Influence of ambient temperature on diesel engine raw pollutants and fuel consumption in different driving cycles

Abstract

The effect of low ambient temperature on diesel raw pollutant emissions is analysed in two different driving cycles: NEDC and WLTC. The study is focused on hydrocarbons, carbon monoxide, nitrogen oxides and fuel consumption. Tests are conducted at cold start in a HSDI light-duty diesel engine with two levels of ambient temperature: 20 °C and −7 °C. Results showed a general detriment of pollutant emissions and break thermal efficiency at low ambient temperatures. NOx is increased around 250% in both cycles when running at low temperatures. Effect on hydrocarbons is more noticeable in the NEDC, where it rises in 270%, compared with the 150% of increase in the WLTC. In the case of carbon monoxide, uncorrelated tendencies are observed between both driving cycles. Concerning the NEDC, carbon monoxide emissions increase up to 125%, while at the WLTC, they are reduced up to 20%. Finally, from the point of view of the thermal efficiency, a reduction of nearly 10% in the NEDC is observed. However, no fuel penalty is spotted regarding the WLTC.

Impact of driving dynamics in RDE test on NOx emissions dispersion

“…This has created demand for alternative means of ensuring product compliance early in the development process without the need for costly on-vehicle testing, and the engine testing is an important solution to understand effect of such uncertainties. The dispersion for WLTP cycle due to ambient temperature has been shown by Luján et al 7 On similar lines, the impact of driving dynamics is investigated using an engine test bench facility. In particular, this article presents a real drive NO x emission study using a drive cycle generator capable of creating synthetic routes with variable driving dynamics and fulfilling RDE testing protocols.…”

“…In order to see the trend of emissions due to dynamics, two variables-(v Á a pos 95 ) avg and (RPA k ) avg are defined as an average of trip dynamics in equations (6) and (7) v Á a pos 95 À Á avg =…”

“…In the article by Cuenot, 12 a considerable dispersion has been reported in the driving dynamics of average drivers and vehicles. The dynamics are found to exceed the upper boundary limits, defined in equation (7). In the article by Miller and Franco 13 , it has been shown that the driving conditions (including unusually cold or hot ambient temperatures, driving dynamics, driving at high speeds, driving at higher altitude and diesel particulate filter regeneration events) not covered by the RDE test have a relatively high contribution to overall NO x emissions.…”

Establishing the regularities of correlation between ambient temperature and fuel consumption by city diesel buses

“…The combustion process is significantly affected by the nonoptimal thermal conditions of the engine. A decrease in ambient temperature makes it difficult to start a diesel engine because of increased kinematic viscosity and density of diesel fuel [14]. Diesel parameters such as viscosity, density, and surface tension affect the fineness of spraying, completeness of combustion, and fuel consumption.…”

High-pressure exhaust gas recirculation line condensation model of an internal combustion diesel engine operating at cold conditions

“…Exhaust gas recirculation (EGR) is a widely used technique to fulfill the current NOx emission regulations, 3,4 even at cold conditions. 5…”