Volvo 819 E - Distributor

Group 28 Igni t ion sys t ems
Design and function - Components
A
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Distributor
Function
The function of the distributor is to conduct the high-tension pulse from the ignition coil to the appropriate spark
plug . A distributor fitted with a Hall generator also provides information on engine speed with the aid of the trigger
rotor driven by the distributor shaft.
Construction and variants
The distributor consists of a cap (1), rot or arm (2), shaft (3) and, in applicable cases, a Hall generat or (4) and trigger
rotor (5). (Older systems employ either contact breaker points or some form of pulse generator.)
A. 'Vertical'
distributors are driven by an intermediate shaft through bevel gearing.
B. 'Horizontal' distributors are driven directly from the camshaft, minimizing the play in the transmission mechan -
ism. This , in turn , affords more accurate control of the timing in systems in which speed information is supplied
by a Hall generator .
700 series
models from 1985 on (with the exception of the 740 with the B230A engine) are fitted with camshaft -
driven units.
In the case of distributors which are not equipped with a Hall generator and , as a result, are fitted only with a rotor
arm , the timing cannot be varied by rotating the unit. In systems of th is type , since crankshaft position signals are
supplied by an inductive pick-up at the flywheel , only the position of the rotor in relation to the contacts in the cap is
altered
by this procedure .
• The TZ-28H system employs a distributor. with a vacuum advance un it to supply engme load in fo rmation .
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