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Variable valve lift (VVL) is an automotive piston engine technology which varies the height a valve opens in order to improve performance, fuel economy or emissions. There are two main types of VVL: discrete, which employs fixed valve lift amounts, and continuous, which is able to vary the amount of lift.
It allows a V6 or V8 engine to "turn off" half of the cylinders under light-load conditions to improve fuel economy. Estimated performance on EPA tests shows a 5.5–7.5% improvement in fuel economy. [1] GM's Active Fuel Management [2] technology used a solenoid to deactivate the lifters on selected cylinders of a pushrod V-layout engine.
These may improve fuel economy because the engine runs slightly lean as a consequence. However, running leaner than the manufacturer intended can cause overheating, piston damage, loss of maximum power and poor emissions (e.g., higher NOx due to higher combustion temperatures, or, if misfiring occurs, greater hydrocarbon emissions).
A typical ETC system consists of three major components: (i) an accelerator pedal module (ideally with two or more independent sensors), (ii) a throttle valve that can be opened and closed by an electric motor (sometimes referred to as an electric or electronic throttle body (ETB)), and (iii) a powertrain or engine control module (PCM or ECM). [4]
If no communication is exchanged with the client for a long time, the control unit automatically exits the current session and returns to the "Default Session" back, and might go to sleep mode. Therefore, there is an extra service which purpose is to signal to the device that the client is still present.
The new global family is designed to improve fuel economy, performance, and emissions, while reducing noise and vibrations. To achieve this, it features a lightweight design and advanced technologies like gasoline direct injection , turbocharging , variable-length intake manifolds , and alternative fuel compatibility.
Arvin Meritor, a Tier 1 supplier of automotive technology, at one time, was experimenting with a plasma reformer technology which would use hydrogen produced from the fuel to enhance engine combustion efficiency and reduce emissions of NO x. [26] This reference states that a 20% to 30% increase in engine thermal efficiency is possible. However ...
A full authority digital engine (or electronics) control (FADEC) is a system consisting of a digital computer, called an "electronic engine controller" (EEC) or "engine control unit" (ECU), and its related accessories that control all aspects of aircraft engine performance.