Design of an Electric Variable CAM Phaser Controller

<div class="section abstract"><div class="htmlview paragraph">Increasing concerns due to global warming have led to stringent regulation of greenhouse gas (GHG) emissions from diesel engines. Specifically, for GHG phase-2 regulation (2027), more than 4% improvement is needed when compared to phase-1 regulation (2017) in the light heavy-duty (LHD) diesel engine category. At the same time, California Air Resources Board (CARB) and Environmental Protection Agency (EPA) have proposed the new Low NOx standards that require up to 90% reduction in tailpipe (TP) NOx emissions in comparison to the current TP NOx standards that were implemented in 2010. In addition, CARB and EPA have proposed new certification requirements – Low Load Cycle (LLC) and revised heavy-duty in-use testing (HDIUT) based on the moving average window (MAW) method that would require rigorous thermal management. Hence, strategies for simultaneous reduction in GHG and TP NOx emissions are required to meet future regulations.</div><div class="htmlview paragraph">This paper presents potential pathways to achieve the GHG phase-2 and the ultra-low NOx (ULN) regulations with minimum changes in engine design, while meeting the constraints that need to be considered for engine performance stability, component durability, and vehicle drivability. Experimental evaluations were performed focusing on transient cycles such as heavy-duty Federal Test Procedure (hereafter referred as FTP), LLC, and custom transient cycles for HDIUT assessment. We used a model-year (MY) 2021 production Isuzu diesel engine and an advanced dual-dosing aftertreatment system comprising of a close-coupled SCR (ccSCR), diesel oxidation catalyst (DOC), diesel particulate filter (DPF), selective catalytic reduction (SCR), and Ammonia Slip Catalyst (ASC). Conventional thermal management techniques such as multi-injection, intake, and exhaust throttling were implemented to achieve the emissions targets. In addition to the proposed system design, this paper presents following test results from a full-scale system evaluation: <ol class="list nostyle"><li class="list-item"><span class="li-label">1</span><div class="htmlview paragraph">Achieve rapid and sustained turbine-out exhaust temperatures (>200°C) while meeting the engine-out emissions constraints for soot and total hydrocarbon (THC) emissions.</div></li><li class="list-item"><span class="li-label">2</span><div class="htmlview paragraph">A summary of TP NOx, TP N2O and GHG emissions over a composite FTP and LLC.</div></li><li class="list-item"><span class="li-label">3</span><div class="htmlview paragraph">HDIUT assessment results and observations for LLC and custom transient cycles.</div></li><li class="list-item"><span class="li-label">4</span><div class="htmlview paragraph">Robustness evaluation of TP NOx emissions for composite HDT, LLC and custom transient cycles by imposing component variations.</div></li></ol></div></div>

<div class="htmlview paragraph">Combustion in spark ignition engines is strongly affected by characteristics of in-cylinder flow. The role of in-cylinder flow on combustion becomes more important under lower temperature conditions which are made by, for example, Millor cycle engines whose power is controlled by inlet valve open and close timings (<span class="xref">1</span>)<span class="xref">*</span>.</div> <div class="htmlview paragraph">In this study, influences of early and late Inlet valve close timings have been investigated by means of an engine simulation model which is based on the entrainment model, and by means of in-cylinder flow measurements using the Hot Wire Method.</div> <div class="htmlview paragraph">Inlet valve open and close timings can be varied from 150°BBDC to 170°ABDC (in case of close timings), changing a phase between a cam shaft and a crank shaft through a gear. An early close and a late close cycles are then gotten.</div> <div class="htmlview paragraph">In case of early or late valve closed timings, decreases of magnitude of gas flow velocity and temperature have been made sure by measurements as well as by calculations.</div> <div class="htmlview paragraph">The vortex scale, however, becomes smaller under non-throttle condition. A deteriorate of thermal efficiency under early or late close timings condition, can be considerably resolved by an increase of swirl and turbulence.</div>

<div class="section abstract"><div class="htmlview paragraph">Achieving zero emissions across transportation is a tremendous challenge. The upcoming Euro 7/VII standards, set to be enforced in 2025, will mandate further reduction in ICEs exhaust emissions. Thus, additional improvements and potential new technologies and fuels are needed to design ultra-low emissions vehicles.</div><div class="htmlview paragraph">Hydrogen seems to be a very attractive fuel, thanks to its high lower heating value, clean combustion, and extremely low pollutant emissions, due to the zero-carbon content. Nevertheless, NOx emissions are still an issue in hydrogen fueled engines and optimized lean-burn combustion and suitable after-treatment NOx reduction are mandatory to reach high specific power and efficiency and near zero NOx emissions, thus enabling H2-ICE powered vehicles to be zero-impact emitting technology solution.</div><div class="htmlview paragraph">Selective Catalytic Reduction by using NH3 as the reducing agent is the most effective control technology for NOx abatement. Nevertheless, ongoing research and innovation are critical in developing new strategies for reducing NOx emissions, to overcome the NH3-SCR system main critical issues (extra equipment for urea storage and dosing, ammonia-slip, deactivation and fouling, low efficiency at low temperature).</div><div class="htmlview paragraph">The SCR of NOx by hydrogen is considered a promising alternative to traditional ammonia-based deNOx technology. The H2-SCR catalysts are suitable for engine exhaust after-treatment during cold-start and urban-driving operations, exhibiting higher catalytic activity for low-temperature NOx emissions conversion (180 – 200 °C). Furthermore, in H2-ICE powered vehicles, the additional tank to store the reducing agent is not needed with a significant simplification of the engine exhaust lay-out.</div><div class="htmlview paragraph">Experimental investigations on different H2-SCR catalysts have demonstrated that the conversion activity is greatly affected by the catalytic system configuration, the adsorption properties of the support material, the H2 spillover, that in turn are affected by H2/NO ratio and exhaust gas composition, temperature and flow rate.</div><div class="htmlview paragraph">In the present paper, a feed-forward neural network model of H2-SCR is presented, with the aim of performing real-time estimation of reduction efficiency and supporting the design of suitable H2 management to achieve maximum NOx reduction and minimum hydrogen consumption. Model training and identification are carried out against a large set of experimental data measured on a H2-SCR small scale prototype at the Synthetic Gas Bench. The experimental tests were designed to reproduce the real conditions expected at the exhaust of a H2-fueled engine.</div></div>

<div class="htmlview paragraph">In order to improve the emission and performance capabilities of modern engines several devices are introduced in the system. One of such devices is the Continuously Variable Cam Phaser (CVCP), which, by shifting the relative angle between the crank and cam shafts, allows to modify the opening and closing times of the inlet and outlet valves with respect to the base engine configuration, thus giving more design freedom. The control of the CVCP is performed by the Engine Control Unit, which both sets the desired values for the CVCP shift angle and commands the CVCP actuator to control it at the correct position.</div> <div class="htmlview paragraph">The new FIRE engine 1.4l 16v also includes a CVCP. The aim of the activity described in the paper was to perform a functional validation of the CVCP position control algorithms, through a sensitivity analysis of the CVCP control performance to a series of environmental and production variables.</div> <div class="htmlview paragraph">In order to reduce at a minimum the costs of this analysis the choice to use virtual testing as an alternative to experimental testing on the engine test bench, was taken. By this choice it was possible to analyze in simulation many more system configurations, than those available for a real experimental set-up. The building bricks for the analysis were: the definition of the test cases, operating conditions, and performance indicators for the analysis; functional simulation models of the CVCP, its actuators and sensors, developed with the device supplier, INA, of the ECU software for the control of the CVCP, and of the main environmental parameters affecting the CVCP control performance; a toolbox for the Design of Experiments, by which, once selected the design parameters subject to production, mounting or operating variability, defining the set of virtual tests to perform; some tools for the visualization and analysis of the results of the DOE.</div> <div class="htmlview paragraph">The sensitivity analysis results showed that the CVCP control system was robust to parameters variability within the tolerance ranges, being able to satisfy the prescribed performance targets.</div>

<div class="section abstract"><div class="htmlview paragraph">The customer perception of ride comfort with vehicle performance is the most important aspect in a vehicle design. The ride comfort and vehicle performance are influenced by driveline components i.e. propeller shaft phase angle, inclination angle and critical frequency of the driveline system. The optimization of the driveline system is essential to ensure the efficient and smooth power transfer. Propeller shaft is one of the critical components in the driveline to influence the vehicle performance.</div><div class="htmlview paragraph">Propeller shaft characteristics influenced by several factors like vehicle max torque, propeller shaft joint type, materials properties, UJ phase and inclination angle and shaft unbalance value. The optimization of the above parameter within the tolerance limit enables to meet the required performance standard. Various methodologies are available to optimize these parameters to enhance the vehicle performance and comfort leads to customer satisfactions. This study focuses on the analytical optimization of the propeller shaft’s universal joint (UJ) phase and inclination angle and validated at vehicle level.</div><div class="htmlview paragraph">An analytical model was employed to evaluate the velocity fluctuations across the full rotation of the propeller shaft by considering the different UJ phase angles (0<sup>°</sup> − 360<sup>°</sup>) and inclination angles (1<sup>°</sup> − 5<sup>°</sup>). It was observed from the study that optimization of these parameter improves the vibration performance and decreases the velocity fluctuations. The results shows that the well optimized propeller shaft will enhance smoothness in the driveline systems, reduction in NVH levels, vehicle performance and ride comfort. This study suggests the importance of the precise geometry alignment in driveline design and provide the further refinement methodology.</div></div>

<div class="section abstract"><div class="htmlview paragraph">The design and testing of innovative components and control logics for future vehicular platform represents a challenging task in the automotive field. The use of scale model vehicles constitutes an interesting alternative for testing assessment by decreasing time and cost efforts with a potential benefit in terms of safety.</div><div class="htmlview paragraph">The target of this research work is the development of a customized scale vehicle platform for verifying and validating innovative control strategies in safe conditions and with cost reduction. Consequently, the electrification of a radio-controlled 1:5 scale vehicle is carried out and a customized remote real-time controller is installed onboard. One of the main features of this commercial product is its modular characteristics that allows the modification of some component properties, such as the viscous coefficient of the shock absorbers, the stiffness of the springs and the suspension geometry. The original vehicle is equipped with a 2-stroke internal combustion engine, whose throttle command is provided by a common radio transceiver/receiver unit. The original configuration is commonly adopted for radio-controlled race car competitions, but the presence of a noisy combustion engine is not well suited for implementing a precise and accurate control logic based on onboard sensor measurements; hence, the conversion into an electric vehicle represents the adopted solution in this research activity.</div><div class="htmlview paragraph">In particular, the electrification process accounts for the replacement of the internal combustion engine and fuel tank with a brushless DC motor, a battery pack, and a planetary gearbox. CAD tools are exploited for the selection of the replacement components and the design of the mounting systems. Additionally, a Speedgoat Baseline Real-Time Target Machine is installed for implementing the customized control logic, developed in MATLAB/Simulink environment, for controlling the traction electric motor and the steering servomotor.</div><div class="htmlview paragraph">After a preliminary bench testing phase, a remote control is implemented for the validation of the system through maneuvers typically carried out for vehicle handling analysis.</div></div>

<div class="htmlview paragraph">The use of Diesel engines has strongly increased during the last years and now represents 30% of the sales in Europe and up to 50% of the number of cars in circulation for some countries. This success is linked not only to the economical aspect of the use of such vehicles, but also to the recent technological improvements of these engines. The new technical solutions (high pressure direct injection, turbocharging…) have indeed allowed the increase of these engine performances while decreasing their fuel consumption, pollutant emissions and noise level.</div> <div class="htmlview paragraph">From an environmental point of view, Diesel engines are nevertheless penalized by their particulate and NOx emissions. The study and the treatment of the particulate, highly criticized for their potential impact on health, are the subject of numerous works of characterization and developments.</div> <div class="htmlview paragraph">PSA Peugeot-Citroën has recently launched its particulate filter technology on several types of vehicles. In order to evaluate the durability of this technology over a long period of time, a study program has been set-up by ADEME (French environmental agency), IFP Powertrain, PSA Peugeot-Citroën and G7 (a Parisian taxi company). The objective is to study the evolution of several taxis and their after-treatment system performances over 80 000 km mileage in hard urban driving conditions, which corresponds to the recommended mileage before the first DPF maintenance.</div> <div class="htmlview paragraph">More specifically, the following evaluations are being performed at regular intervals (around 20 000 km):</div> <div class="htmlview paragraph"> <ul class="list disc"> <li class="list-item"><div class="htmlview paragraph">Regulated gaseous pollutant emissions on NEDC cycle (New European Driving Cycle)</div></li> <li class="list-item"><div class="htmlview paragraph">Particulate emissions, by mass measurement on NEDC but also by particle number and size measurement with SMPS (Scanning Mobility Particle Sizer) technique on NEDC and on unconventional steady-state running points.</div></li> <li class="list-item"><div class="htmlview paragraph">Unregulated pollutant emissions (hydrocarbons speciation C<sub>1</sub>-C<sub>13</sub>, oxygenated compounds)</div></li> </ul> </div> <div class="htmlview paragraph">The results obtained until now have not shown any degradation of the particulate filter efficiency. This paper presents the methodology setup and the explanation of the first results obtained. Indeed, a more specific study has shown that most of the aerosols measured with SMPS are composed of liquid fractions, mainly sulfates due to sulfur coming from the fuel, but also from the lubricant. The impact of sulfates stored on the catalyst surface during low temperature running phases and removed during high temperature running phases has also been outlined.</div>

<div class="section abstract"><div class="htmlview paragraph">Today turbo-diesel powertrains offering low fuel consumption and good low-end torque comprise a significant fraction of the light-duty vehicle market in Europe. Global CO₂ regulation and customer fuel prices are expected to continue providing pressure for powertrain fuel efficiency. However, regulated emissions for NO</div><div class="htmlview paragraph"> and particulate matter have the potential to further expand the incremental cost of diesel powertrain applications. Vehicle segments with the most cost sensitivity like compacts under 1400 kg weight look for alternatives to meet the CO₂ challenge but maintain an attractive customer offering. In this paper the concepts of downsizing and downspeeding gasoline engines are explored while meeting performance needs through increased BMEP to maintain good driveability and vehicle launch dynamics. A critical enabler for the solution is adoption of gasoline direct injection (GDi) fuel systems. GDi provides the ability to utilize increased scavenging without sacrificing hydrocarbon emissions because fueling and air controls can be separated. In-cylinder injection with GDi also provides charge cooling benefit yielding the knock reduction necessary for turbocharged applications. Several options within GDi are explored including multi-hole and single pintle spray generators, as well as side-mount versus central-mount applications. Both 3-cylinder and 4-cylinder base engine configurations are explored for turbocharged engines downsized to 1.2 L. Improvements in hydrocarbon emissions, heat losses and scavenging favor fewer cylinders. This is re-enforced by packaging and cost considerations. The next system aspect considered is emissions aftertreatment. Stoichiometric turbocharged GDi provides the lowest cost using the established 3-way catalyst. Stratified GDi is expected to require a lean NO</div><div class="htmlview paragraph"> trap (LNT) and diesel Euro 6 systems require addition of a diesel particulate filter (DPF) and possibly NO</div><div class="htmlview paragraph"> aftertreatment. Although the aftertreatment system to meet Euro 6 NO</div><div class="htmlview paragraph"> requirement is not known today, addition of a DPF, DPF with LNT, or DPF with urea selective catalytic reduction (SCR) represent significant cost and packaging challenges. The analysis concludes by comparing the 3-cylinder turbocharged GDi to other offerings in the context of value tradeoff of CO₂ reduction to system on-cost. Stratified 3-cylinder turbocharged GDi systems offer up to 22% CO₂ reduction compared to a baseline port-fuel-injected 4-cylinder engine. CO₂ reduction of 18% is possible for a stoichiometric GDi mechanization that employs variable valve actuation (VVA) and a conventional 3-way catalytic converter. At Euro 6 emission levels, stoichiometric 3-cylinder turbocharged GDi powertrains offer excellent value. The 3-cylinder turbo-diesel offers similar value if it is capable of meeting the NO</div><div class="htmlview paragraph"> emissions standard without lean aftertreatment. Powertrains with higher engine-out NO</div><div class="htmlview paragraph"> levels that require lean aftertreatment are significantly disadvantaged. Based on the price sensitivity of the compact car segment, the value analysis predicts the 3-cylinder turbocharged GDi engine as the powertrain of choice.</div></div>

Electric vehicles are currently being developed with the concept of saving energy and environmentally responsible. Electric vehicles use electric motors as the main driving motor. The electric motor which is currently increasingly used is the Brushless Direct Current (BLDC) motor. The BLDC motor controller is more expensive than the price of the BLDC motor itself. The BLDC motor controller has a working temperature range when working. The purpose of this study was to analyze the effect of variations in load values and the speed of electric vehicles on the temperature of the BLDC motor controller. This research was conducted by the experimental method by giving a treatment, then evaluating the effect caused on an object of research. The results showed that there was an influence of load value variations on the BLDC motor controller temperature. Values that look significant are at speeds of 0.5 m/sec and 2.5 m/sec starting from 3 kg to 5 kg. There is no influence on the variation of speed values on the temperature of the BLDC motor controller. The temperature value is stable at 2 kg and 3 kg loads with speed variations from 0.5 m/sec to 2.5 m/sec. Simultaneously variations in load and speed values affect the temperature of the BLDC motor controller by 57.7% with the lowest temperature value at 0.5 m/s and a load of 1 kg with a temperature of 33.34℃ and the highest temperature value at a speed of 2.5 m/sec and a load of 5 kg with a temperature of 37.58℃. Keywords: Electric vehicles, controllers, BLDC motors, temperature.

<div class="htmlview paragraph">As participants in GM Sunrayce 1990, students in Villanova University's College of Engineering were required to design, build, and race a solar powered electric vehicle. Since the car was required to race over an 1800 mile distance, reliability was an important design issue. Other design features of equal importance were driver safety and vehicle stability. GM also imposed additional design constraints such as minimum braking distance and maximum dimensions on solar panel and vehicle size. In this paper we will describe the tradeoffs made in designing our solar electric vehicle. This will include design considerations regarding both the mechanical and electrical subsystems separately as well as overall system integration.</div> <div class="htmlview paragraph">Our final design comprised a modified airfoil body made of a lightweight kevlar and nomex honeycomb sandwich supported on an aluminum tube space frame. The solar panel consisted of a large, flat panel integrated onto the back of the body, with additional side panels used to provide extra power during early morning and late afternoon conditions. A lightweight, brushless DC motor was used to drive a single rear wheel via interchangeable gears. This motor was capable of delivering 10 hp peak and weighed in at only 13 lbs. Silver zinc batteries were mounted on a composite tray in the center of the frame and provided power for acceleration, hill climbing, and backup power during poor insolation conditions. The wheel hubs were designed to be quick release for rapid tire changing. Low rolling resistance tires inflated to a pressure of about 90 psi were used with a composite center disk to minimize tire rolling resistance and tire aerodynamic drag. A four wheel desing was selected. The front wheels were aligned with the rear wheels to minimize drag but system, using double A-arms was chosen for all four wheels. In this lessons learned from designing and building the vehicle will be presented.</div>

<div class="htmlview paragraph">The exhaust emissions produced by the combustion of methyl ester of rapeseed oil (biofuel) have been compared with the ones obtained using a commercial diesel fuel. The tests have been carried out on a Direct Injection Turbocharged (DITC) diesel engine according respectively to the ECE 15, to a non standard STOP and GO test cycle and to the European 13 MODE test procedure. Similar engines running at the same injection timing have been adopted in performing the transient and the steady tests. PAH emissions have been measured on transient cycles.</div> <div class="htmlview paragraph">The effects of injection timing and of Exhaust Gas Recirculation (EGR) on the emission in steady state tests has been evaluated too. In particular an exhaust oxydating catalyst has been employed in presence of EGR.</div> <div class="htmlview paragraph">The tests carried out indicate that, at the same injection timing, methyl ester promotes a rise in NOx emission, a decrease in HC and CO as well as a strong reduction of smoke. Particulate matter produced by methyl ester in transient cycles is higher than that obtained with diesel fuel. Anyway a general trend to the PAH reduction has been recognized.</div> <div class="htmlview paragraph">Finally experiments have shown that NOx, HC and CO emission of biofuel may be reduced, with low effects on particulate, by the adoption of EGR in presence of an exhaust oxydating catalyst.</div>

<div class="htmlview paragraph">The specific aim is to validate an engineering model for direct injection (DI) Diesel engine emissions. Characteristic times describing the controlling fluid mechanics and chemical kinetics will be employed in the model to correlate both NOx and particulate emissions. Because the model equations are algebraic, they are suitable for implementation in a phenomenological cycle simulation program, or as an emissions model option in a computational fluid dynamics code.</div> <div class="htmlview paragraph">An original premise was that earlier work on global NO chemistry based on pollutant emissions dominated by diffusion flame contributions had adequately elucidated the kinetic aspects of the model. It is shown here that this approach is not valid for modern engines. Rather, an improved two-zone flame model for NO formation/decomposition is required. Mellor et al. [<span class="xref">1</span>] propose such a model, but include only qualitative preliminary model validation. Here we further test the model using measurements from a high speed direct injection (HSDI) Diesel engine with a common rail fuel injection system. Exhaust gas recirculation variations from zero to maximum level possible are reported and correlated for parametric variations of engine speed, injection pressure, and load.</div> <div class="htmlview paragraph">The two-zone NOx HSDI Diesel characteristic time model (CTM) involves a skeletal mechanism consisting of seven elementary reactions [<span class="xref">1</span>]. A surrogate stoichiometric flame temperature around a spray plume at start of combustion conditions represents the environment for NO-forming eddies in the first zone. The second zone surrounds the stoichiometric region, and NO decomposition may occur depending on a surrogate flame temperature at the end of combustion computed from fuel/air dual (i.e., limited-pressure) cycle analysis. Both Zeldovich and nitrous oxide mechanisms are considered in each zone.</div> <div class="htmlview paragraph">Two objectives are accomplished in the present paper. First, in Mellor et al. [<span class="xref">1</span>] the N<sub>2</sub>O mechanism was postulated to be important to the NO formation kinetics under Diesel engine in-cylinder conditions. In addition, it was suggested that NO decomposition reactions may occur at high engine loads through the reverse N<sub>2</sub>O and Zeldovich mechanisms. These hypotheses are validated using the measured engine data. Second, we extend the previous work through preliminary development of the fluid mechanic aspects of the model. A characteristic mixing time that is a function of Reynolds number, Weber number, and engine geometry is developed. When used in combination with the kinetic time for NO formation as a Damköhler number, correlations of NOx emissions for the above parametric variations are obtained for conditions where NO decomposition does not occur.</div>

<div class="htmlview paragraph">Biofuels are an important means of progress to reduce greenhouse gases and local pollution and to diversify energy. For diesel engines, FAME (Fatty Acid Methyl Ester), coming from trans esterification of vegetable oils, have already shown their potential as fuel substitutes. Nevertheless, this trans esterification induces glycerol production as a co - product. At the same time, oxygenated compounds have been shown to have great potential for reducing diesel particulate emissions. So using glycerol as a basis to synthesize new oxygenated compounds, for diesel fuel formulation could be promising.</div> <div class="htmlview paragraph">This paper deals with the synthesis of oxygenated compounds coming from glycerol, such as acetals, ethers, or carbonates, and their evaluation as blending components in diesel fuel. The objective of this work is to evaluate their potential, in terms of pollutant emissions, with different engine technologies.</div> <div class="htmlview paragraph">Their impact on particulate emissions depends on the engine technology and the chemical structure of the glycerol derivatives.</div> <div class="htmlview paragraph">For the Euro II vehicle, the decrease in particulate emissions is up to 20% on NEDC cycle.</div> <div class="htmlview paragraph">Although the Euro III vehicle is less sensitive than the Euro II, with only 5% in volume of glycerol derivatives, up to 12% of particulate reduction is possible.</div> <div class="htmlview paragraph">The impact on NOx emissions is rather low especially for the Euro III vehicle.</div> <div class="htmlview paragraph">Tests with an HCCI engine have shown that some glycerol compounds could improve the running of HCCI engine.</div>

<div class="section abstract"> <div class="htmlview paragraph">The SAE J3211 procedure applies to squeal evaluation for foundation brakes using single-ended inertia dynamometers for friction couples used on vehicles with regenerative braking systems. This document applies to squeal noise occurrences for on-road passenger cars and light trucks with a gross vehicle weight rating of 4536 kg or below and with at least one rechargeable energy storage system as a source for propulsion. The procedure incorporates aspects related to (a) minimum inertia dynamometer capabilities, (b) fixture requirements and setup, and (c) test sequences with emphasis on brake temperatures, brake pressure profiles, and strategies to represent brake blending.</div> <div class="htmlview paragraph">For this document, squeal occurs when the peak noise level is at least 70 dB(A) between 1.25 and 16 kHz for tests using full suspension corners or complete axle assemblies, or between 2 and 16 kHz for brakes not using an entire suspension corner.</div> <div class="htmlview paragraph">Test facilities intending to use this document, building on their expertise in conducting SAE J2521, shall review in detail the changes to test parameters (mainly brake temperatures and brake pressures) for legacy modules.</div> <div class="htmlview paragraph">This document also applies to vehicles with electromechanical braking systems to actuate the foundation brake. The test requester and the test facility are responsible for converting the hydraulic pressure levels into their equivalent clamping forces for brakes using electromechanical actuation.</div> <div class="htmlview paragraph">Before using this document for chassis dynamometer testing, review in detail the specifics related to at least (a) instrumentation, including in-cabin microphones; (b) threshold levels for noise detection; (c) temperature control priority between the front and rear axles; (d) vehicle loading and load distribution; (e) cooling air and environmental conditioning; (f) detailed terminology and labeling of channels and sensors; and (g) the regenerative settings and the state of charge during the test.</div> <div class="htmlview paragraph">Before using this document along with other methods to recreate the regenerative brake blending (e.g., Software-in-the-Loop or Hardware-in-the-Loop), consider (a) the vehicle powertrain, blending architecture and its applicable models, (b) actual profiles intended to recreate (e.g., control strategies, state of charge, test scenarios), and (c) actual embodiment of the simulation and integration with the native controls of the brake dynamometer.</div> <div class="htmlview paragraph">This document does not include noise from other sources (e.g., parking brakes, electric machines, driveline components).</div> </div>

<div class="section abstract"><div class="htmlview paragraph">A gasoline compression-ignition combustion system is being developed for full-time operation over the speed-load map. Low-temperature combustion was achieved using multiple late injection (MLI), intake boost, and moderate EGR for high efficiency, low NOx, and low particulate emissions. The relatively long ignition delay and high volatility of RON 91 pump gasoline combined with an advanced injection system and variable valve actuation provided controlled mixture stratification for low combustion noise.</div><div class="htmlview paragraph">Tests were conducted on a single-cylinder research engine. Design of Experiments and response surface models were used to evaluate injection strategies, injector designs, and various valve lift profiles across the speed-load operating range. At light loads, an exhaust rebreathing strategy was used to promote autoignition and maintain exhaust temperatures. At medium loads, a triple injection strategy produced the best results with high thermal efficiency. Detailed heat release analysis indicated that heat losses were significantly reduced. At higher loads, a late-intake-valve-closing strategy was used to reduce the effective compression ratio. For all tests, intake air temperature was 50 C.</div><div class="htmlview paragraph">3D CFD simulations of fuel injection, mixing, and combustion were important to understand the emissions formation processes. With multiple late injections and low-to-moderate fuel pressure, spray penetration was low, mixing was fast, and wall wetting could be avoided. Fuel sprays were characterized in a spray chamber. Injection rate was measured using a rate tube.</div><div class="htmlview paragraph">Results showed that ISFC was very low. Minimum ISFC of 181 g/kWh was measured at 2000 rpm-11 bar IMEP. For IMEP from 2 to 18 bar, engine-out NOx and PM emissions were below targets of 0.2 g/kWh and 0.1 FSN, respectively, indicating that aftertreatment for these species may be reduced or eliminated. It was found that combustion noise levels, characterized by several noise metrics, could be effectively controlled by the injection process. Measurements of exhaust particulate size distribution indicated very low particle count, especially for a preferred injector with low levels of in-cylinder swirl.</div><div class="htmlview paragraph">Collectively, these results demonstrate the potential feasibility of full-time GDCI using RON 91 gasoline at low-to-moderate injection pressures with high fuel efficiency. While more development work is needed, there is good potential for a practical GDCI powertrain system based on these concepts.</div></div>