Internal-combustion engines – Engine speed regulator – Open loop condition responsive
Reexamination Certificate
2002-11-13
2004-10-19
Huynh, Hai (Department: 3747)
Internal-combustion engines
Engine speed regulator
Open loop condition responsive
C123S399000, C701S110000
Reexamination Certificate
active
06805094
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an on-vehicle engine control apparatus in which an intake amount of vehicle engine and so on are electronically controlled by an electric motor.
In particular, the invention relates to an on-vehicle engine control apparatus for carrying out electronic control of an intake amount and so on employing a system in which a CPU (microprocessor) is used to carry out main control of ignition/fuel supply of engine and so on as a whole, and by which safety in controlling the whole engine is improved.
2. Description of the Related Art
Electronic throttle control has been widely put into practical use so that intake throttle valve opening of an engine is controlled by an electric motor according to degree of working an accelerator pedal. It is a recent trend to employ a wireless type control without accelerator wire. But there is another type of control that uses an accelerator acting as backup means in combination with a motor, or a further type in which an accelerator wire is used in normal driving and an electric motor is used in constant-speed driving.
On the other hand, the entire engine control includes main control for an engine drive unit such as ignition coil (in case of gasoline engine) or fuel injection valve and auxiliary control for peripheral machine such as a transmission solenoid valve or an air conditioner driving electromagnetic clutch. Various types of CPU have been heretofore proposed in the aspect of combining the engine control with the mentioned throttle control.
FIG. 10
shows a constitution of a CPU for use in an on-vehicle engine control apparatus according to a first type of prior art and, in this type, one single CPU
1
a
carries out the entire control.
Connected to this CPU
1
a
are a sensor for detecting an engine speed, a crank angle sensor, an airflow sensor for measuring an intake amount, an intake pressure sensor, an exhaust gas sensor, a coolant temperature sensor, an accelerator position sensor (hereinafter referred to as APS) for measuring a degree of working the accelerator pedal, a throttle position sensor (hereinafter referred to as TPS) for measuring a throttle valve opening, a shift position sensor for detecting a transmission lever position, and a large number of on-off or analog input signals
11
a.
Control outputs of the CPU
1
a
includes main machinery/auxiliary machinery control outputs
21
a
such as an ignition coil, a fuel injection solenoid valve, a transmission solenoid valve, an exhaust gas circulation control solenoid valve, etc., and a throttle control motor
22
a.
The Japanese Patent Publication (unexamined) No. 176141/1990 titled “Control Apparatus for Internal Combustion Engine” and the Japanese Patent Publication (unexamined) No. 141389/1999 titled “Throttle Control Apparatus of Internal Combustion Engine” disclose this first type of prior art as described above in which the entire control is carried out by one single CPU.
A problem exists in such a type of carrying out the entire control using one CPU. For example, such a type of control system is insufficient in safety at the time of occurrence of any error or abnormality in the system, and performance and specification are not sufficiently secured because of a heavy burden on the CPU.
Particularly since it is possible to prevent the engine from running out of control by accurately suppressing an intake amount, control of the intake amount is the most important requirement in terms of safety. Therefore it is a market trend to employ required sensors and CPU in the form of dual system for the electronic throttle control.
FIG. 11
shows a constitution of a CPU for use in an on-vehicle engine control apparatus according to a second type of prior art. In this second type, main machinery and auxiliary machinery
21
b
are controlled by a first CPU (CPU
1
)
1
b
, and main machinery/auxiliary machinery control input signals
11
b
is connected to the required CPU.
A second CPU (CPU
2
)
2
b
receives a throttle control input signal
12
b
of the APS, the TPS, etc. and controls a throttle control motor
22
b
. A third CPU (CPU
3
)
3
b
receives a monitor control input signal
13
b
and generates a monitor control output
23
b
, thereby safety of the electronic throttle control is improved.
The Japanese Patent Publication (unexamined) No. 278502/1994 titled “Cruise Control Apparatus” and the Japanese Patent Publication (unexamined) No. 2152/1999 titled “Constant-Speed Driving Apparatus for Vehicle” do not mention the foregoing first CPU (CPU
1
)
1
b
. But those patent literatures gives a description defined to a throttle control in which the second CPU (CPU
2
)
2
b
acts as a main CPU and the third CPU (CPU
3
)
3
b
acts as a sub-CPU.
In this concept, a constant-speed control apparatus is added to the conventional accelerator-wire-type engine control apparatus, and consequently, the constitution with the three CPUs is complicated and expensive.
FIG. 12
shows a constitution of a CPU for use on-vehicle engine control apparatus according to a third type of prior art. In this third type, main machinery and auxiliary machinery
21
c
are controlled by a first CPU (CPU
1
)
1
c
. A related main machinery/auxiliary machinery control input signal
11
c
is connected to the CPU
1
c.
A second CPU (CPU
1
)
2
c
receives a throttle control input signal and a monitor control input signal
12
c
of the APS, the TPS, and so on, and generates a control output and a monitor control output
22
c
to the throttle control motor. The first CPU (CPU
1
)
1
c
and the second CPU (CPU
2
)
2
c
monitor each other.
In the CPU constitution of this type, the first CPU (CPU
1
)
1
c
acts as a so-called ECU (engine control unit) and the second CPU (CPU
2
)
2
c
acts as a so-called a TCU (a throttle control unit). In this manner, this constitution intends to improve safety of the entire system through mutual monitoring.
“Engine Control Apparatus” disclosed in the Japanese Patent Publication (unexamined) No. 270488/1996 is of a two-CPU constitution in which an accelerator wire is jointly used, and “Throttle Valve Control Apparatus” disclosed in the Japanese Patent Publication (unexamined) No. 97087/2000 is of a wireless two-CPU constitution.
Both of them disclose fail-safe control means that enables smooth limp/home driving in case of occurrence of any abnormality.
On the other hand, in the Japanese Patent Publication (unexamined) No. 249015/1994 titled “Control Apparatus for Vehicle”, the control apparatus is provided with a bypass valve for limp driving. A motor controls opening of the main throttle valve to be fully closed and returned by a return spring. This prior art discloses limp driving means acting in case of an excess-open abnormality when it is impossible to fully close and return the main throttle valve due to an abnormality in the motor, an actuator, or the like.
In the prior arts described above, an idle cylinder level is set conforming to an output voltage of the throttle position sensor (TPS) that detects a main throttle valve opening and to an output voltage of the accelerator position sensor (APS) that detects a degree of acting the accelerator pedal. Fuel supply to a part of a multi-cylinder engine is stopped, and number of effective cylinders is reduced in order to suppress the engine speed.
In the prior arts as described above, there still remain several problems in using only one single CPU. For example, safety is not assured and a burden on the CPU control is excessively heavy, and it is therefore essential to reduce the burden on the CPU and improve safety monitoring.
However, the engine drive control such as ignition control or fuel injection control is closely related to the throttle control, and it will not be a good idea to carry out separately the engine drive control and the throttle control with separate CPUs.
SUMMARY OF THE INVENTION
Accordingly, a first object of the present invention is to provide an on-vehicle engine control apparatus suitable for carrying out an engin
Hashimoto Kohji
Nakamoto Katsuya
Huynh Hai
Mitsubishi Denki & Kabushiki Kaisha
LandOfFree
On-vehicle engine control apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with On-vehicle engine control apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and On-vehicle engine control apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3300207