Σε ποιον δεν αρέσουν οι εισαγωγές στο καπό; Μάλλον κάπως έτσι σκέφτηκε η Chevrolet, που τοποθέτησε μία πατενταρισμένη εισαγωγή στο καπό του 2017 Silverado HD με τον 6.6 λίτρων Duramax turbo-diesel. Σύμφωνα με την εταιρία, η εισαγωγή αυτή όχι μόνο βοηθά στην ψύξη του κινητήρα, αλλά δημιουργεί και ένα πραγματικό “ram-air effect” που αυξάνει την απόδοση του.
Πώς λειτουργεί όμως και γιατί αξίζει να προστατεύεται από πατέντα; Η Chevrolet λέει ότι αφού ο αέρας περάσει από το άνοιγμα στο καπό, μπαίνει σε έναν θάλαμο διαστολής και κάνει στροφή 180ο πριν φτάσει στην εισαγωγή του κινητήρα. Στην στροφή αυτή, η ταχύτητα του αέρα αυξάνεται και τα μόρια του νερού που βρίσκονται μέσα σε αυτόν “ξεχωρίζουν” χάρη στη φυγόκεντρο δύναμη. Στη συνέχεια, το νερό συλλέγεται και αδειάζει μέσω μίας βαλβίδας, αφήνοντας τον αέρα ξερό –ή τουλάχιστον ξερότερο-, ελαχιστοποιώντας ένα από τα μειονεκτήματα τροφοδοσίας του κινητήρα με αέρα από την ατμόσφαιρα.
Η εταιρία ισχυρίζεται ότι περίπου το 60% του αέρα που καταλήγει στον κινητήρα προέρχεται από την εισαγωγή, εξασφαλίζοντας ότι αν αυτή μπλοκαριστεί για οποιονδήποτε λόγο, δεν θα στερηθεί το απαραίτητο οξυγόνο η μηχανή. Ωστόσο δεν παρέχει κάποιο συγκεκριμένο νούμερο όσον αφορά στην αύξηση της απόδοσης λόγω του ram-air.
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All-new Intake System Feeds Duramax Diesel on 2017 Silverado HD
Cool, dry air delivers lower engine temperatures, maximum performance
DETROIT – New for 2017, Chevrolet Silverado HD trucks feature a patented air intake system, which drives cool, dry air into the engine for sustained performance and cooler engine temperatures during difficult driving conditions. The intake system underwent extensive testing based on the most challenging real-world driving conditions to ensure capable performance no matter the weather.
Marked by a dramatic hood scoop, the all-new, air intake system provides 60 percent of the air to the Duramax diesel engine from an inlet at the front of the hood. This provides air to the engine that is very close to outside ambient temperature and much cooler than the air under the hood.
Cooler air helps the engine run better under load – especially in conditions where engine and transmission temperatures can rise quickly. Running cooler allows the Duramax diesel to maintain full power and vehicle speed for capable trailering in even the toughest conditions.
There’s also a ram-air effect from the incoming air at highway speed, which helps pack more air into the engine. The air filter housing also draws 40 percent additional air from a dry location in one of the front fenders. It blends with the cooler air from the hood inlet before funneling into the Duramax’s combustion chambers. This assures the engine can breathe even if the hood is completely blocked.
“The 2017 Silverado HD was engineered to provide maximum utility for our customers in even the most extreme situations,” said Eric Stanczak, chief engineer, Silverado HD. “While developing this all-new induction system, we considered our customers towing a maximum-weight trailer through the Eisenhower Tunnel on a hot, rainy summer day.”
At more than 11,000 feet, the Eisenhower Tunnel is the highest vehicle tunnel in the world and one of the highest elevations for any roadway in North America. Maximized engine performance requires more than cool air; the air must be clean and dry for optimum performance.
Accordingly, the functional hood scoop includes a unique air/water separator to ensure only combustion-enhancing dry air is drawn into the engine. The air charge enters an expansion chamber containing a sharp, 180-degree turn on its way to the air filter housing. That creates a velocity change that causes humidity or mist to form larger, heavier droplets that are flung centrifugally against the outside wall of the housing. The collected water drains through a valve, while the air charge continues on to the filter housing and into the engine.
Testing the effectiveness of the system was rooted in real-world driving conditions of every degree – from misty rains to monsoon-level downpours; from powder snow to wind driven ice pellets; from desert dust to arctic cold.
Surprisingly, torrential downpours do not necessarily pose the biggest challenge, according to Kevin Dunn, global vehicle performance for splash engineering: “Big, heavy raindrops from a thunderstorm are relatively easy to eliminate from air. The more challenging issue comes from the mist-like spray generated by semi-trucks on wet highways. Those very fine water droplets prove more challenging to separate from the air. The air intake is an elegant solution that works well with water droplets of all sizes. For customers, the results delivers maximum engine performance and even greater towing confidence.”
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