Fig. 2.97. Structural diagram of the K-Jetronic fuel injection system.
I — fuel tank; 2 - fuel pump; 3 - pressure accumulator; 4 - fuel filter; 5 — air intake; 6 - air filter; 7 — air filter housing; 8 - electromagnetic shut-off valve of forced idle speed; 9 — fuel dispenser; 10 — control pressure regulator; 11 — air flow meter pressure disk; 12 — additional air supply valve; 13 — throttle body; 14 — receiver; 15 - electromagnetic starting nozzle; 16 - fuel injector; 17 — inlet manifold.
Thin lines indicate fuel lines, wide lines indicate air lines.
Then the fuel enters the fuel distributor 9 under pressure through the filter 4. The pressure disk 11 of the air flow meter, fixed on the movable lever between the air filter 6 and the throttle valve 13, deflects depending on the vacuum in the intake manifold 17. The movement of the pressure disk of the air flow meter is transmitted to the distribution spool of the distributor, determining the amount of fuel supplied to the engine cylinders and ensuring the optimal composition of the fuel-air mixture. The control pressure regulator 10 reduces the pressure on the distribution spool of the distributor during engine warm-up, which causes an increase in fuel supply, i.e. enrichment of the combustible mixture. The additional air supply valve 12, installed in the air duct, made parallel to the throttle valve. supplies an additional amount of air to the engine when starting and warming up a cold engine, which leads to an increase in the crankshaft speed at idle. To facilitate starting a cold engine, an electromagnetic starting injector 15 is provided. The duration of opening of which is determined by a thermal time relay depending on the temperature of the coolant.
Data for adjustment:
- crankshaft speed at idle 750-850 rpm;
- carbon monoxide (CO) content in exhaust gases 1.0-1.5%;
- fuel pressure in the system 4.7-5.5 kgf/cm²:
- control pressure/at engine temperature,°C: 0.9 kgf/cm²/10°C: 1.35 kgf/cm²/20°C; 1.7 kgf/cm²/30°C; 2.15 kgf/cm²/40°C;
- control pressure on a hot engine 3.4-3.8 kgf/cm²;
- residual fuel pressure in the system: 10 minutes after stopping the engine 2.5 kgf/cm², after 20 minutes - 2.0 kgf/cm²;
- injection start pressure 3.2-4.0 kgf/cm².
Fuel tank
The 48-litre fuel tank is mounted under the body bottom in its rear section. The fuel tank pipes have a larger diameter than the fuel tank pipes of cars with carburetor engines.