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Technical Paper

A Braking Force Distribution Strategy in Integrated Braking System Based on Wear Control and Hitch Force Control

2018-04-03
2018-01-0827
Abstract A braking force distribution strategy in integrated braking system composed of the main braking system and the auxiliary braking system based on braking pad wear control and hitch force control under non-emergency braking condition is proposed based on the Electronically Controlled Braking System (EBS) to reduce the difference in braking pad wear between different axles and to decrease hitch force between tractors and trailers. The proposed strategy distributes the braking force based on the desired braking intensity, the degree of the braking pad wear and the limits of certain braking regulations to solve the coupling problems between braking safety, economical efficiency of braking and the comfort of drivers. Computer co-simulations of the proposed strategy are performed.
Technical Paper

Model-Based Pneumatic Braking Force Control for the Emergency Braking System of Tractor-Semitrailer

2018-04-03
2018-01-0824
Abstract As bottom layer actuator for the AEB system, the active brake system and the brake force control of tractor-semitrailer have been the hot topics recently. In this paper, a set of active pneumatic brake system was designed based on the traditional brake system of tractor-semitrailer, which can realize the active brake of the vehicle under necessary conditions. Then, a precise mathematical model of the active pneumatic brake system was built by referring the flow characteristics of the solenoid valve, and some tests were implemented to verify the accuracy and validity of the active brake system model. Based on the model, an active pneumatic brake pressure control strategy combining the feedforward and feedback controlling modes was designed. By generating the PWM control signal, it can precisely control the desired wheel cylinder brake pressure of the active brake system. Finally, the brake pressure control strategy was validated both by simulation tests and bench tests.
Technical Paper

Electro-Hydraulic Shuttle Transmission and Control for Tractors with Non-Electronic Engine

2018-04-03
2018-01-0390
Abstract Recently, emerging technological developments in powertrain were mostly accompanied with electronics for efficient and precise control of various powertrain systems like engine, transmission, hydraulics, etc. Agricultural tractors are of no exception to this context. Most of the higher horsepower tractors above 50 HP are equipped with modern transmission systems such as Power-shuttle, Power-shift etc. having their wet clutch transmission and diesel engine controlled by an Electronic Control Unit. This is possible only with an engine that receives and provides electronic signals. Whereas a tractor with mechanical (non-electronic) engine is of predominant use in the Indian farm lands due to their low cost and immediate availability compared to that of an engine equipped with high-end electronics. Hence, there is a demand for low cost drivetrain with improved controls and without engine electronics.
Technical Paper

Conceptual Design Challenges and Solutions in Power Shuttle Transmission Development for Legacy Tractors

2018-04-03
2018-01-0394
Abstract Current developments in tractor transmission design has galloped to new heights with the introduction of CVT, Power shift, Power shuttle, hydrostatic etc besides the vastly available synchromesh and constant-mesh gearboxes. In contrary to the above existing facts of new powertrain development, there is a definite market need to revamp the heritage tractor models to be equipped with the modern transmission systems. This will help customers to have the advanced drivetrain features in the legacy tractors that have won many hearts. One such modernization was the development of new power shuttle transmission in legacy tractor models for TAFE tractors. Power shuttle primarily enables a tractor - in this case, to go forward and reverse by operating a wet clutch. A flick of lever, usually on the steering column changes the direction of the tractor at the same speed of the gear selected.
Technical Paper

Effects of Diesel Injection Parameters in a Heavy Duty Iso-Butanol/Diesel Reactivity Controlled Compression Ignition (RCCI) Engine

2018-04-03
2018-01-0197
Abstract Due to the higher combustion efficiency and fewer exhaust emissions in comparison with other diesel combustion strategies, RCCI combustion attracted lots of attention. Using two fuels with different reactivities lead to lower fuel consumption and considerably less NOx and PM emissions. An investigation has been carried out in order to examine the simultaneous effects of diesel injection pressure and single injection timing on the emissions formation and engine performance in a heavy duty single-cylinder butanol-diesel reactivity controlled compression ignition (RCCI) diesel engine. A reduced chemical n-heptane-n-butanol-PAH mechanism which consists of 76 species and 349 reactions has been used to simulate the combustion process of the dual-fuel diesel engine.
Technical Paper

A Consolidated Investigation on LPG as an Alternative Fuel for Public Utility Jeepneys

2018-04-03
2018-01-0917
Abstract This paper presents the results of a two-phase Philippine study to determine the actual mileage (km/liter) of in-use diesel and LPG (liquefied petroleum gas or Auto-LPG) public utility jeepneys plying two separate Metro Manila urban routes using both on-road and chassis dynamometer tests. Measured average load factor in on-road tests was 60-70%. Dynamometer tests at 100% load factor utilized drive cycles derived from on-road speed data. A “diesel equivalent mileage” of actual LPG mileage, deemed indicative of LPG “fuel energy conversion efficiency” relative to diesel, was calculated (based solely on fuel heating values and densities) for comparing actual mileage from both fuels. The LPG actual mileage in both on-road and laboratory tests was lower than diesel mileage. In on-road tests, the LPG actual mileage was lower than diesel actual mileage by about the same percentage LPG heating value was lower than diesel’s per liter of fuel.
Technical Paper

Gasoline Compression Ignition Operation of a Heavy-Duty Engine at High Load

2018-04-03
2018-01-0898
Abstract Engine experiments were carried out on a heavy-duty single-cylinder engine to investigate the effects of Gasoline Compression Ignition on emissions and performance of a heavy-duty engine operating at a high load condition. Comparisons between gasoline fueled operation and diesel fueled operation are presented using a single, near top dead center injection. Although the fuel’s cetane numbers are very different, the combustion characteristics of the two fuels at high load are similar, with the gasoline-fueled case showing less than two crank angle degree longer ignition delay. Gasoline operation showed lower soot production at similar levels of NOx, initiating study of the impact of exhaust gas recirculation which spanned a range of NOx levels covering the range from minimal urea dosing to high urea dosing. A conventional soot-NOx tradeoff was found to exist with gasoline as exists with diesel.
Technical Paper

Challenges for Spark Ignition Engines in Heavy Duty Application: a Review

2018-04-03
2018-01-0907
Abstract Spark Ignition (SI) engines operating on stoichiometric mixtures can employ a simple three-way catalyst as after-treatment to achieve low tailpipe emissions unlike diesel engines. This makes heavy duty (HD) SI engines an attractive proposition for low capital cost and potentially low noise engines, if the power density and efficiency requirement could be met. Specific torque at low speeds is limited in SI engines due to knock. In HD engines, the higher flame travel distances associated with higher bore diameters exacerbates knock due to increased residence time of the end gas. This report reviews the challenges in developing HD SI engines to meet current diesel power density. It also focuses on methods to mitigate them in order to achieve high thermal efficiency while running on stoichiometric condition. High octane renewable fuels are seen as a key enabler to achieve the performance level required in such applications.
Technical Paper

Investigation of Particle Number Emission Characteristics in a Heavy-Duty Compression Ignition Engine Fueled with Hydrotreated Vegetable Oil (HVO)

2018-04-03
2018-01-0909
Abstract Diesel engines are one of the most important power generating units these days. Increasing greenhouse gas emissions level and the need for energy security has prompted increasing research into alternative fuels for diesel engines. Biodiesel is the most popular amongst the alternatives for diesel fuel as it is biodegradable, renewable and can be produced domestically from vegetable oils. In recent years, hydro-treated vegetable oil (HVO) has also gained popularity due to some of its advantages over biodiesel such as higher cetane number, lower deposit formation, storage stability etc. HVO is a renewable, paraffinic biobased alternative fuel for diesel engines similar to biodiesel. Unlike biodiesel, the production process for HVO involves hydrogen as catalyst instead of methanol which removes oxygen content from vegetable oil.
Technical Paper

Optimization Design of Rear-Engine Bus Cooling System Based on 1D/3D Coupling Simulation

2018-04-03
2018-01-0771
Abstract This study investigated the effects of underhood structure parameters (two types of air ducts, two types of inlet grilles and the opening angle of inlet grilles) on the cooling characteristics of the rear-engine bus; then, the optimum design scheme of the underhood was determined. The air-side resistance load of the cooling system, which is based on fan performance, was selected as the optimization objective. Simulations were created based on a porous media model and standard a k-ε model. The next step was to build a 1D/3D coupling simulation to utilize the advantages of 1D simulation’s fast convergence speed and 3D simulation’s extensive research range. Besides, the use of 1D/3D coupling simulation can efficiently avoid the errors of simulation results which arise from the non-uniform airflow on the cooling module. Results show that the airflow rate of the rectangular air duct increased by 7 to 11percent.
Technical Paper

Dual-Fuel Gasoline-Alcohol Engines for Heavy Duty Trucks: Lower Emissions, Flexible-Fuel Alternative to Diesel Engines

2018-04-03
2018-01-0888
Abstract Long-haul and other heavy-duty trucks, presently almost entirely powered by diesel fuel, face challenges meeting worldwide needs for greatly reducing nitrogen oxide (NOx) emissions. Dual-fuel gasoline-alcohol engines could potentially provide a means to cost-effectively meet this need at large scale in the relatively near term. They could also provide reductions in greenhouse gas emissions. These spark ignition (SI) flexible fuel engines can provide operation over a wide fuel range from mainly gasoline use to 100% alcohol use. The alcohol can be ethanol or methanol. Use of stoichiometric operation and a three-way catalytic converter can reduce NOx by around 90% relative to emissions from diesel engines with state of the art exhaust treatment.
Technical Paper

Heavy Duty Diesel Engine Modeling with Layered Artificial Neural Network Structures

2018-04-03
2018-01-0870
Abstract In order to meet emissions and power requirements, modern engine design has evolved in complexity and control. The cost and time restraints of calibration and testing of various control strategies have made virtual testing environments increasingly popular. Using Hardware-in-the-Loop (HiL), Volvo Penta has built a virtual test rig named VIRTEC for efficient engine testing, using a model simulating a fully instrumented engine. This paper presents an innovative Artificial Neural Network (ANN) based model for engine simulations in HiL environment. The engine model, herein called Artificial Neural Network Engine (ANN-E), was built for D8-600 hp Volvo Penta engine, and directly implemented in the VIRTEC system. ANN-E uses a combination of feedforward and recursive ANNs, processing 7 actuator signals from the engine management system (EMS) to provide 30 output signals.
Technical Paper

Turbocharger Impact on Diesel Electric Powertrain Performance

2018-04-03
2018-01-0965
Abstract When electrifying the powertrain, there arises an opportunity to revise the traditional turbocharging trade-off between fuel-economy and transient performance. With the help of electrification, it might be possible to make the trade-off in favor of fuel economy, since transient response can be improved by the electric machine. The paper investigates this trade-off by looking at three turbocharger selections. A conventionally dimensioned turbocharger, an efficiency optimized turbocharger with maintained flow capacity, and an efficiency optimized turbocharger with increased flow capacity. The concepts are evaluated on the following cases: stationary operation, engine tip-in performance, vehicle acceleration performance, and on road fuel economy performance. The investigation is based on a validated mean value engine model of a six cylinder inline CI engine, and on a validated driveline and vehicle model of a heavy-duty truck.
Technical Paper

Pressure Amplitude Influence on Pulsating Exhaust Flow Energy Utilization

2018-04-03
2018-01-0972
Abstract A turbocharged Diesel engine for heavy-duty on-road vehicle applications employs a compact exhaust manifold to satisfy transient torque and packaging requirements. The small exhaust manifold volume increases the unsteadiness of the flow to the turbine. The turbine therefore operates over a wider flow range, which is not optimal as radial turbines have narrow peak efficiency zone. This lower efficiency is compensated to some extent by the higher energy content of the unsteady exhaust flow compared to steady flow conditions. This paper experimentally investigates the relationship between exhaust energy utilization and available energy at the turbine inlet at different degrees of unsteady flow. A special exhaust manifold has been constructed which enables the internal volume of the manifold to be increased. The larger volume reduces the exhaust pulse amplitude and brings the operating condition for the turbine closer to steady-flow.
Technical Paper

Lateral Dynamics and Suspension Tuning for a Two-Axle Bus Fitted with Roll-Resistant Hydraulically Interconnected Suspension

2018-04-03
2018-01-0831
Abstract In this paper, a new roll-plane hydraulically interconnected suspension (HIS) system is proposed to enhance the roll and lateral dynamics of a two-axle bus. It is well-known that the suspension tuning is of great importance in the design process and has also been explored in a number of studies, while only minimal efforts have been made for suspension tuning for the newly proposed HIS system especially considering lateral stability. This study aims to explore lateral dynamics and suspension tuning of a two-axle bus with HIS system, which could also provide valuable information for roll dynamics analysis. Based on a ten-DOFs lumped-mass full-car model of a bus either integrating transient mechanical-hydraulic model for HIS or the traditional suspension components, three newly promoted parameters of HIS system are defined and analyzed-namely the total roll stiffness (TRS), roll stiffness distribution ratio (RSDR) and roll-plane damping (RPD).
Technical Paper

Durability Studies on Gas Engine Oil along with Performance and Emission Characteristics of Heavy Duty Turbocharged Natural Gas Powered Engine

2018-04-03
2018-01-0638
Abstract Natural gas has been considered and implemented as alternative fuel to gasoline and diesel powered vehicles worldwide. Although natural gas belongs to petroleum fuel family, it has considerable recourses worldwide to ensure long energy security and comparatively lower carbon to hydrogen ratio that make it more environment friendly. This paper presents the effect of long duration endurance test on gas engine oil along with performance and emission characteristics of 5.8 L turbocharged heavy duty natural gas engine. The six cylinder engine was chosen due to its importance for urban bus transportation. The engine was subjected to long duration endurance test of 800 hrs with closed loop monitoring and controlled conditions as per 6 mode engine load cycle. During the complete endurance test of 800 hours, performance and emission characteristics of the engine were analyzed after completion of every 100 hours as per Full Throttle Performance Test and European Transient Cycle (ETC).
Technical Paper

Evaluation of the Technical Level of Modern Agricultural Tractors Represented in the Russian Market

2018-04-03
2018-01-0657
Abstract The paper considers a new technique for assessing the technical level of agricultural tractors competing in one power range. The existing methods of evaluation of technical level, both in Russia and abroad, are associated with expert approach that is limited by the qualitative nature of conclusions, which does not allow to predict quantitative change in performance. In this regard, if there are up to 35 models in the Russian market with equal power capabilities, the problem of making a choice arises. A general indicator of technical level is the ratio of the replacement capacity of the arable unit based on a tractor model under consideration to the replacement capacity of the arable unit based on a reference tractor, which are determined by computer simulation in reference conditions.
Technical Paper

Experimental Investigation of the Aerodynamic Benefits of Truck Platooning

2018-04-03
2018-01-0732
Abstract Lawrence Livermore National Laboratory (LLNL) has conducted a series of scaled wind tunnel tests to investigate the aerodynamic benefits of heavy vehicle platooning and the availability of cooling air for trailing vehicles on two- and three-vehicle platoons. To measure the aerodynamic drag, scale models are mounted onto a LLNL designed splitter plate by means of a low-friction linear bearing and a load cell located within each model trailer. In addition to drag, pressure measurements are made with a pitot probe positioned at the center of each model radiator grill. Particle Image Velocimetry (PIV) and Infrared Thermography (IRT) measurements are used to map the three-dimensional velocity field and flow structures around the vehicles.
Technical Paper

Study on Correlation between After-Treatment Performance and Running Conditions, Exhaust Parameters of Heavy-Duty Diesel Vehicle

2018-04-03
2018-01-0338
Abstract The increasingly stringent emission regulations have mandated the use of CCRT (catalyzed continuously regeneration trap) made by upstream DOC (diesel oxidation catalyst) and downstream CDPF (catalyzed diesel particulate filter) for heavy-duty diesel vehicles, which is proved to be the only way that can efficiently control the gaseous and particulate emissions. The performance of after-treatment is greatly influenced by the running conditions of the diesel vehicle and its exhaust parameters, so this paper intended to use grey relational analysis to study the correlation between running conditions (velocity, acceleration, VSP (vehicle specific power)), exhaust parameters (exhaust flow rate, DOC inlet temperature, concentrations of CO, THC, O2 and NOX) and the performance of DOC and CCRT based on chassis dynamometer test. Results showed that the effect of DOC on CO and THC is mainly affected by exhaust flow rate, exhaust temperature and THC concentration.
Technical Paper

Evaluation of Portable Number Emission Systems for Heavy-Duty Applications under Steady State and Transient Vehicle Operation Conditions on a Chassis Dynamometer

2018-04-03
2018-01-0348
Abstract The European Commission plans to introduce a (solid) particle number (PN) emission limit for type approval and in-service conformity (ISC) by the end of 2018 (Euro VI d) using PEMS (Portable Emission Measurement System) tests on heavy duty vehicles on the road. Performance, measurement accuracy and sensitivity of several on-board particle counters for heavy duty applications have not been tested yet in parallel on a chassis dyno with Euro VI vehicle (N3-class, 12.8 l). The PN PEMS examined were CPC (Condensation Particle Counter) and DC (Diffusion Charger) based. Evaluation was conducted at different ambient temperatures from −7 °C to 35 °C while running different test cycles: WHVC (World Harmonized Vehicle Cycle), steady state engine operation, active regeneration and ISC-tests. A particle number system following the current heavy duty regulation requirement and recommendations of the Particle Measurement Program (PMP) served as reference (PMP_TP).
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