Direct injection is generally used in case of internal combustion engines. These engines are basically adopted in the modern 2 stroke engines as well as 4 stroke engines. In these engines, the gasoline is pressurized first and then it is injected into a combustion chamber with the help of a fuel line. This technology is different from the conventional technology, and this does not involve the multipoint fuel injection that happens in the cylinder port or intake tract.
There are many advantages of using a direct injection outboard motor engine. High power output and increased fuel efficiency are among the two biggest advantages of these engines. In addition to it, the injected fuel leads to the cooling effect and evenly dispersed mixture allow for far more aggressive ignition timing. If you have direct injection outboard motor with you then you can control the levels of emission or pollution. This happens mainly because of more precise control of the fuel as well as injection timings that are varied according to the condition of load.
In these engines the engine speed is usually controlled by engine management system or EMS, as it is popularly known. It regulates the ignition timing and fuel injection function, instead of having a throttle plate that restricts the supply of air. Apart from this function, the engine management system requires enhancement of memory and processing so as to ensure good drivability and performance. Unlike the carbureted or fuel injected engines, there are hardly any throttling losses in some direct engines, thereby reducing the pumping losses, improving efficiency in engine.
The concept of hybrid technology has made direct injection outboard motors even more popular. Now you can find direct injection accompanied with various other technology like Water Injection, Variable Valve Timing and Ultra Lean Mixtures etc.
These technologies have made it possible to inject the fuel in multiple times during a single cycle, thereby resulting in more economy and power. Due to this reason, most of the companies are switching to this technology in their normal running.
Now with almost all the major outboard engines manufacturers making use of these technologies and coming out with a wide range of direct injection motors you will face a tough time in choosing one. All you need to do is to gather as much information as possible and then make a wise and logical decision. Don’t get away with the lucrative ads that you see but check on the specification of the engines so as to see which of them cater to your needs.
Direct injection motors are more appropriate in case of 2 stroke engines, simply because they want to eliminate the pollution emission levels. In 2 stroke engines, the intake ports and exhaust both are opened at the same time, thus a large portion of unburned fuel get out of exhaust port. However with direct injection only air comes out of the crankcase, resulting in reduced emission.