Diesel Engine Emission Control Technologies

We have created a short video to describe the main emission control systems used in diesel engines, to highlight the disadvantages of each, and explain why DrunkLab has put so much effort into creating EGR, DPF and SCR removal solutions for commercial vehicles.

The scheme of the diesel engine operation #

Combustion chamber #

Fuel combustion takes place in the combustion chamber, as a result DPM (soot) and NOx (nitrogen oxides) are produced, which are later released into the atmosphere through the exhaust line.

Exhaust line #

The exhaust line is designed to release the exhaust gases DPM (soot) and NOx (nitrogen oxides).

Exhaust gases #

Fuel combustion result: DPM (soot) and (nitrogen oxides) NOx.

Emission control systems #

To reduce emissions into the atmosphere (DPM and NOx), manufacturers have developed exhaust gas after-treatment systems:

The EGR system #

Exhaust Gas Recirculation is designed to reduce NOx emission, the principle of its operation is to redirect (up to 50%) exhaust gases back into the intake manifold.

Disadvantages of the EGR system: #

• increases of the fuel consumption,
• decreases of the engine power,
• leads to non-efficient fuel combustion,
• increases the DPM (soot) emission

DPM (soot), gets into the engine oil, turns into an abrasive, which increases wear and tear of the engine and reduces its lifetime.

The DPF system #

Diesel Particulate Filter is a fine filter designed to retain DPM (soot) and therefore reduce DPM emissions.

Disadvantages of the DPF system: #

• Reduces engine efficiency,
• Increases exhaust back pressure.

DPF RE-GEN (burn) #

The filter regeneration process occurs by increase temperature to 1100 ⁰C inside the DPF, due to injection of additional fuel into the engine combustion chamber.

Consequences of an irregular/incorrect DPF regeneration process:

• the DPF system is clogged;
• reduction in engine efficiency.

The DEF & SCR Systems #

Designed to eliminate nitrogen oxides (NOx).

SCR means Selective Catalytic Reduction,

DEF (Diesel Exhaust Fluid) is a liquid (urea) consisting primarily of ammonia (NH3).

Operating principle: #

1. The control unit sends a signal for urea injection (NH3) into the SCR.
2. During the chemical reaction: (NH3+NOx=H2O+N2), water and nitrogen are produced.

Operational problems of the DEF & SCR: #

• if the DEF level is insufficient, the vehicle goes into emergency mode, the speed drops to 5 MPH;
• if the DEF is not updated in timely manner and/or temperature drops occur, the urea may crystallize, in this case the engine will not be able to start until the problem is fixed!