Engine Test Cycle Research Articles

Development and demonstration of strategies for GHG and methane slip reduction from dual-fuel natural gas coastal vessels

Low Pressure Dual Fuel (LPDF) marine engines fueled with natural gas (NG) provide a cost-effective means for minimizing fuel sulfur content, and NOx and PM emissions for marine vessels. In addition, the use of NG can provide significant GHG reductions, if CH4 slip is mitigated. Alternative fueling strategies such as LPDF, are commonly assessed by life-cycle analyses using exhaust emission rates from generalized engine test cycles (e.g. IMO E2). As CH4 slip from LPDF NG engines is particularly sensitive to engine load, a greenhouse gas emission inventory based on generalized engine cycles may not accurately represent real-world vessel operation and emissions. The objectives of this work are to: (i) quantify the GHG emissions reductions possible using the current best available LPDF technology and, (ii) evaluate the attained real-world emissions reduction as a result of improved vessel operating strategies and state of the art engine technology for coastal LPDF vessels.Steady-state emission factors (g/kW-h) and emission rates (g/h) of CH4, CO, CO2, and NOx were measured during steady-state and dynamic operation for two roll-on-roll-off ferries with LPDF engines from two different manufacturers. During commercial operation, the combination of a revised LPDF engine calibration and best vessel operating strategy reduced GHG emissions by 57% and 24%, relative to stock LPDF and diesel operation on vessel #1, respectively. Compared to diesel operation, the annual GHG savings on vessel #1 as a result of this program equate to approximately 2.4 kT CO2e. The tank-to-wake CH4 emissions measured in the current and previous works were found to have poor agreement with the those based on the corresponding test cycle (E2). The E2 cycle overestimated the current CH4 emissions by 8–30% depending on the implemented operating strategy. Prior to implementation of these strategies, the E2 cycle underestimated the CH4 emissions by 74% (Peng et al., 2020). This underscores the value of in-use emission measurements for accurate evaluation of alternative fueling strategies, as well as the utility of emission-informed vessel operation strategies.

Synthesis of 5-(Hydroxymethyl)furfural Monoesters and Alcohols as Fuel Additives toward Their Performance and Combustion Characteristics in Compression Ignition Engines.

The synthesis of 5-(hydroxymethyl)furfural (HMF) and conversion to the corresponding HMF-monoesters upon certain treatment are presented with their properties that are validated in a diesel engine. With a collection of fatty acids (C8-C18) using cyanuric acid as a catalyst under mild reaction conditions, the subsequent reduction of the HMF-monoesters with NaBH4 produced the corresponding alcohols. After purification, both HMF-monoesters and their alcohol derivatives were determined for their solubility, cetane index, heat of combustion, viscosity, and specific gravity. HMF-Capric (1-C10), HMF-Oleic (1-C18:1), HMF-Caprylic-OH (2-C8), and HMF-Oleic-OH (2-C18:1) were soluble in a neat diesel fuel. The observed highest cetane index and heat of combustion of 1-C10 and 1-C18:1 were evaluated for combustion characteristics in a single-cylinder compression ignition engine. The diesel fuel containing 3% 1-C10 displayed comparable properties during burning in terms of thermal efficiency, cylinder pressure, and heat release rate with respect to the neat diesel fuel (D100) for all usage engine speeds. In general, all tested fuels initiated their burning onset with a similar ignition delay period. The 3% 1-C10-blended diesel fuel emitted slightly higher smoke opacity but an equivalent nitric oxide level compared to those of D100. The HMF-Capric (1-C10) synthesized in this study represents a promising additive for diesel fuel. Blended fuel lubricity and other unregulated emissions upon broader engine test cycles are suggested to be accomplished in future work.

Investigation of methods for measuring fuel economy and emissions of heavy-duty hybrid-electric vehicles (HEVs)

Hybrid-electric vehicles can achieve low fuel consumption and emission by optimal combination of electrical energy and internal combustion engine power. There are four main test method of energy consumption and emission for heavy-duty HEVs, including traditional engine bench test, powertrain test, HILS and chassis dynamometer test. The tradition engine operating conditions are distinguished from that in HEVs, which can’t reflect the performance of HEVs. Powertrain test can achieve braking energy regeneration, but need bulky installation on testbed. HILS test solves the problem that the engine test cycle is different from the actual operating condition on road and is cost-effective. However, it requires a lot of effort to monitor the HILS simulation input parameters and carry out vehicle validation. Chassis dynamometer test method can better reflect the real-road driving condition. But it is nearly impossible to test all different HEVs types on chassis dynamometer and the test cost is very expensive. By comparing different heavy-duty HEVs energy consumption and emission test methods, the advantages and disadvantages are identified, which provides guidance for the formulation of the next-stage standards of heavy-duty HEV, and promotes the healthy and orderly development of the HEV industry.

Analysis of Biodiesel Influence on Unregulated Gaseous Emissions of Diesel Motor Vehicles

This scientific study is focused on the analysis of an influence of the experimental diesel fuel mixtures containing various portions of the biocomponent on the unregulated gaseous emissions generated by a diesel motor vehicle, which is equipped with the diesel engine utilizing the direct fuel injection system “common rail”. The main reason for the choice of this engine type was its wide usage in the current vehicles. The experimental diesel fuel mixtures were created as a mixture of the standard low-sulfur diesel fuel with the biodiesel, using various mixing ratios. The experiments were realized by means of a special 13-regime engine test cycle, which was intentionally developed for the diesel combustion engines. All the individual experiments were performed on the base of the given test cycle with 13 different operational modes. The obtained results offer a complex view on the generation of the unregulated emissions with regard to the operational conditions and taking into consideration operational loading of the given experimental engine.

Analysis of the engine test cycles from China VI heavy duty vehicle standard and China automotive test cycle

This paper studied the engine test cycles including world harmonized steady cycle (WHSC), world harmonized transient cycle (WHTC) , china heavy-duty steady cycle (CHSC) and china heavy-duty transient cycle (CHTC) based on a diesel engine which meet the China VI heavy duty vehicle emission standard. The results show that regression analysis of speed, torque and power all meet the requirements of the China VI heavy duty vehicle standard. For this engine, NOx, PM and THC pollutants under CHSC are 134.5%, 29.6% and 94.4% higher than those under WHSC, respectively. PN emissions of CHSC is 65.6% lower than that of WHSC. NOx, PM and PN pollutants under CHTC are 62.9%, 96.4% and 64.3% higher than those under WHTC, respectively. The exhaust temperature of the first 350 seconds at CHTC is lower, which poses a greater challenge to the conversion efficiency of the after-treatment system at low speed and low load.

Technical research on engine cycle constructing based on transformation model

This paper presents a technical method to derive engine test cycle by establishing a vehicle-to-engine cycle transform model ; Firstly, input, process and transform vehicle cycle and test vehicle data to get corresponding engine condition; Then, apply model built-in gear use strategy to select gear; Finally, under the selected gear, transform vehicle cycle into engine cycle termed by normalized speed and load. In addition, Comparison between model output cycle and WHTC cycle demonstrates that this transform method features consistency with present emission test standard, adaptability to various engine technologies and representative of real-life test scenarios.

Numerical Investigation of SCR Mixer Design Optimization for Improved Performance

The continuous increase in the number of stringent exhaust emission legislations of marine Diesel engines had led to a decrease in NOx emissions at the required level. Selective catalyst reduction (SCR) is the most prominent and mature technology used to reduce NOx emissions. However, to obtain maximum NOx removal with minimum ammonia slip remains a challenge. Therefore, new mixers are designed in order to obtain the maximum SCR efficiency. This paper reports performance parameters such as uniformity of velocity, ammonia uniformity distribution, and temperature distribution. Also, a numerical model is developed to investigate the interaction of urea droplet with exhaust gas and its effects by using line (LM) and swirl (SM) type mixers alone and in combination (LSM). The urea droplet residence time and its interaction in straight pipe are also investigated. Model calculations proved the improvement in velocity uniformity, distribution of ammonia uniformity, and temperature distribution for LSM. Prominent enhancement in the evaporation rate was also achieved by using LSM, which may be due to the breaking of urea droplets into droplets of smaller diameter. Therefore, the SCR system accomplished higher urea conversion efficiency by using LSM. Lastly, the ISO 8178 standard engine test cycle E3 was used to verify the simulation results. It has been observed that the average weighted value of NOx emission obtained at SCR outlet using LSM was 2.44 g/kWh, which strongly meets International Maritime Organization (IMO) Tier III NOx (3.4 g/kWh) emission regulations.

An efficient reduced model of NH3-SCR converters for mobile aftertreatment systems

We derive reduced models (RM) of NH3-SCR automotive converters as a strategy to provide accurate simulations with minimized computational costs, in view of applications to the rapid calibration of SCR kinetics and to on-board control of the engine after-treatment systems. In the first part of this work, a reduced model of SCR monolithic catalysts is developed. To decrease the computational effort, a combination of explicit Euler methods for ODEs integration in time and backwards finite differences for discretization of space derivatives is implemented, adopting a simplified approach to calculate the region of stability of the explicit method. In the second part, we compare the reduced model with a reference, fully detailed SCR monolith converter model in terms of accuracy and computational costs for different engine test cycles, comprising cold start transients, for both light- and heavy-duty diesel engines. The tests demonstrate a decrease in the computational time for RM with respect to the reference full model by one to two orders of magnitude, while retaining a comparable accuracy.

Composition of carbonaceous fine particulate emissions of a flexible fuel DISI engine under high velocity and municipal conditions

A study about the chemical composition of carbonaceous fine particulate emissions of flexible fuel direct injection spark ignition engine under high velocity and municipal conditions was conducted with two different gasoline-ethanol blended fuels (E10 and E85). A self-designed engine test cycle simulating high vehicle velocity conditions of up to of 180 km/h was introduced (high velocity driving cycle, HVDC), simulating a possible motorway scenario without speed legislations as allowed in Germany, and compared to a municipal driving cycle (MDC), which is derived from the New European Driving Cycle (NEDC). The fingerprint of polycyclic aromatic hydrocarbons (PAHs) and their alkylated and oxygenated derivatives as well as the concentrations for PM2.5, elemental carbon (EC), organic carbon (OC) and also for the three most abundant PAHs were determined using a modified thermal optical carbon analyser (TOCA) hyphenated to soft resonance-enhanced multi-photon ionisation mass spectrometry (REMPI-TOFMS). Driving under high velocity conditions resulted in a significant increase of concentrations for PM, EC, OC, methyl-phenanthrenes and pyrene. Engine operation on E85 led to a strong decrease for all concentrations for both cycles. A good correlation was found between concentrations obtained by REMPI-TOFMS and TD-GC/MS. Most prominent PAHs were the alkylated series of phenanthrene, pyrene and naphthalene, whereby the abundances decrease with increasing degree of alkylation. The organic composition between HVDC and MDC mainly differed in quantity and to a lower extent in the aromatic pattern. Nevertheless, methyl-phenanthrenes, pyrene and methyl-pyrenes as well as 4H-cyclopenta[def]phenanthrene and benzo[b]naphtho[1,2-d]furan/benzo[b]naphtho[2,3-d]furan and it alkylated series showed a higher abundance in the pattern under high velocity conditions, where alkylated naphthalenes were enhanced in the MDC mode.

Emissions Certification Vehicle Cycles Based on Heavy Duty Engine Test Cycles

Emissions Certification Vehicle Cycles Based on Heavy Duty Engine Test Cycles

Development of a Heavy-Duty Engine Test Cycle Representative of On-Highway Not-To-Exceed Operation

This paper describes the development of an engine test cycle that is representative of the real-world heavy-duty engine activity in the not-to-exceed (NTE) zone of operation. The test cycle is intended to provide an in-laboratory verification capability to determine if an engine exceeds the in-use emissions standards. By simulating the real-world driving pattern of the vehicle the test cycles provide the most realistic estimation of emission levels in the NTE zone of operation. It is well recognized that traditional laboratory test cycles do not provide an accurate representation of a vehicle's operation on the road under present-day driving conditions. This cycle was developed by collecting and analysing engine activity data and statistical information on heavy-duty vehicle use for different applications under real-world conditions. A test vehicle instrumented with the West Virginia University mobile emissions measurement system (MEMS), a portable on-board tailpipe exhaust emissions measurement system, was used to obtain engine operating conditions, vehicle speed, and in-use brake-specific emissions of CO2 and NO x. The vehicle was tested on specific routes, which included a mix of highway and city driving patterns. The speed and torque points were normalized according to procedures described in the Code of Federal Regulations (CFR) Title 40, Part 1065. A representative transient cycle that was developed has been used to conduct emissions tests on heavy-duty diesel engines, and serves to characterize NO x emissions during the NTE operation. This characterization will aid in-laboratory testing and provide a better understanding of the emissions behaviour during on-road NTE operation, electronic control module calibrations, and engine development. The results indicate that the on-highway NTE cycle called the ‘WVU NTE cycle’ produced emissions results that were within ±1 per cent of those produced during an on-road test.

Analysis of particulate matter composition from a heavy-duty diesel engine

In order to control particulate matter (PM) in the exhaust of diesel-powered automobiles, a better understanding of the components of PM is required. In this report, the ECE R49 13-mode engine test cycle was performed on a heavy-duty diesel engine. Unlike the usual ECE R49 13-mode sample method, PM in the exhaust was separately sampled in this research under every test mode. Oxides of nitrogen (NOx) in the exhaust were also measured. Soluble organic fraction (SOF) and insoluble fraction (ISF) of the PM were partitioned with an ultrasonic elution, and then every SOF sample was analysed by combined gas chromatography / mass spectrometry (GC / MS). The results show that the mass flux of PM increases with increasing engine loads, and there is an exponential growth function between the PM mass flux and the engine power under the same engine speed. Concerning the engine's NOx emissions, there is an exponential decay function between the concentration of NOx and engine power. By comparing the results obtained, the effects of load and speed on the contents of ISF and SOF in PM were observed. The percentages of ISF and SOF contents in PM are markedly changed with the load, but are less influenced by the speed at the same percentage of load. The dominant component in SOF is paraffin hydrocarbon and second is polycyclic aromatic hydrocarbon (PAH). The percentage of PAH content in PM is higher at lower loads. In addition, naphthalene and phenanthrene are the main organic components of PAH.

Characterisation of an urban bus network for environmental purposes

Since pollutant emissions are closely related to the operating conditions of vehicles, their evaluation usually involves studying these operating conditions (through bus instrumentation and monitoring under actual operation), the design of representative driving or engine test cycles and the measurement of pollutant emissions. A preliminary characterisation of the routes on a bus network should make it possible to identify typical routes, the driving conditions and pollutant emissions of which are then studied. Two approaches are envisaged and applied to the Paris area, for which a wealth of information is available, which should be transferable to other bus networks. Both approaches are based on factorial analysis and automatic clustering, to allow optimum description and the identification of a pertinent typology of the bus routes in several classes. The first attempt at characterisation is based on statistics relating to bus operations: route characteristics (length, dedicated bus lanes, number of stops, location of stops: schools, tourist sites, hospitals, railways or underground stations), travel time, commercial speed, annual statistics (number of passengers, number of vehicles per hour, total kilometres), the irregularity of travel (variation of travel times, injuries, congestion.), as well as information on the problems encountered (congestion, distribution of the passenger load, junctions, bends). A second approach is based on the analysis of the “urban context” in which buses are driven. Population, employment, housing, road network, traffic and places that generate or disturb traffic (schools, railway stations, shopping areas, etc.) are calculated for the Ile de France region, by cells of 100×100 m, and collected in a geographical information system (GIS). Statistical analyses enable a typology of these urban cells to be established, the main parameters being density, type of housing, road types and traffic levels. The bus routes are then analysed according to their itineraries across these typical areas (distances travelled in each type of area) using a similar approach. A comparison of the typologies obtained from operational data and from urban data highlights the advantages and disadvantages of the two approaches. The first result from these typologies is the selection of routes which are representative of the different classes, in order to instrument buses and record driving patterns. This method should also make it possible to link driving conditions and urban characteristics, and then to allocate pollutant emission factors to given geographical situations, in particular, in the context of emission inventories or impact studies.

Analysis of the Combustion Process in a EURO III Heavy-Duty Direct Injection Diesel Engine

To fulfill the commitments of future pollutant regulations, current development of direct injection (DI) Diesel engines requires to improve knowledge on the injection/combustion process and the effect of the injection parameters and engine operation conditions upon the spray and flame characteristics and how they affect engine performance and pollutant emissions. In order to improve comprehension of the phenomena inherent to Diesel combustion, a deep experimental study has been performed in a single-cylinder engine with the main characteristics of a six-cylinder engine passing the EURO III legislation. Some representative points of the 13-mode engine test cycle have been considered modifying the nominal values of injection pressure, injection load, intake pressure, engine speed, and injection timing. The study combines performance and emissions experimental measurements together with heat release law (HRL) analysis and high-speed visualization. Controlling parameters for BSFC, NOx, and soot emissions are identified in the last part of the paper.

Type performance of Fischer—Tropsch liquids in modified off-highway diesel engine test cycle

Type performance of Fischer—Tropsch liquids in modified off-highway diesel engine test cycle

Mutagenic and cytotoxic effects of exhaust particulate matter of biodiesel compared to fossil diesel fuel

The mutagenic and cytotoxic effects of diesel engine exhaust (DEE) from a modern passenger car using rapeseed oil methyl esters (RME, biodiesel) as fuel were directly compared to DEE of diesel fuel (DF) derived from petroleum. Combustion particulate matter was collected on glass fiber filters coated with polytetrafluoroethylene (PTFE) from an exhaust dilution tunnel using three different engine test cycles on a chassis dynamometer. Filters were extracted with dichloromethane in a soxhlet apparatus for 12 h. The mutagenicity of the extracts was tested in the Salmonella typhimurium/mammalian microsome plate-incorporation assay using strains TA97a, TA98, TA100, and TA102. The toxicity to the established cell line L929 (mouse lung fibroblasts) was investigated in the neutral red assay. In the tester strains TA98 and TA100 a significant increase of mutations resulted for the particle extracts of both fuels, but for DF the revertants were significantly higher compared to RME. The highest levels of revertants were observed in tests including a cold start phase. This was probably due to incomplete combustion in the cold engine and a lower conversion rate of the cold catalytic converter. Testing with activated liver S9 fraction induced a slightly lower increase of revertants in most experiments. TA97a and TA102 showed no significant enhancement of spontaneous mutations. In the FTP-75 test cycle RME extracts showed slightly higher toxic effects to the L929 cells than DF, whereas in the other tests no significant differences were observable. These results indicate a higher mutagenic potency of DEE of DF compared to RME. This is probably due to the lower content of polycyclic aromatic compounds (PAC) in RME exhaust, although the emitted masses of RME were higher in most test procedures applied in this study.

Heavy-duty engine exhaust emission tests using methyl ester soybean oil/diesel fuel blends

A model 6V92TA Detroit Diesel Corporation diesel engine (9.0 l) was fueled on blends of 10, 20, 30 and 40% soydiesel/diesel fuel. The engine was tested using the Environmental Protection Agency (EPA) heavy-duty engine test cycle in an EPA certification test cell. A 56.6 m 3/min (2000 cfm) PDP-CVS dilution tunnel, gaseous bench and particulate bench provided full gaseous and particulate emissions data. Fueling with biodiesel/diesel fuel blends reduced particulate matter (PM), total hydrocarbons (THC) and carbon monoxide (CO), while increasing oxides of nitrogen (NO x). The optimum blend of biodiesel and diesel fuel was a 20/80 biodiesel/diesel fuel blend. Retarded fuel injection timing reduced NO x emissions, while CO, THC and PM remained essentially constant with a 20/80 biodiesel/diesel fuel blend.

Application of Methods for Determining Total Organic Contribution to Diesel Particulates

This paper describes the laboratory effort to relate quantities of diesel particulate volatile organics obtained by DFI/GC™ to those obtained by traditional methods of organic analysis. Experiments were designed to investigate the potential usefulness of DFI/GC for determining the organic fraction and unburned lubricating oil contributions of diesel particulate emissions for future technology engines. A 1991 Caterpillar 3176 was used to generate samples during several heavy-duty engine test cycles, including the cold- and hot-start transient FTP and several steady-state conditions. Particulate-laden filter samples were then analyzed for organics by DFI/GC, solvent extraction, and vacuum volatilization. Results obtained using the three techniques were compared using statistical analysis techniques. Results showed that DFI/GC is extremely useful for directly determining the organic fraction of diesel particulate, and provides a better estimation of unburned lubricating oil contribution to the organic fraction than the other methods evaluated.

Measurement of exhaust emissions in piston and diesel engines by dispersive spectroscopy.

A versatile but simple, reliable, rugged, and compact vehicle exhaust monitoring system has been developed, allowing detection of carbon monoxide (CO), carbon dioxide (COo), high and low hydrocarbons (HHC and LHC), and nitric oxide (NO). The analysis is performed by dispersive absorption spectroscopy with instrumentation designed and fabricated for this demanding industrial environment. The operation of the instrumentation is described here, as well as results for both diesel and piston engine emission testing. This equipment has been used for California 7 mode-7 cycle hot start and cold start tests, the California heavy-duty engine test cycles, EPA CVS tests reading bag samples and also continuous dilute, and finally it has been used for idle checks. Testing has been performed on production automobiles, as well as those equipped with thermal reactors or catalytic mufflers, and also both heavy-duty gasoline and diesel. engines. The instrumentation has shown very good correlation with other established tec...