Abstract: A test stand for testing multiple engines which may be liquid cooled or air cooled including apparatus for preheating a liquid coolant to preheat the engine prior to testing, apparatus for heating lubricant for preheating the engine prior to testing, apparatus for conserving the heat through heat exchangers to heat the coolant and the lubricant for a supply of coolant and lubricant for testing a successive engine; a brake and drag for the engine arranged for generating electricity to obtain electrical energy from the testing forces. For an air cooled engine, a throttle arrangement is added to block the air for a fast heating of the engine prior to testing. In one form, lubricant is bypassed from the sump up to the head of the engine and heated in the bypass such as by a heat exchanger energized by heat from the coolant from testing a previous engine.

Abstract: A measuring instrument and a method of measuring including providing an illumination arrangement having a plurality of independent illumination sources, a specimen region for conducting a specimen illuminated by the illumination arrangement, a measuring arrangement detecting radiation influenced by the specimen in the specimen region, the illumination arrangement having a plurality of independent aluminum sources which are energized by separate leads and separate switch elements that are operable to selectively operate either individually or in common for a linearity check.

Abstract: The invention relates to a plate orifice for a or in a measuring device for he flow metering of fluid streams, in particular gas streams, preferably for gas streams present in internal combustion engines, with the fluids, in particular the gases, being guided through at least one plate orifice (restrictor) disposed in a pipe and provided with a sharp edge definig its flow orifice, with a pressure sensor or a pressure measuring line of a differential pressure measuring device or of a differential pressure transducer disposed upstream as well as downstream of the plate orifice, the output signal of the differential pressure measuring device or the differential pressure transducer depending on the differential pressure forming the measuring signal for the fluid flow rate, in particular gas flow rate, through the plate orifice and optionally being fed to an evaluation unit. In plate orifices or measuring devices of this type, problems due to their contamination and their universal usability arise.

Abstract: A method and apparatus for controlling the volume stream of a sub-quantity which is continuously removed from a gas stream and which is supplied and mixed with a gaseous dilutant stream, the sub-quantity is conducted from the main stream through a back-up region where the control of the flow of sub-quantity without affecting its composition is effected by a counterflow in a back-up region which is controllably directed in opposition to the sub-quantity flow such as by an annular upstream directed gap surrounding the sub-quantity conduit or by openings which are directed in a direction against the sub-quantity flow or by a pipe directing a flow against the discharge end of the sub-quantity flow. The sub-quantity flow is mixed in a mixing tunnel with a dilution gas and a small quantity of this mixed gas is removed for testing.