Volvo 819 E - Page 55

Group 28 Ignition systems
Design and funct ion - System descriptions
1
19
EZ-118K
EZ·118K - Fuel cut-off
(B 230 K var i ants only )
The
control unit (1) supplies a signal to the sole no id valve (25) under engine braking condi tion s (when the eng ine
speed is high) prov i ded that the i dling switch (19) simul tane ously indicates that the throttle is close d. The solenoid
valve opera te s to cut off the supp ly of fuel with the aid of a vacuum valve mounted on the carburettor .
The con trol unit grounds the solenoid valve, thereby ac ti vating th e fuel cut-off function when th e engine speed is
higher than approx. 1650 r/ min (1610 r/ min on 1985-86 model s and 1700 rl min on 1987 and later models) and the
idling switch is closed.
The ground connection is opened and the fuel supply is restored when the eng ine speed has fallen to approx . 1550
r/min
or when the accelerator is depressed .
The fuel c ut - off fun c tion operates only if the engine temperature is h igh er than approx . 85 °C.
• The f uel cu t-off functi on reduces the fuel consump t ion and , as a result, the volume of eJlhaust gases.
• The i dling sw it ch wa s tran sferred from the accele rator pedal to the thronle pulley in 1987. the same year in wh ich the EZ -118K
control uni t for the B 230 K engine was pr ogrammed with new t imi ng Curves as part of the redesign of the combus t ion chamber .
On
its i ntroduct ion, the new engine was designated B 230 KH , t he H st anding lor 'Heron'. In t he service literature , K eng ines are
now identified bV stati ng the year, for eJla mple B 230 K, 1987 -.
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