Charge air cooling

Air-to-air charge air cooling not only reduces NOx, it improves engine durability and increases low-speed torque and power density. It is the most efficient method of cooling intake air to help reduce engine emissions while maintaining low-speed torque, transient response time, and peak torque. Charge air cooling enables an engine to meet emissions with better fuel economy and lower installed costs.

In-cylinder solutions

Combustion bowl and piston ring design: Particulate emissions have been reduced on John Deere engines by increasing injection pressure and improving the shape of the combustion bowl at the top of the piston.

Premixed compression ignition (PCI): With premixed compression ignition (PCI), multiple fuel injection strategies are used to lower temperatures. This technique reduces NOx without using exhaust gas recirculation.

Exhaust gas recirculation

During certain conditions of engine operation, the EGR valve opens and measured amounts of exhaust gas are routed back into the intake manifold and mixed with the incoming fresh air. Since this process removes some oxygen from the air, the exhaust temperatures in the combustion process are lowered and the levels of NOx are reduced. Cooled EGR, as used in John Deere PowerTech Plus™ engines.

Turbocharging

Standard or wastegated turbocharger: Transient smoke is controlled by using higher-boost turbochargers, including using wastegated turbos that increase low-speed torque and prevent over-boosting at high speed.
Variable geometry turbocharger (VGT):  It minimizes the impact on engine envelope size and provides excellent performance across the entire operating range of the engine, including transient response and fuel economy

Fuel injection systems

High-pressure common rail fuel injection system: For middle range engines, the high-pressure common rail fuel injection system provides constant control over fuel injection variables such as pressure, timing, duration, and multiple injections.

Electronic unit injector (EUI): For the larger size engines, the EUI fuel injection system is used to increase fuel pressure for more efficient combustion. This helps reduce NOx and PM.

Mechanical fuel system: For smaller engines, mechanical fuel systems are able to generate higher injection pressures for more efficient combustion.

Full authority electronic controls
It uses sensors and models to control fuel quantity, injection timing, air-to-fuel ratio, multiple fuel injections, amount of cooled EGR, and a host of other control parameters to deliver peak engine performance and fuel economy.