High-pressure fuel injection valve for an internal combustion engine
A high-pressure fuel injection valve may include a control valve having an actuator, a high-pressure fuel connection and a low-pressure fuel connection. A control plunger and nozzle needle are aligned longitudinally in the valve stem and the valve tip. Together with the control plunger, the receiving chamber of the control plunger forms a closing control chamber delimited by the upper control plunger surface, and an opening control chamber delimited by the lower control plunger surface. Each control chamber is hydraulically connected via a feed throttle to the high-pressure fuel connection and via a return throttle to the low-pressure fuel connection. The control valve opens and closes the fuel return between the return throttles and the low-pressure fuel connection depending on the operation. The flow values of the feed throttles and of the return throttles are selected such that the high-pressure fuel injection valve opens and closes based on actuation of the control valve.
1. A high-pressure fuel injection valve for an internal combustion engine connected to a fuel tank, comprising:
a fuel receiving chamber housing a single control piston having a piston upper side and a piston lower side and a nozzle needle arranged with respect to each other in a longitudinal direction,
wherein the nozzle needle is arranged on the lower side of the control piston which faces toward a nozzle tip having spray holes and interacts with a needle seat in the nozzle tip,
the fuel receiving chamber including:
a closing control chamber located on and in contact with the upper side of the control piston and defined by walls of the fuel receiving chamber and the upper side of the control piston housed within the fuel receiving chamber, the closing control chamber hydraulically connected to the fuel tank by a fuel high-pressure port via a first fuel feed throttle and to the fuel tank by a fuel low-pressure port via a first fuel return throttle to return fuel to the fuel tank,
an opening control chamber located on and in contact with the lower side of the control piston and defined by walls of the fuel receiving chamber and the lower side of the control piston housed within the fuel receiving chamber, the opening control chamber hydraulically connected to the fuel tank by a fuel high-pressure port via a second fuel feed throttle and to the fuel tank by a fuel low-pressure port via a second fuel return throttle to return fuel to the fuel tank, and
wherein the first fuel return throttle has a larger throttle aperture and a greater fuel throughflow value than the second fuel return throttle such that when a control valve is open, pressure falls more quickly in the closing control chamber than in the opening control chamber until a resultant force on the control piston opens the high-pressure fuel injection valve, and
wherein the first fuel feed throttle has a larger throttle aperture and a greater fuel throughflow value than the second fuel feed throttle, such that when the control valve is closed pressure builds up more quickly in the closing control chamber than in the opening control chamber until a resultant force on the control piston closes the high-pressure fuel injection valve.
2. The high-pressure fuel injection valve of claim 1 , wherein the nozzle needle directly contacts a lower control piston surface of the control piston.
3. The high-pressure fuel injection valve of claim 2 , wherein the nozzle needle has a smaller cross-sectional area than the lower control piston surface at a transition region.
4. The high-pressure fuel injection valve of claim 1 , wherein the control piston and the nozzle needle are continuously mechanically rigidly connected to one another.
5. The high-pressure fuel injection valve of claim 1 , wherein at least one of the two fuel return throttles has an adjustable aperture.
6. The high-pressure fuel injection valve of claim 1 , wherein at least one of the two fuel feed throttles has an adjustable aperture.
7. The high-pressure fuel injection valve of claim 1 , wherein the closing control chamber and the opening control chamber are further hydraulically connected by an equalization duct in communication with only the opening and closing chambers and having an equalization throttle arranged in the therein.
8. The high-pressure fuel injection valve of claim 1 , comprising a closing spring arranged in the closing control chamber, the closing spring being arranged in contact with and to mechanically act on the control piston.
9. The high-pressure fuel injection valve of claim 1 , comprising an electromagnet actuator or a piezo actuator configured to actuate the control valve.