Engine testing apparatus

Details Engine testing apparatus Engine testing apparatus

2000-04-26

2003-10-21

Williams, Hezron (Department: 2855)

Measuring and testing

Test stand

For engine

C073S117020

Reexamination Certificate

active

06634218

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to an engine testing apparatus.
DESCRIPTION OF THE PRIOR ART
As an apparatus for checking performance of an automobile engine, there exists an engine testing apparatus comprising a dynamometer connected to an output section of an engine under test, a dynamo controller for controlling the dynamometer, and an actuator for controlling a throttle opening degree of the engine under test. The engine testing apparatus controls the dynamo controller and the actuator to adjust the output of the engine under test.
FIG. 3
schematically shows a general structure of the engine testing apparatus. In
FIG. 3
, reference numeral
1
represents an engine under test and reference numeral
2
represents a dynamometer. An output shaft
1
a
of the engine
1
and a driving shaft
2
a
of the dynamometer
2
are coupled to each other through a clutch
3
such that the shafts
1
a
and
2
a
can be connected to and disconnected from each other. Reference numeral
4
represents a clutch actuator for driving the clutch
3
. Reference numeral
5
represents a throttle of the engine
1
under test, and the throttle
5
is driven by a throttle actuator
6
and its throttle opening degree is controlled. Reference numeral
7
represents a dynamo controller for controlling the dynamometer
2
. Reference numeral
8
represents a torque sensor mounted to the driving shaft
2
a
of the dynamometer
2
, and reference numeral
9
represents a torque amplifier for appropriately amplifying the output of the torque sensor
8
.
Reference numeral
10
represents a control computer as a simulator for controlling the entire apparatus, and reference numeral
11
represents a signal conditioner unit. The computer
10
performs a computation based on an input from an input apparatus (not shown) and based on signals from various sensors such as the torque sensor
8
provided in the apparatus, and outputs commands to various portions of the apparatus. For example, a target vehicle speed pattern
12
shown in
FIG. 3
, a target vehicle speed pattern
12
a
shown in FIG.
4
(A) or a target vehicle speed pattern
12
b
shown in
FIGS. 2 and 6
are inputted to the computer
10
. That is, in each of the target vehicle speed patterns
12
,
12
a
and
12
b
, the horizontal axis shows time (second) and vertical axis shows speed (km/h), and these patterns are target running patterns of desired driving.
The signal conditioner unit
11
is an interface having an AD converting function and a DA converting function. The AD converting function of the signal conditioner unit
11
converts signals from various sensors such as a torque sensor
8
. The DA converting function converts commands from the computer
10
, and output commands to various portion of the apparatus such as the dynamo controller
7
, the clutch actuator
4
and the throttle actuator
6
.
In a conventional engine testing apparatus, as shown in
FIGS. 5 and 9
, the moment of inertia of the engine is used to compute the load of rotating objects of an actual vehicle, i.e., an engine, a transmission, a differential gear and tire. This is because the moment of inertia of the engine is greater than moments of other rotating objects.
FIGS. 5 and 9
respectively show a conventional control flow and computation flow for the above-described engine testing apparatus. First, the control flow is described. In
FIG. 5
, reference numeral
13
represents a target pattern generator. The target pattern generator
13
, which is provided in the computer
10
, outputs a target speed signal V, to allow the engine
1
under test to run in a predetermined running pattern based on the target vehicle speed patterns
12
,
12
a
and
12
b
which have been inputted into the computer
10
. The target speed signal V, is inputted to a rotation control system
14
and a simulation vehicle control system
15
.
The rotation control system
14
and the simulation vehicle control system
15
are constituted in the following manner. First, the rotation control system
14
comprises a rotation generator
16
to which the target speed signal V, is inputted, a delay correcting circuit
17
, a butt portion
18
, a rotation feedback controller
19
and the dynamometer
2
. When the target speed signal V
r
is inputted to the rotation generator
16
, an engine target rotation number signal [a target value of the dynamometer rotation number (the rotation number, hereinafter)] R
r
is outputted from the rotation generator
16
based on the target speed signal V
r
.
For example, as shown in FIG.
4
(B), a target rotation number signal R
r
which is converted from the target vehicle speed pattern
12
a
shown in FIG.
4
(A) is obtained in simulation. That is, an engine rotation pattern
33
is obtained. Similarly, when the target vehicle pattern
12
b
, is employed, an engine rotation pattern
30
, which is converted from the target vehicle speed pattern
12
b
is obtained as shown in FIG.
6
. When the pattern is converted from target vehicle speed pattern
12
a
to the engine rotation pattern
33
or from the target vehicle speed pattern
12
b
to the engine rotation pattern
30
, a diameter of a tire, a final-drive ratio and a gear ratio in accordance the type of vehicle are taken into consideration.
Referring back to
FIG. 5
, the target rotation number signal R
r
becomes a control target rotation number signal R
ctl
through the delay correcting circuit
17
, and is outputted to the butt point
18
. Since an actual rotation number signal R
a
of the dynamometer
2
has been inputted to the butt point
18
, a deviation Re between the control target rotation number signal R
ctl
and an actual rotation number signal R
a
is PI-controlled, for example, by the rotation feedback controller
19
, thereby setting an operation amount signal Ud′. The operation amount signal Ud′ is sent to the dynamometer
2
.
In
FIG. 5
, the simulation vehicle control system
15
includes a torque generator
20
to which the target speed signal V
r
is inputted and further includes a butt point
21
to which the target speed V
r
is inputted and a speed feedback controller
22
are connected in parallel to a rear stage of the target pattern generator
13
which outputs the target speed signal V
r
. A torque control system
27
, which comprises an adding point
23
, a butt point
24
, a throttle map
25
, a throttle opening degree controller
26
and the engine
1
under test, is provided in the rear stage of the torque generator
20
and the speed feedback controller
22
. A simulation vehicle model
28
is provided in the rear stage of the torque control system
27
. The throttle map
25
is a map for determining a target throttle opening degree to control the engine. The simulation vehicle model
28
is a model for calculating a driving force of the vehicle using the engine output torque to convert the calculated value into a speed signal using the driving force.
In the simulation vehicle control system
15
, if the target speed V
r
is inputted to the torque generator
20
, a feedforward torque T
ff
, which is an output torque required for the engine from the torque generator
20
, is outputted to the adding point
23
. In this case, when the target vehicle speed pattern
12
or the target vehicle speed patterns
12
a
and
12
b
is converted into the feedforward torque T
ff
, a vehicle inertia weight and running resistance in accordance with the type of vehicle are taken into consideration.
The target speed signal V
r
is butted against an actual speed signal V
a
outputted from the simulation vehicle model
28
at the butt point
21
. A deviation there between is sent to the speed feedback controller
22
, and it is outputted to the adding point
23
as a feedback torque T
fb
. The feedforward torque T
ff
and the feedback torque T
fb
are added in the adding point
23
, and the target control torque signal T
ctl
is obtained. The target control torque signal T
ctl
is butted against an actual output torque valve T
a
of the engine
1
under test, a devi

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