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Accuracy of numerical simulation has to be evaluated through the actual phenomenon such as experiment or measurement and then it can be employed to design the air-conditioning system of car cabin at the development phase. Scaled model of vehicle cabin was created by the Society of Automotive Engineers of Japan (JSAE) and the experiment was performed to obtain the detailed information of heat transfer characteristics inside the cabin under the non-isothermal condition. The sheet heaters were put to the inner surface of the acrylic cabin and they supplied certain amount of heat. The temperatures of inner and outer surface and air were measured to evaluate the thermal environment of the cabin. The results lead to enhancement of the data of the standard model of the cabin.

The combination of 1D and 3D fluid flow models is achieved using a co-simulation methodology. This realizes that the internal flow in a component simulated in 3D is incorporated into a network (system) containing components represented in 1D. This methodology gives the details of the internal flow while conserving overall mass flow in the system, thus eliminating uncertainties in boundary conditions prescribed in the 3D model and reducing the overall simulation time. This paper shows numerical results for internal flow of water flow circuit of engine cooling system and availability and current problem of 1D/3D co-simulation method are discussed.

The results of thermal and flow studies for a ¼ scale model of an engine compartment are presented here. Using PIV and thermocouples, the mid-plane flow velocity and temperature of the buoyant underhood flow with engine block average surface temperature of 127°C and exhaust heaters (surface temperature ∼ 600°C) were measured. Thermocouples were also used to measure the steady-state temperature of the engine block surface and the enclosure outside and inside walls. The airflow in the engine compartment is steady, laminar and three dimensional as predicted by the Grashof and Reynolds numbers calculated for different simple geometries comprising the engine block and its exhausts. Three dominant vortices are found to exist at the top corners of the engine compartment. Thermal measurements on the engine block and enclosure surfaces support the temperature gradients expected given the specified geometry and boundary conditions.

The intention of this work is to illustrate a method used to overcome limitations of tire models developed during an evaluation study of an Empirical Dynamic™ (ED) damper model. A quarter vehicle test system was built to support the evaluation, and a model of the test system was also developed in ADAMS™. In the model, the damper was represented by a polynomial spline function and by an ED model separately. Vehicle level comparisons between the physical measurements and the model predictions were conducted. The actuator displacement signal from the physical test was used to drive the virtual test system. Spindle acceleration, spindle force, and other signals were collected for comparison. The tire model was identified as a significant source of error and as a result, the direct vehicle level correlation study did not illustrate any advantage of the ED damper model over a spline damper model.

4-Post durability test simulations using a nonlinear FEA model have been executed by engineers responsible for structural durability performance and validation. An integrated Body and Chassis, full FEA model has been used. All components of the test load input were screened and only the most damaging events were incorporated in the simulation. These events included the Potholes, Belgian Block Tracks, Chatter Bump Stops, Twist Ditches, and Driveway Ramps. The CAE technology Virtual Proving Ground (eta/VPG®*) was used to model the full system and the 4-Post test fixtures. The nonlinear dynamic FE solver LS-DYNA** was used in this analysis. The fatigue damage of each selected event was calculated separately and then added together according to the test schedule. Due to the lack of stress/strain information from hardware test, only the analyzed fatigue damage results of the baseline model were scaled to correlate with physical test data.

The Representative Interactive Flamelet (RIF) - model has established itself as a model well suited for capturing conventional non-premixed combustion in diesel engines. There are concerns about applying the concept to model combustion modes characterized by high degrees of premixing, since it is argued that the fast-chemistry assumption, on which the model is based, breaks down. However, the level of premixing at which this occurs is still not well established. In this paper the model is successfully applied to the so-called Premixed Charge Compression Ignition (PCCI) mode of combustion, characterized by relatively early injection timings, high EGR, and cooled intake air. For very advanced injection timings, an alternative modeling approach is developed.

A novel design tool that produces solid model geometry from computer-generated sketches was developed to dramatically increase the speed of component development. An understanding of component part break-up and section shape early in the design process can lead to earlier part design releases. The concept provides for a method to create 3-dimensional (3D) solid models from 2-dimensional (2D) digital image sketches. The traditional method of creating 3-dimensional surface models from sketches or images involves creation of typical sections and math surfaces by referencing the image only. There is no real use of the sketch within the math environment. An interior instrument panel and steering wheel is described as an example. The engineer begins with a 2-dimensional concept sketch or digital image. The sketch is scaled first by determining at least three known feature diameters.

Knock noise induced by automotive shock absorbers has serious influence on driving comfort and vehicle quality. Some research focusing on knock noise had been introduced in the past. However there is the unidentified phenomenon that has been unnoticed. This paper describes the new theory to clarify one of the unidentified phenomenon and proposes the equation for stability assessment which is useful on designing stage of development. First of all, the characteristics of the unidentified rod vibration of shock absorbers are investigated experimentally. Second, the new theory is established on the basis of the non-linear physical model with friction forces between piston and cylinder. This theory shows that the unstable vibration, so called the Self Excited Vibration, can be induced by not only friction property but also structure of rod and piston. Third, the equation for stability assessment, which is useful on designing stage of development, is proposed on the basis of new theory.

A new generation Northstar DOHC V8 engine has been developed for a new family of rear-wheel-drive (RWD) Cadillac vehicles. The new longitudinal engine architecture includes strategically selected technologies to enable a higher level of performance and refinement. These technologies include four-cam continuously variable valve timing, low restriction intake and exhaust manifolds and cylinder head ports, a steel crankshaft, electronic throttle control, and close-coupled catalysts. Additional design features beyond those required for RWD include optimized block ribbing, improved coolant flow, and a newly developed lubrication and ventilation system for high-speed operation and high lateral acceleration. This new design results in improved performance over the entire operating range, lower emissions, improved fuel economy, improved operating refinement, and reduced noise/vibration/harshness (NVH).

A vehicle concept finite-element model is experimentally assessed for predicting structural vibration to 50 Hz. The vehicle concept model represents the body structure with a coarse mesh of plate and beam elements, while the suspension and powertrain are modeled with a coarse mesh of rigid-links, beams, and lumped mass, damping, and stiffness elements. Comparisons are made between the predicted and measured frequency-response-functions (FRFs) and modes of (a) the body-in-white, (b) the trimmed body, and (c) the full vehicle. For the full vehicle, the comparisons are with a comprehensive set of measured FRFs from 63 tests of nominally identical vehicles that demonstrate the vehicle-to-vehicle variability of the measured FRF response.

A 3D dynamic model has been developed to investigate the dynamic response of a finger-follower cam system by considering the interaction between valve train and camshaft. The torsional moments being different for each cam cause the torsional vibrations of the camshaft. The resulting speed fluctuations of the cam affect the dynamics of other valve train components including the ultimate valve motion. To better represent the critical parts of the valve train, special attention was given to the cam and follower and to valve springs. The cam and follower are treated as a force contact relation so parts can separate and impact again. The valve springs are now treated as flexible bodies and important mass effects and coil contact events are captured during the simulation. The mass effects are associated with spring surge that occurs at high speed. Coil contact occurs when the individual coil in the spring collides. One bank of a V6 engine with overhead twin cams is modeled in this study.

The 4T65-E transmission produced by General Motors is the third evolution of GM's original 4-speed F.W.D. automatic. This most recent redesign introduced for the 1997 model year meets new corporate goals for fuel economy and reduced noise, along with the ability to adjust shift character to meet the brand image of the various nameplates. Improving fuel economy and cooling at increased engine power levels was enabled by designing a larger diameter torque converter with the aid of 3-D modeling. The new converter has reduced internal leakage and incorporates a controlled slip clutch. Improvements in NVH have been achieved through a revised oil pump design and the use of the new phased drive chain, made affordable by the joint development of powdered metal technology required for the unique sprocket design.