JPH0138174B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an output control method and device for a vehicle tower-mounted diesel engine, and in particular an output control method that can reduce the frequency of gear change operations when climbing hills and at the same time make climbing easier. and devices.

The most energy-efficient prime movers for vehicle towers are DC series-wound motors, which have torque characteristics such that the lower the speed, the higher the torque, and the higher the speed, the lower the torque, but generally internal combustion engines are the most energy efficient. does not have the above-mentioned torque characteristics, and therefore vehicles equipped with an internal combustion engine must be equipped with a large transmission. However, if the equipped transmission is not a continuously variable transmission, the output torque cannot be changed continuously, so the output torque between each gear changes in steps, and as a result, the running of the vehicle is affected. There are problems in that it cannot be performed smoothly, it is difficult to select the driving torque most suitable for the vehicle's running, and frequent gear shifting operations are required.

FIG. 1 shows one such example, in which the horizontal axis represents the traveling speed V of the vehicle, and the vertical axis represents the driving force T generated by the transmission output shaft. Further, is the driving force curve at the first speed of the transmission, similarly is the driving force curve at the second speed, and ~ is the driving force curve at the third, fourth, and fifth speeds (highest speed), respectively. As can be seen from this figure, the driving force curves at each gear stage are far apart from each other except for between 4th and 5th gears, so for example, the running resistance of the vehicle is between T ₂ and T ₃ . If the value of . This phenomenon is especially common when climbing hills. For example, if a vehicle climbing a slope in third gear is decelerated due to an increase in running resistance and the vehicle speed becomes further lower than speed V ₂ , the running resistance of the vehicle at that time will be between T ₂ and T ₃ . Even in this case, the driver must downshift to second gear and further depress the accelerator pedal to accelerate. In order to suppress such wasteful fuel consumption and eliminate the need for frequent gear shifting operations, it would be better if the driving force change of the transmission output shaft formed a continuous curve like the two-dot chain line A in Fig. 1. Such a change in driving force can only be realized by a continuously variable transmission such as a torque converter.

Therefore, in order to achieve driving force characteristics similar to the driving force variation A described above using a manual transmission, it is necessary to use a multi-speed transmission with as many as 10 gears, or to change the output of the engine itself. It is necessary to improve the torque characteristics, but the former method, that is, the method using a multi-speed transmission, has the disadvantages of increasing the number of gear shifting operations and significantly increasing the weight of the transmission, and is not desirable. Since this consumes unnecessary fuel, it is better to reduce the number of gear shifts. Therefore, if the torque characteristics of the transmission output shaft can be approximated to the characteristic A described above by improving the output characteristics of the engine body, it will be possible to reduce the number of gear shifting operations, improve wasteful fuel consumption, and achieve smooth running. It should be possible.

Figure 2 shows the conditions necessary for the above purpose as changes in the torque of the transmission output shaft, where T〓 is the change in the output torque of the 2nd speed, and T〓 is the output torque of the 3rd speed. Each represents a change. The conditions for these torque changes to approach characteristic A are (i) the torque fluctuation (torque rise) T _R at each gear is large, and (ii) the maximum torque at each gear and the torque at the previous gear are large. It is necessary that the difference ΔT from the minimum torque is as small as possible and that they are on substantially the same vehicle speed line, and (iii) that the vehicle speed range V _R at each gear stage is large.
In addition, from the viewpoint of operability and economy, (a) avoidance of the use of expensive torque converters with low transmission efficiency, and (b) manual multi-speed transmissions (at least 10 or more speeds). It is clear that in order to satisfy (i) to (iii) above, it is necessary to improve the output characteristics of the engine itself rather than the transmission structure. . In particular, conventional diesel engines (regardless of whether they are non-supercharged or supercharged) do not have torque characteristics that increase torque in the lower speed range in order to meet the above requirements, so this needs to be improved. It was hot.

FIG. 3 is a part of a vehicle running performance diagram for explaining the purpose and principle of the present invention. In the figure, the horizontal axis represents the vehicle speed V, and the vertical axis represents the driving force T of the transmission output shaft.
, respectively. Also, the solid curve
For example, it is assumed that C ₁ represents a change in output torque at the 5th speed of a manual six-speed transmission, and a solid curve C ₂ represents a change in output torque at the 6th speed of the same transmission. (Generally, a power unit consisting of a combination of a manual 5- or 6-speed transmission and a diesel engine has such driving force torque characteristics.) A vehicle equipped with a power unit having the driving force characteristics as shown in the figure. For example, when the vehicle is in the sixth gear and the road slope becomes steeper while climbing a hill with full load, the vehicle speed V begins to decrease, and the driving force increases along the curve _C2 in the direction of the arrow a as the vehicle speed decreases. If the vehicle speed reaches V〓 and the load resistance is still greater than the propulsion shaft driving force, the driver must downshift the transmission to 5th gear at vehicle speed V〓 to increase the driving force. However, if the load resistance at that time is an intermediate value between the minimum driving force in 5th gear and the maximum driving force in 6th gear, the increased driving force is applied to the propulsion shaft by shifting down, and the vehicle speed is increased again. can be increased. However, this is undesirable because extra fuel is consumed when downshifting. Therefore, in the present invention, in order to eliminate the need for such a downshift, the propulsion shaft driving force curve during full load running at a predetermined gear stage is connected to the driving force curve at the previous stage, for example as shown in B. The aim is to increase the engine-generated torque itself toward lower speeds. Therefore, according to the present invention, the amount of fuel supplied, which has heretofore been adjusted independently of the transmission, is changed in conjunction with the transmission, making it possible to control the output in accordance with the driving conditions. Further, according to the output control method of the present invention, the torque rise in the transmission becomes large, and driving performance similar to that of a continuously variable transmission vehicle can be obtained even with a manual transmission with a relatively small number of gears. Frequent gear shifting operations are no longer necessary, resulting in reduced fuel consumption and economical driving.

FIG. 4 is an engine torque diagram showing the principle of the method of the present invention, in which the vertical axis shows the torque generated by the engine, and the horizontal axis shows the engine rotation speed. Further, in the figure, a solid curve Co is a full-load torque curve of a commonly used engine. In addition, the curve Cx is a curve representing the full-load torque characteristics generated by the engine in the 5th gear of a manual 6-speed transmission, and the Cy curve is a curve that represents the full-load torque characteristics generated by the engine when the same transmission is operated in the 6th gear. This is a curve representing the full load torque characteristics. Curves Cx and Cy are generated by the engine by the output control device of the present invention only when the vehicle is running. The running torque in the low speed range is greater than that of the conventional engine by an amount C, and therefore, B in Fig. 3
It is possible to achieve the following propulsion shaft torque characteristics.

Next, embodiments of the present invention will be described with reference to FIGS. 5 to 8.

FIGS. 5 to 8 show an embodiment of an apparatus for carrying out the method of the present invention. The device of the invention shown in the embodiment of the figure includes a control rack regulator 2 for controlling the control rack of a fuel injection pump 1, a controller 3 for controlling the control rack regulator 2, a control rack regulator 3 for controlling the control rack regulator 2, and a control rack regulator 3 for controlling the control rack regulator 2. Vessel 3
It consists of devices such as an engine speed detector 4 and a transmission (not shown) operating position detector 5, which are electrically or mechanically connected to the engine. In FIG. 5, 7 is a known governor, 8 is a timer, 9 is a control lever, and 10 is an operating rod.

The control rack adjuster 2 is shown in FIGS. 6 to 8.
As shown in the figure, it is attached to the opposite end of the fuel injection pump 1 from the governor device side.
A control rack adjusting member 12 is provided within the casing 11 and is aligned with the control rack 1A of the fuel injection pump 1. A cylinder 13 for moving the control rack adjusting member 12 in the axial direction is attached to the casing 11, and the control rack adjusting member 12 and the piston rod 1 of the cylinder 13 are installed inside the casing 11.
4 is pivotally connected to the lever 15. A split sleeve 16 for guiding the control rack adjusting member 12 is provided within the casing 11, and a lid plate 17 for pressing the split sleeve 16 is fastened to the casing 11. A movable stopper 18 for adjusting the most retracted position of the control rack adjusting member 12 is screwed into the cover plate 17.

In this embodiment, a control rack adjuster 2 is used to change the maximum fuel supply position of the control rack 1A (the left position in FIG. The control rack 1A, which is operated toward the left in FIG. 6 (in the fuel increasing direction) via the governor 7,
2, maximum fuel supply is supplied to the engine (not shown).

Next, the operation of each part of the apparatus configured as described above will be explained, and at the same time, the relationship between the apparatus and the method of the present invention will be explained with reference to FIG. (In the following explanation, it is assumed that the transmission mounted on the vehicle is, for example, a 6-speed manual transmission, but any manual transmission may be used, and the number of stages is a particularly limited element in the present invention. ) When the engine is operating at full load and the transmission is not in a specifically designated gear, the control rack adjustment member 12 is positioned at position x ₀ in FIG.
Even if the control rack 1A is operated in the maximum fuel increasing direction (to the left), it will hit the control rack adjustment member 12 at this position _x0 ,
No more fuel is supplied to the engine. this position
The full load torque characteristic curve of the engine at x ₀ is shown in Figure 4.
Co. When the transmission (not shown) is running in a specially designated gear, for example 5th gear, the engine speed reaches Ne _1.
When the operating position detector 5 moves downward, a signal is sent to the controller 3 from the operation position detector 5, and the controller 3 controls the cylinder 13 to adjust the control rack adjusting member 12, for example.
Move it backward to a position to the left of x ₀ , so that when the control rack 1A is held, it is propelled in the direction of increasing fuel.

When the accelerator pedal is fully depressed in this state, the control rack adjustment member 12 moves back to position x ₁ in FIG. 6 and stops, and when the control rack 1A is propelled to its maximum fuel position,
A fuel injection pump supplies fuel to the engine (not shown) such that a torque characteristic of Cx is generated from the engine. However, when the engine speed exceeds Ne ₁ , the controller 3 pushes the control rack adjusting member toward the right in FIG. 6, reducing the fuel supply to the engine, and as a result, the torque characteristics of the engine change. Control the fuel so that it rides the original Co.

Therefore, for example, during full load climbing in 5th or 6th gear, the engine speed decreases and Ne ₁ or
When the speed drops below Ne ₂ , the torque generated by the engine increases just by pressing the accelerator pedal, so there is no need to downshift the transmission, making driving easier and reducing the increase in fuel consumption due to downshifting. It can be prevented.

FIG. 9 shows another embodiment of the present invention, in which a supercharging device 19 is added to make the engine generated torque in the low engine speed range larger than the torque in the high speed range. . This supercharging device 19 also serves as a part of a conventional air brake device, and includes a compressor 20 for air brakes and an air reservoir 21, and further connects the air reservoir 21 and the intake pipe 23 of the engine 22. It has a supercharging pipe 24 and a supercharging valve 25 provided in the supercharging pipe 24. The supercharging valve 25 is a flow rate control and pressure regulating valve that is opened and closed by the controller 3, and when the supercharging valve 25 is opened, the engine 22 is supercharged. Supercharging valve 2
5 indicates that the engine speed is Ne ₁ or
It is opened when the vehicle is running with the transmission in the 5th or 6th gear when the engine speed is below ₂ , and is controlled by the controller 3 so that the degree of opening increases as the engine speed decreases. Ru. And the engine speed is Ne ₁
Otherwise, it is closed during operation at Ne ₂ or higher, and the only air taken into the engine is the intake air S from the air cleaner, and the engine 22 is operated without supercharging. Therefore, the full load torque curve of the engine becomes as shown in FIG.

(In order to reduce the power consumption of the compressor 20, a separate compressor is provided that utilizes the exhaust energy of the engine 22, and an auxiliary air reservoir is provided to recover the exhaust energy when the engine rotates at high speed as compressed air. ) The above is an example for variable control of the maximum fuel supply amount under full load, but even under partial load, it is possible to increase the generated torque in the medium and low speed range more than the generated torque in the high speed range. Conventional governors are unsuitable for this purpose, and the control rack regulator 2 of the present invention must be used in place of the conventional governor.

The embodiment shown in FIG. 10 shows an example in which the control rack regulator 2 described above is used in place of the conventional governor. In this example, as shown in FIG. 11, the control rack adjustment member 12 is connected to the control rack 1A, and the controller 3 has an accelerator pedal operation amount detector 6 for detecting the amount of rotation of the accelerator pedal 26. An output signal is adapted to be applied. Therefore, when the engine speed becomes lower than a predetermined speed while driving at an arbitrary gear, the controller 3 controls the opening degree of the supercharging valve 25 according to the amount of depression of the accelerator pedal 26, and also controls the control rack adjustment member. 12 to control the amount of control rack operation.

The embodiment shown in FIG. 12 shows an example in which the method of the present invention is applied to an exhaust turbocharged engine. In this embodiment, a low-speed range supercharging device 19A having the same configuration as the supercharging device of the embodiment shown in FIG. The engine 27 is connected to the intake pipe 23 via a pipe 28. The compressor discharge port of the high-speed range supercharger 27 is also connected to the suction side of the compressor 20 of the low-speed range supercharger 19A via a branch pipe 29. A supercharging valve 30 is provided in the pipe 28, and the valve 30 is controlled by the controller 3.

In the above configuration, when the engine 22 is in a low speed range, the supercharging valve 25 is opened and the supercharging valve 30 is also opened, but when the engine is in a high speed range, only the supercharging valve 30 is opened. Further, since the flow rate and pressure of the supercharging valve 25 are set higher than the flow rate and pressure of the supercharging valve 30, the degree of supercharging in the low engine speed range is higher than the degree of supercharging in the high speed range. Part of the exhaust gas recovery energy when the engine is running at high speed is used to directly supercharge the engine, but the rest is stored as replenishment energy to the low speed range supercharger 19A and the air brake system. Therefore, the torque generated in the low speed range can be made larger than the torque generated in the high speed range, and the torque characteristics of the engine and the torque characteristics of the vehicle's propulsion shaft can be changed to Cx and Cy in Fig. 4 and B in Fig. 3. The characteristics can be as follows.

As described above, according to the present invention, it is possible to control a diesel engine mounted on a vehicle to an output state that is suitable for the running of the vehicle, thereby reducing the frequency of gear change operations, for example when climbing a slope, and reducing fuel consumption. can be achieved.

[Brief explanation of drawings]

Figure 1 is a running performance diagram showing the relationship between the vehicle's propulsion shaft driving force and vehicle speed, Figure 2 is a diagram showing the characteristics necessary for the propulsion shaft driving force, and Figure 3 is the same as Figure 2. FIG. 4 is a diagram for explaining the characteristics of the propulsion shaft driving force obtained by the method and device of the present invention, and FIG. 4 shows the torque of the vehicle tower engine achieved by the method and device of the present invention. Diagrams showing characteristics, FIGS. 5 to 8 are schematic diagrams of the first embodiment of the device of the present invention, FIG. 6 is an enlarged vertical sectional view of a part of FIG. 5, and FIG.
The drawings are a cross-sectional view taken along the - arrow in FIG. 6, FIG. 8 is a plan view of a part of FIG. 6, FIG. 9 is a schematic diagram of a second embodiment of the apparatus of the present invention, and FIG. FIG. 11 is an enlarged vertical sectional view of a portion of FIG. 10, and FIG. 12 is a schematic diagram of a fourth embodiment of the device of the present invention. 1; Fuel injection pump, 1A; Control rack, 2; Control rack regulator, 3; Controller, 4; Engine speed detector, 5; Transmission operation position detector, 6; Accelerator pedal operation amount detector, 19 ;Supercharging device, 20;Compressor, 21;Air reservoir, 25;
Supercharging valve, 19A; low speed range supercharger, 26; acceleration pedal, 27; high speed range supercharger, 30; supercharging valve.

Claims (1)

[Scope of Claims] 1. A method for controlling the output of a diesel engine installed in a vehicle, which detects the gear position of the vehicle's transmission in use, detects the rotational speed of the engine, and controls the output of the diesel engine when the gear position is used. In a region where the rotation speed is below a predetermined rotation speed, the fuel supply amount is specially increased, and thereby the fuel supply system of the engine is controlled so that the engine generated torque in the region becomes larger than the engine generated torque outside the region. A method for controlling the output of a vehicle-mounted diesel engine, characterized in that: 2. A control rack adjuster for positioning the control rack of the fuel injection pump, a transmission operation position detector for detecting the gear position of the vehicle transmission, and an engine rotation speed detector for detecting the engine rotation speed; The control rack is positioned at a predetermined position via the control rack adjuster in response to a signal from the transmission operation position detector, and at the same time, the control rack is moved in a region where the engine rotation speed is below a predetermined rotation speed. An output control device for a diesel engine mounted on a vehicle, comprising: a controller for positioning in a fuel increasing direction from a position corresponding to a region other than the above region.