Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D37/00—Non-electrical conjoint control of two or more functions of engines, not otherwise provided for
  • F02D37/02—Non-electrical conjoint control of two or more functions of engines, not otherwise provided for one of the functions being ignition
• • 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
  • F02D41/1401—Introducing closed-loop corrections characterised by the control or regulation method
• • 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
  • F02D2200/00—Input parameters for engine control
  • F02D2200/02—Input parameters for engine control the parameters being related to the engine
  • F02D2200/10—Parameters related to the engine output, e.g. engine torque or engine speed
  • F02D2200/1002—Output torque
  • F02D2200/1004—Estimation of the output torque

Definitions

• the present invention relates to the field of internal combustion engines in which the increase in performance requirements associated with the development of command and control means requires increasingly precise control of the overall operation of these engines.
• the engine control and regulation means can include richness sensors, a motorized intake throttle, an integral electronic ignition, etc.
• knowing the gross engine torque as a function of the applied operating parameters such as richness, speed, air charge and ignition advance, can make it possible to anticipate the command or commands to be used in order to to correctly regulate the operation of the engine taking into account the accessories with which the vehicle is equipped and which must be supplied with energy, directly or indirectly, by the engine such as air conditioning, power steering, an automatic gearbox, a system anti-skid and trajectory control, etc.
• the efficient engine torque at optimal advance is defined as a map depending on the speed and pressure of the manifold. This torque is then increased torque friction through a table according to the regime for the couple said gas which is then corrected by a single advance performance. This gas torque is again reduced by friction losses to finally obtain the effective torque corresponding to the adopted advance setting.
• the object of the present invention is to remedy the drawbacks of the methods proposed above by using a feed efficiency defined in a particularly precise manner.
• the method for estimating the torque of a spark-ignition engine according to the invention is carried out by calculating the average pressure indicated by the positive loop of the pressure cycle in the cylinder as a function of the volume of said cylinder, the positive loop being the part of the curve representative of the operation of the engine when the valves of said engine are closed. This estimate is made as a function of the air flow entering the engine, the pressure in the engine manifold, the operating speed N, the ignition advance AN, and the apparent richness of combustion Ri.
• the indicated average pressure of the positive loop PMI + is equal to the product of the indicated average pressure of the positive loop for a richness equal to 1 and at the optimal advance PMI + t Ri _ 1 , by the richness coefficient ⁇ Ri and by the advance yield ⁇ A ⁇ .
• the richness coefficient ⁇ Ri is equal to 1 if the richness Ri is equal to 1, the richness coefficient ⁇ Ri being a variable dependent on the richness Ri.
• the evolution of PMI + as a function of the advance is modeled by a second degree curve approaching the points actually measured.
• the points actually measured are weighted, a greater weight A being accorded to the measurement points closest to the value of the optimal advance, according to the following equation:
• a (i) A min + ( PMI + (i) - PMI + min ) x (A ma ⁇ - A min ) / (PMI + ma ⁇ - PMI + _ mi in n), 'A mi • _n, being the minimum weight associated with the minimum measured pressure value mean indicated PMI +, A ma ⁇ being the maximum weight associated with the maximum measured value of the mean pressure indicated PMI +, using a minimization criterion: Min [ ⁇ j A (i) 2 x (PMI + (i) mes - PMI-t - (i) calc) 2 ]; i being the number of measurements for a curve, PMI + (i) mes being the average pressure indicated PMI + measured at point i, and PMI + (i) calc being the average pressure indicated PMI-f- calculated at point i according to the modeling
• FIG. 1 shows the pressure curve as a function of the volume of cylinder
• FIG. 2 is a curve showing the evolution of the indicated average pressure of the positive loop as a function of the advance
• FIG. 3 is a similar curve showing the curve obtained without weighting and the curve obtained with weighting
• FIG. 4 is a diagram showing the development of the torque value as a function of the engine speed, the air flow, the manifold pressure, and the ignition advance
• FIG. 5 is an operating diagram of the torque box illustrated in FIG. 4
• Figure 6 is a diagram illustrating the development of the advance yield.
• the evolution of the pressure prevailing in a cylinder of an internal combustion engine with spark ignition as a function of volume is established according to two main loops, a so-called positive loop corresponding to the operation of the engine when the intake and exhaust valves are closed, and a negative loop corresponding to the operation of the engine during the exhaust phase followed by the intake phase, the intake or exhaust valves being open.
• the work which can be recovered in the form of mechanical energy is therefore equal to the indicated average pressure of the positive loop PMI + from which we subtract the indicated average pressure of the negative loop PMI- and the average pressure of PMF friction.
• the richness coefficient ⁇ Ri 1 when the richness Ri is equal to 1.
• the coefficient K is a representative map of the combustion efficiency of the engine at unit richness.
• the advance efficiency ⁇ AV characterizes the change in the indicated average pressure of the positive PMI + loop as a function of the ignition advance.
• This evolution obeys a polynomial regression of the second degree function of the difference between the optimal advance of the operating point and the applied advance and whose curvature is a function of the value of the optimal advance and the richness of operation:
• ⁇ AV 1 - f (ANopt) xh (Ri) x (AV- ANopt) 2 .
• the term AN t is a coefficient established according to a map of optimal advances as a function of the manifold pressure and the operating regime.
• the formulation used to estimate the indicated average pressure of the positive loop PMI + involves the optimal advances ANopt from the various operating points of the engine. All these optimal advances should be able to be precisely characterized. Their determination is mainly carried out in the flattest area of the curve called the advance hat due to its shape. A second degree curve is used to model the evolution of the indicated average pressure of the positive PMI + loop as a function of the advance, its equation being obtained by minimizing the difference between the measured points and the mathematical curve. This type of minimization generates an imprecision of the estimation of the optimal point of advance whereas the value of the optimal PMI + calculated will keep a value close to the measurement. In the example in FIG.
• CRIT (curve) min [b x ⁇ abs (1 - curvature (k) wedge / curvature (k) mes)); k being the number of bending caps.
• CRIT (curve) min [b x ⁇ abs (1 - curvature (k) wedge / curvature (k) mes)); k being the number of bending caps.
• CRIT (ANopt) min [c x ⁇ abs (ANopt (k) mes - AVopt (k) calc)].
• the resulting overall minimization criterion is the algebraic sum of the sub-criteria defined above.
• a multiplicative weight of the precision objective that is desired is assigned (the coefficients a, b and c).
• the torque value is developed from the average pressure exerted PME in the engine; the value of the average pressure exerted being obtained from the exhaust pressure and from the outputs of a torque box whose operation is illustrated in FIG. 5, and from the engine speed N.
• the exhaust pressure is calculated from the amount of air entering the engine Q r expressed in kilograms / second.
• the torque box makes it possible to obtain the values of the manifold pressure P j , of the indicated average pressure of the positive loop PMI +, of the advance efficiency ⁇ AV , of the richness coefficient ⁇ Ri and the mean PMF operating pressure of the engine.
• the value of the PMI + is obtained as explained above by a weighting taking into account the values of the quantity of air entering the engine Q r in grams per revolution, from a mapping of the coefficient K as a function of the manifold pressure P co] and of the operating regime N with unit richness, of the advance efficiency ⁇ A and of the richness coefficient ⁇ Rj .
• Obtaining the value of the advance yield ⁇ AV is illustrated in FIG. 6.
• the representative richness coefficient ⁇ Ri curve is obtained from the value of the richness Ri.
• the average operating pressure PMF is calculated from the operating speed N.
• the quantity of air Q r in grams per revolution is calculated from the quantity of air in kg / s and the operating speed N.
• the yield of advance ⁇ AV is worked out starting from the influence of the richness on the curvatures of the caps modeled h (Ri), of the advance AV, of the table of curvatures hats modeled f (AVopt) and optimal advances AVopt (Ri).
• the function h (Ri) is developed from the value of the richness Ri.
• the calculation of the table of curvatures of the caps modeled f (AVopt) and of the optimal advances AVopt (Ri) is carried out from the maps established for a unit richness and for a richness less than 1, for example equal to 0.68, in function of the operating regime N and of the manifold pressure P col , and of the variable P depending on the richness Ri.

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

Applications Claiming Priority (3)

Publications (2)

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Family Applications (1)

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• 1998
  • 1998-03-12 FR FR9803068A patent/FR2776066B1/fr not_active Expired - Fee Related
• 1999
  • 1999-03-12 JP JP2000535839A patent/JP4299460B2/ja not_active Expired - Fee Related
  • 1999-03-12 DE DE69901547T patent/DE69901547T2/de not_active Expired - Lifetime
  • 1999-03-12 WO PCT/FR1999/000554 patent/WO1999046497A1/fr active IP Right Grant
  • 1999-03-12 EP EP99907695A patent/EP1062416B1/de not_active Expired - Lifetime

Non-Patent Citations (1)

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