Weichai Natural Gas System Main Parts Technical and Installation Requirements
Weichai gas system main parts technical & installation requirements
1. Pressure reducer
Installation requirements
●Pressure reducer is a supplied accessory and shall be mounted in places with little vibration and near to the engine with distance not exceeding 2m.
●It shall be installed behind the filter and installation position shall be convenient for regular adjustment, inspection and maintenance of pressure reducer.
●Pipeline connecting to pressure reducer shall be reasonably arranged and free from interferences.
●Pressure reducer gas outlet and the bottom shall not be upward to prevent fuel gas greasy dirt from back flowing into pressure reducer.
●Screw off the top cap and adjust the screw to pressure reducer valve, turn clockwise to thicken and anticlockwise to thin (Note: such mode of regulation is only applicable to high speed regulation).
2. Low pressure gas filter
Installation requirements:
●Gas filter installation position must be convenient for repair, cleaning and replacement;
●Within filter service life, pressure drop shall be less than 20kPa to guarantee system performance.
● Pay attention to arrow pointed airflow direction during installation
3. Mixer
Technical parameters: 1. Fuel type: natural gas, LPG, methane
2. Inlet pressure: -0.37kPa 3.Working temperature: —40℃~121℃
Installation requirements and operating instructions:
●Vertical installation
●Pay attention to arrow pointed airflow direction during installation
4. Wiring harness
Installation requirements:
●Wiring harness is not allowed to be laid at exhaust pipe side to avoid high temperature damage. Wiring harness is more than 150mm away from exhaust pipe and vortex end of turbocharger;
●Wiring harness shall be fixed reliably to prevent interference or friction with sharp matters. If not, please take protective measures.
●Wiring harness shall be free from intertwining and overlapping and reasonably aligned, convenient for later maintenance.
5. Engine control unit (ECU)
ECU collects inlet manifold pressure (MAP), inlet manifold temperature (MAT), engine phase, revolving speed, outlet water temperature, exhaust oxygen concentration and other signals and controls the action of electronic throttle, ignition timing and ignition orders after calculation so as to accomplish electronic control of engine. Engine control unit (ECU) shall be installed in control panel to realize real-time monitoring of engine parameters.
6. Inlet temperature, pressure sensor (T/MAP)
T/MAP sensor integrates pressure and temperature measurement. Engine control unit (ECU) uses sensor signals to calculate engine’s mixture air input.
7. Revolving speed sensor
Revolving speed sensor is mainly used to measure engine’s revolving speed. Engine control unit (ECU) uses revolving speed to control many parameters, including air input, ignition advance angle, etc. Control requirements of these parameters need engine control unit (ECU) to know engine’s camshaft position (for example which cylinder is ignited) and revolving speed.
8. Water temperature sensor
Water temperature sensor is mainly used to measure cooling water temperature. ECU may regulate idle speed and ignition advance angle in different water temperatures according to ECU stored data.
9. Oxygen sensor (UEGO)
Oxygen sensor is used to measure oxygen concentration in exhaust gas and transfer it into electrical signal for the use of ECU so as to monitor engine’s air-fuel ratio.
Installation requirements
●Installation position of oxygen sensor plays an important part in system’s work accuracy, so it must be installed strictly in accordance with specific requirements.
●It shall be installed 3～5 times of exhaust pipe diameter away from downstream of turbocharger outlet or exhaust elbow;
●It cannot be installed on exhaust elbow;
●In order to prevent oxygen sensor from being burned on exhaust pipe and for the convenience of disassembly, thread shall be smeared with anti-burning glue during the installation of oxygen sensor;
● Oxygen sensor wiring harness and connectors shall be kept away from exhaust pipe to avoid caking;
Height of oxygen sensor screw seat welded on exhaust pipe shall be less than 10mm and length of oxygen probe in exhaust pipe shall not be less than 13mm;
●Large gas consumption and unstable revolving speed occur when sensor is in failure or wiring hardness and connector is in bad contact;
●Oxygen sensor shall be installed on the exhaust pipe (circumferential), facing away from the engine;
●Oxygen sensor satisfying above mentioned conditions shall be close to turbocharger.
10. Revolving speed sensor
Revolving speed sensor is mainly used to measure engine’s revolving speed. Engine control unit (ECU) uses revolving speed to control many parameters, including air input, amount of fuel, ignition advance angle, etc. Control requirements of these parameters request the engine control unit (ECU) to know engine’s camshaft position (for example which cylinder is ignited) and revolving speed
Technical parameters:
1.Normal working temperature: measuring terminal: -40℃～150℃; plugging terminal: -40℃～ 120℃;
2. All magnetic field allowable: ≤2KA/m
3. Maximum torque allowable shall be 8N•m during assemble (when 8.8 M6X12 bolts are used), installation gap shall be 0.5~1.5mm.
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