RESEARCH OF FUEL SUPPLY PROCESSES IN GAS-DIESEL LOW-SPEED TWO-STROKE LOW-PRESSURE ENGINES

Abstract

The rise in prices for liquid petroleum fuels, observed over the past decades, as well as the tightening of environmental regulations on the content of marine engines of toxic substances and greenhouse gases in the exhaust gases, have made the use of natural and petroleum gases an attractive alternative to traditional motor fuels. And this is despite the additional technical difficulties associated with their use. Given that more than 70% of the main engines are in the merchant fleet, these are low-speed two-stroke engines, the solution of the problems associated with transferring them to gas fuel is particularly relevant at the present time. The problem of translation is aggravated by the fact that, due to the peculiarities of the organization of the workflow, in two-stroke engines of this class only internal mixing is possible, which is carried out during the compression stroke. The latter circumstance required the development of fundamentally different approaches to solving the problem in comparison with those traditionally used on four-stroke high and medium-speed engines. A certain limitation complicating the solution to the problem of organizing a working process on gas fuels is the need to keep the engine able to work on traditional liquid fuels in the entire range of load-speed modes. Currently, MAN and WinGD share leading positions in the field of dual-fuel low-speed engines, the first of which developed a line of engines with gas fuel supply to the engine working space under high pressure at the end of a compression stroke, and the second under low pressure at the beginning of a compression stroke . Each of these methods has both certain advantages and significant drawbacks. The low-pressure fuel supply greatly simplifies the design of the fuel system of the engine and reduces the requirements for ensuring its safety during operation, however, these engines are prone to detonation combustion, which significantly reduces their use, especially in near-nominal conditions. This article is devoted to the search and justification of technical solutions to minimize this drawback while maintaining the inherent advantages of the method.