Exhaust After-Treatment
Catalytic converter
Tougher exhaust emissions restrictions place high demands on effective exhaust after-treatment. A CCC (Close Coupled Catalyst) is used for both petrol and diesel variants of the VEA engines. The catalyst's compact design and its location close to the engine enables very fast heating, good flow and efficient purification.
The close coupled catalytic converter is similar to the one introduced on the D5254T10 for 10W20. For the petrol engine in the VEA family, there are 3 different catalytic converters, of which 2 are externally identical. The difference between them is the number and type of substrate, which also affects the catalytic converter's overall length. The catalytic converters' active materials are platinum, palladium and rhodium in varying amounts, depending on the market. The front lambda probe is of the broadband type and has linear signal characteristics. The remaining two lambda probes have binary signal characteristics.
Lambda probes
The petrol engines have two or three lambda probes depending on the engine's emission rating. The B4204T10/T12 engines intended for markets which correspond to PZEV (Partial Zero Emission Vehicle) have three lambda probes. These engines also have two catalytic converter monoliths. The B4204T9/T11/T15 engines intended for other markets have two lambda probes and one catalytic converter monolith. The front lambda probe has, for all engine options, a linear signal characteristic, while the rear has binary. To provide a fast operating temperature, all lambda probes have a heating element which is controlled by the ECM. The lambda probes reach normal operating temperature within a few seconds.
Crankcase ventilation
In an internal combustion engine, crankcase ventilation is important to clean engine oil and separate it from the residual gases that pass piston rings and valve seals, so called blow-by.
In a supercharged engine where the extra boost pressure in the engine affects the amount of blow-by, it is very important to have correctly sized crankcase ventilation that can take care of the extra supply of waste gases that boosting causes. The crankcase ventilation on the engines in the VEA family is pressure controlled and completely closed. The system comprises, in addition to the internal channels in the engine block, of an oil separator in plastic placed on the cam cover and a hose between the separator and the fresh air pipe.