Automotive Combustion Engines Research Articles

Research of pollutant emissions from automotive internal combustion engines in conditions corresponding to the actual use of vehicles

The subject of the article is the study of pollutant emissions from automotive combustion engines that operate in conditions corresponding to the actual use of vehicles. Includes information on the properties of exhaust gas parameters characterizing the following features: energy, economic, environmental impact and serviceability, additional and constant. Reference was also made to the possibility of determining driving tests on the basis of the similarity of the frequency characteristics of the speed processes in both driving tests and in the real use of vehicles. The article presents the results of research on pollutant emissions from a passenger car during the RDE test. The emission of carbon monoxide, hydrocarbons, nitrogen oxides, particulate matter and carbon dioxide, as well as the number of particulate matter, were examined. The process of pollutant emission intensity and particle number intensity was presented. Tests were carried out on the statistical properties of the car speed, the intensity of pollutant emissions, and the intensity of the number of particulate matter. Correlation studies were carried out on the speed of the vehicle, the intensity of pollutant emissions, and the intensity of the number of particulate matter.

Fabrication and Testing of Bioinspired Surface Designs for Friction Reduction at the Piston Ring and Liner Interface

Abstract The piston ring and liner interface is a major source of friction loss in automotive combustion engines. This loss can be mitigated by learning from surfaces from nature that manipulate friction. In this study, novel fabrication and testing methods were developed and used to efficiently compare three-dimensional bioinspired surface designs to existing piston liner surface topographies. Surface designs inspired by frog toes were fabricated using two-photon lithography, and their frictional performance is compared to that of typical piston liner topography. These designs reduce surface friction by an average of 18%, and up to 39%, compared to a flat control. The developed fabrication and testing methods allow comparison with existing topographies without needing to transfer the designs to the original materials and provide an efficient approach for designing surfaces to meet the frictional challenges of the future.

Indirect Estimator of Speed for a DC Motor Embedded in an Automotive Combustion Engine

This paper develops an estimator of speeds indirect for a DC motor embedded in an electrical water pump installed in internal combustion engines. The benefit of this technique is that the estimation framework doesn't require a dynamometer or machine-like coupling. The test results were based on the Motor Current Signal Analysis (MCSA) technique that is commonly used in an AC motor and has a great performance for measuring the rotational speed of electric motors. Two tests were used, one with DC motors using a dynamometer to validate the indirect reading of the rotation and another using the indirect estimator of speed developed in this work. This technique had positive results, regardless of the type of current sensor used. The preliminary outcomes from a research center model were introduced to justify the practicality of the proposed estimator of speed.

An Indirect Estimator of Speed for a DC Motor Embedded in an Automotive Combustion Engine

This paper develops an estimator of speeds indirect for a DC motor embedded in an electrical water pump installed in internal combustion engines. The benefit of this technique is that the estimation framework doesn't require a dynamometer or machine-like coupling. The test results were based on the Motor Current Signal Analysis (MCSA) technique that is commonly used in an AC motor and has a great performance for measuring the rotational speed of electric motors. Two tests were used, one with DC motors using a dynamometer to validate the indirect reading of the rotation and another using the indirect estimator of speed developed in this work. This technique had positive results, regardless of the type of current sensor used. The preliminary outcomes from a research center model were introduced to justify the practicality of the proposed estimator of speed.

Thermo‐chemical conversion of biomass and upgrading to biofuel: The Thermo‐Catalytic Reforming process – A review

AbstractThermo‐catalytic reforming (TCR®) is a promising conversion technology for the production of liquid bio‐fuels. The process is a proven opportunity to convert biological wastes and residues into hydrogen‐rich syngas, high‐quality oil, and char without volatiles. Bio‐oil produced from TCR® has a high carbon content, low water content, low oxygen content, and a high heating value; it is therefore directly applicable as feed in boilers or as blend in dual fuel engines. A feasible opportunity for using bio‐oil in automotive combustion engines is a further upgrade step to bio‐fuel by hydrogenation. During this hydrotreatment, heterogeneous atoms like sulfur, nitrogen, and oxygen are removed or substituted with hydrogen. Fraunhofer UMSICHT already produces gasoline and diesel that comply with European fuel standards EN 228 and EN 590, using different catalysts like NiMo/Al2O3, CoMo/Al2O3, and Ru/C for hydrogenation at 643 K and a constant hydrogen pressure of 14 MPa. Various hydrocarbons and benzene derivatives are verified after hydrotreating. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.

Design Optimization of an Automotive Turbocharger Thrust Bearing Using a CFD-Based THD Computational Approach

In a quest to reduce fuel consumption and emissions of automotive combustion engines, friction losses from many different sources need to be minimized. For modern designs of turbochargers commonly used in the automotive industry, reduction of friction losses results in better efficiency and also contributes to a faster transient response. The thrust bearing is one of the main contributors to the mechanical losses of a turbocharger. Therefore, it is crucial to optimize the design of the thrust bearing so that it has minimum friction losses while keeping sufficient thrust carrying capacity. One of the main challenges of turbocharger thrust bearing design, is that rotation speed is not fixed: the turbocharger may have a rotation speed which varies between 0 to as much as 250 kRPM. Moreover, the thrust bearing generates considerable heat, which changes the temperature of the oil film and its surroundings. In the present work, the design of the thrust bearing of an automotive turbocharger has been optimized. A CFD-based Thermohydrodynamic (THD) computational approach has been developed, taking into consideration heat dissipation, conjugate heat transfer throughout the bearing domain including the surrounding parts, as well as shear thinning and cavitation in the lubricant domain. An optimizer has been coupled to the CFD solver, with the aim of identifying bearing designs with reduced friction losses. Two bearing concepts have been evaluated: a taper-land design—which is a commonly applied thrust bearing concept—as well as a pocket bearing design. The resulting optimum pocket designs exhibit improved performance, in comparison to the optimum taper-land design. The present results indicate that (a) the pocket design concept can substantially contribute to further reducing the friction losses of a turbocharger, and (b) optimal design parameters of pocket bearings depend on the specific application (size, operating conditions), therefore detailed calculations should be performed to verify optimum performance.

Microstructural design and mechanical properties of a cast and heat-treated intermetallic multi-phase γ-TiAl based alloy

Advanced intermetallic multi-phase γ-TiAl based alloys, such as TNM alloys with a nominal composition of Ti–43.5Al–4Nb–1Mo–0.1B (in at.%), are potential candidates to replace heavy Ni-base superalloys in the next generation of aircraft and automotive combustion engines. Aimed components are turbine blades and turbocharger turbine wheels. Concerning the cost factor arising during processing, which – additionally to material costs – significantly influences the final price of the desired components, new processing solutions regarding low-cost and highly reliable production processes are needed. This fundamental study targets the replacement of hot-working, i.e. forging, for the production of turbine blades. But without forging no grain refinement takes place by means of a recrystallization process because of the lack of stored lattice defects. Therefore, new heat treatment concepts have to be considered for obtaining final microstructures with balanced mechanical properties in respect to sufficient tensile ductility at room temperature as well as high creep strength at elevated temperatures. This work deals with the adjustment of microstructures in a cast and heat-treated TNM alloy solely by exploiting effects of phase transformations and chemical driving forces due to phase imbalances between different heat treatment steps and compares the mechanical properties to those obtained for forged and heat-treated material.

Compensating combustion forces for automotive electromagnetic valves

Electromagnetic actuators show considerable promise in replacing camshafts in automotive combustion engines. Most research published to date focuses on reducing valve seating velocity. This is usually achieved using a current feed-forward controller during most of the valve travel and a trajectory controller with a fixed trajectory close to the end of travel. Such systems face considerable challenges in the presence of varying combustion forces, since the feed-forward strategy cannot ensure constant starting conditions for the tracking controller. The work shown here replaces the feed-forward controller with an energy based feedback controller. For the tracking controller with feedback linearization at the end of the valve travel, real-time trajectories that adapt to different starting conditions are derived. The algorithms can adapt to large changes in combustion pressure without relying on a priori combustion information. The algorithms are validated using simulations and on an experimental test bed.

Ultrasonic-based gas flowmeter for harsh environmental conditions

The applicability of an ultrasonic transit-time gas flowmeter can be extended regarding its gas temperature range (up to 450°C). We used computational fluid dynamics and ray-tracing techniques to investigate thermally-related effects that influence the sound propagation inside the flowmeter. This allowed us to optimize the geometry and the method of how to operate the flowmeter. Our results prove that such a flowmeter can be used to measure pulsating gas flows over wide temperature and velocity ranges such as found in the exhaust gas train of an automotive combustion engine.

A Capacitance Ultrasonic Transducer With Micromachined Backplate for Fast Flow Measurements in Hot Pulsating Gases

A novel high-temperature resistant capacitance ultrasonic transducer is presented. It is designed for an ultrasonic transit-time gas flowmeter and meets two main requirements not fulfilled by common piezoelectric transducers: First, a special construction based on an oxidized and patterned silicon backplate combined with a metallic membrane enables transducer operation at elevated gas temperatures of up to 600 degC. Second, the geometry and material parameters were chosen to obtain a broadband device that allows high signal slew rates and pulse repetition rates. As proven by measurements in an automotive combustion engine test bed environment, this new transducer suits for internal combustion engine exhaust flow measurements in between the catalytic converter and the end of the exhaust pipe. Preliminary results for the exhaust mass flow (up to 160 kg/h) of a typical automotive engine measured with these novel transducers are given and compared with the mass flow calculated from fuel consumption and air/fuel ratio (lambda)

A mechanistic study of the liquid phase autoxidation of nonan-5-one

The liquid phase autoxidation of nonan-5-one has been studied as a model for the degradation of ketones formed from the oxidation of lubricants in automotive combustion engines. The oxidation, at 120 °C, gives a large number of products (32 identified), including derivatives of the substrate with an intact carbon skeleton and low molecular mass compounds, from radical fragmentations, as well as carbon oxides. The products were identified and quantified by GC-MS and GC, with the characterisation of isomers being aided by measuring the deuterium content of products from the autoxidation of 4,4,6,6-[2H4]-nonan-5-one. Products arising from hydrogen atom abstraction from all the secondary C–H bonds were observed, with the main site of attack being α to the carbonyl group. The ketoalkyl, ketoperoxyl and ketoalkoxyl radicals formed in the reaction undergo radical dimerisation, disproportionation and hydrogen atom abstraction. With the ketoalkoxyl radicals the dominant pathway is β-scission, indeed ∼58% of the total product yield arises from this fragmentation of the α-ketoalkoxyl radical. Mechanisms for the formation of the observed products are proposed and used to determine the selectivity of the autoxidation for the different C–H bonds in the substrate.

Evaluating Alternative Internal Combustion Engines: 1950–1975

GMR (General Motors Research Laboratories, now GM R&D Center) has long sought ways to improve automotive combustion engines. Following World War II, considerable effort was also devoted to evaluating new powerplants that embodied different operating cycles from those of the established spark-ignition and diesel engines. Two internal combustion variants receiving attention during the third quarter of the 20th century were the free-piston diesel and the gas turbine. Research on those two alternatives is reviewed. Because their shortcomings were judged to outweigh their advantages, neither has found commercial application in highway vehicles.

Fuel control systems for hydrogen-fueled automotive combustion engines—a prognosis

The state of the art in the field of hydrogen-fueled combustion engines was investigated and conclusions were drawn concerning the future development of fuel control systems for automotive engines using hydrogen as fuel. Assuming the use of modern microprocessor technology together with recently developed linear digital actuators and solenoid operated injectors, basic concepts for fuel control systems were proposed for three mainly used types of combustion engines: gas turbine engine for aircraft propulsion, spark ignition engine for cars and compression ignition engine for vehicles and off-highway equipment. These concepts are based on a liquid hydrogen on-board storage system which seems to be the most feasible for use in the near future.