Refine Your Search

Topic

Author

Affiliation

Search Results

Technical Paper

Emissions Performance of Bi-fuel CNG and Bi-fuel LPG Passenger Cars Using Sequential Multi-point Injection Systems

2001-03-05
2001-01-1195
This paper describes a study into the emissions performance of a passenger car running on natural gas and liquified petroleum gas. The gasoline engine was modified to allow the introduction of the alternative fuels into the engine. The effect of fuel system hardware on emissions was investigated. Modifications were carried out to the gasoline EMS to allow control of the alternative fuel systems. A number of changes were made to the gasoline calibration to allow operation on the alternative fuels. Emissions tests were conducted on commercial grade natural gas and liquid petroleum gas. The results were compared with gasoline emission results of an equivalent vehicle.
Technical Paper

Flow-Acoustic Coupling in Quarter-Wave Resonators Using Computational Fluid Dynamics

2001-04-30
2001-01-1430
Quarter-wave resonators are commonly used as acoustic silencers in automotive air induction systems. Similar closed side branches can also be formed in the idle air bypass, exhaust gas recirculation, and positive crankcase ventilation systems of engines. The presence of a mean flow across these side branches can lead to an interaction between the mean flow and the acoustic resonances of the side branch. At discrete flow conditions, this coupling between the flow and acoustic fields may produce high amplitude acoustic pressure pulsations. For the quarter-wave resonator, this interaction can turn the silencer into a noise generator, while for systems where a valve is located at the closed end of the side branch the large pressure pulsations can cause the valve to fail. This phenomenon is not limited to automotive applications, and also occurs in natural gas pipelines, aircraft, and numerous other internal and external flows.
Technical Paper

Wavelet-Based Visualization of Impulsive and Transient Sounds in Stationary Background Noise

2001-04-30
2001-01-1475
Scalograms based on shift-invariant orthonormal wavelet transforms can be used to analyze impulsive and transient sounds in the presence of more stationary sound backgrounds, such as wind noise or drivetrain noise. The visual threshold of detection for impulsive features on the scalogram (signal energy content vs. time and frequency,) is shown to be similar to the audible threshold of detection of the human auditory system for the corresponding impulsive sounds. Two examples of impulsive sounds in a realistic automotive sound background are presented: automotive interior rattle in a vehicle passenger compartment, and spark knock recorded in an engine compartment.
Technical Paper

An Experimental Study of the Spray Characteristics of Pressure-Swirl Atomizers for DISI Combustion Systems

2001-05-07
2001-01-1974
This paper presents results from a comprehensive experimental study of high-pressure pressure-swirl gasoline injectors tested under a range of simulated operating conditions. This study encompassed photographic analysis of single spray sequences and simultaneous measurement of axial velocity, radial velocity and diameter at point locations using the phase-doppler technique. The combination of these measurement techniques permitted an insight into the fluid dynamics of the injected spray and its development with time. Five primary stages in the spray-history were identified and numerated with experimental data.
Technical Paper

Air Charge Estimation in Camless Engines

2001-03-05
2001-01-0581
An electromechanically driven valve train offers unprecedented flexibility to optimize engine operation for each speed load point individually. One of the main benefits is the increased fuel economy resulting from unthrottled operation. The absence of a restriction at the entrance of the intake manifold leads to wave propagation in the intake system and makes a direct measurement of air flow with a hot wire air meter unreliable. To deliver the right amount of fuel for a desired air-fuel ratio, we therefore need an open loop estimate of the air flow based on measureable or commanded signals or quantities. This paper investigates various expressions for air charge in camless engines based on quasi-static assumptions for heat transfer and pressure.
Technical Paper

Overall Results: Phase I Ad Hoc Diesel Fuel Test Program

2001-03-05
2001-01-0151
The future of diesel-engine-powered passenger cars and light-duty vehicles in the United States depends on their ability to meet Federal Tier 2 and California LEV2 tailpipe emission standards. The experimental purpose of this work was to examine the potential role of fuels; specifically, to determine the sensitivity of engine-out NOx and particulate matter (PM) to gross changes in fuel formulation. The fuels studied were a market-average California baseline fuel and three advanced low sulfur fuels (<2 ppm). The advanced fuels were a low-sulfur-highly-hydrocracked diesel (LSHC), a neat (100%) Fischer-Tropsch (FT100) and 15% DMM (dimethoxy methane) blended into LSHC (DMM15). The fuels were tested on modern, turbocharged, common-rail, direct-injection diesel engines at DaimlerChrysler, Ford and General Motors. The engines were tested at five speed/load conditions with injection timing set to minimize fuel consumption.
Technical Paper

Evaluation of Some Alternative Diesel Fuels for Low Emissions and Improved Fuel Economy

2001-03-05
2001-01-0149
This paper reports on Ford's participation in the PNGV ‘Ad Hoc’ Diesel Fuel Test program - Phase I. The purpose of this program was to assess the potential benefits of various fuel properties aimed at reducing engine-out emissions of NOx and particulates to meet LEV2 and Tier 2 emission standards. Four alternative fuels were evaluated using a Ford 1.2L DIATA diesel engine: 1) California Certification fuel (CARB), 2) low sulfur hydro-cracked fuel (LSHC), 3) LSHC fuel with a 15% Dimethoxy Methane blend (DMM), and 4) neat Fischer-Tropsch (FT100) fuel. Design of Experiments (DOE) and conventional techniques were used to evaluate the fuels at five speed and load conditions. Exhaust gas recirculation (EGR), injection rail pressure, and beginning of injection (BOI) timing were controlled during the tests. Steady-state engine performance, emissions, and cylinder pressure (combustion) data were recorded for each fuel.
Technical Paper

Flame Temperature Correlation of Emissions from Diesels Operated on Alternative Fuels

2001-05-07
2001-01-2014
Work by Plee, Ahmad, and coworkers in the 1980s [1, 2, 3, 4 and 5] showed that for changes in intake air state, Diesel NOx, soot, soluble organic fraction, and HC emissions could be correlated using the stoichiometric flame temperature calculated at SOC or peak pressure conditions. In the present work, similar flame temperature correlations are obtained for emissions from three test engines; a 1.2L high speed direct injection (HSDI) Diesel, a 2.4L HSDI Diesel, and a 2.34 L single cylinder direct injection (DI) Diesel engine, the first of which was tested using four alternative fuels. Use of the flame temperature correlations presented may reduce the number of engine tests required to evaluate the effects of EGR on emissions of NOx, particulate, and HC, even when alternative fuels are used.
Technical Paper

FordS Zero Emission P2000 Fuel Cell Vehicle

2000-11-01
2000-01-C046
The P2000 Fuel Cell Electric Vehicle developed by Ford Motor Company is the first full-performance, full-size passenger fuel cell vehicle in the world. This development process has resulted in a vehicle with performance that matches some of today's vehicles powered by internal combustion engines. The powertrain in Ford's P2000 FCEV lightweight aluminum vehicle consists of an Ecostar electric motor/transaxle and a fuel cell system developed with XCELLSiS-The Fuel Cell Engine Company (formerly dbb Fuel Cell Engines, Inc.). Ballard's Mark 700 series fuel cell stack is a main component in the fuel cell system. To support this new FCEV, Ford has constructed the first North American hydrogen refueling station capable of dispensing gaseous and liquid hydrogen. On-going research and development is progressing to optimize fuel cell vehicle performance and refueling techniques.
Technical Paper

Modeling of HCCI Combustion and Emissions Using Detailed Chemistry

2001-03-05
2001-01-1029
To help guide the design of homogeneous charge compression ignition (HCCI) engines, single and multi-zone models of the concept are developed by coupling the first law of thermodynamics with detailed chemistry of hydrocarbon fuel oxidation and NOx formation. These models are used in parametric studies to determine the effect of heat loss, crevice volume, temperature stratification, fuel-air equivalence ratio, engine speed, and boosting on HCCI engine operation. In the single-zone model, the cylinder is assumed to be adiabatic and its contents homogeneous. Start of combustion and bottom dead center temperatures required for ignition to occur at top dead center are reported for methane, n-heptane, isooctane, and a mixture of 87% isooctane and 13% n-heptane by volume (simulated gasoline) for a variety of operating conditions.
Technical Paper

Evaluation of Idle Combustion Stability Using Flywheel Acceleration

2003-05-05
2003-01-1673
Vehicle idle quality has become an increasing quality concern for car manufacturers because of its impact on customer satisfaction. To get better fuel economy the overall trend is to reduce idle speed at both drive and neutral idles. This typically has adverse impact on vehicle idle quality. Lowering the idle rpm generally degrades the engine combustion stability and also makes the engine driving forces more likely to align with vehicle sensitivities (Powertrain rigid body modes, body modes, etc.). To better understand the contribution to the idle quality from different factors and carry out well-planned improvement measures, a quick and easy way to assess engine combustion stability is required.
Technical Paper

Prediction of the Knock Limit and Viable Operating Range for a Homogeneous-Charge Compression-Ignition (HCCI) Engine

2003-03-03
2003-01-1092
A method is presented for predicting the viable operating range of homogeneous-charge compression-ignition (HCCI) engines. A fundamental criterion for predicting HCCI knock is described and used to predict the minimum air/fuel ratio (and hence maximum torque) available from the engine. The lean (misfire) limit is computed using a modification of the multi-zone method of Aceves et al. [1]. Numerical improvements are described which allow even very complex fuel chemistry to be rapidly modeled on a standard PC. The viable operating range for an HCCI engine burning a primary reference fuel (PRF 95) is predicted and compared with literature experimental data. The new ability to accurately predict the operating range for any given HCCI engine/fuel combination should considerably simplify the tasks of designing a robust engine and identifying suitable fuels for HCCI.
Technical Paper

Time-Resolved, Speciated Emissions from an SI Engine During Starting and Warm-Up

1996-10-01
961955
A sampling system was developed to measure the evolution of the speciated hydrocarbon emissions from a single-cylinder SI engine in a simulated starting and warm-up procedure. A sequence of exhaust samples was drawn and stored for gas chromatograph analysis. The individual sampling aperture was set at 0.13 s which corresponds to ∼ 1 cycle at 900 rpm. The positions of the apertures (in time) were controlled by a computer and were spaced appropriately to capture the warm-up process. The time resolution was of the order of 1 to 2 cycles (at 900 rpm). Results for four different fuels are reported: n-pentane/iso-octane mixture at volume ratio of 20/80 to study the effect of a light fuel component in the mixture; n-decane/iso-octane mixture at 10/90 to study the effect of a heavy fuel component in the mixture; m-xylene and iso-octane at 25/75 to study the effect of an aromatics in the mixture; and a calibration gasoline.
Technical Paper

Simulation of Hybrid Electric Vehicles with Emphasis on Fuel Economy Estimation

1998-02-23
981132
This paper describes SHEV, a computer program created to simulate hybrid electric vehicles. SHEV employs the time-stepping technique in order to evaluate energy flow in series hybrids, and makes use of a unique method in order to speed up the fuel economy estimation. This estimation method is a refinement of the “state of charge matching” method and is explained in detail. The graphic user interfaces employed in SHEV make it easy to use and give it a look similar to regular Windows‚ applications. This paper also gives some examples of the screens created by the program, depicts its main flowchart, and describes a battery model optimized for this application.
Technical Paper

Increased Power Density via Variable Compression/Displacement And Turbocharging Using The Alvar-Cycle Engine

1998-02-23
981027
This paper presents the analysis and design of a variable compression-ratio and displacement engine concept - the Alvar Cycle using a four-stroke engine-performance simulation. The Alvar-Cycle engine uses secondary pistons which reciprocate in auxiliary chambers housed in the cylinder head, at adjustable phase-angle differences from the primary pistons. The phase difference provides both the variable total engine displacement and compression ratio. Results indicate that the Alvar engine can operate at higher power density via a combination of higher intake boost and lower compression ratio to avoid knock at high loads, and capture the better thermal efficiency at higher compression ratios at part loads.
Technical Paper

Stratified-Charge Engine Fuel Economy and Emission Characteristics

1998-10-19
982704
Data from two engines with distinct stratified-charge combustion systems are presented. One uses an air-forced injection system with a bowl-in-piston combustion chamber. The other is a liquid-only, high-pressure injection system which uses fluid dynamics coupled with a shaped piston to achieve stratification. The fuel economy and emission characteristics were very similar despite significant hardware differences. The contributions of indicated thermal efficiency, mechanical friction, and pumping work to fuel economy are investigated to elucidate where the efficiency gains exist and in which categories further improvements are possible. Emissions patterns and combustion phasing characteristics of stratified-charge combustion are also discussed.
Technical Paper

Sequence VIB Engine Test for Evaluation of Fuel Efficiency of Engine Oils - Part II. Stage Selection and Time Factor Determination

1998-10-19
982624
The newly developed Sequence VIB engine dynamometer test for measuring the ability of engine oils to improve engine fuel efficiency was designed as an improvement on its predecessor, the Sequence VIA test. The Sequence VIB test features an additional, extended oil aging to correspond to aging of engine oils in certification vehicles and in customer use, and a new set of boundary/mixed and hydrodynamic lubrication stages to better represent a wider range of engines. Five fuel economy measurement stages were chosen for the Sequence VIB test from a larger set of prototype stages, based on extensive friction modeling of engines, analysis of Sequence VIA data on reference oils, and operational considerations. Time factors for these stages were derived based on a mini-mapping of engines considering engine operating conditions in the Metro/Highway Federal fuel economy test procedure (FTP M/H) and the estimated market volume of each engine-vehicle.
Technical Paper

Sequence VIB Engine Test for Evaluation of Fuel Efficiency of Engine Oils - Part I. Aging Procedure for Determination of Fuel Efficiency Retention

1998-10-19
982623
Development of the Sequence VIB dynamometer engine test procedure for evaluating the fuel efficiency benefits of engine oils has recently been completed. This test was designed as an improvement over its predecessor, the Sequence VIA test. It evaluates fuel economy using a range of boundary/mixed and hydrodynamic lubrication stages selected to better represent a wider range of engines. In addition to determining “fresh oil” fuel economy, the new test determines fuel efficiency retention after a second oil aging stage that corresponds to 6437 - 9674 km (4,000 - 6,000 miles) of pre-certification aging of engine oils in vehicles and is representative of customer use. This paper describes the selection of aging conditions and length.
Technical Paper

Engine and Aftertreatment Modeling for Gasoline Direct Injection

1998-10-19
982596
Engine and aftertreatment models have been developed in support of gasoline direct injection (GDI) engine development and aftertreatment system design. A brief overview of the engine models that were used to project emissions and fuel economy performance for the GDI engine is presented. Additionally, the construction and validation of a NOx trap aftertreatment model is described in considerable detail. The insights and increased understanding which have been gained regarding the trade-offs between engine out emission targets, aftertreatment performance, and emission constrained fuel economy benefits for direct injection gasoline engines are reviewed and discussed.
Technical Paper

The Effect of Dimethoxy Methane Additive on Diesel Vehicle Particulate Emissions

1998-10-19
982572
FTP emissions tests on a passenger vehicle equipped with a 1.8 L IDI turbo-charged diesel engine show that the mass emissions of particles decrease by (36±8)% when 16.6% dimethoxymethane (DMM) by volume is added to a diesel fuel. Particle size measurements reveal log-normal accumulation mode distributions with number weighted geometric mean diameters in the 80 - 100 nm range. The number density is comparable for both base fuel and the DMM/diesel blend; however, the distributions shift to smaller particle diameter for the blend. This shift to smaller size is consistent with the observed reduction in particulate mass. No change is observed in NOx emissions. Formaldehyde emissions increase by (50±25)%, while emissions of other hydrocarbons are unchanged to within the estimated experimental error.
X