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Designing for human variability (DfHV) requires efficient allocation of sizing and adjustability. This can preserve product performance while reducing some measures of cost. For example, specifying only as much adjustability as necessary for a desired level of accommodation leads to devices which are better suited to their users and more cost efficient. Similarly, when multiple sizes of an adjustable artifact are to be produced, specifying only as many sizes as are necessary, with an appropriate amount of adjustability per size, leads to a set of products that cost less, require fewer unique parts, facilitate maintenance standardization, and ease inventory control. An alternative to the standard procedure of evenly dividing size ranges is considered wherein an equal degree of accommodation per size is also presented. A simple example related to exercise bicycle seat height is discussed.

Two widely available engine and hybrid electric vehicle (HEV) simulation packages have been integrated to reduce fuel consumption and pollutant emissions for a hybrid electric sport utility vehicle. WAVE, a one-dimensional engine analysis tool available from Ricardo Software, was used to model a 2.5L 103 kW Detroit Diesel engine. This model was validated against engine performance and emissions data obtained from testing in a combustion laboratory. ADVISOR, an HEV simulation software developed by the National Renewable Energy Laboratory in partnership with the Department of Energy (DOE), was used to model a 2002 Ford Explorer that is being converted into an HEV by the Penn State University FutureTruck team. By integrating the output file from WAVE as the input engine data file for ADVISOR, one can predict the effect of changes in engine parameters on vehicle emissions, fuel consumption, and power requirements for specified drive cycles.

Two of the goals of the Penn State FutureTruck project were to reduce the emissions of the hybrid electric Ford Explorer to ULEV or lower, and improve the fuel economy by 25% over the stock vehicle. The hybrid electric vehicle system is powered with a 103kW 2.5L Detroit Diesel engine which operates with a fuel blend consisting of ultra-low-sulfur diesel and biodiesel (35%). Lower emissions are inherently achieved by the use of biodiesel. Additionally, the engine was fitted with a series of aftertreatment devices in an effort to achieve the low emissions standards. Vehicle testing has shown a gasoline-equivalent fuel economy improvement of approximately 22%, a reduction in greenhouse gas emissions by approximately 38%, and meeting or exceeding stock emissions numbers in all other categories through the use of an advanced catalyst and control strategy.