Test Technologies Contributing to Electrification - 1. Test technologies that support the competitiveness of electric vehicles2.4 Test technologies for the digital phaseFig. 4 VDC HILS (Source: NISSAN TECHNICAL REVIEW No. 71)3. New Test Technologies Contributing to Electric Vehicle Development2.5 Measuring technologiesspecifications (usually done by parts suppliers), then system-level evaluation, and finally, vehicle-level evaluation. This allows for easy identification of causes and implementation of countermeasures in case the target is not achieved, ensuring the progress of development reliably.In the V-process diagram described above, it is depicted that progress should proceed smoothly along the V-shape without any backtracking. However, in actual development, if the evaluation results on the right side of the V-shape do not achieve the intended targets, iterations and backtracking occur. This means going through a feedback cycle of design -> prototype -> evaluation -> redesign -> prototype iteration -> evaluation iteration, which requires a corresponding amount of time and cost. Consequently, there is a need to perform preliminary assessments of the achievement level before creating actual physical prototypes. The phase before arranging the formal prototype vehicles is referred to as the digital phase, while the phase after the arrangement is called the physical phase. It is important during the digital phase to determine how to assess the performance achievement level of the prototype vehicles, as this helps reduce the need for design, prototyping, and evaluation iterations during the physical phase. So, how do we evaluate the performance when we don't have actual physical prototypes? This can be done by utilizing computer simulations or creating mock-ups that replicate certain parts of the vehicle. The technical challenge in the digital phase lies in deciding what and how to replicate based on the performance or system being evaluated.For instance, a traditional method for evaluating aerodynamic performance involves creating clay models that accurately replicate the vehicle's shape, allowing convenient shape modifications and trial and error evaluations. In recent years, there has been a trend towards faithfully reproducing structures within the engine compartment and under floor. However, these models only replicate the shape and do not have functioning engines or the ability to drive. The decision on what and to what extent to replicate is made by the test engineer.Lately, there has been an trend of Fig 4 illustrates an example of Hardware in the Loop Simulation (HILS) previously introduced in Nissan Technical Bulletin (No. 71, 2012). In this example, the increase in partial prototyping using 3D printers. This is particularly useful for pre-evaluating components with new structures or features that lack prior performance records. Although these prototypes may have lower strength, durability, or different surface finishes compared to actual parts, they provide the advantage of being physically evaluated for usability and other factors. Furthermore, there is a growing combining virtual evaluation environments and test pieces created through computer simulations with realistic mock-ups or advanced prototypes.entire brake hydraulic circuit, from the brake master cylinder to the VDC unit (ECU and actuator integrated), brake tubes/hoses, and brake unit, is reproduced in the real domain (actual device), while the remaining vehicle model is reproduced virtually (CAE) and combined.Determining what to replicate virtually and what to replicate in the real domain and how to combine them for evaluation is a crucial consideration.In discussing test technologies, another important element is measurement technology. To objectively and quantitatively capture vehicle performance, measurement is essential. Whether it is to reproduce and maintain the PG road surface, replicate the market environment on test benches, or recreate prototype vehicles based on design data, accurate measurement is necessary. To understand the mechanisms of phenomena and measure what needs to be known, the development of new measurement technologies is required. Additionally, in order to ensure the accuracy of test results, measurement accuracy assurance technology is crucial. This includes the establishment, implementation, and maintenance of facilities such as the Measurement Standard Center and the calibration equipment used within it. These responsibilities are also undertaken by engineers in the test department.In recent years, electric vehicle development has been progressing as a response to environmental issues such as global warming.When it comes to developing new vehicles using matured technological areas, development can proceed relatively the V-process using standardized know-how. However, when adopting new technologies, it is necessary to perform hypothesis verification through testing during the target setting and performance planning phases on the left side of the V-process. This allows for maximizing the value of the new technology and assessing the feasibility of its performance at an early stage to minimize backtrackings. This enables the development of high-value and competitive products for customers.smoothly along 35
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