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1.0 During the warm up process of the coolant in automotive heater systems physical properties such as the density, dynamic viscosity, kinematic viscosity, specific heat and thermal conductivity vary with temperature. To conduct any heater analysis, therefore, it is essential that such variations with temperatures be evaluated. In the present paper a comprehensive literature search is conducted for the published physical properties of the automotive coolants ethylene glycol and propylene glycol. The data are analyzed and compared, and equations describing the variation of the above named physical properties with temperature are derived and presented. The effect of the temperature on the internal heat transfer coefficient is discussed. A comparison of the heat transfer performance between the two glycol coolants is presented. The temperature range studied extends from - 35 to at least 125 degree Celsius.

Knock correction is the spark angle retard applied to the optimum ignition timing to eliminate knock. In adaptive knock control, this amount of spark retard at an operating point (i.e. Speed, load) is stored in a speed/load characteristic map. It will be reused when the engine is operated in this range once more. In this paper, a method to learn the knock correction values into a speed/load characteristic map is described. This method proportionally distributes the knock correction into the characteristic map according to the distance between the speed/load of these nodes and the current operating point. The distributed knock correction value is filtered and accumulated in its adjacent nodes. Simulation examples demonstrate that the retrieved values from the map by the proposed method are smoother than those produced by the method of [2][3]. The mathematical basis for this method is developed. The one and two independent variable cases are illustrated.

A coupled vibration and pressure loading procedure has been developed to perform a CAE virtual test for engine air intake manifolds. The CAE virtual test simulates the same physical test configuration and environments, such as the base acceleration vibration excitation and pressure pulsation loads, as well as temperature conditions, for design validation (DV) test of air intake manifolds. The original vibration and pressure load data, measured with respect to the engine speed rpm, are first converted to their respective vibration and pressure power spectrum density (PSD) profiles in frequency domain, based on the duty cycle specification. The final accelerated vibration excitation and pressure PSD load profiles for design validation are derived based on the key life test (KLT) duration and reliability requirements, using the equivalent fatigue damage technique.

In today's search for a better fuel economy and lower emissions, it is essential to precisely control the injected fuel quantity, as demanded by the engine load, into each of the engine cylinders. In fuel injection systems, the pressure pulsations due to the rapid opening and closing of the injectors can cause uneven injected fuel amounts between cylinders. In order to develop effective techniques to reduce these pressure pulsations, it is crucial to have a good understanding of the dynamic characteristics of such fuel injection systems. This paper presents the benefits of using simulation as a tool to analyze the dynamic behaviors of a V8 gasoline injection system. The fuel system modeling, based on a one-dimensional (1D) lumped parameter approach, has been developed in the AMESim® environment. The comparison between the simulation results and the experimental data shows good agreement in fluid transient characteristics for both time and frequency domains.

Engine air filtration technologies currently used in air induction systems typically utilize pleated paper or felt type air filters. These air filter designs have been used for many years in panels, cylindrical or round (pancake type) type air cleaners. Pleated air filters are specifically designed to be serviceable and hence their performance is inherently limited by vehicle under-hood packaging and manufacturing constraints. Due to these constraints, majority of air cleaner designs are not optimized for engine filtration and air flow management under the hood. Studies show that use of low performing serviceable aftermarket air filters significantly affect the performance and durability of engine air cleaners [9]. High mileage studies confirm that engine durability, service issues, warranty field returns and customer satisfaction was affected by use of aftermarket filter brands.

Modern automobiles utilize stabilizer bars to increase vehicle roll stiffness. Stabilizer bars are laterally mounted torsional springs which resist vertical displacement of the wheels relative to one another. A stabilizer bar is constructed in such a way that it will meet package constraints and fatigue requirements. In order to design a robust stabilizer bar, Taguchi's “Design of Experiment method” is used. The objective of this paper is to develop a robust stabilizer bar design that will maximize the fatigue life and the roll stiffness while minimizing weight. This study is based on results obtained by CAE analysis.

Plastic air induction system (AIS) has been widely used in vehicle powertrain applications for reduced weight, cost, and improved engine performance. Physical design validation (DV) tests of an AIS, as to meet durability and reliability requirements, are usually conducted by employing the frequency domain vibration tests, either sine sweep or random vibration excitations, with a temperature cycling range typically from -40°C to 120°C. It is well known that under high vibration loading and large temperature range, the plastic components of the AIS demonstrate much higher nonlinear response behaviors as compared with metal products. In order to implement a virtual test for plastic AIS products, a practical procedure to model a nonlinear system and to simulate the frequency response of the system, is crucial. The challenge is to model the plastic AIS assembly as a function of loads and temperatures, and to evaluate the dynamic response and fatigue life in frequency domain as well.

Evaporators for automotive air-conditioning systems are being coated externally to improve corrosion resistance, water drainage, and reduce potential odor concerns. The coating durability and efficiency in achieving its corrosion resistance depends on the coating uniformity and adhesion characteristics. Good coating adhesion on aluminum surface can be achieved after freeing the surface from the oxide and flux residues. Evaporators manufactured by the Controlled Atmosphere Brazing (CAB) process have flux residue remaining on the surface, the presence of which interferes with the coating process and also affects the performance of coated components. A methodology to quantify the effect of high Nocolok flux residue on heat exchanger coating uniformity has been presented.

Internal combustion engines are designed to maximize power subject to meeting exhaust emission requirements and minimizing fuel consumption. However, the usable range of ignition timing is often limited by knock in the advance direction and by combustion instability (partial burn and misfire) in the retard direction. This paper details a retard limit management system utilizing ionization signals in order to maintain the desired combustion quality and prevent the occurrence of misfire without using fixed limits. In-cylinder ionization signals are processed to derive a metric for combustion quality and closeness of combustion to partial burn/misfire limit, which is used to provide a limiting value for the baseline ignition timing in the retard direction. For normal operations, this assures that the combustion variability is kept within an acceptable range.

Maximum Brake Torque (MBT) timing for an internal combustion engine is the minimum advance of spark timing for best torque. Traditionally, MBT timing is an open loop feedforward control whose values are experimentally determined by conducting spark sweeps at different speed, load points and at different environmental operating conditions. Almost every calibration point needs a spark sweep to see if the engine can be operated at the MBT timing condition. If not, a certain degree of safety margin is needed to avoid pre-ignition or knock during engine operation. Open-loop spark mapping usually requires a tremendous amount of effort and time to achieve a satisfactory calibration. This paper shows that MBT timing can be achieved by regulating a composite feedback measure derived from the in-cylinder ionization signal referenced to a top dead center crank angle position. A PI (proportional and integral) controller is used to illustrate closed-loop control of MBT timing.

Spark timing of an Internal Combustion (IC) engine is often limited by engine knock in the advanced direction. The ability to operate the engine at its advanced (borderline knock) spark limit is the key for improving output power and fuel economy. Due to combustion cycle-to-cycle variations, IC engine combustion behaves similar to a random process and so does the engine performance criteria, such as IMEP (Indicated Mean Effective Pressure), and knock intensity. The combustion stability measure COVariance of IMEP assumes the IMEP is a random process. Presently, the spark limit control of IC engines is deterministic in nature. The controller does not utilize any stochastic information associated with control parameters such as knock intensity for borderline spark limit control. This paper proposes a stochastic limit control strategy for borderline knock control. It also develops a simple stochastic model for evaluating the proposed stochastic controller.

To obtain the maximum output power and fuel economy from an internal combustion engine, it is often necessary to detect engine knock and operate the engine at its knock limit. This paper presents the ability to detect knock using in-cylinder ionization signals on a large displacement, air-cooled, “V” twin motorcycle engine over the engine operational map. The knock detection ability of three different sensors is compared: production knock (accelerometer) sensor, in-cylinder pressure sensor, and ionization sensor. The test data shows that the ionization sensor is able to detect knock better than the production knock sensor when there is high mechanical noise present in the engine.

This paper describes the applicability of optical imaging techniques to the analysis of the scratch resistance of automotive interior plastic materials. The evaluation of so-called “finger testing” has traditionally relied upon human vision for detection of the initial scratch position. Commonly performed under uniform and defined illumination conditions, the relative contrast difference signified by whitening on a surface as determined by unaided human vision is a highly variable subjective perception; thus individual inspectors may determine the “whitening” point differently. This paper compares test data obtained from both visual and instrumental evaluation methods and discusses the advantages of optical imaging techniques for surface defect analysis.

A suction line heat exchanger (SLHX) transfers heat from the condenser outlet to the suction gas. In a TXV (thermostatic expansion valve) system, the performance improvement with a 60 to 80 % effective SLHX is expected to be on the order of 8 to 10 % for capacity, and 5 to 7 % for COP for high outdoor air temperatures of 43ºC. In a FOT (fixed orifice tube) system, the performance improvement was calculated to be about 10 to 15 %. The calculated improvements have been verified experimentally within a few percent.

The stand alone oil to air (OTA) transmission cooling strategy with thermostatic cold flow bypass valve has been shown to be an effective means of improving the warmup of an automatic transmission. Improving the system warmup rate of an automatic transmission significantly improves its efficiency by reducing losses resulting from extremely viscous transmission fluid and can allow for calibration changes that improve overall transmission performance. Improved transmission efficiency in turn allows for improved engine efficiency and performance. The improvements obtained from increased transmission and engine efficiency result in an overall increase in vehicle fuel economy. Fuel economy and consumption are important parameters considered by the vehicle manufacturer and the customer. Fuel economy can be considered as important as reliability and durability.