Method for injecting fuel into the combustion chambers of an air-compressing, self-igniting internal combustion engine
First Claim
1. A fuel injection system for air-compressing, self-igniting internal combustion engines, comprising a high-pressure fuel reservoir (1) constantly supplied by a high-pressure pump (2, 2'"'"'), electrically controlled fuel injection valves (5, 5'"'"', 5") connected to the high-pressure fuel reservoir, said control valves are controlled by an electric control unit, the pressure of the high-pressure fuel reservoir is monitored by a pressure sensor (7), control signals from said pressure sensor (7) are received by the control unit (8), and depending upon the result of comparison with set-point values that are stored in a performance graph (9), an intervention into control elements (11, 12, 14) used for setting the pressure of the high-pressure fuel reservoir (1) is made by the control unit;
- that furthermore as a function of crankshaft angles specified in the performance graph, the injection onset and the end of the main injection and additionally the injection onset and end of a postinjection is controlled by the control unit, and as a function of operating parameters as well as a desired torque output by the engine, the main injection quantity and, corresponding to this quantity and to parameters defined in the performance graph, the onset and quantity of the postinjection are controlled.
1 Assignment
0 Petitions
Accused Products
Abstract
A method and apparatus for injecting fuel into combustion chambers of an internal combustion engine, in which the total injection quantity for the engine is split into a main injection quantity and a small postinjection quantity, the latter being closely coupled to the end of the main injection quantity and being injected with the same fuel pressure as the main injection quantity. This reduces soot emissions at otherwise identical engine operating parameters. Because of the interaction among soot emissions, NOx emissions and specific consumption, the postinjection, while soot and NOx emissions are kept the same, can also be employed to lower the specific consumption of the engine.
25 Citations
20 Claims
-
1. A fuel injection system for air-compressing, self-igniting internal combustion engines, comprising a high-pressure fuel reservoir (1) constantly supplied by a high-pressure pump (2, 2'"'"'), electrically controlled fuel injection valves (5, 5'"'"', 5") connected to the high-pressure fuel reservoir, said control valves are controlled by an electric control unit, the pressure of the high-pressure fuel reservoir is monitored by a pressure sensor (7), control signals from said pressure sensor (7) are received by the control unit (8), and depending upon the result of comparison with set-point values that are stored in a performance graph (9), an intervention into control elements (11, 12, 14) used for setting the pressure of the high-pressure fuel reservoir (1) is made by the control unit;
- that furthermore as a function of crankshaft angles specified in the performance graph, the injection onset and the end of the main injection and additionally the injection onset and end of a postinjection is controlled by the control unit, and as a function of operating parameters as well as a desired torque output by the engine, the main injection quantity and, corresponding to this quantity and to parameters defined in the performance graph, the onset and quantity of the postinjection are controlled.
- View Dependent Claims (9, 10, 11)
- 2. A method for injecting fuel into combustion chambers of an air-compressing, self-igniting internal combustion engine, which comprises injecting a quantity of fuel by means of a main injection into a combustion chamber, after said main injection, injecting fuel via a post injection into the same combustion chamber of the engine, providing a high pressure pump feeding permanently fuel under high pressure into a high pressure fuel reservoir which is connected with at least one electrically controlled injection valve by which said main injection as well as the post injection is injected, providing means to insure that the injection pressure of the main injection and the post injection are the same, electrically controlling the opening and closing events of said injection valve for metering said main and post injection quantities of fuel, and effecting the opening event of the injection valve for the post injection after the closing event of said injection valve for termination of the main injection.
Specification