Choosing Between Frequencies: 28 kHz vs 40 kHz for Ultrasonic Engine Cleaning

When selecting a stainless steel ultrasonic engine cleaner / DPF filter cleaning machine with pump, one of the most important technical decisions is frequency selection. Many machines offer settings such as 28 kHz or 40 kHz. Understanding the difference helps you match the machine to your cleaning needs.

What does frequency mean in ultrasonic cleaning?
The frequency refers to the number of sound wave cycles per second. Lower frequencies yield larger cavitation bubbles which collapse with greater energy and produce stronger mechanical impact. Higher frequencies create smaller bubbles with less aggressive force but finer cleaning resolution.

When to use 28 kHz

• For heavily soiled parts such as engine blocks with thick carbon build up, DPF filters with baked soot, turbo components with heavy deposits.

• When mechanical impact is needed to dislodge heavy grease, oil, carbon, rust or welding spatter.

• When parts are rugged and durable, and don’t have extremely delicate surfaces.
  The result is faster and deeper cleaning of tough contamination.

When to use 40 kHz

• For parts with more delicate features: thin-walled castings, internal fins, fine passages, or coated surfaces.

• For removing light contamination, fine particles, polishing buff residues or wearable engine parts that must maintain surface integrity.

• When you prefer gentler cleaning action to avoid surface pitting or damage.
  A cleaner result with minimal risk of substrate damage.

Hybrid or dual-frequency machines
Many modern ultrasonic cleaners for engine and filter cleaning offer both frequency options (28 kHz and 40 kHz) so you can switch depending on part and contamination type. This versatility allows one machine to handle a wide range of cleaning tasks.

Other related parameters
Beyond frequency you must consider power (for example 3600 W), tank size, temperature, chemical solution, and pump/filtration system. Lower frequency with insufficient power or inadequate fluid flow may deliver sub-optimal cleaning. Likewise higher frequency alone cannot compensate for poor fluid quality or incorrect solution.

Practical decision-points

• Review your typical workload: if you primarily clean heavy carbon/soot and big engine parts then 28 kHz is essential. If you also clean precision components then 40 kHz (or dual-frequency) is smarter.

• Consider part geometry: complex shapes, fine passages or thin walls favour higher frequency for gentler cleaning.

• Consider throughput: rugged parts with heavy loads benefit from lower frequency and higher power for speed.

• Ensure your machine allows frequency selection and consult manufacturer for optimal settings and cycle times.

In conclusion, frequency is a key specification for ultrasonic cleaning machines targeted at engine parts and DPF filters. Choosing 28 kHz for heavy soiling and 40 kHz for finer cleaning gives you the best of both worlds. A stainless steel ultrasonic engine cleaner with pump that supports both frequencies is highly flexible and future-proof.