Contents: Crankcase ventilation system ↳ Emission control system ↳ Exhaust gas recirculation (EGP)… ↳
1. Some engines in the Transit Diesel series are equipped with systems designed to reduce the emission of harmful combustion by-products into the atmosphere.
2. The following systems can be installed according to the model.
Crankcase ventilation system
3. Crankcase ventilation system is installed on all models.
4. Fuel vapors and exhaust gases (through piston rings) are diverted from the crankcase and from the valve covers through the oil filler cap into the intake manifold. These gases are then introduced into the engine for combustion.
Emission control system
5. To minimize the level of harmful substances in the exhaust gases, a catalytic converter is installed, which is located in the exhaust system.
6. The catalytic converter consists of a housing that contains a mesh with a large number of fine holes impregnated with catalyst material, through which the exhaust gases pass. The catalyst accelerates the oxidation of carbon monoxide, unburned hydrocarbons and soot, and effectively reduces the amount of harmful substances released into the atmosphere.
Exhaust gas recirculation (EGP) system
7. This system is designed to return a small amount of exhaust gases to the intake manifold, i.e. to the re-burning process. This reduces the level of nitrogen oxides in the exhaust gases emitted into the atmosphere.
8. The volume of exhaust gases returned to the inlet is regulated by vacuum (obtained from the exhaust manifold after the throttle) through the EGR valve installed on the exhaust manifold or turbocharger. Before reaching the EGR valve, the vacuum from the manifold passes to the vacuum valve, which changes it according to operating conditions.
9. The throttle valve, mounted on the intake manifold, allows you to regulate the ratio of air and exhaust gases. The throttle also directs exhaust gases into the intake manifold both at idle and under light load. Without the throttle, the intake manifold would be at atmospheric pressure, and the vacuum created by opening the engine intake valves would not be able to force the exhaust gases to circulate.
10. On turbocharged engines since 1992, the EGR system is used in conjunction with the Lucas EPIC engine management system (electronic injection control system). The EGR system is controlled by the EPIC electronic control unit, which receives engine operating information from the accelerator pedal position sensor, manifold pressure sensor, crankshaft position and speed sensor, coolant temperature sensor and air temperature sensor.
11. The general operating principles of the EGR system remain essentially unchanged, but before reaching the EGR valve, the vacuum from the manifold passes through a vacuum flow regulator mounted on the bulkhead of the engine compartment. This regulator varies the vacuum supplied to the EGR valve based on information received from the Lucas EPIC system's electronic control unit.
12. Since 1995, some turbocharged models have been equipped with an intermediate cooling system for the EGR system, included in the engine cooling circuit.