Engine control unit

1. An engine control unit for controlling an automobile engine, which is equipped with a booster circuit for boosting the voltage of battery power source, an injector driving circuit for driving an injector by making use of a boosted high voltage, and a microcomputer for controlling the engine;

wherein the engine control unit is featured in that:

an LC module mounted with a booster coil constituting the booster circuit and with an electrolytic capacitor, a power module mounted with a rectifying device constituting the booster circuit and the injector driving circuit and with a switching device, and a control circuit board mounted with the microcomputer and with a connector acting as an interface for an external member of the engine control unit are laminated each other;

the power module is partitioned into at least two portions and fixedly contacted, through a heat radiation part, with a housing cover; and

heat radiation fins are arranged on an outer surface of the housing cover where the power module is disposed.

2. The engine control unit according to claim 1 , wherein the LC module is equipped with a resinous case having built-in bus bar wirings; the booster coil and the electrolytic capacitor, both electrically connected with the bus bar wirings, are mounted on the resinous case; external terminals which are formed integral with the bus bar wirings are configured to pass through the control circuit board thereby enabling the external terminals to electrically connect with the control circuit board; and surfaces of the booster coil and the electrolytic capacitor are respectively fixedly contacted, via the heat radiation part, with the housing cover.

3. The engine control unit according to claim 1 , wherein the LC module 6 is disposed at a central portion of the housing cover and at least one of the power module is disposed on one side of the LC module and the rest of the power module is disposed on the opposite side of the LC module.

4. The engine control unit according to claim 1 , wherein the power module comprises a heat radiation layer having a first main face and a second main face located opposite to the first main face; an insulating layer disposed on the first main face of heat radiation layer; a wiring circuit portion formed on the insulating layer; electronic components, including the rectifying device and switching device, which are electrically connected with the wiring circuit portion which is formed on the insulating layer; and a plurality of external terminals which are arranged in a row along the longitudinal sidewall of the power module and electrically connected with the wiring circuit portion; wherein the external terminals are configured to pass through the control circuit board thereby enabling the external terminals to electrically connect with the control circuit board.

5. The engine control unit according to claim 4 , wherein the heat radiation layer is formed of a metallic material of high-heat conductance such as an aluminum alloying material or a copper alloying material.

6. The engine control unit according to claim 4 , wherein the insulating layer is formed of an insulating resinous material of high-heat conductance.

7. The engine control unit according to claim 4 , wherein the wiring circuit portion is formed of wirings made of a copper alloying material and having a thickness of not less than 100 μm.

8. The engine control unit according to claim 4 , wherein the external terminals are respectively provided with a stepped portion at a connecting portion between the external terminals and the wiring circuit portion.

9. The engine control unit according to claim 4 , wherein the injector comprises a first terminal for passing electric current for actuating the injector and a second terminal for transmitting controlling signals, wherein the first terminal has a width larger than that of the second terminal.