The governor is bronze-bushed throughout, and all parts are oiled by the single sight Oiler. Beyond renewing the bushings when worn and seeing that the governor is lubricated, the oper ator has little trouble with it. The teeth in gear and pinion will wear slightly after some length of service. This has but little effect since the change in the admission angle, due to back lash at the pinion, is very slight.
Primm Injection pump is outlined in Fig. 315. The body of the pump is a bronze casting mounted in a cast-iron housing or support. This pump is fibrous packed, being provided with a gland and a screwed stuffing-box nut. The plunger is - - positively driven by the eccentric rod and is equipped with a return spring. The valves are rather different from accepted oil engine designs. It is claimed that the fiat seats facilitate re grinding. Since the fuel used is ordinarily filtered, the danger of grit getting under the valves is remote. The operator should give these valves attention, for it requires less cutting to injure flat valves than ball or bevel-seated poppet valves. The stuffing box should be repacked every few months. A good many operators have the habit of pulling a new ring behind the old packing when a leak develops. The only correct. method of stopping seeping around the plunger is the renewal of the entire packing.
De La Vergne Governor and Fuel governor, Fig. 316, used on the D.H. engine is the De La Vergne standard fly ball type and is driven by bevel gears from the cam or layshaft A. The governor controls the engine speed by regulation of the amount of oil entering the combustion chamber. This is achieved by means of a by-pass valve B. The fuel pump is driven by a cam C on the layshaft. The pump stroke is constant, handling a fixed quantity of oil. Connected with the discharge line is the by-pass valve B. This valve is opened and closed by means of a push-rod D actuated by a cam on the layshaft. The lever which opens the poppet by-pass valve is fulcrumed on a pin which is linked to the governor collar E. It is evident that, if the governor balls rise and lift the collar, the fulcrum pin will move to a lower position. This allows the reach-rod lever to touch the valve stem B earlier in the cycle. Early valve opening causes most of the fuel charge to by-pass back into the return line F. On heavy loads the action is the reverse of the above.
This governor, then, is of the constant injection type. The timing of the injection period depends on the load on the engine; Fig. 317 gives the valve timing. The velocity of injection is
constant at all loads; the atomization is as successful at low loads as at the heavy loads. To this may be attributed the excellent fuel economy at all loads. Since the slightest movement of the fulcrum pin affects the valve opening, a small amount of wear will alter the fuel consumption. The links and pins must be replaced at the first evidence of wear.
Buckeye-Barrett Oil Engine Governor.—This engine uses a vertical centrifugal governor which is driven from the cam shaft by a bevel gear. The method of drive is shown in Fig. 275. The mode of governing is by the shifting of the fulcrum point ' of the lever controlling a by-pass valve. This is shown in Fig. 318, which gives a cross-section of the fuel pump.
Buckeye-Barrett Fuel Pump.—The fuel pump. consists of a plunger cavity together with the suction and discharge valves, and the by-pass valve A. In operation the pump plunger is driven by the push-rod B, which, in turn, receives its motion from a cam formed on the governor gear shaft; see Fig. 275. This plunger, as it moves inward, forces the oil up through the discharge valve C into the fuel line to the nozzle. The oil is injected through the nozzle until the lever D, which is moved by the pump plunger, engages the stem of the by-pass valve. The opening of this by-pass valve relieves the pump discharge and thus prevents any additional amount of oil from reaching the nozzle.
If the load becomes lighter, the movement of the governor weights and the reach-rod F causes the fulcrum to move outward. This enables the lever D to strike the by-pass valve stem earlier, reducing the quantity of fiiel entering the nozzle. The fuel plunger begins the injection of the fuel when the crank is approxi mately 40 degrees ahead of dead-center, continuing some 20 degrees, dependent on the load carried. The regulation of the fuel injection is by means. of the by-pass valve alone. This can be made to open at any desired point by adjustment of the stem end. In resetting this, the governor should be blocked in its greatest outward position. The engine should then be turned over by hand and the valve stem adjusted so that the valve is opened as soon as the plunger begins its discharge stroke. If it is desired to change the timing of the injection, it is possible to shift the cam gear one tooth, which will cause the plunger to move earlier or later, according to the direction in which the gear was shifted.