On-vehicle electronic controller

Details On-vehicle electronic controller On-vehicle electronic controller

2001-11-14

2004-09-21

Dolinar, Andrew M. (Department: 3747)

Data processing: vehicles, navigation, and relative location

Vehicle control, guidance, operation, or indication

With indicator or control of power plant

C710S305000

Reexamination Certificate

active

06795767

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an on-vehicle electronic controller including a microprocessor used for controlling fuel supply of a vehicle engine, and particularly concerns an on-vehicle electronic controller which is improved in handling a number of input/output signals to miniaturize the controller and is improved to standardize the controller regarding the control on various kinds of vehicles.
2. Description of the Prior Art
FIG. 8
is a typical block circuit diagram showing a conventional one of such electronic controllers, in which an ECU (engine control unit)
1
composed of a single printed board includes a large LSI (integrated circuit component)
2
as a main component. In the LSI
2
, a CPU (microprocessor)
3
, a nonvolatile flash memory
4
, a RAM memory
5
, an input data selector
6
, an A/D converter
7
, an output latch memory
8
and so on are connected via a data bus
30
.
The ECU
1
operates in response to control power supplied from a power supply unit
9
, which is fed from an on-vehicle battery
10
via a power supply line
11
and a power supply switch
12
. An execution program, a control constant for controlling an engine, and soon are stored in the nonvolatile flash memory
4
in advance.
Meanwhile, a number of ON/OFF input signals from sensor switches
13
are supplied from bleeder resistors
14
, which serve as pull-up or pull-down resistors, to comparators
19
via series resistors
15
and parallel capacitors
16
that constitute noise filters. Input resistors
17
and reaction resistors
18
are connected to the comparators
19
. When a voltage across the parallel capacitor
16
exceeds a reference voltage applied to a negative terminal of the comparator
19
, a signal of logic “H” is supplied to the data selector
6
.
However, when a voltage across the parallel capacitor
16
decreases, the input from the reaction resistor
18
is added thereto. Thus, the output of the comparator
19
recovers to logic “L” since a voltage across the parallel capacitor
16
decreases to less than a reference voltage of the comparator
19
.
As described above, the comparator
19
acts as a level judging comparator having a hysteresis function. A number of outputs from the comparators
19
are stored in the RAM memory
5
via the data selector
6
and the data bus
30
.
Additionally, for example, the data selector
6
handles an input of 16 bits and outputs the input to the data bus
30
when receiving a chip select signal from the CPU
3
. Input points range over several tens points and a plurality of data selectors are used.
Further, a number of analog signals from the analog sensors
20
are supplied to the A/D converters
7
via the series resistors
21
and the parallel capacitors
22
that constitute noise filters. Digital outputs from the A/D converters, which receive chip select signals from the CPU
3
, are stored in the RAM memory
5
via the data bus
30
.
The control output of the CPU
3
is stored in the latch memory
8
via the data bus
30
and drives external loads
26
via output transistors
23
. A plurality of latch memories is used for a number of control output points, and the control output is stored in the latch memory chip-selected by the CPU
3
.
Additionally, reference numeral
24
denotes driving base resistors of the transistors
23
, reference numeral
25
denotes stable resistors, each connecting base/emitter terminals of the transistor
23
, and reference numeral
27
denotes a feeding power supply relay for the external load
26
.
A conventional device configured thus is disadvantageous as follows: the LSI
2
is large in size because the CPU
3
handles quite a large number of inputs and outputs, the parallel capacitors
16
and
22
acting as noise filters require capacitors having a variety of capacities in order to obtain a desired filter constant, causing difficulty in standardization, and a large capacitor is needed to obtain a large filter constant, increasing the ECU
1
in size.
As a measure for reducing the input/output terminals of the LSI
2
to miniaturize the LSI
2
, for example, Japanese Patent Laid-Open No. 7-13912 specification “INPUT/OUTPUT PROCESSING IC” discloses a method of time-sharing and transferring a number of input/output signals using a serial communication block.
However, this method requires noise filters with a variety of capacities and is not suitable for standardization of the device. Besides, a capacitor demands a large capacity to obtain a sufficient filter constant and is not suitable for miniaturization of the device.
Meanwhile, a concept has been known in which a digital filter is used as a noise filter for ON/OFF input signals and the filter constant is controlled by a microprocessor.
For instance, in “PROGRAMMABLE CONTROLLER” disclosed in Japanese Patent Laid-Open No. 5-119811 specification, when an input logic value of an external input signal subjected to sampling is successively set at the same value for more than one time, the signal is adopted and stored in an input image memory, and a filter constant changing command is provided for changing a sampling period.
In this method, although a filter constant can be changed freely, a microprocessor bears a large burden when handling a number of input signals, resulting in slower response of control. The response is the original object of the microprocessor.
Besides, as an example of a digital filter for ON/OFF signals, Japanese Patent Laid-Open No. 2000-89974 specification discloses “DATA STORAGE/CONTROL CIRCUIT”, in which a shift register is provided as hardware and sampling is carried out according to the above-mentioned concept.
Further, for example, Japanese Patent Laid-Open No. 9-83301 specification discloses “SWITCHED CAPACITOR FILTER”, in which a digital filter uses a switched capacitor as a noise filter for a multichannel analog input signal.
In this case as well, when handling a number of analog input signals, a microprocessor bears a large burden, resulting in slower response of control. The response of control is the original object of the microprocessor.
Besides, Japanese Patent Laid-Open No. 8-305681 specification discloses “MICROCOMPUTER”, in which a resistance of an analog filter composed of a resistor and a capacitor is switched on multiple stages to change a filter constant.
Incidentally, the above conventional device is disadvantageous as in the following.
Namely, as described above, the conventional device is partially but is not fully miniaturized and standardized in an integral manner.
Particularly in case of miniaturizing and standardizing an input/output circuit of a microprocessor, it is not possible to avoid reduction in original control capability and response of the microprocessor.
BRIEF SUMMARY OF THE INVENTION
In order to solve the above-mentioned problem, the first object of the present invention is to provide an on-vehicle electronic controller which reduces a burden of a microprocessor regarding processing input and output to improve its original control capability and response and which entirely miniaturizes and standardizes the controller by reducing an input filter in size.
Moreover, the second object of the present invention is to provide an on-vehicle electronic controller in which a control program and a control constant are changed for kinds of vehicles having different control specifications so as to readily standardize hardware in a more effective manner.
An on-vehicle electronic controller according to claim 1 is constituted by the microprocessor including the nonvolatile memory, in which a control program for a controlled vehicle, a control constant, and so on are written from the external tool, and the RAM memory for computing; the integrated circuit including the direct input interface circuits and the direct output interface circuits that are connected to the data bus of the microprocessor, the variable filter circuit having the indirect input interface circuits and the constant setting registers, and the communication control circuit; and the i

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