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CN-116761937-B - Cleaning device and method for a hydrocarbon vapor-filled gas flow

CN116761937BCN 116761937 BCN116761937 BCN 116761937BCN-116761937-B

Abstract

A cleaning device (10) of fuel vapors stored in a fuel tank (30) of a thermodynamic motor vehicle (1), comprising a control module (130) configured in particular to determine a contribution of convection of a gas flow to a temperature of the gas flow based on a received gas flow temperature measurement and a received pump internal temperature measurement, to determine a contribution of conduction of the gas flow to the gas flow temperature based on a mass flow of the gas flow, the received gas flow temperature and the received pump internal temperature measurement, to estimate a temperature of the gas flow flowing in a cleaning circuit (120) based on the determined adiabatic compression, convection and conduction contributions, and to calculate a fuel vapor concentration of the gas flow based on the estimated temperature.

Inventors

  • A. Grussad
  • KOLLETH TOBIAS
  • B. Ehalk

Assignees

  • 纬湃科技有限责任公司

Dates

Publication Date
20260505
Application Date
20220121
Priority Date
20210128

Claims (8)

  1. 1. A cleaning device (10) of fuel vapors stored in a fuel tank of a hybrid or thermo-dynamic motor vehicle (1), said vehicle (1) comprising a heat engine (20) and a fuel tank (30) for storing fuel to be combusted in said engine (20), said device comprising: an absorption filter (110) capable of filtering vapors in the form of hydrocarbons produced by the fuel stored in the fuel tank (30), -A purge circuit (120) connected to the absorption filter and intended to be connected to the engine (20), and comprising: A pump (121) that enables the flow of the hydrocarbon vapor-containing gas stream of the absorption filter (110) to the engine (20), The pressure sensor arranged upstream of the pump (121), referred to as "upstream pressure sensor (122)", The pressure sensor arranged downstream of the pump (121), referred to as "downstream pressure sensor (123)", A flow temperature sensor (124) configured to measure a temperature of the gas flow, A purge valve (125) configured to switch between an open position, in which the purge valve enables airflow of the absorption filter (110) to flow to the engine (20), and a closed position, in which the absorption filter (110) is isolated from the engine (20), -A control module (130) configured in a cleaning mode to: receives measurements from an upstream pressure sensor (122) and a downstream pressure sensor (123), A differential pressure of the air flow between the input and the output of the pump (121) is calculated based on the received upstream and downstream pressure measurements, Receives temperature measurements from a flow temperature sensor (124), rotational speed of the pump (121) and internal temperature of the pump (121), Determining the mass flow of the air stream based on the received rotational speed of the pump (121), Determining a contribution T Flow_Adb of adiabatic compression of the gas stream to the temperature of the gas stream based on the calculated differential pressure and the received temperature measurement of the gas stream according to: where T Inlet is the gas flow temperature received from the flow temperature sensor, P Flow is the gas flow pressure received from the downstream pressure sensor (123), P Inlet is the gas flow pressure measured by the upstream pressure sensor (122), and γ is the ideal gas constant, Determining the contribution of convection of the air flow to the temperature of the air flow based on the received temperature measurement of the air flow and the received measurement of the internal temperature of the pump (121) according to the formula: Wherein HeatFac Conv is the magnitude used to represent the heat exchange between the material of the pump (121) and the gas stream by convection and radiation, T Body is the internal temperature of the pump (121), and T Inlet is the gas stream temperature measured by the stream temperature sensor (124), Determining a contribution of conduction of the gas flow to the gas flow temperature based on the determined mass flow rate of the gas flow, the received temperature of the gas flow, and the received measurement of the internal temperature of the pump (121) according to the formula: Wherein, the Is the mass flow of the air flow through the pump (121), heatFac Cond is the amount of heat exchange by conduction between the material of the pump (121) and the air flow, T Body is the internal temperature of the pump (121), and T Inlet is the air flow temperature measured by the flow temperature sensor (124), Estimating the temperature of the gas stream flowing in the cleaning circuit based on the determined adiabatic compression, convection and conduction contributions according to the following formula: The fuel vapor concentration of the gas stream is calculated based on the estimated temperature, the received pressure measurement and the received rotational speed of the pump, A purge valve (125) is operated to control the flow of air into a cylinder of the engine (20) in accordance with the calculated concentration while following a combustion stoichiometry of an air-fuel mixture with respect to the cylinder.
  2. 2. The device (10) of claim 1, wherein the control module (130) is configured to determine a moment when purging of the fuel vapor is completed, close the purge valve (125), and operate the pump (121) such that the pump (121) operates in the non-purge mode at a predetermined minimum rotational speed.
  3. 3. The apparatus (10) of claim 1 or 2, wherein the control module (130) is configured to calculate the fuel vapor concentration of the gas stream based on the estimated temperature according to: Where ρ gas is the density of the gas in the pump (121), ρ air is the density of air at pressure and temperature in the pump (121), and ρ but is the density of butane at pressure and temperature in the pump (121).
  4. 4. Motor vehicle comprising a device (10) according to any one of claims 1 to 3, a heat engine (20) comprising at least one cylinder, and a fuel tank (30) for storing fuel to be combusted in the at least one cylinder of the engine (20).
  5. 5. A method for controlling the flow rate of an air flow flowing in a cleaning device (10) according to any one of claims 1 to 3, the method being implemented by a control module (130) of the device and comprising the steps of: receiving (E1) at least one measurement of the pressure of the gas flow upstream of the pump (121), Receiving (E2) at least one measurement of the pressure of the gas stream downstream of the pump (121), -Calculating (E3) a pressure difference of the air flow between the input and the output of the pump (121), Receiving (E4) at least one temperature measurement from a flow temperature sensor (124), Receiving (E5) at least one measurement of the rotational speed of the pump (121) and the internal temperature of the pump (121), Determining (E6) the mass flow of the air flow based on the received rotational speed of the pump (121), -Determining (E7) the contribution T Flow_Adb of adiabatic compression of the gas flow to the temperature of the gas flow based on the calculated pressure difference and the received temperature measurement of the gas flow according to: where T Inlet is the gas flow temperature received from the flow temperature sensor, P Flow is the gas flow pressure received from the downstream pressure sensor, P Inlet is the gas flow pressure measured by the upstream pressure sensor (122), and γ is the ideal gas constant, -Determining (E8) a contribution of convection of the air flow to the temperature of the air flow based on the received temperature measurement of the air flow and the received measurement of the internal temperature of the pump according to the following formula: Wherein HeatFac Conv is the magnitude used to represent the heat exchange between the material of the pump (121) and the gas stream by convection and radiation, T Body is the internal temperature of the pump (121), and T Inlet is the gas stream temperature measured by the stream temperature sensor (124), -Determining (E9) a contribution of conduction of the gas flow to the gas flow temperature based on the determined mass flow of the gas flow, the received temperature of the gas flow and the received measurement of the internal temperature of the pump according to the formula: Wherein, the Is the mass flow of the air flow through the pump (121), heatFac Cond is the amount of heat exchange by conduction between the material of the pump (121) and the air flow, T Body is the internal temperature of the pump (121), and T Inlet is the air flow temperature measured by the flow temperature sensor (124), -Estimating (E10) the temperature of the gas flow flowing in the cleaning circuit based on the determined adiabatic compression, convection and conduction contributions according to the following formula: Calculating (E11) the fuel vapor concentration of the gas flow based on the estimated temperature, -Actuating (E12) a purge valve to control the flow of air into the cylinder of the engine (20) according to the calculated concentration, following the combustion stoichiometry of the air-fuel mixture with respect to said cylinder.
  6. 6. The method of claim 5, further comprising the step of the control module performing the steps of determining (E13) a moment when purging of fuel vapor is completed, closing (E14) the purge valve (125), and manipulating (E15) the pump (121) such that the pump (121) operates in a non-purge mode at a predetermined minimum rotational speed.
  7. 7. The method of claim 5 or 6, wherein the fuel vapor concentration of the gas stream is calculated based on the estimated temperature according to the following formula: Where ρ gas is the density of the gas in the pump (121), ρ air is the density of air at pressure and temperature in the pump (121), and ρ but is the density of butane at pressure and temperature in the pump (121).
  8. 8. Computer program product, characterized in that it comprises a set of program code instructions which, when executed by one or more processors, configure the one or more processors to implement the method according to any one of claims 5 to 7.

Description

Cleaning device and method for a hydrocarbon vapor-filled gas flow Technical Field The present invention relates to the treatment of hydrocarbon vapors (vapeur d' hydrocarbure) in motor vehicles, and more particularly to a purge device of hydrocarbon vapors in heat engines of motor vehicles. The invention has particular application to hybrid vehicles and purely heat engine vehicles. Throughout, the term "fuel" advantageously relates to at least one hydrocarbon. Background In motor vehicles equipped with heat engines, the fuel stored in the fuel tank needs to be in contact with the external air, which makes it possible to discharge the vapors emitted by the fuel and to let the air enter the fuel tank when the fuel level is reduced. Thus, it is necessary to regulate the pressure of the gas contained in the fuel tank so as not to vary too much, which may cause physical and personal hazards. For this purpose, a known solution is to form a vent in the closure of the fuel tank in order to discharge these hydrocarbon vapors directly to the outside of the vehicle, while letting air into the fuel tank in order to equalize the pressure. The main disadvantage of these hydrocarbon vapors emissions to the atmosphere is the severe environmental pollution. However, given the various regulations becoming more stringent in this regard, and some of them require strict limits to the emission of hydrocarbon vapors into the atmosphere, such emissions are now becoming increasingly undesirable and infeasible. In addition, in order to limit pollution, it is currently known to install a filter device in the fuel intake system of a vehicle. Such devices are connected on one side to the fuel tank and on the other side to the outside of the vehicle. In known solutions, the device comprises a decarbonizing filter, hereinafter called "absorption filter" (commonly known to the person skilled in the art as "canister (gasoline vapor absorption tank)" in the english language), which enables the absorption of hydrocarbon vapors from the fuel tank, so that the fuel emissions discharged by the emission device into the atmosphere are in the form of gases which are substantially purified of the polluting components contained in the hydrocarbon vapors. However, such an absorption filter has a limited absorption capacity, i.e. the maximum load of the filter. Thus, the absorption filter is said to be "full" or "filled", or it is said to be saturated. In this case, the filter is no longer able to retain hydrocarbon vapors, so that hydrocarbon vapors escape to the atmosphere. More generally, whether or not the absorption filter is saturated, it has at a given moment a specific load characteristic, said load corresponding to the mass percentage of fuel stored in said filter with respect to its saturation value (i.e. with respect to its maximum load). To limit the detrimental release of fuel into the atmosphere when the filter is saturated, the filter needs to be cleaned periodically, preferably before the filter is saturated with hydrocarbon vapor. For this purpose, the device is connected to the heat engine of the vehicle in order to enable the hydrocarbon vapors absorbed by the filter to be injected directly into the combustion chamber of the engine cylinder during operation of the engine, so that they are combusted. In other words, the absorption filter is periodically filled with hydrocarbon vapors from the fuel tank, and then the engine control computer intermittently unloads the load of the absorption filter into the combustion chamber of the cylinder of the heat engine while said engine is operating. The transport of hydrocarbon vapors in the filter to the heat engine takes place in a purge circuit via a purge valve that enables the purge circuit to be placed under vacuum. However, with the advent of hybrid vehicle technology, it has become increasingly difficult to purge the filter of hydrocarbon vapors because in hybrid vehicles it is more difficult to put the purge circuit under vacuum. In fact, in hybrid vehicles, it is preferable to use the heat engine when high rotational speeds are required. At high speeds, however, the intake throttle is open, which reduces the low pressure in the purge circuit. Moreover, due to this mode of operation, the heat engine is operated for less and less time available to perform cleaning, which may result in hydrocarbon vapors being vented to the atmosphere, as the filter is more often saturated in the event of a failure to clean. Known solutions for solving this problem include the use of a radial pump, called active purge pump, between the filter and the engine in order to flow hydrocarbon vapors in the purge circuit to the engine. In this way, the amount of hydrocarbon vapor introduced into the engine cylinders needs to be compensated with a corresponding volume of air to follow the stoichiometric air-fuel ratio required for good combustion of the mixture in the heat engine. In existing solutions, it is kn