JPH05118233A - Engine output characteristic changeover shock reducing device - Google Patents

Abstract

PURPOSE:To reduce changeover shock of engine output charateristic by performing changeover of engine output characteristic when transmission passage is cut off during operating changeover of gear shift steps of a manual transmission. CONSTITUTION:An output characteristic changeover judging means judges whether changeover of engine output characteristic is necessary or not, and a transmission passage cutoff detecting means detects that transmission passage between the engine and transmission output shaft is cut off. An output charateristic changeover delaying means delays execution thereof till cutoff of transmission passage, and changeover of engine output characteristic is performed in synchronization with the cutoff of the transmission passage when changeover of engine output characteristic is judged necessary. Accordingly, shock according to changeover is never reaches a transmission output shaft, and this shock can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for reducing engine output characteristic switching shock in a power train in which a variable output characteristic engine and a manual transmission are connected in tandem.

[0002]

2. Description of the Related Art As an output characteristic variable engine, for example, as described in Japanese Patent Laid-Open No. 3-111610, the output characteristic with respect to the throttle opening is switched by not using only one type of intake and exhaust valves of the engine but by properly using a plurality of cams. There is known a so-called variable valve type engine which is adapted to obtain the above. This engine is provided with three types of cams for each intake and exhaust valve, and these cams, that is, fuel economy cams (hereinafter referred to as P-cam A low-speed cam (hereinafter referred to as L-cam) useful at low speed and a high-speed cam (hereinafter referred to as H-cam) useful at high speed based on engine drive load and engine speed. It is used properly to match the condition. Depending on this selection, the engine is used when the P-cam is used and when the L-cam is used, as shown in FIG.
The output characteristics can be switched when the H cam is used.

[0003]

By the way, in the variable output characteristic engine represented by the engine as described above, when the output characteristic (cam) is switched at a point other than the equal torque point indicated by E in FIG. , There is a step in the torque, causing a switching shock. For example, when switching to H cam or L cam during engine operation at F point using P cam,
The engine output shaft torque sharply increases to the G point or H point, and conversely, the engine output shaft torque sharply decreases when switching to the P cam. In such a power train in which the engine and the manual transmission are tandemly coupled, the manual transmission does not have a torque fluctuation absorbing element such as a torque converter in the transmission system as in the automatic transmission. The characteristic switching shock is transmitted from the engine to the wheels as it is, and the passenger feels this shock greatly, which is not preferable.

The present invention solves the above problems by synchronizing the switching of engine output characteristics with the temporary interruption of the transmission system between the engine and the output shaft of the transmission that occurs during the gear shift operation of the manual transmission. To aim.

[0005]

To this end, an output characteristic switching shock reducing device of the present invention has a variable output characteristic engine for switching and using a plurality of output characteristics with respect to a throttle opening, as shown in the concept of FIG. In a power train that is tandem-coupled with a manual transmission that uses a plurality of gears for manual switching, output characteristic switching determination means for determining whether or not engine output characteristics need to be switched, and transmission between the engine and the transmission output shaft. When the transmission path cutoff detection means for detecting the disconnection of the path and the output characteristic switching judgment means judge the necessity of switching the engine output characteristics, the transmission path cutoff detection means detects the cutoff of the transmission path. And an output characteristic switching delay means for delaying the switching of the engine output characteristic and synchronizing this switching with the interruption of the transmission path. It is constructed by providing.

[0006]

The engine outputs power according to the selected output characteristic, and this engine power is extracted by the manual transmission at a gear ratio corresponding to the selected gear.

Meanwhile, during this period, the output characteristic switching determination means determines whether or not the engine output characteristic needs to be switched, and the transmission path cutoff detection means detects that the transmission path between the engine and the transmission output shaft is cut off. Then, in response to the signals from these means, the output characteristic switching delay means delays the execution until the transmission path is cut off when it is determined that the engine output characteristic needs to be switched. Therefore, the switching of the engine output characteristic is always performed in synchronization with the interruption of the transmission path, and the shock associated with the switching does not reach the transmission output shaft, and this shock can be reduced.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 shows one embodiment of the engine output characteristic switching shock reducing apparatus according to the present invention, in which 1 is an engine, 2 is a manual transmission, and this apparatus is a tandem power train. Shall be reduced.

The engine 1 burns the injected fuel by the air sucked from the air cleaner 3 through the throttle valve 4, inputs the output thus obtained into the manual transmission 2, and outputs the combustion exhaust gas from the exhaust pipe 5 to the outside. To release. By the way, the throttle valve 4 of the engine 1 is mechanically connected to an accelerator pedal (not shown) operated by the driver, and the driver adjusts the engine output by adjusting the intake air amount according to the accelerator pedal depression amount. An intake / exhaust valve for adjusting the intake and exhaust to the engine speed is shown in Fig. 4.
5, a variable valve as described in Japanese Patent Application Laid-Open No. 3-111610 as described above, and a cam switching mechanism 7 that responds to the cam switching control valve 6 to switch the three types of cams.
Shall be carried out by

The manual transmission 2 changes the rotational power from the engine 1 at a gear ratio corresponding to the selected gear and transmits it to the output shaft 8 to drive the wheels of the vehicle, for example. And That is, the clutch pedal 9
When the clutch 10 is released by depressing, the transmission output shaft 8 is disengaged from the engine 1. In this state, the driver operates the transmission lever 11 to a desired position to put the manual transmission 2 into the corresponding shift stage. be able to. After that, the clutch pedal 11 is released to connect the clutch 10 so that the engine power can be transmitted to the transmission output shaft 8 and the vehicle can travel at the gear. The disconnection between the engine 1 and the transmission output shaft 8 can also be obtained by setting the shift lever 11 of the clutch 10 to the neutral position.

However, in this example, the control valve 6 of the engine 1 is
Cam switching control (control command CAM) via the engine controller 12 together with other engine controls.
For that purpose, the engine operating information such as the engine speed Ne is input to the controller 12 from the engine 1 and the running state of the vehicle is input, and the signal from the clutch switch 13 that is turned off when the clutch pedal 9 is depressed is input. To do. Clutch switch 13 is off
The disconnection between the engine 1 and the transmission output shaft 8 is detected by, and this disconnection can also be detected by the neutral switch 14 that is turned on by detecting the neutral position of the transmission lever 11.

The engine controller 12 executes the control program shown in FIG. 3 on the basis of these input information, and the output characteristic switching timing control (cam switching timing control) for reducing the engine output characteristic (cam) switching shock aimed by the present invention. Shall be realized.

That is, first, at step 21, the most suitable cam for the present condition is determined from the engine operating state such as the engine speed Ne and the vehicle running state. In the next step 22, it is checked whether or not switching of the cam is necessary depending on whether or not this optimum cam is different from the currently selected cam (command CAM). If it is necessary, step 2
It is checked in step 3 whether the clutch switch 13 is ON or OFF, that is, whether the transmission path between the engine 1 and the transmission output shaft 8 is formed or cut off. Only when the transmission path is cut off, step 24 Then, the signal CAM to the cam switching control valve 6 shown in FIG. 2 is changed to the optimum cam and a cam switching command is issued.

Therefore, even if it is determined that the cam needs to be switched, this switching is not executed while the transmission path between the engine 1 and the transmission output shaft 8 is formed, and is delayed until the transmission path is interrupted. It is carried out in synchronization with this interruption. Therefore, the shock associated with the switching of the cam is not transmitted to the transmission output shaft 8, and the shock can be reduced. Needless to say, in step 23, when checking whether the transmission path between the engine 1 and the transmission output shaft 8 is cut off, it may be checked whether the neutral switch 14 in FIG. 2 is OFF. Yes.

[0015]

As described above, the device of the present invention delays the switching of the engine output characteristic (cam in the illustrated example) until the transmission path between the engine and the transmission output shaft 8 is cut off. Since the configuration is performed in synchronism with the cutoff, the shock that is generated due to the switching of the engine output characteristic does not reach the transmission output shaft 8, and the output characteristic switching shock can be reduced.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an engine output characteristic switching shock reducing device of the present invention.

FIG. 2 is a schematic diagram of a power train and its control system showing an embodiment of the present invention.

FIG. 3 is a flowchart showing a control program executed by the controller of the same example.

FIG. 4 is an operational characteristic diagram of three types of intake / exhaust valve cams.

FIG. 5 is an output performance diagram of the engine according to the proper use of the cam.

[Explanation of symbols]

 1 Engine 2 Manual transmission 3 Air cleaner 4 Throttle valve 5 Exhaust pipe 6 Cam switching control valve 7 Cam switching mechanism 8 Transmission output shaft 9 Clutch pedal 10 Clutch 11 Shift lever 12 Controller 13 Clutch switch 14 Neutral switch

Claims (1)

[Claims] 1. A power train having a tandem combination of an output characteristic variable engine that switches and uses a plurality of output characteristics with respect to a throttle opening and a manual transmission that manually switches and uses a plurality of shift speeds. Output characteristic switching determination means for determining whether switching is necessary, transmission path cutoff detection means for detecting that the transmission path between the engine and the transmission output shaft is cut off, and the output characteristic switching determination means for determining the engine output characteristics When determining the necessity of switching, there is provided output characteristic switching delay means for delaying the switching of the engine output characteristic until the transmission path cutoff detection means detects the cutoff of the transmission path and synchronizing the switching with the cutoff of the transmission path. A shock mitigation device for switching engine output characteristics, which is provided.