Method for pilot injection of fuel in diesel engines
AssigneeAB Volvo
InventorHeinz E. A. Holmer
Life of this patent
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Abstract
A method for the pilot injection of fuel in a direct injection diesel engine with a depression in the tops of the pistons. The pilot fuel, of relatively high cetane number, e.g. diesel fuel, is sprayed prior to the main spray, obliquely from the side into the piston depression in a direction counter to the rotation of the intake air. Thereafter, during the same combustion cycle, the main spray, of lower cetane number, e.g. methanol, is sprayed in a zone around the center axis of the piston depression. A substantial reduction in pollutants is achieved.
Claims11
In a fuel injection method for direct injection diesel engines with a depression in the tops of the pistons, in which a first injection pump with a regulator and accompanying first injector for each cylinder sprays fuel with a relatively low cetane number in a main spray in a zone around the center axis of the respective piston depression;
- the improvement comprising injecting a pilot spray of a fuel with a relatively high cetane number from a second injection pump (6) with a regulator and accompanying second injectors (8) for each cylinder, from the side into the respective piston depression in a direction (B) toward a central zone in the piston depression in which the intake air rotates, operating both of said injection pumps during a combustion cycle, and injecting said pilot spray before said main spray so that the compression combustion of the fuel from the second injection pump (6) can initiate the combustion of the fuel from the first pump (1).
Dependencies are inferred from the claim text.