EGR cylinder deactivation strategy to accelerate the warm-up and restart processes in a Diesel engine operating at cold conditions

Abstract

The aftertreatment systems used in internal combustion engines need high temperatures for reaching its maximum efficiency. By this reason, during the engine cold start period or engine restart operation, excessive pollutant emissions levels are emitted to the atmosphere. This paper evaluates the impact of using a new cylinder deactivation strategy on a Euro 6 turbocharged diesel engine running under cold conditions (−7°C) with the aim of improving the engine warm-up process. This strategy is evaluated in two parts. First, an experimental study is performed at 20°C to analyze the effect of the cylinder deactivation strategy at steady-state and during an engine cold start at 1500 rpm and constant load. In particular, the pumping losses, pollutant emissions levels and engine thermal efficiency are analyzed. In the second part, the engine behavior is analyzed at steady-state and transient conditions under very low ambient temperatures (−7°C). In these conditions, the results show an increase of the exhaust temperatures of around 100°C, which allows to reduce the diesel oxidation catalyst light-off by 250 s besides of reducing the engine warm-up process in approximately 120 s. This allows to reduce the CO and HC emissions by 70% and 50%, respectively, at the end of the test.

Numerical modelling and non-dimensional analysis of a diesel oxidation catalyst with focus on NO2 reduction

“…Engine cold start and warmup period, frequent engine shut-off and restart, typically encountered in hybrid vehicles, active regeneration of DPF and various low temperature combustions (LTC) strategies lead to either low exhaust gas temperature or high magnitude of emissions or both [12][13][14][15] and hence, the conversion efficiency of the DOC becomes challenging. Stringent CO 2 emissions regulations, aimed at improving the thermal efficiency of the engines, consequently reduces the exhaust gas temperature and poses challenges for DOC functioning.…”

“…In the washcoat, interdependent diffusion and heterogenous chemical reactions occur. It is worth mentioning that, generally, in the numerical models, both for actual exhaust and flow reactor artificial exhaust conditions, only the external mass transfer limitations of the exhaust gas species from open channel to the flow-channel interface was considered [6][7][8][9][10][11][12][13][14][15][16][17] and the internal diffusion phenomenon was ignored. In some other numerical models, the internal mass transfer phenomenon for CO and THC oxidation reactions were only considered.…”

Increase in the Fuel Efficiency of a Diesel Engine by Disconnecting Some of Its Cylinders

“…The works of scientists [10][11][12][13][14][15] deal with complex issues of a more complete additional loading of the cylinders remaining in operation, a decrease in specific and liter fuel consumption, and an increase in fuel efficiency.…”

Environmental control of the technical condition of electromagnetic nozzles of internal combustion engines

“…Cylinder deactivation [7][8][9][10][11] methods are also fairly widely known. However, in addition to a whole number of cylinders, individual cycles [12][13][14][15][16][17] can also be deactivated. This impacts the fuel supply and gas distribution units [18].…”