FEV North America Inc. | Date: 2015-08-18
An exhaust diagnostic system. The system includes a diesel engine having an exhaust system with a diesel particulate filter (DPF), a diesel oxidation catalyst (DOC), a selective catalytic reduction (SCR) catalyst, a first NOx sensor located upstream of the SCR catalyst and a second NOx sensor located downstream of the SCR catalyst. In addition, an engine control unit (ECU) is in electronic communication with the first NOx sensor and the second NOx sensor. An SCR coordinator can be included and be configured to execute a non-intrusive SCR deNOx efficiency test, an intrusive SCR/DOC deNOx efficiency test and an intrusive DOC non-methane hydrocarbon (NMHC) conversion efficiency test on the exhaust system. As a result of the conversion efficiency tests, a distinction can be made as to whether the SCR catalyst or DOC is failing.
Lawler B.,State University of New York at Stony Brook |
Mamalis S.,State University of New York at Stony Brook |
Joshi S.,FEV North America Inc. |
Lacey J.,University of Melbourne |
And 3 more authors.
Applied Thermal Engineering | Year: 2017
Thermal stratification of the unburned charge prior to ignition plays a significant role in governing the heat release rates in a homogeneous charge compression ignition (HCCI) engine. A deep understanding of the conditions affecting thermal stratification is necessary for actively managing HCCI burn rates and expanding its operating range. To that end, a single-cylinder gasoline-fueled HCCI engine was used to characterize the relationship between key operating conditions, such as intake temperature, residual gas fraction, air-to-fuel ratio, and swirl, and thermal stratification. The recently developed Thermal Stratification Analysis was applied to calculate the unburned temperature distribution prior to ignition from heat release. A comparison between re-induction of exhaust gas with an air-to-fuel ratio of 24:1 and air dilution with an air-to-fuel ratio of 43:1 shows that the presence of internal residuals increases the burn duration by 34% and broadens the temperature distribution by as much as 15%. The results from an intake temperature and combustion phasing sweep at an air-to-fuel ratio of 20:1 show that heat release rates increase with advancing CA50 phasing; however, the temperature distributions broaden by 48% when comparing the most advanced to most retarded cases. To add further insight by removing the effect of combustion phasing, an equivalence ratio sweep is compared to an intake temperature sweep. It is shown that a significant part of the broadening of the distributions can be attributed exclusively to the increased intake temperature which elevates the maximum TDC temperature while leaving the wall region unaffected. However, combustion phasing plays a role as well, with earlier combustion phasing being responsible for an additional broadening of the temperature distribution. The addition of swirl elongates the burn duration by broadening the temperature distribution, with this effect being slightly larger at earlier combustion phasings. However, swirl significantly increases heat transfer losses and reduces efficiencies by as much as 1.8 percentage points. Finally, a load sweep with compensation to ensure constant combustion phasing indicates that higher loads result in increased heat release rates and narrower temperature distributions by as much as 20%. © 2016 Published by Elsevier Ltd.
Jeihouni Y.,FEV North America Inc. |
Eichler K.,RWTH Aachen |
Franke M.,FEV North America Inc.
SAE Technical Papers | Year: 2016
In order to comply with demanding Greenhous Gas (GHG) standards, future automotive engines employ advanced engine technologies including waste heat recovery (WHR) systems. A waste heat recovery system converts part of engine wasted exergies to useful work which can be fed back to the engine. Utilizing this additional output power leads to lower specific fuel consumption and CO2 emission when the total output power equals the original engine output power. Engine calibration strategies for reductions in specific fuel consumption typically results in a natural increase of NOx emissions. The utilization of waste heat recovery systems provides a pathway which gives both reduction in emissions and reduction in specific fuel consumption. According to DOE (Department of Energy), US heavy-duty truck engines' technology need to be upgraded towards higher brake thermal efficiencies (BTE). DOE target is BTE>55% for Class-8 heavy-duty vehicles in the United States. On the other side, the emissions legislation is currently under review in California aiming at around 80% reduction in NOx emission to improve air quality according to California Air Resources Board (CARB). The heavy-duty vehicles are the primary emitters of NOx. Reduction of NOx emission to such stringent proposed target demands a very high NOx catalyst efficiency and more investment in exhaust aftertreatment systems. The waste heat recovery system, however, reduces the fuel consumption as well as the engine out NOx emission at the original engine output power. The reason for that is the engine produces the same power with lower fuel energy which affects the engine operating points in engine fuel maps. This paper will discuss a feasible waste heat recovery system for on-road heavy-duty diesel engine application under relevant boundary conditions. With the help of thermodynamic calculations the incremental power from waste heat recovery system as well as the fuel economy benefit will be calculated and discussed. As main topic, potentials for reduction of NOx emission and the other pollutants by using waste heat recovery system will be presented for a representative engine. Copyright © 2016 SAE International.
Medikeri M.,FEV North America Inc. |
Tasky T.,FEV North America Inc. |
Richenhagen J.,FEV GmbH
SAE International Journal of Passenger Cars - Electronic and Electrical Systems | Year: 2015
With the increasing popularity of seamless gear changing and smooth driving experience along with the need for high fuel efficiency, transmission system development has rapidly increased in complexity. So too has transmission control software while quality requirements are high and time-to-market is short. As a result, extensive testing and documentation along with quick and efficient development methods are required. FEV responds to these challenges by developing and integrating a transmission software product line with an automated verification and validation process according to the concept of Continuous Integration (CI). Hence, the following paper outlines a software architecture called “PERSIST” where complexity is reduced by a modular architecture approach. Additionally, modularity enables testability and tracking of quality defects to their root cause. To tap this potential, the software is tested, documented and built every night with a high degree of automation in order to uncover quality risks earlier in development. The effect of that approach is shown by examples from a 7-gear series transmission project. Continuous testing and monitoring leads to a steadily increasing quality level while the project plan fulfillment can be tracked on a daily base. It is shown, that the combination of modular architecture and automated verification and validation of software helps improve the overall quality and process in the increasing complexity of the transmission system. Copyright © 2015 SAE International.
Andert J.,RWTH Aachen |
Herold K.,RWTH Aachen |
Savelsberg R.,RWTH Aachen |
Pischinger M.,FEV North America Inc.
IEEE Transactions on Control Systems Technology | Year: 2016
Range extender operation in an electric vehicle should be imperceptible to the driver from a noise/vibration standpoint. Rolling torque compensation allows virtually vibration-free range extender engine operation by utilizing a balanced counter-rotating inertia that is geared to the cranktrain. The combustion process results in engine torque fluctuations that could cause gear rattle in such a system due to a combination of torque reversal and lash in the geared connection. This brief paper addresses the problem of gear rattle in a rolling torque compensation system. First, a preloaded split gear is introduced as a potential mechanical solution to eliminate the clearance in the gear contact zone. In addition, an approach for a mechatronic solution involving active shaping of the generator torque is introduced. This methodology includes measurement of the combustion engine torque via cylinder pressure indication data, calculation of allowable torque limits, and the determination of a generator torque profile to address gear rattle. A multicriteria cost function is introduced to determine the optimal torque within the established constraints. Variations of the cost function are investigated with respect to their impact on efficiency and range extender acoustics. © 1993-2012 IEEE.
Venkitachalam H.,RWTH Aachen |
Schlosser A.,FEV GmbH |
Richenhagen J.,FEV GmbH |
Kupper M.,FEV GmbH |
Tasky T.,FEV North America Inc.
SAE Technical Papers | Year: 2015
Electrification is a key enabler to reduce emissions levels and noise in commercial vehicles. With electrification, Batteries are being used in commercial hybrid vehicles like city buses and trucks for kinetic energy recovery, boosting and electric driving. A battery management system monitors and controls multiple components of a battery system like cells, relays, sensors, actuators and high voltage loads to optimize the performance of a battery system. This paper deals with the development of modular control architecture for battery management systems in commercial vehicles. The key technical challenges for software development in commercial vehicles are growing complexity, rising number of functional requirements, safety, variant diversity, software quality requirements and reduced development costs. Software architecture is critical to handle some of these challenges early in the development process. The commercial vehicle domain is characterized by low production volumes and large number of variants. The existence of multiple vehicle level requirements, control strategies, sensors and actuators contribute towards variant diversity in software development for battery management systems. The vehicle manufacturer or the supplier has to ensure that the software fulfils certain quality characteristics based on standards. Due to increased functional complexity and cost pressure, the development process has to ensure early detection of the deviations in software quality and provide an objective feedback to the developers. Variability of the battery management system was improved by systematically representing the system topology and the functional features in a product feature model. Software architecture was derived from these functional features based on architectural design guidelines. Early detection of the deviations in software quality was ensured by verification and validation of software architecture using metrics. Metrics enabled automatic evaluation of the software architecture thereby reducing development costs, improving software quality and development efficiency. © Copyright 2015 SAE International.
Dahodwala M.,FEV North America Inc. |
Joshi S.,FEV North America Inc. |
Koehler E.,FEV North America Inc. |
Franke M.,FEV North America Inc. |
Tomazic D.,FEV North America Inc.
SAE Technical Papers | Year: 2015
Substitution of diesel fuel with natural gas in heavy-duty diesel engines offers significant advantages in terms of operating cost, as well as NOx, PM emissions and greenhouse gas emissions. However, the challenges of high THC and CO emissions, combustion stability, exhaust temperatures and pressure rise rates limit the substitution levels across the engine operating map and necessitate an optimized combustion strategy. Reactivity controlled compression ignition (RCCI) combustion has shown promise in regard to improving combustion efficiency at low and medium loads and simultaneously reducing NOx emissions at higher loads. RCCI combustion exploits the difference in reactivity between two fuels by introducing a less reactive fuel, such as natural gas, along with air during the intake stroke and igniting the air-CNG mixture by injecting a higher reactivity fuel, such as diesel, later in the compression stroke. Recent studies to optimize dual fuel diesel-CNG RCCI combustion have primarily focused on the simultaneous reduction of NOx and soot emissions. However, further investigation is needed to outline the in-cylinder conditions that are required in order for RCCI combustion to proceed. In addition, the THC emissions produced under dual fuel diesel-CNG RCCI operation need to be analyzed to better understand how to address this limitation of the technology. The current study builds on the dual fuel diesel-CNG study previously presented by the same set of authors by analyzing the experimental RCCI combustion results achieved on a heavy-duty diesel engine at 6 bar BMEP and multiple engine speeds. The study evaluates the impact of various control variables, such as CNG substitution, EGR rate and injection strategy on achieving RCCI combustion at 6 bar BMEP, thereby establishing a general framework for in-cylinder mixture properties required in realizing RCCI combustion. The conclusions at 6 bar BMEP are supported by 3D simulations of the complete combustion chamber using Converge CFD software. CFD results are also used to highlight the causes of high CH4 and CO emissions with dual fuel diesel-CNG RCCI operation. Further, the paper analyzes the experimental RCCI combustion results at 14 bar BMEP and multiple engine speeds to lay out the challenges in achieving RCCI combustion at increased engine load. Copyright © 2015 SAE International.
Parbat A.,FEV North America Inc. |
Tousignant T.,FEV North America Inc. |
Govindswamy K.,FEV North America Inc.
SAE Technical Papers | Year: 2015
The definition of vehicle and powertrain level NVH targets is one of the first tasks toward establishing where a vehicle's NVH behavior will reside with respect to the current or future state of industry. Realization of vehicle level NVH targets relies on a combination of competitive powertrain (source) and vehicle (path) NVH performance. Assessment of vehicle NVH sensitivity is well understood, and can be accomplished through determination of customer interface NVH response to measured excitations at the source input locations. However, development of appropriate powertrain source targets can be more difficult, particularly related to sound quality. This paper discusses various approaches for definition of powertrain targets for sound quality, with a specific focus on impulsive noise. Copyright © 2015 SAE International.
Tousignant T.,FEV North America Inc. |
Govindswamy K.,FEV North America Inc. |
Stickler M.,Ford Motor Company |
Lee M.-R.,Ford Motor Company
SAE Technical Papers | Year: 2015
The increasing trend toward electric and hybrid-electric vehicles (HEVs) has created unique challenges for NVH development and refinement. Traditionally, characterization of in-vehicle powertrain noise and vibration has been assessed through standard operating conditions such as fixed gear engine speed sweeps at varied loads. Given the multiple modes of operation which typically exist for HEVs, characterization and source-path analysis of these vehicles can be more complicated than conventional vehicles. In-vehicle NVH assessment of an HEV powertrain requires testing under multiple operating conditions for identification and characterization of the various issues which may be experienced by the driver. Generally, it is necessary to assess issues related to IC engine operation and electric motor operation (running simultaneously with and independent of the IC engine), under both motoring and regeneration conditions. Additionally, mode transitions, including IC engine start/stop must be assessed. An analysis is presented here, which explores the differences in NVH performance of multiple HEVs currently available in the US-market. Measurements were conducted on these vehicles to assess noise and vibration at the powertrain-level and vehicle interior. Two of the vehicles included in this investigation were then chosen for a more in-depth comparative analysis. The analysis of these two vehicles included assessment of source level excitations and vehicle NVH sensitivities, in the context of boundary conditions driven by their hybrid system architectures. Based on the powertrain and vehicle NVH performance assessments, methods were explored for developing powertrain level NVH targets. For the initial phase of this target cascading process, the analysis was limited to full load (IC engine operational) and part load (EV-only) modes. Based on in-vehicle performance, and vehicle sensitivity information, test procedures and targets were defined for powertrain radiated noise and mount vibration content. Copyright © 2015 SAE International.
FEV North America Inc. | Date: 2015-01-19
A process and a system for preventing pre-ignition in an internal combustion engine (ICE). The process includes providing an ICE that has a combustion chamber and an exhaust. Also provided is a total hydro-carbon (THC) sensor in communication with the combustion chamber. The THC sensor senses a THC level of the combusted gas for a given combustion cycle i (THC_(i)) of the ICE. In the event that THC_(i )is greater than a reference THC level (THC_(ref)), a pre-ignition countermeasure prior to an immediate subsequent combustion cycle i+1 is executed. Furthermore, the executed pre-ignition countermeasure prevents pre-ignition from occurring in the immediate subsequent combustion cycle i+1 of the ICE.