Claims
- 1. An ignition advance correction device for a motor vehicle internal combustion engine, comprising an ignition distributor which has at least one contact breaker arm, a fixed support, an advance lever pivotally mounted on the fixed support and itself pivotally carrying said contact breaker arm, and first and second depression responsive devices connected to the advance lever and adapted to sense variations in pressure at different locations in the engine, a blocking means which includes a connecting means coupling said advance lever to said first depression responsive device and a control element coupling said advance lever to said second depression responsive device, said advance lever being moved in response to variations in pressure sensed by each of said devices, and a blocking element connected to said fixed support and releasably coupled to said first depression responsive device, said blocking element being spaced a predetermined distance from said control element and adapted to contact said control element when said second depression responsive device has moved said predetermined distance, said blocking element being coupled to said first device to be released from said first device by action of said first device after said second device has moved said predetermined distance, whereby said advance lever is moved by each of said devices via said connecting means and said control element independently of the other device so that each device is able to provide a predetermined ignition advance in response to the depression prevailing at a respective one of said locations independently of a depression prevailing at the other device, said blocking element being coupled to said first device and said predetermined distance being selected such that, when not activated by depression, said first device acts via said blocking element to limit the amount of ignition advance which can be effected by said second device acting alone, but permits further ignition advance beyond said predetermined ignition advance by said second device during depression activation of said first device which releases said blocking element from said first device so that said second device acts on said advance lever independently of said first device during said further ignition advance.
- 2. A device according to claim 1, wherein the advance lever is connected via said connecting means and said control element respectively to movable mechanisms of the pair of depression responsive devices by means of two drive pins engaged in two longitudinal slots formed towards the free ends of connecting rods of the respective mechanisms, the arrangement being such that, in the rest position of the device each pin is against the base of its associated one of the slots and is able to move therein longitudinally along a length corresponding to the angular movement of the advance lever under the action of the depression responsive device in the rod of which the other slot is formed.
- 3. A device according to claim 2, wherein said blocking element includes a blocking lever which articulates about a shaft rigid with the fixed support and which is able to limit the travel of the movable mechanism of said second depression responsive device when said first pressure responsive device is not subject to sufficient depression.
- 4. A device according to claim 3, wherein the blocking lever has at one of its ends a pin which engages in a slot formed in the rod of the movable mechanism of said first pressure responsive device, the slot being arranged so as, on the one hand, to lock the blocking lever when said first pressure responsive device is not subject to sufficient depression and as a result to form an abutment against the movement of the pin of the advance lever acted upon by said second pressure responsive device, and on the other hand, to unlock the blocking lever when said first pressure responsive device is subject to sufficient depression and as a result to allow the complete movement of the rod of said second pressure responsive device.
- 5. A device according to claim 2, wherein an extension of the rod of the movable mechanism connected to said second pressure responsive device is connected to the rod of the movable mechanism connected to said first pressure responsive device in such a way that it limits the travel of the movable mechanism of said second pressure responsive device when said first pressure responsive device is not subject to sufficient depression.
- 6. A device according to claim 5, wherein the extension of the rod of said second pressure responsive device has a pin adapted to move in a slot formed in the other rod.
- 7. A device according to claim 5 or 6, wherein the extension of the rod of said second pressure responsive device is joined on to said second device rod.
- 8. A device according to claim 7, wherein the rod extension has means for adjusting its useful length.
- 9. A device according to claim 8, wherein the adjustment means is constituted by a screw which passes through a slot formed in the rod extension to screw into a threaded hole in the rod having the extension and by a fork which holds captive a pin of the contact breaker carrying arm which moves in the said rod.
Priority Claims (1)
Number |
Date |
Country |
Kind |
77 31546 |
Oct 1977 |
FRX |
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Parent Case Info
This is a continuation, of application Ser. No. 951,627, filed Oct. 16, 1978 now abandoned.
US Referenced Citations (11)
Foreign Referenced Citations (3)
Number |
Date |
Country |
2244456 |
Apr 1973 |
DEX |
2459107 |
Jun 1975 |
DEX |
2402083 |
Apr 1979 |
FRX |
Continuations (1)
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Number |
Date |
Country |
Parent |
951627 |
Oct 1978 |
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