Off-Highway Utility Engine Testing

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					                                            Off-Highway/Utility Engine Testing                                                                                                            Automotive

                                            using the LogBook/360™                                                                                                Application Note #71

                                            Application Summary                                                                              Greg Knott, Senior Application Engineer at the
                                                                                                                                             Kawasaki Small Engine Div. Lab, finds that air/fuel
                                            Small gasoline-powered engines intended for util-
                                                                                                                                             ratios and engine speed under load are the most
                                            ity vehicles, golf carts, and garden or lawn tractors
                                                                                                                                             critical indicators of engine behavior. He measures
                                            are typically designed, built, and emissions cali-
                                                                                                                                             oxygen content at the output of the oxygen sensors
                                            brated at the factory, but they need to be fine
                                                                                                                                             located in the exhaust manifold and translates the data
                                            tuned in the field to fit each application. The one
                                                                                                                                             to an accurate measure of the intake air/fuel ratio.
                                            or two-cylinder engines that reside in this cat-
                                            egory usually range from four to 29 hp and are first                                             Knott tests single-cylinder and twin-V cylinder en-
                                            characterized on a dynamometer bench to verify                                                   gines, both air cooled and liquid cooled. He supports
                                            torque, horsepower, emissions, and overall per-                                                  some R & D and manufacturing efforts, but prima-
                                            formance. But the loads they encounter while                                                     rily analyzes warranty issues and works with cus-
                                            mounted on a vehicle impose more rigorous con-                                                   tomers during the initial installation of engines in
                                            ditions. The engines must survive shock, vibra-                                                  their vehicles. The pre-production vehicles include
                                            tion, and other dynamics for a predictable life                                                  utility vehicles, riding lawnmowers, and commer-
                                            cycle. Kawasaki Motors Corp., USA, manufactures                                                  cial walk-behind mowers made by leading commer-
                                            a comprehensive family of such engines, and their                                                cial manufacturers such as John Deere and Toro. The
                                            Grand Rapids, Mich., facility field-tests and fine-                                              data acquisition equipment Knott needs to make
                                            tunes the engines while mounted in a wide variety                                                these measurements must be rugged enough to
                                            of vehicles. Each one is instrumented to record                                                  survive relatively rough treatment while mounted
                                            engine load, rpm, fuel consumption, temperature,                                                 on lawn and garden tractors, operate from the vehicle
                                            pressure, and air/fuel ratios, simultaneously.                                                   battery, and provide accurate data.

                                                                                                                                                         Potential Solution
                                                                                              Engine oil                                                 When Knott first joined the lab, he used an
                                                                                              Cooling air
                                                                                                                                                         existing data acquisition system to collect

           LBK1 - Remote
                                                                                              Intake air
        operation terminal
                                                                                              Carburetor float bowl (carburetor engines only)
                                                                                              Spark plug seat temps                                      the data he needed, but it had one out-
                                                                                              Coolant temperature (liquid cooled engines only)
                                           DBK cards      DBK19
                                                          14-channel high-accuracy            Ambient
                                                                                                                                                         standing limitation, measurements at a
                                            inside        thermocouple expansion card
                                                                                              Engine RPM
                                                                                                                                                         rate of only one sample every two seconds.
                                                                                                                                                         The unit is small and portable, but the low
                                                                                              Axle/Vehicle RPM
                                                          DBK7                                                                                           sampling rate cannot provide critical in-
                                                          4-channel frequency-input card
                                                                                              Ingnition signal                                           formation contained in the rpm data stream
                                                                                              Injector signal (fuel injected engines only)
                                                                                              Battery voltage
                                                                                                                                                         such as surging and drooping under field
                                                                                              O2 sensors, A/F ratio
                                                                                              Pressure sensors
                                                                                                                                                         operating conditions. In addition, its accu-
                                                          8-channel high-voltage input card                                                              racy often was not sufficient for many
                                                                                                         Engine RPM                                      other measurements, such as pressure and
                                                                                                                          Cooling air temperature        spark plug profiles. Says Knott, “When we
                                                                                                                                                         are just measuring temperature, or another
 1 - Air filter
                                                                                                                                                         variable with limited dynamic range, then
 2 - Intake manifold
 3 - Exhaust system
                       Pressure sensors                    1                                                                                             it’s fine. But when we want to observe and
                                             3             2                                                                    Engine oil temperature   record engine surges or fluctuating rpm,
                                          system                                                                                                         we don’t have the accuracy or mobility to
                                                                                                                                                         do that with this data acquisition system.”
                               O2 sensor, A/F ratio

                             Intake air temperature                                                                                                      IOtech’s Solution
                                                   Carburetor float
                                                 bowl temperature
                                                                                                                                                         Knott’s predecessor had evaluated other
                                                                                                            Engine RPM                                   data acquisition systems and eventually
                                              Spark plug seat temperature
                                                                                                                                                         purchased an IOtech LogBook/360™. Al-
                                                                                                                                                         though Knott wasn’t trained in its use, he
                                                                                                                                                         learned how to set it up and program it in
Kawasaki designs and manufactures a family of small, carbureted and fuel-injected engines                                                                only two days — with no more help than
for a wide variety of off-highway vehicles. The Small Engine Div. Lab in Grand Rapids,                                                                   the user’s manual. “It’s extremely easy to
Mich., uses IOtech LogBook data acquisition systems to field-test and fine-tune the engines                                                              set up, switch between tests, and make
in its customers’ pre-production vehicles. The most critical measurements that indicate                                                                  changes to software and hardware. You
effective and efficient operation include air/fuel ratios and engine speed under load. • IOtech, Inc. • 25971 Cannon Rd • Cleveland, OH 44146 • (440) 439-4091 • Fax (440) 439-4093 •

can input voltages and it automatically       carburetor. He looks at temperatures at                 Conclusion
calculates the specific unit of measure       the spark plugs, intake manifold, exhaust,
                                                                                                      Kawasaki engineers use the LogBook/360s
you need. What’s more, the LogBook’s          cooling air, and a variety of other areas,
                                                                                                      to fine tune small gasoline engines for indi-
sampling frequency is pretty amazing          depending on the engine type.
                                                                                                      vidual applications that include lawn and
compared to the others; we run very large
                                              The high sample rate is essential not only to           garden tractors and mowers from four to 29
sampling rates, from 4 to 6 kHz.”
                                              rpm, but voltage measurements on the fuel               hp. Each installation requires rpm, air/fuel
                                              injection systems. Knott can trace all spark            ratio, and cooling air temperature measure-
Knott’s primary concerns deal with in-
                                              plug firings, 3600 times per minute. He sees            ments to ensure the engine performs opti-
stalled engine emissions and cooling.
                                              the spark plug wave shape containing 4 or               mally for its intended use. The LogBook
The original emissions work is done in
                                              5 critical points and the signal through the            provides more than sufficient accuracy,
Japan, but a problem often crops up
                                              grounding system when killing the engine                dynamic range, mobility, and ease of use
when he installs an engine after having
                                              by grounding the spark plug.                            required for the tests.
initially set the emissions on the bench.
“We have to adjust the emissions differ-
ently when it finally goes in a tractor,”                                                  LogBook
says Knott. “Also, because we experi-
ence a lot of different air flows depend-
                                                The LogBook ™ combines on-board intelligence and a large capacity PC-Card removable
ing on the design of the hood, deck, or
                                                memory, with the industry’s easiest and most powerful data logging software. Its 16-bit,
engine cover, we check the air flow in          100-kHz A/D and triggering capabilities make it ideal for collecting high and low speed
the tractor to make certain the cooling         phenomena. A comprehensive array of signal conditioning expansion cards and
flow is sufficient and not obstructed or        modules are offered that allow the LogBook to take measurements from virtually
limited in any way.” Before Knott had           any transducer, from thermocouples to accelerometers.
the IOtech LogBook, he couldn’t drive
the machine while observing the engine          Features
speed under either full or partial load.        • Operates without a PC at the test site
But now he can trace the rpm and watch
                                                • 16-bit, 100-kHz analog and digital sampling
the engine perform. With the rpm take-
off set to 200 or 1000 Hz, Knott can see        • Compact yet expandable architecture can
                                                  accommodate over 400 channels of analog,
if it is drooping or surging. “I can drive
                                                  digital, and frequency I/O
500 miles on the tractor, and I don’t
have to be plugged into the wall outlet         • Stand-alone nonvolatile storage of over 250 million
                                                  samples via removable PC-Card memory
anymore,” Says Knott.
                                                • Card swapping and uploading during acquisition allows continuous data acquisition
Knott also measures air/fuel ratio, tem-        • Communication with PC via RS-232, parallel port, modem, or by transporting a PC-Card;
perature, and pressure with the LogBook.          optional RS-422 interface
The oxygen sensor measures O2 content,          • Built-in analog inputs support 14 programmable ranges up to 20V
and by virtue of a software package, con-       • Synchronous, mixed signal acquisition of analog, digital, and counter inputs
verts it to air/fuel ratio. The O2 sensor’s
                                                • Optional modem support provides remote communication
output signal passes through a signal con-
ditioner and then connects to the               • Optional GPS support (LogBook/360 only) logs location information
LogBook. The conditioner converts the           • Optional control terminal provides channel inspection, and acquisition queries
O2 content to a voltage directly propor-        • AC or DC powerable
tional to the A/F ratio. “So I plug a for-
mula into the LogBook and an internal           Software
function automatically converts the volt-       • Includes LogView™ Out-of-the-Box™ software for easy setup, calibration, & more; no
age directly to the new unit of measure,          programming required
air/fuel ratio,” says Knott.                    • Simple spreadsheet-style interface provides powerful setup features for immediate startup
                                                • Acquisition configurations can be transported to the LogBook via PC-Card, serial port,
Knott also measures numerous tempera-
                                                  parallel port, or modem connection
tures. For example, he instrumented a
tractor recently for oil temperature, cool-     • Provides direct support for a wide variety of transducers
ing-air temperature, and ambient tem-           • Includes eZ-PostView™ for post-acquisition data viewing
perature. He also frequently monitors the
coolant temperature of a liquid-cooled          DBK7™, DBK8™, DBK19™, eZ-PostView™, LBK1™, LogBook/360™, LogView™, and Out-of-the-Box™ are the property of
                                                IOtech; all other trademarks and tradenames are the property of their respective holders. 030702.
engine and the fuel temperature near the • IOtech, Inc. • 25971 Cannon Rd • Cleveland, OH 44146 • (440) 439-4091 • Fax (440) 439-4093 •

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Description: Off-Highway Utility Engine Testing