Fuel injection device for an internal combustion engine having preinjection and main injection air compression and self-ignition
AssigneeDaimler-Benz Aktiengesellschaft
InventorsUlrich Letsche, Gunther Hafner, Karl-Ernst Noreikat
Life of this patent
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Abstract
The invention relates to a fuel injection device for an air-compressing fuel-injected internal combustion engine, which has an injection line leading from a pump element of high pressure injection pump to a bifurcation branch leading to a main injection nozzle and a preinjection nozzle. A nozzle needle of the preinjection nozzle opens counter to the direction of flow of the fuel and has a body designed with a stepped piston which, in the case of a closure initiating fuel pressure lying above an opening fuel pressure of the nozzle needle, moves the nozzle into a position to end preinjection.
Claims20
Fuel injection device for an air compression and self-ignition internal combustion engine having preinjection and main injection, comprising:
- a high pressure multi-pump element injection pump with an injection line leading from each pump element to a line bifurcation which is continuously connected to a main injection nozzle and to a feed bore of a preinjection nozzle;
- the preinjection nozzle having a nozzle needle moveably guided in a nozzle body;
- the nozzle needle being lifted off a value seat against the force of a restoring spring in response to fuel pressure of the fuel pump in the feed bore and counter to a direction of flow of fuel in the feed bore;
- wherein the preinjection nozzle has a body in which a stepped piston is longitudinally displaceable;
- the stepped piston is biased onto a sealing seat by spring force from the prestoring spring and is connected to the feed bore by a connecting channel;
- and
- wherein fuel pressure from the fuel injection pump in the feed bore is controlled by the high pressure injection pump to reach a closure initiating pressure in the feed bore which is above an opening pressure and which causes the stepped piston to open and move the nozzle needle into a closed position to end preinjection and to maintain the needle in said closed position until fuel pressure from the injection pump drops to a value allowing the stepped piston to close.
Fuel injection device for an air compression and self-ignition internal combustion engine having preinjection and main injection, comprising:
- a high pressure multi-pump element injection pump with an injection line leading from each pump element to a line bifurcation which is connected to a main injection nozzle and to a feed bore of a preinjection nozzle;
- the preinjection nozzle having a nozzle needle moveably guided in a nozzle body;
- the nozzle needle being lifted off a value seat against the force of a restoring spring in response to fuel pressure in the feed bore and counter to a direction of flow of fuel in the feed bore;
- wherein the preinjection nozzle has a body in which a stepped piston is longitudinally displaceable;
- the stepped piston is biased onto a sealing seat by spring force from the prestoring spring and is connected to the feed bore by a connecting channel;
- wherein fuel pressure from the fuel injection pump in the feed bore is controlled by the high pressure injection pump to reach a closure initiating pressure in the feed bore which is above an opening pressure and which causes the stepped piston to open and move the nozzle needle into a position corresponding to end preinjection and wherein the stepped piston has two piston parts of different sized diameters;
- the larger diameter piston part is guided in the nozzle body;
- and
- wherein the smaller piston part, together with the nozzle body, forms an annular chamber which can be connected to a connecting channel leading to the feed bore when the closure initiating pressure is reached.
Fuel injection device for an air compression and self-ignition internal combustion engine having preinjection and main injection, comprising:
- a high pressure multi-pump element injection pump with an injection line leading from each pump element to a line bifurcation which is connected to a main injection nozzle and to a feed bore of a preinjection nozzle;
- the preinjection nozzle having a nozzle needle moveably guided in a nozzle body;
- the nozzle needle being lifted off a value seat against the force of a restoring spring in response to fuel pressure in the feed bore and counter to a direction of flow of fuel in the feed bore;
- wherein the preinjection nozzle has a body in which a stepped piston is longitudinally displaceable;
- the stepped piston is biased onto a sealing seat by spring force from the prestoring spring and is connected to the feed bore by a connecting channel;
- wherein fuel pressure from the fuel injection pump in the feed bore is controlled by the high pressure injection pump to reach a closure initiating pressure in the feed bore which is above an opening pressure and which causes the stepped piston to open and move the nozzle needle into a closed position corresponding to end preinjection wherein the stepped piston is arranged coaxially which the nozzle needle and is provided with a closing pin which cooperates to close the nozzle needle;
- wherein the stepped piston has two piston parts of different sized diameters;
- the larger diameter piston part is guided in the nozzle body;
- and
- wherein the smaller piston part, together with the nozzle body, forms an annular chamber which can be connected to a connecting channel leading to the feed bore when the closure initiating pressure is reached.
Dependencies are inferred from the claim text.