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Technical Paper

Investigating the engine behavior of a hybrid vehicle and its impact on regulated emissions during on-road testing.

2019-12-19
2019-01-2199
This paper presents the emissions results and operational behavior of two hybrid vehicles over EU legislative Real Driving Emissions (RDE) and other on-road testing cycles. The behavior of one hybrid vehicle during real world driving is investigated, including analyses of air-fuel ratio and catalyst temperature changes, in order to elucidate the reasons for the emissions results seen in the other hybrid vehicle over an RDE cycle. It was observed that the catalyst cooled down over time when the hybrid vehicle SI (Spark Ignition) engine was turned off, meaning that when the engine restarted the catalyst efficiency was decreased until it was able to light-off once again. This leads to increases in the tailpipe emissions of CO, NOx and hydrocarbons after the engine restarts. In addition to this problem, the engine restarts demanded fuel enrichment, which resulted in incomplete combustion and further increases in CO and PN emissions.
Technical Paper

Particle number emissions from standard and hybrid SI passenger cars

2019-12-19
2019-01-2194
This paper presents the PN (Particle Number) and some gaseous emissions results from a group of SI (Spark Ignition) passenger cars including HEV (Hybrid Electric Vehicle), PFI (Port Fuel Injection) and GDI (Gasoline Direction Injection) vehicles. The PEMS (Portable Emission Measurement System) was used for on-board emission measurements. The vehicles were driven using the routes complying with the EU Real Driving Emissions (RDE) test procedures required in the European Commission Regulation (EU) 2016/427, i.e. starting in an urban driving mode and then continuing into a rural driving mode and ending with motorway driving mode part. The percentage of these three segments is approximately 33%, 33%, 33% respectively. The total test time was between 90 to 120 minutes. The vehicles’ driving parameters such as road speed, tailpipe exhaust temperatures and energy consumption were recorded and their correlations with emissions were investigated.
Technical Paper

Real World Diesel Engine Greenhouse Gas Emissions for Diesel Fuel and B100

2013-04-08
2013-01-1514
The transport sector is one of the major contributors to greenhouse gas emissions. This study investigated three greenhouse gases emitted from road transport using a probe vehicle: CO₂, N₂O and CH₄ emissions as a function temperature. It should be highlighted that methane is a greenhouse gas that similarly to carbon dioxide contributes to global warming and climate change. An oxidation catalyst was used to investigate CO₂, N₂O and CH₄ GHG emissions over a real-world driving cycle that included urban congested traffic and extra-urban driving conditions. The results were determined under hot start conditions, but in congested traffic the catalyst cooled below its light-off temperature and this resulted in considerable N₂O emissions as the oxidation catalyst temperature was in the N₂O formation band. This showed higher N₂O during hot start than for diesel fuel and B100 were compared. The B100 fuel was Fatty Acid Methyl Ester (FAME), derived from waste cooking oil, which was mainly RME.
Journal Article

Influence of Cold Start and Ambient Temperatures on Greenhouse Gas (GHG) Emissions, Global Warming Potential (GWP) and Fuel Economy for SI Car Real World Driving

2010-04-12
2010-01-0477
The transport sector is one of the major contributors to greenhouse gas emissions. This study investigated three greenhouse gases emitted from road transport using a probe vehicle: CO₂, N₂O and CH₄ emissions as a function of cold start and ambient temperatures. A real-world driving cycle has been developed at Leeds and referred as LU-BS, which has an urban free flow driving pattern. The test vehicle was driven on the same route by the same driver on different days with different ambient temperatures. All the journeys were started from cold. An in-vehicle FTIR emission measurement system was installed on a EURO2 emission compliance SI car for emissions measurement at a rate of 0.5 Hz. This emission measurement system was calibrated on a standard CVS measurement system and showed an excellent agreement on the CO₂ measurement with the CVS results. The N₂O and CH₄ were calibrated by calibration gas bottles.
Journal Article

Effect of Multifunctional Fuel Additive Package on Fuel Injector Deposit, Combustion and Emissions using Pure Rape Seed Oil for a DI Diesel

2009-11-02
2009-01-2642
This work investigates the effect of a multifunctional diesel fuel additive package used with RapeSeed Oil (RSO) as a fuel in a DI heavy duty diesel engine. The effects on fuel injectors’ cleanliness were assessed. The aim was to maintain combustion performance and preventing the deterioration of exhaust emissions associated with injector deposit build up. Two scenarios were investigated: the effect of deposit clean-up by a high dose of the additive package; and the effect of deposit prevention using a moderate dose of the additive package. Engine combustion performance and emissions were compared for each case against use of RSO without any additive. The engine used was a 6 cylinder, turbocharged, intercooled Perkins Phaser Engine, fitted with an oxidation catalyst and meeting the Euro II emissions limits. The tests were conducted under steady state conditions of 23kW and 47kW power output at an engine speed of 1500 rpm.
Technical Paper

Investigation of Aldehyde and VOC Emissions during Cold Start and Hot Engine Operations using 100% Biofuels for a DI Engine

2009-04-20
2009-01-1515
Aldehydes and other Volatile Organic compounds (VOC) are assessed under cold start and steady state conditions using a Perkins Phaser 6 litre diesel engine. A comparison is made between petroleum diesel fuel (PD), 100% biodiesel (WME) and 100% rapeseed oil (RSO). A Temet FTIR was used to determine aldehydes including formaldehyde, acetaldehyde and acrolein. The diesel engine was cold started at room temperature using a step start up procedure that kept the power output constant at two steady state conditions: 23kW and 47kW. Very little difference was observed between petroleum diesel and biodiesel aldehyde emissions at either steady state conditions or during cold start. There was, however, an increase in aldehydes at steady state for rapeseed oil, particularly at low load, but only for from ∼10ppm to 25 ppm for formaldehyde (i.e. 0.12g/kWh to 0.37g/kWh). During cold start conditions, the emissions were significantly higher for rapeseed oil than for petroleum diesel.
Technical Paper

The Influence of Fuel Pre-Heating on Combustion and Emissions with 100% Rapeseed Oil for a DI Diesel Engine

2009-04-20
2009-01-0486
This work investigates the heating of unprocessed rapeseed oil as a means to improve fuel delivery by reducing the fuel viscosity, and to assess the effects on combustion performance. The results show that a simple low power heater with thermal insulation around the fuel line and pump can effectively raise the operational fuel temperature at delivery to the pump. The results show that even with a moderate temperature increase, the fuel flow limitations with rapeseed oil are reduced and the legislated gaseous emissions are reduced at steady state conditions. As one of the main reasons for the conversion of straight oils to the methyl ester, ie biodiesel, is to reduce the viscosity, this work shows that heating the oil can have a similar effect. An emissions benefit is observed with biodiesel compared to rapeseed oil but this is not large. There is also a significant greenhouse gas and cost benefit associated with straight vegetable oils.
Technical Paper

Comparison of Real World Emissions in Urban Driving for Euro 1-4 Vehicles Using a PEMS

2009-04-20
2009-01-0941
An on-board emission measurement system (PEMS), the Horiba OBS 1300, was installed in Euro 1-4 SI cars of the same model to investigate the impact of vehicle technology on exhaust emissions, under urban driving conditions with a fully warmed-up catalyst. A typical urban driving loop cycle was used with no traffic loading so that driver behavior without the influence of other traffic could be investigated. The results showed that under real world driving conditions the NOx emissions exceeded the legislated values and only at cruise was the NOx emissions below the legislated value. The higher NOx emissions during real-world driving have implications for higher urban Ozone formation. With the exception of the old EURO1 vehicle, HC and CO emissions were under control for all the vehicles, as these are dominated by cold start issues, which were not included in this investigation.
Technical Paper

Investigation of Regulated and Non-Regulated Cold Start Emissions using a EURO3 SI Car as a Probe Vehicle under Real World Urban Driving Conditions

2008-10-06
2008-01-2428
Regulated and non-regulated tailpipe exhaust emissions were measured under real world urban driving conditions using a set of in-vehicle FTIR emission measurement system, which is able to measure 65 emission components simultaneously at a rate of 0.5 Hz. A EURO3 emission compliant SI car was used as a probe vehicle. An urban driving cycle was used for the test and four repeated journeys were conducted. The results were compared to EU emissions legislation. The results show that the TWC needed approximately 200 seconds to reach full conversion efficiency. THC and NOx emissions exceeded the EURO 3 exhaust emission legislation. CO2 emissions were well above the type approval value of this type of the vehicle. Greenhouse gases (methane and nitrous oxide) and toxic hydrocarbons such as benzene were predominantly emitted during cold start period from 0 to 200 seconds of the engine start. The results had a reasonable repeatability for most of the emissions.
Technical Paper

Reduction of Exhaust Emissions by a Synthetic Lubricating Oil with Higher Viscosity Grade and Optimized Additive Package for a Heavy Duty DI Diesel Engine Test

2008-10-06
2008-01-2489
A 10W-50 G4 synthetic lubricating oil (EULUBE oil) was tested on a heavy duty DI diesel engine under two steady state conditions. The exhaust emissions were measured and compared to a 10W-30 CF semi-synthetic lubricating oil. The EULUBE oil contained the friction reduction additive to improve the fuel economy. The engine used was a 6 cylinder, turbocharged, intercooled Perkins Phaser Engine, with emission compliance of EURO 2, fitted with an oxidation catalyst. The exhaust samples were taken both upstream and downstream of the catalyst. Gaseous and particulates emissions were measured. Particulate size distribution was measured using ELPI and SMPS. The particulate samples were analysed for VOF, carbon and ash. A MEXA7100 gas analysis system was used for legislated gas analysis such as CO, CO2, NOx and total hydrocarbons. The results showed a significant reduction by synthetic lubricating oil in gaseous hydrocarbon emissions, total particulate mass, particulate carbon and ash.
Technical Paper

Characterization of Regulated and Unregulated Cold Start Emissions for Different Real World Urban Driving Cycles Using a SI Passenger Car

2008-06-23
2008-01-1648
An in-vehicle FTIR emission measurement system was used to investigate the exhaust emissions under different real world urban driving conditions. Five different driving cycles were developed based on real world urban driving conditions including urban free flow driving, junction maneuver, congested traffic and moderate speed cruising. The test vehicle was a EURO 2 emission compliant SI car equipped with temperature measurement along the exhaust pipe across the catalyst and real time fuel consumption measurement system. Both regulated and non-regulated emissions were measured and analyzed for different driving cycles. All journeys were started from cold. The engine warm up features and emissions as a function of engine warm up for different driving conditions were investigated.
Journal Article

Impact of Driving Cycles on Greenhouse Gas Emissions and Fuel Economy for SI Car Real World Driving

2008-06-23
2008-01-1749
The transport sector is one of the major contributors to greenhouse gas emissions. This study investigated three greenhouse gases emitted from road transport: CO2, N2O and CH4 emissions as a function of engine warm up and driving cycles. Five different urban driving cycles were developed and used including free flow driving and congested driving. An in-vehicle FTIR (Fourier Transform Inferred) emission measurement system was installed on a EURO2 emission compliant SI (Spark Ignition) car for emissions measurement at a rate of 0.5 HZ under real world urban driving conditions. This emission measurement system was calibrated on a standard CVS (Constant Volume Sampling) measurement system and showed excellent agreement on CO2 measurement with CVS results. The N2O and CH4 measurement was calibrated using calibration gas in lab. A MAX710 real time in-vehicle fuel consumption measurement system was installed in the test vehicle and real time fuel consumption was then obtained.
Technical Paper

Comparison of Exhaust Emissions and Particulate Size Distribution for Diesel, Biodiesel and Cooking Oil from a Heavy Duty DI Diesel Engine

2008-04-14
2008-01-0076
Rape oil, as used in fresh cooking oil (FCO), and the methyl ester derived from waste cooking oil (WCOB100) were tested as 100% biofuels (B100) on a heavy duty DI diesel engine under steady state conditions. The exhaust emissions were measured and compared to those for conventional low sulphur (<50ppm) diesel fuel. The engine used was a 6 cylinder, turbocharged, intercooled Perkins Euro2 Phaser Engine, fitted with an oxidation catalyst. The engine out gaseous emissions results for WCOB100 showed a large decrease in CO and HC emissions, but a small increase in NOx emissions compared to diesel. However, for FCO the CO and HC increased relative to WCOB100 and CO was higher than for diesel, indicating deterioration in fuel/air mixing. The particulate matter (PM) emissions for WCOB100 were similar to those for diesel at the 23kw condition, but greatly reduced at 47kw. The FCO produced higher engine out PM at both power conditions due to a higher volatile organic fraction (VOF).
Journal Article

Study of Thermal Characteristics and Emissions during Cold Start using an on-board Measuring Method for Modern SI Car Real World Urban Driving

2008-04-14
2008-01-1307
Exhaust emissions were measured under real world urban driving conditions using a set of in-vehicle FTIR emission measurement system, which is able to measure 65 emission components simultaneously at a rate of 0.5 Hz. The test vehicle was a modern EURO4 emission compliant SI car equipped with temperature measurement along the exhaust pipe across the catalyst so as to match thermal characteristics to emission profiles. A free flow urban driving cycle was used for the test and four repeated journeys were conducted. The results were compared to EU emissions legislation. The results show that the warm up of the lubricating oil needed 15 minutes. The TWC needed about 200 seconds to reach full conversion efficiency. CO, THC and NOx emissions exceeded the EURO4 exhaust emission legislation. CO2 emissions were well above the type approval value of this vehicle.
Journal Article

VOC Emissions and OFP Assessment for Two Real World Urban Driving Cycles using a EURO 2 SI Car

2008-04-14
2008-01-1303
A FTIR in-vehicle on-road emission measurement system was installed in a EURO2 emissions compliant SI (Spark Ignition) car to investigate exhaust Volatile Organic Compounds (VOC) emissions and Ozone Formation Potential (OFP) under different urban traffic conditions. The real time fuel consumption and vehicle traveling speed were measured and logged. The temperatures were measured along the exhaust pipe so as to monitor the thermal characteristics and efficiency of the catalyst. Two real world driving cycles were developed with different traffic conditions. One (West Park Loop cycle) was located in a quiet area with few traffic interference and the other one (Hyde Park Loop cycle) was in a busy area with more traffic variations. The test car was pre-warmed before each test to eliminate cold start effect. The driving parameters were analyzed for two real world cycles.
Technical Paper

Comparisons of the Exhaust Emissions for Different Generations of SI Cars under Real World Urban Driving Conditions

2008-04-14
2008-01-0754
EURO 1, 2 3 and 4 SI (Spark Ignition) Ford Mondeo passenger cars were compared for their real world cold start emissions using an on-board FTIR (Fourier Transform Infrared) exhaust emission measurement system. The FTIR system can measure up to 65 species including both regulated and non-regulated exhaust pollutants at a rate of 0.5 Hz. The driving parameters such as speed, fuel consumption and air/fuel ratio were logged. The coolant water, lube oil and exhaust temperatures were also recorded. A typical urban driving cycle including a loop and a section of straight road was used for the comparison test as it was similar to the legislative ECE15 urban driving cycle. Exhaust emissions were calculated for the whole journey average and compared to EU legislation. The cold start transient emissions were also investigated as a separate parameter and this was where there was the greatest difference between the four vehicles.
Technical Paper

Analysis of Driving Parameters and Emissions for Real World Urban Driving Cycles using an on-board Measurement Method for a EURO 2 SI car

2007-07-23
2007-01-2066
A FTIR in-vehicle on-road emission measurement system was installed in a EURO 2 emissions compliant SI car to investigate exhaust emissions under different urban traffic conditions. The real time fuel consumption and vehicle traveling speed was measured and logged. The temperatures were measured along the exhaust pipe so as to monitor the thermal characteristics and efficiency of the catalyst. Two real world driving cycles were developed with different traffic conditions. One (WP cycle) was located in a quiet area with few traffic interference and the other one (HPL cycle) was in a busy area with more traffic variations. The test car was pre-warmed before each test to eliminate cold start effect. The driving parameters were analyzed for two real world cycles. The WP cycle had higher acceleration rate, longer acceleration mode and shorter steady speed driving mode and thus harsher than the HPL cycle.
Technical Paper

The Use of a Water/Lube Oil Heat Exchanger and Enhanced Cooling Water Heating to Increase Water and Lube Oil Heating Rates in Passenger Cars for Reduced Fuel Consumption and CO2 Emissions During Cold Start.

2007-07-23
2007-01-2067
Lubricating oil takes all of the NEDC test cycle time to reach 90°C. Hence, this gives high friction losses throughout the test cycle, which leads to a significant increase in the fuel consumption. In real world driving, particularly in congested traffic, it is shown that lube oil warm-up is even slower than in the NEDC. Euro 1, 2 and 4 Ford Mondeo water and oil warm up rates in real world urban driving were determined and shown to be comparable with the results of Kunze et al. (2) for a BMW on the NEDC. This paper explores the use of forced convective heat exchange between the cooling water and the lube oil during the warm-up period. A technique of a step warm-up of the engine at 32 Nm at 2000 rpm (35% of peak power) was used and the engine lube oil and water temperature monitored. It was shown that the heat exchanger results in an increase in lube oil temperature by 4°C, which increased to 10°C if enhanced heat transfer to the water was used from an exhaust port heat exchanger.
Technical Paper

Study of thermal characteristics, fuel consumption and emissions during cold start using an on-board measuring method for SI car real world urban driving

2007-07-23
2007-01-2065
Exhaust emissions were measured under real world urban driving conditions using a set of in-vehicle FTIR emission measurement system, which is able to measure 65 emission components simultaneously at a rate of 0.5 Hz. The test vehicle was a EURO 2 emission compliant SI car equipped with real time fuel consumption measurement and temperature measurement along the exhaust pipe across the catalyst allowing the matching of thermal characteristics to emission profiles and monitor fuel consumption. The temperature profile indicated that the light-off of the catalyst took about 150∼200 seconds. The warm up of the lubricating oil and coolant water required a longer time than the catalyst did. The impact of ambient temperatures on lubricating oil and coolant water warm ups was greater than that on the light-off of the catalyst. The heat loss and energy balance were calculated during the whole cycle period. The influence of cold start on fuel consumption was investigated.
Technical Paper

Impact of Traffic Conditions and Road Geometry on Real World Urban Emissions Using a SI Car

2007-04-16
2007-01-0308
A precision in-vehicle tail-pipe emission measurement system was installed in a EURO1 emissions compliant SI car and used to investigate the variability in tail-pipe emission generation at an urban traffic junction and uphill/downhill road, and thereby the impact of road topography on emissions. Exhaust gas and skin temperatures were also measured along the exhaust pipe of the instrumented vehicle, so the thermal characteristics and the efficiency of the catalyst could be monitored. Different turning movements (driving events) at the priority T-junction were investigated such as straight, left and right turns with and without stops. The test car was run until hot stable operating conditions were achieved before each test, thereby negating cold start effects.
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