Tuesday, June 5, 2007

6 The Core of SDM: Systems engineering at work at Cummin - SDM Pulse, Summer 2007

Editor’s note: The core courses for the MIT System Design and Management Program are:
>System architecture, which focuses on artifacts themselves and includes concept, form, function and decomposition
>Systems engineering, which targets the processes that enable successful implementation of the architecture, and includes QFD, Pugh Concept Selection and Robust Design
>System and project management, which involves managing tasks to best utilize resources and employs tools such as CPM, DSM and System Dynamics

This article, the first in a series on the SDM core, introduces one aspect of the systems engineering 2007 summer course: industry case studies. These studies are chosen to show the applications of system engineering principles discussed in class. The Cummins Inc. case outlined below shows the type of creative and integrative system thinking that these studies highlight.


The challenge
Cummins Inc. is a global power leader comprising complementary business units that design, manufacture, distribute and service engines and related technologies, including fuel systems, controls, air handling, filtration, emission solutions and electrical power generation systems.

In this case, Cummins was challenged to develop a new turbocharged diesel engine for the heavy-duty Dodge Ram pickup truck. The engine had to be capable of meeting strict 2010 emissions standards in all 50 states. And, they had to work within the context of maintaining and building the Ram’s excellent reputation among Dodge’s diesel customers.

Improvements in power, torque, low levels of audible noise and imperceptible catalyst regeneration were also specified. These goals were to be attained while providing the same or better fuel economy as its current diesels while cutting emissions of nitrogen oxide (NOx) and particulate matter dramatically.

The approach
Cummins not only built on its longstanding expertise but also introduced a systems perspective into its development concepts.

The engineering team relied on Cummins’ intense interaction with the customer throughout the project to define and refine system requirements.

The team also developed a framework and architecture for the entire engine system. This allowed the engineers to develop the engine system concept and to identify significant suppliers for critical subsystem development.

To meet the 2007 emissions regulations, Cummins employed the following engine subsystems: cooled exhaust gas recirculation (used for the first time in a pickup); new air handling concepts, including a Cummins Variable Geometry Turbocharger; and a diesel oxidation catalyst, diesel particulate filter and a NOx trap for emissions control.

Understanding the interdependence of the various systems and subsystems, Cummins engineers worked hand in hand with the catalyst experts at supplier JMI to specify the wash coat for the catalyst and the NOx trap.

In addition, Cummins developed all of the algorithms and software needed to control the complex subsystems and their interfaces. This feature of their system development program led to a significant competitive advantage, which will be emphasized in the case study discussion.

The results
The new 6.7L turbo diesel system for the Dodge Ram pickup has enhanced combustion performance designed through simulation and modeling of combustion kinetics and injection pulse profiles. And, it utilizes a third-generation, high-pressure, 1,800 bar (26,000 psi) common rail fuel system from Bosch. This subsystem is capable of up to five injection pulses during a single combustion cycle in a cylinder.

Ultimately, Cummins was able to build a diesel engine considered the strongest, cleanest, quietest and best in class. The new Dodge Ram pickup engine is the first to satisfy the strict environmental requirements not only of 2007, but of 2010—three years ahead of its time.

Conclusion
As the Cummins case study shows, significant technical understanding is critical to the development of complex systems. Software development is also becoming an ever more important component of complex system design. In the end, deep technical understanding combined with evolving systems engineering competence has led to a product with significant competitive advantages.

This case study and others will be presented in full during this summer’s SDM course in systems engineering. If you would like to sample the course, please contact John M. Grace, SDM industry codirector, jmgrace@mit.edu, 617.253.2081. The course meets Tuesdays and Thursdays, 8:30-10:30 a.m. from June 12 to August 21, 2007.

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