Diesel consumption costs are currently among the three main expenses in heavy vehicle fleets in Brazil, strongly affecting the total cost of ownership (TCO - Total Cost of Ownership). This work aims to present a case study of a start-stop system tested in a vehicle and a dynamometer engine developed by a company in the mechanical metal sector in partnership with the university. After interviews conducted during the customer discovery phase for this system, was possible to validate fuel consumption as the main expense within large urban bus fleets. An urban bus equipped with a manual transmission and a turbocharger, a diesel cycle engine with 7.2 L of displacement, was defined as an object for a case study to prove the value proposition that the start-stop system about the fuel consumption e reduction. The urban bus would meet the limit of atmospheric emissions PROCONVE P7. The bus was subjected to tests in an urban cycle in the city of Curitiba under operating conditions in normal traffic. The results did present a reduction of 4,8% in diesel consumption, validating the hypotheses previously raised. The cycles ETC, WHTC, and urban performed on the vehicle were chosen for dynamometer tests. The engine was installed on the dynamometer without an after-treatment system and the results in the urban cycle present a reduction of 3,1% in CO2 emissions and 57,1% of particulate matter. The result of this study shows the importance of concurrent engineering in product development, enabling the development of prototypes in conjunction with customer discovery studies.