Search Results

The effects of high boiling point fuel additives on deposits were investigated in a commercial turbocharged direct injection gasoline engine. It is known that high boiling point substances have a negative effect on deposits. The distillation end points of blended fuels containing these additives may be approximately 15°C higher than the base fuel (end point: 175°C). Three additives with boiling points between 190 and 196°C were examined: 4-tert-Butyltoluene (TBT), N-Methyl Aniline (NMA), and 2-Methyl-1,5-pentanediamine (MPD). Aromatics and anilines, which may be added to gasoline to increase its octane number, might have a negative effect on deposits. TBT has a benzene ring. NMA has a benzene ring and an amino group. MPD, which has no benzene ring and two amino groups, was selected for comparison with the former two additives.

In order to adapt to energy security and the changes of global-scale environment, further improvement of fuel economy and adaptation to each country’s severer exhaust gas emission regulation are required in an automotive engine. To achieve higher power performance with lower fuel consumption, the engine’s basic internal design such as an engine block and cylinder head were changed and the combustion speed was dramatically increased. Consequently, stroke-bore ratio and valve layout were optimized. Also, both flow coefficient and intake tumble ratio port were improved by adopting a laser cladded valve seat. In addition, several new technologies were adopted. The Atkinson cycle using a new Electrical VVT (Variable Valve Timing) and new combustion technology adopting new multi-hole type Direct fuel Injector (DI) improved engine power and fuel economy and reduced exhaust emissions.

Engine friction reduction is an effective means to improve fuel consumption. Fluid friction reduction of main bearing is examined for engine friction reduction in cold condition. As one of the examinations, it was focused on low temperature of lubricating oil in the early stage during engine cold start. In hydrodynamic lubrication, the oil film temperature is maintained by balance between heat generation and heat transfer. The heat generation is generated by shear of lubricating oil. The factors of the heat transfer, the following elements are considered as follows, A) The heat transfer to a crank shaft, B) The heat transfer to a bearing, C) The heat transfer by convection. If the heat generation is constant, oil film temperature is increased by reduction of heat transfer. It is considered that the reduction of oil leakage and reduction of the heat transfer by convection is equivalent.

It is important for vehicle concept planning to estimate fuel economy and the influence of vehicle vibration in advance. This can be accomplished using virtual engine specifications and a virtual vehicle frame. In this paper, I will show the power plant model with electric starter and battery that can predict fuel economy, combustion heat results and transient torque. The power plant is a 1.3L 4cyl designed for NA Spark Ignition. The power plant model was realized using an energy based model using VHDL-AMS. Here, VHDL-AMS is modeling language stored in IEC international standard (IEC61691-6) and can realize multi physics in 1D simulation. The modeling language supports electrical, magnetic, thermal, mechanical, fluidic and compressive fluidic domains. The model was created in house using VHDL-AMS and validated on ANSYS SIMPLORER. The simulated results of fuel energy consumption agreed with driving energy and amount of energy losses, e.g. cooling loss, exhaust loss.

In response to increasing demands for measures to conserve the global environment and the introduction of more stringent CO2 emissions regulations around the world, the automotive industry is placing greater focus on reducing levels of CO2 through the development of fuel-efficient technologies. With the aim of improving fuel economy, a new continuously variable transmission (CVT) has been developed for 2.0-liter class vehicles. This new CVT features various technologies for improving fuel economy including a coaxial 2-discharge port oil pump system, wider ratio coverage, low-viscosity CVT fluid, and a flex start system. This CVT is also compatible with a stop and start (S&S) system that reduces fuel consumption by shutting off the engine while the vehicle is stopped. In addition, the development of the CVT improves driveability by setting both the driving force and engine speed independently.

Improving the engine efficiency to respond to climate change and energy security issues is strongly required. In order to improve the engine efficiency, lower fuel consumption, and enhance engine performance, OEMs have been developing high compression ratio engines and downsized turbocharged engines. However, higher compression ratio and turbocharging cause cylinder pressure to increase, which in turn increases the demand voltage for ignition. To reduce the demand voltage, a new ignition system is developed that uses a high voltage Zener diode to maintain a constant output voltage. Maintaining a constant voltage higher than the static breakdown voltage helps limit the amount of overshoot produced during the spark event. This allows discharge to occur at a lower demand voltage than with conventional spark ignition systems. The results show that the maximum reduction in demand voltage is 3.5 kV when the engine is operated at 2800 rpm and 2.6 MPa break mean effective pressure.

At the engine restart, when the temperature of the catalytic converter is low, additional fuel consumption would be required to warm up the catalyst for controlling exhaust emission.The aim of this study is to find a thermally optimal way to reduce fuel consumption for the catalyst warm up at the engine restart, by improving the thermal retention of the catalytic converter in the cool down process after the previous trip. To make analysis of the thermal flow around the catalytic converter, a 2-D thermal flow model was constructed using the thermal network method. This model simulates the following processes: 1) heat conduction between the substrate and the stainless steel case, 2) heat convection between the stainless steel case and the ambient air, 3) heat convection between the substrate and the gas inside the substrate, 4) heat generation due to chemical reactions.

Fuel efficiency improvement measures are focusing on both cold and hot conditions to help reduce CO2 emissions. Recent technological trends for improving fuel economy such as hybrid vehicles (HVs), engine start and stop systems, and variable valve systems feature expanded use of low-temperature engine operation regions. Under cold conditions (oil temperature: approximately 30°C), fuel consumption is roughly 20% greater than under hot conditions (80°C). The main cause of the increased friction under cold conditions is increased oil viscosity. This research used the motoring slipping method to measure the effect of an improved crankshaft bearing, which accounts for a high proportion of friction under cold conditions. First, the effect of clearance was investigated. Although increasing the clearance helped to decrease friction due to the oil wedge effect, greater oil leakage reduced the oil film temperature increase generated by the friction.

From the time the first Hybrid Vehicle (HV) was launched, 17 years have past, and HV vehicles have boosted the global CO2 reduction trend. In order to maximize their merit, many HV engines focused on the best fuel consumption value namely thermal efficiency. This was because HV systems can control the operating area of engine and get merit. However, considering climate change and energy issues, it is important to focus conventional vehicle as well as HV vehicle progress. The Atkinson cycle with a high compression ratio is the typical approach that HV engines use to enhance thermal efficiency. However, the drawback of the high compression ratio is a reduction of engine torque. Thermal efficiency at low load areas is relatively more important with conventional engines than with HV engines and how to overcome these issues is significantly important with conventional engines.

Due to increasing demands for further CO2 reduction and tighter exhaust emissions regulations, automakers are increasingly downsizing turbo-charged diesel engines by raising specific power, or adopting low-pressure loop exhaust gas recirculation (LPL-EGR) systems to improve the EGR rate. However, adopting a higher boost pressure to increase the specific power, or introducing hot exhaust gas before the turbocharger compressor with the LPL-EGR system creates higher gas temperatures in the compressor, which results in soot-containing deposits derived from the engine oil in the compressor. This phenomenon causes significant deterioration of turbocharger efficiency. Therefore, countermeasures such as restricting boost pressure or limiting EGR usage in the operational map are necessary to prevent engine performance deterioration. Increasing the gas temperature in the compressor while preventing deposit formation should enable further improvements in fuel consumption and engine power.

Previous reports have already described the details of engine start-shock and the mechanism of vibration mechanism in a stationary vehicle. This vibration can be reduced by optimized engine and motor generator vibration-reduction controls. A prediction method using a full-vehicle MBD model has also been developed and applied in actual vehicle development. This paper describes the outline of a new method for the hybrid system of mechanical power split device with two motors that predicts engine start-shock when the vehicle is accelerating while the engine is stopped. It also describes the results of mechanism analysis and component contribution analysis. This method targets engine start-shock caused by driving torque demand during acceleration after vehicle take-off. The hybrid control system is modeled by MATLAB/Simulink. A power management and motor generator control program used in actual vehicles is installed into the main part of the control system model.

The development of the Lexus LFA focused on the pursuit of a passionate driving experience suitable for a super sports car. The shift speed control system in the LFA is an automated manual transmission (AMT) that uses an electrohydraulic actuator. The excellent shifting performance of the AMT was achieved by developing control technology that performs smooth, quick, and highly responsive shifting in accordance with the driving conditions. This was the result of repeated evaluations in both normal driving and on circuits featuring many acceleration, deceleration, and high-speed driving sectors. This paper describes the AMT shift speed control system and technology.

This paper describes an outline of the Toyota FCHV-adv, a fuel cell vehicle with a practical cruising range of more than 500 km. The cold startability of the FCHV-adv was improved by modifying the FC stack and control system. As a result, the FCHV-adv is capable of starting at a temperature of -30°C. In the future, Toyota intends to improve durability and reduce costs and is continuing to cooperate with governments and energy businesses to establish infrastructure and make the necessary modifications to laws and regulations.

In this study, we combined a diesel engine with the Toyota Hybrid System (THS). Utilizing the functions of the THS, reducing engine friction, lowering the compression ratio, and adopting a low pressure loop exhaust gas recirculation system (LPL-EGR) were examined to achieve both low fuel consumption and low nitrogen oxides (NOx) emissions over a wide operating range. After applying this system to a test vehicle it was verified that the fuel economy greatly surpassed that of a conventional diesel engine vehicle and that NOx emissions could be reduced below the value specified in the Euro 6 regulations without DeNOx catalysts.

The effects of Hydrotreated vegetable oil (HVO) on combustion and emission characteristics in a diesel engine were investigated by using spray analyzer, engine dynamometer and vehicle tests. Spray analysis showed that spray characteristics was virtually the same for HVO and diesel. From the results of the engine dynamometer and the vehicle tests, it was found that the high cetane number and the zero aromatics of HVO could reduce in HC and PM emissions. Moreover, as a result of optimized engine calcification, HVO is capable of improving partial fuel consumption and full-load torque. These results indicate that HVO has beneficial fuel characteristics for diesel engine.

This paper describes the development of a High Speed Calculation Diesel Combustion Model that predicts combustion-related behaviors of diesel engines from passenger cars. Its output is dependent on the engine's operating parameters and on input from on-board pressure and temperature sensors. The model was found to be capable of predicting the engine's in-cylinder pressure, rate of heat release, and NOx emissions with a high degree of accuracy under a wide range of operating conditions at a reasonable computational cost. The construction of this model represents an important preliminary step towards the development of an integrated Model Based Control system for controlling combustion in diesel engines used in passenger cars.

Achieving the speed and performance of a true supercar was merely the starting point of this development. In addition, the development also focused on achieving emotive performance attributes to enhance driver appeal. For this the engine was developed to assist a vehicle handling provides unsurpassed response, the creating a feeling of infinite acceleration potential, response is instantaneous and based on close understanding of driver's reactions and Awe inspiring sound is providing. It meets the latest emission standard Euro V and achieves good fuel consumption with a wide range stoechiometric air fuel ratio, till speeds up to 240km/h.

It may be possible to simplify the structure and control systems of a lithium-ion battery by replacing the conventional liquid electrolyte with a solid electrolyte, resulting in higher energy density. However, power performance is a development issue of batteries using a solid electrolyte. To increase battery power performance, in addition to lithium ionic conductivity within the bulk of the electrolyte, it is also necessary to boost the lithium ionic conductivity at the interface between the electrode active material and the electrolyte, and to boost electron and lithium ionic conductivity within the cathode and anode active material. This research studied the mechanism of resistance reduction by electrode surface modification. Subsequently, this research attempted to improve electron conductivity by simultaneously introducing oxygen vacancies and carrying out nitrogen substitution in the crystalline structure of the Li4Ti5O12 anode active material.

The outline of the TOYOTA FCHV-adv is described in this paper. The TOYOTA FCHVadv achieved an approximately 25 percent improvement in vehicle fuel efficiency and about 1.9 times the amount of usable hydrogen in comparison with the previous model. These improvements have enabled almost 2.5 times longer practical cruising range, more than 500 km. The freeze start capabilities of the FCHV-adv were improved by modifying the FC stack and control system. As a result, the FCHV-adv has been capable of starting at a temperature of -30°C. In the future, TOYOTA intends to improve durability and reduce costs.

In order to reduce CO2, EV and Hybrid Vehicle (HV) are effective. Those type vehicles have different power train from conventional vehicle. Those new power trains drastically improve their efficiency from conventional vehicle with keeping same or superior power performance. On the other hand, those vehicles have the issue for thermal energy shortage during warming up process. The thermal energy is very large. The thermal energy seriously affect on the fuel economy for HV and the mileage for EV. In this paper, the power performance, the fuel economy and the effect of heat energy recovery from the exhaust gas are discussed for HV. For the power performance, the simulated acceleration time of 0-100km/h was 11.8sec and the measured vehicle time was 11.9sec. The error between simulation and actual measurement result was 1.2%. As for the fuel economy, the energy management using exhaust gas heat exchange system improved 10.3% of the fuel consumption during warming up.