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The term NO x represents several forms of nitrogen oxides such as NO (nitric oxide), NO 2 (nitrogen dioxide) and N 2 O (nitrous oxide, also known as laughing gas).In a gasoline engine, NO is the most common form of NO x at around 93%, while NO 2 is around 5% and the rest is N 2 O.
The most common soot-control device is a diesel particulate filter (DPF) installed downstream of the engine in the exhaust system. This captures soot but causes a reduction in fuel efficiency due to the back pressure created. Diesel particulate filters come with their own set of very specific operational and maintenance requirements. Firstly ...
DPR is a diesel particulate filtration system with regeneration process that uses late fuel injection to control exhaust temperature to burn off soot. [12] [13] Diesel engines manufactured after January 1, 2010 are required to meet lowered NOx standards for the US market.
This may be especially true for modern, clean diesel vehicles that continuously monitor engine operation electronically and actively control engine parameters and exhaust system operations to limit NO x emission to less than 0.2 g/km. Low-temperature combustion or LTC technology [2] may help reduce thermal formation of NO x during combustion ...
A NO x adsorber is designed to reduce oxides of nitrogen emitted in the exhaust gas of a lean burn internal combustion engine.Lean burn engines, particularly diesels, present a special challenge to emission control system designers because of the relatively high levels of O 2 (atmospheric oxygen) in the exhaust gas.
In 2007, Caterpillar developed the C13 and C15 Acert engines which used VVT technology to reduce NOx emissions, to avoid the use of EGR after 2002 EPA requirements. [16] [17] In 2010, Mitsubishi developed and started mass production of its 4N13 1.8 L DOHC I4, the world's first passenger car diesel engine that features a variable valve timing ...
The heart of the Mitsubishi's MVV system is the linear air–fuel ratio exhaust gas oxygen sensor. Compared with standard oxygen sensors, which essentially are on-off switches set to a single air/fuel ratio, the lean oxygen sensor is more of a measurement device covering the air/fuel ratio range from about 15:1 to 26:1. [19]
Many more engine parameters are actively monitored and controlled in real-time. There are about 20 to 50 that measure pressure, temperature, flow, engine speed, oxygen level and NOx level plus other parameters at different points within the engine. All these sensor signals are sent to the ECU, which has the logic circuits to do the actual ...