Search Results

Cold spray (CS) is a rapidly developing solid-state repair and coating process, wherein metal deposition is produced without significant heating or melting of metal powder. Solid state bonding of powder particles is produced by impact of high-velocity powder particles on a substrate. In CS process, metal powder particles typically of Aluminum or Copper are suspended in light weight carrier gas medium. Here high pressure and high temperature carrier gas is expanded through a converging-diverging nozzle to generate supersonic gas velocity at nozzle exit. The CS process typically uses Helium as the carrier gas due to its low molecular weight, but Helium gas is quite expensive. This warrants a need to explore alternate carrier gases to make the CS repair process more economical. Researchers are exploring another viable option of using pure Nitrogen as a carrier gas due to its significant cost benefits over Helium.

Emission, fuel economy and productivity in non-road mobile machinery (NRMM) depend largely on drive cycles. Understanding drive cycles can provide the in-depth information and knowledge that help the system integrator better optimize the vehicle management system. Some non-road engine test cycles already exist nowadays. However, these cycles are mainly for engine emission regulation purpose, and not closely tied to real world applications. Therefore, from both industries and academia, it has been the common practice to instrument and retrofit a vehicle, assign a professional driver operate the retrofitted vehicle for real testing, and compare the results to the baseline vehicle under the similar operating conditions. Obviously this approach is time consuming and resource intensive. In this paper, we attempt to address this issue by introducing a method of constructing standard drive cycles from in-field operation data.

Simulations used to estimate carbon dioxide (CO2) emissions and fuel consumption of medium- and heavy-duty vehicles over prescribed drive cycles often employ engine fuel maps consisting of engine measurements at numerous steady-state operating conditions. However, simulating the engine in this way has limitations as engine controls become more complex, particularly when attempting to use steady-state measurements to represent transient operation. This paper explores an alternative approach to vehicle simulation that uses a “cycle average” engine map rather than a steady state engine fuel map. The map contains engine CO2 values measured on an engine dynamometer on cycles derived from vehicle drive cycles for a range of generic vehicles. A similar cycle average mapping approach is developed for a powertrain (engine and transmission) in order to show the specific CO2 improvements due to powertrain optimization that would not be recognized in other approaches.