Managing design and supply complexity in automotive electrical/electronic systems

Managing complexity: it’s not as tangible as a cable, connector, electrical center, or electronic module, but it is one of the critical services electrical/electronic (E/E) architecture suppliers like Delphi provides alongside these intricate components and systems. Without it, serious problems can result in terms of design, quality and delivery. With it, the right parts are manufactured and delivered for the right applications every time — on time and with the highest level of quality.

Managing complexity for an E/E architecture supplier like Delphi can be analyzed in two ways: managing the total number of part numbers/elements that comprise the overall E/E system, and managing the number of engineering changes that are required during both the vehicle development and the overall vehicle life cycle.

Managing the supply chain

Let’s look at the number of elements within a system first.

Previously, automotive engineers used older technologies such as mechanical and pneumatic controls to provide specific vehicle functionality. Many of these system designs required few electrical circuits. Over time, the cost of electronics has come down and engineers now use electrical/electronic controls to greatly enhance vehicle functionality in a number of ways: to reduce or eliminate emissions, to dramatically improve safety, and to provide greater levels of comfort and entertainment for vehicle occupants. This conversion from mechanical to electronic systems has significantly increased the number of elements within a vehicle’s E/E architecture.


Figure 1

Figure 1 provides an initial comparison of the relative complexity demanded of E/E architecture suppliers such as Delphi. It shows the number of electrical/electronic modules and finished wiring assemblies that are used today in one typical North American vehicle. The 32 electrical/electronic modules are provided by a number of different suppliers, since they are all subsystem specific and the customer can source specific subsystem components and modules independently of other subsystems.

For example, supplier A may provide the engine control and transmission control modules used to control emissions with the vehicle, while supplier B provides the radio, rear entertainment, and navigation modules. Other suppliers provide the brake control modules, the supplemental inflatable restraint modules, the body control modules, the electrical power distribution centers, and the door modules. The interface between all of these modules is managed by the automotive vehicle engineers via specified data bus protocols such as CAN or LIN.

In contrast, the 13 wiring harnesses used in this vehicle are provided by a single supplier. In this case, Delphi, since the electrical distribution system is treated by the customer as a single, crucial system. Most customers have concluded that overall wiring design complexity is best managed with a single supplier for a specific vehicle. Sometimes, two suppliers may provide the entire system, especially if a specific assembly, such as an engine harness, is shared across vehicle platforms.

But, this view of complexity doesn’t really tell the entire story about parts needed in the system. If we drill down one level lower than the finished good assemblies per vehicle level, we can see complexity in a different light. Figure 2 shows the number of components required to create the finished assemblies that are shipped to a single vehicle.


Figure 2

The 32 E/E modules shown in Figure 1 are comprised of 2,500 components. These components include the various sets of hardware parts and the software algorithms required for the modules to function as intended. For engineers responsible for designing electronic modules, managing complexity is focused on getting the software and hardware right. Managing this relationship is the critical task.

By comparison, the 13 wiring assemblies from Figure 1 are comprised of 6,500 components. For engineers who are responsible for designing wiring assemblies, managing complexity is focused on selecting the correct component part to provide the intended function at the required specification. Delphi needs to manage both the part numbers that comprise each wiring assembly (including connectors, terminals, grommets, seals, etc.) and also the internal relationships between these parts.

All of the above numbers represent just one specific vehicle within a vehicle platform that a particular customer might buy — maybe a truck with a V6 engine, a rear entertainment system, dual-zone air conditioning, real-time dampening, driver memory seat, heated seats, a short bed cab, trailer capability, and four doors.

In reality, most automotive suppliers have a family of vehicles within a vehicle platform and offer a variety of equipment options at different price levels. All of this drives additional complexity for suppliers of E/E architecture. Figure 3 shows how much variation and complexity occurs as the vehicle manufacturer offers the entire range of subsystems and options within a vehicle platform.


Figure 3

In this view, the original 32 E/E modules found in the one vehicle example in Figure 1 need to expand to 350 module part numbers to account for all of the variations required for this specific vehicle platform. Sometimes, the difference in part numbers for a specific E/E module will be driven by changes in software that are required, as well as different component use within a module.

Powertrain modules may have 20 to 25 part numbers required for various engine options and/or emission requirements in different locations (states, countries, etc.) Electrical centers may require 25 to 30 part numbers per center to meet the requirements across vehicles. Other modules such as brake, navigation, or HVAC modules may need only one or two part numbers to meet the requirements for all vehicles sold within a single vehicle platform. On average, the 32 modules require slightly more than 10 part numbers each to cover all the variations needed across a vehicle platform.

When we look at the original 13 wiring assembly part numbers in Figure 1, we see a significant number of assembly parts (4,250) required to meet all of the vehicles that might be sold by a vehicle manufacturer. Unique wiring harness part numbers are required for every combination of circuits and components that are needed for specific vehicle builds. Styling differences across vehicle trim levels may change the number and placement of lights and switches, and this will drive the need for different wiring assembly part numbers. Any subsystem mechanization changes for additional functionality in up level options always require additional wiring assembly part numbers.

For truck platforms, differences in bed lengths, number of doors, etc., will also mean managing more assembly part numbers. The differences in one part to another may be minor, but different part numbers are used to ensure the right assembly is used in the right vehicle that is ordered. In this vehicle platform example, the customer requires over 1,000 instrument panel wiring harness part numbers, and over 1,000 body wiring harness part numbers to address all the vehicle combinations within the platform. On average, the original 13 wiring harnesses require over 300 part numbers each to cover all the variations needed across a vehicle platform.

Like any supplier, Delphi is expected to manage all of the part numbers within its products and systems — both finished assemblies and internal components. The above three graphs are for only one customer vehicle platform in production today. When you consider that Delphi provides products and systems for hundreds of vehicle platforms and is developing new E/E architectures for future years, the level of complexity management required across the entire global organization can boggle the mind. Today, for Delphi, that means managing nearly 2 million part numbers related to E/E architecture alone.

Management tools

At Delphi, our Global Shared Database is the go-to tool for managing E/E architecture complexity and is one of the capabilities of our Velocity Tool Suite, a comprehensive portfolio of integrated design, analysis and simulation tools.

For over ten years, Delphi has had this Global Shared Database in place and we are continuing to improve it all the time. The database does so much more than simply share data. It is the single most important tool we have for managing complexity. This global database system manages more than 500 connector/terminal relationships, 30 different component categories such as cables, connectors, terminals, locks, seals, etc., and 6,200 component attributes for characteristics like color, size of cavity or wattage of a light bulb.

The tool can import customer data from any format given to us, convert that to a common format that our entire global engineering team can use to design, draft, and document changes to the system and deliver the build documentation to manufacturing in the same format every time. This includes the drawing, bill of material, bill of labor, and any other information required to schedule and coordinate the manufacturing plants involved in production. Once that is completed, we can translate the data back to the customer’s preferred data format and send it to them electronically for their review, approval, and subsequent storage in their internal information technology systems.

Any supplier’s engineering, production control, logistics, and manufacturing organizations need to manage the acquisition, scheduling, and delivery of all of the parts they use every day. Delphi uses the SAP system to globally manage our enterprise operations — order receiving, manufacturing scheduling, customer invoicing, financial accounting, etc. Delphi has developed the necessary system interfaces to electronically exchange real-time information from our engineering-based Global Shared Database system to our enterprise based SAP system. These major systems and their critical interfaces are now deployed and used in Delphi facilities throughout the world.

Dealing with engineering changes

Let’s look at one last way to view managing complexity for an E/E architecture supplier — dealing with engineering changes to the product.

With regards to managing complexity from an engineering change viewpoint, Delphi, as a global supplier, implements over 3,000 engineering changes per month. These are just the changes that make it to production. Many more are proposed and evaluated, but never make it to the manufacturing floor. In order for the automotive supplier to process these change requests quickly and seamlessly, the operating systems and information technology tools must be able to dependably provide the real-time data that is needed and used throughout the global enterprise. Complexity management refers to having these tools at the ready and the expertise to know how to use them every hour of every day.

Since the electrical/electronic distribution system impacts all vehicle systems and designs are initiated early in the vehicle development process, they have long been associated with complexity from a change perspective. A complete E/E architecture system can undergo thousands of changes over a product life cycle.

In comparison, a typical heating, ventilation and air conditioning module may go through only five design changes over its entire lifetime. Every single change is an opportunity for error. With all of the variables and relationships between components, it’s easy to see how a change to a single part can have a major ripple effect. That is why every wiring harness we design goes through more than 500 computer-aided design (CAD) checks and over 200 database design checks against defined rules and specifications before it is released into production. This is another key function that we have integrated into our Global Shared Database system.

Let’s take the wiring harness as an example. Vehicle manufacturers make design and data changes that impact the wiring harness all the time. It’s the nature of the business. Wiring is flexible, and there are a number of different positions and paths it can take inside the vehicle.

Other parts are stationary and must remain in a fixed location. Moving the placement of devices in the vehicle, changing component specifications or suppliers of other electrical/electronic devices, or adding new electrical/electronic content are just a few examples of the types of changes that impact a wiring harness and the overall E/E architecture of a vehicle.

Sometimes a change can be made to something seemingly unrelated to the vehicle electrical system or the wiring harness that can impact where the wiring can be placed within the vehicle. These changes come at a fast and furious pace, with most customers requiring new designs and new price commitments within 10 days of submitting a change request.

A new Manufacturing Analysis project we are working on will soon allow us to report back to the customer on the impact a change has on any potential wiring design problems, the impact on additional tooling or equipment investment that would be needed, and even on how the proposed change would impact the number of people needed for manufacturing. After considering all of these factors, we will be able to advise the customer as to whether the proposed change is indeed the best solution for them.

For the E/E architecture supplier, managing inventory is a final important part of this complex balancing act. With thousands of part numbers, and multiple engineering change revisions in the pipeline at any given time (some that are implemented and some that are not), both Delphi and the end-use customer need to assess the impact a change will have on our inventories. If we don’t use up existing inventory, parts can become obsolete and essentially worthless. Thus, all changes need to be coordinated to avoid any excess inventory, both within the wiring manufacturer’s facilities, but also within the vehicle manufacturer’s facilities.

Vehicles are amazingly complex. Most have more than one mile of wiring, dozens of computer modules and multiple serial data links. A vehicle’s E/E architecture must support powertrain, entertainment, occupant protection and other vital vehicle systems. No longer does a vehicle electronic system control just one or two accessories. As vehicles have become equipped with more electronically-driven features like navigation and infotainment systems, airbags, multi-zone climate control and power closures, the development of E/E architecture continues to take a more predominant role in vehicle design.

You can’t package it up and ship it to the customer, but you can put a price on complexity management. The cost to the customer for not considering a supplier’s ability to manage complexity is great, and can lead to serious damage to their bottom line.