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Technical Paper

Engine Excitation Decomposition Methods and V Engine Results

2001-04-30
2001-01-1595
Engine excitation forces have been studied in the past using one of two methods; a lumped sum or a totally distributed approach. The lumped sum approach gives the well-understood engine inherent unbalance and the totally distributed approach is used in engine CAE models to determine the overall engine response. The approach that will be described in this paper identifies an intermediate level of sophistication. The methodology implemented considers single cylinder forces on the engine block, piston side thrust and main bearing forces, and decomposes them into their order content. The forces are then phased and geometrically distributed appropriately for each cylinder and then each order is analyzed relative to know distributions that are NVH concerns, V-block breathing, block side wall breathing, and block lateral and vertical bending.
Technical Paper

Finite element simulation of drive shaft in truck/SUV frontal crash

2001-06-04
2001-06-0106
Drive shaft modelling effects frontal crash finite element simulation. A 35 mph rigid barrier impact of a body on frame SUV with an one piece drive shaft and a unibody SUV with a two piece drive shaft have been studied and simulated using finite element analyses. In the model, the drive shaft can take significant load in frontal impact crash. Assumptions regarding the drive shaft model can change the predicted engine motion in the simulation. This change influences the rocker @ B-pillar deceleration. Two modelling methods have been investigated in this study considering both joint mechanisms and material failure in dynamic impact. Model parameters for joint behavior and failure should be determined from vehicle design information and component testing. A body on frame SUV FEA model has been used to validate the drive shaft modeling technique by comparing the simulation results with crash test data.
Technical Paper

Fuel Economy Benefit of Cylinder Deactivation - Sensitivity to Vehicle Application and Operating Constraints

2001-09-24
2001-01-3591
A Variable Displacement Engine (VDE) improves fuel economy by deactivating half the cylinders at light load. The actual fuel economy benefit attained in the vehicle depends on how often cylinders can be deactivated, which is a function of test cycle, engine size, and vehicle weight. In practice, cylinder deactivation will also be constrained by NVH (noise, vibration, and harshness). This paper presents fuel economy projections for VDE in several different engine and vehicle applications. Sensitivity to NVH considerations is quantified by calculating fuel economy with and without cylinder deactivation in various operating modes: idle, low engine speed, 1st and 2nd gear, and warm-up after cold start. The effects of lug limits and calibration hysteresis are also presented.
Technical Paper

Dilution Effects on the Controlled Auto-Ignition (CAI) Combustion of Hydrocarbon and Alcohol Fuels

2001-09-24
2001-01-3606
This paper presents results from an experimental programme researching the in-cylinder conditions necessary to obtain homogenous CAI (or HCCI) combustion in a 4-stroke engine. The fuels under investigation include three blends of Unleaded Gasoline, a 95 RON Primary Reference Fuel, Methanol, and Ethanol. This work concentrates on establishing the CAI operating range with regard to Air/Fuel ratio and Exhaust Gas Re-circulation and their effect on the ignition timing, combustion rate and variability, Indicated thermal efficiency, and engine-out emissions such as NOx. Detailed maps are presented, defining how each of the measured variables changes over the entire CAI region. Results indicate that the alcohols have significantly higher tolerance to dilution than the hydrocarbon fuels tested. Also, variations in Gasoline blend have little effect on any of the combustion parameters measured.
Technical Paper

Research and Development of Controlled Auto-Ignition (CAI) Combustion in a 4-Stroke Multi-Cylinder Gasoline Engine

2001-09-24
2001-01-3608
Controlled Auto-Ignition (CAI) combustion has been achieved in a production type 4-stroke multi-cylinder gasoline engine. The engine was based on a Ford 1.7L Zetec-SE 16V engine with a compression ratio of 10.3, using substantially standard components modified only in design dimensions to control the gas exchange process in order to significantly increase the trapped residuals. The engine was also equipped with Variable Cam Timing (VCT) on both the intake and exhaust camshafts. It was found that the largely increased trapped residuals alone were sufficient to achieve CAI in this engine and with VCT, a range of loads between 0.5 and 4 bar BMEP and engine speeds between 1000 and 3500 rpm were mapped for CAI fuel consumption and exhaust emissions. The measured CAI results were compared with those of Spark Ignition (SI) combustion in the same engine but with standard camshafts at the same speeds and loads.
Technical Paper

Ford P2000 Hydrogen Engine Dynamometer Development

2002-03-04
2002-01-0242
As part of the P2000 hydrogen fueled internal combustion engine (H2ICE) vehicle program, an engine dynamometer research project was conducted in order to systematically investigate the unique hydrogen related combustion characteristics cited in the literature. These characteristics include pre-ignition, NOx emissions formation and control, volumetric efficiency of gaseous fuel injection and related power density, thermal efficiency, and combustion control. To undertake this study, several dedicated, hydrogen-fueled spark ignition engines (compression ratios: 10, 12.5, 14.5 and 15.3:1) were designed and built. Engine dynamometer development testing was conducted at the Ford Research Laboratory and the University of California at Riverside. This engine dynamometer work also provided the mapping data and control strategy needed to develop the engine in the P2000 vehicle.
Technical Paper

Ford 6.8L Hydrogen IC Engine for the E-450 Shuttle Van

2007-10-29
2007-01-4096
Ford Motor Company is researching and developing multiple propulsion strategies which include advanced gasoline engines, clean diesel, flexible fuel (ethanol blends up to E-85), hybrids and hydrogen propulsion, both in internal combustion (IC) engines and fuel cells. Hydrogen utilized as a transportation fuel is viewed as a long term solution as it is sustainable and clean when derived from renewable resources. The development and use of hydrogen IC engine (H2ICE) technology can readily be utilized to drive the transition strategy from the petroleum economy to the hydrogen economy. Because the “more conventional” H2ICE systems can be brought to market more quickly and in higher volume, business initiatives for hydrogen fueling infrastructure and other hydrogen complimentary required technologies can be realized sooner. To that end Ford has fully re-engineered a 6.8L Triton V-10 engine to run on hydrogen and power an E-450 shuttle van.
Technical Paper

Effect of Intake Primary Runner Blockages on Combustion Characteristics and Emissions with Stoichiometric and EGR-diluted Mixtures in SI Engines

2007-10-29
2007-01-3992
In-cylinder charge motion is known to significantly increase turbulence intensity, accelerate combustion rate, and reduce cyclic variation. This, in turn, extends the tolerance to exhaust gas recirculation (EGR), while the introduction of EGR results in much lowered nitrogen oxide (NOx) emissions and reduced fuel consumption. The present study investigates the effect of charge motion in a spark ignition engine on fuel consumption, combustion, and engine-out emissions with stoichiometric and EGR-diluted mixtures under part-load operating conditions. Experiments have been performed with a Chrysler 2.4L 4-valve I4 engine under 2.41 bar brake mean effective pressure at 1600 rpm over a spark range around maximum brake torque timing. The primary intake runners are partially blocked to create different levels of tumble, swirl, and cross-tumble (swumble) motion in the cylinder before ignition.
Technical Paper

Impact of Tumble on Combustion in SI Engines: Correlation between Flow and Engine Experiments

2007-10-29
2007-01-4003
The introduction of tumble into the combustion chamber is an effective method of enhancing turbulence intensity prior to ignition, thereby accelerating the burn rates, stabilizing the combustion, and extending the dilution limit. In this study, the primary intake runners are partially blocked to produce different levels of tumble motion in the cylinder during the air induction process. Experiments have been performed with a Chrysler 2.4L 4-valve I4 engine at maximum brake torque timing under two operating conditions: 2.41 bar brake mean effective pressure (BMEP) at 1600 rpm, and 0.78 bar BMEP at 1200 rpm. A method has been developed to quantify the tumble characteristics of blockages under steady flow conditions in a flow laboratory, by using the same cylinder head, intake manifold, and tumble blockages from the engine experiments.
Technical Paper

Development of a Gasoline Engine System Using HCCI Technology - The Concept and the Test Results

2002-10-21
2002-01-2832
Homogeneous-charge compression-ignition (HCCI) technology has high potential to significantly reduce fuel consumption and NOx emissions over PFI engines. Control of the HCCI combustion process over the full range of conventional PFI operating conditions, however, has been a challenge. This study describes an HCCI-SI dual-mode engine system proposal based on new approaches to optimize the engine performance. A 0.658L single-cylinder engine was built and tested using these concepts. The engine was operated in HCCI mode from idle to 5.5 bar NMEP and up to 4750 rpm. NSFC in HCCI mode was about 175 g/kWh over most of the operating range except at very low load or near the high load boundary. At a part load of 1500 rpm and an equivalent BMEP of 2.62 bar, net indicated fuel efficiency was 50% higher than PFI engines and 30% higher than a prototype SC-DISI engine.
Technical Paper

Hybrid Powertrain with an Engine-Disconnecting Clutch

2002-03-04
2002-01-0930
Several types of hybrid-electric vehicles have been developed at Ford Research Laboratory. Among the parallel hybrid systems with a single electric motor, two types were studied. In the first type, the electric motor was attached directly to the crankshaft (mild hybrid) [1], to enable the engine start-stop and regeneration functions. In the second type (full hybrid) the electric motor was connected to the engine through the use of a clutch to allow electric launch of the vehicle and pure electric driving at low speeds. The full hybrid powertrain described in this paper uses a more powerful electric motor for enhanced regenerative braking and engine power assist. An engine-disconnecting clutch saves energy during both the electric propulsion and during vehicle braking. When the clutch is disengaged the engine is shut-off, which eliminates the energy otherwise spent on motoring the engine during electric propulsion.
Technical Paper

The New 1.0l Supercharger Zetec RoCam Engine

2002-11-19
2002-01-3438
The current Brazilian tax legislation promotes vehicles, powered by engines with up to 1.0l displacement. In order to offer the customer an engine with the maximum tax advantage, a supercharged derivative of the Ford 1.0l Zetec RoCam engine was developed. The market specific boundary conditions in South America require powertrains with immediate response especially at low engine speeds. This can be achieved by a supercharged engine concept. The paper discusses the required engine modifications for the supercharger application. The combustion system was changed to benefit from the higher volumetric efficiency, including the optimisation of the intake, exhaust and bypass control system. Extensive modifications of the base engine were required to adapt the engine to the higher thermal load and the specific boundary condition of a supercharger application.
Technical Paper

Feasibility Study of an Online Gasoline Fractionating System for use in Spark-Ignition Engines

2001-03-05
2001-01-1193
A fuel fractionating system is designed and commissioned to separate standard gasoline fuel into two components by evaporation. The system is installed on a Ricardo E6 single cylinder research engine for testing purposes. Laboratory tests are carried out to determine the Research Octane Number (RON) and Motoring Octane Number (MON) of both fuel fractions. Further tests are carried out to characterize Spark-Ignition (SI) and Controlled Auto-Ignition (CAI) combustion under borderline knock conditions, and these are related to results from some primary reference fuels. SI results indicate that an increase in compression ratio of up to 1.0 may be achieved, along with better charge ignitability if this system is used with a stratified charge combustion regime. CAI results show that the two fuels exhibit similar knock-resistances over a range of operating conditions.
Technical Paper

Study of a Stratified-Charge DISI Engine with an Air-Forced Fuel Injection System

2000-06-19
2000-01-2901
A small-bore 4-stroke single-cylinder stratified-charge DISI engine using an air-forced fuel injection system has been designed and tested under various operating conditions. At light loads, fuel consumption was improved by 16∼19% during lean, stratified-charge operation at an air-fuel ratio of 37. NOx emissions, however, were tripled. Using EGR during lean, stratified-charge operation significantly reduced NOx emissions while fuel consumption was as low as the best case without EGR. It was also found that combustion and emissions near the lean limit were a strong function of the combination of injection and spark timings, which affect the mixing process. Injection pressure, air injection duration, and time delay between fuel and air injections also played a role. Generating in-cylinder air swirl motion slightly improved fuel economy.
Technical Paper

Engine Radiated Noise Prediction Modeling Using Noise Source Decomposition and Regression Analysis

2005-05-16
2005-01-2383
An engine's radiated noise level is a very important attribute required for delivering customer satisfaction. Having an accurate radiated noise prediction capability during the planning, target setting, and initial design phases is critical to making the up-front decisions that enable the timely and cost efficient delivery of an engine that meets its radiated noise goals. This paper describes a simple radiated noise model that is based on a combination of regression modeling and simplified analytical modeling. The regression model uses measured data from multiple tests that can be broken down to noise sources such as mechanical, combustion, and accessory components. The simple analytical models are used to determine the parameters that the decomposed noise data is regressed against. The model developed in the paper is then compared to previous models suggested in the literature and to measured data from engines.
Technical Paper

A Predictive Model for Feedgas Hydrocarbon Emissions: An Extension to Warm Engine Maps

2005-10-24
2005-01-3862
A feedgas hydrocarbon emissions model that extends the usefulness of fully-warmed steady-state engine maps to the cold transient regime was developed for use within a vehicle simulation program that focuses on the powertrain control system (Virtual Powertrain and Control System, VPACS). The formulation considers three main sources of hydrocarbon. The primary component originates from in-cylinder crevice effects which are correlated with engine coolant temperature. The second component includes the mass of fuel that enters the cylinder but remains unavailable for combustion (liquid phase) and subsequently vaporizes during the exhaust portion of the cycle. The third component includes any fuel that remains from a slow or incomplete burn as predicted by a crank angle resolved combustion model.
Technical Paper

The Effects of Aging Temperature and Air-Fuel Ratio on the NOx Storage Capacity of a Lean NOx Trap

2004-03-08
2004-01-1493
This paper summarizes results from a study on the effects of aging temperature and A/F ratio on the NOx storage capacity of a lean NOx trap. When aged at stoichiometry at 700°C, the NOx storage capacity of the NOx trap dropped considerably during the first 200 hours of aging and then at a much slower rate beyond 200 hours. The NOx storage capacity dropped more rapidly as the aging temperature increased, with the drop in capacity particularly evident between 900°C and 1000°C. The drop in NOx capacity was significantly larger for samples aged with part-time lean operation and/or part-time rich operation than for samples aged continuously at stoichiometry. The detrimental effects of lean and rich operation increased as the temperature increased. A Pt/Al2O3 model catalyst was exposed to reducing conditions at temperatures ranging from 670°C to 1041°C and then to oxidizing conditions over the same temperature range, and in-situ XRD was used to investigate Pt particle coarsening.
Technical Paper

Active Bolster for Side Impact Protection

2008-04-14
2008-01-0191
This paper discusses the simulation based methodology for designing and developing a deployable vehicle door interior trim, an Active Side Bolster (ASB), and its interaction (in FEA simulation) with an ATD in side impact crash test modes like FMVSS2141 Oblique Pole, IIHS2 and LINCAP. The FEA models, especially with the complexity of the full vehicle structure, the ATDs3 and the airbags, require extensive correlation using vehicle tests. A methodology is outlined here to ensure that the model results could be used to generate FEA ATD assessments without a significant numerical contamination of the results. These correlated FEA models for side impact vehicle tests and ATDs were used to simulate various side impact crash test conditions; such as IIHS barrier, the FMVSS-214 Oblique Pole and LINCAP. The ATD responses from the baseline vehicle FEA models and those modified with the addition of an ASB in the door shows improvement in assessment values due to the introduction of the ASB.
Technical Paper

A New FEA Method for the Evaluation of a Body Joint

2001-03-05
2001-01-0758
A finite element analysis method has been developed to assess the design of an automobile body joint. The concept of the coefficient of joint stiffness and the force distribution ratio are proposed accordingly. The coefficient of joint stiffness reveals whether a joint is stiff enough compared to its joining components. In addition, these parameters can be used to estimate the potential and the effectiveness for any further improvement of the joint design. The modeling and analysis of the proposed process are robust. The coefficient of joint stiffness could be further developed to serve as the joint design target.
Technical Paper

Demonstration of HCCI Using a Single Cylinder Four-stroke SI Engine with Modified Valve Timing

2000-10-16
2000-01-2870
A standard port fuel injected, unthrottled single cylinder four-stroke SI engine, with a compression ratio of 10.3:1, and using standard gasoline fuel, has been adapted to operate in the homogeneous charge compression ignition (HCCI) mode, by modifying the valve timing. It has been found that over a speed range of between 1300 and 2000 rpm, and lambda values of between 0.95 and 1.1, stable operation is achieved without spark ignition. The internal EGR rate was estimated to be about 60%, and emissions of NOX were typically 0.25 g/kWh. Practical implementation of this HCCI concept will require variable valve timing, which will also enable reversion to standard SI operation for maximum power.
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