Profound Insight
At Bosch, research and advanced development means always thinking a step ahead, setting the course today for the needs of the future. Future injection components, for instance, will predictably have to meet ever more exacting requirements.
Present-day common rail injectors for diesel engines operate at 1,600 bars of injection pressure. In the future this will be increased to 2,000 bars and even higher to make engines more fuel-efficient and environmentally compatible. But such high pressures require greater precision in component manufacture. Permissible tolerances will be smaller. Bosch researchers have already developed a testing method for this future requirement – an endoscope that can be advanced into the interior of the component to optically examine hidden surfaces.
The critical spots in new injectors will be located where the high pressures of 2,000 bars must be sealed off – at the valve seat, where the needle makes contact. The sealing surface must therefore be subject to especially tight production tolerances. Even the smallest deviations will interfere with the component’s function. Current production tolerances amount to less than one micrometer (millionth of a meter). But Bosch researchers have used statistical calculations to determine that the testing method will have to be 40 times more accurate – to within a few nanometers. An optical method known as white-light interferometry happens to be accurate to a few nanometers. A light beam is directed on the sealing surface and compared with a reference beam. The result is a precise surface profile.
A patent has been applied for, and the method was first presented to an audience of professionals at an international conference in July 2002.
The endoscope is inserted into the component and allows nondestructive measurement of important parameters. The first functioning prototype was built in the Bosch Research Department. The method will be used to test valve seats in step with the production cycle.
The critical spots in new injectors will be located where the high pressures of 2,000 bars must be sealed off – at the valve seat, where the needle makes contact. The sealing surface must therefore be subject to especially tight production tolerances. Even the smallest deviations will interfere with the component’s function. Current production tolerances amount to less than one micrometer (millionth of a meter). But Bosch researchers have used statistical calculations to determine that the testing method will have to be 40 times more accurate – to within a few nanometers. An optical method known as white-light interferometry happens to be accurate to a few nanometers. A light beam is directed on the sealing surface and compared with a reference beam. The result is a precise surface profile.
A patent has been applied for, and the method was first presented to an audience of professionals at an international conference in July 2002.
The endoscope is inserted into the component and allows nondestructive measurement of important parameters. The first functioning prototype was built in the Bosch Research Department. The method will be used to test valve seats in step with the production cycle.
