Wire-harness-design software from Linius

There are numerous reasons why the design of electromechanical systems is complex, including the number of wires, cables, connectors, shielding, and other components that comprise a system. Additionally, space constraints, environmental concerns, interference from other electrical systems, and manufacturing requirements further complicate the process. Most companies verify the form, fit, and function of the hardness by building prototypes. Linius Technologies, Inc. offers a family of software tools, EMbassy v3.0, that combine electrical and mechanical CAD principles to automate the harness-design process.

The EMDesigner toolset of Linius Technologies' EMbassy v3.0 is a 3-D editor that enables the user to place connectors, define a harness as a series of channels, and route wires into channels in real time.

Rather than replacing or displacing tools, EMbassy complements current design methodologies and integrates easily into existing design and manufacturing environments. The new version provides customer-driven enhancements that enable electromechanical engineers to design and document virtual wire-harness and cable systems using a 3-D model. Key innovations include performance boosts for large assemblies, a write-API enabling end-user customization, and support for rectangular wire bundles or channel cross sections.

"Continual communication with our user base informed us that larger and larger assemblies were being tackled by our users, so we focused on increasing performance in that area," said Tim Alibozek, Linius Technologies President. "With v3.0, we've accomplished major enhancements in that and other areas."

With the additional capability to display wire bundles as rectangular cross sections, EMbassy v3.0 provides a realistic 3-D depiction of all types of harness and cable cross sections. In addition to controlling the default channel size and surface offset, the user can specify a rectangular cross section and choose from a variety of packing algorithms. Precise control of the rectangular channel shape is provided by an enhanced manipulator that controls both control point location and orientation.

Wire harnesses are either contained in single subassemblies or spread throughout an entire large system. With these large systems, maximum performance is critical since large amounts of detailed information are required to specify fully a wire harness. VRML-based viewing technology provides improved large assembly viewing with new enhancements added to the software to maximize system performance further, such as a show/hide functionality that has been expanded to include all EMbassy objects. Wires can be viewed as lines, removing the overhead of the actual diameter sweeps. The complexity of circular objects can be controlled globally. Also, according to the company, file opening times have been improved by 25%.

EMNailboard creates a flat 2-D one-to-one manufacturing drawing of the harness, taking into account the position and curvature of the harness in the 3-D model.

EMbassy v3.0 expands on the currently available read-API that is used to create configurable design-rule checks by offering a write-API. Users can now programmatically add and modify objects and create custom functions to meet their process requirements.

The software automates the wire-harness-design processes by taking a 3-D model from a CAD package such as Solid Edge, Pro/ENGINEER, or SDRC and net-list information from a schematic or a from/to list. Using these data as a basis, the user defines harness paths in the 3-D model, routes wires, and performs design rule checks. Following the 3-D design, the software produces 2-D nailboard and specification drawings, wire run lists, and bills of materials. An IGES model is exported and read into the CAD modeler to complete the design.

EMbassy creates a virtual prototype of a harness within a 3-D model and enables the prototype harness to be ready for installation into the machine at an earlier stage in the manufacturing process. Other advantages are the automatic calculation of wire lengths and bundle diameters and the creation of a complete bill of material. The harness-design process traditionally required taking measurements of the prototype machine with a tape measure, manually adding up lengths of wire, and counting components for the bill of materials. This process often introduced human error, resulting in corrections that had to be made late in the design process.

SwRI launches Tier 3 consortium

Southwest Research Institute (SwRI) has launched the Naturally Aspirated Tier 3 (NAT3) consortium to develop technological solutions for off-highway, naturally aspirated diesel engines. The research consortium was created to achieve the adopted and expected U.S. Environmental Protection Agency (EPA) Tier 3 emissions levels set to go into effect in 2008 for 37-75 kW (50-100 hp) engines.

According to SwRI, the off-highway-engine industry faces special problems meeting the proposed Tier 3 standards because naturally aspirated diesel engines play a predominant role in many off-highway markets, including vehicles such as forklifts, tractors, and front-end loaders. Tier 3 compliance is significantly more difficult for these smaller, naturally aspirated diesel engines than for more expensive turbocharged and intercooled diesel engines. Through NAT3, off-highway engine, vehicle, and equipment manufacturers will investigate pre-competitive technologies aimed at helping diesel engines of less than 75-kW (100-hp) power levels achieve Tier 3 standards.

Technical goals of NAT3 are to determine technology to achieve and demonstrate compliance with:

• Oxides of nitrogen (NOx) plus non-methane hydrocarbon (NMHC) levels of 4.23 g/kW•h (0.007 lb/hp•h).
• Particulate matter levels of 0.12 g/kW•h (0.0002 lb/hp•h).
• Carbon monoxide levels of 3.15 g/kW•h (0.005 lb/hp•h).

These goals address EPA concerns as well as anticipated future European and Japanese emissions regulations. The emissions goals have an allowance of 10% for deterioration factors and manufacturing variability. NAT3 will try to achieve the emissions goals with fuel economy, carbon dioxide (CO2), and specific engine power levels comparable to Tier 2-compliant, naturally aspirated engines.

Three technical projects are proposed to begin the NAT3 program: direct injection, indirect injection, and homogeneous charge combustion ignition configurations. NAT3 is a three-year research program with a yearly renewable contract.

The advantage of a consortium for a member company is that the yearly contribution is leveraged 15 to 25 times, depending upon the number of participants, to provide substantially more research than would be possible by funding from a single member, according to SwRI. The institute expects 15 to 25 members to participate in NAT3 and has introduced the program to European, Asian, and U.S. companies.