D4ST refers to a turbocharged engine with direct injection and manifold injection modes, representing the engine Toyota 2.0L 8AR-FTE engine.
1.D4ST meaning
D4 represents the in-cylinder injection four-stroke engine, S represents “Superior version” upgrade. 1996 Toyota developed a direct injection fuel systems, integrated with manifold injector technology based on code D4.2005年在 D4, D4S developed a system with manifold injection cylinder injector combination, and mounted on the Lexus GS350 models, so D4S can be understood as a four-stroke direct injection engine upgrade. The D4ST is the use of four-stroke direct injection engine is an upgraded version of turbocharging technology, T refers to the turbocharger, the first equipped with the engine models is Lexus NX.
2.D4S Principle
D4S dual mode fuel injection. And other manufacturers are not the same pure direct injection, D4S uses direct injection and manifold injector design combining the two modes. Cold start and low load conditions, the mixing manifold injector can be even more fully, and the airway can be cleaned to avoid airway valve and coke deposition stolen goods. Under moderate load cylinder injection began to intervene, it is the only heavy-duty cylinder direct injection system at work. Two fuel injection system that combines the advantages of manifold injector and in-cylinder direct injection.
3.D4ST twin-scroll turbocharging system
single turbo single scroll, it is very simple to drive a turbine, is all cylinder exhaust pipe brought together, to assemble the exhaust gas. Ignition, four-cylinder engine the exhaust gas is generally the order 1-3-4-2 cylinder, the ignition of two cylinders (1, 3 cylinder) spaced adjacent, if the exhaust pipe communicating the exhaust gas interference easy to produce, it is easy to reduce the effect of the turbocharger, turbo lag such as more obvious, the movableTo increase, it will also be affected.
in order to solve or mitigate these problems, technology D4ST 4 → 2 using engine exhaust manifold and the cylinder head are integrally dual turbocharger technology. As the name suggests, it is increased as compared to a single scroll exhaust gas passage, forming a double-scroll. In view of the ignition interval between adjacent two cylinders easy to produce exhaust gas interference, it manifold 4 into the cylinders 2, 3, 4 and the two groups. When the cylinder 4 turns the exhaust gas, discharging the exhaust gas turns two scrolls, effectively cut off from the interference between the exhaust gas so that the exhaust gas smoother, more sensitive intervention turbo supercharger better.
