Yoshinori Kondo

CO2 Emissions in Japan: Influences of imports and exports

The amounts of CO2 embodied in imports to, and exports from, Japan have been estimated using input-output tables, assuming imported commodities have the same CO2 emission intensities as those of the corresponding Japanese products. The concept of the attributed CO2 emission to each country was introduced. Until 1985 in Japan, the amount of CO2 embodied in exports had been larger than that in its imports, but, by 1990, such a situation had been reversed.

Size distribution and characterization of ultrafine particles in roadside atmosphere

Abstract The number concentration and number size distributions of ultrafine particles were measured with a Scanning Mobility Particle Sizer (SMPS) at a roadside in early autumn and winter, and the results are discussed with regard to the contribution of traffic activity and meteorological conditions. The number concentration of the <50 nm fraction increased in the morning under calm wind conditions, and this increase corresponded with the increase in total traffic volume and nitric oxide. The increase in ultrafine particles was influenced not only by the increase in total traffic but also by the high contribution of diesel engine vehicles. The number concentration decreased around noon as the wind speed increased, although the total traffic and the number of diesel engine vehicles were at the same level as in the morning. The number size distribution in the morning was bimodal, with a first peak diameter of around 30 nm and a second of around 90 nm in both periods. The volatility of ultrafine particles was investigated using a thermal denuder operating at 250°C. The first peak consisted mainly of volatile components, whereas the second one consisted of solid materials plus some volatile components. These results were consistent with the mass size distribution of elemental and organic carbon. The number size distribution with a peak diameter of around 30 nm was also observed in the afternoon at a suburban site; however, it was produced not by vehicle emissions directly but by photochemical reactions. Although a relatively high number concentration was also observed in the morning at the suburban site due to vehicle emission, the peak diameter ranged from 40 to 90 nm, which was larger than at the roadside.

Comparison of Size Distribution of Ultra fine Particles in Roadside Atmosphere and Diesel Exhaust

The size distributions of ultra fine particles in diesel exhaust were measured in a dilution tunnel at a high dilution ratio, and the results were compared with roadside measurements. The size distribution in diesel exhaust showed a single mode with a peak around 50 nm; in roadside atmosphere there was a bimodal distribution with peaks around 20 and 100 nm. Coagulation of diesel particles in the atmosphere was examined with an exhaust gas dispersion chamber. Coagulation of particles in the atmosphere and transient driving conditions of vehicle may cause the difference in size distribution between bench test results and roadside measurements.

Difference in concentration trends of airborne particulate matter during rush hour on weekdays and Sundays in Tokyo, Japan

Suspended particulate matter (SPM) and fine particulate matter (less than or equal to 2.5 μm: PM2.5) have generally been decreasing for the last decade in Tokyo, Japan. To elucidate the major cause of this decrease, the authors investigated the different trends of airborne particulates (both SPM and PM2.5 concentrations) by evaluating comparisons based on the location of the monitoring stations (roadside vs. ambient), days of the week (weekdays vs. Sundays), and daily fluctuation patterns (2002 vs. 2010). Hourly mean SPM and PM2.5 concentrations were obtained at four monitoring stations (two roadside stations, two ambient stations) in Tokyo, Japan. Annual mean concentrations of each day of the week and of each hour of the day from 2002 to 2010 were calculated. The results showed that (1) the daily differences in annual mean concentration decreased only at the two roadside monitoring stations; (2) the high hourly mean concentrations observed on weekdays during the daily rush hour at the two roadside monitoring stations observed in 2002 diminished in 2010; (3) the SPM concentration that decreased the most since 2002 was the PM2.5 concentration; and (4) the fluctuation of hourly concentrations during weekdays at the two roadside monitoring stations decreased. A decreasing trend of airborne particulates during the daily rush hour in Tokyo, Japan, was observed at the roadside monitoring stations on weekdays since 2002. The decreasing PM2.5 concentration resulted in this decreasing trend of airborne particulate concentrations during the daily rush hours on weekdays, which indicates fewer emissions were produced by diesel vehicles. Implications The authors compared the trends of SPM and PM2.5 in Tokyo by location (roadside vs. ambient), days of the week (weekdays vs. Sundays), and daily fluctuation patterns (2002 vs. 2010). The high hourly mean concentrations observed at the roadside location during rush hour on weekdays in 2002 diminished in 2010. The SPM concentration that decreased during rush hour the most was the PM2.5 concentration. This significant decrease in the PM2.5 concentration resulted in the general decreasing trend of SPM concentrations during the rush hours on weekdays, which indicates fewer emissions were produced from diesel vehicles.

Comparative measurements of the eco-driving effect between electric and internal combustion engine vehicles

Not only ICEV user but also EV users have interest in eco-driving. So, in this study, quantitative evaluation of eco-driving effect for EV was conducted using chassis dynamometer with new developed “Eco-driving test mode”. They were extracted from seventy two real-world driving data collected at the Eco-driving test-ride event. And they had four speed patterns which had same travel distance of 5.2 km and wide range of kinematic running energy. Three ICEVs, one HEV and two EVs were tested. The results showed that good linear relationships were found between kinematic running energy and fuel consumption rate for all 6 tested vehicles. Thus, eco-driving with low kinematic running energy by observing speed limit and constant speed was effective to not only ICE but also HEV and EV. The eco-driving effects from averaged drive as usual to averaged eco-driving in the eco-driving test-ride were estimated. And the effects of 660cc CTV ICEV, 1,300cc CVT ICEV, 1,800cc 4AT ICEV, 1,500cc HEV, EV type A and EV type B were 12.0%, 12.2%, 10.9%, 12.6%, 18.4% and 11.7% respectively. And the results indicated that EV had higher potential of eco-driving effect than ICEV if EV could maintain high energy conversion efficiency with various driving situations.

To what extent can speed management alleviate the range anxiety of EV

Based on actual use data recorded by a volunteer driving an EV under the condition that the distance involved in his weekday commute to and from the workplace was almost equal to the catalogue travel mileage, both speed management and refraining from the use of auxiliary devices such as the heater are indicated as measures to alleviate the range anxiety of the EV. Firstly, to clarify the performance specifics, electricity consumption rate (ECR) when using the highway or public roads and when using auxiliary devices was calculated. Highway driving involved 1.4-1.9 times higher average speed and 1.2-1.3 times higher ECR when compared to driving on public roads. ECR when using the heater increased to 1.4 times the value when no auxiliary devices were used. The use of headlights, wiper, or air conditioning had a relatively small effect on ECR. On the basis of these results, the effect on actual vehicle range extension of reduction of cruising speeds on the highway was evaluated and speed reductions of 10 km/h from 100 to 90 and 20 from 100 to 80 gave 7% and 12% improvement in actual vehicle range, respectively. The effect of speed management on the ECR was smaller than the non-use of the heater but larger than the non-use of air conditioning.

Evaluation of torsional rigidity of frame for electric Eco-Vehicle: deformation behavior of light thin shell structure subjected to torsion and bending

Abstract The frame of the electric Eco-Vehicle is required to be as light as possible and to have enough room for many batteries. The frame assembled with thin aluminium plate instead of solid is thought to be advantageous. In this study, torsion tests and the finite element method calculation of a structure unit for Eco-Vehicle were conducted. The torsional deformation of thin shell structure was found to be explained by the theory of the bending of a thin plate rather than that of the pure torsion of a beam. Some examples of the optimized models of reinforced frame were also shown.

Characterization of structure of single particles from various automobile engines under steady-state conditions

ABSTRACT The effective density ρeff of particles emitted from various types of automobile engines was measured using a differential mobility analyzer (DMA)–aerosol particle mass analyzer method, and their morphology was investigated via transmission electron microscopy analysis. The measured exhaust particles were particles emitted from diesel engines (DEs), gasoline direct injection spark ignition (DISI) engines, gasoline port fuel injection (PFI) engines, and liquefied petroleum gas (LPG) engines. ρeff and the morphology of the particles were measured after classification with the DMA, and six electrical mobility diameters Dm ranging from 30 to 300 nm were selected. ρeff was found to decrease as Dm increased for all particles. A morphological study showed that DE and DISI particles were mainly agglomerates and PFI and LPG particles were mainly nonagglomerates. Numbers and diameters of the primary particles in the agglomerates showed no systematic differences between DE and DISI particles at a given Dm. Rather, the primary particle diameter dp increased with increasing Dm of the agglomerates; the empirical relationship between the two diameters was found to be dp = 8.498ln(Dm) – 12.781 for DE and DISI particles. The core (elemental carbon) diameters in the primary particles of the DE particles increased as Dm increased and were estimated to range from 8.5 nm for Dm = 70 nm to 22.1 nm for Dm = 300 nm. Although the primary particle diameter and core diameter depend on Dm, the organic coating (shell) thickness, which ranged from 5.1 to 7.4 nm, was found to be independent of Dm. Copyright