Engine start control apparatus

Abstract

Oil level detection sensor detects an oil level in a crankcase. First charging circuit includes a serial connection of a first charging capacitor for charging a reverse voltage produced in a primary coil, the detection sensor, and a first diode. Thyristor is turned on, in response to voltage-charging of the first charging capacitor, to disable an ignition operation of an ignition circuit. Second charging circuit includes a serial connection of a second charging capacitor for charging a forward voltage, produced in the primary coil, and a second diode. Transistor is turned on, in response to voltage-charging of the second charging capacitor, to disable a turning-on operation of the thyristor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Certain preferred embodiments of the present invention will hereinafter be described in detail, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a block diagram schematically showing an engine and an engine start control apparatus according to an embodiment of the present invention;

FIGS. 2A and 2B are views explanatory of a construction and behavior of relevant sections of a float-type oil level detection sensor in the engine start control apparatus of FIG. 1; and

FIG. 3 is a circuit diagram of the engine start control apparatus.

Claims

1. An engine start control apparatus comprising: a float-type oil level detection sensor for generating an oil-level-lowering detection signal by detecting when a level of oil stored in a crankcase of an engine has lowered to a preset lower limit level;an ignition circuit for performing an ignition operation by controlling an ignition coil, connected to an ignition plug, to cause the ignition plug to produce a spark discharge; anda control section for controlling said ignition circuit in accordance with a detection signal output by said float-type oil level sensor, said control section including: a first charging circuit comprising a serial connection of: a first charging capacitor for charging a reverse voltage produced in a primary coil of the ignition coil; said float-type oil level detection sensor; and a first diode;a first switching element that is turned on, in response to voltage-charging of said first charging capacitor, to disable the ignition operation of said ignition circuit;a second charging circuit comprising a serial connection of: a second charging capacitor for charging a forward voltage produced in the primary coil of the ignition coil; and a second diode; anda second switching element that is turned on, in response to voltage-charging of said second charging capacitor, to disable an turning-on operation of said first switching element.

2. The engine start control apparatus of claim 1, wherein said first switching element is connected in parallel to said ignition circuit.

3. The engine start control apparatus of claim 1, wherein said ignition circuit includes a transistor circuit connected in parallel to the primary coil, and a thyristor connected to a base of the transistor circuit, and said first switching element is connected in parallel to the thyristor.

4. The engine start control apparatus of claim 1, wherein said second switching element comprises a transistor connected to a gate-cathode path of said first switching element.