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Technical Paper

Validity of Low Ventilation for Accident Processing with Hydrogen Leakage from Hydrogen-Fuelled Vehicle

Appropriate emergency response information is required for first responder before hydrogen fuel cell vehicles will become widespread. This paper investigates experimentally the hydrogen dispersion in the vicinity of a vehicle which accidentally releases hydrogen horizontally with a single volumetric flow of 2000 NL/min in the under-floor section while varying cross and frontal wind effects. This hydrogen flow rate represents normally a full throttle power condition. Forced wind was about maximum 2 m/s. The results indicated that the windward side of the vehicle was safe but that there were chiefly two areas posing risks of fire by hydrogen ignition. One was the leeward side of the vehicle's underbody where a larger region of flammable hydrogen dispersion existed in light wind than in windless conditions. The other was the area around the hydrogen leakage point where most of the leaked hydrogen remained undiffused in an environment with a wind of no stronger than 2 m/s.
Journal Article

Validation of the Localized Fire Test Method for On-Board Hydrogen Storage Systems

The localized fire test provided in the Global Technical Regulation for Hydrogen Fuel Cell Vehicles gives two separate test methods: the ‘generic installation test - Method 1′ and the ‘specific vehicle installation test - Method 2′. Vehicle manufacturers are required to apply either of the two methods. Focused on Method 2, the present study was conducted to determine the characteristics and validity of Method 2. Test results under identical burner flame temperature conditions and the effects of cylinder protection covers made of different materials were compared between Method 1 and Method 2.
Technical Paper

Unregulated Emissions Evaluation of Gasoline Combustion Systems (Lean Burn / Stoichiometric DISI and MPI), State of the Art Diesel Aftertreatment Technologies (DPF, urea-SCR and DOC), and Fuel Qualities Effects (EtOH, ETBE, Aromatics and FAME)

In order to clarify future automobile technologies and fuel qualities to improve air quality, second phase of Japan Clean Air Program (JCAPII) had been conducted from 2002 to 2007. Predicting improvement in air quality that might be attained by introducing new emission control technologies and determining fuel qualities required for the technologies is one of the main issues of this program. Unregulated material WG of JCAPII had studied unregulated emissions from gasoline and diesel engines. Eight gaseous hydrocarbons (HC), four Aldehydes and three polycyclic aromatic hydrocarbons (PAHs) were evaluated as unregulated emissions. Specifically, emissions of the following components were measured: 1,3-Butadiene, Benzene, Toluene, Xylene, Ethylbenzene, 1,3,5-Trimethyl-benzene, n-Hexane, Styrene as gaseous HCs, Formaldehyde, Acetaldehyde, Acrolein, Benzaldehyde as Aldehydes, and Benzo(a)pyrene, Benzo(b)fluoranthene, Benzo(k)fluoranthene as PAHs.
Technical Paper

Thermal Behavior in Hydrogen Storage Tank for FCV on Fast Filling (2nd Report)

If a compressed hydrogen tank for vehicles is filled with hydrogen gas more quickly, the gas temperature in the tank will increase. In this study, we conducted hydrogen gas filling tests using the TYPE 3 and TYPE 4 tanks. During the tests, we measured the temperature of the internal liner surface and investigated its relationship with the gas temperature in the tank. We found that the gas temperature in the upper portion of the TYPE 4 tank rose locally during filling and that the temperature of the internal liner surface near that area also rose, resulting in a temperature higher than the gas temperature at the center of the tank. To keep the maximum temperature in the tank below the designed temperature (85°C) during filling and examine the representative tank internal temperatures, it is important to examine filling methods that can suppress local rises of tank internal temperature.
Technical Paper

Test of Vehicle Ignition Due to Hydrogen Gas Leakage

The distribution of concentrations of hydrogen leaking into the front compartment and the dispersion after the leak was stopped were investigated to obtain basic data for specifying the mounting positions of hydrogen leak detecting sensors and the threshold values of alarms for compressed hydrogen vehicles. Ignition tests were also conducted to investigate the flammability and the environmental impact (i.e. the impact on human bodies). These tests were also conducted with methane to evaluate the protection against hydrogen leaks in vehicles in comparison with natural gas (methane). We found that the concentration of hydrogen in the front compartment reached 23.7 vol% maximum when hydrogen gas was allowed to leak for 600 sec from the center of the bottom of the wheelbase at a rate of 131 NL/min, which is the allowable limit for a fuel leak at the time of collision of compressed hydrogen vehicles in Japan.
Technical Paper

Summary report of Japan Clean Air Program diesel and diesel fuel activities

Diesel emissions are significant issue worldwide, and emissions requirements have become so tough that. the application of after-treatment systems is now indispensable in many countries To meet even more stringent future emissions requirements, it has become apparent that the improvement of market fuel quality is essential as well as the development in engine and exhaust after-treatment technology. Japan Clean Air Program II (JCAP II) is being conducted to assess the direction of future technologies through the evaluation of current automobile and fuel technologies and consequently to realize near zero emissions and carbon dioxide (CO2) emission reduction. In this program, effects of fuel properties on the performance of diesel engines and a vehicle equipped with two types of diesel NOx emission after-treatment devices, a Urea-SCR system and a NOx storage reduction (NSR) catalyst system, were examined.
Technical Paper

Study on Haptic Maneuver Guidance by Periodic Knocks on Accelerator Pedal

This study proposes a method for presenting maneuver request information of accelerator pedal to a driver via the accelerator pedal itself. By applying periodic force like vibration on an accelerator pedal, information is transferred to the driver without displacing the accelerator pedal. In this study, the authors focus on a saw-tooth wave as the periodic force. When the saw-tooth-waved force is applied on the accelerator pedal, a human driver feels as if the accelerator pedal is knocked by someone periodically. In addition, information about the quantity of requested maneuver can be transferred by the amplitude of the saw-tooth wave. Based on these facts, the saw-tooth wave is modified and optimized empirically with ten human drivers so that the information of direction is transferred most reliably. In addition, the relationship between the amplitude of the saw-tooth wave and requested quantity of the pedal maneuver that the drivers feel is formulated.
Journal Article

Study of the Impact of High Biodiesel Blends on Engine Oil Performance

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. This report is designed to determine how high biodiesel blends affect oil quality through testing on 2005 regulations engines with DPFs. When blends of 10-20% rapeseed methyl ester (RME) with diesel fuel are employed with 10W-30 engine oil, the oil change interval is reduced to about a half due to a drop in oil pressure. The oil pressure drop occurs because of the reduced kinematic viscosity of engine oil, which resulting from dilution of poorly evaporated RME with engine oil and its accumulation, however, leading to increased wear of piston top rings and cylinder liners.
Technical Paper

Safety Evaluation on Fuel Cell Stacks Fire and Toxicity Evaluation of Material Combustion Gas for FCV

Fuel cell vehicles represent a new system, and their safety has not yet been fully proved comparing with present automobile. Thorough safety evaluation is especially needed for the fuel system, which uses hydrogen as fuel, and the electric system, which uses a lot of electricity. The fuel cell stacks that are to be loaded on fuel cell vehicles generate electricity by reacting hydrogen and oxygen through electrolytic polymer membranes which is very thin. The safety of the fuel and electric systems should also be assessed for any abnormality that may be caused by electrolytic polymer membranes for any reasons. The purpose of our tests is to collect basic data to ultimately establish safety standards for fuel cell stacks. Methanol pool flame exposure tests were conducted on stationary use fuel cell stacks of two 200W to evaluate safety in the event of a fire.
Technical Paper

SOF Component of Lubricant Oil on Diesel PM in a High Boosted and Cooled EGR Engine

The engine in the research is a single cylinder DI diesel using the emission reduction techniques such as high boost, high injection pressure and broad range and high quantity of exhaust gas recirculation (EGR). The study especially focuses on the reduction of particulate matter (PM) under the engine operating conditions. In the experiment the authors measured engine performance, exhaust gases and mass of PM by low sulfur fuel such as 3 ppm and low sulfur lubricant oil such as 0.26%. Then the PM components were divided into soluble organic fraction (SOF) and insoluble organic fraction (ISOF) and they were measured at each engine condition. The mass of SOF was measured from the fuel fraction and lubricant oil fraction by gas chromatography. Also each mass of soot fraction and sulfate fraction was measured as components of ISOF. The experiment was conducted at BMEP = 2.0 MPa as full load condition of the engine and changing EGR rate from 0% to 40 %.
Technical Paper

Regional Trade and Emission Gas in Asian Automobile Industry

This paper is an attempt to estimate the traffic demand of private vehicles in the Philippines and Thailand toward 2030. Estimation of road traffic volume is one of the most important elements for determining fuel consumption and emission gas levels. The level of passenger car ownership is still low, but there has been a distinct shift toward passenger cars due to the lack of mass transport. In Asian countries, inspection and maintenance and emission standards are the most important policy measures. The projections of car stock are evaluated as the emissions of PM, CO and NOx by applying these policy measures in the case of Thailand.
Technical Paper

R&D and Analysis of Energy Consumption Improvement Factor for Advanced Clean Energy HEVs

Ultra-low energy consumption and ultra-low emission vehicle technologies have been developed by combining petroleum-alternative clean energy with a hybrid electric vehicle (HEV) system. Their component technologies cover a wide range of vehicle types, such as passenger cars, delivery trucks, and city buses, adsorbed natural gas (ANG), compressed natural gas (CNG), and dimethyl ether (DME) as fuels, series (S-HEV) and series/parallel (SP-HEV) for hybrid types, and as energy storage systems (ESSs), flywheel batteries (FWBs), capacitors, and lithium-ion (Li-ion) batteries. Evaluation tests confirmed that the energy consumption of the developed vehicles is 1/2 of that of conventional diesel vehicles, and the exhaust emission levels are comparable to Japan's ultra-low emission vehicle (J-ULEV) level.
Technical Paper

Oxidation Degradation and Acid Generation in Diesel Fuel Containing 5% FAME

Compared with diesel fuel, FAME is relatively unstable and readily generates acids such as acetic acid and propionic acid. When FAME-blended diesel fuel is used in existing diesel vehicles, it is important to maintain the concentration of FAME-origin acid in the fuel at an appropriately low level to assure vehicle safety. In the present study, the oxidation of diesel fuel containing 5% FAME is investigated. Several kinds of FAMEs were examined, including reagents such as methyl linoleate and methyl linolenate, as well as commercially available products. The level of acid, peroxide, water, and methanol and the pressure of the testing vessel were measured. The result shows that unsaturated FAMEs that have two or more double bonds are unstable. Also, water is generated by oxidation of FAME blended diesel fuel, accelerating corrosion of the terne sheet.
Technical Paper

Outline of the Advanced Clean Energy Vehicle Project

The Advanced Clean Energy Vehicle Project (ACE Project) has been initiated to develop the vehicles which can utilize oil-alternative and clean fuels and achieve twice the energy efficiency of conventional vehicles. To achieve the project objectives, Japanese automobile manufactures are developing six types of hybrid vehicles. Technologies of the developing vehicles include many kinds of hybrid elements, such as series and series/parallel types, alternative fuels (natural gas, DME, methanol) internal combustion engines and a fuel cell, as well as flywheels, ultra-capacitors and Li-ion batteries. This paper introduces the outline of ACE project.
Technical Paper

One Approach to Definition of MSILs and Their Connections with ASILs

ISO 26262 (Road vehicles - Functional safety), a functional safety standard for motor vehicles, was published in November 2011. In this standard, hazardous events associated with each item constituting a safety-related system are assessed according to three criteria, namely, Severity, Exposure, and Controllability, thereby determining ASILs (Automotive Safety Integrity Levels) representing safety levels for motor vehicles. Although motorcycles are not included in the scope of application of the current edition of ISO 26262, it is expected that motorcycles will be included in the next revision. However, it is not appropriate to directly apply ASILs to motorcycles. In the first place, the situation of usage in practice presumably differs between motorcycles and motor vehicles. Accordingly, in this research, we attempted to newly define Motorcycle Safety Integrity Levels (MSILs).
Technical Paper

O-PM / Emitted Matters Caused by Two-Stroke Engine Oil and Its Reduction

In recent research, decreasing oil consumption and using a synthetic oil have been shown to be effective methods of reducing smoke emissions. However, the investigation of the constituents of white smoke and its environmental effect on humans have not been undertaken. The purpose of this investigation is to clarify the characteristics and compositions of white smoke and to analyze its environmental effect on humans using Ames test, and to evaluate a control for reduction of emitted matter by steady-state engine tests. Emitted matters(EM) from synthetic oil is less than that of semi-synthetic and mineral oils under the same test conditions. Emission after treatment resulted in the lowest EM when simulating the results of the ISO 6460 test, which results showed a decrease to about 1/10. EM from two-stroke engine mainly consists of unburned engine-oil and more than 95 % of EM is soluble organic fraction (SOF).
Technical Paper

Methanol Lean Burn in an Auto-Ignition DI Engine

A new combustion system targeting a drastic decrease in NOx emission and a brake specific energy consumption equivalent to that of a DI diesel engine has been developed. In this new combustion system, a lean burn system using early injection was employed to reduce NOx emission and an auto-ignition DI engine system was employed to achieve the low energy consumption. Methanol was used as the fuel for reducing NOx emission. The objective of this study is to clarify the possibility of the system for the auto-ignition of a premixed lean mixture of methanol fuel. This study shows that the gas temperature at ignition, Tig, is the predominant factor affecting auto-ignition. Auto-ignition occurs when Tig exceeds approximately 1000K. The methanol lean burn system in an auto-ignition DI engine drastically decreased NOx emission with almost the same brake specific energy consumption as a diesel engine in the middle load region.
Technical Paper

Measuring Method of Fuel Consumption for Natural Gas Vehicles

To achieve high-accuracy measurements of fuel consumption in testing on natural gas vehicles, a method for measuring the absolute value of fuel consumption by the gravimetric method using certificated reference weights and an electric platform scale has been developed. By performing a flow-meter test and a chassis dynamometer test using the gravimetric method, the measurement accuracy of the value of fuel flow rate and fuel consumption obtained by the fuel flow meters, carbon balance method, and air-to-fuel ratio method was evaluated. As a result, a highly accurate method for measuring fuel consumption in chassis dynamometer tests has been confirmed.
Technical Paper

Lubricity of Liquefied Gas Assessment of Multi-Pressure/Temperature High-Frequency Reciprocating Rig (MPT-HFRR) -DME Fuel for Diesel

In this study, a MPT-HFRR (Multi-Pressure/Temperature High-Frequency Reciprocating Rig) was manufactured based on a diesel fuel lubricity test apparatus. The MPT-HFRR was designed to be used for conventional test methods as well as for liquefied gas fuel tests. Lubricity tests performed on a calibration standard sample under both atmospheric pressure and high pressure produced essentially constant values, so it was determined that this apparatus could be used for assessing the lubricity of fuel. Using this apparatus, the improvement of lubricity due to the addition of a DME (Dimethyl Ether) fuel additive was investigated. It was found that when 50ppm or more of a fatty acid lubricity improver was added, the wear scar diameter converged to 400μm or less, and a value close to the measured result for Diesel fuel was obtained. The lubricity obtained was considered to be generally satisfactory.
Technical Paper

Lubricity of Liquefied Gas - Assessment of the Various Pressure and Temperature High-Frequency Reciprocating Rig (VPT-HFRR) - LPG Blended Fuel for Diesel Engine

In this research, a test apparatus (VPT-HFRR) for evaluating lubricity was manufactured at an arbitrary pressure according to the lubricity test method (HFRR) for diesel fuel. The lubricity of LPG blended fuel (LBF) for diesel engines was examined using VPT-HFRR., This was a value close to that of diesel fuel, and when a suitable lubricity had been maintained, it was checked. Prototype trucks were manufactured and their durability was examined. After a run of 70,000km or more, no serious trouble had occurred, and when LBF was maintained at a suitable lubricity, it was checked.