JPS6053169B2 - Automotive gas turbine control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a two-shaft gas turbine engine for an automobile.

Generally, in a two-shaft gas turbine engine for an automobile, as shown in Fig. 1, the required output is achieved by mainly changing the flow rate Wf of the supplied fuel and the angle α of the power turbine inlet variable guide vane (hereinafter abbreviated as VN). The engine 1 is controlled so that the following results are obtained.

(SAWYER' SGASTURBINEENGIN
EERINGHANDBOOKU, S, A Gas Turbine Publishing 197 details) The rotation speed N of the gas generator shaft is controlled according to the fuel flow rate Wf, while the VN angle α prevents the compressor from surging and operates the engine at an efficient point. It is customary to control it so that it can be done.

Specifically, a subtractor 7 calculates the deviation between the gas generator rotational speed instruction signal Nggset from the accelerator 5 and the actual gas generator rotational speed Nggset, and further this deviation ΔNmg is calculated by a calculation circuit 9 (usually (proportional integral) to set the fuel flow rate command value CVset, and by driving the actuator 11 according to this command value, the flow rate Wf is increased or decreased so that the gas generator rotation speed Nmg becomes the command value Nmgset, Ensures the required output according to the amount of accelerator depression. On the other hand, in the calculator 15, based on the engine intake air temperature Tl and the rotational speed Nmg, the gas generator corrected rotational speed N4*=Ngg/V
T, is calculated and calculated, and from this corrected rotation speed Nmg*, the second
Compressor turbine inlet correction temperature T7 as shown in the figure
Find set*.

Next, calculate T7set**Ti to obtain the compressor turbine inlet temperature command value T,set, and compare this with the actual value.
Subtractor 1 for the deviation from the compressor turbine inlet temperature Tl
8, and this deviation ΔTl is further calculated by the calculation circuit 20 (
(Usually proportional integral) and input the VN angle instruction value VNset.
get. By driving the actuator 22 according to this instruction value, the compressor gate turbine inlet temperature τ,
The VN angle α is changed to control the flow velocity direction of the high temperature gas to the power turbine so that the command value T,set is achieved, thereby preventing a surge in the copresor and controlling the engine efficiency favorably. By the way, from the viewpoint of heat resistance of the turbine, it is necessary to control the turbine inlet temperature T7 so as not to exceed a predetermined upper limit T7MAX.
4, the command value T7set and the upper limit T7MA8 are compared, the smaller value is selected, and this is set as the actual turbine inlet temperature command value T7setl.

However, such control has the drawback that when the engine intake air temperature T1 rises above normal, the maximum output of the engine decreases significantly.

In other words, the aerodynamic design of the engine is designed to be most efficient at room temperature, so at maximum output, VN
is set at an angle that facilitates output, and the compressor turbine inlet temperature T7 is set at an upper limit T7MAX. However, at the same rotational speed Ngg and VN angle, when the intake air temperature T1 increases, the inlet temperature T7 significantly increases due to the law of similarity of turbomachines. If the maximum load is requested from the engine at this time, the rotational speed Ngg will increase, but since the indicated value T7set will be larger than the upper limit T7MAX, VN will be forcibly opened, and as a result, the engine inlet temperature will simply increase. This causes a larger output drop than that caused by the increase in output. This situation will be specifically explained with reference to FIG.

Figure 3 shows that the engine inlet temperature, that is, the intake air temperature T1 is 35
The relationship between the gas generator rotational speed Ngg and the engine output at °C is shown as a VN angle parameter. The VN angle is from 1 to 00, which is the setting angle that produces the most output.
The case where the force is shifted by 10, 20 forces is taken as an example.

These are shown as solid lines in the figure, but as is clear from the figure, the output increases as the rotational speed N increases, and the VN
The smaller the deviation from the set angle. However, even if the rotational speed is the same, the output tends to increase relatively.

On the other hand, the relationship between the rotational speed Ngg and the output when the turbine inlet temperature T7 is fixed at 1000° C. by controlling the VN angle is shown by a dashed line in the figure.

As is clear from this dotted line, in this device,
When the turbine inlet temperature is fixed at 1000° C., the engine output is highest when the rotational speed Ngg is around 95% of the maximum rotational speed rather than at the maximum rotational speed (100%).

As is clear from the intersection of the dotted chain line and the solid line in the figure, at the point where this engine output increases the most, VN is exactly near the set angle, and even if the rotational speed N is increased beyond that, the As a result, the turbine inlet temperature tends to rise, so in order to keep the turbine inlet temperature the same, VN opens from the set angle, resulting in a large reduction in engine output.

The present invention has been made in view of the above, and it enables the engine to produce the maximum output that can be achieved according to the intake air temperature at that time, thereby reducing the maximum output due to the increase in the intake air temperature. The present invention provides a device that minimizes the decrease in output while maintaining engine safety.

This will be explained below with reference to the drawings.

FIG. 4 shows a first embodiment of the present invention, in which 30 is a function generator. The function generator 30 calculates the engine intake air temperature T
1, for example, T1 x K (constant), and uses this as the subtraction value N degrees d.
Output to.

In the subtracter 7, (instruction value Nggset - subtraction value Nggset
Since the deviation ΔNgg is obtained by calculating the number of rotations (Ngg), the apparent command value Ngg is corrected so that it becomes smaller in accordance with the rise in intake air temperature.

The other configurations are the same as those in FIG. 1, so the same parts are given the same reference numerals.

In this embodiment, even if a large output is requested by pressing the accelerator when the intake air temperature rises, the indicated value N
The fuel flow rate is automatically throttled by the amount that t has been corrected, and the rotation speed N is controlled to around 95% of the maximum rotation speed that provides the maximum output, as shown by the dotted chain line in Figure 3. The increase in intake air temperature is suppressed, and the ■N angle is maintained near the set angle. Therefore, even when the intake air temperature rises, it is possible to produce the maximum output that can be achieved according to the intake air temperature at that time, and when the large output that was generated due to the increase in the intake air temperature is requested. Forced output reduction can be minimized.

Therefore, as shown in FIG. 5, the output performance of the engine when maximum output is required when the intake air temperature rises can be significantly improved compared to the conventional device. Note that even when the output is not at maximum output, the rotational speed and output relative to the accelerator opening change relative to the intake air temperature, but during driving the intake air temperature (outside air temperature)
Since it is rare for the value to fluctuate significantly and rapidly, this does not cause the accelerator feeling to deteriorate significantly, and it can be said that there is almost no problem in practical use. FIG. 6 shows the main part of a second embodiment of the present invention. In this embodiment, a bimetal 5a is interposed in the engine intake passage, and a fixed resistor of a potentiometer 5c whose resistance value changes depending on the amount of depression of the accelerator pedal 5b is linked to the bimetal 5a.
, 5e, the engine intake air temperature T
In this example, the instruction value Nggset is corrected in accordance with 1. The rest of the structure is the same as that of the first embodiment, and this embodiment has the same effects as the first embodiment.

FIG. 7 shows a third embodiment of the present invention. In this embodiment, the selector 34 selects the smaller value from the upper limit N° MAX'' and the indicated value Nggset, and outputs this to the subtracter 7 as the actual indicated value Nggset. Therefore, by correcting the instruction value NSeV so that it does not exceed a predetermined upper limit, and by using the value obtained by subtracting the subtracted value Nggd from the predetermined upper limit NggMAX'' as the upper limit NggMAX'' by the subtracter 33, The indicated value Nggset'' is relatively corrected only when the accelerator is depressed the most and maximum output is requested.For this reason, when the accelerator is depressed the most (high output is required such as in an emergency), the indicated value Nggset'' is relatively corrected. The problem that the relationship between the accelerator position and the rotational speed of the gas generator differs depending on the intake air temperature T1 can be solved.

As explained above, the present invention corrects the command value regulating the fuel flow rate so that the engine can produce output most efficiently according to the intake air temperature, so even when the intake air temperature rises, The maximum output according to the intake air temperature can always be produced when the maximum output is requested, and the forced reduction in output when a large output is requested due to a rise in the intake air temperature can be minimized. .

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a conventional device, Fig. 2 is a characteristic diagram showing the relationship between corrected compressor turbine inlet temperature and corrected rotation speed, and Fig. 3 shows output characteristics when the engine intake air temperature is 35°C. FIG. 4 is a block diagram showing the first embodiment of the present invention, FIG. 5 is a characteristic diagram showing engine output characteristics with respect to intake air temperature in the conventional device and the device of the present invention, and FIG. Schematic diagram showing the main part of the second embodiment, No. 7
The figure is a block diagram showing a third embodiment of the present invention. 1...Engine, 5...Accelerator, 5a
...Bimetal, 5b...accelerator pedal, 5c...po. tensiometer, 5d, 5
e...Link, 7...Subtractor, 9...
... Arithmetic circuit, 11 ... Actuator, 15
... Arithmetic unit, 18 ... Subtractor, 20.
... Arithmetic circuit, 22 ... Actuator, 24.
...Selector, 30...Function generator, 33.
...Subtraction device.

Claims (1)

[Claims] 1. A gas generator shaft and a power turbine shaft that rotate independently of each other, a variable blade arranged at the power turbine inlet, and a fuel supply system that rotates the fuel in a direction that reduces the deviation between the indicated value based on the amount of accelerator depression and the gas generator shaft rotation speed. and means for variably controlling the angle of the blade in a direction to reduce the deviation between the compressor turbine inlet temperature and the indicated value based on the gas generator shaft rotation speed and engine intake air temperature. In an automobile gas turbine engine, a function generator outputs a value that increases according to intake air temperature, and an output value of the function generator is subtracted from an instruction value based on the accelerator depression amount and output as a fuel instruction value. An automobile gas turbine control device equipped with a subtracter.