ASTM D6593 test method for evaluation of automotive engine oils
ASTM D6593 standard test method for Evaluation of Automotive Engine Oils for Inhibition of Deposit Formation in a Spark-Ignition Internal Combustion Engine Fueled with Gasoline and Operated Under Low-Temperature, Light-Duty Conditions
4. Summary of Test Method
4.1 Each test engine is assembled with many new parts and essentially all aspects of assembly are specified in detail.
4.2 The test stand is equipped to control speed, load, AFR, and various other operating parameters.
4.3 The test is run for a total of 216 h, consisting of 54 cycles of 4 h each. Each cycle consists of three stages.
4.4 While the operating conditions are varied within each cycle, overall they can be characterized as a mixture of low-temperature and moderate-temperature, light and medium duty operating conditions.
4.5 To accelerate deposit formation, the level of oxides of nitrogen in the blowby and the rate of blowby into the crankcase are significantly increased. The fresh air breathing of the crankcase is eliminated and the oil and coolant temperatures are lowered to induce condensation of water and fuel.
4.6 The performance of the test engine oil is evaluated at the end of the test by dismantling the engine and measuring the level of deposit formation.
5. Significance and Use
5.1 This test method is used to evaluate an automotive engine oil's control of engine deposits under operating conditions deliberately selected to accelerate deposit formation. This test method was correlated with field service data, determined from side-by-side comparisons of two or more oils in police, taxi fleets, and delivery van services. The same field service oils were then used in developing the operating conditions of this test procedure.
5.2 This test method, along with other test methods, defines the minimum performance level of the API Category SL (detailed information about this category is included in Specification D4485). This test method is also incorporated in automobile manufacturers' factory-fill specifications.
5.3 The basic engine used in this test method is representative of many that are in modern automobiles. This factor, along with the accelerated operating conditions, should be considered when interpreting test results.
