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Technical Paper

Engine Application of a Battery Voltage-Driven DI Fuel Injection System

Every fuel injection system for DI gasoline engines has a DC-DC converter to provide high, stabile voltage for opening the injector valve more quickly. A current control circuit for holding the valve open is also needed, as well as a large-capacity capacitor for pilot injection. Since these components occupy considerable space, an injector drive unit separate from the ECU must be used. Thus, there has been a need for a fuel injection system that can inject a small volume of fuel without requiring high voltage. To meet that need, we have developed a dual coil injector and an opening coil current control system. An investigation was also made of all the factors related to the dynamic range of the injector, including static flow rate, fuel pressure, battery voltage and harness resistance. Both efforts have led to the adoption of a battery voltage-driven fuel injector.
Technical Paper

The Development of Driveability Index and the Effects of Gasoline Volatility on Engine Performance

To reduce engine exhaust emissions, we have had to deal with this global environmental problem from the fuel side by introducing oxygenated fuels, reducing the RVP and using low aromatics. But when we change the fuel components and distillation, we must take note about how these affect the engine driveability. We have used T50, T90, RVP and so on as the fuel index up to the present. It is possible to characterize the fuel from one aspect, but these indexes don't always represent the real feature of the fuel. In this paper we propose a New Driveability Index (here in after referred to as NDI) that is more realistic and accurate than the other fuel indexes. We used a 1600cc DOHC L4 MPI type engine. We used Model Gasolines and Market Gasolines, see Appendix(1), (2) and (3), and tested them according to the Excess Air Ratio Response Test Method (here in after referred to as λ-R Test) that was suggested in SAE paper #930375, and we calculated the NDI statistically.
Technical Paper

Joint PAJ/JAMA Project - Development of a JASO Gasoline Bench Engine Test for Measuring CCDs

Detergent additives in automotive gasoline fuel are mainly designed to reduce deposit formation on intake valves and fuel injectors, but it has been reported that some additives may contribute to CCD formation. Therefore, a standardized bench engine test method for CCDs needs to be developed in response to industry demands. Cooperative research between the Petroleum Association of Japan (PAJ) and the Japan Automobile Manufacturers Association, Inc. (JAMA), has led to the development of a 2.2L Honda engine dynamometer-based CCD test procedure to evaluate CCDs from fuel additives. Ten automobile manufacturers, nine petroleum companies and the Petroleum Energy Center joined the project, which underwent PAJ-JAMA round robin testing. This paper describes the CCD test development activities, which include the selection of an engine and the determination of the optimum test conditions and other test criteria.
Technical Paper

Development of a New Compound Fuel and Fluorescent Tracer Combination for Use with Laser Induced Fluorescence

Laser induced fluorescence (LIF) is a useful method for visualizing the distribution of the air-fuel ratio in the combustion chamber. The way this method is applied mainly depends on the fluorescent tracer used, such as biacetyl, toluene, various aldehydes, fluoranthene or diethylketone, among others. Gasoline strongly absorbs light in the UV region, for example, at the 248-nm wavelength of broadband KrF excimer laser radiation. Therefore, when using this type of laser, iso-octane is employed as the fuel because it is transparent to 248-nm UV light. However, since the distillation curves of iso-octane and gasoline are different, it can be expected that their vaporization characteristics in the intake port and cylinder would also be different. The aim of this study was to find a better fuel for use with LIF at a broadband wavelength of 248 nm. Three tasks were undertaken in this study.
Technical Paper

Development of an Electric Concept Vehicle with a Super Quick Charging System

Recent environmental concerns such as atmospheric pollution and energy conservation have intensified the need to develop pollution-free, energy-efficient vehicles. One such solution is the electric automobile which draws its power from rechargeable batteries. There are few vehicles on the road today because present batteries can store very little energy compared with that of a tank of gasoline. To obtain adequate range, this concept vehicle adopts a new battery which can be recharged to 40% of capacity in six minutes. This super quick charging system makes it possible to recharge the batteries at an electric recharging station just as gasoline-powered vehicles are refilled at service stations. The electric concept vehicle also has improved aerodynamics, reduced rolling resistance and a lighter curb weight, which help to assure adequate range.
Technical Paper

Effects of NOx and Unburned Gasoline on Low Temperature Sludge Formation in Engine Oil

It is generally known that NOx reacts with unburned gasoline, olefins in particular, to form sludge precursors. In this study, the authors investigated the process by which NOx and unburned gasoline mix into the engine oil and analyzed the mechanism whereby stop and go driving accelerates sludge formation. It has been found that NOx detected in the engine oil as nitrite ions mixes into the oil in the crankcase. The NOx concentration in the engine oil increases rapidly when the crankcase gas temperature is nearly equal to the dew point of the water vapor in the crankcase. Unburned gasoline is mainly absorbed into the oil through the oil film on the cylinder walls and the oil in the ring grooves. During low-temperature engine operation in stop-go driving (i.e., when the vehicle is stopped), NOx and unburned gasoline are absorbed into the engine oil and, in high-temperature engine operation (i.e., when the vehicle is moving), NOx and unburned gasoline are released from the oil.
Technical Paper

Development of Four Cylinder SR Engine

The SR engine is a new medium-size, all aluminum (cylinder block, head, rocker cover and oil pan) in-line 4-cylinder gasoline powerplant developed as a replacement for CA engine in Nissan's compact passenger cars. The development aim set for this engine was to achieve excellent power output and ample torque in the middle-and high-speed ranges, as well as a clear, linear engine sound up to the red zone. These performance targets have been achieved through the use of the 4-valve-per-cylinder DOHC design featuring a Y-shaped valve rocker arm system. This system allows a straight intake port for high power output and a narrow valve angle for a compact combustion chamber. The result is ample torque output as well as good fuel economy.
Technical Paper

An Analytical Study on Knocking Heat Release and its Control in a Spark Ignition Engine

In this study the relationship between the timing for the onset of autoignition and the amount of mixture fraction burned by autoignition and the resulting knock intensity is investigated using a combination of high-speed laser shadowgraphy and thermodynamic calculations. It is made clear that over 40 percent of the entire mixture burns due to autoignition in a crank angle of less than five to eight degrees when an engine is operated under a heavy knocking condition. This burn rate is about ten times higher than that of combustion seen in a normally propagating flame. This abrupt heat release causes an oscillation in cylinder gases, resulting in a knocking sound. The experimental procedure is applied to examine the effect of a squish combustion chamber on suppressing knock. The results indicate that, when autoignition occurs in the squish area, an amount of mixture burned by autoignition is small, resulting in lower knock intensity.
Technical Paper

Individual Cylinder Knock Control by Detecting Cylinder Pressure

To improve available power, tolerance to variation in fuel octane number and high engine speed knock control, an individual cylinder knock control has been developed. Knock are detected by spark plug washer transducers. Which indicate individual cylinder pressures. Last year we read a paper entitled “Cylinder Pressure Vibration Analysis Indicates Accurate Knock Detection”. We read continuously on the following items. Spark plug washer transducers - These are piezoelectric ceramic rings which fit beneath individual spark plugs. These can detect knock at high engine speed, and are very durable. Knock detection and control algorithm - Knock is indicated by the transducer's cylinder pressure vibration signal. When knock occurs in the cylinder, the ignition timing of the cylinder is controlled. During the transient condition, control response is fast by learning control. Fail safe - At transducer trouble, the ignition timing of the cylinder is controlled by other transducer signals.
Technical Paper

Effect of Gasoline Composition on Engine Performance

In order to clarify the effect of each gasoline component on engine performance during warm-up, changes in the air-fuel ratio and quantity of wall flow (liquid gasoline on the induction port) were measured using ordinary gasolines and model gasolines consisting of a blend of several hydrocarbons and MTBE (methyl-tertiary-butyl-ether). The unburned air-fuel mixture in a combustion chamber was sampled via a solenoid valve and analyzed by gas chromatography to investigate the vaporization rate of each component. The results show that MTBE has an important effect on driveability because it contains oxygen and easily vaporizes, resulting in a lean mixture in the transient state. The popular driveability index, T50 (50% distillation temperature), does not provide an adequate means of evaluating MTBE-blended gasoline.
Technical Paper

Effects of Clean Fuels (Reformulated Gasolines, M85, and CNG) on Automotive Emissions

With the aim of improving the air quality in large cities, the California Air Resources Board (CARB) has stipulated that non-methane organic gas (NMOG) composed of carbon numbers from C1 to C12 must be reduced for vehicle categories designated as Transitional Low Emission Vehicles (TLEVs), Low Emission Vehicles (LEVs), Ultra low Emission Vehicles (ULEVs), and Zero Emission Vehicles (ZEVs). Although considerable research work has been done on this issue to date, the entire picture is still not clear. Studies done by the authors have been aimed at providing a better understanding of the potential for reducing automotive tailpipe emissions by using several clean fuel candidates. The major questions of concern are the extent to which emissions of certain species can actually be reduced and what fuel can provide the best performance under a reduced NMOG condition.
Technical Paper

Effect of Intake Valve Deposits and Gasoline Composition on S.I. Engine Performance

Valve deposits in gasoline engines increase with time, absorbing fuel during acceleration and releasing fuel during deceleration. Valve deposits insulate the heat release from the cylinder and this phenomenon is the cause of bad fuel vaporization. In this way, the deposits greatly affect the driveability and exhaust emissions. Using a 3.OL MPI(Multipoint Injection) engine, we measured the quantity of fuel that deposits at the intake port, and the throttle response (using a wall-flow meter made by Nissan Motor Co.1), 2) to study the deposits effect on driveability and exhaust emissions at a low temperature. The deposits were formed on the intake valve surface (about 8.0 on the CRC deposit rating scale) through 200 hours of laboratory engine stand operation. At low temperature, C9 and C10 hydrocarbons tend to stick to the intake port surface and intake valve as “wall-flow”; this is one cause of bad driveability.
Technical Paper

Numerical Simulation System for Analyzing Fuel Film Flow in Gasoline Engine

A new numerical simulation system has been developed which predicts flow behavior of fuel film formed on intake port and combustion chamber walls of gasoline engines. The system consists of a film flow model employing film thickness as a dependent variable, an air flow model, and a fuel spray model. The system can analyze fuel film flow formed on any arbitrary three-dimensional configuration. Fuel film flow formed under a condition of continuous intermittent fuel injection and steady-state air flow was calculated, and comparison with experimental data showed the system possessing ability of qualitative prediction.
Technical Paper

Effect of Catalyst Systems on Characteristics of Exhaust Hydrocarbon Species

The California Low-Emission Vehicle (LEV) standards mandate a reduction in non-methane organic gases (NMOG). With the aim of analyzing NMOG emissions, a comparison was made of the hydrocarbon species found in the exhaust gas when different types of catalyst systems and fuel specifications were used. NMOG emissions are usually measured by removing methane from the total hydrocarbon (THC) emissions and adding aldehyde and ketone emissions. The NMOG level found in this way is thus influenced by the rate of methane in THC emissions. Another important factor in the LEV standards is specific reactivity (SR), indicating the formation potential of ozone, which is one cause of photochemical smog. Specific reactivity is expressed by the amount of ozone generated per unit weight of NMOG emissions, and is affected by the respective proportion of hydrocarbon species in the total NMOG emissions.
Technical Paper

New PM Valve Seat Insert Materials for High Performance Engines

Internal combustion engines experience severe valve train wear and the reduction of valve seat and seat insert wear has been a long-standing issue. In this work, worn valve seats and inserts were examined to obtain a fundamental understanding of the wear mechanisms and the results were applied in developing new valve seat insert materials. The new exhaust valve insert material for gasoline engines is a sintered alloy steel containing Co-base hard particles, with lead infiltrated only for inserts used in unleaded gasoline engines. The new intake valve insert material for gasoline engines is a high-Mo sintered steel, obtained through transient liquid phase sintering and with copper precipitated uniformly. This material can be used for both leaded and unleaded gasoline engines. Valve and valve seat insert wear has long been an issue of concern to engine designers and manufacturers.
Technical Paper

An Analysis of Wall Flow and Behavior of Fuel in Induction Systems of Gasoline Engines

The transient performance of an engine generally depends on the volume of wall flow and behavior of fuel in the induction system which is composed of the intake manifold and the intake port. An experimental technique has been developed for estimating these phenomena in a gasoline engine, which employs a meter for measuring the air-fuel mixture ratio. Using this technique we analyzed single point and multipoint injection systems, and determined the differences in the volume of fuel associated with wall flow. The effects of the shape and specifications of fuel supply system components on the volume of wall flow and fuel behavior in these systems were also made estublished.
Technical Paper

The New Nissan 1.7 Liter 4 Cylinder Diesel Engine

The new Nissan 1.7 liter 4 cylinder diesel engine has been developed to meet the social requirements for energy conservation. The main objective was to improve fuel economy without sacrificing driveability, and this has been achieved by minimizing engine weight, reducing mechanical friction loss and optimizing the combustion system. The CA series gasoline engine, which is known for its light weight, was chosen as the base engine for dieselization. The swirl chamber combustion system used for the LD28 engine was modified to satisfy the requirements for high power, good fuel economy and low noise. Engine noise has been reduced with the aid of several analytical methods such as laser holography. Special attention has been paid to the reduction of diesel knock which is most offensive to the ear. To install this engine in a small FWD vehicle transversely, much effort went into the minimizing of the engine length and width.
Technical Paper

Crank-angle-resolved Measurements of Air-fuel Ratio, Temperature, and Liquid Fuel Droplet Scattering in a Direct-injection Gasoline Engine

Simultaneous crank-angle-resolved measurements of gasoline vapor concentration, gas temperature, and liquid fuel droplet scattering were made with three-color infrared absorption in a direct-injection spark-ignition engine with premium gasoline. The infrared light was coupled into and out of the cylinder using fiber optics incorporated into a modified spark plug, allowing measurement at a location adjacent to the spark plug electrode. Two mid-infrared (mid-IR) laser wavelengths were simultaneously produced by difference-frequency-generation in periodically poled lithium niobate (PPLN) using one signal and two pump lasers operating in the near-infrared (near-IR). A portion of the near-IR signal laser residual provided a simultaneous third, non-resonant, wavelength for liquid droplet detection. This non-resonant signal was used to subtract the influence of droplet scattering from the resonant mid-IR signals to obtain vapor absorption signals in the presence of droplet extinction.
Technical Paper

A New Quasi-Dimensional Combustion Model Applicable to Direct Injection Gasoline Engine

Gasoline engines employ various mechanisms for improvement of fuel consumption and reduction of exhaust emissions to deal with environmental problems. Direct fuel injection is one such technology. This paper presents a new quasi-dimensional combustion model applicable to direct injection gasoline engine. The Model consists of author's original in-cylinder turbulence and mixture homogeneity sub model suitable for direct fuel injection conditions. Model validation results exhibit good agreement with experimental and 3D CFD data at steady state and transient operating conditions.
Technical Paper

Development of “Hybrid EPS”

Hydraulic power steering is applied for petrol and diesel models of Infinity M series to provide supreme feeling of steering. Power assist of hydraulic power steering (here after called HPS), however, does not work when hybrid vehicle is in EV drive mode because the engine, which is the power source stops and the power is not supplied. Electric Power Steering (hereafter called EPS), therefore, “MUST” be installed to assist the power. Here comes the need that Nissan has developed our Hybrid EPS for Infinity M Hybrid model to keep providing supreme feeling of steering of hydraulic power steering without huge packaging change from the standard packaging of petrol & diesel models with hydraulic power steering. Our Hybrid EPS is the 1st hybrid EPS system in the world that is effectuated by oil pressure, and succesively realized by unique and excellent technology of Nissan.