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A three-dimensional model for a direct injection stratified-charge rotary engine has been employed to study two modifications to the pocket geometry of the engine. In one modification, a pocket is located towards the leading edge of the rotor and is shown to produce recirculation within the pocket and faster burning. In the second modification, a two pocket rotor with two injectors and two spark plugs is studied. It appears that this should result in better utilization of the chamber air. It also appears that both modifications rhould result in higher efficiency of the direct-injected stratifiedcharge rotary engine. However extensive computations are required before a final conclusion is reached and before specific recommendations can be made.

A three-dimensional model is used to compute the flow,sprays and combustion in a stratified-charge rotary engine. Wall temperatures estimated from available measurements are used as boundary conditions for the energy equation. The computations provide local and instantaneous heat fluxes on the rotor and the rotor housing. The instantaneous heat fluxes are integrated in time over one cycle of the rotor to obtain estimates of local cycle averaged heat flux through the rotor and the rotor housing. These are then used as boundary conditions in a thermal analysis of the rotor and rotor housing with known coolant-side flow rates and heat transfer coefficients. The thermal analysis is done using a finite-element three-dimensional code which provides updated estimates of the rotor and rotor housing wall temperatures. These wall temperatures agree within ±20°C of the measured wall temperatures.

Hayes Lemmerz has published papers (Ref 1 and 2 ) where different rotor designs were investigated to increase airflow velocity. We also have published the dynamometer test's data to show the 100 degrees F drop in temperature and 50% drop in deformation in rotors with 5% increase in airflow velocity (Ref 3). In the previous paper (Ref 4), the increase of 37.2% of airflow velocity in a 72 curved fin rotor design, was shown. In this paper, we are showing the results of dynamometer testing the 72 curved fin rotor design. When the 72 curve fin rotor design is compared to current production design, the 72 curve fin rotor design shows, a 140° F (60° C) drop in temperature during heating and cooling cycles. Hayes Lemmerz is testing this rotor design on standard vehicle tests ( LACT and DST). The results of these tests would be presented in another paper.

Hayes Lemmerz has pursued fin configurations in straight and curved fin rotors to achieve high airflow velocity. The largest increase in airflow velocity of 37.2% is achieved by curving fins to a specific entry and exit angle and increasing surface area by increasing fin number. There is a need for funneling air into the narrow entry in the hub area. The new “Hayes Air Director” successfully channels air into the curved fins. Hayes Lemmerz is in the process of casting rotors with curved fins and the air director idea. Dynamometer and vehicle tests will follow. The current renwood model of the rotor design shows 34.8 to 37.2% increase in airflow velocity when tested on the Hayes Airflow machine.

Brake squeal signatures (2 kHz to 18 kHz) have tonal content highly dependent on the specific brake system structural architecture. The challenge in minimizing squeal involves correctly identifying the conditions (temperature, apply pressure, rotor speed as some basic parameters) of occurrence, defining the underlying structural dynamics of the system and applying appropriate suppression solutions. The quantitative metric of improvement is the cumulative event percentage of occurrence. Design variables of the brake system and performance attribute targets extend the challenge beyond the level of just reducing noise. Consideration of material costs, manufacturing/assembly factors, durability, thermal management as well as other factors narrow the solution space significantly. Compressed late stage development is not uncommon in reaching acceptable levels of performance and is a primary reason for following a well defined process flow with provision for alternative solutions.

The effect of rotor alloy composition on thermal conditions in a disc brake system was determined analytically. The three alloys selected were gray cast iron, 356 aluminum, and copper -1% chromium. This study includes calculations of the temperature and heat storage in the various portions of the brake system, as well as the variations of convective heat transfer throughout the system. These computations were made for the transient conditions existing during a series of 60 mph stops (15 ft/sec2 deceleration). The steady-state rotor surface temperature and the thermal gradients were found to decrease with increasing thermal conductivity of the alloys. The rotor surface temperatures for the first two stops were relatively independent of thermal conductivity, but were strongly dependent on heat capacity. Convection was found to occur almost entirely (greater than 90%) from the rotor surface and ventilating passages.

The aim of this work is to characterize the formation of metal pick-ups onto Automotive brake pads, that can lead to major wear problems for the friction material and for the rotors. The characterization of these metal pick-ups has been obtained by means of microscopy techniques (optical microscope and SEM analysis), by X-ray diffraction and thermal analysis, while it has been tried to evaluate the influence of morphological and compositional parameters (like amount of lubricants and of organic compounds) of the pad on the pick-ups formation by performing “true-scale” simulations following specific procedures.

The Nordberg control which programs the power output of a prime mover regardless of external conditions, such as flow of water to the propeller, ship's draft, or number of prime movers geared to shafting is described. The control establishes the quantity of fuel to be used by the prime mover at any set speed, thereby fixing its torque output, and varies the propeller pitch to suit the set speed and programmed torque. It accomplishes this by integrating the action of two governors, one controlling fuel and the other propeller pitch.

The design and performance of a brushless d.c. motor with high power density using ferrite magnets and a two transistor drive is described. The motor utilizes a single-phase operating principle which permits the use of an electronic drive circuit utilizing only two power switching devices, making it cost effective with a conventional d.c. commutator motor using P.W.M. speed control. High power density is obtained by the use of an external rotor construction and a multi-pole format with a concentrated winding. The starting problems normally associated with single-phase motors is addressed and an experimentally proven solution is described. Significant reduction in starting current is achieved as a no cost bonus and significant improvements in overall operating efficiency can be obtained if the power density is reduced to normal auto industry levels.

Thermal judder occurs when differential thermal expansion is experienced around the rotor during a brake application. A temporary circumferential disc thickness variation (DTV) is created which can lead to brake torque variation. The cause of the uneven heating of the rotor can be an imperfection; often a permanent DTV caused by periods of off-brakes contact between pad and disc. Using a dynamometer test combining dynamic disc thickness measurement and pyrometric techniques the evolution of thermal DTV may be studied. It can be demonstrated that increasing thermal DTV is accompanied by increasing brake torque variation. Hot spot formation is also evident but this is shown not be the primary cause of brake torque variation.

A fault detection method with parity equations is proposed in this paper. Due to low cost implementation, the velocity of a motor is not measurable in EPB systems. Therefore, residuals are not reliable with a low resolution encoder to estimate the motor velocity. In this paper, we propose a fault detection method with sensorless estimation using current ripples. The method estimates position and velocity of the motor by detecting periodical oscillations of the armature current caused by rotor slots. This method could estimate position and velocity of the motor with less computational effort than a state observer. Moreover, the method is less sensitive to motor parameters than model-based estimation methods. The effectiveness of this method is validated with experimental data. The simulation results show that various faults have their own residual patterns. Therefore, we could detect the fault by monitoring the residual signals.

The reliability of airborne equipment is related to the thoroughness of the environmental test program. The importance of being able to rationalize the environmental tests in terms of the actual flight environment is stressed. Present environmental vibration test procedures, which are based for the most part on flight data obtained in propeller driven aircraft, are reviewed. It is shown that such procedures cannot be applied to turbojet aircraft. An environmental test procedure is proposed which utilizes the latest type laboratory shaker and control equipment to provide a vibration and noise analogue of an aircraft. The penalties of “over-testing” are pointed out. In conclusion, an environmental test specification is compared to an insurance policy, and it is urged that its implications be fully understood.

Damping plays an important role in controlling brake squeal caused by the coupling between the rotor and the pads. Since most of the damping in the system (during brake squeal conditions) is coming from the pads, it becomes important to understand the relationship between the damping of the pad by itself in its free-free condition and that of the system in terms of braking pressure, temperature, and frequency. This relationship will help in understanding the effects of optimizing the damping of the pad, whether the damping comes from the friction material, backing layer, or add-on damping treatments. The purpose of this paper is to show that the modal strain energy method can be used to arrive at such a relationship.

In the present paper we introduce a monolithic CFD approach to simulate the cooling-down characteristics of disk brakes. To ensure a strong coupling between fluid and solid domain the overall transient thermal problem is solved within a single flow solver during the complete cooling-down process. We employ a fully implicit second order solution procedure. The experimental configuration consists of an inertia dynamometer including a generic 17 inch vented front disk with caliper, dust shield, bearing and knuckle. The validation is carried out for three different air flow velocities, with and without dust shield. The temperature is monitored via two thermocouples embedded into outer and inner rotor cheeks. In order to quantify the cooling-down characteristics, regression analysis are conducted on the temperature curves. The obtained cooling coefficient serves as comparison between measurement and computation.

Electric vehicles are fast expanding in market size, and there are increasing customer expectations on all aspects of the vehicle, including its noise and vibrational characteristics. Irritable noise from traction motors account for around 15% of the overall noise in an electric vehicle, and thus, has a need to be analysed and studied. This study focuses on identifying the critical vibro - acoustic orders for an 8 pole PMSM (Permanent Magnet Synchronous Motor) for three cases - healthy, with static eccentricity and with dynamic eccentricity. PMSM motors are widely used for traction and other applications due to their higher power density along with compact size. A coupled approach between electromagnetic and vibro - acoustic simulation is deployed to characterise the NVH behaviour of the motor.

This year (1989) Mitsubishi Motors Corp. introduced, on some models, a newly-developed Hydraulic Coupling Uint (HCU), by which 2WD vehicles can be converted into 4WD ones in the same way as done by a viscous coupling (VC). This HCU is similar in the configuration to a vane pump: the oil discharge is returned to the suction chamber through a number of orifices. The rotor and cam ring (housing) are respectively connected to the two shafts; either of the one with the front wheels and the other with the rear wheels. Accordingly, it works as a slip-sensitive differential like a VC while it has a merit of progressive and parabolic torque-response characteristic, which offers stronger traction and acceleration capability and also minimizes tight-corner braking. This paper discusses primarily the configurations, functions and test results of the HCU and also presents an overview on further development possibilities of the 4WD system.

This paper describes the details of realization and the test results of a new 1000KW - 2500RPM - 21 liter Hyperbar engine developped and constructed for the propulsion of 60 tons coast guard ships, having two fixed pitch propellers. The torque characteristics of these engines ensure the ship to be propelled between 28 and 6 knots under continuous operation without overheating, smoke and fouling, and without using any auxiliary propulsion unit for slow cruising speed. The performances, including fuel consumption are reported under various operating conditions.

The benefits of energy and operational cost savings from using copper rotors are well recognized. The main barrier to die casting copper rotors is short mold life. This paper introduces a new approach for manufacturing copper-bar rotors. Either copper, aluminum, or their alloys can be used for the end rings. Both solid-core and laminated-core rotors were built. High quality joints of aluminum to copper were produced and evaluated. This technology can also be used for manufacturing aluminum bar rotors with aluminum end rings. Further investigation is needed to study the lifetime reliability of the joint. The improvement of manufacturing fixture through prototype test is also required.

This paper proposes a new multi air gap motor with trench-shaped coil. The proposed motor has high torque without rare earth magnets compared to conventional single air gap motors due to its multiple air gap and ferrite permanent magnet (PM) assisted segment rotor poles. Firstly, the basic structure and features of proposed motor is shown: three stator cores, integrated a set of three phase windings, and an annular rotor core with magnetic saliency at three sides and ferrite magnets. Then, the performance of proposed new motor and well-known single air gap IPMSM with rare earth magnet are compared by FEA. Secondly, the simple winding method similar to the conventional motor is clarified. Next, practical design of the 3-D magnetic circuit with laminated steel is discussed. Eddy current generated by the magnetic flux passing through the laminated steel in the core stacking direction is focused, and methods for reducing eddy current loss are shown.

Modern high-cycle fatigue criteria were implemented in structural wind turbine parts using finite element method. As a result of a test carried out for two fatigue criteria, it was concluded that the Dang Van hypothesis has more conservative results than S-N method. The complete algorithm of the fatigue calculation was illustrated by applying the proposed procedures to a wind turbine hub which is subjected to multi-axial, non-proportional and non-constant amplitude high-cycle loadings and then a structural optimization method is used to reduce the weight and moment of inertia of the wind turbine rotor. ANSYS Workbench and nCode design life are used in the structural and fatigue modeling of the hub.