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PURPOSE Diesel fuel heating in winter season provides a reduction of its viscosity (increase in fluidity), prevents waxing in critical nodes of the main fuel line, reconditions and improves filtration capacity. Therefore, diesel vehicles operation under low temperature is significantly simplified by ensuring a stable fuel supply and purification in the pre-starting period as well as with the engine already running. Heaters by NOMACON™ applied in the fuel-supply systems of diesel engines are divided by their functional purposes:: - fine filter heaters (strap – band); - flow-type in-line heaters (installed in the standard fuel line gap at the front of the fine filters); - flexible tape heaters (for filters and fuel lines); - rod-type heaters (for filter-separators of various systems); - heated nozzles (for standard fuel standpipes); - heated standpipes (installed into the fuel tank in substitution of the conventional standpipes). The most vulnerable point of the main fuel line is the fine filter which becomes obstructed because of diesel fuel viscosity increase and wax crystals accumulation in it under low temperature conditions. Electric heater ÏÁ-101 by NOMAKON™ is made in the form of strap sleeve-band and intended for external installation over the fine filter frame. The heater is applied for preheating the fuel in the filter and operates from the car battery. Flow-type in-line heaters ÏÏ-101 (102), ÏÏ-201 (202) by NOMAKON™ are additional elements of the fuel system and installed in the standard fuel line gap at the front of the fine filters. Heaters provide electric heating of the fuel in the fuel line with the engine running, i.e. in the propulsion heating mode. Flexible tape heaters ÝÍÃË-1 are designed for external heat-insulation and electrical heating of the main fuel line elements (filter body, fuel lines) during the pre-starting period and with the engine running. Heated fuel standpipe nozzles ÍÒÏ-101 (102), ÍÒÏ-201 (202) by NOMAKON™ are developed for installation on regular fuel standpipe to ensure diesel fuel intake from the tank under low temperature conditions down to -40°C when the intake of the frozen and condensed fuel is impossible by standard fuel standpipe. Diesel fuel heating and accordingly its viscosity reduction and dewaxing are conducted by the nozzle’s electric heater operating on car battery (car system) power. Heated fuel standpipes ÒÏ-101 (102), ÒÏ-201 (202), ÒÏ-301 (302) by NOMAKON™ are essential elements of the vehicle heated fuel system and intended for the diesel fuel intake from the tank under low temperature conditions down to -40°C when the intake of the frozen and condensed fuel is impossible by standard fuel standpipe. In the pre-starting period fuel heating is conducted by fuel standpipe’s electric heater operating on car battery (car system) power. During engine operation fuel heating is conducted by heated return fuel – ÒÏ-101 (102) – as well as by heated fluid – engine cooling system antifreeze – ÒÏ-201 (202), ÒÏ-301 (302). Under low temperature conditions the simultaneous electric and liquid heating is provided. Electric rod heaters with heating elements ÏÑ-101 (102), ÏÑ-201 (202) by NOMAKON™ are developed for diesel fuel heating in various types of filter-separators of the engine fuel line. The heaters are analogues of the well-known models of fuel filter-separator heaters of Fleetguard FuelPro and Fleetguard DieselPro systems and their analogues – ÏÑ-101 (102), Mann-Hummel PreLine system and their analogues – ÏÑ-201 (202). The represented heaters in the fuel system provide pre-starting and continuous heating with the engine running. Automated heating systems ÑÏÀ-101 (201) (the ÑÏÀ) by NOMAKON™ are intended for the integrated solution of the problem of diesel fuel heating using the above-mentioned separate heaters combined into one integrated system controlled by electronic unit. In addition to the heaters ÑÏÀ include fuel temperature sensor and control unit mounted in the engine compartment as well as remote control panel mounted in the driver’s cabin. ÑÏÀ automate the heating process and simplify diesel-powered vehicle operation in winter season. Simultaneously ÑÏÀ perform protective functions in fault inception as well as during car-system voltage reduction. USABILITY GUIDELINE Long-term experience in production, sales and maintenance of diesel fuel heaters by NOMAKON™ showed their versatility (i.e. adjustability to any car) and high efficiency when using in various climate zones with temperatures down to -40°C. When choosing heaters and heating systems acquisition you should primarily use the following criteria: 1) Define an appropriate for your diesel vehicle boundary temperature for stable operation in winter; 2) Determine the admissible requirements of energy consumption (electric power) from the car system for the pre-starting and propulsion fuel heating. Below in Table 1 please find recommendations for the NOMAKON™ heaters use depending on the boundary temperature in order to secure the stable diesel car operation in winter season.
** - as a rule, on application of the heaters in the filter-separators the flow-type in-line heaters ÏÏ-101 (102), ÏÏ-201 (202) are not applied. Under the boundary temperature down to -5°C only the heater fine filter ÏÁ-101 may be used for pre-starting and if necessary for propulsion fuel heating. Under the boundary temperature down to -15°C, the optimum heating system will include the fine filter heater, flow-type in-line heater as well as heated low-powered nozzle ÍÒÏ-101 (102) upon a standard fuel standpipe or heated fuel standpipe ÒÏ-101 instead of the standard one. Furthermore, while the fine filter heater and heated nozzle (electric fuel standpipe heater) operate in the pre-heating mode, the flow-type in-line heater and liquid standpipe heater can provide diesel fuel heating with the engine already running, i.e. propulsion fuel heating mode. By applying the above-described heating system with more powerful heated nozzle ÍÒÏ-201 (202) for the standard standpipe or heated standpipe ÒÏ-102 with more powerful electric heater, or heated standpipe ÒÏ-201 (202) with additional liquid heating by hot coolant we can obtain even greater reduction of boundary temperature down to -25°C. The boundary temperature from -25 down to -40°C is achieved by the combined application of fine filter heater, flow-type in-line heater and heated standpipe ÒÏ-301 (302) with increased liquid heating capacity. ÑSpecial application of flexible tape heaters ÝÍÃË-1 is reasonable in case of additional thermal insulation, pre-heating and propulsion heating of conventional external air-cooled fuel pipes. Admissible standards of energy consumption (consumable electric power) for pre-starting and propulsion heating are worked out by practice because of the limited battery life and car generator power capacity. It is considered that pre-heating within 5-10 minutes before engine starting is limited by total electric power consumption up to 250 W for cars and up to 350 W for trucks. In the case of propulsion heating the heaters’ total electrical power should not exceed 200-250 W for vehicles with 12V car-system voltage and 350-400 W for vehicles with 24V car-system voltage. Depending on certain cases energy consumption from car-system up to 500 W is feasible for diesel engines with more than 250-400 kW power at propulsion heating. The noted above standards on electric power consumption should be considered while choosing NOMAKON™ diesel heaters (descriptions with the heating control algorithm selection are given below). Herewith heaters’ power consumption in operating mode describes the tabular index «Nominal electric power, W». Example 1. In order to attain a stable operation boundary temperature equal to -15°C diesel vehicle with 12V car-system voltage is equipped with the fuel heaters represented in the Table 2. The table performs calculations of the total electric power consumption for the pre-starting (170 W) and propulsion heating (220 W).
Example 2. In order to attain a stable operation boundary temperature equal to -40°C diesel vehicle with 24V car-system voltage is equipped with the fuel heaters represented in the Table 3. The table performs calculations of the total electric power consumption for the pre-starting (390 W) and propulsion heating (350 W). As the total pre-heating power more than 350 W, the doubled filter heater ÏÁ-101 (240 W) is switched on first and only then the standpipe heater ÒÏ-301 (150 W).
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