Combined air supply dual-fuel engine system with dual-needle valve fuel injector and combustion method

Abstract

The invention discloses a combined air supply dual-fuel engine system with a dual-needle valve fuel injector and a combustion method, and belongs to the field of combustion methods of dual-fuel engines. The combined air supply dual-fuel engine system comprises an air inlet channel, an intake valve, an exhaust channel, an exhaust valve, a divided manifold low-pressure injection natural gas injection valve, a high-pressure in-cylinder direct injection natural gas injection valve, a dual-needle valve fuel injector, an omega-shaped combustion chamber and the like. When the engine operates at low load and medium load, the high-pressure in-cylinder direct injection natural gas injection valve is controlled to perform single or multiple gas injections into the cylinder; when the engine operates at high load, a combined air supply mode of the air inlet outside the cylinder and the direct injection inside the cylinder is adopted, and different fuel oil and gas injection control strategies are adopted under different engine operating conditions. By controlling the natural gas injection quantity, the injection times and the injection time of the divided manifold low-pressure injection naturalgas injection valve and the high-pressure in-cylinder direct injection natural gas injection valve, the high-efficiency low-emission combustion of the engine in the full operating conditions range can be achieved, thereby improving the in-cylinder combustion, widening the load range of the engine, and reducing NOx emission effectively.

Description

technical field [0001] The invention belongs to the field of dual-fuel engine combustion methods, and in particular relates to a composite air-supply dual-fuel engine system with double needle valve injectors and a combustion method. Background technique [0002] With the shortage of fossil energy and increasingly stringent emission regulations, natural gas has developed into a potential diesel alternative fuel due to its high combustion efficiency, clean environmental protection, and good anti-knock performance. Compared with ignited natural gas engines, diesel ignited natural gas dual-fuel engines have better power performance, and the emissions can meet the requirements of international emission regulations. [0003] The dual-fuel engine is converted from a diesel engine, and the research on the combustion model of the dual-fuel engine is inseparable from the basis of the traditional engine combustion model. After blending natural gas, the law of heat release changes, so...

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Problems solved by technology

However, the mixing degree of direct injection natural gas and air in the cylinder is low, which makes the concentration of the mixture in the cylinder uneven and affects the combustion process in the cylinder.

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