bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel Linear Hydraulic Actuator
Authors: Landberg Magnus , Hochwallner Martin , Krus Petter 
Published: January 2016

In the area of linear motion, infinite stroke only is provided by electric actuators today, until now there has been no hydraulic alternative. The novel linear hydraulic actuator consists of two double acting cylinders with a common piston rod. The working principle of this actuator for short movements is that at least one piston is connected to the piston rod and the actuator works like an ordinary hydraulic double acting cylinder.
For longer movements one of the pistons is connected alternatively to the piston rod providing the drive. In this way the two pistons are moving the piston rod alternatingly in a kind of rope climbing motion. The critical element is the clamping mechanism which is an already known machine element but used in this new application.
Advantages of this concept are as follows: The actuator is compact. Very long strokes and piston rods are allowed without side effects of common cylinders. This property is the origin of the name “infinite cylinder”. The cylinder has small chamber volumes and so high hydraulic stiffness and low capacitance. It has also potentially no external leakage.
The cylinder can provide twice the rated force for short strokes. Applications for this feature are the plate opening stroke of injection molding machines, or presses with low work to travel stroke ratio, like a press brake.
The paper includes a detailed description of the design and the working principle. One critical component is the clamping mechanism which temporarily connects the pistons to the piston rod. The clamping mechanism together with the piston represents a new kind of machine element in the mechanical engineering field. Here the focus will be on the function and the control strategy. With simulation the proposed control strategy and function will be presented and the performance analyzed. The simulation model is backed up by first results from experiments on the early prototype.
The experiments carried out so far on the hydraulic clamping mechanism, which is the critical component in the system show very promising results that the required function can be achieved. Furthermore, the function of the whole cylinder has been simulated with good result. For the full paper results from a functioning prototype is also to be expected.
On the Reduction of Combustion Noise by a Close-Coupled Pilot Injection in a Small-Bore DI Diesel Engine
Authors: Busch Stephen , Zha Kan , Warey Alok , Pesce Francesco , Peterson Richard 
Published: January 2016

For a pilot-main injection strategy in a single cylinder light duty diesel engine, the dwell between the pilot- and main-injection events can significantly impact combustion noise. As the solenoid energizing dwell decreases below 200 μs, combustion noise decreases by approximately 3 dB and then increases again at shorter dwells. A zero-dimensional thermodynamic model has been developed to capture the combustion-noise reduction mechanism; heat-release profiles are the primary simulation input and approximating them as top-hat shapes preserves the noise-reduction effect. A decomposition of the terms of the underlying thermodynamic equation reveals that the direct influence of heat-release on the temporal variation of cylinder-pressure is primarily responsible for the trend in combustion noise. Fourier analyses reveal the mechanism responsible for the reduction in combustion noise as a destructive interference in the frequency range between approximately 1 kHz and 3 kHz. This interference is dependent on the timing of increases in cylinder-pressure during pilot heat-release relative to those during main heat-release. The mechanism by which combustion noise is attenuated is fundamentally different from the traditional noise reduction that occurs with the use of long-dwell pilot injections, for which noise is reduced primarily by shortening the ignition delay of the main injection. Band-pass filtering of measured cylinder-pressure traces provides evidence of this noise-reduction mechanism in the real engine.
When this close-coupled pilot noise-reduction mechanism is active, metrics derived from cylinder-pressure such as the location of 50% heat-release, peak heat-release rates, and peak rates of pressure rise cannot be used reliably to predict trends in combustion noise. The quantity and peak value of the pilot heat-release affect the combustion noise reduction mechanism, and maximum noise reduction is achieved when the height and steepness of the pilot heat-release profile are similar to the initial rise of the main heat-release event. A variation of the initial rise-rate of the main heat-release event reveals trends in combustion noise that are the opposite of what would happen in the absence of a close-coupled pilot. The noise-reduction mechanism shown in this work may be a powerful tool to improve the tradeoffs among fuel efficiency, pollutant emissions, and combustion noise.
The Effect of In-Cylinder Turbulence on Lean, Premixed, Spark Ignited Engine Performance
Authors: Breaux Baine , Hoops Chris , Glewen William 
Published: January 2016

The intensity and structure of in-cylinder turbulence is known to have a significant effect on internal combustion engine performance. Changes in flow structure and turbulence intensity result in changes to the rate of heat release, cylinder wall heat rejection, and cycle-to-cycle combustion variability. This paper seeks to quantify these engine performance consequences and identify fundamental similarities across a range of high-speed, medium-bore, lean-burn, spark-ignited reciprocating engines. In-cylinder turbulence was manipulated by changing the extent of intake port-induced swirl as well as varying the level of piston-generated turbulence. The relationship between in-cylinder turbulence and engine knock is also discussed.
Increasing in-cylinder turbulence generally reduces combustion duration, but test results reveal that increasing swirl beyond a critical point can cause a lengthening of burn durations and greatly reduced engine performance. This critical swirl level is related to the extent of small-scale, piston generated turbulence present in the cylinder. Increasing in-cylinder turbulence generally leads to reduced cycle-to-cycle variability and increased detonation margin. The overall change in thermal efficiency was dependent on the balance of these factors and wall heat transfer, and varied depending on the operational constraints for a given engine and application. Single cylinder engine test data, supported with three dimensional CFD results are used to demonstrate and explain these basic combustion engine principles.
Comparison of Bio-Fischer-Tropsch Fuel and Commercial Diesel Fuel Application in a 1600 CC Euro 5 Diesel Engine
Authors: Nielsen Claus Suldrup , Schramm Jesper , Ivarsson Anders , Malik Azhar , Løvås Terese 
Published: January 2016

A direct injected and turbocharged Euro 5 diesel engine has been set up in a test bench where the vehicle driving conditions of the European NEDC (New European Driving Cycle) test can be simulated. The engine is operated as the engine of a corresponding vehicle, equipped with a similar engine and driving through the NEDC cycle. The regulated gaseous emissions, carbon monoxide, hydrocarbons and nitrogen oxides, as well as particulate numbers and size distributions where measured in 5 selected steady state operating points during the engine test. Fuel consumptions and carbon dioxide emissions where measured as well. The steady state operating conditions were chosen within the engine operating range during a vehicle NEDC test and representing as broad an operating range as possible during the NEDC test. A method is presented in which the NEDC test emissions are calculated from the 5 steady state measurements. It is shown that the method gives emission results that agree well with values that can be expected from the vehicle in question during an NEDC test. In this way a limited number of steady state measurements can be used to simulate vehicle emissions. The reason for carrying out engine experiments instead of vehicle measurements was to obtain well controlled engine conditions and thus better insight in the operation of the engine in the individual phases of operation, and thereby enable evaluation of the possibilities for improving engine performance with respect to emission and fuel consumption reduction.
Two different fuels where tested. These were a Fischer-Tropsch fuel, produced from biomass at the Güssing gasification plant in Austria and a commercial diesel from a fuel station in Denmark. The results of the measurements and engine modification considerations showed that bio Fischer-Tropsch fuel does have advantages with respect to particulate and also small advantages with carbon monoxide and carbon dioxide emissions. However, NOx emissions are rather a question of the injection timing of the fuel, and the NOx emissions can be adjusted to give the same level of emissions by changing the injection timing with ordinary diesel. The injection strategy was changed in order to attempt to reduce NOx emissions below the limits in the Euro 6 regulations.
High-Pressure Electronic Fuel Injection for Small-Displacement Single-Cylinder Diesel Engine
Authors: Carpenter Andrew L. , Mayo Robert E. , Wagner Jerald G. , Yelvington Paul E. 
Published: January 2016

Small-displacement, single-cylinder, diesel engines employ mechanically actuated fuel injection systems. These mechanically governed systems, while robust and low-cost, lack the ability to fully vary injection parameters, such as timing, pulse duration, and injection pressure. The ability of a particular injection system to vary these injection parameters impacts engine efficiency, power, noise, and emissions. Modern, multi-cylinder automotive engines employ some form of electronically controlled injection to take advantage of the benefits of fully variable injection, including advanced strategies such as multi-pulse injections and rate shaping. Modern diesel electronic fuel injection systems also operate at considerably higher injection pressures than mechanical fuel systems used in small-bore industrial engines. As the cost of electronic fuel systems continues to decrease and the demand for high-efficiency engines increases, electronic fuel injection becomes a more viable option for incorporation into small industrial diesel engines. In particular, this technology may be well-suited for demanding and critical applications such as military power generation.
In this study, a small-bore, single-cylinder diesel was retrofit with a custom, four-hole, high-pressure electronic fuel system. Compared to the mechanical injector, the electronic, common-rail injector had a 50% smaller orifice diameter and was designed for a 4x higher injection pressure. The mechanical governor was also replaced with an electronic speed controller. The baseline and modified engines were installed on a dynamometer, and measurements of exhaust emissions, fuel consumption, brake torque, and in-cylinder pressure were made. The electronic injector led to lower smoke opacity and NOx emissions, while CO and hydrocarbon emissions were observed to increase slightly, likely due to some wall wetting of fuel with the initial prototype injector. Testing with low ignition quality fuels was also performed, and the electronic fuel system enabled the engine to operate with fuel having a cetane number as low as 30.
Post Injection Strategy for the Reduction of the Peak Pressure Rise Rate of Neat N-Butanol Combustion
Authors: Jeftić Marko , Zheng Ming 
Published: January 2016

Enhanced premixed combustion of neat butanol in a compression ignition engine can have challenges with regards to the peak pressure rise rate and the peak in-cylinder pressure. It was proposed to utilize a butanol post injection to reduce the peak pressure rise rate and the peak in-cylinder pressure while maintaining a constant engine load. Post injection timing and duration sweeps were carried out with neat n-butanol in a compression ignition engine. The post injection timing sweep results indicated that the use of an early butanol post injection reduced the peak pressure rise rate and the peak in-cylinder pressure and it was observed that there was an optimal post injection timing range for the maximum reduction of these parameters. The results also showed that an early post injection of butanol increased the nitrogen oxide emissions and an FTIR analysis revealed that late post injections increased the emissions of unburned butanol.
The post injection duration sweep indicated that the peak pressure rise rate was significantly reduced by increasing the post injection duration at constant load conditions. There was also a reduction in the peak in-cylinder pressure. Measurements with a hydrogen mass spectrometer showed that there was an increased presence of hydrogen in the exhaust gas when the post injection duration was increased but the total yield of hydrogen was relatively low. It was observed that the coefficient of variation for the indicated mean effective pressure was significantly increased and that the indicated thermal efficiency was reduced when the post injection duration was increased. The results also showed that there were increased nitrogen oxide, carbon monoxide, and total hydrocarbon emissions for larger post injections. Although the use of a post injection resulted in emission and thermal efficiency penalties at medium load conditions, the results demonstrated that the post injection strategy successfully reduced the peak pressure rise rate and this characteristic can be potentially useful for higher load applications where the peak pressure rise rate is of greater concern.
Modifications to Improve Fuel Consumption in the Remanufacture of Spark Ignition Engines for Electric Generators
Authors: Swain Matthew Neill , Jordan Oliver Patrick , Mackey Travis Jamal , Seemann Patrick Shannon , Samarajeewa Hasitha , Swain Michael Robert 
Published: January 2016

This paper describes the development of a water cooled, lean burn, gaseous fueled engine designed for distributed power installations. Electric generators have become popular because they provide a portable supply of electrical power at consumer demand. They are used in critical need areas such as hospitals and airports, and have found their way into homes frequented with power outages or homes in remote locations. Gensets are available in a wide variety of sizes ranging from 1 kilowatt (kW) to thousands of kilowatts. In the mid-range the power sources are typically spark ignition, automotive type internal combustion engines. Since engines designed for automotive use are subject to different emission regulations, and are optimized for operation at RPMs and BMEPs above that of electric generator engines, modifications can be made to optimize them for gensets. This work describes modifications which can be made during remanufacturing an automotive engine to optimize it for use as a generator engine. While the work recognizes the potential for cost savings from the use of remanufactured automotive engines over that of using new automotive engines and the majority of the design constraints were adopted to reduce engine cost, the main focus of the work is quantifying the increase in fuel efficiency that can be achieved while meeting the required EPA emission requirements.
This paper describes the seven combustion chamber designs that were developed and tested during this work. Friction reduction was obtained in both valve train and journal bearing design. The engine optimized for fuel efficiency produced a maximum brake thermal efficiency of 37.5% with λ= 1.63. This yielded an EPA test cycle average brake specific fuel consumption (BSFC) of 325 g/kW-hr. Modification of the spark advance and low load equivalence ratio to meet EPA Phase III emission standards resulted in an EPA test cycle average BSFC of 330 gm/kW-hr. When the engine used in this research was tested in its unmodified, automotive configuration under the EPA Compliant Test Cycle it’s EPA test cycle average brake specific fuel consumption was 443.4 gm/kW-hr. This is a 34% increase in fuel consumption compared to the modified engine.
Two-Stage Turbocharging Solutions for Tier 4 Rail Applications
Authors: Bernasconi Simone , Codan Ennio , Yang David , Jacoby Pierre , Weisser German 
Published: January 2016

With the introduction of the EPA Tier 4 NOx emission limits for rail diesel engines this year, engine developers are forced to implement more advanced emission control technologies such as selective catalytic reduction (SCR) or cooled external exhaust gas recirculation (EGR). The integration and control of these systems for ensuring optimum performance throughout the operating range brings about new challenges on top of the well-known requirement for unconstrained operability in a very wide range of conditions.
As a consequence, engines and their subsystems have to be designed for maximum flexibility. The turbocharging system in particular needs to be capable of dealing with extreme ambient conditions associated with high altitudes, hot summers, severe winters, tunnel operation, etc. This flexibility must be achieved without compromising reliability and while ensuring continuous in-use compliance with the emissions standards throughout the life of the installation. At the same time, engine performance should be maintained at the highest level possible.
This study demonstrates that all of these targets can be met by combining two-stage turbocharging and EGR with suitable control elements. Two-stage turbocharging, which has become increasingly popular in other industry sectors due to its potential for improving the bsfc / NOx emissions trade-off when used in combination with correspondingly optimized valve actuation (Miller timing), is starting to be adopted also for rail applications.
A variety of EGR concepts was proposed or put into practice over the past few years, and the most important or promising of these have been taken into consideration for this study. Extensive simulations of the resulting engine and turbocharging systems have been performed using ABB’s in-house simulation platform, based on a generic engine model that can be considered representative of the rail sector.
It is shown that integration of EGR, two-stage turbocharging and appropriate control elements is highly attractive as it offers outstanding operational flexibility and very high fuel efficiency without any compromise in terms of reliability.
The selection and specification of control elements and turbocharging system components depends on the EGR concept applied. As is shown below, this can be tailored to the application to ensure optimum performance and flexibility. In view of these obvious benefits, we are very confident that such integrated EGR / two-stage turbocharging systems will be adopted more widely on railway engines.
Investigation of Cold Starting and Combustion Mode Switching as Methods to Improve Low Load RCCI Operation
Authors: Hanson Reed , Reitz Rolf 
Published: January 2016

Reactivity Controlled Compression Ignition (RCCI) is an engine combustion strategy that utilizes in-cylinder fuel blending to produce low NOx and PM emissions while maintaining high thermal efficiency. The current study investigates RCCI and conventional diesel combustion (CDC) operation in a light-duty multi-cylinder engine using a transient capable engine test cell.
The main focus of the work uses engine experiments to investigate methods which can improve low-load RCCI operation. The first set of experiments investigated RCCI operation during cold start conditions. The next set of tests investigated combustion mode switching between RCCI and CDC.
During the cold start tests, RCCI performance and emissions were measured over a range of engine coolant temperatures from 48 to 85°C. A combination of open and closed loop controls enabled RCCI to operate at a 1,500 rpm, 1 bar BMEP operating point over this range of coolant temperatures.
At a similar operating condition, i.e. 1,500 rpm, 2 bar BMEP, the engine was instantaneously switched between CDC and RCCI combustion using the same open and closed loop controls as the cold start testing. During the mode switch tests, emissions and performance were measured with high speed sampling equipment. The tests revealed that it was possible to operate RCCI down to 48°C with simple open and closed loop controls with emissions and efficiency similar to the warm steady-state values. Next, the mode switching tests were successful in switching combustion modes with minimal deviations in emissions and performance in either mode at steady-state.
In Cylinder NOx Emissions Control via Water Injection
Authors: Atkinson William , Barros Sam , Piduru Naag 
Published: January 2016

Increasingly stringent emissions standards have accounted for continuing increases in the end-user cost of a modern diesel engine, most of which due to complex and expensive emissions after treatment devices such as selective catalytic reduction (SCR), which relies on urea to be injected into a catalyst bed to remove nitrogen oxide emissions from the engine exhaust.
Prior to the current emissions standards the diesel industry had been able to meet NOx levels by reducing the combustion temperature in the engine via charge gas dilution, through cooled EGR. Although successful in reducing emissions, large levels of EGR have undesirable effects on oil quality, engine longevity, overall efficiency and warranty returns. There is also a limit to the efficacy of EGR in lowering NOx emissions such that at the current EPA mandated 0.2g/kWh, it is no longer sufficient.
Another well-known NOx mitigating solution has been the introduction of water into the diesel engine combustion chamber. This has been known to decrease peak combustion temperatures and decrease NOx emissions but usage so far has been limited to stationary and marine applications due to the requirement of a separate water tank and thereby a two-tank system. Combustion of hydrocarbon fuels produces between 1.35 and 2.55 times their mass in water. As an enabler to water injection, this paper will also demonstrate a technique where the exhaust is first cooled via a heat exchanger, and then passed through a cyclonic separator to separate heavier liquid particles from the exhaust gas flow. Through vortex separation over 100% of the burned fuel mass can be recovered as liquid water from the exhaust. A prototype system was developed and installed on a VW TDI diesel engine. Tests were conducted with and without after-treatment and results have been discussed in subsequent sections. The water was then utilized in conjunction with EGR to control NOx emissions, allowing a reduction of over 97%, thus achieving the 0.2g/kWh standard with no after treatment.