About
In order to improve the optimisation of the valve timing for differing engine speeds and loads, the system is able to vary the timing and duration of the inlet valve opening. It achieves this by using a complex and finely machined mechanism to drive the inlet camshafts. This mechanism can accelerate and decelerate the rotational speed of the camshaft during different parts of its cycle. e.g. to produce longer opening duration, it slows the rotation during the valve open part of the cycle and speeds it up during the valve closed period.
The system has the advantage that it is continuously variable rather than switching in at a set speed. Its disadvantage lies in its complexity. Other systems achieve similar results with less expense and better reliability.
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A poppet valve is a valve typically used to control the timing and quantity of gas or vapour flow into an engine.
A camshaft is a shaft to which a cam is fastened or of which a cam forms an integral part.
The Rover K-series engine is a series of engines built by Powertrain Ltd, a sister company of MG Rover. The engine was built in two forms: a straight-four cylinder, available with SOHC and DOHC, ranging from 1.1 to 1.8 L; 68.3 to 109.6 cu in.
VTEC is a system developed by Honda to improve the volumetric efficiency of a four-stroke internal combustion engine, resulting in higher performance at high RPM, and lower fuel consumption at low RPM. The VTEC system uses two camshaft profiles and hydraulically selects between profiles. It was invented by Honda engineer Ikuo Kajitani. It is distinctly different from standard VVT systems which change only the valve timings and do not change the camshaft profile or valve lift in any way.
VVT-i, or Variable Valve Timing with intelligence, is an automobile variable valve timing technology developed by Toyota. The Toyota VVT-i system replaces the Toyota VVT offered starting in 1991 on the 5-valve per cylinder 4A-GE engine. The VVT system is a 2-stage hydraulically controlled cam phasing system.
VANOS is a variable valve timing system used by BMW on various automotive petrol engines since 1992. The name is an abbreviation of the German words for variable camshaft timing: variable nockenwellensteuerung.
MIVEC is the brand name of a variable valve timing (VVT) engine technology developed by Mitsubishi Motors. MIVEC, as with other similar systems, varies the timing of the intake and exhaust camshafts which increases the power and torque output over a broad engine speed range while also being able to help spool a turbocharger more quickly and accurately.
In automotive engineering, an inlet manifold or intake manifold is the part of an engine that supplies the fuel/air mixture to the cylinders. The word manifold comes from the Old English word manigfeald and refers to the multiplying of one (pipe) into many.
Alfa Romeo Twin Spark (TS) technology was used for the first time in the Alfa Romeo Grand Prix car in 1914. In the early 1960s it was used in their race cars to enable it to achieve a higher power output from its engines. And in the early and middle 1980s, Alfa Romeo incorporated this technology into their road cars to enhance their performance and to comply with stricter emission controls.
Nissan Variable Timing control or Nissan Valve Timing Control System is an automobile variable valve timing technology developed by Nissan. N-VTC was first introduced in 1987 on the VG30DE and VG20DET engine.
In a piston engine, the valve timing is the precise timing of the opening and closing of the valves. In an internal combustion engine those are usually poppet valves and in a steam engine they are usually slide valves or piston valves.
The KV6 automotive petrol engine has a 24-valve quad-cam V6 configuration, and a pressurising variable-length intake manifold to add hot spots throughout the rev range. Variants exist in 2.0 to 2.5 litres capacities. These were built initially by Rover Group, then by Powertrain Ltd. KIA manufactured KV6 in Korea under licence. Production moved from the UK to China in 2005, re-designated NV6.
The Rover 200 Coupé is a two door coupé that was produced by Rover and based on the Rover 200 Mark II, with most of the body panels and the bumpers unique in the range. The car was launched on 6 October 1992, at the Paris Motor Show. It was given the project code name 'Tomcat' when in development.
The uniflow type of steam engine uses steam that flows in one direction only in each half of the cylinder. Thermal efficiency is increased in the compound and multiple expansion types of steam engine by separating expansion into steps in separate cylinders; in the uniflow design, thermal efficiency is achieved by having a temperature gradient along the cylinder. Steam always enters at the hot ends of the cylinder and exhausts through ports at the cooler centre. By this means, the relative heating and cooling of the cylinder walls is reduced.
A helical camshaft is a type of mechanical variable valve actuation (VVA) system. More specifically it is a camshaft that allows the valve opening duration to be varied over a wide, continuous, step-less range, with all of the added duration being at full valve lift.
MultiAir is a hydraulically-actuated variable valve timing and variable valve lift engine technology enabling "cylinder by cylinder, stroke by stroke" control of intake air directly via a gasoline engine's inlet valves. Developed by Fiat Powertrain Technologies, the technology bypasses a primary engine inefficiency: pumping losses caused by restriction of the intake passage by the throttle plate, used to regulate air feeding the cylinders.
Variable valve timing (VVT) is a system for varying the valve opening of an internal combustion engine. This allows the engine to deliver high power, but also to work tractably and efficiently at low power. There are many systems for VVT, which involve changing either the relative timing, duration or opening of the engine's inlet and exhaust valves.
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. Continuous valve lift systems typically allow for the elimination of the throttle valve.
The Modular Engine Management System, or MEMS, is an electronic control system used on engines in passenger cars built by Rover Group in the 1990s. As its name implies, it was adaptable for a variety of engine management demands, including electronically controlled carburetion as well as single- and multi-point fuel injection The abbreviations "SPi" and "MPi" refer to the single-point and multi-point injection configurations, respectively.
