Short communicationThe real driving emission characteristics of light-duty diesel vehicle at various altitudes
Introduction
Great utilization of diesel vehicles contributes to the large-scale pollutant emissions to atmosphere, and thus results in the growing concern about civil ambient air and human health (Yang et al., 2017a). It is well known that some factors such as vehicle weight, fuel, driving pattern, exhaust after-treatment device and altitude will influence the exhaust emissions. Among them, altitude is pretty important because both the local air pressure and oxygen content decrease with the increasing altitudes. As a result, the power output reduces (Benjumea et al., 2009; He et al., 2011; Zhang et al., 2016a); the in-cylinder combustion of diesel engines deteriorates (Liu et al., 2017); the fuel consumption rises and thermal efficiency decreases (Wang et al., 2013b). Especially, in comparison with the operation at near sea level, the vehicle emissions are larger at high altitudes (Human et al., 1990). In addition, there are a lot of high altitude cities among the world. In China, the area of high altitude regions with altitude higher than 1000 m could be approximately 65% of territory. Among these regions, the altitude above 2000 m accounts for 33% (Yu et al., 2014). Hitherto, more than 15 million vehicles are registered within these regions. Moreover, the total vehicles registered population in some high altitude provinces, such as Yunnan, Qinghai and Tibet, occupies 20% of China's vehicle population. (Liu et al., 2017; MEP, 2017). Increasing vehicle emissions are generated every day. Thus, it is important to effectively control emissions in these regions.
Hitherto, there are numerous publications focused on the influence of altitude on the diesel vehicles performance. Wang et al., 2013a, Wang et al., 2013b investigated the effects of altitude on the thermal efficiency and emission characteristics of a Euro III diesel engine by mobile engine test bench and a portable emission measurement system (PEMS). The results showed that thermal efficiency decreased with altitude and regular pollutions, and particulate matter (PM) increased with altitude. Liu et al. (2014) reported that the soot emission decreased with the rising pressure by using simulated device. Chan et al. (2011) studied the gaseous and particle emission characteristics of a turbojet engine at simulated altitudes. They found that the emissions of CO2, NOx and particle number were lower and the emissions of CO and THC were larger at higher altitudes in comparison with that of lower altitudes. Benjumea et al. (2009) demonstrated the combustion process of a high speed direct injection automotive diesel engine operating at altitudes between 500 and 2400 m and found that both fuel consumption and combustion duration increased with altitude. From the aforementioned references, employing both test benches at actual altitude and altitude simulation system may be helpful. However, the simulation method may result in some unwanted uncertainties. In addition, there exists gaps between the emissions using test benches and real-world driving emissions, as a minor change in the ground speed of test vehicle will lead to great change in engine operating conditions (Yanowitz et al., 2002; Yin et al., 2013).
To avoid the disadvantages above, the measurement of the real road driving emissions was adopted by numerous reports about vehicle emission tests operating at high altitude. Yin et al. (2013) evaluated regulated emissions and PM distributions of a light duty diesel at different altitudes; however the test was performed at idle mode. Ramos et al. (2016) studied the effect of altitude on emissions from a light duty vehicle under real world driving conditions and found that NOx emissions increased with altitude. However, their test operated at urban and extra-urban driving conditions without considering motorway driving condition. Liu et al. (2017) discussed the influence of altitude on the particle numbers and their size distribution in two Chinese cities, while the test vehicle did not incorporate after-treatment device. In addition, China VI regulation will be implemented from 2020, which will introduce real driving emission (RDE) test procedure and stipulate the altitude test requirements.
In this work, the emission characteristics from a China IV certificated light-duty diesel vehicle at different altitudes under real driving conditions were investigated. The related conclusions from this work can elucidate the emission characteristics under RDE conditions and provide useful information for policy-making process.
Section snippets
Test vehicle and experimental equipment
The vehicle used in this work was HAVAL H6 with a 6-gear manual transmission, which was powered by a 2.0 T, in-line, 4-cylinder, variable geometry turbocharger (VGT) engine (GW4D20). It was manufactured by Great Wall Motor Company Limited. The vehicle was equipped with exhaust gas recirculation (EGR), diesel oxidation catalyst (DOC) and diesel particle filter (DPF), which could meet China IV standard that is compliant with Euro IV. The original electronic control unit was not adjusted during
Results and discussion
Fig. 5 illustrates the influence of altitude on CO emissions. It is noticed from Fig. 5a that increasing altitudes are favor for CO emissions except for the case of 2240 m. Specifically, CO emission at the altitude of 2990 increases by 209% comparing to that of 30 m. Thus, it indicates that the combustion in the in-cylinder becomes worse at higher altitude region. The atmospheric pressure is much less than that of near sea level. At the altitude below 5000 m, the pressure reduces by 100 Pa with
Conclusions
To elucidate the effects of altitude on the emissions under RDE conditions, CO, NOx and PN emissions from a China IV certificated light-duty diesel vehicle at six altitudes were tested and analyzed. The relevant conclusions drawn from this work can be summarized as follows:
- (1)
CO emissions increased with altitude and the CO emission at the altitude of 2990 m increases by 209% comparing to that near sea level in whole test cycle. At specific test modes, CO emissions follow the sequence of
Acknowledgements
This research is sponsored by National High-Tech Research and Development Program (Grant No. 2016YFC0208005), Graduate Technological Innovation Project of Beijing Institute of Technology (Grant No. 2018CX10016) and National Natural Science Foundation of China (Grant No. 5157060575, 51576016 and 51476012).
References (24)
- et al.
Effect of altitude and palm oil biodiesel fuelling on the performance and combustion characteristics of a HSDI diesel engine
Fuel
(2009) - et al.
Emission characteristics of a heavy-duty diesel engine at simulated high altitudes
Sci. Total Environ.
(2011) - et al.
On-board measurement of particle numbers and their size distribution from a light-duty diesel vehicle: influences of VSP and altitude
J. Environ. Sci. China
(2017) - et al.
Effects of altitude and fuel oxygen content on the performance of a high pressure common rail diesel engine
Fuel
(2014) - et al.
Performance, combustion timing and emissions from a light duty vehicle at different altitudes fueled with animal fat biodiesel, GTL and diesel fuels
Appl. Energy
(2016) An assessment of Pt and Pd model catalysts for low temperature NOx adsorption
Catal. Today
(2016)- et al.
Effects of altitude on the thermal efficiency of a heavy-duty diesel engine
Energy
(2013) - et al.
On-vehicle emission measurement of a light-duty diesel van at various speeds at high altitude
Atmos. Environ.
(2013) - et al.
Idle emission characteristics of a light-duty diesel van at various altitudes
Atmos. Environ.
(2013) - et al.
Experimental investigation of the impact of biodiesel on the combustion and emission characteristics of heavy duty diesel engine at various altitudes
Fuel
(2014)
Interactions of nitric oxide with various rank coals: implications for oxy-coal combustion flue gas sequestration in deep coal seams with enhanced coalbed methane recovery
Fuel
Gaseous and Particle Emissions from a Turbo-jet Engine Operating on Alternative Fuels at Simulated altitudes
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