|
(11) | EP 0 902 181 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
|
|
|
|
|||||||||||||||||||||||
| (54) | Variable-discharge-rate high-pressure pump |
| (57) An object of this invention is to reduce the drive torque required by a variable-discharge-rate
high-pressure pump. The reduction in the drive torque enhances the durability of a
timing belt used in a mechanism for power transmission to the high-pressure pump.
The high-pressure pump has a plurality of cylinders (2a, 2b). A pair of plungers (21a,
21c) are disposed in the cylinder (2a). A pair of plungers (21b, 21d) are disposed
in the cylinder (2b). A pressure chamber (23a) is defined between opposing end surfaces
of the plungers (21a, 21c). A pressure chamber (23b) is defined between opposing end
surfaces of the plungers (21b, 21d). Low-pressure fuel which is metered by an electromagnetic
valve (6) for flow rate control is sequentially fed to the pressure chambers (23a,
23b). An inner cam (8) is provided which drives the plungers (21a, 21b, 21c, 21d).
The inner cam (8) is common to the plungers (21a, 21b, 21c, 21d). Fuel pressurization
and fuel pumping are alternately implemented in the pressure chambers (23a, 23b) in
accordance with rotation of the inner cam (8). According to the alternate fuel pressurization
and fuel pumping, the peak value of the drive torque required by the high-pressure
pump can be reduced. |