What are the barriers against brake thermal efficiency beyond 55% for HD diesel engines? New Ace Inst. Company, Limited

Format:

Book

Conference/Event

Author/Creator:

Watanabe, Kazumasa, author.

Contributor:

Kawaharazuka, Fumihiro

Uchida, Noboru

Yokogawa, Kazuhiro

Conference Name:

15th International Conference on Engines & Vehicles (2021-09-12 : Capri, Italy)

Language:

English

Physical Description:

1 online resource cm

Place of Publication:

Warrendale, PA SAE International 2021

Summary:

Thermal efficiency improvement in heavy-duty (HD) diesel engines has been an essential and endless challenge even assuming the long-term full utilization of carbon neutral fuels, since the supply amount of such fuels should be far less than the global demand for the ever-increasing diesel engines. State of the art production HD engines already achieve about 50% brake thermal efficiency even without any waste heat recovery systems. However, they can merely reduce about 8% of fuel consumption or CO2 emissions from the current state, which could not be enough for the engineering target in the next decade. This study focuses on the technology integration to aim beyond 60% indicated thermal efficiency (ITE) with a single-cylinder HD diesel engine as an alternative to achieve 55% brake thermal efficiency (BTE) with multiple-cylinder engines. The proposed compression ratio (28:1), excess air ratio and new ideal thermodynamic cycle were determined by a simple cycle calculation. The barriers for further ITE improvement are mainly laid in both cooling loss reduction and fuel-air mixture formation improvement under very high temperature and density in-cylinder conditions with high compression ratio (small cavity volume). For the significant cooling loss reduction, a new concept of in-cylinder wall surface coating combined with intake chilling was experimentally investigated based on the hypothesis of the cooling loss mechanism which relates the heat transfer phenomena on the surface not only during combustion period but also during exhaust and intake strokes. For the mixture formation improvement, several numerical or experimental case studies were carried out to find the guideline for the chamber shape and fuel injection equipment design. Although the engine has not been optimized yet, 59.5% ITE was experimentally achieved with the engine by means of the multiple-injector concept (ref. SAE 2016-01-0729) as a tentative result

Notes:

Vendor supplied data

Publisher Number:

2021-24-0039

Access Restriction:

Restricted for use by site license