JP2002070630A - Engine load adjustment device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine load adjustment device for a vehicle reducing a load on an air conditioning compressor, adjusting a load on a traveling engine, and keeping combustion of the traveling engine in a lean combustion state, when drive equipment except the compressor is driven. SOLUTION: In this load adjustment device, a lean combustion limit engine output corresponding to an engine speed is calculated, a total of the engine load concerning the traveling engine is calculated, the calculated limit engine output is compared with the calculated total, discharge capacity of the compressor is reduced to reduce the engine load below the limit engine output, and the drive equipment whose driving is required is driven. Thereby, the combustion of the traveling engine can be kept in the lean combustion state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling engine, an air conditioning compressor driven by the traveling engine and having a variable capacity mechanism, and at least one driven by the traveling engine together with the air conditioning compressor. The present invention relates to an engine load adjusting device for a vehicle having two driving devices, which adjusts a load applied to a traveling engine to improve fuel efficiency of the traveling engine.

[0002]

2. Description of the Related Art A vehicle engine (running engine), particularly a direct injection type engine, controls the amount of fuel supplied to obtain an engine output (torque) corresponding to the engine load. The combustion states include stratified (ultra-lean air-fuel ratio) combustion, homogeneous or uniform (lean air-fuel ratio) combustion, and stoichiometric (stoichiometric air-fuel ratio) combustion. Each combustion state, engine rotation speed Er, and engine output (torque) ) Eτ is
This is shown in FIG. As described above, if the fuel injection amount is increased to obtain a large engine output (torque), the combustion state changes from a stratified combustion state (As shown in FIG. 3) to a stoichiometric fuel state (Ast shown in FIG. 3). Since the fuel efficiency deteriorates, it is desirable that the combustion of the traveling engine be maintained in the stratified combustion state As as much as possible.

The vehicle air conditioner disclosed in Japanese Patent Application Laid-Open No. 5-139151 has an electric motor as a driving source of the compressor in addition to the driving engine so as to reduce the load on the driving engine when the vehicle is accelerated. During acceleration, the drive source of the compressor is switched from the traveling engine to the electric motor.

[0004]

However, the load of the traveling engine includes the basic load of the traveling engine itself and driving equipment using the traveling engine as a drive source, such as an air-conditioning compressor and a generator. There is a load, and the load on the traveling engine fluctuates when each driving device is driven by the traveling engine. Therefore, it is difficult to maintain the combustion of the traveling engine in a stratified combustion state.

Therefore, the present invention reduces the load on the air-conditioning compressor and adjusts the load on the traveling engine when driving equipment other than the air-conditioning compressor is driven. It is an object of the present invention to provide an engine load adjusting device for a vehicle which is kept at the same.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a traveling engine, an air conditioning compressor driven by the traveling engine and having a variable capacity mechanism, and driven by the traveling engine together with the air conditioning compressor. And a limit engine for calculating a lean burn limit engine output corresponding to a rotation speed of the traveling engine, and a basic engine corresponding to an actual rotation speed of the traveling engine. An engine load calculating means for calculating a load, an engine load by the air conditioning compressor and an engine load by the driving device; a lean burn limit engine output calculated by the limit output calculating means; and a lean burn limit engine output calculated by the engine load calculating means. A comparison means for comparing with the total engine load; When the comparing means determines that the total of the engine loads is larger than the lean burn limit engine output, the compressor load reducing means for reducing the discharge capacity of the compressor by a predetermined value; A driving device control means for driving the driving device when it is determined that the sum of the above is lower than the lean burn limit engine output.

Therefore, according to the present invention, the lean burn limit engine output corresponding to the engine rotational speed is calculated, and the total engine load of the driving engine is calculated. Since the discharge capacity of the compressor is reduced until the engine output drops below the combustion limit engine, and then the drive device requested to be driven is driven, the combustion of the driving engine can be maintained in a lean burn state and the compressor is stopped. Therefore, the operation of the air conditioner can be maintained.

Preferably, the driving device is a generator. With this configuration, when the battery power is insufficient, the load on the compressor can be reduced to drive the generator, so that the compressor and the generator are operated while maintaining the combustion of the traveling engine in the lean combustion state. Is what you can do.

Further, it is preferable that the lean combustion is stratified combustion or homogeneous combustion. Most preferably, the combustion of the traveling engine is stratified combustion. However, there is an advantage that a reduction in the load on the compressor can be suppressed by setting the combustion in a homogeneous combustion state.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

In the schematic configuration diagram shown in FIG. 1, a traveling engine 1 is, for example, a direct injection type engine, and is controlled by an engine control unit (ECU) 12.
The fuel injection amount is adjusted in consideration of the accelerator signal, the actual rotation speed Ers, and the like, and the rotation speed Er and the engine output (torque) Et are controlled.

The driving engine 1 is connected to driving devices such as an air-conditioning compressor 2 and a generator (alternator) 3 driven by the driving engine 1 via a belt or the like. The air conditioning compressor 2 constitutes a refrigeration cycle together with a condenser (radiator) 6, an expansion valve 9, and an evaporator 8 provided in an air conditioning duct 7 of the air conditioner, and is connected to the traveling engine 1 by an electromagnetic clutch 4. Is turned on and off to drive. Further, the air conditioning compressor 2 has a displacement variable mechanism 5 for varying the discharge displacement of the compressor. The alternator 3 includes a battery power source 10, a switch unit 11B, and a drive unit 11A.
Are connected via a relay switch 11 consisting of The drive unit 11A of the relay switch 11 can be controlled by the engine control unit 12 or the air conditioner control unit (ACU) 13, but is controlled by the air conditioner control unit 13 in the present embodiment.

In the relationship between the rotation speed Er of the normal running engine 1 and the engine output (torque) Eτ, a basic engine load τe is shown by a characteristic line L0 in FIG. On the other hand, when the electromagnetic clutch 4 is turned on and the compressor 2 is driven, and the discharge capacity is maximized by the capacity variable mechanism 5, the engine load by the compressor 2 is:
This is τcomp shown in FIG. 3, and the total engine load is shown by a characteristic line L1. The engine load generated when the alternator 3 is connected to the battery power source 10 is τalt shown in FIG. 3, and the total engine load is shown by a characteristic line L2. Further, the total engine load when the compressor 2 and the alternator 3 operate simultaneously is indicated by a characteristic line L3. From this, for example, at a predetermined engine rotational speed Ers, when only the basic engine load τe is used, or when the basic engine load τe and one of the compressor 2 and the alternator 3 are driven, the engine of the traveling engine 1 is driven. Since the output Eτ is in the stratified combustion region As, the driving engine 1 can be driven in a good fuel state, so that fuel efficiency can be improved and the state of exhaust gas can be kept good. However, the compressor 2 and the alternator 3
Are simultaneously driven to increase the engine load, the engine load Eτ changes from the stratified combustion region As to the homogeneous combustion region A.
h, and furthermore, the fuel economy deteriorates due to the shift to the stoichiometric combustion region Ast. Therefore, the load adjustment control according to the embodiment of the present invention is executed.

The engine control unit 12 and the air conditioner control unit 13 have a central processing unit (CPU) and a read-only memory (RO), respectively.
M), a known device having at least a random accelerator memory (RAM), an input / output port (I / O), etc., to which various signals are input. The input signals are processed by a predetermined program to control signals. And outputs each control signal to each control device.

The load adjustment control according to the embodiment of the present invention out of the programs executed in the engine control unit 12 or the air conditioner control unit 13 is, for example, shown in the flowchart of FIG.

Then, at step 110, the rotational speed Er of the traveling engine 1, the engine output Eτ, the voltage Vbt of the battery power source, the high pressure detection sensor 1 of the refrigeration cycle
High pressure Pd, low pressure detection sensor 1
5, various setting signals including a low-pressure pressure Ps, an evaporator temperature Te, an outside air temperature Ta, a vehicle interior temperature Tr, a solar radiation amount Qs, and a temperature setting signal Ts from an operation panel (not shown) are read. And step 12
0, the engine rotation speed Er and the engine output Eτ
Is calculated from what combustion zone the combustion point Bp of the traveling engine 1 is in [Bp = P (Er, Eτ)].

Based on the result of this calculation, step 130
In, the determination of the combustion zone is performed. In this determination, when it is determined that the combustion point Bp is located in the stratified combustion region As (B), the process proceeds to step 140, and when it is determined that the combustion point Bp is not located in the stratified combustion region As (A),
Proceeding to step 220, normal control is set, and step 2
The process proceeds from 30 to another control routine. In this case, it is necessary to adjust the load because the combustion state of the traveling engine 1 has already deviated from the stratified combustion region due to the acceleration state of the traveling engine 1, the climbing state of the vehicle, and the driving by other driving devices. There is no one.

In step 140, it is determined whether the battery voltage Vbt is lower than a predetermined voltage α. That is, in this determination, it is determined whether or not the alternator 3 needs to be driven. In this determination, if the battery voltage Vbt is equal to or higher than the predetermined voltage α (N), there is no need to drive the alternator 3, so the routine proceeds to step 220 and normal control is set, and Proceed to another control routine.

If it is determined in step 140 that the battery voltage Vbt is higher than the predetermined voltage α (Y), the process proceeds to step 150 to determine whether the compressor 2 is operating. In this determination, the compressor 2
If is not operating (N), the routine proceeds to step 210, where the relay switch 11 is turned on (R ON), and the battery power (B / T) 10 is charged by the alternator 3. In this case, since the compressor 2 is not operating, the characteristic of the traveling engine 1 is L2 shown in FIG. 3, so that the combustion point Bp of the traveling engine 1 is held in the stratified fuel region As. .

If it is determined in step 150 that the compressor 2 is operating (Y), the routine proceeds to step 160, where the upper limit of the stratified combustion region corresponding to the engine speed Ers at that time is determined. Output τ
el is calculated. This is, as shown in FIG. 3, a characteristic line L4 indicating the relationship between the rotational speed Er and the upper limit of the stratified fuel region.
May be calculated on the basis of the above, or may be calculated by calculation.

Then, the routine proceeds to step 170, where the calculation of the total engine load τload is performed. The total engine load τload is obtained by calculating the engine load τalt (generally a fixed value) of the alternator 3 and the engine load τcomp of the compressor 3 (τcomp = A · F (P
d) + BF (Ps) + CF (Cc) + D) and basic engine load τe (τe = EF (Er) + G: characteristic line L
0) (τload = τe + τcom)
p + τalt).

In step 180, the magnitude of the upper limit output τel is compared with the engine load τload. As a result, when it is determined that the engine load τload is large (N), the process proceeds to step 190,
It is determined whether or not the discharge capacity Cc of the compressor 2 is the minimum value min. If the discharge capacity Cc is not the minimum value min (N), the process proceeds to step 200, where the discharge capacity Cc is reduced by a predetermined value β. , From step 230 to another control routine. As a result, when the control enters next, since the engine load τcomp by the compressor 2 is reduced in the calculation of step 170, the total engine load τload is reduced, and the determination of step 180 is reached. If it is determined in step 180 that the engine load τload is large again, the above-described control is repeated, and the total engine load τload is gradually increased.
Decrease. As a result, if the engine load τload is lower than the upper limit output τel (Y), the routine proceeds to step 210, where the relay switch 11 is turned on (RO).
N), and the battery power supply 10 is charged. However, the combustion state of the engine 1 is maintained in a stratified combustion state, so that deterioration of fuel efficiency can be prevented, and further, the operation of the refrigeration cycle can be continued. The deterioration of the ring can be suppressed.

If it is determined in step 190 that the discharge capacity Cc of the compressor 2 has reached the minimum value min, the routine proceeds to step 210, where the relay switch 11 is turned on. In this case, since the alternator 3 is driven by minimizing the discharge capacity Cc of the compressor 2 and minimizing the engine load by the compressor, the combustion of the traveling engine 1 deviates from stratified combustion. Since the level can be minimized,
Fuel efficiency can be improved.

Further, in the above-described embodiment, the upper limit value τel of the engine output is calculated based on the characteristic line L4 indicating the upper limit value of the stratified combustion, but the characteristic line L5 indicating the upper limit value of the homogeneous combustion is calculated. The calculation may be performed based on this. In this case, since the operation limitation of the compressor 2 can be relaxed as compared with the above-described embodiment, the fuel efficiency of the traveling engine 1 becomes worse as compared with the above-described embodiment, but the cooling power due to the refrigeration cycle decreases. Therefore, the air conditioning level can be maintained.

[0025]

As described above, according to the present invention, it is possible to adjust the engine load of the driving device applied to the driving engine to minimize the operation of the driving engine in the stoichiometric combustion region. It is possible to achieve an improvement in fuel efficiency. Specifically, when power generation is required during operation of the air conditioner, the power of the air conditioner is limited to generate power, so that the combustion state of the driving engine can be maintained in a lean combustion state, thereby improving fuel efficiency. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing an embodiment of the present invention.

FIG. 3 is a characteristic diagram illustrating a relationship between an engine rotation speed and an engine output and each combustion region and illustrating a state of each engine load.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Running engine 2 Compressor for air conditioning 3 Generator (alternator) 4 Electromagnetic clutch 5 Variable capacity mechanism 10 Battery power supply 11 Relay switch

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 29/06 F02D 29/06 L H02P 9/04 H02P 9/04 L (72) Inventor Kazuhiro Irie Saitama 39, Higashihara, Chiyo-ji, Odai-gun, Osato-gun, F-term (reference) 3G084 AA04 BA02 BA34 BA35 CA03 DA02 EB12 EB16 EC03 FA02 FA03 FA31 FA33 3G093 AA01 AA12 AA16 BA19 CA06 DA01 DB09 DB19 DB25 DB06 EA EB09 EC02 EC04 FA01 FA03 FA06 FA08 FA11 FA12 5H590 AA02 CA07 CA23 CC01 CE05 FA01 FA05 FC25 GB05 HA02 HA15 HA18 HA27 JA02 JB02

Claims (4)

[Claims] 1. A vehicle comprising a traveling engine, an air conditioning compressor driven by the traveling engine and having a variable capacity mechanism, and at least one drive device driven by the traveling engine together with the air conditioning compressor. A limit output calculating means for calculating a lean burn limit engine output corresponding to a rotational speed of the traveling engine; a basic engine load corresponding to an actual rotational speed of the traveling engine; an engine load by the air conditioning compressor; Engine load calculating means for calculating an engine load by the driving device; comparing means for comparing a lean burn limit engine output calculated by the limit output calculating means with a total of the engine load calculated by the engine load calculating means. And the comparing means, If the total load is determined to be larger than the lean burn limit engine output,
A compressor load reducing unit configured to reduce a discharge capacity of the compressor by a predetermined value; and the comparing unit determines that a total of the engine loads is lower than a lean burn limit engine output.
An engine load adjusting device for a vehicle, comprising: a driving device control unit that drives the driving device. 2. The apparatus according to claim 1, wherein the driving device is a generator. 3. The engine load adjusting device according to claim 1, wherein the lean combustion is stratified combustion. 4. The engine load adjusting device for a vehicle according to claim 1, wherein the lean combustion is a homogeneous combustion.