Common Rail Direct Injection: What You Need to Know

by / Wednesday, 14 May 2014 / Published in Automotive News

Common Rail Direct Injection

Being known as “the other fuel” isn’t easy on the dual reputation of diesel as both economical and “working class”, but it’s good to know that diesel engine technology has come through leaps and bounds over the last few decades. We share this information with you because, here at Roberts AIPMC, we believe that your car deserves the most durable metal parts it can get.

No longer is diesel about spewing thick black smoke across the freeway and making that familiar knocking noise along the way. Diesel is now known as a fuel-efficient way to get around that is encouraged for those who seek to get more miles out of their buck. This is due to the common rail direct injection.

A Little Background

Most people identify direct injection from gasoline engines, not in diesel, which uses internal combustion engines. Back in the day, diesel engines utilized mechanical indirect injection to introduce the fuel into the combustion, which was much less efficient than current methods.

The engine itself has been machined and built to precision and durability well above most standards. However, it still wasn’t enough to provide the high-working pressures to sustain the spray pattern of the fuel that’s required for it to attain the optimal fuel-air ratio and burn efficiently.

In these older mechanical indirect injection engines, the pump did two things: (1) supply fuel system pressure and (2) serve as a timing and delivery device as the pump pressure forces the mechanical injectors to open. Since there were no electronics back in the day to regulate these processes, the system relied on mechanical inputs like the fuel pump RPM and throttle position, which led to numerous variables that could cause certain damages in the long run.

The Thing about Diesel Engines

Aside from lack of electronic technology, there were also limitations in diesel technology itself back in those days. Things were easier with gasoline since spark plugs were easy enough to make the fuel mixture ignite. With internal combustion though, higher pressures and temperatures are required, which is why diesel was less efficient.

Additionally, diesel engines used to function poorly under cold temperatures, which was why diesel automobile users had to heat up their engines first before driving off, creating the necessity for glow plugs to supplement the heating process during cold conditions.

The Role of Common Rail Direct Injection

All of these maladies were solved with the introduction of electronic systems in diesel engines. That’s where we got the electronic common rail direct injection, which was a big step up for diesel technology. On top of the mechanical processes that circulated the fuel were small computers that tell the whole system exactly how much fuel needs to be used. Modern diesel engines have risen up in popularity and reputation as a clean and economical option because of this, making it a much more viable alternative to gasoline.

In the common rail system, the high-pressure fuel rail and the electronic injectors handles most of the job. No longer does the fuel pump need to double its duty since the computer takes care of the work. The fuel injectors are mounted above the piston in such a way that it can stand really high pressures necessary to ignite the fuel when injected.

Since the system relies much less on mechanical processes, the seal in the cylinders can be made to be more airtight so much higher pressures can be achieved. This made for a much more efficient diesel engine that could work in colder temperatures and other adverse conditions.

This system results in easier maintenance and more innovations as well as a cleaner and more fuel-efficient diesel engine that even the major automobile companies are lauding for. You can now buy a diesel-powered car from a major manufacturer and not be seen as a plebeian due to this major advance in diesel technology.

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