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
9. Measurement Instrumentation
9.1 Temperatures:
9.1.1 Equipment:
9.1.1.1 Temperature measurement locations for the six required temperatures are specified. Use thermocouples that are calibratable to 0.5°C. Use only OEM temperature sensors for EEC inputs.

9.1.1.2 All thermocouples, except the intake-air thermocouple, shall be premium and sheathed. The intake-air thermocouple may be an open-tip type. Thermocouples shall be either 1/8 in. diameter by 4 in. long or 3 mm diameter by 100 mm long. Thermocouples, wires, and extension wires should be matched to perform in accordance with the special limits of error as defined in ANSI MC96.1.

9.1.2 Engine Coolant Inlet - Install the sensor in the outlet perpendicular to the run of the tee fitting. Install sensor with the tip in the center of the stream of flow, directly opposite of the perpendicular outlet. Locate the tee fitting 300 to 400 mm upstream from the water pump inlet (see Fig. A3.18).

9.1.3 Engine Coolant Outlet - Install the temperature sensor in the modified thermostat housing. Locate the tip of the temperature sensor in the center of the stream of flow and is located in the thermostat housing neck within 8 cm of the housing outlet.

9.1.4 Engine Oil Inlet - Install the tip of the sensor at the center of the flow stream through the external oil filter adapter (see Fig. A3.8). Tip of sensor shall be even with the machined surface of the oil filter adapter.

9.1.5 Engine Oil Outlet - Install the tip of the sensor at the center of the cross fitting attached to the bottom of the heat exchanger (see Fig. A3.8). Locate the sensor along the same axis, but opposite, the outlet port connected to the heat exchanger. The tip shall be within 2 mm of the center distance between the external most surfaces of the outlets along the axes.

9.1.6 Intake Air - Install the tip of the thermocouple mid-stream in the air cleaner (see Fig. A3.1). Insertion depth shall be 55 more or less 2 mm.

9.1.7 RAC Coolant Inlet - Install the tip of the thermocouple at the center of the cross fitting before the inlets of the RAC's (see Fig. 6, item 8). Locate the sensor along the same axis, but opposite the inlet port of the incoming fluid. The tip shall be within 2 mm of the center distance between the external most surfaces of the outlets along the axes.

9.1.8 Calibration - Calibrate all thermocouples prior to a reference oil test. The temperature measurement system shall indicate within more or less 0.5°C of the laboratory calibration standard. The calibration standard shall be traceable to NIST.

9.2 Pressures:
9.2.1 Equipment - Pressure measurement for each of the eight required parameters is detailed in the following sections. This allows reasonable opportunity for adaptation of existing test stand instrumentation. However, the accuracy and resolution of the pressure measurement sensors and the complete pressure measurement system shall follow the guidelines detailed in ASTM Research Report RR:D02–1218. Replace pressure sensors that are part of the EEC system with only Ford specified equipment.

NOTE 5 - Tubing between the pressure tap locations and the final pressure sensors should incorporate condensate traps, as indicated by good engineering practice. This is particularly important in applications where low air pressures are transmitted by means of lines which pass through low-lying trenches between the test stand and the instrument console.

9.2.2 Intake Manifold Absolute - Measure the manifold absolute pressure at the port on the top side of the throttle body spacer (see Figs. A3.2 and A3.27).

9.2.3 Engine Oil - Measure oil pump pressure at the bottom port of the oil filter adapter housing on the engine block (see Fig. 5 and Figs. A3.24 and A3.25). Take cylinder head oil pressure measurements on the sides of the cylinder heads on the rear of the left cylinder head and front of the right cylinder head (see Fig. 5 and Figs. A3.23 and A3.26). Use individually dedicated pressure sensors.

9.2.4 Engine Coolant Pressure - Measure engine coolant pressure at the top of the coolant reservoir as shown in Fig. A3.18.

9.2.5 RAC Coolant - RAC coolant pressure can be measured at the coolant inlet cross fitting as is done with temperature although monitoring of RAC pressure is not required. Pressure should remain adequate as long as temperature and flow are within the limits of Table 2.

9.2.6 Fuel - Measure the fuel pressure near the injector rail inlet as shown in Fig. 1. When utilizing a pressure gage mounted directly to the injector rail, the gage should be a damped, liquid-filled type. (Warning - Too much weight attached to the fuel rail may cause it to leak. Any instrumentation attached to the fuel rail should be supported by something other than the fuel rail.)

9.2.7 Intake Air - Measure the intake-air pressure in the air cleaner housing in the location shown in Fig. A3.1. Insertion depth of the probe shall be 50 more or less 2 mm. If a manometer is used, install a liquid trap to prevent manometer fluid from entering the intake-air cleaner.

9.2.8 Crankcase - Measure the crankcase pressure at the dipstick tube. The sensor shall be capable of measuring positive and negative pressure. If a manometer is utilized, install a liquid trap to prevent manometer fluid from entering the crankcase.

9.2.9 Exhaust Back Pressure - Measure the exhaust back pressure with the exhaust gas sampling probe located down-stream in the Y (see Fig. A3.16). A sensor capable of absolute or gage measurement corrected with barometric pressure reading is recommended. Install a condensate trap between the probe and sensor to accumulate water present in the exhaust gas.

9.2.10 Calibration - Calibrate all pressure measurement sensors prior to a reference oil test. The MAP pressure measurement system shall indicate within 0.1 kPa of the laboratory calibration standard. All other pressure measurement systems shall conform to the guidelines in ASTM Research Report RR:D02–1218. The calibration standard shall be traceable to NIST.

9.3 Flow Rates:
9.3.1 Equipment - Flow rate measurement for each of the four required parameters is detailed in the following subsections. With the exception of the engine coolant and blowby flow rates, measurement equipment is not specified for a given parameter. This allows reasonable opportunity for adaptation of existing test stand instrumentation.

9.3.2 Engine Coolant - Determine the engine coolant flow rate by measuring the differential pressure drop across the specified venturi flowmeter (see Fig. A3.18) Flowmeter is available from the supplier in X2.1.6. Take precautions to prevent air pockets from forming in the lines to the pressure sensor. Transparent lines or bleed lines, or both, are beneficial in this application. Ensure that the manufacturers required straight sections of pipe are installed immediately up and down stream of the flowmeter.

9.3.3 RAC Coolant - Measure the total volumetric coolant flow rate through the RAC system and the individual RAC flowrates as shown in Fig. 6.

9.3.3.1 Calibration - Calibrate the flowmeters used in the measurement of both the engine coolant flow rate and RAC coolant flow prior to a reference oil test. Calibrate the flowmeters as installed in the system at the test stand with test fluid. Calibrate the flowmeters with a turbine flowmeter or by a volume/time method at Stage I operating conditions.

9.3.4 Blowby:
9.3.4.1 Measure the blowby flow rate using the apparatus shown in Fig. 7. The measurement system routes the blowby through an external, sharp-edged orifice and into the engine intake manifold by means of an auxiliary (dummy) PCV valve. Maintain crankcase pressure at 0.0 more or less 25 Pa during operation of the system to minimize the potential for crankcase leakage. Mount the dummy PCV valve and orifice plate in a vertical position.

9.3.4.2 Determine the blowby flow rate by measuring the differential pressure drop across the sharp-edged orifice; an inclined manometer or differential pressure sensor is required for measurement of the differential pressure drop. The differential pressure drop sensor shall have a range from 0 to 1 kPa.

9.3.4.3 The sharp-edged orifice assembly is specifically designed for blowby flow rate measurement and shall be fabricated in strict compliance with the specifications that are available from the TMC. Additional information on the orifice system can be obtained from the source listed in X2.1.8 The assembly contains five orifices. The 0.375 in. orifice is generally satisfactory for the range of blowby flow rate encountered. The complete orifice assembly can also be purchased from the supplier listed in X2.1.11.

9.3.4.4 Maintenance - As a minimum, clean the blowby measurement apparatus weekly. Replace the o-rings with each cleaning. Exercise particular care when cleaning the orifice meter assembly. Clean the three-way valve by soaking the valve in agitated organic solvent (see 7.7.3) until clean, followed by hot (> 60°C) water rinse and spray rinse with aliphatic naphtha. Use compressed air to force air-dry. Inspect the port passages and remove any carbonaceous deposits by scraping. If the valve is disassembled for cleaning, make sure the core is properly seated upon reassembly.

9.3.4.5 Calibration - Calibrate the blowby orifice meters used for laboratory measurements standards every six months. Calibrate laboratory blowby measurements standards, not used for production, yearly. The calibration standard shall be traceable to the NIST. Calibrate the temperature measuring devises in the blowby system every six months. (Warning - Internal leakage within the three-way valve may cause some of the blowby gas to pass directly to the intake manifold from the test PCV valve and result in erroneous blowby flow rate measurements (see Fig. 7).)

9.4 Fuel Consumption - Determine the fuel consumption rate by measuring the amount of make-up fuel flowing from the external fuel tank. The measurement point is upstream of the return flow from the fuel rail (see Fig. 1).

9.4.1 Calibration - Calibrate mass flowmeter or gravimetric systems prior to each reference oil test. Volumetric systems shall be temperature and specific gravity compensated and calibrated against a mass flow device. The flowmeter located on the test stand shall be within 1 % of the calibration standard.

9.5 Speed and Load:
9.5.1 Required Capabilities - The dynamometer speed and load control systems shall be capable of maintaining the limits specified in Table 2 and meet the ramping requirements specified in Table 4. These limits require control within more or less 0.9 % for operation during Stages I and II. Because the dynamometer and driveline frictional losses may approach the Stage III load, manage the control input and system response during Stage III carefully to maintain engine operation within the specified tolerances. These tolerances are necessary to maintain a stable air-fuel ratio during Stage III. Hydraulic dynamometers have a high residual load and are not suitable for operation during Stage III.

9.5.2 Suitable Systems - Utilize a full closed-loop system using a dry gap dynamometer. A typical closed-loop system maintains engine speed by varying dynamometer load and maintains engine load by varying the engine throttle position. The total driveline inertia through to the dynamometer, excluding the engine flywheel, shall be 0.8 more or less 0.1 kg-m2.

9.5.3 Calibration - Calibrate the load measurement and readout system with deadweights at least once per test. Calibration of the zero scale readout is recommended once per day during the oil level soak period. Calibrate the speed measurement system prior to a reference oil test.

9.6 Exhaust Gas:
9.6.1 Equipment:
9.6.1.1 Determine the air-fuel ratio using a device to measure Lambda. A suitable device is available from the supplier listed in X2.1.

9.6.1.2 Calibrate the Lambda measurement device by introducing the sensor to air prior to a reference oil test.

9.6.2 Calibration (General) - Calibrate the exhaust gas analysis equipment before each set of measurements taken during the test. The calibration technique should compensate for the flow rate sensitivity of the exhaust gas analysis meters.

9.7 Humidity:
9.7.1 The intake air humidity is recorded using the laboratory's primary humidity measurement system. Make corrections to each reading, for non-standard barometric conditions, using an additive correction derived from the perfect gas law.

9.7.2 Primary Measurement System Calibration - The primary laboratory measurement system is calibrated at each stand on a semi-annual basis using a hygrometer with a minimum dew point accuracy of more or less 0.55°C at 16°C (more or less 1°F at 60°F). The calibration consists of a series of 20 paired measurements between the primary laboratory system and the calibration hygrometer (see Table 5 for an example). The measurement interval shall be appropriate for the time constant of the humidity measuring instruments and the control system. Comparison periods of 20 min to 2 h, with measurements recorded at 1 to 6 min intervals, are typically acceptable. The measurements taken with the calibration hygrometer are corrected to standard barometric pressure (101.1 kPa [29.92in. Hg]) using the perfect gas law. The sample line shall be non-hygroscopic. Exercise precaution to prevent condensation of the sample.

9.7.3 The difference between each pair is computed and used to form a mean and standard deviation. The absolute value of the mean difference cannot exceed 10 grains/lb [1.4 g/kg], and the standard deviation cannot exceed 0.71 g/kg [5 grains/lb]. Both of these requirements shall be met to consider the primary humidity measurement system to be calibrated. If either of these requirements cannot be met, the laboratory shall investigate the cause, make repairs, and recalibrate. The calibration data is maintained for two years.

9.7.4 Sample Location - The calibration sample tap is located on the air line to the engine, between the main duct and entrance to the air filter housing.