SwRI simulations show turbocharged Scuderi Engine could reduce a standard 2011 Nissan Sentra’s fuel consumption by up to 35% on FTP cycle
|Modelled results of fuel consumption in 2011 Nissan Sentra. Source: Scuderi. Click to enlarge.|
Scuderi Group, LLC released the top-level results of a vehicle computer study that it funded and that the Southwest Research Institute (SwRI) conducted, modelling various Scuderi Split-Cycle (SSC) engine designs, including the turbocharged, downsized air-hybrid version under consideration (earlier post), in a computer model of a 2011 Nissan Sentra.
The Sentra model was simulated through a standardized Federal Test Procedure-75 (FTP-75) drive cycle for each SSC engine design. Preliminary results showed up to a 25% decrease in fuel consumption (i.e., up to 33% increase in MPG) was achievable with an SSC engine replacing the Sentra’s engine when factoring in fuel cutoff during deceleration and idle in the model.
Results also showed that up to 35% decrease in fuel consumption (i.e., up to 54% increase in MPG) was achievable when compared to the model Nissan Sentra using a stock engine without fuel cutoff.
The primary purpose of the Study was to answer the fundamental question about fuel consumption. Scuderi Group commissioned SwRI to design and implement the computer Study, which could simulate an SSC engine in any vehicle of choice, driven through any drive cycle of choice. Results would then be compared to the same vehicle driven with its factory engine through the same drive cycle. The Nissan Sentra was the first vehicle chosen for the study, due to its competitive mileage and popularity.
At the onset of the study, a computer baseline model of the Sentra was established, which closely matched the measured performance of the actual 2011 Nissan Sentra. The lab mounted the Nissan Sentra on a chassis dynamometer and drove the vehicle through the FTP-75 drive cycle to generate the benchmark data.
Various SSC engine models were sized to match the acceleration and power of the Sentra’s conventional engine. Each Scuderi engine was then placed into the baseline Sentra vehicle and driven, via computer simulations, through the same FTP-75 drive cycle. Results were compared to the Sentra when operating with its conventional engine. The most favorable results were obtained using a preliminary model of the turbocharged SSC engine with a downsized compression cylinder configured to operate in air-hybrid modes.
The Scuderi Engine divides the four strokes of a combustion cycle between two paired cylinders—the left cylinder functions as an air compressor, handling intake and compression, while the right cylinder handles combustion and exhaust. With the compression cylinder separated from the power cylinder, the use of a standard turbocharger to convert recovered exhaust-gas energy into compressed air energy supports the downsizing of the compression cylinder to achieve substantial reductions in negative compression work.
Scuderi Group will provide more in-depth details on the results of the Nissan Sentra Study at the Engine Expo 2011 in Stuttgart, Germany, 17-19 May.