D. López

Advanced Hypersonic Flamespray Coatings for Cylinder Liners in Light Metal Engines

The reduction of fuel consumption and pollution emissions, the improvement of the engine efficiency as well as the cost reduction in manufacturing and assembly are in the focus of actual research activities in the automotive industry. Most of these requirements can be fulfilled by a reduction of the total vehicle weight. This results in an increasing utilization of light metals for chassis, body and engine components. Significant weight savings are obtained by changing the engine block material from cast iron to aluminum. Due to the harsh operation conditions, the aluminum cylinder must be reinforced. Approaches to increase combustion as well as operation efficiency and lifetime of light metal engines are thermally sprayed APS (Atmospheric Plasma Spraying) and HVOF (High Velocity Oxygen Fuel Spraying) coatings on cylinder liners of the aluminum crankcases. By using this coating technologies, also material combinations containing solid lubricant dispersions can be deposited. The thermal spray processes represent a cost effective and flexible solution for the engine technology. Meanwhile, APS coatings for 4-cylinder engine blocks are produced in series production. Actual research activities are focused on the development of advanced HVOF sprayed coating systems on cylinder liners, the coating optimization and the cost effective implementation of this technology in an automated series production process. In hypersonic flame spraying (HVOF), the coating is deposited by an elliptically moving HVOF gun, whereas the cylinder liner is rotating. By HVOF processing an improved coating microstructure (less porosity) and superior coating adhesion is obtained. The HVOF coatings are homogeneous, with a dense, bulk like microstructure, a low porosity (« 5%) and surface roughness as well as a superior coating adhesion compared to APS coatings.

Advanced Robot Assisted Manufacturing and Control System for the Internal HVOF Series Coating Process of Cylinder Bores in Light Weight Engine Manufacturing

Actual necessities in the automotive industry are the reduction of fuel consumption and pollution emissions, engine efficiency improvement, as well as cost reduction in manufacturing. Light weight engineering in the powertrain and especially in the motor engineering is a key to fulfill most of these requirements. A very promising technology is the reinforcement of the inner surface of cylinder liners in aluminum crankcases using thermally sprayed coatings. In order to achieve a cost effective, reliable and flexible solution for series production, as well as the maintenance of high quality standards, an interdisciplinary cooperation between material science and robot assisted engineering and manufacturing technology has to take place.

Ceramic and Cermet Coatings for Cylinder Liner in Ultra Light Weight Engines - Novel Processing and Manufacturing of Ceramic Layer Composites

Actual requirements in the automotive industry are the reduction of fuel consumption and pollution emission, engine efficiency improvement, as well as cost reduction. Most of these requirements are fulfilled by reducing the total weight of the vehicle. This results in an increasing utilization of light metal components for engine applications. Significant weight savings are obtained by changing the engine block material from cast iron to aluminum or even to magnesium aluminum hybrid constructions. Despite of all advantages the industrial implementation of light metals is often inhibited by their poor surface properties especially concerning wear and tribological behavior. Due to the highly loaded operation conditions a cylinder liner surface reinforcement is necessary. A very promising technological alternative is the internal cylinder reinforcement by using HVOF (high velocity oxygen fuel) sprayed coatings. By using these advanced high energetic coating technologies, material combinations containing solid lubricant ceramic dispersions can be deposited. The thermal spray processes represent a cost effective and flexible solution for ultra light weight engine technology. This research is focused on the development of HVOF sprayed coating systems for cylinder liners, the coating optimization and the cost effective implementation of this hypersonic spray technology in a series production process. It will be shown that cast engine block bores can be directly coated by using an automated HVOF process, obtaining improved coating results. The internal coating process by hypersonic flame spraying is a superior technological alternative to the APS process for high quality cylinder liner and engine crankcase applications.