Low Speed Pre-Ignition (LSPI), also referred to as Stochastic Pre-Ignition (SPI), Superknock or Megaknock is an undesirable combustion phenomenon that limits the fuel economy, drivability, emissions and durability performance of modern turbocharged gasoline engines. Numerous studies have previously reported that the frequency of LSPI is sensitive to engine oil composition. One of these drivers is the concentration of Calcium, which is usually delivered in the form of a detergent in the additive package. Switching to completely all-Magnesium detergent and/or severely limiting the concentration of Ca in the engine oil have recently been proposed as potential means to reduce LSPI. In this work, we evaluate the impact of detergent type on LSPI performance as well as on other performance that the modern engine oil needs to deliver. Particularly the impact of detergent type on Fuel Economy performance is evaluated. To ensure a rigorous and high precision measurement of the impact of engine oil on fuel economy, representative of real-world conditions, under well-controlled conditions, the ASTM D8114 test (Sequence VIE) was used to quantify fuel economy performance…

This paper details the light weight developments with the use of fracture mechanics technology. Forty percent weight reduction was achieved in an automotive axle. Novel pinion cartridge, ring gear , and differential designs were incorporated in this project to achieve weight, efficiency, noise and performance targets. A fracture mechanics (crack growth model) was used to determine steel cleanliness levels required as component size was optimized based on processing variables(steel material properties, initial flaw size, residual stress, duty cycle analysis,...). Prototype hypoid gear samples made from two variations of steel cleanliness were used to qualify the crack growth models with and without the addition of shot peening to vary the residual stress profiles for life requirements. Housing material variations of aluminum and magnesium were used for additional weight reduction in this program.

Investigation into fuel system warranty has led to the need to develop cost effective, robust materials that are resistant to both fuel and aggressive cleaners. Acetal (POM) is the current material that is used universally by OEM’s throughout the fuel system for its excellent performance in fuel and relatively low cost, but lacks resistance to strong acidic solutions. Acid containing wheel cleaning solutions are increasingly being used by customers to clean their aluminum and magnesium wheels. Due to the proximity of the fuel modules to the wheel openings, acidic wheel cleaners chemically attack the POM resulting in cracks. FCA worked closely with suppliers in recent years to develop cost effective, acid resistant POM materials that can withstand the stress-cracking at severe acid concentrations and meet FCA’s functional requirements. Other material alternatives that were considered outside of the acetal family provided adequate resistance but had other design and functional issues that would drive up cost. Our study included three unique vehicle flange designs molded in both types of POM and subjected to an extensive acid exposure…

Many modern engine platforms use turbochargers to meet higher fuel economy performance, which is often combined with downsizing the engine displacement. Operating downsized, turbocharged, direct injection engines at low speeds and high loads has led to an abnormal combustion phenomenon known as Low Speed Pre-Ignition (LSPI), wherein the fuel-air mixture ignites before the spark occurs. LSPI can lead to extremely high pressures in the combustion chamber, which can damage hardware such as pistons, piston rings, and spark plugs.Lubricants, fuels, and engine operating conditions have been shown to impact LSPI. Any of these can be modified to improve LSPI performance. One solution which has been used widely in the industry is reformulating the lubricant additive package. In particular, calcium-based detergents have been shown to promote LSPI, while magnesium detergents appear neutral to LSPI. Reducing the usage of calcium detergents can impact other performance areas such as deposit control and fuel economy, and limits formulating flexibility. Finding an additive solution to LSPI which does not require a reduction in calcium allows for more component options in formulating…

This specification covers aluminum and aluminum alloy foil in the form of laminated sheet.

This document is a guide to the application of magnesium alloys to aircraft interior components including but not limited to aircraft seats. It provides background information on magnesium, its alloys and readily available forms such as extrusions and plate. It also contains guidelines for “enabling technologies” for the application of magnesium to engineering solutions including: machining, joining, forming, cutting, surface treatment, flammability issues, and designing from aluminum to magnesium.

This specification covers an aluminum alloy in the form of sheet and plate 0.020 to 0.499 inch (0.51 to 12.67 mm) inclusive, in nominal thickness (see 8.4) alclad two sides.

A ceramic bound matrix has been investigated to be used as a friction material. The materials were produced by means of ceramic technology using frits containing silicates, and ceramic friction modifiers such as tin oxide, zircon, iron oxide, magnesium oxide. Four formulations were tested by means of a tribometer (pin-on-disc tester) using a gray cast iron counterpart. Test section included speeds between 1 and 12 ms-1, and loads between 25 and 400 N. The coefficient of friction of the tested specimens were between 0.7 and 0.4, and exhibited sensitivity to speed at low loads (25 N), while they are quite stables at high loads (400N). The characterization of the tribolayers was carried out by means of scanning electron microscopy. The four developed materials were named A, B, C, and D. They exhibited different wear rates and coefficients of friction. All the materials exhibited sensitivity to speed, while showed a lower sensitivity to load. The coefficient of friction level seems to be suitable for brake applications, oscillating between 0.6 and 0.4, depending on the test section.…

This specification covers an aluminum alloy in the form of Alclad sheet and plate 0.040 to 1.000 inch, incl (1.02 to 25.40 mm, incl) in nominal thickness (see 8.4).

This specification covers an aluminum alloy in the form of sheet and plate alclad two sides, over 0.187 to 1.000 inch (over 4.750 to 25.40 mm) in nominal thickness, supplied in the -T3/-T351 temper.