Octane Test Engine Unit-Octane Rating Operation Conditions

Octane cfr test engine/Sinpar octane rating unit provides the complete solutions for fuel octane testing, the unit is equipped with a crankcase with flywheel connected to main electrical motor, a cylinder sleeve assembly with variable adjustable compression ratio, a jacket coolant system, a four-bowl carburetor, an intake air system with controlled temperature and humidity equipment, electrical control system and a combustion knock measurement equipment.

Proper octane rating operation of the octane cfr test engine unit requires a series of adjustment and setting conditions according to ASTM D2699 and ASTM D2700:

Research Method (ASTM D2699)	Motor Method (ASTM D2700)
Engine Speed: 600 RPM +/- 1%	Engine Speed: 900 RPM +/- 1%
Spark Timing: 13° BTDC	Spark Timing: Variable Based on Cylinder Height
Intake Air Temperature: 52°C±1°C	Mixture Temperature: 149°C±1°C
Jacket Temperature: 100°C±1.5°C	Jacket Temperature: 100°C±1.5°C
Oil Temperature: 57°C±8.5°C	Oil Temperature: 57°C±8.5°C
Oil Pressure: 172-207 kPa	Oil Pressure: 172-207 kPa
Intake Air Humidity: 25-50 grains of moisture/lb. of dry air	Intake Air Humidity: 25-50 grains of moisture/lb. of dry air

NOTE about intake air temperatures：

If Intake Air Temperature tuning is used to qualify the octane engine as fit-for-use, the temperature can be adjusted within ±22°C from the base temperature specified for the prevailing barometric pressure, and this temperature shall then be maintained within ±1°C, when the Compression Ratio or Knock Intensity readings results used for octane determination on each fuel are recorded. See ASTM D2699 for details.
If Intake Mixture Temperature tuning is used to qualify the octane engine as fit-for-use, the temperature can be adjusted between 141°C-163°C, and this temperature shall then be maintained within ±1°C, when the Compression Ratio or Knock Intensity readings results used for octane determination on each fuel are recorded. See ASTM D2700 for details.

In addition to the above main operation conditions, the following basic adjustments or settings shall be performed before the rating operation of cfr test engine:

Belt tension adjustable;

Basic rocker arm carrier adjustment;

Basic cylinder height setting (For more details, please see “How to Reset Cylinder Height” in our blog.);

Knock meter adjustable;

Cylinder jacket coolant level and octane engine crankcase lubricating oil level adjustable.