CFR Engines Inc. Octane Rating Unit

Combination Research & Motor Method

Model: F1/F2

The CFR F1/F2 Combination Rating Unit is the globally accepted standard for determining and certifying the anti-knock characteristics of motor fuels. The F1/F2 unit can run both the Research Method (RON) and Motor Method (MON) test, with testing capabilities in the 40-120 octane number range.

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ASTM D2699: Standard Test Method for Research Octane Number of Spark-Ignition Engine Fuel
ASTM D2700: Standard Test Method for Motor Octane Number of Spark-Ignition Engine Fuel
IP 236: Determination of Knock Characteristics of Motor and Aviation Fuels - Motor Method
IP 237: Determination of Knock Characteristics of Motor Fuels - Research Method

Key Design Features

Variable Compression Ratio Cylinder and Sleeve Assembly

At the heart of the CFR engine lies the variable compression cylinder and sleeve assembly by which the knock characteristics of unknown fuels can be determined. Varying the compression ratio by manipulating the cylinder height during engine operation produces various levels of knock intensity, making it possible to compare unknown fuels to reference fuels with known octane values. Cylinder height is correlated to a compression ratio which can then be directly correlated to a specific octane value as per ASTM method specifications. A laser height sensor mounted on the cylinder/sleeve exterior assists the operator in determining the cylinder position as it is raised or lowered. The available compression range is 4:1 to 18:1, which allows for testing a wide range of fuels.



Four-Bowl Falling Level Carburetor

The CFR Octane Rating Unit is equipped with a four-bowl variable-level carburetor that includes a falling level mode. This mode enables finer and more sensitive fuel flow adjustments that result in more accurate fuel ratings. The CFR’s falling level carburetor gives the operator the flexibility to utilize any of the four test procedures in ASTM Methods D2699 and D2700.


When used with the XCP control panel’s falling level program, the operator can perform an efficient and accurate falling level test that determines maximum knock intensity without requiring manual adjustment of the carburetor bowl. With the falling level program, a single operator can run very accurate tests with multiple carburetors without the need to manipulate each bowl’s levels to determine maximum knock.


CFR Crankcase

The CFR crankcase is a heavy-duty cast box-type design that provides both strength and rigidity for the loads produced by various types of fuels. Heavy-duty 3-inch main crankshaft journals and bearings and sturdy crankcase construction are designed for long service when operated and maintained properly. Removable side doors allow for easy access to critical internal components for inspection, maintenance and repair.


Intake Air Humidity Equipment

A humidity control system – either an ice tower and related equipment, or an intake air refrigeration unit – manages the moisture content of the combustion air going into the CFR octane rating unit. Maintaining humidity levels at a constant 25-50 grains of moisture /lb of dry air is prescribed by the ASTM method for producing consistent octane ratings.

Exhaust Surge Tank System

The CFR octane rating unit is equipped with a surge or expansion tank that eliminates the resonant pulsations and back pressure that occur in the CFR rating unit’s exhaust lines during operation. Eliminating these variables in the testing process provides consistent and accurate octane ratings.


XCP Digital Control Panel

The latest generation of CFR octane rating units combines the easy-to-use features of a digital control panel with the robust engine design that users expect from CFR. The CFR F1/F2 Combination Octane Rating Unit with XCP Digital Control Panel conforms to ASTM D2699 (RON), D2700 (MON), IP 236 and IP 237.

The fuel rating process takes a big step forward with the XCP Digital Octane Panel’s automated functions and enhanced documentation capabilities. The XCP Digital Octane Panel is intuitive and user-friendly, and operators require less training to achieve proficiency. With the XCP panel, the F1/F2 delivers more consistent and reliable test results, accurate data recording, comprehensive report generation, and improved productivity for operators at all skill levels.


XCP Panel: Features & Benefits

·      Easy-to-use touch-screen panel interface

·      Built-in prompts guide the operator through the test procedures for all of the ASTM methods. User-friendly interface produces consistent and reliable test results from operator to operator

·      Critical information for each rating is captured and displayed on screen with bold graphics and easy-to-read charts

·      Automated calculations and data logging for ease of use and greater accuracy

·      Digital knock meter displays actual knock intensity value, eliminating the need for visual interpretation of an analog meter by the operator

·      Non-contact laser sensor accurately measures cylinder height and displays results on-screen, providing more accurate test results

·      Electronic on-board barometer automatically corrects cylinder height for barometric pressure

·      Environmentally friendly RTDs for improved accuracy and management of critical temperature variables

·      Electronic maintenance log

·      On-screen reports, operations and maintenance manuals

Octane Analyzer
The digital Octane Analyzer option integrates with the XCP panel for a semi-automated fuel rating process that significantly reduces operator involvement and provides more consistent rating results. Using a bracketing procedure, the Octane Analyzer automatically sequences though the fuel sample and two primaries to determine octane numbers per ASTM methods. This process allows rapid selection and measurement of the fuel/air ratio for maximum knock value and reduces the time required to complete octane number determinations. The Octane Analyzer can run fuel samples in a bracketing mode in approximately 20 minutes for a full octane number determination.


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