Overflow Valve; Zero Delivery Drain; pressurizing part based on the amount of throttle- Page 126

ENGINE

L3560, L4060, L4760, L5060, L5460, L6060, WSM

1-M11

Overflow Valve

When the pressure of fuel delivered from the feed

pump  rises  above  a  prescribed  amount,  the  overflow

valve has a function of returning fuel to the tank and is

made up of a valve body (2), valve piston (5), spring (3),

and ball (1).

When fuel pressure increases and exceeds the force

of the spring, the valve piston is pushed. Here, the fuel

passes through the port (4) provided in the valve body

and returns to the fuel tank.

Therefore, the pressure in the suction control valve

is stabilized and fuel flow is accurately adjusted.

9Y1210824ENM0015US0

Zero Delivery Drain

The  zero  delivery  drain  (1)  has  a  function  of

preventing fuel flow to the pressurizing part when no fuel

is being delivered.

Though the suction control valve is set to no flow, a

small amount of fuel flows to the pressurizing part. The

zero delivery drain is provided to prevent this and this

small amount of fuel is returned through the zero delivery

drain and returned to the fuel tank.

NOTE

• Other than no delivery, fuel is delivered to the

pressurizing part based on the amount of throttle
and very little flows to the zero delivery drain.

9Y1210824ENM0016US0

(1) Ball

(2) Valve Body

(3) Spring

(4) Port

(5) Valve Piston

[A]  While Open
[B]  While Closed

(1) Zero Delivery Drain

KiSC issued 03, 2016 A