Refine Your Search




Search Results

Training / Education

Introduction to Commercial and Off-Road Vehicle Cooling Airflow Systems

Vehicle functional requirements, emission regulations, and thermal limits all have a direct impact on the design of a powertrain cooling airflow system. Given the expected increase in emission-related heat rejection, suppliers and vehicle manufacturers must work together as partners in the design, selection, and packaging of cooling system components. An understanding and appreciation of airflow integration issues and vehicle-level trade-offs that effect system performance are important to the team effort. The severe duty cycles, minimal ram air, and sometimes unconventional package layouts present unique challenges.

Neural Network-based Optimal Control for Advanced Vehicular Thermal Management Systems

Advanced vehicular thermal management system can improve engine performance, minimize fuel consumption, and reduce emissions by harmoniously operating computer-controlled servomotor components. In this paper, a neural network-based optimal control strategy is proposed to regulate the engine temperature through the advanced cooling system. Presenter Asma Al Tamimi, Hashemite University

Cooling Airflow System Modeling in CFD Using Assumption of Stationary Flow

Today CFD is an important tool for engineers in the automotive industry who model and simulate fluid flow. For the complex field of Underhood Thermal Management, CFD has become a very important tool to engineer the cooling airflow process in the engine bay of vehicles. Presenter Peter Gullberg, Chalmers University of Technology

High Speed Machining of CFRP Parts

High Speed Machining of CFRP Parts Investigation of the influence of new geometries, cutting datas and coolant capabilities on the surface finish of CFRP parts. State of the art: Different CFRP grades and machining conditions make geometry adjustments to the tool necessary. Mechanical failures through machining operations can be avoided in most of the cases. New unidirectional CFRP grades and dry machining processes again lead to machining problems. This study investigates new geometries to avoid heat damage with dry maching and air coolant in case of unidirectional CFRP. With help of a thermo camera and the surface investigation with a scanning electron microscope, heat damage can be analysed and therefore new geometries can be developed and tested. Target is to develop a new multi purpose CFRP geometry to meet the requirements of the future. The reduction of different geometries used leads to major cost savings. Presenter Ingo von Puttkamer, Guhring oHG
Training / Education

Introduction to Cooling Airflow Systems Web Seminar RePlay

Vehicle functional requirements, diesel emission regulations, and subsystem thermal limits all have a direct impact on the design of a powertrain cooling airflow system. Severe duty cycles, minimal ram air, fouling, and sometimes unconventional package layouts present unique challenges to the designer. This course introduces many airflow integration issues and vehicle-level trade-offs that effect system performance and drive the design. The goal of this course is to introduce engineers and managers to the basic principles of diesel cooling airflow systems for commercial and off-road vehicles.
Technical Paper

Numerical Investigation of Narrow-Band Noise Generation by Automotive Cooling Fans

Axial cooling fans are commonly used in electric vehicles to cool batteries with high heating load. One drawback of the cooling fans is the high aeroacoustic noise level resulting from the fan blades and the obstacles facing the airflow. To create a comfortable cabin environment in the vehicle, and to reduce exterior noise emission, a low-noise installation design of the axial fan is required. The purpose of the project is to develop an efficient computational aeroacoustics (CAA) simulation process to assist the cooling-fan installation design. This paper reports the current progress of the development, where the narrow-band components of the fan noise is focused on. Two methods are used to compute the noise source. In the first method the source is computed from the flow field obtained using the unsteady Reynolds-averaged Navier-Stokes equations (unsteady RANS, or URANS) model.

Principles of Engine Cooling Systems, Components and Maintenance

Completely revised as a result of the significant progress made in cooling system design and maintenance practices and procedures, HS-40 provides current, comprehensive information on the description, function, and maintenance of engine liquid-cooling systems used in light and heavy-duty vehicles. Information-packed chapters discuss the interrelation between the cooling system and other engine systems, cooling system components, general preventive maintenance, and troubleshooting.
Technical Paper

Prevention of Corrosion in Duralumin Airplane Structures

AT first believed immune, aluminum alloys have been found extremely susceptible to both surface corrosion and intercrystalline corrosion. The latter goes on under paint that has been applied to imperfectly cleaned surfaces, and shows only as blisters. Because of this, it has become commonplace to break with the fingers the ribs and the trailing edges of duralumin lower wings and tail-surfaces. Contact of duralumin with brass or steel hastens corrosion, and protective paint coverings are dissolved by dope where fabric surfaces meet metal parts. All-duralumin structures are not considered suitable for sea-going aircraft unless all joints and seams are of water-tight construction, not only in hulls but in other members of the structure. Corrosion over the land is much less severe. Few manufacturers seem awake to the importance of corrosion. The fight to avoid it should begin with avoiding seams that are difficult to protect and hollow members that cannot be sealed hermetically.
Technical Paper

Specification-Writing for Petroleum Lubricants

ALL large users of petroleum lubricants are endeavoring to reduce to printed form their individual ideas of what the lubricants they want should contain and what their physical and mechanical properties should be. The lubricants manufacturer finds, however, that anarchy prevails among the requirements and that the technique of writing the specifications is distinctly amateurish. One method followed is to analyze a satisfactory lubricant and embody the results in the specifications, but the specifier does not know that the product is the best for his purpose and does not possess the facilities for accurate analysis and the ability to determine the pertinent from the irrelevant factors. Another method is to select from a number of analyses and specifications items that seem important and incorporate them in the writer's specification. The result calls for a non-existent hybrid that may be impossible to produce.
Technical Paper

Front-Wheel Drives

ENGINEERING considerations leading to the former almost universal practice of steering with the front wheels and driving and braking with the rear wheels are reviewed, and the desire for bodies lower than can be made with conventional design is given as the main reason for the present interest in front drives. For early history, European development, racing practice and the closely related subject of four-wheel drives, the reader is referred to a previous paper by Herbert Chase.2 One major advantage to be secured with front-drive design is lower unsprung weight, which should promote easy riding and road-holding ability and reduce tire wear. An inherent disadvantage is that driving-torque reaction and hill climbing shift some weight from the front axle to the rear axle, thus slightly reducing the tractive effort possible; but this shift is not considered important, since the control of weight distribution is in the hands of the designer.
Technical Paper

Engine Cooling

FROM 25 to 35 per cent of the heat energy of the fuel inducted into the cylinders of an internal-combustion engine must be eliminated by the cooling system. As this waste requires the expenditure of energy, the devising of an efficient cooling system is imperative. The author, who is a leading American authority on engine problems, discusses the theory of liquid-cooling, gives heat-transfer and temperature-balance equations that must be satisfied and points out the three interrelated variable factors that must be incorporated in their most economical relation. The cooling system must be studied as a whole, rather than from the standpoint of any particular unit. Some commonly held beliefs regarding fans, fuel-pumps and oil-temperature control are controverted. Five elements necessary for an efficient cooling system are enumerated.
Technical Paper

Frame Design and Front-End Stability

EXPERIMENTAL work done to ascertain the influence of frame and body structures upon front-end stability of the automobile is described by the author and definite means of preventing the phenomena of wheel wabble, shimmy and vibratory movements of the radiator, head-lamps and fenders are set forth. Early investigation showed that the problem involved not only the unsprung portions of the car but also the structural arrangement of the frame and the body. Chassis-dynamometer tests revealed a nodal point of zero torsional vibration approximately at a plane through the front seat but varying with different cars and body types, the forward portion of the chassis vibrating torsionally about the longitudinal axis in opposite phase to the rear portion. Experiments rather conclusively proved that damping is needed in the frame and body.
Technical Paper

Gaging Airplane-Engine Performance

WHILE virtually all aircraft builders agree in placing reliability as the most important factor in gaging engine performance, from there on agreement is lacking. The author believes that all factors exclusive of reliability can be evaluated so as to provide a good basis for choosing an engine. These factors include durability, which despite the opinion of some aeronautic engineers is not synonymous with reliability; weight per horsepower of the complete powerplant, including radiators and cowling; head resistance; fuel consumption; and first cost. The effect of changes in engine weight on operating cost are discussed, the text being supplemented by tables showing the effect of increased engine-weight, operating cost and the operation-expense items that are affected.
Technical Paper

Development of the Franklin Direct Air-Cooled Engine

FEATURES of the design of the various cylinders built by the Franklin organization in its development program leading up to the present design are discussed in this paper. The relation of waste heat to cooling-fin areas and cooling-blast velocities is shown and discussed for cylinders up to 3½-in. bore. Characteristics of the cooling system, including fan, fan housing and air housings, are discussed at length, and the authors contend that no more power, if as much, will be absorbed in the cooling system as in that of the indirect air-cooled engine. Results of tests showing the ability of the engine to cool under the severest conditions of load and temperature are given. Since the quietness of any engine is dependent upon constant valve-clearances, the authors describe in detail the method followed in the Franklin design to maintain at less than 0.003 in. any variation in clearance. A careful analysis is made for each part in the valve-gear mechanism that is affected by expansion.
Technical Paper

Reducing Horsepower and Noise of Automotive Cooling-Fans

STATING the automotive cooling-fan problem as being constituted of the delivery of more air, decrease of fan horsepower, reduction of fan noise so that it is comparable with or less than other powerplant noises and the installation of the fan in a restricted space, the author describes the testing apparatus and method used in analyzing the subject. Fan speeds and the most effective number of blades are then considered, followed by analyses of fan diameter and pitch and curvature of fan blades. The manner in which air is discharged from the fan and the adaptation of a fan to an automobile are also discussed. Following statements concerning the desirable number of fan blades and blade spacing, noise characteristics of fans are analyzed in detail as a preface to the author's consideration of means of reducing fan noise, and a summary listing the conclusions reached as a result of the study is appended.
Technical Paper

Recent Developments in Poppet Valves

AFTER stating that increased speed, mean effective pressure and piston displacement of engines have made valve conditions more difficult during the last few years, the author recalls the path which development has followed by a brief list of materials and methods of cooling. Where the stem joins the head is the hottest part of the valve. A shield for this point is shown, also a shroud to protect the end of the valve-stem guide. Cooling the valve increases its life. Salt and sodium cooling are compared, and methods of sealing the coolant in place are described. The construction and behavior of copper-cooled valves are illustrated and recounted, and a one-piece hollow-head valve is described. Reasons for valve-seat inserts are given.
Technical Paper

The Cooperative Fuel-Research Committee Engine

AFTER stating the three qualifications that should be possessed by a fuel-testing engine as (α) universality, (b) ruggedness and (c) low cost, the way in which all are met is outlined. The construction of the original engine is described in some detail and a table of dimensions of the more important parts given. Refinements that were developed as a result of work with the original engine in the last 2 years affect water-jacketing, condenser-coil location and accessibility of certain parts. To overcome objections raised as a result of actual experience in fuel testing by members of the Cooperative Fuel-Research Committee, the engine has been recently redesigned to include a variable-compression cylinder, a modified centrifugal type of water pump and magneto-ignition. These changes are described and the reasons for their incorporation in the engine are stated. Illustrations and drawings showing various stages in the development of the engine supplement the text.
Technical Paper


In the first part of the paper, a general quantitative comparison of air, water and oil-cooled cylinders is given as it relates to the subject of heat-transfer and temperature drop. Unfortunately, the discussion does not include experimental data, but the assumptions are stated clearly and a large range of values is covered in Table 2 so that any desired values can be chosen. A thorough and comprehensive discussion of the steam or the radio-condenser type of cooling is given under the headings of Steam Cooling Systems, Characteristics of Steam Cooling Systems, Cooling Capacity of Radiators Used To Condense Steam and Present State of Development. In the second part, an attempt is made to give a thorough but brief discussion of the performance or of the operating characteristics of radiators from the point of view of the car, truck or tractor designer. The cooling of aircraft engines is not considered.
Technical Paper


The magnitude of the business of the American Railway Express Co. requires that careful consideration be given to the details necessary for economical operation. The equipment comprises 12,755 vehicles, of which approximately one-third are motor-driven and have a carrying capacity of more than one-half the total. On July 1, 1918, when all the express companies were merged into one organization, it was found that the motor-vehicle equipment included 59 different makes and 131 different models. Among the 377 trucks built by one company were 21 different models. Diversity of equipment, of course, complicates the maintenance problem and adds to the cost. Additional expense is incurred frequently by purchasing and experimenting with parts offered by makers of accessories such as carbureters, spark-plugs, wheels and the like. Careful inspection, adequate lubrication and the adoption of “stitch-in-time” methods will save needless expense.