Automotive Requirements

When thermoplastic dynamic seals are designed for automotive applications, perhaps the most important parameter is the PV (pressure and velocity) value. PV is 

The coefficient of thermal expansion must also be accounted for in design calculations. The normal operating temperature for transmission applications is 120°C. A material must be able to operate at this temperature and not expand to a greater volume than the mating parts allow. The coefficient of friction (p) of the material should be considered as well when designing a dynamic seal. Rotating shafts require a lower value for p in order to reduce wear. 

Production of automobiles is in the millions of units per year, so cost is a severe factor. A compression molded polyimide, for instance, is typically on the order of 0.33 per seal. However, this cost becomes insignificant given that these dynamic seals are located deep within the interior of the transmission, and thus labor for disassembly and time will make the cost of a failure quite severe. 

When an automotive chemist chooses a polymer for dynamic sealing, he or she will have to consider the conditions present in Table 6.1. The two main polymers utilized today for these applications are the thermoset polyimides and polyetheretherketones. Polytetrafluoroethylene is also used for less severe applications. Wear test data are collected on an apparatus in which three circular pins of the polymer being examined 

Pressure in the radial direction Differential line pressure Typical seal diameter Typical cross section Operating temperature Lube 

---

This trade-off may not even occur in some cases. Membranes used in the PEMFC have been developed for the chlor-alkali industry and have 40,000-hour durability (shutdowns are prohibitively expensive in stationary applications), require only 5,000-hour durability (corresponding Co 100,000 miles) for automotive applications. Hence, it maybe possible to develop less expensive membranes that still meet automotive requirements. 

The schedule for the program requires considerable discipline to identify research requirements to support candidate technologies, to monitor progress relevant to automotive requirements, and to focus... 

In Fig. 4.6 a scheme of cooling circuit related to FCS for automotive application is shown. The main components are the pump for liquid circulation, the water reservoir and the heat exchanger with fan. For small size stacks (from 100 to 500 W) it is possible to use only air forced by fan to cool directly the stack, while for higher powers, more suitable for automotive requirements (1-100 kW), it is reasonable to use an internal coolant circuit fed by a liquid, such as de-ionised water or ethylene glycol-water mixtures, to improve the heat removing capacity of an order of magnitude with respect to the gas. 

To meet the automotive requirements the design of the high-pressure sensor plays a decisive role with respect to the measurement task. Fig. 7.4.7 shows a cross section of a pressure sensor for gasoline direct injection systems. 

There are means other than SAS for counting several revolutions of a steering wheel, either mechanically or electrically. The electronic controls around an SAS must fulfill the automotive requirements low current consumption, wake-up functions, and EMC requirements among others. When the SAS is integrated into the controls on top of the steering column (top column module, TCM) it has to share microcontroller resources and has to fit into the TCM architecture. The de-... 

Freezing can be viewed as a special case of degradation requiring hundreds of repetitive freeze storage and freeze start-ups to meet automotive requirements. Therefore, this area is subject to the same limitations of costly and time-consuming tests, and relative absence of in situ structural and compositional measurement methods. The result of this situation is a challenging and varied opportunity for fundamental research and discovery (Figure 2). 

TABLE 9.1 Typical Automotive Requirements Met by Fully Cross-Linked TPV... 

Bonding rubber to a solid insert as part of the injection moulding was a process first begun in the 1960s. Since that era the process has become, like rubber processes in general, a science rather than the black art as it was once regarded. The process does need to be closely controlled to ensure 100% compliance with automotive requirements. This chapter will help the reader understand the processes and how components can be produced that will surpass the customers expectations [1,2]. 

Automotive requirements for plastic fuel systems need protection against static discharge. There is also a demand for antistats in the chemical process industry because of ftammable liquids,... 

Keywords automotive, automotive application, car components, automotive requirements, substitution of metals and polymers, interior parts, exterior parts, electrical applications, filled PP, elastomer-modified PP, thermoplastic polyolefins (TPO), GMT-PP, long-fiber reinforced PP, composites, market trends, glass fiber (GF) reinforcement. 

The thermosetting films are employed for metal-to-metal bonding in aircraft, as well as less demanding appliance, electrical, and automotive requirements. These adhesives are hybrids designed to provide an optimum combination of shear strength, elongation, and heat resistance. Nitrile-phenolic and epoxy-nitrile are the leaders, followed by vinyl butyral-phe-nolic, epoxy-nylon, and epoxy-phenolic. The nitrile rubber in the epoxy-nitrile is a carboxyl-terminated butadiene-nitrile polymer which reacts with the epoxy at the elevated cure temperature. 

Assuming 10 s of hot time per stop, this necessitates catalyst support durability at 1.2 V of around 100 h with less than 30 mV drop in performance at 1.5 A cm l Similarly, it was estimated that the idle time of the stack at cathode potentials of approximately 0.9 V could amount to several thousand hours over the vehicle life. The data at 80 °C predict that standard Vulcan carbon supports do not meet automotive requirements with respect to start/stop, as well as prolonged idle conditions. 

While efforts to minimize freezing and maximize the rate at which stacks can self-heat during startup can improve performance of startup after short shutdowns, they are insufficiently robust to meet automotive requirements. A stack that operates at lower relative humidity, if such operation were enabled by novel... 

---