Small craft - Measurement of human exposure to hand-transmitted vibration from tiller handle operated outboard motors

Transcription

1 Small craft - Measurement of human exposure to hand-transmitted vibration from tiller handle operated outboard motors Introduction This ICOMIA Standard describes the method for determining the equivalent handtransmitted vibration level to which the operators of tiller handle steered outboard motor powered recreational craft are exposed during typical operation as determined by duty cycle studies. ICOMIA 1994 [Revised 2013] 38/1

2 Contents ICOMIA Standard No Rev. 1 1 Scope References Definitions Type tests Monitoring tests L hdc Measurement equipment Equipment specifications Equipment calibration Object under test, test conditions and installation Object under test Operating condition of outboard motor Specifications of "standard craft" Measurement location Test procedure Calculation of port-starboard and vertical acceleration levels, Lps; and Lv;, at each mode Calculation of duty cycle acceleration level Five mode measurement -E4 duty cycle Five mode measurement E5 duty cycle Duty cycle hand vibration acceleration level (L psdc and L vdc ) calculation Test report (test record) Data identifying the outboard motor Data on installation and operating condition during measurement Test conditions Instrumentation Quantities measured and calculated results Location of test, date of test and person responsible for the test ICOMIA 1994 [Revised 2013] 38/2

3 1 Scope This standard is intended to be used in conjunction with ISO (E), and provides the basis for determining the vibration (acceleration) level generated at the handle of tiller handle steered outboard motors, using standard methods so as to obtain reproducible results. 2 References ISO (E) "Mechanical vibration -Guidelines for the measurement and the assessment of human exposure to hand-transmitted vibration." ISO "Reciprocating internal combustion engines -Exhaust emission measurement -Test cycles for different engine applications." ISO 8665: 1994 ISO 8666 DAM IS "Small craft -Marine propulsion engines and systems -Power measurements and declarations" "Small craft -Hull length -Measurement" (draft standard) "Small craft -Hull identification -Coding system" (draft standard) ICOMIA Std. 41/94 "Small craft -Measurement of sound pressure level of airborne sound emitted by powered recreational craft" (ICOMIA = International Council of Marine Industry Associations) 3 Definitions 3.1 Type tests Measurements performed to certify the vibration (acceleration) level generated at the handle of tiller handle steered outboard motors. 3.2 Monitoring tests Measurements performed to check that the vibration (acceleration) level has not changed since type test certification or after modification, as applicable. ICOMIA 1994 [Revised 2013] 38/3

4 3.3 L hdc The duty cycle hand vibration acceleration level. 4 Measurement equipment 4.1 Equipment specifications The instrumentation system, including accelerometers, cables and any additional measuring equipment, for example a tape recorder and/or level recorder, shall satisfy the requirements specified in ISO (E). When a tape recorder is used for the measurements the dynamic range of the instrumentation shall be consistent with the measured signal. An engine speed tachometer which is accurate to within :t 50 revolutions per minute (r/min.) shall be used. 4.2 Equipment calibration The overall performance of the measurement equipment shall be checked according to the instructions of the manufacturer with a calibration exciter at the beginning and at the end of each series of measurements and not less than the beginning and end of each measurement day. At time intervals no longer than 2 years, the accelerometer and vibration meter shall undergo laboratory verification for compliance with manufacturer's specifications and any relevant standards. The calibration exciter used for calibration of the vibration meter shall undergo laboratory verification with traceability to a primary standards laboratory a minimum of once per year. The date of the last verification of the compliance shall be recorded. The calibration intervals listed above are intended to be minimum requirements. More frequent calibration intervals may be necessary for various reasons, including; use in hostile environments, situations where precise measurements are critical, after mishandling or other possibly damaging occurrence, or where the instrumentation has a past calibration history which suggests more frequent calibration is necessary. 5 Object under test, test conditions and installation 5.1 Object under test The object under test is the tiller handle steered outboard motor with all the accessories required for operation. ICOMIA 1994 [Revised 2013] 38/4

5 5.2 Operating condition of outboard motor In the test, the outboard motor shall be operated installed on a "standard craft" as specified in subclause 5.3. Propeller equipped outboard motors shall be tested with a standard propeller. The pitch of the propeller shall be such that at full throttle, the declared engine speed (± 4%) is achieved in the steady state with the standard craft traveling in a straight line on calm water. If the declared speed can not be obtained with the available propellers then it is allowed to modify the pitch and/or diameter of the standard propeller to achieve the correct declared engine speed. For controllable pitch propellers the pitch shall be fixed in the position required to obtain the declared engine speed at full throttle. Jet pump equipped outboard motors shall be tested with a standard impeller. The pitch of the impeller shall be such that at full throttle, the declared engine speed (± 4%) is achieved in the steady state with the standard craft traveling in a straight line on calm water. If the declared speed can not be obtained with the available impellers then it is allowed to modify the pitch and/or diameter of the standard impeller as well as the cross sectional area of the standard pump outlet nozzle to achieve the correct declared engine speed. In the case of engines without a speed governor the declared engine speed shall be the mid-point of the full throttle speed range recommended by the manufacturer for propeller/impeller selection. In the case of engines with speed governors the declared engine speed shall be the governed speed specified by the manufacturer. For outboard motors which are equipped with adjustable trim, the trim angle shall be adjusted so that the propeller/impeller thrust is parallel to the surface of the water within ±2 when the craft is stationary in the loaded test condition, hereafter referred to as level trim, for all test conditions. The outboard motor operating conditions (fuel used, run-up time, etc.) shall comply with the manufacturer's instructions. Measurements shall be performed on calm water and in the absence of precipitation. 5.3 Specifications of "standard craft" Any series production craft with a hull made of fibreglass reinforced plastic {FRP} and with a V-hull shape meeting the dimensional and weight characteristics of ISO Standard craft specifications for outboard motor type tests may be used as a standard craft (Table 4 in :2008). A variation of ±10% is allowed in the dimensional characteristics and a variation of ±20% is allowed in the weight of the craft. ICOMIA 1994 [Revised 2013] 38/5

6 5.4 Measurement location Measurements shall be performed in both the port-starboard (horizontal) and vertical directions as specifi~d in ISO (E). 6 Test procedure The engine speed (r/min.) shall be as stated in ISO (test cycle types E4 and E5) for the five modes as the following percentages of the declared speed; Engine speed The vibration acceleration level shall be measured as specified in ISO (E), at each engine speed, in the port-starboard and vertical directions. Note -Spark Ignition outboard motors shall be tested according to the E4 duty cycle, and diesel outboard motors shall be tested according to the E5 duty cycle The meter shall be observed while the craft proceeds in a straight line. When the vibration acceleration level reading stabilises within ±1 db, determine the central tendency of the readings to the nearest 0.5 db This reading is the vibration acceleration level to be recorded for each engine speed. Duty cycle E4 E5 Mode 1 idle idle Mode 2 40% 63% Mode 3 60% 80% Mode 4 80% 91 % Mode 5 100% 100% ICOMIA 1994 [Revised 2013] 38/6

7 7 Calculation of port-starboard and vertical acceleration levels, Lps; and Lv;, at each mode The port-starboard and vertical acceleration levels L psi and L vi at each mode i are calculated from the measured port-starboard and vertical r.m.s accelerations as: L = 20 psi log 10 a a psi 0 and; Lvi = 20 log 10 a a vi 0 where; L psi L vi a psi is the acceleration level in the port-starboard direction in mode i is the acceleration level in the vertical direction in mode i is the r.m.s. port-starboard acceleration in mode i, in metres per second squared a vi is the r.m.s. vertical acceleration in mode i, in metres per second squared a o is the reference acceleration of 1 µm/s 2 8 Calculation of duty cycle acceleration level 8.1 Five mode measurement -E4 duty cycle For spark ignition outboard motors input the calculated acceleration levels L psi and L vi into the following table and perform the calculations indicated in 8.3. i. % of rated Lpsi Lvi Time Fraction - ti rpm 1. Idle ICOMIA 1994 [Revised 2013] 38/7

8 8.2 Five mode measurement E5 duty cycle For diesel outboard motors input the calculated acceleration levels L psi and L vi into the following table and perform the calculations indicated in 8.3. i. % of rated L psi Lvi Time Fraction - t i rpm 1. Idle Duty cycle hand vibration acceleration level (L psdc and L vdc ) calculation Calculate the port-starboard and vertical duty cycle acceleration levels Lpsdc and Lvdc respectively by substituting the appropriate values into the following equations: and; L = 10 log psdc L = 10 log vdc L psi 5 = t 10 i i 5 Lvi = t 10 i i The reported duty cycle hand vibration acceleration level Lhdc shalr be the greater of the port-starboard level, Lpsdc and the vertical level, Lvdc. 9 Test report (test record) The test report shall give the designation of the method and the details specified in subclauses 9.1 to Data identifying the outboard motor a) Manufacturer b) Propulsion system type and serial number c) Declared propeller shaft power according to ISO 8665 d) Declared engine speed ICOMIA 1994 [Revised 2013] 38/8

9 e) Combustion process: Spark ignition engine or compression ignition engine f) Propeller specification 9.2 Data on installation and operating condition during measurement a) Type of craft used including Model number and Serial number (if available, hull identification number (HIN) according to ISO ) b) Actual speed of engine for all test conditions (see clause 6) 9.3 Test conditions a) Weather conditions b) Water conditions 9.4 Instrumentation a) Testing equipment used, including details on name of product, type, serial number and manufacturer b) Calibration method used, date and place of calibration 9.5 Quantities measured and calculated results a) Acceleration in port-starboard and vertical directions at each measuring point, apsi and avi respectively b) Acceleration level in port-starboard and vertical directions at each measuring point, Lpsi and Lhi respectively c) Duty cycle acceleration level in horizontal and vertical directions, Lpsdc and Lvdc respectively d) Duty cycle hand vibration acceleration level, Lhdc 9.6 Location of test, date of test and person responsible for the test ICOMIA 1994 [Revised 2013] 38/9