Zero-dimensional/one-dimensional computational fluid dynamics codes are used to simulate the performance of complete internal combustion engines. In such codes, the operation of a turbocharger compressor is usually addressed employing its performance map. However, simulation of engine transients may drive the compressor to work at operating conditions outside the region provided by the manufacturer map. Therefore, a method is required to extrapolate the performance map to extended off-design conditions. This work examines several extrapolating methods at the different off-design regions, namely, low-pressure ratio zone, low-speed zone and high-speed zone. The accuracy of the methods is assessed with the aid of compressor extreme off-design measurements. In this way, the best method is selected for each region and the manufacturer map is used in design conditions, resulting in a zonal extrapolating approach aiming to preserve accuracy. The transitions between extrapolated zones are corrected, avoiding discontinuities and instabilities.

This paper deals with the transient response of a highly turbocharged gasoline engine. This downsized engine should behave as a naturally aspirated engine when the throttle is suddenly opened. However, a turbo lag occurs and this phenomenon is of large importance for the vehicle acceleration and driver sensations. To reduce turbo lag effects, an electrical compressor (E-booster) was used to improve the main compressor and engine responses. The study was led on a three cylinder 1L turbo-charged engine. 1-D simulations (WAVE code) with a MATLAB-SIMULINK coupling were used to calculate the engine and vehicle transient responses. The vehicle, turbocharger and E-booster characteristics were simulated by the model. Second to third gear wide open throttle accelerations, varying engine loads at constant speed were also simulated. The calculations give important results like E-booster electrical consumption, and focus on the most significant parameters. By increasing the mass flow in the main compressor, the electrical booster largely improves the engine response. Large gains were obtained during the acceleration: the electrical booster reduces the response time from 3s to 1s.

Hydrogen internal combustion engines (ICEs) have gained significant attention as a promising solution for achieving zero-carbon emissions in the transportation sector. This study investigates the conversion of a 2 L Diesel ICE into a lean hydrogen-powered ICE, focusing on key challenges such as hydrogen mixing, pre-ignition, combustion flame development, and NOx emissions. The novelty of this research lies in the specific modifications made to optimize engine performance and reduce emissions while utilizing the existing Diesel engine infrastructure. The study identifies several important design changes for the successful conversion of a Diesel engine to hydrogen, including the following: Intake port design: transitioning from a swirl to a tumble design to enhance hydrogen mixing; Injection and spark plug configuration: using a lateral injection system combined with a central spark plug to improve combustion; Piston design: employing a lenticular piston shape with adaptable depth to enhance mixing; Mitigating Coanda effect: preventing hydrogen issues at the spark plug using deflectors or caps; and Head design: maintaining a flat head design for efficient mixing, while ensuring adequate cooling to avoid pre-ignition. These findings highlight the importance of specific modifications for converting Diesel engines to hydrogen, providing a solid foundation for further research in hydrogen-powered ICEs, which could contribute to carbon emission reduction and a more sustainable energy transition.