By Donald Parker, PE, CVS-Life, FSAVE
Each year the Miles Foundation provides a $250 award for the best paper submitted to the annual conference that portrays function inspired change. This award is in honor of Larry Miles who brought us function analysis as a deliberate way to improve value.
After reviewing some 61 papers submitted this year, the winning paper was by P. Arjunraj, for a value study on the Intake Manifold in Automotive Engines. He is the Senior Engineer for the Engine Research & Development of India’s Mahindra and Mahindra Limited.
The primary function of the intake manifold is “guide flow” of air to evenly distribute the combustion mixture (or just air in a direct injection engine) to each intake port in the cylinder head(s). Even distribution is important to optimize the efficiency and performance of the engine.
The paper documents the orientation phase conducted to make all employees aware of the company-wide initiative for Value Analysis, Quality Improvement & Sustainability. The workshop was conducted by a cross functional team from design, development, testing, purchase, sourcing, marketing, quality, and production.
The paper discusses 27 function of the three major components of the system studies: the intake manifold, its air duct and its water outlet piping. It also discusses the 12 functions for its three methods of connection: inserts and bolts, o-rings and gaskets, and welded joints.
The paper shows the FAST diagram created by the team and the Function-Cost-Worth assessment of all of the components. This led them to study just three of the functions which contributed to 82% of the cost. They developed creative ideas and used paired comparison and decision matrix analysis to separate out the best ideas for further study.
Function analysis resulted in substituting a plastic designed manifold, as shown below, for the previously used aluminum manifold resulting in significant cost savings and weight reduction with no significant effect on engine performance, durability or maintainability.
What is so significant about this change is that the team, during the development phase, defined the various tests that were needed to be carried out to ensure the performance, durability and reliability of the components. Separate validations were done with respect to individual components as well as entire engine system as a whole. The vibration measurement and other durability tests such as cyclic load test, rated power test and high speed test were carried out as a part of design verification plan for the proposed plastic intake air manifold system. There were no failures encountered during validation. The vibration measurement was done between existing layout and modified layouts. FEA Analysis was carried out to find the stress and deflection acting on plastic material (Poly Amide). The development of plastic intake manifold was initiated based on the analysis that was been done with the help of ANSYS software.
| Sl. No | Test included in Development | Targeted Durability hours |
| 1 | High Speed Test | 150 |
| 2 | Rated Power Test | 400 |
| 3 | Cyclic Load Test | 1000 |
| 4 | Resonance Durability Test | 500 |
| 5 | Thermal Shock Test | 400 |
| 6 | Composite Durability test (CDT) | 1 Lakh Kilometers |
| 7 | Accelerated Durability Test (ADT) | 100 Cycles |
| 8 | General Highway Durability (GHD) | 50,000 Kilometers |
After successful testing, the drawings for the plastic intake air manifold were finalized during the implementation phase and purchase order was done. In this phase the work order and sales order are issued after getting customer approval for the change. The PPAP (Part Production Approval Process), PSW (Part Service Warranty) was done during this phase. The implementation was done as per the timeline projected at the start of the project.
The plastic air intake manifold (PAIM) has been adopted into passenger car diesel engines as standard equipment. The advantages of the PAIM are light mass weight, low cost, high thermal-insulation efficiency and reduction of air pressure loss compared with a metal aluminum air intake manifold. Plastic intake manifold is made to improve the smoothness of the port interior surface and reduce the weight and cost of the intake manifold. There is a cost reduction of 40 percent as compared to using aluminum manifolds. Thus the value of the component is improved by reducing the cost of the engine without affecting the performance of the engine.
In addition, there is a fuel benefit of 0.1% improvement in fuel consumption. Hence the value is improved with increase in function and by reducing cost without compromise on quality, reliability and performance.
This was truly a function inspired change.
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