Refine Your Search

Topic

Author

Search Results

Journal Article

An Application of the Particle Velocity Transfer Path Analysis to a Hybrid Electric Vehicle Motor Sound

2013-05-13
2013-01-1999
A pioneering approach to implement transfer path analysis (TPA) is proposed in this paper through applying it to an automobile. We propose to use particle velocity as a measure of TPA, in addition to using sound pressure as a conventional measure for TPA. These two quantities together will give a comprehensive and complete definition of sound. Although sound pressure is a scalar, while particle velocity is a vector, it is also proposed that the same technique of the conventional sound pressure TPA should be independently applicable to each component of particle velocity vector. This has been experimentally verified with a study on our test box system. In this paper, we apply the proposed TPA to an actual vehicle to examine its applicability, advantages and limitations. The driving motor sound of a hybrid electric vehicle is chosen as the case study. A tri-axial particle velocity sensor which also measures sound pressure at the same point is utilized in the experiment.
Technical Paper

Improved Thermal Efficiency Using Hydrous Ethanol Reforming in SI Engines

2013-09-08
2013-24-0118
The internal combustion engines waste large amounts of heat energy, which account for 60% of the fuel energy. If this heat energy could be converted to the output power of engines, their thermal efficiency could be improved. The thermal efficiency of the Otto cycle increases as the compression ratio and the ratio of specific heat increase. If high octane number fuel is used in engines, their thermal efficiency could be improved. Moreover, thermal efficiency could be improved further if fuel could be combusted in dilute condition. Therefore, exhaust heat recovery, high compression combustion, and lean combustion are important methods of improving the thermal efficiency of SI engines. These three methods could be combined by using hydrous ethanol as fuel. Exhaust heat can be recovered by the steam reforming of hydrous ethanol. The reformed gas including hydrogen can be combusted in dilute condition. In addition, it is cooled by directly injecting hydrous ethanol into the engine.
Technical Paper

Improvement of Thermal Efficiency Using Fuel Reforming in SI Engine

2010-04-12
2010-01-0584
Hydrogen produced from regenerative sources has the potential to be a sustainable substitute for fossil fuels. A hydrogen internal combustion engine has good combustion characteristics, such as higher flame propagation velocity, shorter quenching distance, and higher thermal conductivity compared with hydrocarbon fuel. However, storing hydrogen is problematic since the energy density is low. Hydrogen can be chemically stored as a hydrocarbon fuel. In particular, an organic hydride can easily generate hydrogen through use of a catalyst. Additionally, it has an advantage in hydrogen transportation due to its liquid form at room temperature and pressure. We examined the application of an organic hydride in a spark ignition (SI) engine. We used methylcyclohexane (MCH) as an organic hydride from which hydrogen and toluene (TOL) can be reformed. First, the theoretical thermal efficiency was examined when hydrogen and TOL were supplied to an SI engine.
Technical Paper

Wide-Range Air-Fuel Ratio Sensor, 1986

1986-02-01
860409
The oxygen ion conductive solid electrolyte cell served as a device for measuring the combustibles content and the oxygen content of an exhaust gas. The cell is comprised of a tubular electrolyte, two opposed electrodes and a porous diffusion layer located on the outer electrode surface. The sensor is employed to measure both rich and lean air fuel ratio through the use of an electronic circuit pumping the oxygen ions to achieve a constant voltage between the electrodes. The wide range detecting capability makes it particularly attractive for air fuel ratio control applications associated with the internal combustion engine. The result of the performance tests are as follows, Detecting range (air excess ratio λ) : 0.8 - “∞ Step response time constant (63%) : 200ms Warm up time. - less than 80 sec at 20°C We found in the durability test concerned with the heat cycle and contamination that if initial aging treatment is applied the output variation ratio (. λ/λ) is limited with in : 5%.
Technical Paper

Wide-Range Air-Fuel Ratio Sensor, 1989

1989-02-01
890299
The detection range of an air-fuel ratio sensor is expanded in the rich A/F region. Using a simulation technique, the limiting cause of the detection range in the rich A/F region is identified as insufficient combustion rates of CO and H2 with O2 on the electrode, which prevent realization of a limited diffusion state which is necessary to detect the air-fuel ratio. Applying an improved diffusion layer to decrease the diffusion rates and an improved electrode to increase the combustion rates, it is demonstrated that the detection limit can be expanded to λ=0.6 while that of a conventional sensor is λ=0.8.
Technical Paper

A Study of Friction Characteristics of Continuously Variable Valve Event & Lift (VEL) System

2006-04-03
2006-01-0222
A continuously variable valve event and lift (VEL) system, actuated by oscillating cams, can provide optimum lift and event angles matching the engine operating conditions, thereby improving fuel economy, exhaust emission performance and power output. The VEL system allows small lift and event angles even in the engine operating region where the required intake air volume is small and the influence of valvetrain friction is substantial, such as during idling. Therefore, the system can reduce friction to lower levels than conventional valvetrains, which works to improve fuel economy. On the other hand, a distinct feature of oscillating cams is that their sliding velocity is zero at the time of peak lift, which differs from the behavior of conventional rotating cams. For that reason, it is assumed that the friction and lubrication characteristics of oscillating cams may differ from those of conventional cams.
Technical Paper

Air-Fuel Ratio Sensor Utilizing Ion Transportation in Zirconia Electrolyte

1991-02-01
910501
To detect an air-fuel ratio in wide range is very important to control the automotive engines with low fuel consumption and low exhaust emissions. Although the application of zirconia electrolyte for this purpose has been proposed by the authors several years ago, there remained several problems due to the contamination of gas diffusion apertures which are exposed to the exhaust gas environment. Here the behavior of ions transported in zirconia electrolyte have been analyzed to optimize the structure and characteristics, and to guarantee the long life operation of sensor. Gas contents and their reactions in combustion process under the wide range air-fuel ratio have been analyzed, and these results were reflected to the analysis of ion transportation in zirconia electrolyte. Experimental results supported the analytical results, and they showed the possibilities of long life operation of zirconia air-fuel ratio sensor utilizing ion transportation phenomena.
Technical Paper

Real Time Control for Fuel Injection System with Compensating Cylinder-by-Cylinder Deviation

1990-02-01
900778
We have examined a new precise control method of the air fuel ratio during a transient state which provides improved exhaust characteristics of automobile engines. We investigated the measurement method for the mass of fresh air inducted by the cylinder, which is most important for controlling the air fuel ratio. The mass of fresh air must be measured in real time because it changes in each cycle during a transient state. With an conventional systems, it has been difficult to get accurate measurement of this rapidly changing mass of fresh air. The method we studied measures the mass of fresh air by using the intake manifold pressure and air flow sensors. During a transient state, the reverse flow of the residual gas from the cylinder into the intake manifold, which occurs at the first stage of the suction stroke, changes with each cycle. The mass of fresh air changes accordingly.
Technical Paper

Development of a Highly Accurate Air-Fuel Ratio Control Method Based on Internal State Estimation

1992-02-01
920290
A fuel injection control method is developed in which the transient air-fuel ratio is accurately controlled by an internal state estimation method with dynamic characteristics. With conventional methods the air-fuel ratio control precision is limited, because the air measurement system, the air and the fuel dynamic characteristics lack precision. In this development, the factors disturbing the air-fuel ratio under transient conditions are determined by analysis of the control mechanisms. The disturbance factors are found to be (1) the hot wire sensor has a delay time, (2) manifold air charging causes an overshoot phenomenon, (3) there is a dead time between sensing and fuel flow into the cylinder and (4) there is a delay of fuel flow into the cylinder caused by the fuel film. Compensation schemes are constructed for each of these technical problems.
Technical Paper

An Automatic Parameter Matching for Engine Fuel Injection Control

1992-02-01
920239
An automatic matching method for engine control parameters is described which can aid efficient development of new engine control systems. In a spark-ignition engine, fuel is fed to a cylinder in proportion to the air mass induced in the cylinder. Air flow meter characteristics and fuel injector characteristics govern fuel control. The control parameters in the electronic controller should be tuned to the physical characteristics of the air flow meter and the fuel injectors during driving. Conventional development of the engine control system requires a lot of experiments for control parameter matching. The new matching method utilizes the deviation of feedback coefficients for stoichiometric combustion. The feedback coefficient reflects errors in control parameters of the air flow meter and fuel injectors. The relationship between the feedback coefficients and control parameters has been derived to provide a way to tune control parameters to their physical characteristics.
Technical Paper

Cold Start HC Reduction with Feedback Control Using a Crank Angle Sensor

2008-04-14
2008-01-1010
Emission regulations continue to be strengthened, and it is important to decrease cold start hydrocarbon concentrations in order to meet them, now and in the future. The HC concentration in engine exhaust gas can be reduced by optimizing the air-fuel ratio. However, a conventional air-fuel ratio feedback control does not operate for the first ten seconds after the engine has started because the air-fuel ratio sensor has not yet been activated. In this paper, we report on a study to optimize the air-fuel ratio using a crank angle sensor until the air-fuel ratio sensor has been activated. A difference in fuel properties was used as a typical disturbance factor. The control was applied to both a direct-injection engine (DI) and a port-injection engine (MPI). It was evaluated for two fuel types: one which evaporates easily and one which does not. The experimental results show the air-fuel ratio is optimized for both types of fuel.
Technical Paper

A Urea-Dosing Device for Enhancing Low-Temperature Performance by Active-Ammonia Production in an SCR System

2008-04-14
2008-01-1026
A new urea-dosing device with an active-ammonia production function was developed. This function is achieved by an electrically heated bypass passage with a hydrolysis catalyst for urea-to-ammonia conversion. The new device also has the function of mixing ammonia and exhaust gas. It is compact and has low-pressure loss by using the vortex occurring at the back of a static vane. We built a trial device for a small diesel engine and obtained steady state and transient data. The heated-bypass concept can be used in the aftertreatment system of passenger cars. Although active-ammonia production consumes electric power, a predictive calculation of power consumption (based on experimental results) shows that the developed bypass heater can suppress the energy consumption enough not to harm the high-energy efficiency of diesel engines.
Technical Paper

Air Fuel Ratio Sensor and Its Signal Processing Module

1993-03-01
930232
This report describes the development of an air fuel ratio sensor with a linear voltage output, and its signal processing module that is able to calibrate the sensor output function on the measuring point of the 20.9% oxygen concentration in atmospheric air and the zero diffusion current at stoichiometry as the reference. This sensing system is effective when applied to air fuel ratio PID feed back engine control and it is able to realize the reduction of initial variability of sensors, interchangeability of sensors, and long term output change of the sensor.
Technical Paper

NOx Conversion Properties of a Mixed Oxide Type Lean NOx Catalyst

2000-03-06
2000-01-1197
Development is proceeding on catalysts which separate the NOx in lean exhaust gas by adsorption and then reduce the adsorbed NOx in combustion exhaust gas with the stoichiometric or a slightly richer air fuel ratio, as well as exhaust conversion technology that uses these catalysts. Amidst this research it has been found that catalysts containing mixed metal oxides exhibit superior NOx adsorption performance, so the authors prepared a mixed metal oxide catalyst by adding precious metals and promoters, etc. The resulting catalyst has high heat resistance and also offers excellent SOx durability. These properties were presumed to be due to an adsorbent including the mixed metal oxide, and the relation between the physical properties and NOx conversion properties of the catalyst was investigated.
Technical Paper

Air/Fuel Ratio Control Using Upstream Models in the Intake System

1999-03-01
1999-01-0857
Generalized models of the air/fuel ratio control using estimated air mass in the cylinder were presented to obtain highly accurate control during transient conditions in high supercharged direct injection systems with a complex air induction system. The air mass change was estimated by using upstream models which estimated the pressure of the intake manifold by introducing the output of the air flow meter and the differential of the output into aerodynamic equations of the intake system. The air mass into the cylinders was estimated at the beginning of the intake stroke under a wide range of driving conditions, without compensating for changes in the downstream parameters of the intake system and engine. Therefore, the upstream models required relatively minor calibration changes for each engine modification to be able to estimate the air mass on a cylinder-by-cylinder basis.
Technical Paper

A Model-Based Technique for Spark Timing Control in an SI Engine Using Polynomial Regression Analysis

2009-04-20
2009-01-0933
Model-based methodologies for the engine calibration process, employing engine cycle simulation and polynomial regression analysis, have been developed and the reliability of the proposed method was confirmed by validating the model predictions with dynamometer test data. From the results, it was clear that the predictions by the engine cycle simulation with a knock model, which considers the two-stage hydrocarbon ignition characteristics of gasoline, were in good agreement with the dynamometer test data if the model tuning parameters were strictly adjusted. Physical model tuning and validation were done, followed by the creation of a dataset for the regression analysis of charging efficiency, EGR mass, and MBT using a 4th order polynomial equation. The stepwise method was demonstrated to yield a logarithm likelihood ratio and its false probability at each term in the polynomial equation.
Technical Paper

An Air-Fuel Ratio and Ignition Timing Retard Control Using a Crank Angle Sensor for Reducing Cold Start HC

2009-04-20
2009-01-0588
Emission regulations continue to be strengthened, and it is important to decrease cold start hydrocarbon concentrations in order to meet them, now and in the future. The HC concentration in engine exhaust gas is reduced by controlling the air-fuel ratio to the low HC range and retarding the ignition timing as much as possible until the engine stability reaches a certain deterioration level. Conventionally however, the target air-fuel ratio has been set at a richer range than the low HC range and the target ignition timing has been more advanced than the engine stability limit, in order to stabilize the engine for various disturbances. As a result, the HC concentration has not been minimized. To solve this problem, a new engine control has been developed. This control uses a crank angle sensor to simultaneously control the air-fuel ratio and the ignition timing so that the HC concentration can be minimized.
Journal Article

Development of a New Metal Substrate for Lean NOx Trap

2008-04-14
2008-01-0806
This paper presents a new substrate for Lean NOx Traps (LNT) which enables high NOx conversion efficiency, even after long-term aging, when using alkali metals as the NOx adsorber. When a conventional metal honeycomb is used as the LNT substrate, the chromium in the metal substrate migrates into the washcoat and reacts with the alkali metals after thermal aging. In order to help prevent this migration, we have developed a new substrate where a fine -alumina barrier is precipitated to the surface of the metal substrate. The new substrate is highly capable of preventing migration of chromium into the washcoat and greatly enhances the NOx conversion. The durability of the new substrate and emission test using a test vehicle are also examined.
Technical Paper

Study on Mixture Formation and Ignition Process in Spark Ignition Engine Using Optical Combustion Sensor

1990-09-01
901712
Mixture formation and the ignition process in 4 cycle 4 cylinder spark ignition engines were investigated, using an optical combustion sensor that combines fiber optics with a conventional spark plug. The sensor consists of a 1-mm diameter quartz glass optical fiber cable inserted through the center of a spark plug. The tip of the fiber is machined into a convex shape to provide a 120-degree view of the combustion chamber interior. Light emitted by the spark discharge between spark electrodes and the combustion flames in the cylinder is transmitted by the optical cable to an opto-electric transducer. As a result, the ignition and combustion process which depends on the mixture formation can be easily monitored without installing transparent pistons and cylinders. This sensor can give more accurate information on mixture formation in the cylinders.
Technical Paper

A New Engine Control System Using Direct Fuel Injection and Variable Valve Timing

1995-02-01
950973
A new engine drivetrain control system is described which can provide a higher gear ratio and leaner burning mixture and thus reduce the fuel consumption of spark ignition engines. Simulations were performed to obtain reduced torque fluctuation during changes in the air - fuel ratio and gear ratio, without increasing nitrogen oxide emissions, and with minimum throttle valve control. The results show that the new system does not require the frequent actuation of throttle valves because it uses direct fuel injection, which increases the air - fuel ratio of the lean burning limit. It also achieves a faster response in controlling the air mass in the cylinders. This results in the minimum excursion in the air - fuel ratio which in turn, reduces nitrogen oxide emissions.
X