JP4565435B2 - Control method of flywheel energy storage drive - Google Patents

Description

  The present invention intermittently accumulates the output power that the heat engine operates on its economic fuel consumption characteristic line as it is in the mechanical power directly on the flywheel, and the flywheel energy accumulation that drives the vehicle by the power accumulated in the flywheel. The present invention relates to a drive control method.

Conventionally, there is the vehicle drive mechanism of FIG.
In FIG. 6, the drive shaft 1 a of the gasoline engine 1 (hereinafter simply referred to as the engine 1) is linked to the generator 2, and the electric power generated by the generator 2 is supplied to the electric motor 5 via the controller 3. .
Further, between the controller 3 and the power source 4 is a mechanism for charging power from the controller 3 to the power source 4 or discharging power from the power source 4 to the controller 3.

  The output shaft 5a of the electric motor 5 is linked to the drive wheels 6 and 6 via a differential gear 6a (hereinafter simply referred to as a differential 6a) and drive shafts 6b and 6b.

As shown in FIG. 5, the engine 1 has an economic fuel consumption characteristic line Fec that provides the best fuel consumption rate (hereinafter simply referred to as fuel consumption rate) for each rotational speed Ne of the drive shaft 1 a.
In FIG. 5, the vertical axis represents the output torque Te of the engine 1, and the horizontal axis represents the rotational speed Ne of the engine 1.

θm indicates the torque characteristic at the maximum throttle opening of the engine 1, and θi indicates the torque characteristic at an arbitrary throttle opening.
Each of Pem, Pei, Pel, and Pex shows a characteristic of constant output power of the engine 1, and Pem is a value at the time of maximum output power of the engine 1, and the output power decreases in the order of Pem, Pel, and Pex.

  The fuel economy characteristic line Fec has the best fuel efficiency at the feo part surrounded by the dotted line, and the fuel efficiency ratio decreases as the distance from the feo part increases.In particular, the engine idle idling Nidl through the operating points Pl to Px on the fuel efficiency characteristic line Fec The fuel consumption rate of the characteristic part during the period decreases rapidly toward the state of zero efficiency in Nidl.

There are the following two methods for driving the vehicle in FIG.
In the first method, when the driver instructs the drive shaft T2 to the output shaft 5a, the controller 3 determines that the required power in the output shaft 5a at that time, that is, the product of the drive torque T2 and the rotational angular velocity ω2 (T2 × ω2). Ask for.

At the same time, the controller 3 obtains power corresponding to the required power in the engine 1, for example, power Pei in FIG. 5, and performs control to set the operation of the engine 1 to the operating point Pi on the economic fuel consumption characteristic line Fec.
That is, the controller 3 sets the throttle opening of the engine 1 to θi and sets the generator 2 so that the load torque of the drive shaft 1a is Tei or the rotational speed of the drive shaft 1a is Nei.

As a result, the engine 1 generates the generator 2 with the power Pei, and all of the generated power is supplied to the electric motor 5 through the control of the controller 3.
The electric motor 5 converts the electric power into mechanical power, and the power is transmitted to the drive wheels 6 and 6 through the differential 6a and the drive shafts 6b and 6b.

For the above method, there are the following methods.
In this method, the engine 1 intermittently causes the generator 2 to generate electric power with the power more than the required power for the output shaft 5a, and when the engine 1 is operating, the surplus power more than the required power for the output shaft 5a is once. Then, it is stored in the power source 4 such as a secondary battery via the controller 3.
When the stored electric power reaches a predetermined charge level, the controller 3 stops the fuel supply to the engine 1 and supplies electric power corresponding to the required power to the output shaft 5a from the power source 4 to the electric motor 5. .
Nomoto et al .: Development of NE Train. EVS Forum 2005, Japan Automobile Research Institute.

The former driving method is a method in which all the generated power of the engine 1 is directly output to the output shaft 5a. Therefore, when the required power to the output shaft 5a is equal to or less than Pel in FIG. 5, the engine 1 in that case The operating point is, for example, a Px point between Pl and Nidl on the economic fuel consumption characteristic line Fec, and the fuel consumption of the engine 1 is very poor.
In particular, the power between Pl and Nidl corresponds to the vehicle driving power when driving in an urban area, and the poor fuel consumption deteriorates the fuel consumption from the fuel full tank to the next fuel full tank.

  Next, in the latter method, while the engine 1 is driving the generator 2, the surplus power generated by the generator 2 is temporarily charged into the power source 4 and the fuel supply to the engine 1 is stopped. In the meantime, the electric motor 5 is driven by the electric power from the power source 4.

Therefore, the energy loss when charging the surplus power to the power source 4 and the energy loss when discharging the power of the power source 4 to the electric motor 5 cause deterioration of fuel consumption.
The object of the present invention is to operate the engine 1 between Pl and Pm with excellent fuel efficiency on the economic fuel consumption characteristic line Fec, and to the electric motor 5 all the power generated by the generator 2 without charging / discharging the battery or the like at all times. It is an object of the present invention to provide a flywheel energy storage drive control method that can be supplied to improve fuel efficiency.

The drive shaft (1a) of the heat engine (1) is linked to the generator (2) via the flywheel (6), and all the electric power generated by the generator is output to the output shaft (via the controller (3)). It is a mechanism for supplying to the electric motor (5) for driving 5a).

When the heat engine is operated, the heat engine is operated between a predetermined low output operating point (Pl) and a predetermined high output operating point (Pm) on the economic fuel consumption characteristic line (Fec) of the heat engine.
When the power output from the heat engine at the predetermined high-power operating point (Pm) is Pem, and the accelerator pedal depression amount Acc that instructs the required power to the output shaft is 0 ≦ Acc ≦ 1.0, the flywheel The power generation input power P1 that is generated by the generator using the rotational energy of is controlled to a relationship of P1 = Acc × Pem.

The rotational speed of the heat engine at the accelerator pedal depression amount Acc when the heat engine starts to supply rotational energy to the flywheel is the operating point on the economic fuel consumption characteristic line that outputs power equal to or greater than the power generation input power P1. Pj rotation speed Nej.

When the rotational speed of the flywheel is reduced to a limit rotational speed Nfmin that is equal to the rotational speed Nej corresponding to the accelerator pedal depression amount, the heat engine is predetermined from the operating point Pj on the economic fuel consumption characteristic line. Rotational energy is supplied to the flywheel by operating up to the operating point Pk at which the maximum rotational speed Nemax is reached.

After the rotational speed of the flywheel reaches a predetermined maximum rotational speed Nfmax equal to the predetermined maximum rotational speed Nemax corresponding to the accelerator pedal depression amount, the flywheel rotational speed is the limit rotational speed. When the speed is decreasing until the speed reaches Nfmin, the fuel supply to the heat engine is stopped.

According to claim 1, when the engine 1 is in operation, the power more than the required power for the output shaft 5a is stored in the flywheel 6, and the generator 2 only supplies the required power for the output shaft 5a to the flywheel. 6, all of the required power is transmitted to the output shaft 5 a via the electric motor 5.
Accordingly, there is no energy loss due to charging from the generator 2 to the power source 4 and discharging from the power source 4 to the electric motor 5 except during special acceleration, and fuel efficiency can be improved accordingly.

Regarding the second aspect, the predetermined maximum rotational speed Nemax of the engine 1 during the control of the first aspect and during the driving of the engine 1 has a characteristic of decreasing according to a decrease in the accelerator pedal depression amount Acc. Therefore, when the accelerator pedal depression amount is small, the predetermined maximum rotational speed of the engine 1 is also reduced, which is consistent with the conventional driving feeling and can be operated with a natural feeling.

As for claim 3, by rapidly depressing the accelerator pedal in the control of claim 1, the current rotational speed Nf of the flywheel 6 becomes lower than the limit rotational speed Nfmin of the flywheel corresponding to the new accelerator pedal depression amount. If it has, the flywheel 6 is driven by the heat engine 1.
At that time, until the rotational speed Nf of the flywheel 6 becomes equal to or higher than the limit rotational speed Nfmin corresponding to the new accelerator pedal depression amount, the power generation input power P1 in the generator 3 is rotated by the drive of the engine 1. The electric power corresponding to the reduced power generation input power is supplied from the power source 4 to the motor 5 while the speed is decreased to a level at which the speed increases.
As a result, the electric motor 5 can be driven as required for the output shaft 5a, and the engine 1 can supply rotational energy to the flywheel 6 without stalling the flywheel 6.

The drive shaft (1a) of the heat engine (1) is linked to the generator (2) via the flywheel (6), and all the electric power generated by the generator is output to the output shaft (via the controller (3)). When the heat engine is operated by supplying it to the electric motor (5) that drives 5a), the predetermined high output operation is performed from the predetermined low output operation point (Pl) on the economic fuel consumption characteristic line (Fec) of the heat engine. Operated between points (Pm),
When the power output from the heat engine at the predetermined high-power operating point (Pm) is Pem, and the accelerator pedal depression amount Acc that instructs the required power to the output shaft is 0 ≦ Acc ≦ 1.0, the flywheel The power generation input power P1 generated by the generator using the rotational energy of the engine is controlled to a relationship of P1 = Acc × Pem, and the accelerator pedal depression amount Acc when the heat engine starts to supply rotational energy to the flywheel is controlled. The rotational speed of the heat engine at is the rotational speed Nej of the operating point Pj on the economic fuel consumption characteristic line that outputs power equal to or greater than the power generation input power P1, and the rotational speed of the flywheel is the accelerator pedal depression amount. The heat engine is reduced in the operating speed on the economic fuel consumption characteristic line by decreasing to the limit rotational speed Nfmin having a value equal to the rotational speed Nej corresponding to It operates from the point Pj to the operating point Pk at which the predetermined maximum rotational speed Nemax is reached, to supply rotational energy to the flywheel, and the rotational speed of the flywheel corresponds to the predetermined amount of depression of the accelerator pedal. When the predetermined maximum rotational speed Nfmax equal to the maximum rotational speed Nemax is reached and the flywheel rotational speed is decreasing until reaching the limit rotational speed Nfmin, the heat engine Stop the fuel supply to

FIG. 1 is a system diagram of a flywheel energy storage drive apparatus for performing a flywheel energy storage drive control method according to the present invention.
In FIG. 1, the engine 1 is linked to the generator 2 via a drive shaft 1 a, a clutch 1 b and a flywheel 6.

The wiring 3a output from the generator 2 is connected to the electric motor 5 through the controller 3 and the wiring 3b, and the electric motor 5 is linked to the drive wheel through the output shaft 5a.
A power source 4 such as a secondary battery or a capacitor and the controller 3 are connected by a wiring 4a.

The operation of the vehicle equipped with the flywheel energy storage drive device of FIG. 1 is as follows.
When starting the vehicle of FIG. 1, when the driver turns on the key and switches it on, the controller 3 engages the clutch 1b and connects the power from the power source 4 to the wiring 4a, the controller 3 and the wiring 3a. The motor is caused to act on the generator 2 via
Due to the motor action, the generator 2 starts the engine 1 via the input shaft 6a, the flywheel 6, the clutch 1b, and the drive shaft 1a, and the vehicle is ready to start.

When the driver depresses the accelerator pedal from that position, the control device 3 engages the clutch 1b and operates the engine 1.
As a result, the power from the engine 1 accelerates the flywheel 6 to a predetermined rotational speed via the drive shaft 1a and the clutch 1b, and drives the generator 2 via the input shaft 6a.
At that time, the electric power generated by the generator 2 corresponds to the power corresponding to the amount of depression of the accelerator pedal.

In this case, when the charging power in the power source 4 reaches a predetermined value, all the power generated in the generator 2 is supplied to the electric motor 5 via the controller 3 and the wiring 3b, and the electric power is supplied by the electric motor 5. The power is converted into mechanical power, and the mechanical power is transmitted from the output shaft 5a to the drive wheels.

In the power transmission, when the rotational speed of the engine 1 reaches a predetermined maximum rotational speed, the controller 3 stops the fuel supply to the engine 1 and opens the clutch 1b.
After stopping the fuel supply to the engine 1, the controller 3 causes the generator 2 to generate electric power using the rotational energy accumulated in the flywheel 6, and the generated electric power is depressed by the accelerator pedal as in the operation of the engine 1. It corresponds to the power according to the amount.

While the engine 1 intermittently supplies rotational energy to the flywheel 6 as described above, the operation for extracting necessary power from the flywheel 6 to the output shaft 5a is as follows.
The product T1 × ω1 of the rotational angular velocity ω1 of the input shaft 6a and the torque T1 of the input shaft 6a is the input mechanical power P1 to the generator 2, and the power output from the motor 5 to the output shaft 5a is the rotational angular velocity of the output shaft 5a. The product of ω2 and the torque T2 of the output shaft 5a is T2 × ω2 = P2.
Here, the mechanical power P1 of the input shaft 6a is converted into electric power in the generator 2, all of the electric power is supplied to the electric motor 5, and the power transmission efficiency until the electric power is converted into the mechanical power P2 of the output shaft 5a is η. Then
(T1 × ω1) × η = (T2 × ω2) (1)
Here, assuming that the rotational speed of the input shaft 6a is N1 and the rotational speed of the output shaft 5a is N2, ω2 / ω1 = N2 / N1.
(T1 × N1) × η = (T2 × N2) (2)
It becomes.

FIG. 2 shows that the engine 1 outputs the maximum output power Pem by the operation at a predetermined high output operating point Pm, and that power does not give any rotational energy to the flywheel 6 via the drive shaft 1a and the clutch 1b. The relationship between the torque T2m and the rotational speed N2 in the output shaft 5a when the power is transmitted to the input shaft 6a and the power is further transmitted to the output shaft 5a according to the relationship of the equation (2) is shown.
However, the constant T2m = T2max characteristic in the range of 0 ≦ N2 ≦ N2o in FIG. 2 is a torque limited by the maximum possible output torque of the electric motor 5.

  When the driver depresses the accelerator pedal to drive the vehicle, when the accelerator pedal depression amount is the depression amount Acc at a predetermined magnitude, the depression amount is Acc = 1.0, and the condition where the accelerator pedal depression amount is less than 0 is 0 ≦ Acc <1.0.

When the required torque T2 is commanded to the output shaft 5a by such an accelerator pedal depression amount Acc, the control device 3
T2 = Acc x T2mi (3)
From the relational expression, the torque T2 to be output to the output shaft 5a at that time is calculated.
Here, T2mi in the expression (3) is a case where the engine 1 outputs the maximum power Pem and the power is transmitted to the output shaft 5a without supplying any energy to the flywheel 6 as shown in FIG. The output shaft torque T2mi in a state where the rotational speed of the output shaft 5a at that time is N2i.

Also, in equation (3), if both sides are multiplied by the rotational angular velocity ω2 at that time of the output shaft 5a,
T2 x ω2 = Acc x (T2mi x ω2) (4)
It becomes.

(T2mi × ω2) on the right side of the equation (4) is the output shaft when the engine 1 transmits power to the output shaft 5a without supplying any energy to the flywheel 6 as described above. This corresponds to the power P2m generated in 5a (hereinafter simply referred to as output shaft power P2m at the time of engine maximum power).
That is, requesting the torque T2 to the output shaft 5a according to the accelerator pedal depression amount Acc outputs to the output shaft 5a power corresponding to Acc (0 ≦ Acc ≦ 1.0) times the output shaft power P2m at the maximum engine power. I will let you.

  As described above, in order to output the torque T2 to the output shaft 5a according to the accelerator pedal depression amount Acc, that is, to output the power (T2 × ω2) to the output shaft 5a, the generator 2 is operated as described above. The power of the power (T1 × ω1) satisfying the relationship of the expression (1) is taken out from the wheel 6.

Here, if equation (1) is transformed,
T1 = {T2 × (ω2 / ω1)} / η
Since ω2 / ω1 = N2 / N1 as described above,
T1 = {T2 × (N2 / N1)} / η (5)
It becomes.
In equation (5), N1 is the rotational speed of the flywheel 6, and N2 is the rotational speed of the output shaft 5a, so that N1 and N2 can be detected.
The power transmission efficiency η may be obtained experimentally and stored in the controller 3.

That is, when the driver depresses the accelerator pedal and gives an instruction to output torque T2 to the output shaft 5a, the controller 3 calculates the value of T2 according to the relationship of the expression (3), and the calculated value of T2 is ( 5) Substitute into the equation to determine the power generation torque T1.
As described above, the electric power from the generator 2 generated by setting the power generation torque T1 is supplied to the electric motor 5 through the wiring 3a, the controller 3, and the wiring 3b.

In the above operation, the flywheel 6 must be in a state where energy can be supplied to the generator 2 by satisfying the relationship of the expression (1) “always”.
The "always" means that the rotational energy must be stored in the flywheel 6 so that power can be continuously supplied from the flywheel 6 to the generator 2 not only temporarily. That is.
That is, the flywheel 6 must always be replenished with energy from the engine 1 to satisfy the relationship of the expression (4).

Hereinafter, an operation in which the engine 1 supplies rotational energy to the flywheel 6 will be described.
When the engine 1 is operated to supply rotational energy to the flywheel 6, the clutch 1b is engaged, and when the output torque of the engine 1 at that time is Te and the inertia moment of the flywheel 6 is If,
Te = {I × (dω1 / dt)} + T1
The torque balance equation is obtained.
Dω1 / dt is the rotational angular acceleration of the flywheel 6.
Rewriting the above formula,
dω1 / dt = (Te-T1) / I (6)
It becomes.

In the equation (6), when Te <T1, the rotational angular acceleration dω1 / dt of the flywheel 6 becomes negative, and even if the engine 1 tries to drive the flywheel 6, the rotational speed of the flywheel 6 is stalled. Will end up.
Here, in FIG. 1, when the clutch 1b is engaged, the rotational angular velocity ωe of the engine 1 and the rotational angular velocity ω1 of the input shaft 6a are the same, that is, ωe = ω1, and therefore (Te <T1) in the equation (6) Is the same as the comparison of power magnitude (Te × ω1) <(T1 × ω1).

That is, in order not to stall the flywheel 6 when the engine 1 is driven, in order to make dω1 / dt in the expression (6) positive, it is necessary to set (Te − T1) on the right side of the expression (6) to a positive value. The output power Te × ωe (= Te × ω1) of the engine 1 is always larger than the power T1 × ω1 in the input shaft 6a.
Te × ωe> T1 × ω1
It means that you have to be in a relationship.
In the above equation, Te × ωe is an arbitrary output power Pej output from the engine 1, and therefore the output power Pej of the engine 1 that drives the engine 1 without stalling the flywheel 6 is
Pej> T1 × ω1 (7)
Need to be in a relationship.

Here, from the equations (1) and (3),
T1 × ω1 × η = Acc × (T2mi × ω2)
Or
T1 × ω1 = Acc × (T2mi × ω2) / η
(T2mi × ω2) / η in the above equation is the maximum output power Pem of the engine 1 as can be understood from the description of FIG.
Therefore, the above formula is
T1 × ω1 = Acc × Pem (8)
Are in a relationship.
Therefore, from the equations (7) and (8), the magnitude of the power Pej output from the engine 1 without stalling the flywheel 6 is
Pej> Acc x Pem (9)
Must be in a relationship.

The operation of the engine 1 according to the present invention operates between the predetermined low output operating point P1 and the predetermined high output operating point Pm on the economic fuel consumption characteristic line Fec in FIG. However, it is not used between the operating points Pl and Nidl, which greatly deteriorates the fuel consumption.
The point Pl in FIG. 5 is a point at which the fuel consumption rate rapidly deteriorates from the operating point Pm on the economic fuel efficiency characteristic line Fec to the idling operating point Nidl via the operating point Pl. That is, the fuel consumption rate is good from the operating point Pm to the operating point Pl on the economic fuel consumption characteristic line Fec, and the fuel consumption rate rapidly deteriorates from the operating point Pl to the idling operating point Nidl via the operating point Px. .
Therefore, in the present embodiment, the relationship between the accelerator pedal depression amount Acc that satisfies the expression (9) and the output of the engine 1 when the engine 1 is operating is set as follows.

The expression (9) performs control to increase the output power Pej of the engine 1 to Acc times “more than” the maximum output power Pem of the engine 1 when the engine 1 is operating.
For each accelerator pedal depression amount Acc, a power characteristic Acc × Pem constant characteristic curve Pei obtained according to the relationship on the right side of equation (9) is drawn on FIG. 5, and the drawn characteristic Pei curve and economic fuel consumption characteristic line Fec Is obtained, and the rotational speed Nei of the engine 1 at the obtained operating point Pi is obtained.

The output power Pei of the engine 1 at the operating point Pi on the economic fuel consumption characteristic line Fec at which the rotation speed thus determined is Nei is the power that satisfies the right side of the equation (9).
That is, in the process in which the rotational speed Nf of the flywheel 6 decreases due to the engine 1 being in an inoperative state and the generator 2 taking the energy from the flywheel 6 and running the vehicle, the flywheel When the rotational speed Nf of the engine 6 decreases to “just before” when the rotational speed Nf is equal to the above-obtained rotational speed of Nei, the engine 1 is operated on the fuel economy characteristic line Fec, and the rotational speed is If the operation starts from the "immediately preceding" rotational speed, rotational energy can be supplemented from the engine 1 to the flywheel 6 without stalling the flywheel 6.

Here, the "immediately before" rotational speed of "when Nei falls to" immediately before "" is the rotational speed Ne = Nei + dNe immediately before the rotational speed Ne of the engine 1 becomes Nei in FIG. .
In FIG. 5, when the rotational speed Ne of the engine 1 is Ne = Nei + dNe and the operation is performed at the operating point Pj on the economic fuel consumption characteristic line Fec, the output power of the engine 1 at the operating point Pj is As can be understood from FIG. 5, the value of Pei + dPe is slightly larger than the power of Pei.

That is, in the process in which the rotational speed Nf of the flywheel 6 decreases due to the engine 1 being in an inoperative state and the generator 2 taking the energy from the flywheel 6 and running the vehicle, the flywheel When the rotational speed Nf of the engine 6 reaches the value Nei + dNe, if the engine 1 starts to operate at the operating point Pj on the fuel economy characteristic line Fec, the engine 1 should be driven without stalling the flywheel 6. I can do it.

In the process in which the rotational speed Nf of the flywheel 6 decreases as the engine 1 is deactivated and the generator 2 extracts energy from the flywheel 6 to drive the vehicle as described above, the engine 1 FIG. 3 shows a criterion for restarting and replenishing rotational energy to the flywheel 6 based on the above theory.

In FIG. 3, the vertical axis represents the rotational speed Nf of the flywheel 6, and the horizontal axis represents the accelerator pedal depression amount Acc.
The limit rotational speed characteristic Nfmin of the flywheel 6 in FIG. 3 is obtained as follows.
In equation (9), for each Acc, Acc × Pem = Pei on the right side is obtained, and an operating point Pi for outputting the power Pei is obtained on the economic fuel consumption characteristic line Fec of FIG. The rotational speed Nei (vertical axis) obtained by adding dNe to the obtained rotational speed Nei in correspondence with each Acc (horizontal axis) is plotted.
That is, the obtained rotation speed Nej is the value of the vertical axis (Nf) of the characteristic Nfmin in FIG.

In the relationship of the above equation (9), when Acc = 1.0, the maximum output power Pem of the engine 1 is output to the input shaft 6a from the relationship of the equation (8).
In addition, the engine 1 is controlled so as not to rotate above the rotational speed Nem of the operating point Pm that outputs the maximum output power Pem.
Therefore, when Acc = 1.0 in the relationship of the expression (9), the control is performed such that the rotational speed of the engine 1 is not further increased even when the engine 1 is being driven. In this case, the flywheel 6 is further increased in speed. The power Pem of the engine 1 is continuously applied to the input shaft 6a.
That is, in the case of Acc = 1.0 in equation (9), the inequality sign in equation (9) is replaced with an equal sign to Pej = Pem, and the action continues to output all the maximum output power Pem of the engine 1 to the input shaft 6a. It will be.

Therefore, the point m in the limit rotational speed characteristic Nfmin in FIG. 3 indicates the rotational speed Nf of the flywheel 6 (equal to the rotational speed of the engine 1 at this time) when the accelerator pedal depression amount Acc is Acc = 1.0. Is controlled so as to be the rotational speed Nem of the maximum power output of the engine 1.

Further, in the limit rotational speed characteristic Nfmin in FIG. 3, the point l is a point set as follows.
As described above, in the present invention, the operation in which the engine 1 replenishes the rotational energy to the flywheel 6 has a predetermined low output operating point Pl on the economic fuel consumption characteristic line Fec in order to keep the fuel consumption of the engine 1 at a predetermined level. Control is performed between the high power operating points Pm.
Further, as described above, the operation of the engine 1 must satisfy the condition of the expression (9) that does not stall the rotational speed Nf of the flywheel 6.
Therefore, a relationship satisfying the condition of the expression (9) in a state where the engine 1 operates at the predetermined low output operating point Pl is necessary for control.

Therefore, if the value of Pej in equation (9) is the output power Pel as described above, equation (9) is
Pej = Pel> Acc × Pem
And organize this,
Acc <Pel / Pem (10)
Get.
That is, if the value of the accelerator pedal depression amount Acc in the state where the operation point of the engine 1 is the predetermined low output operation point Pl is the accelerator pedal depression amount Acc within the range satisfying the relationship of the expression (10), The flywheel 6 will not be stalled during the operation of 1.
Therefore, the value of Acc in equation (10) may be zero.

Also, the accelerator pedal depression amount obtained by using the inequality sign in equation (10) as the equal sign
Acci = Pel / Pem
Even if the accelerator pedal depression amount Acco = Acci-dAcc obtained by subtracting a small amount of dAcc (a value of about dAcc = 0.01) from that Acci is substituted into the equation (10), the equation (10) Holds.
That is, the accelerator pedal depression amount Acc in the range where the accelerator pedal depression amount Acc is 0 <Acc ≦ Acco all satisfies the expression (10).

The value of Acco thus obtained is the value of Acc = Acco on the horizontal axis corresponding to the point l in FIG.
Also, the value of Nf = Nel on the vertical axis corresponding to the point l in FIG. 3 indicates that the power value Pel in the above equation (10) is the operating point Pl on the economic fuel consumption characteristic line Fec (FIG. 5) and its state This corresponds to the rotation speed Ne of the engine 1 at Ne = Nel.
That is, when the accelerator pedal depression amount Acc is in the range of 0 <Acc ≦ Acco, the generator 2 takes out the power (T1 × ω1) of the formula (8) from the flywheel 6 alone, thereby When the rotational speed of the wheel 6 decreases and the flywheel rotational speed Nf reaches Nf = Nel (relationship in FIG. 3), the controller 3 starts the engine 1 from the predetermined low-power operating point Pl and saves fuel economy. The operation is continued as described above until Nf = Nfmax on the characteristic line Fec.

Thus, in the process in which the rotational speed Nf of the flywheel 6 decreases by the engine 1 being in an inoperative state and the generator 2 taking the energy from only the flywheel 6 and running the vehicle, When the engine 1 is restarted and the rotational energy is supplied to the flywheel 6, the following control using the limit rotational speed characteristic Nfmin in FIG. 3 is performed.

In FIG. 3, the rotational speed Nf = Nfmin of the flywheel 6 corresponding to the accelerator pedal depression amount Acc is obtained, and the decreasing rotational speed Nf of the flywheel 6 reaches the rotational speed Nf = Nfmin obtained from FIG. When the engine 1 is made to coincide with the rotational speed of Nfmin and the engine 1 is started on the fuel economy characteristic line Fec, the flywheel 6 does not stall and can be accelerated while satisfying the relationship of the expression (9). .

The operation of the engine 1 after the engine 1 is restarted is operated up to the Pm point (FIG. 5) of the maximum power output point on the fuel economy characteristic line Fec, and the fuel supply to the engine 1 is stopped at the Pm point. May be.
However, even when the driver is driving the vehicle with the accelerator pedal depressed, the operating rotational speed of the engine 1 is in a state of outputting the maximum power, unlike the conventional driving feeling of the vehicle. Will occur.

Here, as described above, during the operation of the engine 1, the rotational speed Ne of the engine 1 is Ne = Nf which is the same as the rotational speed Nf of the flywheel 6.
Therefore, the maximum rotational speed Nemax of the engine 1 reached by the operation of the engine 1 becomes lower as the accelerator pedal depression amount Acc decreases, as the maximum rotational speed characteristic Nfmax (= Nemax) of the flywheel 6 in FIG. Is desirable.

As described above, when the engine 1 drives the flywheel 6 and the input shaft 6a, the controller 3 operates at a rotational speed between the characteristic Nfmin (= Nemin) and the characteristic Nfmax (= Nemax) in FIG. The engine 1 is operated on the economic fuel consumption characteristic line Fec, and the control for operating the engine 1 on the economic fuel consumption characteristic line Fec is as follows.
As can be understood from the above description, the fact that the engine 1 is operated on the fuel economy characteristic line Fec according to the characteristic Nfmin that is the limit rotational speed and the characteristic Nfmax that is the maximum rotational speed set in FIG. (Te-T1) on the right side of is set to a positive value, which means that dω1 / dt (= dωe / dt) on the left side of equation (6) becomes positive and the flywheel 6 rotates. At the same time, it means that the rotational speed Ne of the engine 1 constantly increases.
However, when the accelerator pedal depression amount Acc is Acc = 1.0, the engine 1 continues to operate with the rotational speed Ne of Ne = Nem constant as described above.

In order to perform control so that the engine 1 continues to increase on the fuel economy characteristic line Fec, the control device 3 increases the amount of fuel supplied to the engine 1 over time.
The relationship of increasing the rotational speed Ne of the engine 1 by increasing the fuel supply amount is that the increase rate of the fuel supply amount at each time point is the fuel supply amount θi (FIG. 5) at that time point and the engine 1 at that time point. The rotation speed Nei is increased at a speed that matches the operating point Pi on the economic fuel consumption characteristic line Fec.

FIG. 4 shows changes in the rotational speed Nf of the flywheel 6 when the accelerator pedal depression amount Acc is Acc = 0.4 and Acc = 0.8 in the vehicle traveling by the above control.
In FIG. 4, the vertical axis represents the rotational speed Nf of the flywheel 6, and the horizontal axis represents the elapsed time t.
When the accelerator pedal depression amount Acc in FIG. 4 is both Acc = 0.4 and Acc = 0.8, while the flywheel rotational speed Nf is increasing, the engine 1 accelerates the flywheel 6 and the generator 2 flies. The state where the energy of the relationship of the formula (8) corresponding to the accelerator pedal depression amount Acc is extracted from the wheel 6 is shown.
Further, in FIG. 4, while the flywheel rotational speed Nf is decreasing, the fuel supply to the engine 1 is stopped, and the generator 2 corresponds to the accelerator pedal depression amount Acc only from the flywheel 6 (8) The state of taking out the energy of the relationship is shown.

In FIG. 4, when the accelerator pedal depression amount Acc = 0.4, the flywheel rotational speed Nf repeatedly increases and decreases between Nfa and Nfb.
When the accelerator pedal depression amount is Acc = 0.4, the rotation between point a and point b is based on the characteristics of the limit rotational speed Nfmin and the maximum rotational speed Nfmax of the flywheel 6 set in FIG. This is because the control is performed so as to repeat the ascending and rotating descending.

In FIG. 4, the flywheel rotational speed Nf in the case where the accelerator pedal depression amount Acc = 0.8 is repeatedly increased and decreased between Nfc and Nfd.
Also in this case, when the accelerator pedal depression amount Acc = 0.8, the points c and d are calculated based on the characteristics of the limit rotational speed Nfmin and the maximum rotational speed Nfmax of the flywheel 6 set in FIG. This is because the control is performed so that the rotation rise and the rotation fall repeatedly.

The above explanation is for the case where the accelerator pedal depression amount Acc is constant, but the control when the accelerator pedal depression amount Acc is rapidly depressed is as follows.
For example, it is assumed that the accelerator pedal depression amount Acc is Acc = 0.4, the rotational speed Nf of the flywheel 6 decreases, and the current operating point is point e (FIG. 4).
When the accelerator pedal depression amount Acc is depressed to Acc = 0.8 at the next moment, the rotation speed Nf of the flywheel 6 at the moment of depression is the limit rotation speed Nfmin corresponding to Acc = 0.8 in FIG. The range of the point d from the point c in the characteristics of the maximum rotational speed Nfmax is not satisfied.

  That is, when the accelerator pedal depression amount Acc becomes Acc = 0.8, the rotational speed Nf of the flywheel 6 in FIG. 4 must be Nfc <Nf <Nfd. However, at the moment when Acc = 0.8, the rotational speed Nf of the flywheel 6 is still Nf <Nfc.

Therefore, the control device 3 supplies the fuel to the engine 1 in order to increase the rotational speed Nf of the flywheel 6 that has become too low, and performs the above-described action. Even if the engine 1 is driven, the rotation of the flywheel 6 is stalled.
Until now, in the state where the accelerator pedal depression amount was Acc = 0.4, the output power Pei of the engine 1 substituted Acc = 0.4 into the equation (9).
Pej> 0.4 × Pem
The power of Pej was good.
However, at the “instant” when the accelerator pedal depression amount increased to Acc = 0.8 until the next current time, the output power Pej of the engine 1 newly substituted Acc = 0.8 into the equation (9).
Pej> 0.8 × Pem
This is because it must be a great power of Pej.

In order to solve this problem, the value of equation (9) left side Acc × Pem required for the generator 2 is temporarily reduced, and the power correction corresponding to the reduced value is performed on the electric motor 5 side as follows.
Here, the left side Acc × Pem of the above equation (9) is as shown in the equation (8):
Acc × Pem = T1 × ω1
Therefore, to temporarily reduce the value of the left side Acc × Pem of the equation (9), it is only necessary to reduce T1 on the left side of the equation.

The operation will be described below.
In FIG. 4, when the accelerator pedal depression amount is Acc = 0.4 and the operating point reaches the point e, when the accelerator pedal depression amount is newly increased to Acc = 0.8, the controller 3 returns to the engine 1. While satisfying the operating conditions on the economic fuel consumption characteristic line Fec, the generator torque T1 of the generator 2 is changed until the rotational angular acceleration dω1 / dt (proportional to dNf / dt) of the input shaft 6a becomes a positive value according to the equation (6). Decrease to the value of T1i.

As a result of reducing T1 to T1i and the value of dω1 / dt being positive, that is, the value of dNf / dt becoming positive, the rotational speed Nf of the flywheel 6 increases from the point e (FIG. 4), and f Control continues until the point is reached.
In the control from the point e to the point f, the electric power generated by the generator 2 is reduced by the amount that the T1 is reduced to the value T1i.

That is, the input power of the generator 2 must be originally T1 × ω1 as shown in the equation (1).
However, in the state where the input torque of the input shaft 6a is reduced from T1 to T1i as described above when the accelerator pedal depression amount increases rapidly, the original input power T1 × ω1
(T1-T1i) × ω1 = dP1
The input power is reduced.

This essentially means that the power of dP1 must be transmitted to the electric motor 5 via the control device 3.
This power transmission relationship is expressed by an equation:
dP1 × η = dP2 (11)
It becomes.
However, η is the power transmission efficiency until the input power dP1 to the generator 2 becomes the output power dP2 of the electric motor 5.

That is, in the control from point e to point f in FIG. 4, during the control by reducing T1 to the value of T1i, the output shaft 5a lacks the power dP2 of the expression (11).
For this reason, in the control from the e point to the f point in FIG. 4, the control device 3 replenishes the electric motor 5 via the control device 3 with power corresponding to the output of dP2.
As a result, even in the control from the point e to the point f, it is possible to output the required power to the output shaft 5a corresponding to the accelerator pedal depression amount Acc.

  When the flywheel rotational speed Nf reaches the point f in FIG. 4 by the above control, the rotational speed Nf of the flywheel 6 enters the region of the rotational speed Nfc or more corresponding to the current accelerator pedal depression amount Acc = 0.8, and normal control is performed. After that point f, rotational energy can be supplied from the engine 1 to the flywheel 6, and the flywheel rotational speed Nf increases as shown in FIG.

That is, the fact that the flywheel rotational speed Nf has reached the point f in FIG. 4 indicates that the flywheel rotational speed Nf is the rotation at the point c of the limit rotational speed Nfmin corresponding to the new accelerator pedal depression amount Acc = 0.8 in FIG. The speed Nfc has been reached.
Further, in FIG. 3, when the flywheel rotational speed Nf becomes equal to or higher than the limit rotational speed Nfmin corresponding to the accelerator pedal depression amount Acc, the operation of the engine 1 has again entered the region satisfying the condition of the expression (9). Means.

In the above embodiments, the engine 1 has been described by taking a gasoline engine as an example. However, the engine 1 can be applied to a heat engine such as a diesel engine or a gas turbine.
This is because the heat engine has an economic fuel consumption characteristic line that always improves the fuel consumption in its wide operating rotational speed range. Therefore, when the heat engine supplies rotational energy to the flywheel 6 as described above, Control may be performed so that the operation is intermittent within a preferable range on the economic fuel consumption characteristic line.

Although the clutch 1 is provided in the embodiment of FIG. 1, the drive shaft 1 a of the engine 1 may remain directly connected to the flywheel 6.
However, when the clutch 1b is provided, the engine 1 is not driven from the flywheel 6 side by opening the clutch 1b when the engine 1 is not operated, and the engine 1 is driven in the non-operated state. There is an advantage that there is no torque loss.
However, even when the engine 1 is interlocked with the flywheel 6 while the engine 1 is not operating, the above-described control and driving of the apparatus of FIG. 1 are sufficiently possible.

  The present invention can be applied not only to the above-described automobile but also to a construction machine, a railway vehicle, a ship, and the like as a power transmission device that is used by changing the load power of the output shaft 5a.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a system diagram showing an example of a flywheel energy storage drive device for carrying out the flywheel energy storage drive control method of the present invention. The maximum output torque characteristic T2m with respect to the rotational speed N2 of the output shaft 5a in FIG. 1 is shown. The limit rotational speed Nfmin characteristic of the flywheel 6 when the engine 1 starts to replenish rotational energy to the flywheel 6 and the maximum rotational speed Nfmax characteristic of the flywheel 6 when the rotational energy is supplemented with respect to the accelerator pedal depression amount Acc It is shown. The time change of the rotational speed Nf of the flywheel 6 at the time of using the control method of the flywheel energy storage drive of this invention is shown. FIG. 2 shows the operating characteristics of the engine 1 in FIG. The pure electric drive device which used the engine in the past is shown with the system diagram.

Explanation of symbols

1 engine, 2 generator, 3 controller, 4 power supply, 5 motor, 5a output shaft, 6 flywheel, 6a input shaft, Fec economy fuel consumption characteristic line.

Claims (3)

The drive shaft (1a) of the heat engine (1) is linked to the generator (2) via the flywheel (6), and all the electric power generated by the generator is output to the output shaft (via the controller (3)). 5a) to the electric motor (5) for driving,
When the heat engine is operated, the heat engine is operated between a predetermined low output operating point (Pl) and a predetermined high output operating point (Pm) on an economic fuel consumption characteristic line (Fec) of the heat engine,
When the power output from the heat engine at the predetermined high-power operating point (Pm) is Pem, and the accelerator pedal depression amount Acc that instructs the required power to the output shaft is 0 ≦ Acc ≦ 1.0, the flywheel The power generation input power P1 to be generated by the generator by the rotational energy possessed by is controlled by the relationship P1 = Acc × Pem
The rotational speed of the heat engine at the accelerator pedal depression amount Acc when the heat engine starts to supply rotational energy to the flywheel is an operating point on the economic fuel consumption characteristic line that outputs power of the power generation input power P1 or more. Pj rotation speed Nej,
When the rotational speed of the flywheel is reduced to a limit rotational speed Nfmin that is equal to the rotational speed Nej corresponding to the accelerator pedal depression amount, the heat engine is predetermined from the operating point Pj on the economic fuel consumption characteristic line. Operating up to the operating point Pk at which the maximum rotational speed Nemax becomes, supplying rotational energy to the flywheel,
After the rotational speed of the flywheel reaches a predetermined maximum rotational speed Nfmax equal to the predetermined maximum rotational speed Nemax corresponding to the accelerator pedal depression amount, the flywheel rotational speed is the limit rotational speed. A flywheel energy storage drive control method for stopping the fuel supply to the heat engine when the speed is decreasing until the speed reaches Nfmin. The control method according to claim 1,
The predetermined maximum rotational speed Nemax is a flywheel energy storage drive control method in which the predetermined maximum rotational speed Nemax decreases as the accelerator pedal depression amount Acc decreases. The control method according to claim 1,
When the accelerator pedal depression amount increases and the rotational speed of the flywheel (6) falls below the limit rotational speed Nfmin corresponding to the new accelerator pedal depression amount, the heat engine (1) causes the flywheel ( 6) until the rotational speed of the flywheel becomes equal to or higher than the limit rotational speed Nfmin corresponding to the new accelerator pedal depression amount, the power generation input power P1 in the generator (3) is supplied to the flywheel by the engine. The driving speed of the flywheel is reduced to a level at which the rotational speed of the flywheel increases, and the power transmission efficiency between the generator and the electric motor (5) is reduced to the reduced power generation input power dP1 during the reduction. Flywheel energy storage drive that replenishes the electric motor (5) with power corresponding to dP1 × η = dP2 multiplied by η from the power source (4) Control method of.

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