JP2006170114A - Engine gas flow detection device - Google Patents

Abstract

An apparatus for calculating (detecting) the strength of gas flow in a combustion chamber with a simple configuration using an existing sensor without providing a special sensor.
An intake valve (15) that opens and closes the combustion chamber (5) at an opening of the intake port (4) to the combustion chamber (5), and the intake valve (15) opens the combustion chamber (5). In an engine comprising a piston (6) that descends when open and draws air from the intake port (4) into the combustion chamber (5), the intake valve (15) during the open period of the intake valve (15) Means (31) for calculating the strength of gas flow generated in the combustion chamber (5) by the intake valve passage fluid flowing into the combustion chamber (5) and the combustion chamber (5) by the behavior of the piston (6). 5) A means (31) for calculating the strength of the gas flow generated in the inside, and a means (31) for calculating the strength of the gas flow in the combustion chamber (5) based on at least one of the strengths of the gas flow. ).
[Selection] Figure 1

Description

  The present invention relates to an engine gas flow detection device.

There is one that calculates the actual gas flow U in the combustion chamber based on the average discharge resistance rs calculated by the discharge resistance calculation means and the discharge time Ds determined by the discharge time determination means (see Patent Document 1). .
Japanese Unexamined Patent Publication No. 60-198347

  By the way, the behavior of fluid such as swirl, tumble and turbulence generated in the combustion chamber is the gas flow in the combustion chamber, and the combustion speed of the air-fuel mixture changes due to the difference in the gas flow in the combustion chamber. Therefore, there is a demand for an apparatus that can detect the strength of gas flow in the combustion chamber with a simple configuration without providing a special sensor.

  However, the technique of Patent Document 1 is expensive because a dedicated circuit is required as the discharge resistance calculation means and the discharge time determination means. In particular, it is difficult to accurately detect the ignition discharge time and the discharge resistance. If an error occurs in the detection of the ignition discharge time and the discharge resistance, the detection error directly becomes a detection error of the gas flow strength in the combustion chamber. End up.

  Accordingly, an object of the present invention is to provide a device that calculates (detects) the strength of gas flow in a combustion chamber with a simple configuration using an existing sensor without providing a special sensor.

  The present invention relates to an intake valve that opens and closes a combustion chamber at an opening of the intake port to the combustion chamber, and descends when the intake valve opens the combustion chamber to allow air to flow from the intake port to the combustion chamber. And the piston to be sucked in, and calculates the strength of the gas flow generated in the combustion chamber by the intake valve passage fluid that passes through the intake valve and flows into the combustion chamber during the opening period of the intake valve, The strength of the gas flow generated in the combustion chamber is calculated based on the above behavior, and the strength of the gas flow in the combustion chamber is calculated based on at least one of the strengths of the gas flow.

  The present invention also relates to an intake valve that opens and closes the combustion chamber at the opening of the intake port to the combustion chamber, and descends when the intake valve opens the combustion chamber to allow air to flow from the intake port to the combustion chamber. In an engine including a piston that is sucked into a chamber, based on at least one of four parameters of a pressure ratio before and after the intake valve, an opening area of the intake valve, a density of the fluid passing through the intake valve, and the piston speed And calculating the strength of the gas flow in the combustion chamber.

  The present invention also relates to an intake valve that opens and closes the combustion chamber at the opening of the intake port to the combustion chamber, and descends when the intake valve opens the combustion chamber to allow air to flow from the intake port to the combustion chamber. In an engine including a piston that is sucked into a chamber, based on at least one of four parameters of a pressure ratio before and after the intake valve, an opening area of the intake valve, a density of the fluid passing through the intake valve, and an engine rotation speed And calculating the strength of the gas flow in the combustion chamber.

  According to the present invention, the strength of the gas flow generated in the combustion chamber by the intake valve passage fluid flowing through the intake valve and flowing into the combustion chamber when the intake valve is open is calculated, and the combustion chamber is calculated by the behavior of the piston. Or the pressure ratio before and after the intake valve, the opening of the intake valve, and the intensity of the gas flow in the combustion chamber is calculated based on at least one of these gas flow strengths. Calculate the strength of gas flow in the combustion chamber based on at least one of the following parameters: area, density of intake valve passage fluid density or piston speed, or pressure ratio before and after the intake valve, intake valve opening area, Since the strength of gas flow in the combustion chamber is calculated based on at least one of the four parameters of the density of the intake valve passage fluid or the engine speed, a special sensor is used. It not, it is possible to obtain the intensity of the combustion chamber of a gas flow with a simple configuration using the existing sensor.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram for explaining a system according to an embodiment of the present invention applied to an L-Jetronic gasoline injection engine.

  The air metered by the intake throttle valve 23 is stored in the intake collector 2 and then introduced into the combustion chamber 5 of each cylinder via the intake manifold 3. Fuel is intermittently injected and supplied into the intake port at a predetermined timing from a fuel injection valve 21 disposed in the intake port 4 of each cylinder. The fuel injected into the intake port 4 is mixed with air to form an air-fuel mixture. The air-fuel mixture is confined in the combustion chamber 5 by closing the intake valve 15, compressed by the ascending piston 6, and the spark plug 14 It is ignited and burns. The gas pressure due to the combustion works to push down the piston 6, and the reciprocating motion of the piston 6 is converted into the rotational motion of the crankshaft 7. The combusted gas (exhaust gas) is discharged into the exhaust passage 8 when the exhaust valve 16 is opened.

The exhaust passage 8 includes three-way catalysts 9 and 10. The three-way catalysts 9, 10 can efficiently remove HC, CO and NOx contained in the exhaust gas simultaneously when the air-fuel ratio of the exhaust gas is in a narrow range centered on the stoichiometric air-fuel ratio. For this reason, the engine controller 31 determines the basic fuel injection amount from the fuel injection valve 21 according to the operating conditions, and feedback controls the air-fuel ratio based on the signal from the O ₂ sensor 35 provided upstream of the three-way catalyst 9. To do.

  The intake throttle valve 23 is driven by a throttle motor 24. Since the torque required by the driver appears in the amount of depression of the accelerator pedal 41 (accelerator opening), the engine controller 31 determines a target torque based on a signal from the accelerator sensor 42, and a target air for realizing this target torque. The amount is determined, and the opening degree of the intake throttle valve 23 is controlled via the throttle motor 24 so that this target air amount is obtained.

  A variable valve lift mechanism (hereinafter referred to as “VEL mechanism”) 26 constituted by a multi-node link mechanism for continuously and variably controlling the valve lift amount of the intake valve 15, the crankshaft 7, and the intake valve cam. A variable valve timing mechanism (hereinafter referred to as “VTC mechanism”) 27 is provided that continuously and variably controls the rotational phase difference with the shaft 25 to advance or retard the opening / closing timing of the intake valve 15. Since these specific configurations are known from Japanese Patent Laid-Open No. 2003-3872, detailed description thereof is omitted. For example, when the command value is not given to both the VEL mechanism 26 and the VTC mechanism 27, the valve lift of the intake valve 15 is a characteristic that responds to the output request, and has a large valve lift amount and a large operating angle substantially equivalent to those of the exhaust valve 16. Have. On the other hand, when the command value is given only to the VEL mechanism 26, both the valve lift amount and the operating angle are reduced without changing the crank angle position at which the valve lift becomes maximum. Further, when the command value is not given to the VTC mechanism 27, the rotation phase is at the most retarded angle position, and when the command value is given only to the VTC mechanism 27, the rotation phase is changed without changing the valve lift amount and the operating angle. Specifically, only the intake valve opening timing IVO (or the intake valve closing timing IVC) moves to the advance side.

  On the premise of an engine having such a variable valve system comprising a VEL mechanism 26 and a VTC mechanism 27, the engine controller 31 passes through the intake valve 15 and flows into the combustion chamber 5 while the intake valve 15 is open. The strength of the gas flow generated in the combustion chamber 5 by the passing fluid and the strength of the gas flow generated in the combustion chamber 5 by the behavior of the piston 6 are calculated, and the inside of the combustion chamber 5 is calculated based on these two gas flow strengths. The strength of gas flow is calculated.

  In this case, it is not handled by the gas flow intensity itself, but by an index which is a number such as 5 or 10 levels. Specifically, the strength of the gas flow generated in the combustion chamber 5 by the intake valve passage fluid flowing through the intake valve 15 and flowing into the combustion chamber 5 during the opening period of the intake valve 15 is represented by an intake flow index IND1. The strength of the gas flow generated in the combustion chamber 5 due to the behavior of the piston 6 is represented by a piston behavior flow index IND2, and the strength of the gas flow in the combustion chamber 5 is represented by a combustion chamber flow index IND3. Here, the intake valve passage fluid is an air-fuel mixture.

  The intake flow index IND1 is calculated based on the kinetic energy U of the intake valve passage fluid, and the piston behavior flow index IND2 is calculated based on the average piston speed ΔST.

  A method of calculating (detecting) the three indexes IND1, IND2, and IND3 executed by the engine controller 31 will be described with reference to the control block diagram of FIG.

  In FIG. 2, the combustion chamber instantaneous pressure calculation unit 51 calculates the instantaneous pressure Pc [Pa] of the combustion chamber 5. This will be described in detail with reference to FIG. 3, but before that, the concept for calculating the instantaneous pressure in the combustion chamber 5 will be described.

  The instantaneous air flow rate Uj [g / msec] flowing into the combustion chamber 5 can be obtained by the following equation.

Uj = Aij × Pp × [{κ / (1-κ)} × {2 / (R × Tp)}
× {(Pc / Pp) ^ (2 / κ)
-(Pc / Pp) ^ ((κ + 1) / κ)}] ^ (1/2)
... (1)
However, Aij: Instantaneous opening area of intake valve [m ² ],
Pp: instantaneous pressure [Pa] at the intake port 4;
Pc: instantaneous pressure [Pa] in the combustion chamber 5;
Tp: air temperature [K] of the intake port 4;
R: gas constant,
κ: specific heat ratio,
The expression (1) is a modification of the Bernoulli expression to an expression that handles the passage of the orifice, and the pressure ratio (Pc / Pp) before and after the intake valve 15 is used.

  In this case, there are four variables of equation (1), Aij, Pp, Pc, and Tp, and Aij is determined from the specifications of the variable valve mechanism and the crank angle. The instantaneous pressure Pp of the intake port 4 may be detected by a pressure sensor 36 attached to the intake collector 2, and the air temperature Tp of the intake port 4 may be detected by a temperature sensor 37 attached to the intake port 4. The air temperature Tp of the intake port 4 may be simply replaced with the outside air temperature.

  Here, in the above equation (1), the subscript “j” is added to the instantaneous opening area Aij of the intake valve 15 because the instantaneous opening area Ai is inhaled from the intake valve opening timing IVO as shown in the lower part of FIG. Since the crank angle section until the valve closing timing IVC changes greatly, the crank angle section where the intake valve 15 is open is divided into n equal parts (n is a natural number of 2 or more) for each predetermined crank angle Δθ. The angles are θ1, θ2,..., Θj,..., Θn, and the instantaneous opening area at each boundary crank angle (predetermined timing) is distinguished as Ai1, Ai2,. “Instantaneous” means a value at each boundary crank angle.

  Since the air amount of Uj × Δt flows into the combustion chamber per calculation cycle Δt [msec], the gas mass Wc [g] in the combustion chamber 5 can be calculated by the following equation.

Wc = Wc (previous) + Uj × Δt (2)
Where Wc (previous); previous value of Wc,
Here, the mass of gas in the combustion chamber 5 when the exhaust valve 16 is closed is used as the initial value of Wc. This corresponds to the determination of the gas mass in the combustion chamber 5 when the exhaust valve 16 is closed.

Further, the instantaneous volume Vc [m ³ ] at the boundary crank angle θj of the combustion chamber 5 can be calculated by the following equation.

Vc = Vc (previous) + ΔST × Ac (3)
Where ΔST: average piston speed [m / msec],
Ac: Piston crown area [m ² ],
Vc (previous); previous value of Vc,
Equation (3) is for obtaining the instantaneous volume of the combustion chamber 5 that increases as the piston 6 descends from the top dead center.

  Here, as the initial value of Vc, the combustion chamber volume when the exhaust valve 16 is closed is used as in the case of Wc described above.

  From the instantaneous volume Vc of the combustion chamber 5 obtained from the above equations (2) and (3) and the gas mass Wc in the combustion chamber 5, the instantaneous pressure Pc [Pa] at the boundary crank angle θj of the combustion chamber 5 is expressed by the following equation. Can be calculated.

Pc = Wc / Vc (4)
Thus, according to the equations (2) to (4), the instantaneous pressure Pc of the combustion chamber 5 is obtained based on the instantaneous flow rate Uj of the combustion chamber inflow, and according to the above equation (1), the instantaneous pressure of the combustion chamber 5 is obtained. Using Pc, the combustion chamber inflow instantaneous air amount Uj is obtained. In other words, Uj and Pc are in a relationship in which one is used to obtain the other, so Uj and Pc cannot be obtained at the same timing. Accordingly, each boundary crank angle θj is used as a calculation timing, and Uj and Pc are calculated discretely. For example, at the timing j = 1, the combustion chamber inflow instantaneous air amount Uj (= U1) at the timing j = 1 is calculated by the above equation (1) using Pc at the exhaust valve closing timing EVC, and the calculated Uj Is used to calculate the instantaneous pressure Pc of the combustion chamber 5 from the equations (2) to (4). Pc at the timing of j = 1 is stored, Uj (= U2) at the timing of j = 2 is calculated using the stored Pc at the timing of j = 2, and the calculated Uj is calculated. To calculate Pc. The Pc obtained at the timing of j = 2 is stored, and Uj (= U3) at the timing of j = 3 is calculated using the stored Pc at the timing of j = 3. Pc is calculated using Uj. In this way, Uj at the current timing is calculated using Pc obtained at the previous timing.

  This concludes the description of the concept for calculating the instantaneous pressure in the combustion chamber, and details the flowchart of FIG.

  FIG. 3 shows the processing in time series and is not executed at regular intervals. FIG. 3 shows the process for one cylinder. In a multi-cylinder engine, the process of FIG. 3 is performed for each cylinder.

  In FIG. 3, in step 1, it is determined whether or not the current crank angle θ detected by the crank angle sensor (33, 34) has passed the intake valve opening timing IVO (including the case where it is IVO). If the current crank angle θ has not passed IVO, the process ends as it is.

  When the current crank angle θ has passed IVO, the process proceeds to step 2 to check whether or not the current crank angle θ matches the boundary crank angle θj. Here, θj is specifically one of θ1, θ2,..., Θn shown in FIG. When the current crank angle θ is none of these boundary crank angles θ1, θ2,..., Θn, the current process is terminated as it is.

  When the current crank angle θ coincides with the boundary crank angle θj, the routine proceeds to step 3 where the instantaneous pressure Pp of the intake port 4 detected by the pressure sensor 36 and the air temperature Tp of the intake port 4 detected by the temperature sensor 37 are read.

  In step 4, the instantaneous opening area Aij of the intake valve 15 is calculated by searching a table having the lower part of FIG. 4 from the boundary crank angle θj. The characteristics of the instantaneous opening area of the intake valve 15 are uniquely determined by the engine specification for an engine not provided with a variable valve device, and by the specification of the variable valve device for an engine provided with a variable valve device. For example, in an engine having a variable valve system, if the characteristics of the intake valve 15 are switched between a characteristic having a normal lift amount and an operating angle and a characteristic having both a lift amount and an operating angle smaller than these, these two cases Two types of tables may be prepared corresponding to the above, and either one may be selected and used.

  In step 5, in addition to the instantaneous pressure Pp of the intake port 4 read in step 3, the air temperature Tp of the intake port 4, the instantaneous opening area Aij of the intake valve 15 calculated in step 4, the boundary crank angle θj of the combustion chamber 5 Using the instantaneous pressure Pc, the combustion chamber inflow instantaneous air flow rate Uj (= U1) is calculated by the above equation (1).

   Here, the instantaneous pressure Pc of the combustion chamber 5 used for calculating the instantaneous air flow rate Uj at the boundary crank angle θ1 is the pressure in the combustion chamber 5 when the exhaust valve 16 is closed. Since this is equal to the exhaust pressure immediately before the exhaust valve 16 is closed, the exhaust pressure Pexh at the exhaust valve closing timing EVC detected by the pressure sensor 38 is used. On the other hand, after the boundary crank angle θ2, the instantaneous pressure Pc of the combustion chamber 5 used in the expression (1) is estimated in steps 8 to 10 as described later.

  Steps 6 to 8 are parts for calculating (estimating) the pressure Pc at the boundary crank angle θj of the combustion chamber 5. First, in step 6, the gas mass Wc in the combustion chamber 5 is calculated by the above equation (2). Here, the initial value of Wc is the gas mass at the exhaust valve closing timing EVC, and for example, the internal inert gas amount MRES is used as the initial value of Wc. A known method may be used to calculate the internal inert gas amount MRES.

  In step 7, the instantaneous volume Vc at the boundary crank angle θj of the combustion chamber 5 is calculated by the above equation (3). Here, the initial value of Vc is the volume of the combustion chamber 5 at the exhaust valve closing timing EVC, which is determined by the specifications of the engine. The average piston speed ΔST is a distance traveled by the piston 6 per calculation cycle. Since the average piston speed ΔST is proportional to the engine rotation speed, it may be calculated by searching a table having the contents shown in FIG. 5 from the engine rotation speed.

  In step 8, the instantaneous pressure Pc at the boundary crank angle θj of the combustion chamber 5 is calculated from the above equation (4) from the instantaneous volume Vc of the combustion chamber 5 and the gas mass Wc in the combustion chamber 5.

  In step 9, in order to obtain the next boundary crank angle θj, θj = θj + Δθ is set, and j is incremented by 1 (j = j + 1).

  In step 10, j after addition is compared with n which is the total number of samples. As the total number n of samples increases, the calculation accuracy of the instantaneous pressure Pc in the combustion chamber 5 improves. However, since the calculation load increases, the total number n is determined by adaptation. Since j is smaller than n at the timing when the operation of step 9 is performed for the first time, the process returns to step 2 to check whether or not the current crank angle θ matches the boundary crank angle θj. When they coincide with each other, the operations in steps 3 to 5 are executed to determine the combustion chamber inflow instantaneous air flow rate Uj at the next boundary crank angle θj. In this case, the instantaneous pressure Pc used in the above equation (1) in step 5 is the instantaneous pressure Pc calculated in step 8 last time. In steps 6-8, the instantaneous pressure Pc at the boundary crank angle θj of the combustion chamber 5 that is required next time is calculated.

  In step 9, θj = θj + Δθ and j = j + 1 are set again, and in step 10, j and n are compared. At this time, since j is smaller than n, the process returns to Step 2 and if the current crank angle θ matches the boundary crank angle θj, the operations of Steps 3 to 10 are repeated.

  In this way, the operations in steps 2 to 10 are repeated n-1 times. When the operations in steps 2 to 10 are performed n-1 times, the process proceeds from step 10 to step 11 to initialize θj, j, Wc, Vc, and Pc in preparation for the next cycle.

  This is the end of the description of the calculation of the instantaneous pressure Pc in the combustion chamber 5, and the description returns to FIG. The present invention is not limited to the case where the instantaneous pressure Pc of the combustion chamber 5 is calculated, and the instantaneous pressure of the combustion chamber 5 may be directly detected by a pressure sensor.

  In FIG. 2, the intake valve front-rear pressure ratio calculation unit 52 calculates the pressure ratio before and after the intake valve 15 from the instantaneous pressure Pc [Pa] of the combustion chamber 5 and the instantaneous pressure Pp [Pa] of the port detected by the pressure sensor 36. Pc / Pp is calculated, and the intake valve passage instantaneous flow velocity calculation unit 53 calculates the pressure ratio Pc / Pp before and after the intake valve 15 and the air temperature Tp [K] of the intake port 4 detected by the temperature sensor 37. Then, the intake valve passage instantaneous flow velocity Vi [m / msec] is calculated by the following equation.

Vi = [{κ / (κ−1)} × {2 / (R × Tp)}
× {(Pc / Pp) ^ (2 / κ)
-(Pc / Pp) ^ ((κ + 1) / κ)}] ^ (1/2)
... (5)
Where R is the gas constant,
κ: specific heat ratio,
The right side of the equation (5) is the same as the equation obtained by removing Aij and Pp from the right side of the above equation (1), and the pressure ratio Pc / Pp before and after the intake valve 15 is used when obtaining the intake valve passage instantaneous flow velocity Vi. ing. The air temperature Tp of the intake port 4 may be simply replaced with the outside air temperature.

The intake valve passage instantaneous mass flow rate calculation unit 54 calculates the intake valve passage instantaneous mass flow rate Cc from the intake valve passage instantaneous flow rate Vi, the intake valve opening area Ain [m ² ], and the fresh air density ρ [g / m ³ ] by the following equation. [G / msec] is calculated.

Cc = Vi / (Ain × ρ) (6)
Here, the intake valve opening area Ain is different from the instantaneous opening area Aij used for calculating the combustion chamber inflow instantaneous air flow rate, and the intake valve opening area between the intake valve opening timing IVO and the intake valve closing timing IVC. The average value and effective opening area are adopted. In detail, in an engine having a variable valve system, for example, as shown in FIG. 6, it is determined whether to use a small lift or a large lift depending on the operating conditions. The value Ainav1 may be used, and the opening area average value Ainav2 shown in the figure may be used under the operating conditions of the large lift.

  Strictly speaking, the fluid passing through the intake valve also includes a residual gas component that flows back from the combustion chamber 5 to the port 4, but here, the residual gas component is ignored and the density ρ of the fresh air is set. adopt. As the fresh air density ρ, the density of air in a standard state (20 ° C., one atmospheric pressure) is stored in advance in a memory.

  The intake valve passage fluid kinetic energy calculation unit 55 calculates the kinetic energy U [J] of the intake valve passage fluid from the intake valve passage instantaneous flow velocity Vi and the intake valve passage instantaneous mass flow rate Cc according to the following equation.

U = Const × (1/2) × Cc × Vi ^ 2 (7)
Where Const; constant 1,
The constant 1 Const in the equation (7) is a numerical value for unit alignment.

  The intake flow index calculation unit 56 calculates the intake flow index IND1 [anonymous number] from the kinetic energy U of the intake valve passage fluid thus obtained by the following equation.

IND1 = U × factor 1 (8)
On the other hand, the average piston speed calculation unit 57 calculates the average piston speed ΔST [m / msec] by the following formula.

ΔST = stroke × 2 / {(Ne / (60 × 1000)} (9)
As described above, it can also be calculated by searching a table having the contents shown in FIG. 5 from the engine speed Ne.

  The piston behavior flow index calculation unit 58 calculates the piston behavior flow index IND2 [unnamed number] from the average piston speed ΔST by the following equation.

IND2 = ΔST × factor 2 (10)
Here, the coefficients 1 and 2 are values for replacing the kinetic energy U of the intake valve passage fluid and the average piston speed ΔST with indices. The indicators IND1 and IND2 are numbers without units, and are values having a range of 5 or 10 levels, for example. Here, as the value of the index IND1 increases, the strength of the flow generated in the combustion chamber 5 by the air-fuel mixture flowing through the intake valve 15 and flowing into the combustion chamber 5 during the open period of the intake valve 15 increases. The index IND2 means that the greater the value, the greater the strength of the flow generated in the combustion chamber 5 due to the behavior of the piston 6.

  The combustion chamber flow index calculation unit 59 calculates a combustion chamber flow index IND3 by searching a map having the contents shown in FIG. 7 from the intake flow index IND1 and the piston behavior flow index IND2. This index IND3 is also a value with, for example, a range of 5 steps or 10 steps, and the larger the value, the greater the strength of gas flow in the combustion chamber. As shown in FIG. 7, the combustion chamber flow index IND3 increases as the piston behavior flow index IND2 increases when the intake flow index IND1 is constant, and the intake flow index IND1 increases when the piston behavior flow index IND2 is constant. It gets bigger.

  In addition, the above coefficients 1 and 2 include numerical values for adjusting the scales of the vertical and horizontal axes in FIG. Coefficients 1 and 2 are finally set by matching.

  In this way, the intake flow index IND1 indicates the gas flow generated in the combustion chamber 5 by the air-fuel mixture (intake valve passage fluid) that passes through the intake valve 15 and flows into the combustion chamber 5 during the open period of the intake valve 15. The piston behavior flow index IND2 represents the strength of the gas flow generated in the combustion chamber 5 due to the behavior of the piston 6, and the combustion chamber flow index IND3 represents the strength of the gas flow in the combustion chamber 5.

  Since the intake valve passage instantaneous flow velocity Vi and the combustion chamber inflow instantaneous air flow rate Cc are instantaneous values, the kinetic energy U of the intake valve passage fluid is also an instantaneous value. Therefore, if the intake valve passage instantaneous flow rate Vi and the combustion chamber inflow instantaneous air flow rate Cc change during the intake valve opening period, the kinetic energy U of the intake valve passage fluid changes, and the intake flow index IND1 also changes. Accordingly, the kinetic energy U of the intake valve passage fluid used for the calculation of the intake flow index IND1 is the average value of the intake valve passage instantaneous flow rate Vi during the intake valve opening period and the intake chamber opening instantaneous air flow rate Cc during the intake valve opening period. It is conceivable to use the average value of. Alternatively, it is conceivable to use Vi and Cc at a specific crank angle during the intake valve opening period.

  As described above, the present embodiment introduces the combustion chamber flow index IND3 representing the strength of gas flow in the combustion chamber. In this case, it is the intake valve passing fluid that contributes to the gas flow in the combustion chamber 5. Approximate kinetic energy U and piston behavior, of which the flow parameter relating to the kinetic energy U of the fluid passing through the intake valve is introduced as the intake flow index IND1, and the flow parameter relating to the piston behavior is introduced as the piston behavior flow index IND2. The combustion chamber flow index IND3 is obtained based on these two indexes IND1 and IND2.

  The combustion chamber flow index IND3 obtained in this way is a representative value representing the gas flow in the combustion chamber 5, and this gas flow representative value is reflected in the ignition timing control.

  For example, in Japanese Patent Laid-Open No. 200-148236, the basic ignition timing MBTCAL is set as follows. That is, if the crank angle at which the combustion pressure of the air-fuel mixture reaches the maximum pressure Pmax when the air-fuel mixture is ignited with MBT (minimum advance value for obtaining the maximum torque) is the reference crank angle θPMAX [degATDC], the reference crank angle θPMAX Is almost constant regardless of the combustion method, and is generally in the range of 12 to 15 degrees after compression top dead center and at most 10 to 20 degrees after compression top dead center. The combustion mass ratio representing the ratio of the combustion mass to the fuel supplied to the combustion chamber is 0% at the time of ignition, and reaches 100% after complete combustion. It has been confirmed that the combustion mass ratio at the reference crank angle θPMAX is constant and about 60%.

  A section until the combustion mass ratio reaches 2% is defined as an initial combustion period BURN1 [deg], a section from the end of the initial combustion period BURN1 to the reference crank angle θPMAX is defined as a main combustion period BURN2, and these initial combustion periods BURN1 And the main combustion period BURN2 are calculated by the following equation.

BURN1 = (Ne × 6) × BR1 × V0
/ (RPROBA × AF1 × FLAME1) (11)
However, BR1: change margin of combustion mass ratio (2%) from the combustion start time to the end of the initial combustion period,
V0: volume [m ³ ] at the combustion start timing of the combustion chamber,
RPROBA; reaction probability [%],
AF1; reaction area of the flame kernel (fixed value) [m ² ],
FLAME1; burning speed [m / sec] in the initial burning period,
BURN2 = (Ne × 6) × BR2 × VTDC
/ (RPROBA × AF2 × FLAME2) (12)
However, BR2: change amount of combustion mass ratio from start time of main combustion period to end time of main combustion period (58%),
VTDC: combustion chamber volume at compression top dead center [m ³ ],
RPROBA; reaction probability [%],
AF2: Reaction area of flame kernel (fixed value) [m ² ],
FLAME2: burning speed [m / sec] in the main burning period,
The value obtained by adding these BURN1 and BURN2 is the combustion period BURN [deg], and the reference crank angle θPMAX [degATDC] is advanced by the total crank angle section obtained by adding the combustion period BURN and the ignition dead time crank angle IGNDEAD [deg]. The angled crank angle position is set as the basic ignition timing MBTCAL [degBTDC], which is the ignition timing at which MBT is obtained.

  The above burning rates FLAME1 and FLAME2 are given by the following equations.

FLAME1 = SL1 × ST1 (13)
However, SL1: Disturbance strength in the initial combustion period,
ST1: Laminar burning velocity in the initial combustion period,
FLAME2 = SL2 × ST2 (14)
However, SL2: turbulence intensity in the initial combustion period,
ST2: Laminar burning velocity in the initial combustion period,
In this case, the turbulence strengths ST1 and ST2 of the gas flow are given according to the engine rotation speed in Japanese Patent Laid-Open No. 2003-148236, but in the present invention, instead of this, from the combustion chamber flow index IND3, The gas flow turbulence strengths ST1 and ST2 are set.

ST1 = constant 2 × IND3 (15)
ST2 = constant 3 × IND3 (16)
Alternatively, the turbulence strengths ST1 and ST2 of the gas flow are set from the intake flow index IND1 and the piston behavior flow index IND2 by the following equation.

ST1 = constant 4 × IND1 (17)
ST2 = constant 5 × IND1 (18)
ST1 = constant 6 × IND2 (19)
ST2 = constant 7 × IND2 (20)
Here, the operation of the present embodiment will be described.

  In the present embodiment, the intake flow index IND1 and the piston behavior flow index IND2 are calculated, and the combustion chamber flow index IND3 is calculated based on these.

  Here, the intake flow index IND1 indicates the strength of the gas flow generated in the combustion chamber by the air-fuel mixture (intake valve passing fluid) that passes through the intake valve 15 and flows into the combustion chamber 5 during the open period of the intake valve 15. The piston behavior flow index IND2 represents the strength of the gas flow generated in the combustion chamber due to the behavior of the piston, and the combustion chamber flow index IND3 represents the strength of the gas flow in the combustion chamber 5.

  That is, according to the present embodiment (the invention described in claim 1), the gas generated in the combustion chamber by the intake valve passage fluid that flows through the intake valve 15 and flows into the combustion chamber 5 while the intake valve 15 is open. A special sensor is used to calculate the strength of the flow, calculate the strength of the gas flow generated in the combustion chamber by the behavior of the piston, and calculate the strength of the gas flow in the combustion chamber based on the strength of the gas flow. The strength of the gas flow in the combustion chamber can be obtained with a simple configuration without using.

  According to this embodiment (the invention described in claim 2), the strength of the gas flow generated in the combustion chamber by the intake valve passage fluid is calculated based on the kinetic energy of the intake valve passage fluid. Can be obtained with a simple configuration.

  According to this embodiment (the invention described in claim 3), the kinetic energy U of the intake valve passage fluid is calculated based on the intake valve passage flow velocity Vi and the intake valve passage mass flow rate Cc. The kinetic energy U can be obtained with a simple configuration.

  According to the present embodiment (the invention described in claim 4), the intake valve passage flow rate Vi is calculated based on the pressure ratio Pc / Pp before and after the intake valve, so that the intake valve passage flow rate Vi can be obtained with a simple configuration. Can do.

  According to this embodiment (the invention described in claim 5), the intake valve passage mass flow rate Cc is calculated based on the intake valve passage flow velocity Vi, the intake valve opening area Ain, and the density ρ of the intake valve passage fluid. The intake valve passage mass flow rate Cc can be calculated with a simple configuration.

  According to the present embodiment (the invention described in claim 6), the flow strength (IND2) generated in the combustion chamber by the piston behavior is calculated based on the piston speed ΔST, so the flow generated in the combustion chamber by the piston behavior. Can be calculated with a simple configuration.

  According to the present embodiment (the invention described in claim 7), the flow strength (IND1) generated in the combustion chamber by the intake valve passage fluid is determined from the pressure ratio Pc / Pp before and after the intake valve, and the opening area of the intake valve 15. Since the calculation is based on Ain and the density ρ of the intake valve passage fluid, the strength of the flow generated in the combustion chamber by the intake valve passage fluid can be obtained with a simple configuration.

  According to the present embodiment (the invention described in claim 10), since the strength of gas flow is represented by an index, the physical quantity of the strength of gas flow can be easily handled.

  In the embodiment, the case where the combustion chamber flow index IND3 is calculated from the intake flow index IND1 and the piston behavior flow index IND2 has been described. However, as shown in FIGS. 8A and 8B, the intake flow index IND1 or The combustion chamber flow index IND3 may be calculated from the piston behavior flow index IND2 (the invention according to claim 1).

  In the embodiment, the case where the intake valve passage flow rate and the intake valve passage mass flow rate are obtained as instantaneous values has been described. However, the present invention is not limited to this, and the intake valve opening flow rate and the intake valve passage mass flow rate are not limited to this. You may make it obtain | require by the average value in inside.

  In the embodiment, the intake valve passage mass flow rate Cc is calculated based on the intake valve passage flow rate Vi, the opening area Ain of the intake valve 15 and the density ρ of the intake valve passage fluid. However, the intake valve passage mass flow rate Cc is described. Can also be calculated based on at least one of the intake valve passage flow rate Vi, the opening area Ain of the intake valve 15, and the density ρ of the intake valve passage fluid (the invention according to claim 5).

  In the embodiment, the flow strength generated in the combustion chamber 5 due to the piston behavior has been described based on the piston speed ΔST. However, the flow strength generated in the combustion chamber due to the piston behavior is referred to as the engine rotation speed. It may be calculated based on the invention (the invention according to claim 6).

  In the embodiment, the strength of the flow generated in the combustion chamber 5 by the intake valve passage fluid is calculated based on the pressure ratio Pc / Pp before and after the intake valve, the opening area Ain of the intake valve 15 and the density ρ of the intake valve passage fluid. As described above, the strength of the flow generated in the combustion chamber 5 by the intake valve passage fluid is expressed by the pressure ratio Pc / Pp before and after the intake valve, the opening area Ain of the intake valve 15, and the density ρ of the intake valve passage fluid. You may make it calculate based on at least one (invention of Claim 7).

  Although not described in the embodiment, it is based on at least one of the four parameters of the pressure ratio Pc / Pp before and after the intake valve, the opening area Ain of the intake valve 15, the density ρ of the intake valve passage fluid, and the piston speed ΔST. Thus, the four parameters of the pressure ratio Pc / Pp before and after the intake valve, the opening area Ain of the intake valve 15, the density ρ of the fluid passing through the intake valve, and the engine rotational speed Ne are calculated. The strength of the gas flow in the combustion chamber may be calculated based on at least one of the parameters (inventions according to claims 8 and 9).

  The function of the first flow strength calculating means according to claim 1 is performed by the intake flow index calculating section 56 in FIG. 2, and the function of the second flow strength calculating means is performed by the piston behavior flow index calculating section 58 in FIG. The function of the indoor flow strength calculation means is performed by the combustion chamber flow index calculation unit 59 of FIG.

The schematic block diagram which shows one Embodiment of this invention. The control block diagram for demonstrating calculation of a combustion chamber flow parameter | index. The flowchart for demonstrating calculation of the instantaneous pressure of a combustion chamber. The characteristic diagram of an intake valve opening area. The characteristic figure of average piston speed. The characteristic diagram of the intake valve opening area about an engine provided with a variable valve apparatus. The characteristic figure of a combustion chamber flow parameter | index. The characteristic view of the combustion chamber flow index of another embodiment.

Explanation of symbols

5 Combustion chamber 21 Fuel injection valve 31 Engine controller 33, 34 Crank angle sensor 36 Pressure sensor 37 Temperature sensor

Claims (10)

An intake valve at the opening to the combustion chamber of the intake port for opening and closing the combustion chamber;
An engine comprising: a piston that lowers when the intake valve opens the combustion chamber and sucks air from the intake port into the combustion chamber;
First flow strength calculation means for calculating the strength of gas flow generated in the combustion chamber by the intake valve passage fluid passing through the intake valve and flowing into the combustion chamber during the opening period of the intake valve;
Second flow strength calculating means for calculating the strength of gas flow generated in the combustion chamber by the behavior of the piston;
An engine gas flow detection device comprising: combustion chamber flow strength calculation means for calculating the strength of gas flow in the combustion chamber based on at least one of these gas flow strengths.   The engine gas flow detection device according to claim 1, wherein the strength of gas flow generated in the combustion chamber by the intake valve passage fluid is calculated based on the kinetic energy of the intake valve passage fluid.   The engine gas flow detection device according to claim 2, wherein the kinetic energy of the intake valve passage fluid is calculated based on an intake valve passage flow velocity and an intake valve passage mass flow rate.   The engine gas flow detection device according to claim 3, wherein the intake valve passage flow velocity is calculated based on a pressure ratio before and after the intake valve.   The engine according to claim 3, wherein the intake valve passage mass flow rate is calculated based on at least one of the intake valve passage flow velocity, the opening area of the intake valve, and the density of the intake valve passage fluid. Gas flow detection device.   The engine gas flow detection device according to claim 1, wherein the strength of the flow generated in the combustion chamber by the piston behavior is calculated based on a piston speed or an engine rotation speed.   The strength of the flow generated in the combustion chamber by the intake valve passage fluid is calculated based on at least one of the pressure ratio before and after the intake valve, the opening area of the intake valve, and the density of the intake valve passage fluid. The gas flow detection device for an engine according to claim 1. An intake valve at the opening to the combustion chamber of the intake port for opening and closing the combustion chamber;
An engine comprising: a piston that lowers when the intake valve opens the combustion chamber and sucks air from the intake port into the combustion chamber;
The strength of gas flow in the combustion chamber is calculated based on at least one of the four parameters of the pressure ratio before and after the intake valve, the opening area of the intake valve, the density of the fluid passing through the intake valve, and the piston speed. An engine gas flow detection device characterized in that: An intake valve at the opening to the combustion chamber of the intake port for opening and closing the combustion chamber;
An engine comprising: a piston that lowers when the intake valve opens the combustion chamber and sucks air from the intake port into the combustion chamber;
The strength of the gas flow in the combustion chamber is calculated based on at least one of the four parameters of the pressure ratio before and after the intake valve, the opening area of the intake valve, the density of the fluid passing through the intake valve, and the engine speed. An engine gas flow detection device characterized in that:   The engine gas flow detection device according to claim 1, wherein the strength of the gas flow is represented by an index.

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