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Since ethanol is a renewable source of energy and it contributes to lower CO2 emissions, ethanol produced from biomass is expected to increase in use as an alternative fuel. It is recognized that for spark ignition (SI) engines ethanol has advantages of high octane number and high combustion speed and has a disadvantage of difficult startability at low temperature. This paper investigates the influence of ethanol fuel on SI engine performance, thermal efficiency, and emissions. The combustion characteristics under cold engine conditions are also examined. Ethanol has high anti-knock quality due to its high octane number, and high latent heat of evaporation, which decreases the compressed gas temperature during the compression stroke. In addition to the effect of latent heat of evaporation, the difference of combustion products compared with gasoline further decreases combustion temperature, thereby reducing cooling heat loss.

Toyota has been introducing several hybrid vehicles (HV) since 1997 as a countermeasure to the concerns raised by automobile, like CO2 reduction, energy security, and pollutant emission reduction in urban areas. Plug in hybrid Vehicle (PHV) uses electric energy from grid rather than fuel for most short trips and therefore presents a next step forward towards an even more effective solution for these concerns. For longer trips, the PHV works as a conventional hybrid vehicle, providing all the benefits of Toyota full hybrid technology, such as low fuel consumption, user-friendliness and long cruising range. This paper describes a newly developed plug-in hybrid system and its vehicle performance. This system uses a Li-ion battery with high energy density and has an EV-range within usual trip length without sacrificing cabin space.

JCAPII gasoline workgroup reported vehicle emission study to comprehend the impact of ETBE blending. In previous study, we focused on the compatibility of ETBE blended gasoline with Japanese current gasoline vehicles in-use. Based on recent discussion with ETBE 8% blended gasoline into the market, more information becomes necessary. In this second report, we studied to comprehend the actual emission impact using realistic model fuels using several base stocks. Fuel properties of T50, T90 and aromatic compound content were selected through discussions. Specifications were changed within the range of the market. Both ETBE 0% and 8% were combined for these fuel matrixes. In total, eight fuels and two reference fuels were tested. Two J-ULEV vehicles (one MPI, and a stoichiometric-SIDI) were procured as representatives. We discussed quantitative and qualitative impact toward emissions. Data regarding CO2 and fuel economy change were also reported.

Internal combustion engines will play an important role in the coming decades, even considering targets of carbon neutrality for a sustainable future. This will be especially true in regions where pure electrified vehicle implementation is not yet practical, or for long-range heavy load transportation purposes, even in regions where BEV infrastructure is well established. HEV/PHEV’s importance and contribution to CO2 emission reduction together with carbon neutral fuels such as hydrogen, e-fuel and biomass fuel etc. will remain crucial regardless of region/transport sectors. In this respect, brake thermal efficiency improvements by friction reduction needs further investigation. This is especially so with the crankshaft bearings’ lubrication system, which can provide as much as 40% of the total mechanical losses in some cases. It is a well-established fact, that plain bearings require a minimum oil flow volume to maintain their real function rather than oil pressure.

Solar and other green energy technologies are attracting attention as a means of helping to address global warming caused by CO2 and other emission gases. Countries, factories, and individual homes around the world have already introduced photovoltaic energy power sources, a trend that is likely to increase in the future. Electric vehicles powered from photovoltaic energy systems can help decrease the CO2 emmissions caused by vehicles. Unlike vehicles used for solar car racing, it is not easy to equip conventional vehicles with solar modules because the available area for module installation is very small to maintain cabin space, and the body lines of conventional vehicles are also usually slightly rounded. These factors decrease the performance of photovoltaic energy systems and prevent sufficient electric power generation. This research aimed to estimate the effectiveness of a solar module power generating system equipped on a conventional car, the Toyota Prius PHV.

To meet increasing driveability expectation and government stringent fuel economy regulations reducing CO2 emissions of passenger cars; Toyota developed a new 8-speed automatic transmission "Direct Shift-8AT". Direct Shift-8AT is the first stepped automatic transmission model based on “TNGA” philosophy. New models which received Direct Shift-8AT are the new Camry, Highlander and Sienna. Direct Shift-8AT has an innovative control method with gear train and torque converter models, providing enhanced driveability and fuel economy performance through high efficiency transmission technology. This paper describes details of the new technology and vehicle performance.

It is necessary for us to reduce CO2 emissions in order to hold down global warming which is advancing year by year. Toyota Motor Corporation believes that not only the introduction of BEVs but also the sale of the hybrid vehicles must spread in order to achieve the necessary CO2 reduction. Therefore, we planned to improve the attractiveness of future hybrid vehicles. Prius has always made full use of hybrid technologies and leading to significant CO2 reduction. Toyota Motor Corporation has developed a 2.0L hybrid system for the new Prius. We built the system which could achieve a comfortable drive along following the customer’s intention while improving the fuel economy more than a conventional system. The engine improves on both output and thermal efficiency. The transaxle decreases mechanical loss by downsizing the differential, and adoption of low viscosity oil.

To solve various environmental problems, fuel-efficient vehicles that reduce CO2 emissions as well as exhaust gas emissions have been developed. In such vehicles, a regenerative brake is used to further reduce fuel consumption. Because the market size for such vehicles is expanding, a brake system is required that can be used in a wide range of vehicles extending from internal combustion engine vehicles (ICEVs) to electric vehicles (EVs). In addition, issues such as deceleration fluctuation and brake pedal fluctuation arise because the regenerative brake force is dependent on the vehicle speed. This paper presents a brake system configuration and its element technologies that can replace existing brake systems in different vehicles ranging from ICEVs to EVs. The proposed system can realize a regenerative cooperative brake not only by replacing the brake booster unit but also without replacing the modulator.

Further fuel economy improvement of the internal combustion engine is indispensable for CO2 reduction in order to cope with serious global environmental problems. Although lowering the viscosity of engine oil is an effective way to improve fuel economy, it may reduce the wear resistance. Therefore, it is important to achieve both improved fuel economy and reliability. We have developed new 0W- 8 engine oil of ultra-low viscosity and achieved an improvement in fuel economy by 0.8% compared to the commercial 0W-16 engine oil. For this new oil, we reduced the friction coefficient under boundary lubrication regime by applying an oil film former and calcium borate detergent. The film former increased the oil film thickness without increasing the oil viscosity. The calcium borate detergent enhanced the friction reduction effect of molybdenum dithiocarbamate (MoDTC).

To achieve carbon neutrality by reducing carbon dioxide (CO2) emissions, vehicles with an internal combustion engine have started to be replaced by electrification vehicles such as hybrid electric vehicles (HEVs), plug-in HEVs (PHEVs), and battery EVs (BEVs) worldwide, which have motors in their transaxles (T/As). Reducing transmission torque loss in the transaxles is effective to reduce CO2 emissions, and lowering the viscosity of lubrication fluids in T/As is a promising method for reducing churning and drag loss. However, lowering viscosity generally leads to thin oil films and makes the lubrication condition severe, resulting in worse anti-fatigue and anti-seizure performance. To deal with these issues, we made improvements on the additive formulation of fluid, such as the addition of an oil-film-forming polymer, chemical structure change of calcium detergents, and an increase of anti-wear additives including phosphorus and sulfur.

Toyota has been introducing several hybrid vehicles (HV) as a countermeasure to concerns related to the automotive mobility like CO2 reduction, energy security, and emission reduction in urban areas. A next step towards an even more effective solution for these concerns is a plug-in hybrid vehicle (PHV). This vehicle combines the advantages of electric vehicles (EV), which can use clean electric energy, and HV with it's high environmental potential and user-friendliness comparable to conventional vehicles such as a long cruising range. This paper describes a newly developed plug-in hybrid system and its vehicle performance. This system uses a Li-ion battery with high energy density and has an EV-range within usual trip length without sacrificing cabin space. The vehicle achieves a CO2 emission of 59g/km and meets the most stringent emission regulations in the world. The new PHV is a forerunner of the large-scale mass production PHV which will be introduced in two years.

The reduction of CO2 emissions has become an imperative duty in order to cope with environmental compliance. For car manufacturers, CO2 emission has been set by regulation and many consumers prefer a fuel efficient car because of the increasing fuel price. In such a situation, reducing engine friction is an effective way of improving fuel efficiency. Among engine parts, the piston counts for a large percentage of the friction losses. In this study, we established a calculation model for estimating piston and piston ring friction. This paper shows how the accuracy of the calculation model was improved by validating against measurements.

In this study, instead of investigating NOx storage reaction improvements, the NOx adsorption phenomenon was focused on and analyzed to improve NOx trapping performance at lower temperatures. As a NOx adsorbing material, "Ag" was expected to enhance NOx adsorption and reduce the sulfur regeneration temperature due to the abundance of adsorbed oxygen and moderate basicity. However, when using this material in an actual system, we had to reduce the sulfur regeneration temperature, increase NOx adsorption capacity and improve NOx desorption further. Addition of TiO₂, working as an acidic material, was found to decrease sulfur regeneration temperature. Additionally, it increased the NOx adsorption capacity through improved Ag dispersion which plays an important role in NOx adsorbing. Consequently, a greater NOx trapping performance than NSR catalyst was achieved at lower temperatures.

Reducing vehicle CO2 emissions is an important measure to help address global warming. To reduce CO2 emissions on a global basis, Toyota Motor Corporation is taking a multi-pathway approach that involves the introduction of the optimal powertrains according to the circumstances of each region, including hybrid electric (HEVs) and plug-in hybrid electric vehicles (PHEVs), as well as battery electric vehicles (BEVs). This report describes the development of a new PHEV system for the Toyota Prius. This system features a traction battery pack structure, transaxle, and power control unit (PCU) with boost converter, which were newly developed based on the 2.0-liter HEV system. As a result, the battery capacity was increased by 1.5 times compared to the previous model with almost the same battery pack size. Transmission efficiency was also improved, extending the distance that the Prius can be driven as an EV by 70%.

We report in this paper our newly developed technology applied to ILSAC GF-5 0W-20 engine oil that offers great fuel economy improvement over GF-4 counterpart, which is a key performance requirement of modern engine oil to reduce CO2 emissions from a vehicle. Our development strategy of the oil consisted of two elements: (1) further friction reduction under mixed and hydrodynamic lubrication conditions considering use of roller rocker arm type valve train system and (2) lowering viscosity at low temperature conditions to improve fuel economy under cold cycles. Use of roller rocker arm type valve train system has been spreading, because of its advantage of reducing mechanical friction. Unlike engine with conventional direct-acting type valve train system, lubrication condition of engine with the roller rocker arm type valve train system has higher contribution of mixed or hydrodynamic lubrication conditions rather than boundary lubrication condition.

Mass reduction of parts is growing in importance as a means for reducing CO2 emissions from vehicles.The aim of the present research was to contribute to further mass reduction of pistons by developing a new aluminum casting material with highest level of fatigue strength. This goal was achieved using a development concept of creating a homogeneous structure in which Ti was added to create a fine structure and appropriate quantities of Fe and Mn were added to form a compound that is stable at high temperatures. Stand-alone tests of prototype pistons fabricated using the developed material show that the material is 14% stronger than the conventional material, thereby enabling increases in power and mass reduction.

In the automobile industry, interest in the prevention of global warming has always been high. The development of eco cars (HV, EV etc.), aimed at reducing CO2 emissions during operation, has been progressing. In the announcement of its "Toyota Environmental Challenge 2050", Toyota declared its commitment to creating a future in which people, cars, and nature coexist in harmony. In this declaration, Toyota committed to reducing CO2 emissions not only during operation but also over the entire life cycle of vehicles, and to using resources effectively based on a 4 R’s approach (refuse, reduce, reuse, and recycle). Although eco cars decrease CO2 emissions during operation, most of them increase CO2 emissions during manufacturing. For example, the rare-earths (Nd, Dy etc.) used in the magnets of driving motors are extracted through processes that produce a significant amount of CO2 emissions.

Fuel consumption and CO2 emission regulations for vehicles, such as the Zero Emission Vehicle (ZEV) Regulation, motivate renewable energy technologies in the automotive industry. Therefore, the automotive industry is focused on adopting solar charging systems. Some vehicles have adopted solar energy to power the ventilation system, but these vehicles do not use solar energy to power the drivetrain. One important issue facing the design of solar charging systems is the low power generated by solar panels. Compared to solar panels for residential use, solar panels for vehicles can’t generate as much power because of size and weight limitations. Also, the power generated by solar panels can be extremely affected depending on differences in solar radiation among the cells. Therefore, Toyota has developed a solar charging system that can use solar energy for driving the Prius PHV. This system can efficiently charge the hybrid battery with the low power generated by the solar panel.

The effects of intake dilution with various dilution gases including nitrogen, argon, and carbon dioxide on low temperature diesel combustion were investigated in a naturally aspirated DI diesel engine to understand the mechanism of the simultaneous reductions in smoke and NOx with ultra-high EGR. NOx almost completely disappears with the intake oxygen concentration diluted below 16% regardless of the kind of dilution gas. Smoke emissions decrease with increased heat capacity of the charged gas due to promotion of mixture homogeneity with longer ignition delays. Intake dilution with the 36% CO2 + 64% Ar mixture which has a similar specific heat capacity as N2 shows lower smoke emissions than with N2. Chemical kinetics analysis shows that carbon dioxide may help to reduce NOx and soot by lowering the reaction temperature as well as by changing the concentrations of some radicals or/and species related to soot and NOx formation.

Since the regulations of CO2 emissions have been tightened in each country recently, each automotive manufacturer has responded by bringing competitive technologies that maximize efficiency while promoting vehicle electrification such as xEV. Not only the efficiency, we need to meet or exceed occupant performance and comfort expectations. The climate control system expends a large amount of energy to keep a comfortable environment, having a significant impact on fuel consumption and EV driving range. Therefore, many manufacturers try to save energy and improve occupant comfort quickly by using not only the conventional convective heating by HVAC but also the conductive heating to heat the human body directly such as seat and steering wheel heater. In this study, a radiative heater, which is more efficient than a convective heating to warm anterior thigh and shin where a conductive heating cannot warm, was applied to vehicle.