Engine calibration tools are software and hardware that record data from an engine under test and adjust the engine's settings. They are used by the engineers who develop engines. Calibration means choosing the best values for these settings.
An engine's computer, its electronic control unit, does not work out everything from scratch. It looks up stored tables. For example, one table says how much fuel to inject at each engine speed and load. A calibration engineer fills in these tables. The engine must give power, use little fuel and produce few harmful gases, all at the same time. In India, the limits on these gases are set by the Bharat Stage VI (BS6) norms.
The engineer puts the engine on a test bench, where it runs under controlled conditions. The calibration tool connects to the engine's control unit. It records hundreds of values many times every second, such as the speed, the temperature, the air flow and the exhaust gases. The engineer changes a value in a table, runs the engine again and sees what happens.
Here is a typical case. A calibration team in Pune is preparing a petrol engine for cold starts. On a winter morning in Srinagar, the air is near freezing and the fuel does not vaporise easily. So the engine needs more fuel for the first few seconds. The team places the engine in a cold test room. They adjust the cold-start tables until the engine starts at once and the exhaust stays within the limit.
Each new engine and each new market needs its own calibration. The same engine in a hot country and a cold country can use different tables.
The result is then copied to the real control unit that goes into cars. Before the car goes on sale, a testing agency approved by the government, such as the Automotive Research Association of India in Pune, checks it against the emission norms. This work is part of building the powertrain. Calibration tools often work with model-based design, where engineers test a model of the engine in a computer before testing the real one. Safety rules still apply, as described under safety certification.