3B-0 GROUP 3B CLEANER AIR SYSTEM CONTENTS SECTION 0 GENERAL 1 2. Removal and Installation 3 3 SECTION 1 SUB TANK 2 2-2 Installation 3 2 2-3 Inspection and Maintenance 3 2. Removal and Installation 2 9 SECTION 3 PURGE VALVE 3 2-2 Installation 2 3 SECTION 2 CANISTER 2 2. Inspection and Maintenance 4 2
CLEANER AIR SYSTEM :13-11 SEC. 0 GENERAL Emission pipe Purge valve Canister Vacuum motor Sub tank Emission hose Throttle positioner Fuel tank Fig. 1 Cleaner Air System The fuel system of this engine is provided with a sub tank for separation of vapor from the fuel, a canister for absorption of evaporative gases generated in the fuel tank, and a purge valve which admits the fresh air from the outside into the canister during driving. This equipment is employed to prevent the evaporative gases from being discharged into the atmosphere. Fig. 1 shows the Cleaner Air System. Purge control valve Canister Purge air Paper filter Sub tank Sealed cap Fuel tank Fig. 2 Details of Cleaner Air System
3B-2 CLEANER AIR SYSTEM SEC. 1 SUB TANK The construction of the sub tank is as shown in Fig. 3. Its duty is to momentarily reduce the overflowing quantity of gasoline in the fuel tank caused by temperature rise and also to sub tank for the purpose of preventing solid gasoline from entering the vapor line in extreme cornering. 2. Removal and Installation (1) Remove hose attaching clip and pull hose off tube. (2) Remove clip from left front part of shelf trim. (3) Remove attaching bolts. (4) Remove attaching bolts from inside trunk. (5) Take out sub tank body. NOTE: In the station wagon, first remove the left rear side trim. 2-2 Installation When installing the sub tank, observe the following items. (1) Insert hose onto tube and securely clamp it. (2) Either tank or hose that has any damage should be replaced. To filler neck To vapor line To hose at the rear of fuel tank To hose at the front of fueltank Fig. 4 Sub Tank (Sedan, Hardtop), To filler neck (1) Liquid tube (4) Attaching bolt (2) Vapor tube (5) Shelf trim (3) Sub tank Fig. 3 Sub Tank To hose at the rear of fuel tank To hose at the front of fuel tank \ To hose at the center of fuel tank To Vapor line Fig. 5 Sub Tank (Station Wagon) SEC. 2 CANISTER It is likely that much of hydrocarbon is discharged into the atmosphere because of breathing caused by changes of fuel tank temperature and fuel vapor generated within the fuel tank. To prevent this, the vapor is led into the canister that traps gasoline with charcoal while the engine is stationary. During engine operation, however, the fresh air is drawn into the canister to carry gasoline off from the charcoal into the suction system, through which the gasoline is brought into the combustion chamber. This operation is repeated while the car is in operation, so that the charcoal
CLEANER AIR SYSTEM 3B-3 From fuel tank Paper filter 41- From purge valve to intake manifold Fig. 6 Construction of Canister will never be excessively loaded with the gasoline. The construction of this device is as illustrated. A paper filter type air cleaner for trapping dirt present in purge air and a paper filter for removal of charcoal are installed before and behind the charcoal. (1) (2) (3) (4) (5) Canister body Filter Strainer Plate (6) (7) (8) (9) (10) Spring Plate Spacer element Cup Fig. 7 Details of Canister (1) Securely tighten each clamp. (2) Replace hose if it has a crack. (3) Inserting tube into hose can readily be done by applying a small amount of grease to tube I.D. 2. Removal and Installation 2 3 Inspection and Maintenance V - (1) (2) (3) (4) Remove hose clamp at canister side. Loosen purge valve attaching bolts. Remove hose clamp from sub tank. Remove canister attaching bolts. 2 2 Installation - When installing the canister, observe the following items. (1) Replace filter paper and air cleaner element every year or every 12,000 miles of driving. (2) Replace charcoal every 50,000 miles of driving. (3) When replacing charcoal, remove carbon dust if possible. (4) Recharging of charcoal should be done in such a place free of organic gases and water drips. (5) Amount of charcoal required is 8.8 ± 0.1 oz. SEC. 3 PURGE VALVE The purge valve admits fresh air into the canister to blow vapor gas off the activated charcoal and carry the gas away into the engine. During engine operation, the valve is kept open, but when the engine is stationary, it is closed to shut off the purge air. Its construction is as shown in Fig. 8. The venturi boost acts on the back side of the diaphragm, and the more the engine speed increases, the more the boost grows, thus opening the valve wider to supply an increased amount of purge air to the canister. Fig. 8 Purge Valve External View
3B-4 CLEANER AIR SYSTEM 2. Inspection and Maintenance Purge control valve must be checked every 24,000 miles. Inspection and service procedure are as follows: (1) With no venturi boost applied to the purge control valve, exert a vacuum of 19.69 inhg to the intake side of the intake manifold. At this time, if the flow rate of the purge air is less then 0.071 cu.ft./min., the valve is in a satisfactory condition. (2) If the flow rate of the purge air exceeds 0.071 cult/min. and the engine fails to idle efficiently, the purge control valve must be replaced. To primary venturi of carburetor Spring From canister To intake manifold Fig. 9 Purge Valve Sectional View