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Technical Paper

Water Jacket Spacer for Improvement of Cylinder Bore Temperature Distribution

2005-04-11
2005-01-1156
For reduction of fuel consumption, a new device “Water Jacket Spacer” which improves temperature distribution of a cylinder block bore wall was developed. In the case of a conventional cylinder block, coolant flow concentrates at the bottom and middle region of the water jacket. While temperature of the upper bore wall is high (due to high-temperature combustion gas) the temperature of the lower bore wall is low, since its only function is to support the piston. When the developed spacer is inserted into a water jacket, the coolant flow concentrates at the upper part of the jacket. As a result, cooling ability to the upper bore wall was improved and temperature of lower bore wall was increased, thereby reducing fuel consumption.
Journal Article

Unsteady Aerodynamic Response of a Vehicle by Natural Wind Generator of a Full-Scale Wind Tunnel

2017-03-28
2017-01-1549
In recent years, the automotive manufacturers have been working to reduce fuel consumption in order to cut down on CO2 emissions, promoting weight reduction as one of the fuel saving countermeasures. On the other hand, this trend of weight reduction is well known to reduce vehicle stability in response to disturbances. Thus, automotive aerodynamic development is required not only to reduce aerodynamic drag, which contributes directly to lower fuel consumption, but also to develop technology for controlling unstable vehicle behavior caused by natural wind. In order to control the unstable vehicle motion changed by external contour modification, it is necessary to understand unsteady aerodynamic forces that fluctuating natural wind in real-world environments exerts on vehicles. In the past, some studies have reported the characteristics of unsteady aerodynamic forces induced by natural winds, comparing to steady aerodynamic forces obtained from conventional wind tunnel tests.
Technical Paper

Toyota Newly Developed 2VZ-FE Type Engine

1988-11-01
881775
Newly developed 2VZ-FE engine for CAMRY is a 2.5-liter water cooled and V-type 6-cylinder engine exported from TOYOTA for the first time. This engine has the TOYOTA original 4-valve DOHC system. That is, exhaust camshafts driven by intake camshafts using scissors gears. By its compact configuration with the gear driven camshafts, this V-type 6-cylinder engine is mounted on a front-wheel-drive vehicle which originally had an in-line 4-cylinder engine. By increasing IVZ-FE engine displacement (for domestic), compact pentroof-type combustion chambers, optimum air-fuel ratio and ignition timing by TCCS (TOYOTA Computer Controlled System) and other technologies, a high performance 153HP/5600rpm and a large torque 155ft·lbs/4400rpm have been achieved with a low fuel consumption.
Technical Paper

Thermal Management of a Hybrid Vehicle Using a Heat Pump

2019-04-02
2019-01-0502
This paper presents the thermal management of a hybrid vehicle (HV) by using a heat pump system in cold weather. The advantage of an HV is a high efficiency of the vehicle system since an electric motor and an engine are coupled and optimally controlled. However, in the conventional HV, we see the fuel economy degradation in cold weather because delivering heat to the passenger cabin by using an engine results in a low efficiency of the vehicle system. To improve the fuel economy degradation, in this study, a heat pump is used and combined with an engine for the thermal management. The heat pump with an electrically driven compressor pumps heat from ambient into a water-cooled condenser. The heat which is generated by the engine and the heat pump is delivered to the engine and the passenger cabin because the engine needs to warm up quickly to reduce the emission and the cabin needs heat for thermal comfort.
Technical Paper

The Power Performance and the Fuel Economy Estimation of HV for Vehicle Concept Planning Using VHDL-AMS Full Vehicle Simulation

2012-04-16
2012-01-1025
In order to reduce CO₂, Electric Vehicles (EV) and Hybrid Vehicles (HV) are effective. Those types of vehicles have powertrains from conventional vehicles. Those new powertrains drastically improve their efficiency from conventional vehicles keeping the same or superior power performance. On the other hand, those vehicles have an issue for thermal energy shortage during warming up process. The thermal energy is very large, and seriously affects the fuel economy for HV and the mileage for EV. In this paper, we propose VHDL-AMS multi-domain simulation technique for the estimation of the vehicle performance at the concept planning stage. The VHDL-AMS is IEEE and IEC standardized language, which supports not only multi-domain (physics) but also encryption. The common modeling language and encryption standard is indispensable for full-vehicle simulation.
Journal Article

The Impact of Diesel and Biodiesel Fuel Composition on a Euro V HSDI Engine with Advanced DPNR Emissions Control

2009-06-15
2009-01-1903
In an effort to reduce CO2 emissions, governments are increasingly mandating the use of various levels of biofuels. While this is strongly supported in principle within the energy and transportation industries, the impact of these mandates on the transport stock’s CO2 emissions and overall operating efficiency has yet to be fully explored. This paper provides information on studies to assess biodiesel influences and effects on engine performance, driveability, emissions and fuel consumption on state-of-the-art Euro IV compliant Toyota Avensis D4-D vehicles with DPNR aftertreatment systems. Two fuel matrices (Phases 1 & 2) were designed to look at the impact of fuel composition on vehicle operation using a wide range of critical parameters such as cetane number, density, distillation and biofuel (FAME) level and type, which can be found within the current global range of Diesel fuel qualities.
Technical Paper

Study of Future Engine Oil (First Report): Future Engine Oil Scenario

2007-07-23
2007-01-1977
In recent years, problems such as global warming, the depletion of natural resources, and air pollution caused by emissions are emerging on a global scale. These problems call for efforts directed toward the development of fuel-efficient engines and exhaust gas reduction measures. As a solution to these issues, performance improvements should be achieved on the oil that lubricates the sliding sections of engines. This report points to features required of future engine oil-such as contribution to fuel consumption, minimized adverse effects on the exhaust gas aftertreatment system, and improved reliability achieved by sludge reduction-and discusses the significance of these features. For engine oil to contribution of engine oil to lower fuel consumption, we examined the effects of reduced oil viscosity on friction using gasoline and diesel engines.
Technical Paper

Small Bore Diesel Engine Combustion Concept

2015-04-14
2015-01-0788
Small bore diesel engines often adopt a two-valve cylinder head and a non-central injector layout to expand the port flow passage area. This non-central injector layout causes asymmetrical gas flow and fuel distribution, resulting in worse heat losses and a less homogenous fuel-air mixture than an equivalent four-valve cylinder head layout with a central injector. This paper describes the improvement of piston bowl geometry to achieve a more homogeneous gas flow and fuel-air mixture. This concept reduced fuel consumption by 2.5% compared to the original piston bowl geometry, while also reducing NOx emissions by 10%.
Technical Paper

Noise and Vibration Reduction Technology in Hybrid Vehicle Development

2001-04-30
2001-01-1415
The world's first mass production gasoline hybrid passenger car, the “Prius”, was introduced into the Japanese market in 1997. By the time it was introduced into the American and European markets in Mid-2000, its fuel consumption and exhaust emissions had been further improved while achieving superior NV performance compared with conventional vehicles with 1.5-liter engines even in these competitive markets. This paper describes NV reduction technology for problems peculiar to the hybrid vehicle such as engine start/stop vibration, drone noise and vibration at low engine speed and motor/generator noise and vibration. It also compares the overall NV performance of the hybrid vehicle with conventional gasoline engine vehicles.
Technical Paper

Newly Developed Toyota Plug-in Hybrid System and its Vehicle Performance under Real Life Operation

2011-06-09
2011-37-0033
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.
Technical Paper

Multipoint Spark Ignition for Lean Combustion

1985-10-01
852092
Effects of multipoint spark ignition on combustion duration, fuel consumption and lean misfire limit are discussed in this paper. A plate, which consists of 12 spark gaps in each cylinder, and a new CD ignition system have been developed for accomplishing the multipoint spark ignition. This plate was installed between cylinder block and head in a 4 cylinder engine. Compared with a single gap, the results of 12 gaps showed a reduced combustion duration by about 50%, a 5% decrease in fuel consumption and an extended lean misfire limit by about 3 air-fuel ratio numbers. Furthermore, the multipoint spark ignition on both sides of the combustion chamber was more effective than only on one side. With this system, HC emission can be reduced as well. The results of this study showed that, compared to those obtained with swirl, this multipoint spark ignition was more effective on improving fuel consumption.
Journal Article

Multi Attribute Optimization: Fuel Consumption, Emissions and Driveability

2012-04-16
2012-01-0946
In making our products more attractive, it is becoming increasingly important to balance multiple areas of performance, such as fuel economy, emissions and drivability. Customer expectations and government legislations, to protect global environment, strongly increase the work complexity of auto firms in order to release high quality and eco-friendly vehicles. The balancing between several target is becoming a key factor in the car design: respect current (and anticipate future) emission limits optimization of fuel consumption insure high level of drivability maintain acceptable(or increase) performances sustain acceptable cost, reliability, etc. From recent emissions limitations, engine cold start (at the beginning of driving cycle) plays a major role in the total amount of pollutants. Especially, achievements of HC limitations are a big challenge for vehicles with a conventional spark ignition engine.
Journal Article

Low Emissions and High-Efficiency Diesel Combustion Using Highly Dispersed Spray with Restricted In-Cylinder Swirl and Squish Flows

2011-04-12
2011-01-1393
A new clean diesel combustion concept has been proposed and its excellent performance with respect to gas emissions and fuel economy were demonstrated using a single cylinder diesel engine. It features the following three items: (1) low-penetrating and highly dispersed spray using a specially designed injector with very small and numerous orifices, (2) a lower compression ratio, and (3) drastically restricted in-cylinder flow by means of very low swirl ports and a lip-less shallow dish type piston cavity. Item (1) creates a more homogeneous air-fuel mixture with early fuel injection timings, while preventing wall wetting, i.e., impingement of the spray onto the wall. In other words, this spray is suitable for premixed charge compression ignition (PCCI) operation, and can decrease both nitrogen oxides (NOx) and soot considerably when the utilization range of PCCI is maximized.
Technical Paper

Improvement of DI Diesel Engine System by Utilizing GTL Fuels Characteristics

2009-06-15
2009-01-1933
Gas To Liquid (GTL) fuels synthesized from natural gas are known as clean fuels. Therefore, GTL fuels have been expected to be a promising option that can reduce the NOx and PM emissions from diesel engines and contribute to the energy security. In this study, in order to clarify the emission reduction potentials, the improvement of DI diesel engine and aftertreatment systems were investigated by utilizing GTL fuels characteristics. To achieve a further reduction of both NOx and PM emissions, the combustion chamber, injection pattern and EGR calibration were modified. From the results of tests, the engine out NOx emissions were reduced to the Euro 6 regulation level and in parallel the expected deteriorations of HC emission and fuel consumption were suppressed because of the characteristics of high cetane number and zero poly-aromatics hydrocarbons. Additionally, an aftertreatment system was optimized to GTL fuel in order to improve NOx conversion efficiency.
Journal Article

Identification of Vortical Structure that Drastically Worsens Aerodynamic Drag on a 2-Box Vehicle using Large-scale Simulations

2016-04-05
2016-01-1585
It is important to reduce aerodynamic drag for reducing fuel consumption. Conventionally reduction of aerodynamic drag has been carried out by shape optimization of each part of a vehicle based on the investigations of the time-averaged flows around the vehicle. However, the general tendency of drag reduction has been saturated recently and it is required to develop a new flow-control technique to achieve further reduction in aerodynamic drag. We therefore focus on the unsteadiness of the flow around a vehicle to achieve it because the aerodynamic drag of a vehicle fluctuates over time due to repetitions of generation, growth, merging and disappearance of various sizes of vortices around it. These vortices are formed by flow separations, for which the longitudinal coherent vortices inside turbulent boundary layers on vehicle surfaces are presumably playing an important role.
Technical Paper

GTL Fuel Impact on DI Diesel Emissions

2007-07-23
2007-01-2004
Reduction of exhaust emissions was investigated in a modern diesel engine equipped with advanced diesel after treatment system using a Gas-to-Liquid (GTL) fuel, a cleaner burning alternative diesel fuel. This fuel has near zero sulfur and aromatics and high cetane number. Some specially prepared GTL fuel samples were used to study the effects of GTL fuel distillation characteristics on exhaust emissions before engine modification. Test results indicated that distillation range of GTL fuels has a significant impact on engine out PM. High cetane number also improved HC and CO emissions, while these fuel properties have little effect on NOx emissions. From these results, it was found that low distillation range and high cetane number GTL fuel can provide a favorable potential in NOx/PM emissions trade-off. In order to improve the tail-pipe emissions in the latest diesel engine system, the engine modifications were carried out for the most favorable GTL fuel sample.
Technical Paper

Feasibility Study of Exhaust Emissions in a Natural Gas Diesel Dual Fuel (DDF) Engine

2012-09-10
2012-01-1649
The Diesel Dual Fuel (DDF) vehicle is one of the technologies to convert diesel vehicles for natural gas usage. The purpose of this research was to study the possibility of a DDF vehicle to meet emission standards for diesel vehicles. This research was done for small passenger vehicles and commercial vehicles. The exhaust emissions compliance of such vehicles in a New European Driving Cycle (NEDC) mode which was composed of Urban Driving Cycles (UDC) and an Extra Urban Driving Cycle (EUDC) was evaluated. (see APPENDIXFigure A1) In this study, the passenger vehicle engine, compliant with the EURO4 standard, was converted to a DDF engine. Engine bench tests under steady state conditions showed similar result to previous papers. Total hydrocarbon (HC) emission was extremely high, compared to diesel engine. The NEDC mode emissions of the DDF vehicle were estimated based on these engine bench test results.
Technical Paper

Effects of Fuel Properties on Premixed Charge Compression Ignition Combustion in a Direct Injection Diesel Engine

2003-05-19
2003-01-1815
Effects of fuel distillation characteristics and cetane number on premixed charge compression ignition (PCCI) combustion were investigated for the purpose of reducing NOx and PM emissions from a direct injection diesel engine. The test engine had a hole type injection nozzle for conventional diesel combustion at high load operation. A low compression ratio and cooled EGR were applied to the test engine in order to reduce the compression temperature for avoiding pre-ignition. The investigation results show that, in the case of ignition control by EGR, a light fuel with lower distillation characteristics had an advantage of reducing smoke at higher loads. This means that high volatility fuel is effective in promoting lean mixture formation of fuel and air during the ignition delay. Moreover, lowering the cetane number was effective in reducing NOx emissions by suppression of combustion temperature.
Journal Article

Diesel Engine Emissions and Performance Optimization for Neat GTL Fuel

2008-04-14
2008-01-1405
The emissions reduction potential of neat GTL (Gas to Liquids: Fischer-Tropsch synthetic gas-oil derived from natural gas) fuels has been preliminarily evaluated by three different latest-generation diesel engines with different displacements. In addition, differences in combustion phenomena between the GTL fuels and baseline diesel fuel have been observed by means of a single cylinder engine with optical access. From these findings, one of the engines has been modified to improve both exhaust emissions and fuel consumption simultaneously, assuming the use of neat GTL fuels. The conversion efficiency of the NOx (oxides of nitrogen) reduction catalyst has also been improved.
Technical Paper

Development of “Virtual and Real Simulator” for Engine

2001-03-05
2001-01-1355
We developed a progressive system, “virtual and real simulator (V&R-S)” for engine. To innovate the process of engine development, the test system creates dynamic load of drivetrain, wheel, body and road with the virtual vehicle model. We set the phenomena such as drivetrain vibration for reproducing object of this system. The load is transmitted to the engine crankshaft end as torque with the connecting shaft made of fiberglass. The mainly developed technologies are the dynamometer with rotational inertia as low as engine, correction method of transmitted torque error of connecting shaft by H-infinity control. Thanks to these, we achieved the capability of optimization for most of dynamic characteristics (emission, fuel consumption, drivability) on engine test bench. And we now be able to limit real vehicle test to the final tuning. As a result, we have realized new engine evaluation and optimization process.
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