Browse Topic: Stratified charge engines

Items (56)

A Review of Ultra-lean and Stratified Charged Combustion in Natural Gas Spark Ignition Engines

03/15/2023

Natural gas (NG) can be compressed to a high pressure of around 200 bar for use in engines and other applications. Compressed natural gas (CNG) contains 87–92% methane (CH4) and has a low carbon-to-hydrogen ratio compared to other hydrocarbon (HC) fuels. Due to this, it can potentially reduce carbon dioxide (CO2) emissions by more than 20% compared to conventional fuels like diesel or gasoline. This makes CNG one of the most environmentally friendly fuels for internal combustion engines (ICEs). To improve the thermal efficiency of ICEs, higher compression ratios (CRs) and leaner combustion are essential. Since CNG is a gaseous fuel, it has several advantages over liquid fuels due to its favorable physical and chemical properties. A few of these advantages are minimal fuel evaporation issues, a low-carbon content in the fuel composition and a high-octane number. The CNG high-octane number allows for a high CR, resulting in higher thermal efficiency and lower emissions. It should be

Ziyaei, Siyamak, Mazlan, Siti Khalijah, Lappas, Petros

In-Cylinder Charge Stratification and Fuel-Air Mixing in a New, Low-Emission, Two-Stroke Engine

35-8-3-27106/01/2007

A new air-assisted injection system-based, two-stroke engine has been developed at the Indian Institute of Science, Bangalore over the past few years and shows the potential to meet emission norms such as Euro II and Euro III and yet deliver satisfactory performance. The 70 cc engine works on the direct mixture injection principle with scavenging performed by air alone instead of an air-fuel mixture. A small 20 cc pump driven off the engine is used for mixture preparation prior to in-cylinder injection of the mixture. In the present study, the mixture injection and subsequent charge stratification process inside the engine cylinder is modeled. A three-dimensional compressible flow code with a standard k-ε turbulence model with wall functions is developed and used for this modelling. To account for the moving boundary or piston in the engine cylinder domain, a non-stationary and deforming grid is used in this region with stationary cells in the ports and connecting ducts. A flux

Bakshi, S., Anand, T., Ravikrishna, R.

Direct-injection resurgence

AUTOJAN05_0201/01/2005

The Japanese OEMs are integrating the latest-generation technology into their newest gasoline and diesel engines, focusing the latter on export markets such as Europe. Japan's direct-injection gasoline (DIG) engine movement, at one time touted to be champion of power and fuel economy, may have appeared to have slowed but has not. There are still many vehicles powered by a variety of DIG powerplants. Nissan has the most, comprising direct-injection versions of the QR inline four-cylinder and the VQ V6, all identified with the suffix DD. Mitsubishi suffered from its overly zealous GDI (gasoline direct-injection) drive, turning almost all of its gasoline engines to the specification. The beleaguered manufacturer has persevered, offering some GDI models while readying the improved second-generation version. The DIG movement is now gathering renewed momentum. Toyota and Honda now offer two new cars powered by their latest direct-injection gasoline engines of uniquely different

Yamaguchi, Jack

Reduction of Exhaust Gas Emission in a Two-Stroke Engine with Pneumatic Fuel Injection

2002-01-216807/09/2002

In this article possibilities of fuel injection control in two-stroke engines are presented. This is a low cost in-cylinder fuel injection system for stratified charge engines according to idea of Professor Stanislaw Jarnuszkiewicz with modified system of gases movement organization, that is much simpler than alternatives. The authors modified this pneumatic fuel injection system by means of hot exhaust gases drawn from one cylinder during the working stroke and, following the addition of fuel, forced into another cylinder during the compression stroke. Spraying and injection of fuel by means of hot exhaust gases give additional possibilities of complete evaporation of light fuels, alternative fuels with extended fraction and heavier fuels, such as diesel oil, kerosene and vegetable oil. In the combustion system presented the process of preparing liquid hydrocarbon fuel for combustion is one of the main factors influencing the efficiency of the conversion of chemical energy contained

Marek, Wojciech, Mitianiec, Wladyslaw

Fundamental Research on Unsteady Pre-mixed Combustion in Non-Uniform Distribution of Fuel Concentration

2001-01-3487

09/24/2001

It is significant for understanding the phenomena in a stratified charge engine and an SI engine with direct injection system to carry out the fundamental research. The experiments were conducted in a constant volume chamber with atmospheric condition. The pre-mixed charge composed of ethylene and air was charged with various equivalence ratio, the second charge with the same composition was injected into the chamber, thereafter, the combustion started by a spark plug. The phenomena were analyzed by use of the experimental results of shadowgraph, [OH] natural emission, pressure history and NOx and UHC in the exhaust gas

Fujimoto, Hajime, Senda, Jiro, Sano, M., Azechi, N., Okumi, M.

The Influence of Dilution Composition and Temperature Upon a Stratified Charge Spark Ignition Engine

2000-01-194706/19/2000

A thermodynamic model has been utilised in the analysis of a SI engine operating with a divided charge stratification system. Such a charge stratification system divides the cylinder charge into two distinct regions: a combustible charge around the spark plug and a dilution charge beyond this. The model has been utilised to reveal differing effects of both dilution charge composition (EGR or air) and temperature upon the performance and emissions of such a stratified charge engine

Calnan, Peter, Zhao, Hua, Ladomattos, Nicos, Ma, Tom

Analysis of a Stratified Charging Concept for High-Performance Two-Stroke Engines

2000-01-090003/06/2000

This paper presents the results and conclusions from a conceptual design study for a stratified charging concept. The stratified charging engine has a displacement of 64 cm3 and a four-port design with reed valves at two ports to control the bypass air. During the intake stroke of the engine, bypass air is sucked into the transfer ports to purge the air-fuel mixture present in the ports from the previous stroke back into the crankcase. This fills the transfer ports near the exhaust with pure air at the beginning of the scavenging stroke. During scavenging, the bypass air is ejected in the cylinder, shielding the exhaust against the fresh mixture coming from the ports on the intake side. This allows the hydrocarbon emissions to be reduced by over 40 %. The conceptual design study is based on an analysis of the mixture short-circuiting mechanisms and CFD investigations of the scavenging flow with charge stratification

Zahn, Wolfgang, Rosskamp, Heiko, Raffenberg, Michael, Klimmek, Axel

A Turbulent Combustion Model for a Stratified Charged, Spark Ignited Internal Combustion Engine

2000-01-027503/06/2000

A turbulent combustion model is described for SI engines with large variations in mixture strength. The model is for a single gas phase fluid at high Reynolds number and treats combustion in the laminar flamelet regime, which is characterized by high Damkholer and low Karlovitz numbers. An assumed probability density function (pdf) approach is used to extract expressions for mean quantities of interest, which are parameterized on the progress variable and mixture fraction variables. A double delta function pdf is used for the reaction progress variable and a beta function pdf is used for the mixture fraction. The reaction rate term in the progress variable equation is closed using an algebraic expression, which incorporates the effects of mixture strength, pressure and temperature on laminar flame speed. The model is implemented in two versions of a Computational Fluid Dynamics (CFD) code. The first version simulates reciprocating engine flows and the second simulates combustion in

Ranasinghe, John, Cant, Stewart

Twice Electronic Fuel Injection (TEFI)--A New Idea of Lean Combustion in S.I. Engines [ 1

2000-01-108703/06/2000

A new idea for realizing lean burn combustion with the low pressure port injection technique in S.I. engines, the technique of TEFI (Twice Electronic Fuel Injection per cycle), is proposed. That is, the total amount of fuel needed for each cycle is divided into two parts and injected at different timings to adjust and optimize the air and fuel mixture strength distribution in the cylinder. As a result, the air and fuel mixture strengths both at the spark plug region and in the whole cylinder can be adjusted arbitrarily. Therefore a lot of problems present in the conventional stratified charge engines can be avoided. Through the lean combustion experiment on a 5 valves EFI S.I. engine using the swirl control valve “SCV” technique, the advantages of the TEFI are confirmed

Shuliang, Liu, Yongjian, Fan, Pucheng, Pei

Investigation of the Fuel Distribution and the In-cylinder Flow Field in a Stratified Charge Engine Using Laser Techniques and Comparison with CFD-Modelling

1999-01-354010/25/1999

This paper presents an investigation of a Volvo Direct Injection Spark Ignition (DISI) engine, where the fuel distribution and the in-cylinder flow field have been mapped by the use of laser techniques in an engine with optical access. Along with the experimental work, CFD-modelling of flow and fuel distribution has been performed. Laser Induced Fluorescence (LIF) visualisation of the fuel distribution in a DI-engine has been performed using an endoscopic detection system. Due to the complex piston crown geometry it was not possible to monitor the critical area around the sparkplug with conventional, through the piston, detection. Therefore, an endoscope inserted in the spark plug hole was used. This approach gave an unrestricted view over the desired area. In addition, the in-cylinder flow fields have been monitored by Particle Image Velocimetry (PIV) through cylinder and piston. The results from both the LIF and the PIV measurements have been compared with CFD-modelling at Volvo. The

Richter, M., Axelsson, B., Aldén, M., Josefsson, G., Carlsson, L-O., Dahlberg, M., Nisbet, J., Simonsen, H.

Can the Best Fuel Economy of Today's Engines Still Be Improved

98191208/11/1998

Direct injection into open chambers of Diesel- and S.I.- Engines is considered by the experts of automotive engineering worldwide as the best way for future economy and ecology engines [1]. Beside of the best fuel saving passenger cars driven by Diesel engines, advanced Diesel like Stratified Charge Engines as the CCSC (Controlled Combustion Stratified Charge) and the MESC (Mixture Exhaust Stratified Charge) -Engines open the way for future developments. Both engines work with the following new elements: Air assisted injection for the formation of the combustible mixture in the small cavities of prechambers, where the load control is achieved by the quantity of the injected fuel without the need of throttling the charge of the main chamber as common in today's SI engines. Pulsed Jet Combustion, where at first in small cavities of prechambers a rich mixture gets ignited. Afterwards pulsed jets of burning gases, at least two jets moving in opposite directions, impinge each other in the

Heitland, Herbert, Rinne, Gerhart, Wislocki, Krzysztof

Power train system installed on a concept car for improving the fuel economy

5-51-9-1909/01/1997

The aim of this system named energy management system (EMS) is a remarkable improvement in fuel consumption of a power train that consists of mainly a reciprocating engine. The EMS enables high thermal efficiency of power train's operation by coordinated control of the D-4 direct injection gasoline engine and a belt type continuously variable transmission (CVT). Furthermore, a motor generator (M/G) absorbs a part of braking energy for storage and uses it during acceleration. And it enables stop of the engine while the vehicle stops running and smooth engine starting to decrease wasteful fuel consumption

Ito, Yasushi, Nakao, Hatsuo, Soga, Yoshinobu, Ogiso, Satoshi

Can the No Man's Land Between Diesel- and Otto-Engines be Bridged

95196208/01/1995

In modern Diesel engines at the best point a theoretical thermal efficiency up to 50% can be reached and, with supercharging, it is possible to obtain mean effective pressures comparable to those of Otto engines. In spite of this successful development, power density, partload behavoir, pollutant emissions and noise levels are still too high to fulfill future environmental demands. With so called hybrid engine concepts, a combination of procedures of Otto- and Diesel engines, so far only a marginal improvement of today's Otto- and Diesel engines could be reached. With a completely new design of stratified charge engines, iniated by pulsed jets generated by combustion of rich mixtures in pre chambers and followed by fireball-combustion of lean mixtures in the middle of the cylinder, surrounded by a layer of inert gas close to the cylinder wall, a quantum transition can be reached with diesel-like stratified charge engines, with which it would be possible to avoid any kind of exhaust gas

Hauser, G., Heitland, H., Wislocki, K.

Combustion and Emissions in a New Concept DI Stratified Charge Engine with Two-Stage Fuel Injection

94067503/01/1994

A new concept DISC engine equipped with a two-stage injection system was developed. The engine was modified from a single cylinder DI diesel engine with large cylinder diameter (135mm). Combustion characteristics and exhaust emissions with regular gasoline were examined, and the experiments were also made with gasoline-diesel fuel blends with higher boiling temperatures and lower octane numbers. To realize stratified mixture distribution in combustion chamber flexibly, the fuel was injected in two-stages: the first stage was before the compression stroke to create a uniform premixed lean mixture and the second stage was at the end of the compression stroke to maintain stable ignition and faster combustion. In this paper, the effect of the two-stage injection on combustion and exhaust emissions were analyzed under several operating conditions. The results showed that stable and smooth combustion without knocking over a wide range of operation could be realized in the new concept DISC

Miyamoto, Noboru, Ogawa, Hideyuki, Shudo, Toshio, Takeyama, Fumiaki

An Experimental Investigation on Air-Fuel Mixture Formation Inside a Low-Pressure Direct Injection Stratified Charge Rotary Engine

93067803/01/1993

Stratified charge engines have been getting attention for the drastic improvement in thermal efficiency at low-load region. There have been researchers on the two types of engines-the high pressure direct injection stratified charge type in which fuel is supplied directly at high pressure into its combustion chamber right before ignition timings, and the low pressure direct injection stratified charge type in which fuel is injected directly into its cylinder while the cylinder pressure is comparatively low[ 1- 3]. Rotary engines have higher freedom than reciprocating engines in terms of equipping direct fuel injection devices, since their combustion chambers rotate along the rotor housing. The fuel supply units, therefore, need not be exposed to high temperature combustion gas. Realization of the low pressure direct injection stratified charge (hereafter “LDISC”) engine is, however, almost impossible without comprehensive understanding of flow fields, because the air-fuel mixing time

Hasegawa, Yasuaki, Yamaguchi, Kouichi

Mixture Formation and Combustion in a Spark Ignition Engine with Direct Fuel Injection

92052102/01/1992

This paper presents investigations on the combustion process in a single cylinder SI engine with direct injection. Different nozzle types are examined i.e. hollow cone nozzles and hole type nozzles both with different geometry of the injected spray. These nozzle types have been compared in view of their suitability of creating a homogeneous as well as a stratified mixture in the combustion chamber. To create a homogenous mixture, the fuel was injected during the intake stroke. In order to examine the homogeneity of the mixture in the case of direct injection, the engine was driven with mixture formation generated through intake port injection. The comparison of the direct injection method with the intake port injection for homogenous mixture formation has shown only small differences in engine behavior. To create a stratified mixture in the combustion chamber, the fuel was injected at the end of the compression stroke. In the case of a low swirl level, the hollow cone nozzle with a

Spiegel, L., Spicher, U.

Visual Study of Diffusion Process of Impinging Spray in Stratified Charge Engine Using Liquid-Liquid Injection Technique

91245711/01/1991

In order to clarify a diffusion process of impinging spray on a direct fuel injection in a stratified charge engine, visual observation was made on the diffusion processes of fuel after impingement, by using a liquid-liquid injection technique by means of a single shot photography. Furthermore, the performance of actual engine adopted a impinging diffusion method was examined by using a small direct injection(D.I.) diesel engine. In this technique, the liquid fuel was injected into a plastic piston cavity which was filled with water to simulate the diffusion process of fuel after impinging against a cylindrical target vertically provided at the center of the piston cavity. The impinging spray radially diffused from the target center and formed a torus, which was viewed from the bottom and the side. The results suggest that a practical application of stratified charge engine to the small D.I. diesel engine with twin valves and an inclined injection nozzle is possible by making the end

Watanabe, Takashi

The Development of a Stratified Charge Rotary Engine Apex Seal Material

91062702/01/1991

The rotary engine has evolved into an alternate power source, along with the reciprocating engine and is finding many applications including automotive, industrial, and military. Recent advances in rotary engine technology include development of stratified charge engines with multifuel capability. These engines operate at higher peak pressures than the homogeneous charge type and require higher component mechanical strength properties and improved wear resistance for the sliding surfaces. The apex seal makes line contact with the rotor housing surface and, more than any other seal in the engine, is subjected to high contact loads and sliding surface temperatures which make it susceptible to high rate of wear. Combustion chamber pressure tightness, and thus engine performance, depend to a great extent on the apex seal wear. This requires that the phenomena associated with seal wear be studied carefully before a proper seal material can be selected. The paper presents the design and use

Revankar, G. S.

AFR and Emissions Calculations for Two-Stroke Cycle Engines

90159909/01/1990

This paper demonstrates the very useful technique of calculating air-to-fuel ratio, AFR, from exhaust gas emissions for a two-stroke cycle engine. Such methods are widely used for four-stroke engines where direct air flow measurement has now become redundant. Two modified methods are presented and compared with three standard methods, showing the accuracy to be quite good for a large set of test data from a standard two-stroke engine. A procedure for estimating AFR of the in-cylinder burning region, using trapping efficiencies, is presented for stratified charge engines, such as those with direct fuel injection. Accuracy of emissions measurement is assessed by calculating the total dry exhaust emissions, a method which could easily be automated for general test cell use. Finally, exhaust gas molecular weight and wet/dry ratio calculations are considered

Douglas, Roy

Location of Peak Pressure for an Axially Stratified-Charge Engine

87008006/01/1987

Characteristics of the cylinder pressure waveform have long been considered for optimizing the operation of automotive engines. In particular, the strategy of maintaining a constant crank angle location of the peak cylinder pressure (LPP) during combustion has been predominant in the reported studies. This technique was therefore evaluated for an existing minimum fuel consumption calibration of an experimental axially stratified-charge (ASC) engine. For the ASC engine the LPP responded to spark advance and exhaust gas recirculation changes in a similar manner to that of a homogeneous-charge engine; LPP decreased with spark advance and increased with exhaust gas recirculation. However, the LPP for the predetermined minimum fuel consumption calibration of the ASC engine varied over a range of 8° to 19° after top dead center (ATDC) under steady state conditions. This is in contrast to the nearly constant 15° ATDC LPP observed by others for most homogeneous-charge engines. In light of the

Chang, Man-Feng, Stevens, James E.

HYDRAULIC DIRECTIONAL CONTROL VALVES, 3000 PSI MAXIMUM

J748_198603 (Historical)

03/01/1986

This SAE Recommended Practice has been set up by Subcommittee 4 of the Off-Road Machinery Technical Committee and is primarily for directional control valves on construction and industrial machinery equipment as referenced in SAE J1116. The purpose is to establish port area to flow relationship and match valve spool eye ends in relation to rated capacity. Port connections are optional for either the 4-bolt split flange connection or the internal straight thread "O" ring connection

CTTC C1, Hydraulic Systems

Performance and Combustion Modeling of Heterogeneous Charge Engines

85034302/01/1985

This paper reviews the phenomoneological modeling of the combustion processes for the diesel and fuel-injected stratified charge engines. Distinctions are made between phenomenological and multi-dimensional finite-difference approaches. The modeling methodologies and the basic components in these models are described. These include characterization of the fuel spray, fuel-air mixing, ignition, burning and heat transfer processes. An attempt is made in the paper to highlight the similarities and contrasts of various models and relate to their utility in addressing emission research and engine performance development objectives

Primus, Roy J., Wong, Victor W.

Application of a Mini-Dilution Tube in the Study of Fuel Effects on Stratified Charge Engine Emissions and Combustion

81119810/01/1981

A mini-dilution tube to measure particulate emissions is described and results obtained in an application are presented. The application selected is a study of fuel effects on stratified charge engine emission and combustion characteristics. The mini-dilution tube was developed to provide a capability for particulate measurements with dynamometer engines. The device has been demonstrated to yield particulate mass results agreeing to within 10 percent of those with a full scale tunnel in steady state tests with diesel powered vehicles. A PROCO engine modified by incorporation of Torch Ignition was used in the study. Fuels were a wide cut gasoline, methanol and Indolene Clear gasoline. The engine was operated at a speed of 1250 rpm with an indicated mean effective pressure of 390 kPa. Spark timing, injection timing, EGR and equivalence ratio were varied. Gaseous and particulate emissions and combustion characteristics of the wide cut gasoline and Indolene Clear were found to be nearly

Harrington, J. A., Yetter, R. A.

Predictions of Combustion, Fuel Economy, and Emission Characteristics Influenced by the Gas Exchange Process of S. I. Engines

81082106/01/1981

The conflicting problems of fuel economy and NOx emissions in a spark ignition engines are discussed in relationship to the residual gas, volumetric efficiency and pumping loss as predicted by the gas exchange analysis which was described in a previous report (SAE P. 800535) . Predictions are made of : (1) the optimum valve timing for obtaining maximum volumetric efficiency; (2) the effect of valve timing on the residual gas and intake air charge and their relationships to the power output, fuel economy, and NO emissions; (3) the influence on combustibility and emissions of the main and auxiliary combustion chambers of a stratified charge engine; (4) the effects of the auxiliary intake valve air jet on the combustion of the lean combustion engine; (5) the effect on fuel economy of decreasing the pumping loss by adjusting valve timing and by adding EGR. These applications of the gas exchange calcualtions indicate the importance of the simulation model in evaluating combustibility, fuel

Tasaka, Hidenori, Matsuoka, Shin

On the Propagation of Turbulent Jet-Flame in a Closed Vessel

81077706/01/1981

In the stratified charge engine with an auxiliary chamber, the time required for combustion in the main chamber is considered to depend upon the characteristics of the turbulent jet-flame propagating in it. This study has been conducted to explore the controllability of the time required for combustion by changing the characteristics of the turbulent jet-flame. Experiments were performed by using a constant volume combustion chamber which was divided into a primary and a secondary chamber by an orifice plate. The characteristics of the turbulent jet-flame were changed by changing fuel, mixture strength and hole size of the orifice plate. The experimental results indicate that the time τ required for combustion in the secondary chamber mainly depends upon the jet-flame velocity VF (propagation velocity of the leading front of the jet-flame) and the mixture strength Φ. It is shown that a unique relation exists between VF and (τ SL)−1, were SL is the laminar burning velocity of the

Furukawa, Junichi, Gomi, Tsutomu

Enhanced Ignition for I. C. Engines with Premixed Gases

81014602/01/1981

The development of lean charge, fast burn engines depends crucially on enhanced ignition, since one can obtain thereby proper means for increasing the rate of burn in mixtures characterized notoriously by low normal burning speeds. Enhanced ignition involves not only high energies and long duration of ignition, but also a wide dispersion of its sources, so that combustion is carried out at as many sites throughout the charge as possible. Upon this premise, various ignition systems for I.C. engines, operating with premixed charge, are reviewed. The systems are grouped within the following categories: (1) high energy spark plugs; (2) plasma jet igniters; (3) photochemical, laser, and microwave ignition concepts; (4) torch cells; (5) divided chamber stratified charge engines; (6) flame jet igniters; (7) combustion jet ignition concepts; (8) EGR ignition system. The first three derive the power from electrical energy, the rest are powered by exothermic chemical reactions at a significantly

Dale, J. D., Oppenheim, A. K.

The Volkswagen Lean Burn PC-Engine Concept

80045602/01/1980

Results from the 1600 cm3 PCI- (PreChamber Injection) Stratified Charge Engine with a divided combustion chamber and fuel injection into the prechamber were described in SAE Paper 750 869. The main objective of continued development on this engine was to meet future emission and fuel economy standards for European countries with a simpler concept than required in the US, but equally effective. This work lead to the lean burn PC- (Pre Chamber) engine, where the prechamber fuel injection system is omitted. The main part of the program was concerned with the optimization of the PC-Combustion Process, however, the effects of the engine periphery were also considered in detail. A large number of combustion chamber parameters were thoroughly investigated on a 1300 cm3 four-cylinder water-cooled inline engine. Ignition system parameters were included in the test program because they can significantly influence the combustion process. Since an engine concept had to be developed, a large part

Brandstetter, Walter

Raman Spectroscopy and Flow Visualization Study of Stratified Charge Engine Combustion

80013602/01/1980

Transient, precombustion fuel/air ratios at the spark plug electrode gap in a DISC engine have been measured using cw laser Raman spectroscopy and have been correlated with mixture ignitability measurements. From these measurements, it was found that with decreasing quantities of injected fuel there was a general trend towards decreased peak equivalence ratio, a delay in fuel arrival at the spark electrode gap, and a narrowing of the crank angle duration over which mixture ignition was possible. Lean inflammability limits determined from the ignition study suggested a dual-ignition mechanism which depended on the rate of change of equivalence ratio with crank angle. Flow visualization of the stratified charge combustion revealed substantial differences in mixture burn characteristics and combustion duration as the ignition crank angle was varied. Quenching of the burning mixture was observed and its occurrence was correlated with the Raman measurements

Johnston, Sheridan C.

Emissions and Economy Potential of Prechamber Stratified Charge Engines

79043602/01/1979

In order to meet stringent government emissions standards without penalizing the fuel economy of gasoline engine cars, a number of alternative engine concepts have been investigated. This paper describes a research investigation and parallel development activity on prechamber stratified charge engines. Single-cylinder engine investigations are first described. Alternative design and operating parameters are investigated and compared in these engines. Design and development of two multicylinder engine designs incorporating prechamber 3-valve configurations is next described. Finally, a car development and evaluation program is outlined, using both small and large cars with alternative engine configurations and after treatment devices. Results of the above prechamber stratified charge engines are compared with conventional engines in order to assess and evaluate the emission and economy potential of this type of engine. The authors conclude that this type of stratified charge engine

Dimick, David L., Genslak, Stanley L., Greib, Ronald E., Malik, Marvin J.

A New Combustion System in the Three-Valve Stratified Charge Engine

79043902/01/1979

Through continued research on the combustion system of the stratified charge engine, we have found a new combustion system (named Branched Conduit system) which is able to further reduce exhaust emissions, HC and NOx, in particular with no adverse effect on fuel consumption under the wide range of engine operating conditions. In this paper, we describe the construction of new combustion system and its characteristics including fuel consumption and exhaust emissions. In addition, the combustion process with or without the branched conduits is examined by the time-resolved measurements of gas pressure and temperature obtained in the main combustion chamber, and observed with high-speed colored photography

Yagi, Shizuo, Fujii, Isao, Nishikawa, Masayasu, Shirai, Hiroshi

Energy Economics of Alternate Fuels

79043002/01/1979

The energy crisis of the mid-1970's released a frantic search for alternative fuels. The present paper reviews the studies undertaken by the Author's Company and outlines experience with broad specification fuels, vegetable oils and alcohols. Tests were undertaken mainly with the diesel engine and its derivatives in mind. It is concluded that, in the medium term, the most effective engine/fuel combination is an injected stratified charge engine burning “wide-cut” fuel oils. Such oil could be obtained by a modification to present natural crude refining practices, or from shale and tar sand distillation, or by coal gasification and hydrogenation, or from oil bearing vegetation. Unfortunately, the energy scene is currently confused by the conflict between short term economic gain and long term conservation needs. As a result attention is being focussed on gasolene-like alternatives, notably methyl and ethyl alcohol. As a consequence it is thought that carburetted stratified charge engines

Bertodo, R.

Multi-Dimensional Heat Flow in the Surroundings of a Pre-Chamber Under Transient Conditions

79043702/01/1979

The gas side wall temperatures of the prechamber in a divided chamber diesel or stratified charge engine have an influence on the combustion process. From this results an important effect on exhaust emissions, fuel economy and engine performance. The insulation characteristic of a prechamber insert should ensure a quick warm-up after cold start on one hand but provide not too high temperatures at full load and maximum engine speed on the other. Computations were carried out to quantify the effects of various design parameters and materials on temperature, heat flow, stress and deformation and to optimize the design under numerous existing restrictions. An analysis was made of the elasto-plastic behaviour of the insert and the cylinder head, including material creep. For most of the calculations a rotary symmetric model was assumed and solved by the finite element program system MARC. The two-dimensional mesh chosen describes the actual details of the section of the cylinder head, the

Brandstetter, W., Birth, M., Stuart, P.

Precombustion Fuel/Air Distribution in a Stratified Charge Engine Using Laser Raman Spectroscopy

79043302/01/1979

The application of cw laser Raman spectroscopy to determine precombustion fuel/air distribution in a motored, direct-injected stratified charge (DISC) engine has been demonstrated. The primary objective of the study was to obtain point measurements of the mean, gas-phase fuel/air ratio across a diameter in the combustion chamber for a single set of engine operating parameters. A secondary objective was to obtain flow visualization records of the injection-mixing process for both liquid- and gas-phase fuel injection. Results of the study showed that large spatial variations in the fuel/air ratio occur in the cylinder during and after fuel injection. Near top-dead-center, fuel/air mixing was nearly complete, but the distribution across the cylinder diameter still exhibited a region of relatively low fuel concentration

Johnston, Sheridan C.

Performance of a Stratified Charge Engine

79043402/01/1979

An experimental study of a single-cylinder direct-injected stratified charge engine is described, with emphasis upon influences of configuration and injection system details upon performance and exhaust emissions

Wood, C. D.

Simulation of Thermodynamic Cycle of Three-Valve Stratified Charge Engine

78031902/01/1978

This paper describes the development of a mathematical model for the compression, combustion, expansion, exhaust and intake processes of a three-valve stratified charge engine. After calculating the mixture formation at the end of compression process, a simple combustion model was developed to compute the gas temperature, gas pressure and the rate of formation of NO and CO at each crankangle, using basic energy and reaction kinetic equations for both the auxiliary and main chambers. The evaluation of the model was carried out by comparing the computed and experimental data. A satisfactory correlation was observed between them

Asanuma, T., Babu, M. K. Gajendra, Yagi, S.

Efficiency and Emissions of a Stratified Charge Engine Optimized for Various Fuels

78023602/01/1978

Experimental work was done with a Texaco stratified-charge engine to investigate the effect of fuel type, spark timing, and fuel injection timing on efficiency and emissions. Gasoline, diesel fuel, and a mixture of the two in equal proportions were used as fuels. The mixture of gasoline and diesel fuel simulates a broad-boiling-range fuel, referred to as “broadcut fuel.” Data were taken during full-load and part-load operations; the part-load operation simulated road-load conditions for a 3,000-lb vehicle. Results show engine efficiency ranges from about 20% at light-load to over 30% at full-load. The difference in efficiency attributable to fuel type was one to two percent. Between the two fuels gasoline and diesel, greater efficiency was associated with diesel fuel at part-load while the greater efficiency at full-load was seen with gasoline. Broadcut fuels generally resulted in efficiencies similar to the efficiencies of operation with diesel fuel at part-load or with gasoline at

Evers, L.W., Fleming, R.D., Hurn, R.W.

Prime Movers for Future Lift Trucks

78075202/01/1978

An examination of future trends in lift truck developments suggests a stable product line with a requirement for increased power at a time of escalating fuel costs. Within the time scale of the present survey (up to about the year 2000) only battery/electric and derivatives of conventional reciprocating engines will provide this power. As the turn of the century is approached, a breakthrough in the development of high density, low weight battery systems is forecast, leading to a recovery of lost market share and eventual dominance. In the intervening period gasolene and diesel-derived engines will increase their market penetration, but the opportunity of reducing, or at least containing, operating costs by the introduction of a broad specification fuel oil and injected stratified charge engines will be lost

Bertodo, R., Smith, P.

Unthrottled Open-Chamber Stratified Charge Engines

78034102/01/1978

Performance and exhaust emissions of five unthrottled open-chamber stratified charge engine designs are compared on an equivalent basis, to illustrate the effects of the different strategies used to mix the fuel and air and to provide data useful for those currently engaged in stratified charge engine development

Wood, Charles D.

The Fundamental Research of Combustion in the Stratified Charge Engine With An Auxiliary Chamber

78509601/01/1978

The major features of the stratified charge engine with an auxiliary chamber are: (1) the mixture in the combustion chamber has concentration gradient due to the auxiliary chamber and (2) turbulent flame is injected into the main chamber. The objective of this research is to examine those effects upon the combustion characteristics and the burned gas composition. The characteristics of flame propagation were examined by using a series of schlieren photographs. A summary of the major conclusion of this research is given below: (1) The mixtures supplied in the main and the auxiliary chambers burn without mixing with each other. (2) The concentrations of HC and CO decrease as the closer the mixture in the auxiliary chamber approaches stoichiometry and the leaner the mixture in the main chamber. The concentration of CO decreases as the torch opening area decreases. (3) The concentration of NOx decreases as the mixture in the auxiliary chamber becomes richer, the mixture in the main chamber

Furukawa, Junichi, Mizumura, Sakae, Yoshida, Masatake, Gomi, Tsutomu

Performance and NOx Emissions Modeling of a Jet Ignition Prechamber Stratified Charge Engine

760161

02/01/1976

The development of a cycle simulation model for the jet ignition prechamber stratified charge engine is described. Given the engine geometry, load, speed, air-fuel ratios and pressures and temperatures in the two intakes, flow ratio and a suitable combustion model, the cycle simulation predicts engine indicated efficiency and NO emissions. The relative importance of the parameters required to define the combustion model are then determined, and values for ignition delay and burn angle are obtained by matching predicted and measured pressure-time curves. The variation in combustion parameters with engine operating variables is then examined. Predicted and measured NO emissions are compared, and found to be in reasonable agreement over a wide range of engine operation. The relative contribution of the prechamber NO to total exhaust NO is then examined, and in the absence of EGR, found to be the major source of NO for overall air-fuel ratios leaner than 22:1

Hires, S. D., Ekchian, A., Heywood, John B., Tabaczynski, R. J., Wall, J. C.