Common rail fuel injection system
AssigneeDenso Corporation
InventorKoichi Nagai
Life of this patent
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Abstract
A pressure-reduction valve that returns fuel in a common rail to a low-pressure system is such one that a valve-opening pressure of the valve device is changed by an actuator into a target common rail pressure. Thus, when the actual common rail pressure in the common rail exceeds the target common rail pressure, the pressure-reduction valve opens at once. On the contrary, when the actual common rail pressure in the common rail decreases to reach the target common rail pressure, the pressure-reduction valve closes at once. Accordingly, the pressure-reduction valve limits an overshoot and an undershoot of the actual common rail pressure to a minimum without being influenced by a fuel temperature or by detection timings of the common rail pressure sensor.
Claims5
A common rail fuel injection system for an internal combustion engine comprising:
- a high-pressure pump that feeds a high-pressure fuel;
- a common rail that accumulates the high-pressure fuel fed by the high-pressure pump;
- an injector that injects the high-pressure fuel accumulated in the common rail;
- a target common rail pressure calculator that calculates a target common rail pressure in accordance with a driving state of the internal combustion engine;
- a valve device that opens when an actual common rail pressure in the common rail exceeds a predetermined valve-opening pressure to flow the high-pressure fuel in the common rail to a low-pressure system;
- and
- a valve-opening pressure changer that changes the valve-opening pressure of the valve device into the target common rail pressure.
Dependencies are inferred from the claim text.