Abstract: A method and apparatus for analysis of engines analyzes digitized input signals from, for example, engine injectors and compares this digital data with the corresponding values of a digitized template or comparison signal. Compliance or divergence between the digitized signal values is indicated in bar graph form.

Abstract: A method and apparatus for analysis of particulate content of gases, applicable to the quantitative and qualitative analysis of vehicle engine emissions, includes sampling, removing particles and analysis of the removed particles. Sampling is effected by electrostatic precipitation using a catalyst-coated piezoelectric crystal. The analysis of the removed particles is effected by heating the crystal in an oxidizing atmosphere to oxidize the deposited particles. Connection of the crystal to an oscillation circuit enables the frequency of oscillation of the crystal to be monitored. Changes in the frequency of oscillation are interpreted to provide quantitative and qualitative analysis of particles deposited and subsequently oxidized.

Abstract: A method of analyzing exhaust gas emissions from an internal combustion engine is modified by the provision of a data process or connected to an exhaust gas analyzer and adapted to monitor changes in exhaust gas concentrations and to identify changes indicative of the state of operation of a catalytic system provided in the engine exhaust delivery system. The catalyst-on condition is identified by reference to the characteristic shape of the plot of the gas concentrations against time. Similar identification of catalyst-off conditions is provided by corresponding analysis of concentration changes and concentration values. The system can distinguish between various causes of the catalyst-off condition.

Abstract: A method and apparatus for instantaneously measuring the level of carbon dioxide (and other gases) in automotive combustion exhaust analysis is provided in the form of a portable battery driven roadside diagnostic instrument in which the CO.sub.2 level is measured by a calorimetric technique utilizing light as the energy source and a piezoelectric bimorph to vibrate a single fiber-optic element to multiplex between two fiber-optic receptors delivering the light to a measurement cell and a reference cell. The measurement cell comprises a salt of an acid-base indicator dye which provides proportional color change on contact with CO.sub.2. The dye is supported on a polymetric film in the cell.

Abstract: Gas analysis apparatus particularly applicable to the quantitative monitoring of individual gas components in automotive exhausts, and providing this function in a rapid-response and hand-held, low power consumption format, comprises an array of electrically responsive solid-state sensors to which the mixture of automotive gases to be analyzed is simultaneously fed. Monitoring the electrical response of the sensors enables a substantially instantaneous determination of the quantitative presence of individual components of the gas mixture.