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Automatic diesel fuel heating systems (ÑÏÀ) are intended for the integrated solution of the diesel fuel heating using the above-mentioned separate heaters combined into the integrated system controlled by autonomous electronic unit. ÑÏÀ perform a pre-starting and propulsion fuel heating without a driver and facilitate significantly diesel-powered vehicle operation in winter season. In addition to the heaters ÑÏÀ include fuel temperature sensor (Ä1) and control unit (ÁÓ1) mounted in the engine compartment as well as remote control panel (ÏÓ1) mounted in the driver’s cabin. For the automatic control over a liquid fuel heating in the heated standpipes ÑÏÀ are equipped with tee electromagnetic valve (ÊÐ1). The ÑÏÀ control unit has 12V supply voltage for the ÑÏÀ-101 and 24V – for the ÑÏÀ-201. ÁÓ1 is connected directly to the vehicle battery (power supply) and to the ignition key (switching-on). The ÑÏÀ control panel has a mode switch for automatic heating control and manual heating control – each heater is switching-on and off manually. Fuel heating system provides: automatic heating switching-on at fuel temperature drop below the heating temperature limit; automatic heating switching-off at fuel temperature increase above the heating temperature limit; operational programmed control with heating mode and time modification depending on a fuel temperature; heating shutoff at vehicle-system voltage drop below threshold level, at the heater failure, at short circuit. Under the automatic control mode ÁÓ1 is activated when you turn the ignition key at the first operating position. At the initial time the current temperature of the fuel in the target fuel line point is determined by the temperature sensor Ä1 (usually in the front of the fine filter, at the flow-type heater inlet or in the front of the filter-separator). At the engine starting after long-term interruption this temperature is identified by ÁÓ1 as the cold engine temperature or as the engine starting ambient temperature. Then depending on the fuel temperature value and the ÑÏÀ configuration ÁÓ1 develops the required pre-heating algorithm and implements it according to the specified ÑÏÀ program. At this time powered-on heaters indication is lighted on the ÏÓ1. A signal to start the engine is appeared on the remote control panel after the pre-heating. If the pre-heating is not required by temperature fuel value on the Ä1, the ÏÓ1 signals immediately to start the engine. At the propulsion heating ÁÓ1 constantly monitors the fuel temperature from the sensor Ä1 and according to the ÑÏÀ configuration switches on electric or combined electrical and fluid heating when the temperature drops below the maximum heating temperature equal usually to plus (5±3)°C. The heating is automatically turned off when the fuel temperature in the fuel line is above the heating temperature limit.
Examples of the automatic ÑÏÀ operation mode. Example 3. When you run the diesel engine with the ÑÏÀ configuration presented in the Example 1 («Usability guideline» section) the fuel temperature from the sensor Ä1 was -15°C. For this case at the pre-heating mode ÁÓ1 simultaneously switches on the fine filter heater ÏÁ-101 for the estimated time of 5 minutes and the electric fuel standpipe nozzle heater ÍÒÏ-101 for 3,5 minutes. Then in the propulsion heating mode depending on the current fuel temperature below or above the maximum heating temperature, the flow-type heater ÏÏ-101 automatically switches on and off. Example 4. When you run the diesel engine with the ÑÏÀ configuration presented in the Example 2 («Usability guideline» section) the fuel temperature from the sensor Ä1 was -30°C. Because of the total electric power consumption for the pre-heating (390 W) is above admissible energy consumption standards equal to 350 W, ÁÓ1 primarily switches on fine filter heating with two sequentially established ÏÁ-101 24Â (240 W) for the estimated time of 7,5 min, and then after ÏÁ-101 disabling it switches on the electric fuel standpipe heater ÒÏ-301/520 24Â (150 W) for 4 min. In the propulsion heating mode at a fuel temperature below the maximum heating temperature ÁÓ1 switches on the flow-type heater ÏÏ-102 and simultaneously puts off ÊÐ1 from the position 0 to the position 1 of hot coolant supply from the cab heater to the liquid fuel standpipe heater. Combined electric and liquid heating continues until the fuel heating temperature limit excess. Then ÁÓ1 turns off electric heating and controls liquid heating according to the upper and lower control fuel temperature. The upper control temperature is +(24±3)°C and is the upper permissible fuel temperature for the optimum performance of the fuel backup and fuel injection pumps. The lower control temperature in this case equals to the maximum heating temperature. When the temperature exceeds the upper pilot level ÁÓ1 turns off the liquid heating by switching ÊÐ1 to the original position 0. If in time the fuel temperature drops again below the heating temperature limit the ÁÓ1 switches on both electric and liquid heating and propulsion heating cycle. The delivery set includes: packed ÑÏÀ kit (control unit, remote control, fuel temperature sensor, electromagnetic valve – clamps on consumer request), wiring kit for connection to the power-supply system, certificate, installation and maintenance manual. Ordering model designation: Automatic heating system ÍÎÌÀÊÎÍ™ ÑÏÀ-101-ÊË1 12Â, èëè ÑÏÀ-201 24Â, where ÑÏÀ-1 – model designation; 01 – modification number; - ÊÐ1 – electromagnetic valve for the liquid fuel standpipe heating control; 24Â – power-supply system voltage, V |
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