Trends—Spark Ignition

Abstract

Current and future combustion engine development targets a considerable reduction in fuel consumption and emissions to meet strict emission legislation despite steady or increasing customer comfort and performance demands. Additionally, reduced time to market is required despite increasing variations in customer demands and fuel qualities in worldwide markets. To meet these targets, gasoline engines have made progress in efficiency by the introduction of technologies such as direct injection in combination with downsizing and turbo‐ or supercharging, valve train variability, and a variety of additional measures to reduce friction losses such as electrification of accessories. In this article, current and future engine development trends are described and illustrated in detail. Potential future measures to further reduce fuel consumption are pointed out and evaluated. Besides well‐known mega trends such as downsizing and variable valve trains, concepts such as controlled autoignition, variable compression, and new ignition systems are considered. In general, the article shows the potential of new technologies to improve fuel consumption and emission behavior of future combustion engines.

Axial Flow Turbine Concept for Conventional and e-Turbocharging

“…A similar trend is observed in the location of the efficiency peak, which, for the axial type, is shifted to even lower Blade Speed Ratio (BSR) [9]. For the sake of completeness, it is worth mentioning that, in spite of the above-mentioned pros, radial turbines for automotive turbocharging size exhibit a higher efficiency peak, as well as a wider BSR area where these values are attained [9]. Early studies on axial-flow turbine turbochargers showed very promising results, such as those conducted by Honeywell on the "Dual Boost concept", in which a double sided compressor is coupled with an axial turbine [10].…”

“…Similar considerations to those concerning mixed-flow turbines swallowing capacity have led, only recently, to investigate the suitability of axial-flow turbines in turbocharging applications as well. In fact, at the same design mass flow rate, passing from radial to mixed-flow and to axial-turbines rotor inertia is progressively lowered [9]. A similar trend is observed in the location of the efficiency peak, which, for the axial type, is shifted to even lower Blade Speed Ratio (BSR) [9].…”

“…In fact, at the same design mass flow rate, passing from radial to mixed-flow and to axial-turbines rotor inertia is progressively lowered [9]. A similar trend is observed in the location of the efficiency peak, which, for the axial type, is shifted to even lower Blade Speed Ratio (BSR) [9]. For the sake of completeness, it is worth mentioning that, in spite of the above-mentioned pros, radial turbines for automotive turbocharging size exhibit a higher efficiency peak, as well as a wider BSR area where these values are attained [9].…”