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Technical Paper

The Development of Driveability Index and the Effects of Gasoline Volatility on Engine Performance

1995-10-01
952521
To reduce engine exhaust emissions, we have had to deal with this global environmental problem from the fuel side by introducing oxygenated fuels, reducing the RVP and using low aromatics. But when we change the fuel components and distillation, we must take note about how these affect the engine driveability. We have used T50, T90, RVP and so on as the fuel index up to the present. It is possible to characterize the fuel from one aspect, but these indexes don't always represent the real feature of the fuel. In this paper we propose a New Driveability Index (here in after referred to as NDI) that is more realistic and accurate than the other fuel indexes. We used a 1600cc DOHC L4 MPI type engine. We used Model Gasolines and Market Gasolines, see Appendix(1), (2) and (3), and tested them according to the Excess Air Ratio Response Test Method (here in after referred to as λ-R Test) that was suggested in SAE paper #930375, and we calculated the NDI statistically.
Technical Paper

Extent of Oxidation of Hydrocarbons Desorbing from the Lubricant Oil Layer in Spark-ignition Engines

1996-02-01
960069
The extent of oxidation of hydrocarbons desorbing from the oil layer has been measured directly in a hydrogen-fueled, spark-ignited engine in which the lubricant oil was doped with a single component hydrocarbon. The amount of hydrocarbon desorbed and oxidized could be measured simultaneously as the dopant was only source of carbon-containing species. The fraction oxidized was strongly dependent on engine load, hydrogen fuel-air ratio and dopant chemical reactivity, but only modestly dependent on spark timing and nitrogen dilution levels below 20 percent. Fast FID measurements at the cylinder exit showed that the surviving hydrocarbons emerge late in the exhaust stroke.
Technical Paper

Auto-Oil Program Phase II Heavy Hydrocarbon Study: Analysis of Engine-Out Hydrocarbon Emissions Data

1994-10-01
941966
The engine-out (EO) total and speciated hydrocarbon emissions data from the Auto-Oil Program Phase II Heavy Hydrocarbon Study had been analyzed. The methodology was to first investigate the stabilized EO emissions (Bag 2) of a specific vehicle (Vehicle 04B, a 1989 Model Year Ford Taurus); then the vehicle-to-vehicle differences in Bag2 emissions were considered. Finally, the differences in the Bag2 and the starting/warm-up EO emissions (Bag1) were examined. The speciated emissions may be interpreted as a “feed-through” part due to the unreacted fuel species, and an “offset” part due to the decomposition products. The significant non-fuel emitted species were methane and the olefins. The HC emissions for vehicles with different total emissions were similar in species composition. For both the total and speciated emissions, there was no substantial difference between the Bag1 and Bag2 values for Vehicle 04B.
Technical Paper

Novel Experiment on In-Cylinder Desorption of Fuel from the Oil Layer

1994-10-01
941963
A technique has been developed to measure the desorption and subsequent oxidation of fuel in the oil layer by spiking the oil with liquid fuel and firing the engine on gaseous fuel or motoring with air. Experiments suggest that fuel desorption is not diffusion limited above 50 °C and indicated that approximately two to four percent of the cylinder oil layer is fresh oil from the sump. The increase in hydrocarbon emissions is of the order of 100 ppmC1 per 1% liquid fuel introduced into the fresh oil in a methane fired engine at mid-speed and light load conditions. Calculations indicate that fuel desorbing from oil is much more likely to produce hydrocarbon emissions than fuel emerging from crevices.
Technical Paper

Experimental Studies on a Natural Gas Vehicle

1994-10-01
942005
This paper presents the results of several studies conducted on a natural gas vehicle. In one study of engine-out emissions performance, the exhaust emissions of the CNG engine were lower than those of the base gasoline engine. In another study of the conversion characteristics of three-way catalysts, it was found that the conversion efficiency of total hydrocarbons (THCs) was much lower in the lean-mixture region for the NGV. The reduced efficiency was traced to lower conversion and poor reactivity of low-end hydrocarbons and to a higher concentration of H2O.
Technical Paper

Chemical Kinetic Modeling of the Oxidation of Unburned Hydrocarbons

1992-10-01
922235
The chemistry of unburned hydrocarbon oxidation in SI engine exhaust was modeled as a function of temperature and concentration of unburned gas for lean and rich mixtures. Detailed chemical kinetic mechanisms were used to model isothermal reactions of unburned fuel/air mixture in an environment of burned gases at atmospheric pressure. Simulations were performed using five pure fuels (methane, ethane, propane, n-butane and toluene) for which chemical kinetic mechanisms and steady state hydrocarbon (HC) emissions data were available. A correlation is seen between reaction rates and HC emissions for different fuels. Calculated relative amounts of intermediate oxidation products are shown to be consistent with experimental measurements.
Technical Paper

Effect of Catalyst Systems on Characteristics of Exhaust Hydrocarbon Species

1993-10-01
932718
The California Low-Emission Vehicle (LEV) standards mandate a reduction in non-methane organic gases (NMOG). With the aim of analyzing NMOG emissions, a comparison was made of the hydrocarbon species found in the exhaust gas when different types of catalyst systems and fuel specifications were used. NMOG emissions are usually measured by removing methane from the total hydrocarbon (THC) emissions and adding aldehyde and ketone emissions. The NMOG level found in this way is thus influenced by the rate of methane in THC emissions. Another important factor in the LEV standards is specific reactivity (SR), indicating the formation potential of ozone, which is one cause of photochemical smog. Specific reactivity is expressed by the amount of ozone generated per unit weight of NMOG emissions, and is affected by the respective proportion of hydrocarbon species in the total NMOG emissions.
Technical Paper

Autoignition of Alcohols and Ethers in a Rapid Compression Machine

1993-10-01
932755
The autoignition characteristics of methanol, ethanol and MTBE (methyl tert-butyl ether) have been investigated in a rapid compression machine at pressures in the range 20-40 atm and temperatures within 750-1000 K. All three oxygenated fuels tested show higher autoignition temperatures than paraffins, a trend consistent with the high octane number of these fuels. The autoignition delay time for methanol was slightly lower than predicted values using reported reaction mechanisms. However, the experimental and measured values for the activation energy are in very good agreement around 44 kcal/mol. The measured activation energy for ethanol autoignition is in good agreement with previous shock tube results (31 kcal/mol), although ignition times predicted by the shock tube correlation are a factor of three lower than the measured values. The measured activation energy for MTBE, 41.4 kcal/mol, was significantly higher than the value previously observed in shock tubes (28.1 kcal/mol).
Technical Paper

Flame Kernel Development in a Methanol Fueled Engine

1993-10-01
932649
The combustion behavior in a modem 4-valve engine using a broad range of methanol/gasoline fuel mixtures was studied. The initial flame development was examined by using a spark plug fiber optics probe. Approximately, the kernel expansion speed, Sg, is relatively unchanged from M0 to M40; jumps by ∼30% from M40 to M60; and then remains roughly constant from M60 to M100. Statistics of the IMEP indicate that at a lean idle condition the combustion rate and robustness correlate with Sg: a higher value of Sg gives better combustion. Thus M60-M100 fuels give better idle combustion behavior than the M0-M40 fuels.
Technical Paper

Performance and Exhaust Emissions of Nissan FFV NX Coupe

1992-02-01
920299
The FFVs under study operates on either M85 or M0 or any mixture of the two. Nissan has been actively conducting reseach and development on flexible fuel vehicles (FFVs) to explore the possibilities for long-range energy conservation and air quality improvement. The engine converted for use in these FFVs is a 1.6 liter, four-cylinder in-line powerplant, with dual overhead camshafts and four valves per cylinder. It employs the Nissan Variable valve timing Control System (NVCS). The fuel sensor for measuring the methanol concentration in the fuel has been improved both in terms of accuracy and durability. This paper describes the engine performance and exhaust emission levels (formaldehydes unburned methanol and HC emissions) obtained with both M85 and M0.
Technical Paper

Dual-Fuel Gasoline-Alcohol Engines for Heavy Duty Trucks: Lower Emissions, Flexible-Fuel Alternative to Diesel Engines

2018-04-03
2018-01-0888
Long-haul and other heavy-duty trucks, presently almost entirely powered by diesel fuel, face challenges meeting worldwide needs for greatly reducing nitrogen oxide (NOx) emissions. Dual-fuel gasoline-alcohol engines could potentially provide a means to cost-effectively meet this need at large scale in the relatively near term. They could also provide reductions in greenhouse gas emissions. These spark ignition (SI) flexible fuel engines can provide operation over a wide fuel range from mainly gasoline use to 100% alcohol use. The alcohol can be ethanol or methanol. Use of stoichiometric operation and a three-way catalytic converter can reduce NOx by around 90% relative to emissions from diesel engines with state of the art exhaust treatment.
Technical Paper

Real World Performance of an Onboard Gasoline/Ethanol Separation System to Enable Knock Suppression Using an Octane-On-Demand Fuel System

2018-04-03
2018-01-0879
Higher compression ratio and turbocharging, with engine downsizing can enable significant gains in fuel economy but require engine operating conditions that cause engine knock under high load. Engine knock can be avoided by supplying higher-octane fuel under such high load conditions. This study builds on previous MIT papers investigating Octane-On-Demand (OOD) to enable a higher efficiency, higher-boost higher compression-ratio engine. The high-octane fuel for OOD can be obtained through On-Board-Separation (OBS) of alcohol blended gasoline. Fuel from the primary fuel tank filled with commercially available gasoline that contains 10% by volume ethanol (E10) is separated by an organic membrane pervaporation process that produces a 30 to 90% ethanol fuel blend for use when high octane is needed. In addition to previous work, this paper combines modeling of the OBS system with passenger car and medium-duty truck fuel consumption and octane requirements for various driving cycles.
Technical Paper

Alcohol Fueled Heavy Duty Vehicles Using Clean, High Efficiency Engines

2010-10-25
2010-01-2199
Non-petroleum based liquid fuels are essential for reducing oil dependence and greenhouse gas generation. Increased substitution of alcohol fuel for petroleum based fuels could be achieved by 1) use in high efficiency spark ignition engines that are employed for heavy duty as well as light duty operation and 2) use of methanol as well as ethanol. Methanol is the liquid fuel that is most efficiently produced from thermo-chemical gasification of coal, natural gas, waste or biomass. Ethanol can also be produced by this process but at lower efficiency and higher cost. Coal derived methanol is in limited initial use as a transportation fuel in China. Methanol could potentially be produced from natural gas at an economically competitive fuel costs, and with essentially the same greenhouse gas impact as gasoline. Waste derived methanol could also be an affordable low carbon fuel.
Technical Paper

Using Mass Spectrometry to Detect Ethanol and Acetaldehyde Emissions from a Direct Injection Spark Ignition Engine Operating on Ethanol/Gasoline Blends

2011-04-12
2011-01-1159
Ethanol and acetaldehyde emissions from a direct ignition spark ignition were measured using mass spectrometry. Previous methods focused on eliminating or minimizing interference from exhaust species with identical atomic mass and fragment ions created in ionization process. This paper describes a new technique which exploits the fragment ions from ethanol and acetaldehyde. A survey of mass spectra of all major species of exhaust gas was conducted. It was found that ethanol contributes most ions in mass number 31 and that no other gas species produces ions at this mass number. Acetaldehyde detection suffers more interference. Nevertheless, it was estimated that detection at mass number 43 is possible with 10% error from 2-methylbutane. This new technique was validated in an engine experiment. By running the engine with pure gasoline and E85, the validity of the technique can be checked.
Technical Paper

Impact Study of High Biodiesel Blends on Exhaust Emissions to Advanced Aftertreatment Systems

2010-04-12
2010-01-1292
In Biodiesel Fuel Research Working Group(WG) of Japan Auto-Oil Program(JATOP), some impacts of high biodiesel blends have been investigated from the viewpoints of fuel properties, stability, emissions, exhaust aftertreatment systems, cold driveability, mixing in engine oils, durability/reliability and so on. In the impact on exhaust emissions, the impact of high biodiesel blends into diesel fuel on diesel emissions was evaluated. The wide variety of biodiesel blendstock, which included not only some kinds of fatty acid methyl esters(FAME) but also hydrofined biodiesel(HBD) and Fischer-Tropsch diesel fuel(FTD), were selected to evaluate. The main blend level evaluated was 5, 10 and 20% and the higher blend level over 20% was also evaluated in some tests. The main advanced technologies for exhaust aftertreatment systems were diesel particulate filter(DPF), Urea selective catalytic reduction (Urea-SCR) and the combination of DPF and NOx storage reduction catalyst(NSR).
Technical Paper

Impact Study of High Biodiesel Blends on Performance of Exhaust Aftertreatment Systems

2008-10-06
2008-01-2494
Biodiesel Fuel (BDF) Research Work Group works on identifying technological issues on the use of high biodiesel blends (over 5 mass%) in conventional diesel vehicles under the Japan Auto-Oil Program started in 2007. The Work Group conducts an analytical study on the issues to develop measures to be taken by fuel products and vehicle manufacturers, and to produce new technological findings that could contribute to the study of its introduction in Japan, including establishment of a national fuel quality standard covering high biodiesel blends. For evaluation of the impacts of high biodiesel blends on performance of diesel particulate filter system, a wide variety of biodiesel blendstocks were prepared, ranging from some kinds of fatty acid methyl esters (FAME) to another type of BDF such as hydrotreated biodiesel (HBD). Evaluation was mainly conducted on blend levels of 20% and 50%, but also conducted on 10% blends and neat FAME in some tests.
Technical Paper

A New Approach to Ethanol Utilization: High Efficiency and Low NOx in an Engine Operating on Simulated Reformed Ethanol

2008-10-06
2008-01-2415
The use of hydrogen as a fuel supplement for lean-burn engines at higher compression ratios has been studied extensively in recent years, with good promise of performance and efficiency gains. With the advances in reformer technology, the use of a gaseous fuel stock, comprising of substantially higher fractions of hydrogen and other flammable reformate species, could provide additional improvements. This paper presents the performance and emission characteristics of a gas mixture of equal volumes of hydrogen, CO, and methane. It has recently been reported that this gas mixture can be produced by reforming of ethanol at comparatively low temperature, around 300C. Experiments were performed on a 1.8-liter passenger-car Nissan engine modified for single-cylinder operation. Special pistons were made so that compression ratios ranging from CR= 9.5 to 17 could be used. The lean limit was extended beyond twice stoichiometric (up to lambda=2.2).
Technical Paper

Low-cost FC Stack Concept with Increased Power Density and Simplified Configuration: Utilizing an Advanced MEA with Integrated Molded Frame

2011-05-17
2011-39-7260
In 2006, Nissan began limited leasing of the X-TRAIL FCV equipped with their in-house developed Fuel Cell (FC) stack. Since then, the FC stack has been improved in durability, cold start-up capability, cost and size with the aim of promoting full-scale commercialization of FCVs. However, reduction of cost and size has remained a significant challenge because limited mass transport through the membrane electrode assembly (MEA) has made it difficult to increase the rated current density of the FC. Furthermore, it has been difficult to reduce the variety of FC stack components due to the complex stack configuration. In this study, improvements have been achieved mainly by adopting an advanced MEA to overcome these difficulties. First, the adoption of a new MEA and separators has improved mass transport through the MEA for increased rated current density. Second, an integrated molded frame (IMF) has been adopted as the MEA support.
Technical Paper

Fuel Effects on HCCI Operation in a Spark Assisted Direct Injection Gasoline Engine

2011-08-30
2011-01-1763
The fuel effects on HCCI operation in a spark assisted direct injection gasoline engine are assessed. The low load limit has been extended with a pilot fuel injection during the negative valve overlap (NVO) period. The fuel matrix consists of hydrocarbon fuels and various ethanol blends and a butanol blend, plus fuels with added ignition improvers. The hydrocarbon fuels and the butanol blend do not significantly alter the high or the low limits of operation. The HCCI operation appears to be controlled more by the thermal environment than by the fuel properties. For E85, the engine behavior depends on the extent that the heat release from the pilot injected fuel in the NVO period compensates for the evaporative cooling of the fuel.
Technical Paper

Development of an On-Board Fuel Reforming Catalyst for a Gasoline Engine

2015-09-01
2015-01-1955
On-board hydrogen generation technology using a fuel reforming catalyst is an effective way to improve the fuel efficiency of automotive internal combustion engines. The main issue to be addressed in developing such a catalyst is to suppress catalyst deterioration caused by carbon deposition on the catalyst surface due to sulfur adsorption. Enhancing the hydrocarbon and water activation capabilities of the catalyst is important in improving catalyst durability. It was found that the use of a rare earth element is effective in improving the water activation capability of the catalyst. Controlling the hydrocarbon activation capability of the catalyst for a good balance with water activation was also found to be effective in improving catalyst durability.
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