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Two to the power of N = $ saved or spent

Since I began working in the realm of software systems for electrical interconnect design I have seen increased user choice in on-and off-road vehicles. I have read the technical papers and marvelled at the memorable phrase “combinatorial explosion” used to refer to the options a buyer of a high-end new passenger car is able to order.

Choice is good right? If you are fortunate enough to be able to walk into a car dealer and choose your new vehicle it is part of the customer satisfaction expectation, part of the manufacturer’s marketing tactics to be offering you one of six audio systems, 4-way or 6-way or 12 feature powered seats, ambient lighting located in door panels – Bluetooth plus infotainment trinkets in the instrument panel cluster. All dictate variations in the wiring loom located there and may influence content for antennae further to the rear of the car, not to mention those essential headrest DVD players. Children of previous generations never knew they were being badly treated by not having these and so had to invent other reasons their parents were being “so unfair” on long journeys.  That’s progress for you.

The end result of these choices being offered is an average of about 80lbs (36.25 kg) of wiring harness in every car. Average because there are variations. Many, many variations. Car makers and their suppliers route hundreds of signals for passenger and driver creature comforts using wires between microprocessors. There may be 25 of these in fairly moderately equipped Japanese/European and US passenger vehicles rising to a 70+ ECU count in luxury brands. A lot of customer choice is involved in this variation, needing a commitment to serious data management and modeling capabilities to control.  

The proliferation of variability in installations of approximately two and a half kilometers of wire per car (over one and a half miles) is expensive to manufacture and expensive to make with zero defects. An assembly plant for the car can only cope with so many derivative parts – storage area costs money, take-up of options is unsure – it becomes a multi-faceted logistical puzzle. Car companies and their suppliers are fighting a never ending battle to hold down costs and looking at ways not just to manage the design and manufacturing complexity (data, industrialization and logistics) cheaply, but also more recently to hold back the steep increase in numbers of microprocessors in the cars – to consolidate and integrate systems.  Toyota announced an ECU reduction initiative publicly in 2008.

 With truck manufacture there is often even more choice involved in ordering a new vehicle than in the family car – definitely so for those heavy trucks which transport everything modern society depends on. 

For transportation systems design and electrical interconnect engineers there is no escape – the complexity/variation problem is beyond human capacity to understand, you need assistance. This comes from software tools.

When you get extended functionality in the electrical interconnect design software – like CHS, you guard against introducing further complexity to deal with the (options) complexity. Essentially you are not de-skilling this part of the design activity and the challenges of managing changes within the complexity definitions of harness families. What software helps to do here instead is to extend the capabilities of experienced engineers, boosts their range and their reach and enables them to do more in less time. 

It is such a pivotal aspect of designing and engineering wiring in transportation systems I think that even a) advanced; b)robust;  c) stable and d) feature rich products like CHS Capital Integrator, Capital Desktop Architect and Virtual Architect are not aimed at replacing know-how and people they augment the vital human contributions.

Chrysler’s John Antilla at IESF Detroit in March presented a really insightful session about the challenges of complexity in the passenger car industry. One of his slides is pictured below (with his kind permission) and for me it was an “aha!” moment to see this on the screen  – a problem statement crisp and succinct.

Shown on John’s slide are increases in combinations/levels/complexity of the interconnect – see rows 2 and 3  – as a result of placing a new option (e.g. branch to a connector for a device) on either the Instrument Panel (I/P) or the body harness family. Which of the alternatives is going to be cheaper?

Effect of new branch and connector position on vehicle complexity

Effect of new branch and connector position on vehicle complexity

As John pointed out it is very difficult for an OEM to have insight into what marketing choices are driving the cost of harnesses’ complexity, it is very difficult for suppliers to know what tell OEM’s has contributed to the escalating cost of producing a multiplicity of derivatives.  

Can your data processing tell you from the many bills of material, can you infer what made your body harness now cost $3 more than the same harness four months ago?  Without sophisticated software tools, it is impossible to answer these questions or solve these problems forward or backwards in the design flow.

 You really must have good quality information technology assistance. Sink or swim. Spend or save. 

John Antilla, IESF, Virtual Architect, Capital Desktop Architect, Capital Integrator, Automotive Electrical and Electronic Systems Design, Wiring Harness, Complexity Management, Electrical Interconnect Design, Chrysler, CHS, CHS Capital Costing

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About Paul Johnston

Paul JohnstonI help Mentor Graphics customers to be successful, accomplish a more rapid return on investment. My professonal focus is on the Capital product line. I was born just outside of Manchester England, am now resident in the metro Detroit area of Michigan USA. Visit Paul Johnston's Blog

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