Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/04—Introducing corrections for particular operating conditions
  • F02D41/06—Introducing corrections for particular operating conditions for engine starting or warming up
  • F02D41/062—Introducing corrections for particular operating conditions for engine starting or warming up for starting
  • F02D41/064—Introducing corrections for particular operating conditions for engine starting or warming up for starting at cold start
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/14—Introducing closed-loop corrections
  • F02D41/1497—With detection of the mechanical response of the engine
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/30—Controlling fuel injection
  • F02D41/3011—Controlling fuel injection according to or using specific or several modes of combustion
  • F02D41/3076—Controlling fuel injection according to or using specific or several modes of combustion with special conditions for selecting a mode of combustion, e.g. for starting, for diagnosing

Definitions

• the invention relates to a cold start method of an internal combustion engine for a motor vehicle.
• the invention aims to reduce polluting emissions at the source, gasoline engines.
• the quality of the fuel used for the vehicles is very variable, particularly depending on the geographical area where the vehicle is traveling.
• a particularly variable physical property of fuel is its ability to vaporize, that is, its greater or lesser volatility. This capacity is well known in the Anglo-Saxon literature under the acronym PVR for Steam Pressure Raid. This acronym will be used in the following description of the invention.
• HPVR High PVR
• BPVR Low PVR
• a gasoline engine needs to have a mixture of air and gasoline close to a stoichiometric mixture. This assumes that the amount of fuel in gaseous form is well controlled. However, depending on the volatility of the fuel, the amount of fuel in gaseous form participating in the cold start combustion and the activation of the engine varies enormously for the same amount of fuel injected.
• the calibrations are performed with a fuel representative of a relatively low volatility fuel. Then, checks are made to ensure that when a more volatile fuel is used, the quantities injected are not too large and are unlikely to prevent combustion by excess gasoline in vapor form. The mixture would not be flammable.
• Another method is to measure the time required for the starter to start the engine. This duration can be calibrated according to different types of fuels. As before, the internal friction of the engine affects the time required for the starter to start the engine. There may also be mentioned the battery charge, the position of the clutch and the altitude at which the vehicle is located as parameters influencing the time required for the starter to start the engine.
• the invention aims to propose the measurement of a parameter directly related to the capacity of the fuel used to vaporize, parameter, less sensitive than those previously measured.
• the invention relates to a starting method of an internal combustion engine associated with a starter for driving the engine during its start and means for adapting a quantity of injected fuel, characterized in that during a first starting operation, counting the number of revolutions made by the engine when it is driven by the starter and during a second starting operation, after the first operation, adjusting the quantity of fuel injected according to the number of revolutions counted during the first start operation.
• the count of the number of laps made under starter is considered representative of the volatility of the fuel.
• the invention allows an improvement in the robustness of the start-up benefit, especially during a cold start or even cold weather (outside temperature below -15 0 C). Indeed, it has been realized that the engine can start only when the amount of fuel vaporized in a cylinder is sufficient. Moreover, before the first explosion occurs, the quantities injected accumulate, at least partially, and therefore increase until the amount is sufficient. As a result, the number of engine revolutions made before the first explosion is representative of the volatility of the fuel used.
• Counting the number of turns can be achieved by counting the number of passages of a piston in a cylinder of the engine at top dead center.
• the speed measurement of the engine is performed elsewhere in the vehicle. It is therefore possible to count the number of revolutions made by the engine as long as the engine has not reached a given speed.
• This amount may be a function of a measured engine temperature during the second start operation and / or the engine speed during the second start operation.
• the amount of fuel injected during a start operation can take several discrete values. Each discrete value is associated with a range of revolutions made by the engine when it is driven by the starter, and the value selected is a function of a comparison between the number of revolutions counted and the different ranges.
• the second start operation one can take into account the number of revolutions made by the engine when it is driven by the starter during several first previous startup operations. For example, it is possible to average several starts or eliminate an outlier count.
• Figure 1 shows the evolution of the engine speed during a start operation according to the volatility (PVR) of the fuel used by the engine;
• FIG. 2 illustrates the combination of several parameters involved in an adaptation of the quantity of fuel injected during start-up operations.
• FIG. 1 represents a beam of curves in a coordinate system whose abscissa expresses the number of revolutions made by a motor and whose ordinate expresses the engine speed expressed in revolutions per minute.
• two curves 10 and 1 1 are shown. They each represent the evolution of the engine speed during an engine start operation.
• the fuel used by the engine is of type BPVR (low capacity to vaporize) and for the curve 1 1, the fuel used by the engine is HPVR type (high capacity to vaporize).
• the motor is of alternative type. In a cylinder of the engine, the injection occurs in the vicinity of the moment when a piston moving in the cylinder reaches a top dead center in its course.
• the engine speed is constant during the first eight laps of the engine.
• the value of the regime is of the order of 100 revolutions per minute. This regime corresponds to the moment when the engine is driven by a starter of the vehicle equipped with the engine.
• an explosion occurs in the cylinder considered, the engine speed increases and the starter no longer drives the engine.
• the engine speed increases until reaching a maximum of around 1200 revolutions per minute, on the thirteenth and fourteenth turn then decreases to stabilize from the seventeenth turn at a value of 800 revolutions per minute. This stabilization corresponds to an idle value of the engine.
• the engine speed is constant during the first five laps of the engine. During these five laps, the engine is driven by the starter. At the fifth turn of the engine, an explosion occurs in the cylinder considered, the engine speed increases and the starter no longer drives the engine. Then, the curve 1 1 follows a progression parallel to that of the curve 10, the engine speed increases to reach a maximum, of the order of 1200 revolutions per minute, the tenth and eleventh turn then decreases to stabilize at go from fourteenth round at a value of 800 rounds per minute. This stabilization corresponds to the idle value of the engine.
• Figure 3 illustrates the fact that the amount of fuel to be injected to obtain a proportion close to the stoichiometry when starting the engine is a function of several parameters including the engine temperature and its speed at the start.
• a curve 21 represents a quantity Q1 of fuel to be injected as a function of a temperature ⁇ measured inside the engine.
• a curve 23 represents a correction quantity Q2 to be added to or subtracted from Q1 as a function of the speed of the motor RPM. These two parameters can be defined empirically and are independent of the quality of the fuel used. These two parameters are combined to obtain a quantity Q3 of fuel to be injected as a function of the temperature ⁇ and the speed of the engine RPM. The combination is shown schematically by an operator 24.
• a curve 26 represents a correction amount Q4 of fuel which has been applied during a previous start, as a function of the number of engine PMH revolution of the motor driven by the starter at the start. before last start.
• the curves 21, 23 and 26 shown in the frames 20, 22 and 25 are given only to illustrate the fact that a quantity of fuel can be defined according to a parameter.
• the quantity Q3 is weighted according to this quantity Q4 to obtain a quantity Q of fuel to be injected in order to obtain an optimal start.
• This weighting is schematized by an operator 27.
• the method according to the invention can be implemented in all starting situations or only if the ambient temperature is below a certain temperature threshold, for example less than 10 0 C, or possibly only by large situation. cold.
• the present invention is particularly applicable to spark ignition engines ("gasoline” engines), and more particularly to those of them capable of operating with relatively different fuels, including so-called FLEXFUEL engines, which are powered either with gasoline or with mixtures more or less rich in ethanol or other product of vegetable origin.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
• Combined Controls Of Internal Combustion Engines (AREA)
• Output Control And Ontrol Of Special Type Engine (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=38792520

Family Applications (1)

Country Status (7)

Families Citing this family (8)

Family Cites Families (17)

• 2007
  • 2007-07-09 FR FR0756357A patent/FR2918713B1/fr not_active Expired - Fee Related
• 2008
  • 2008-06-26 JP JP2010515561A patent/JP2010533257A/ja active Pending
  • 2008-06-26 BR BRPI0812664-0A2A patent/BRPI0812664A2/pt not_active Application Discontinuation
  • 2008-06-26 CN CN2008800238493A patent/CN101790630B/zh not_active Expired - Fee Related
  • 2008-06-26 WO PCT/FR2008/051169 patent/WO2009007607A1/fr not_active Ceased
  • 2008-06-26 US US12/668,361 patent/US8141542B2/en not_active Expired - Fee Related
  • 2008-06-26 EP EP08806098A patent/EP2167802A1/de not_active Withdrawn

Non-Patent Citations (2)

Also Published As

Similar Documents

Legal Events