Internal combustion engines need clean air to work properly; otherwise, power and efficiency quickly decline. But some work environments are filled with airborne debris and dust. How does your engine’s air intake system remove impurities for optimum engine performance and longevity?
One-stage Air Cleaners for Diesel Engines
Of course, filtering the air is the best way to clean it. One-stage air cleaners allow incoming air to pass directly through the main filter. They are effective in environments with little air contamination.
Two-stage Air Cleaners for Diesel Engines
A two-stage air cleaner is a better choice in the dustier environments of the ag and construction fields. A two-stage cleaner is a pre-cleaner and filter in one. The pre-cleaning process removes larger contaminants from the incoming air and the filter captures the finer particles. This is usually accomplished with centrifugal force. Air is forced to rotate in the pre-cleaner unit, and heavy dirt particles are thrown out of the rotating column of air. The removed dirt is ejected from the pre-cleaner or collected in a vacuator tube. A pre-cleaner increases the longevity of the air filter and prevents engine damage by removing 75-98% of incoming airborne contaminants.
If a two-stage air cleaner has a vacuator tube, the outlet is capped with a vacuator valve (or just a vac valve for short). When the engine is under load, the vacuum in the two-stage air cleaner increases and sucks the vac valve shut. This creates a more efficient pre-cleaning process and allows heavier dirt to collect in the vacuator tube. When the engine is idle or shut off, the vacuum in the air cleaner decreases, the vac valve opens, and the dirt collected in the vacuator tube falls out.
Monitor the condition of the vac valve. It is a simple, wedge-shaped device that can be overlooked in routine maintenance checks. It is made of rubber and can become aged, cracked, or torn. If the valve is damaged or missing, replace it immediately. Otherwise, outside air contaminants will be sucked into the air cleaner and significantly reduce its ability to pre-clean the air. This will result in shorter filter replacement intervals and unscheduled downtime.
Diesel Engine Air Filters
Pay attention to the filter in your air cleaner. It should trap fine contaminants but allow an optimum amount of clean airflow to the engine. And when it comes to keeping your engine clean, a quality air filter matters. Don’t let numbers fool you. A filter with 99.999% efficiency allows 0.01 grams of dust to pass through for every 1000 grams of air filtered. You might be tempted to think, “That’s great! So a cheaper filter that’s 99% efficient should still do really well.” Even though you are decreasing a mere 1% efficiency, that cheaper filter will allow 100 times more dust to get into your engine.
How do you know when an air filter needs replaced? Don’t depend only on a visual inspection because an air filter that appears rather dirty can still have a useful life. Replacing filters too often wastes time and increases cost. Additionally, you run the risk of dust entering the system every time you pull an air filter to inspect it. To reduce this risk and maximize the service life of your air filter, use a filter service indicator mounted on the outlet side of the air cleaner to measure the airflow restriction. Many indicators have a “red zone” on them showing that the filter should be replaced when the airflow restriction reaches that limit. Keep in mind that engine manufacturers set allowable restriction limits, and you should contact the manufacturer if you do not know what the limit is. Also, indicators are made for varying restriction limits. Buy an indicator that aligns with the allowable restriction limit of the engine you are using. Other helpful monitoring tools include switches that turn on filter change warning lights and sensors that connect with your electronic devices, allowing you to observe your filter status in real time.
Diesel Engine Air Intake System Problems
What problems can your diesel engine encounter if the air intake system is compromised?
- Decreased performance – A dirty air filter restricts the airflow into the engine and compromises the engine’s performance. Engine power will decrease as dust and debris continue to accumulate on the filter.
- Engine noise – When your engine is running, you should hear the smooth vibrations of a healthy engine. Any odd popping, sputtering, or coughing noises could be a symptom of an air intake problem.
- Decreased fuel economy – Engines consume more fuel to maintain power if there is insufficient airflow.
- Black smoke – This is a symptom of an insufficient air supply. A fuel-rich mixture will not burn completely and will leave the engine as soot, producing black smoke.
To maximize your diesel engine’s performance, keep the air intake system clean and well-maintained.