in each injection. This information is significant for injector characterization because emissions regulations are becoming more restrictive. Consequently, it is important to provide manufacturers with more detailed information to gain high-level combustion, reducing either fuel consumption or the quantity of pollutant gas within the environment. 

 

Technology Integration

To ensure measurement reliability, we used National Instruments products to support the project. The design of the Mexus control program used LabVIEW to manage data acquisition, processing, and reporting.

 

 

One critical element of the Mexus system is the injection chamber, the cylinder conveniently provided with control sensors and valves where the fuel is injected and the specific measurements are performed. The injection chamber and its control system were modelled with the LabVIEW Control Design and Simulation Module. In this stage, simulations were performed on a PC using the LabVIEW graphical programming environment. During prototyping, the same PC and Windows platform is maintained through an NI PC-based data acquisition board that performs functional characterization and validation. This important development stage of the project highlighted the need for a more refined chamber injection model. This was determined by using the LabVIEW System Identification Toolkit, which made it possible to obtain the transfer function of the injection chamber and consequently design a suitable control algorithm. To enable

 

To enable a large scale deployment, we needed a hardware device with failure-free technology that was capable of operating around the clock, offered a compact form factor, and suitable for an industrial environment.

 

We chose the NI CompactRIO system to ensure maximum compatibility with the software. This hardware helped us make a quick shift from prototyping to deployment as well as ensured that we met the sampling rate requirements and the real-time, deterministic control of the process. 

 

In the solution, the user interface is controlled by a touch panel computer equipped with a Windows XPe OS programmed using LabVIEW and with an Ethernet connection to the CompactRIO. When developing our solution, the most important advantage was the use of a single development environment for the design, prototype, and deployment phases. This advantage reduced the need to interface with third-party programming languages. LabVIEW also provided great flexibility for development integration, ease of use, and hardware control. 

 

The Mexus final product guarantees the highest reliability in test operations. The accuracy of the measurements is due to the introduction of innovative working methodologies that ensure test compliance with the most restrictive regulations. We were able to design an innovative automotive test system based on NI technologies characterized by their flexible, reliable, and easy-to-use framework. 

 

Because of our know-how and technological partnership with National Instruments, Loccioni Group has provided the automotive world with an innovative product that delivers excellent test standards with no machine downtime and an easy-to use interface.

 

Author Information:

Luca Marassi
Loccioni Group
Tel: +39.0731.8161
l.marassi@loccioni.com

The injection chamber and its control system were modeled using the LabVIEW Control Design and Simulation Module.
The Mexus control program uses LabVIEW to manage data acquisition, processing, and reporting.