Fuel additive delivery system

• US 6,068,672 A
• Filed: 08/27/1998
• Issued: 05/30/2000
• Est. Priority Date: 02/18/1997
• Status: Expired due to Term

• Current Assignee: TI Group Automotive Systems LLC
• Original Assignee: Walbro Corporation (Sun Capital Partners Incorporated)
• Inventors: Egle, Lawrence E., Watson, Charles J.
• Primary Examiner(s): Howard, Jacqueline V.
• Application Number:
  US09/141,487
• Time in Patent Office: 642 Days
• Field of Search: 44/903, 44/629, 44/639, 123/1 A
• US Class Current: 44/629
• CPC Class Codes: B60K 15/00 Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks tanks in general B65D, F17C; supplying combustion engines with combustible mixtures or constituents F02M
• CPC Class Codes: B60K 2015/03348 for supplying additives to fuel
• CPC Class Codes: F02B 51/00 Other methods of operating engines involving pretreating of, or adding substances to, combustion air, fuel, or fuel-air mixture of the engines
• CPC Class Codes: F02D 19/12 peculiar to engines working with non-fuel substances or with anti-knock agents, e.g. with anti-knock fuel
• CPC Class Codes: F02M 25/00 Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture adding secondary air to fuel-air mixture F02M23/00; adding exhaust gases F02M26/00; fuel-injection apparatus operating simultaneously on two or more fuels or on a liquid fuel and another liquid F02M43/00
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y10S 44/903 Method including measuring, testing or automatic control

Abstract

A fuel dosing system to provide a controlled level of cereum additive from an additive tank either within or external to a diesel powered vehicle'"'"'s fuel storage tank. The present invention maintains a concentration of cerium that is optimized to assure proper regeneration of a particulate trap used to control particulate emissions from the vehicle'"'"'s exhaust. The present invention determines the additive dosage required by monitoring the fuel added to the tank during refueling of the vehicle and responds with a proper dose of an optimized amount of additive. The present invention is self contained and imposes a minimum encroachment on the vehicle fuel and electrical system and may also provide appropriate alarm signals to warn of additive depletion and other possible malfunctions.

Claims

1. An apparatus for mixing a fuel additive to a fuel comprising:

a fuel tank for a vehicle;

a level sensor mounted in said fuel tank for providing an electric signal indicative of the level of fuel in said fuel tank;

an additive system for holding a supply of fuel additive;

electric pump for dispensing a predetermined precise amount of said additive to fuel in said fuel tank in response to activation of the pump;

an electronic control circuit having a microprocessor with a clock and a memory, the control circuit utilizing the electric signal of the level sensor to determine fuel levels, determining a first fuel level and storing the first fuel level in memory, determining at least one succeeding second fuel level lesser than the first fuel level and storing in memory such lesser second fuel level, subsequently determining a third fuel level significantly greater than the lesser second fuel level stored in memory, using the third fuel level and the last lesser second fuel level stored in memory to determine the amount of additive to be delivered to the fuel in the fuel tank in proportion to the quantity of fuel added to the fuel tank, and producing control signals causing the electric pump to be energized to deliver to the fuel in the tank the determined quantity of fuel additive which is proportional to the quantity of fuel added to the tank, and

an interrupt circuit for preventing the sending of said control signals if the difference between said second level and said third level is in excess of a predetermined value indicating the electric signal of said third level is invalid.

2. The apparatus according to claim 1 wherein said interrupt circuit further comprises:

an attitude sensing switch for preventing the sending of said control signals if said fuel tank is;

(i) not level or (ii) under acceleration.

3. The apparatus according to claim 1 wherein said interrupt circuit further comprises:

a battery level detection circuit configured to prevent the sending of said control signals when a battery voltage is outside a predetermined operating range.

4. The apparatus according to claim 1 wherein said control circuit further comprises:

a lookup table for determining said fixed amount of additive in response to the difference between said second and third levels.

5. The apparatus according to claim 4 wherein said electric pump comprises

a positive displacement pump for adding a fixed amount of additive to fuel in said fuel tank for each pump stroke of said pump, and wherein a number of pump strokes is determined by said look-up table.

6. The apparatus according to claim 1 further comprising:

a heat exchanger connected between said pump and said fuel tank to stabilize fluid viscosity at low temperatures of the additive.

7. The apparatus according to claim 5 wherein said control circuit further comprises:

a memory for storing a maximum number of pump strokes prior to exhausting said supply of fuel additive;

an error circuit configured to provide an error signal when said maximum number of pump strokes has occurred; and

a counter circuit for decrementing the number of pump strokes in said memory.

8. The apparatus according to claim 7 wherein said memory stores the number of pump strokes as they occur for use in the event of an interruption of the operation of said apparatus.

9. The apparatus set forth in claim 1 further comprising means coupled to said pump for sensing operation of said pump and thereby confirming addition of said predetermined amount of additive to said fuel tank.

10. The apparatus set forth in claim 9 wherein said operation-sensing means comprises pressure switch means coupled to an output of said pump.

11. The apparatus set forth in claim 5 comprising operation-sensing means detecting each stroke of said pump and thereby determining the amount of additive added to fuel in said fuel tank by said pump.

12. The apparatus according to claim 1 wherein said fuel comprises diesel fuel and said additive comprises cerium.

13. The apparatus according to claim 1 wherein said electric pump comprises a positive displacement pump for adding a fixed amount of additive to fuel in said fuel tank for each pump stroke of said pump, and further comprising a register storing the number of pump strokes determined to be needed to deliver to the fuel tank a quantity of additive, and decrementing the register in response to the actual number of strokes of the electric pump when energized by the control circuit to deliver additive to the fuel tank.

14. The apparatus according to claim 1 wherein the control circuit further comprises a battery providing a voltage to the level sensor, and wherein the control circuit comprises an analog-to-digital converter receiving an electric signal from the level sensor, the actual battery voltage is a reference to the analog-to-digital converter, and the actual battery voltage is compared to the electric signal of the level sensor to improve the resolution of the level sensor.

15. A method of mixing a fuel additive to fuel in a fuel tank of a vehicle comprising the steps of:

providing a level sensor using an electric signal indicative of the level of fuel in the fuel tank;

providing an additive tank for holding a supply of fuel additive;

providing an electric pump connected with the additive tank for providing a predetermined precise amount of additive to fuel in the fuel tank in response to each delivery stroke of the pump;

providing an electronic control circuit having a microprocessor with a clock and a memory, the control circuit utilizing the electric signal of the level sensor to determine fuel levels, determining a first fuel level and storing the first fuel level in memory, determining at least one succeeding second fuel level lesser than the first fuel level and storing in memory such lesser second fuel level, subsequently determining a third fuel level significantly greater than the lesser second fuel level stored in memory, utilizing the third fuel level and the lesser second fuel level stored in memory to determine the number of pump strokes needed to deliver an amount of additive to fuel in the fuel tank in proportion to the quantity of fuel added to the fuel tank, and producing control signals causing the electric pump to be energized for the determined number of strokes of the electric pump to deliver the quantity of additive to fuel in the fuel tank,

storing a determined maximum number of pump strokes in a register; and

decrementing said register in response to said number of strokes.

17. The method according to claim 15 further comprising the steps of:

determining if said fuel tank is in a level position while determining said second level;

redetermining said second level if said fuel tank is not in said level position;

determining if said fuel tank is in a level position while determining said third level; and

redetermining said third level if said fuel tank is not in said level position.

18. The method set forth in claim 15 comprising the additional step of monitoring operation of the pump to confirm the amount of additive added to the tank.

19. The method set forth in claim 18 wherein said pump comprises a fixed displacement pump, and wherein the amount of additive is controlled by controlling the number of strokes of the pump.

16. A method of mixing a fuel additive to fuel in a fuel tank of a vehicle comprising the steps of:

providing a level sensor using an electric signal indicative of the level of fuel in the fuel tank;

providing an additive tank for holding a supply of fuel additive;

providing an electric pump connected with the additive tank for providing a predetermined precise amount of additive to fuel in the fuel tank in response to each delivery stroke of the pump;

providing an electronic control circuit having a microprocessor with a clock and a memory, the control circuit utilizing the electric signal of the level sensor to determine fuel levels, determining a first fuel level and storing the first fuel level in memory, determining at least one succeeding second fuel level lesser than the first fuel level and storing in memory such lesser second fuel level, subsequently determining a third fuel level significantly greater than the lesser second fuel level stored in memory, utilizing the third fuel level and the lesser second fuel level as stored in memory to determine the number of pump strokes needed to deliver an amount of additive to fuel in the fuel tank in proportion to the quantity of fuel added to the fuel tank, and producing control signals causing the electric pump to be energized for the determined number of strokes of the electric pump to deliver the quantity of additive to fuel in the fuel tank, and

resampling said third level of fuel if the difference between said second level and said third level is in excess of a predetermined value indicating said third level is invalid.