Technify Motors Cessna 172, Руководство по обслуживанию

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Supplement Airplane Maintenance Manual
Cessna 172 with TAE 125-02-99 / -114
AMM-20-02
Rev. No:
Rev. Date:
Chapter:
Issue:
Issue Date:
Page:
Content: 20-AMM-73-02
3
06.11.2013
3
10
1
25.08.2014
High Pressure Pump
The high pressure pump is an outlet-camshaft driven
radial-piston-pump, which pressurizes the common rail with up to
1350 bar (19580 psi). The HPP is the interface between the low
pressure and the high pressure stages. In contrast to
conventional systems, the HPP continually generates the rail
pressure so the fuel does not have to be specially compressed
for the injection process.
An eccentric drive shaft moves the 3 pistons of the pump up and
down in accordance with the shape of the cam. The feed pump
forces fuel through the inlet valve into the pumping element
chamber and the down moving piston sucks the fuel into the
cylinder. Passing the BDC the inlet valve closes and the fuel can
now be compressed. As soon the pressure in the cylinder is
higher than the rail pressure, the outlet valve opens and the fuel
enters the high pressure circuit.
Several parts of the HPP have got a special coating to ensure the
operation with diesel and jet fuel in any mix-ratio. See Figure 3.
Figure 3 High Pressure Pump
1 Driveshaft
2 Eccentric cam
3 Pumping element with Pump Piston
4 Inlet Valve
5 Outlet Valve
6 Inlet
1
2
3
4
5
6