Product Development i n t he World Auto Industry CHANGES in international competition in the past decade, and particularly the competitive problems of once-dominant U.S. firms and industries, have heightened interest in what causes international differences in productivity and product quality. Although analysis of macroeconomic data has produced some important insights, recent research has focused increasingly on the comparative behavior of industries, firms, and factories. 1 Such research raises in a direct way the issue of management efficiency. Especially at the factory level, a growing body of evidence This research was supported by the Division of Research, Graduate School of Business Administration, Harvard University. We are indebted to Brandt Goldstein and Frank Dubinskas for their assistance. 2. Notable discussions include David A. Garvin, "Quality on the Line," Harvard

Accurate evaluation of vehicles' transient total power requirement helps achieving further improvements in vehicle fuel efficiency. When operated, the air-conditioning (A/C) system is the largest auxiliary load on a vehicle, therefore accurate evaluation of the load it places on the vehicle's engine and/or energy storage system is especially important. Vehicle simulation models, such as "Autonomie", have been used by OEMs to evaluate vehicles' energy performance. However, the load from the A/C system on the engine or on the energy storage system has not always been modeled in sufficient detail. A transient A/C simulation tool incorporated into vehicle simulation models would also provide a tool for developing more efficient A/C systems through a thorough consideration of the transient A/C system performance. The dynamic system simulation software MATLAB/Simulink® is frequently used by vehicle controls engineers to develop new and more efficient vehicle energy system controls. A MATLAB/Simulink-based transient A/C system simulation model is easier to incorporate into MATLAB/Simulink-based vehicle simulation software; therefore, the availability of a transient A/C system simulation tool developed in the MATLAB/Simulink platform is important.NREL has recently developed an A/C simulation tool to address these needs. This paper describes in detail the modeling methods used for this new simulation tool. Comparison with measured data is provided to demonstrate the validity of the model. The agreement between simulation and measurement was shown to be good on both the component and system level. The capabilities of the model are also demonstrated by the example of simulating the SC03 cycle.

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275deuteration, as discussed below. dIoo (g/cm3) = ds4 + 0.0056 (f0.003) Table I shows the measurements of density as a function of temperature. The following function describes the density of the 94.1 %deuterated isobutyric add wltttin a standard deviation of 5 x loa g/cm3 ds4 (g/cm3) = 1.060866 -0.001117f + 1.4 X 10-'t2 Rerultswhere the temperature t is in degrees Celsius.By comparison with the density of hydrogenated, as opposed to deuterated, isobutyric acid (4, 5), the density of fully deuterated isobutyric acid is calculated to be Llterature Clted (1) Greer, S. C.; Moldover, M. R.; Hocken, R. Rev. Scl. Illinois 60674 2,4-Hexadiyne (or dbnethyldlacetylene, DMDA) was purified by room temperature ruMknatlon ( x = 0.9985) and Its vapor pressure measured at several tempefatures