1. A control process for controlling the combustion of an internal combustion engine with controlled ignition and liquid fuel direct injection, in which the engine comprises at least one cylinder with a combustion chamber, at least one intake means, at least one exhaust means and at least one direct injection means for liquid fuel in order to obtain a fuelair mixture in the combustion chamber, the control process comprising:
determining at least one operational zone of the engine in which particulates are emitted during combustion of the fuelair mixture; and
for operation of the engine in this determined zone, introducing into the combustion chamber another fuelair mixture resulting from indirect injection of a gaseous fuel comprising natural vehicle gas (NVG) or liquid petroleum gas (LPG).
2. The control process according to claim 1, wherein the fuelair mixture is obtained from a liquid gasoline fuel.
3. The control process according to claim 2, wherein the gaseous fuel comprises natural vehicle gas (NVG).
4. The control process according to claim 2, wherein the gaseous fuel comprises liquid petroleum gas (LPG).
5. The control process according to claim 1, wherein the gaseous fuel comprises natural vehicle gas (NVG).
6. The control process according to claim 1, wherein the gaseous fuel comprises liquid petroleum gas (LPG).
7. The control process according to claim 1, wherein determining the at least one operational zone comprises determining at least one operational zone from tests and storing the parameters for the at least one operational zone in an engine control unit.
8. The control process according to claim 1, wherein determining the at least one operational zone comprises determining at least one operational zone from a measurement carried out by a particulate sensor.
9. The control process according to claim 8, wherein the particulate sensor is provided in an exhaust line of the engine.
10. The control process according to claim 8, wherein the particulate sensor is provided in an exhaust manifold connected to the exhaust means.
11. A control process for controlling the combustion of an internal combustion engine with controlled ignition and liquid fuel direct injection, in which the engine comprises at least one cylinder with a combustion chamber, at least one intake comprising intake pipework and an intake valve, at least one exhaust and at least one direct injector for liquid fuel in order to obtain a first fuelair mixture in the combustion chamber, the control process comprising:
determining if the engine is operated in an operational zone of the engine in which particulates are emitted during combustion of the first fuelair mixture; and
if the engine is being operated in an operational zone of the engine in which particulates would be emitted by combustion of the fuelair mixture, indirectly injecting into the combustion chamber a gaseous fuel comprising natural vehicle gas (NVG) or liquid petroleum gas (LPG).
12. The control process according to claim 11, wherein the gaseous fuel comprises natural vehicle gas (NVG).
13. The control process according to claim 11, wherein the gaseous fuel comprises liquid petroleum gas (LPG).
14. The control process according to claim 11, wherein determining if the engine is operated in an operational zone of the engine in which particulates are emitted during combustion of the first fuelair mixture comprises determining if the engine is being operated within parameters stored in an engine control unit, the parameters being determined from tests.
15. The control process according to claim 11, wherein determining the at least one operational zone comprises determining at least one operational zone from a measurement carried out by a particulate sensor.
16. The control process according to claim 15, wherein the particulate sensor is provided in an exhaust line of the engine.
17. The control process according to claim 15, wherein the particulate sensor is provided in an exhaust manifold of the engine.
18. The control process according to claim 11, wherein the engine further comprises an engine control unit and a gaseous fuel injector configured to inject gaseous fuel into the intake pipework so as to obtain a second fuelair mixture that is then introduced into the combustion chamber when the intake valve opens, and wherein, if the engine is being operated in an operational zone of the engine in which particulates would be emitted by combustion of the fuelair mixture, the engine control unit controls the at least one direct injector for liquid fuel to reduce a quantity of liquid fuel introduced into the combustion chamber and controls the gaseous fuel injector to inject the gaseous fuel into the intake pipework so as to obtain the second fuelair mixture that is then introduced into the combustion chamber when the intake valve opens.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A clock generator comprising:
a current controlled oscillator (ICO) having an input for receiving a control current, and an output for outputting clock signals of a frequency according to the control current; and
a biasing circuit electrically connected to the ICO comprising:
a controlled current generator having a first current output coupled to the input of the ICO for outputting the control current, and a second current output copying the first current output with a predetermined ratio;
a resistor having one end coupled to the second current output of the controlled current generator;
an operational amplifier (opamp) having a first input coupled to the second current output of the controlled current generator, a second input, and an output coupled to the controlled current generator;
a diode having an end coupled to the second input of the opamp; and
a current source having a first end coupled to the end of the diode and a second end coupled to the output of the opamp,
wherein substantially all of the current from the current source flows through the diode and substantially all of the current from second current output flows through the resistor.
2. The clock generator of claim 1 further comprising an inverter coupled to the output of the ICO.
3. The clock generator of claim 1 further comprising a buffer coupled to the output of the ICO.
4. The clock generator of claim 1 wherein the controlled current generator comprises:
a first PMOS comprising:
a source coupled to a voltage source;
a drain coupled to the input of the ICO; and
a gate coupled to the output of the opamp; and
a second PMOS comprising
a source coupled to the voltage source;
a drain coupled to the first input of the opamp; and
a gate coupled to the output of the opamp.
5. The clock generator of claim 1 wherein the current source is a PMOS, the first end of the current source being a drain of the PMOS, the second end of the current source being a gate of the PMOS.
6. The clock generator of claim 1 wherein the ICO is a ring oscillator.
7. The clock generator of claim 1 wherein the diode is a parasitic bipolar.
8. The clock generator of claim 1 wherein the first current output of the controlled current generator is substantially equal to the second current output of the controlled current generator with reduced low-frequency jitter.
9. A biasing circuit for controlling a current oscillator, the biasing circuit comprising:
a controlled current generator having a first current output for outputting a control current, and a second current output copying the first current output with a predetermined ratio;
a resistor having a first end coupled to the second current output of the controlled current generator, and a second end coupled to a first voltage;
an operational amplifier (opamp) having a first input coupled to the second current output of the controlled current generator, a second input, and an output electrically coupled to the controlled current generator;
a diode having a first end coupled to the second input of the opamp, and a second end coupled to said first voltage; and
a current source having a first end coupled to the end of the diode, a second end coupled to the output of the opamp, and a third end coupled to a second voltage,
wherein substantially all of the current from the current source flows through the diode and substantially all of the current from second current output flows through the resistor.
10. The biasing circuit of claim 9 wherein the controlled current generator comprises:
a first PMOS comprising:
a source coupled to said second voltage;
a drain for outputting the control current; and
a gate coupled to the output of the opamp; and
a second PMOS comprising
a source coupled to said second voltage;
a drain coupled to the first input of the opamp; and
a gate coupled to the output of the opamp.
11. The biasing circuit of claim 9 wherein the current source is a PMOS, the first end of the current source being a drain of the PMOS, the second end of the current source being a gate of the PMOS, the third end of the current source being a source of the PMOS.
12. The biasing circuit of claim 9 wherein the diode is a parasitic bipolar.
13. The biasing circuit of claim 9 wherein said second voltage is higher than said first voltage.
14. The biasing circuit of claim 9 wherein said first voltage is ground.