You’ve probably wondered how to quiet direct injection engines. You’ve heard of the ‘water hammer effect’ – that sonic boom you get when you turn off a water faucet too quickly, but it’s much worse and occurs over a shorter time. In order to eliminate this effect, DI engines must have stronger solenoids controlling fuel flow. While this makes them noisier, GM engineers took extra steps to quiet their engines and make them more quiet.
Intro
Fuel-injection engines have become the latest technological marvel in engine technology. Direct-injection technology has many benefits, from increased fuel efficiency to reduced noise levels. The advantages of DI outweigh the disadvantages, and many vehicles now use the technology. The technology is particularly advantageous in light commercial vehicles, where noise from acceleration can be a significant concern. Here’s a closer look at how DI works. This article will explain why it’s so popular in passenger cars and light commercial vehicles.
Types
There are two main types of fuel injection: indirect and direct. Direct injection uses a pump to inject fuel directly into the combustion chamber, bypassing the intake valve and the manifold. They are less expensive to manufacture and are less likely to be affected by fuel contamination. However, they are less efficient, produce more emissions, and are noisier than direct injection systems. Indirect injection is also easier to maintain and quieter than direct injection.
The injectors are controlled by a camshaft and usually emit a truncated cone pattern. Unit injector systems are typically used in medium-sized engines, such as those in trucks and buses. Common rail injection systems use a central injector that is connected to each cylinder through a high-pressure fuel line. Common rail systems typically use an electronic control unit to monitor fuel consumption and emissions. Both types are capable of delivering large amounts of fuel to each cylinder.
Cost
While direct injection engines are typically seen on luxury and higher-trim vehicles, they are increasingly being installed in mainstream cars. While the cost of direct injection is high, they may soon be affordable for more drivers. As with any new technology, there are a few drawbacks to direct injection engines. One such issue is reliability, which automakers are trying to keep quiet. For example, a VW shop has reported that they cleaned valves with walnut shells. The BMW shop also uses walnut shells for valve cleaning.
A DI system requires higher fuel pressure than a PI system, resulting in increased costs. The higher fuel pressure also imposes parasitic losses. Direct injection systems are also generally noisy, and carbon deposits can form on the intake valves and tailpipes. The fuel also escapes as soot and particulate matter, similar to the emissions from a diesel engine. But the cost is well worth it. And with so much to gain in performance, you should consider the cost of quiet direct injection.
Installation
Performance DI, or direct injection, is a relatively new market segment. Few tuners are familiar with this technology, so they need to prove its value and performance. Injection systems for performance vehicles offer a 15% gain in fuel economy and 50% more low-end torque. Yamaha has created a high-pressure direct injection system that is used on seven all-new motorcycles. The company also claims the system will boost fuel efficiency and decrease emissions.
