Fixed throttle torque demand strategy
First Claim
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1. A method for operating an internal combustion engine having a fixed throttle including the steps of:
- determining a desired driver engine torque;
determining a maximum available engine torque;
controlling engine torque as a function of the ratio of a desired engine torque to a maximum available engine torque;
sensing engine speed, throttle angle, exhaust gas recirculation, intake air temperature, and accelerator pedal position;
developing signals representing engine speed, throttle angle, exhaust gas recirculation, intake air temperature, and accelerator pedal position;
calculating the maximum available engine load;
calculating the maximum available engine torque using engine load and engine speed;
determining desired driver demand engine torque as a percentage of the maximum torque available; and
reducing actual engine torque to desired engine torque by retarding spark advance and cutting out fuel injector operation.
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Abstract
This invention teaches operating a vehicle with a fixed throttle by determining a modified torque which is determined as a function of driver demand torque. Such modified torque is used to determine the amount spark retard or fuel cut-out required to achieve the demanded torque.
65 Citations
4 Claims
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1. A method for operating an internal combustion engine having a fixed throttle including the steps of:
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determining a desired driver engine torque; determining a maximum available engine torque; controlling engine torque as a function of the ratio of a desired engine torque to a maximum available engine torque; sensing engine speed, throttle angle, exhaust gas recirculation, intake air temperature, and accelerator pedal position; developing signals representing engine speed, throttle angle, exhaust gas recirculation, intake air temperature, and accelerator pedal position; calculating the maximum available engine load; calculating the maximum available engine torque using engine load and engine speed; determining desired driver demand engine torque as a percentage of the maximum torque available; and reducing actual engine torque to desired engine torque by retarding spark advance and cutting out fuel injector operation. - View Dependent Claims (2, 3)
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4. A method for operating an internal combustion engine including the steps of:
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determining the throttle is in a fixed position; sensing the following inputs;
space="preserve" listing-type="tabular">______________________________________ ACT air charge temperature BP barometric pressure N engine speed ETP.sub.-- rel tp.sub.-- rel of electronic throttle EGRACT actual egr rate IAC intake runner control state TQ.sub.-- LOSS tp losses for inferred tq % FA percent foot angle;
______________________________________determining the following calibration parameters;
space="preserve" listing-type="tabular">______________________________________ FN059 temperature compensation for inferred bp FN1036A load at sea level for n vs tp.sub.-- rel FN1036B load at sea level for n vs tp.sub.-- rel, secondarys open FN1037 load from egr, n vs tp.sub.-- rel FN1615A indicated engine torque, n vs load FN0ETC.sub.-- FMEM driver dem and transfer function, percentage of torque available; and
______________________________________generating the following outputs in accordance with the following equations;
space="preserve" listing-type="tabular">______________________________________ max.sub.-- av.sub.-- load maximum load available for a fixed ECT position max.sub.-- av.sub.-- tq maximum tq available for a fixed ETC position da.sub.-- tq.sub.-- fmem driver requested engine torque for FMEM situation ______________________________________if the state of IAC equals "1", then determining;
space="preserve" listing-type="tabular">______________________________________ max.sub.-- av.sub.-- load = [fn1036b(n,etp.sub.-- rel) - egract/10 * fn1037(n,etp.sub.-- rel)] * fn059(act)*bp/29.92 ______________________________________if the state of IAC does not equal "1", then determining;
space="preserve" listing-type="tabular">______________________________________ max.sub.-- av.sub.-- load = [fn1036a(n,etp.sub.-- rel) - egract/10 * fn1037(n,etp.sub.-- rel)] * fn059(act)*bp/29.92 ______________________________________calculating maximum available torque using;
space="preserve" listing-type="equation">max.sub.-- av.sub.-- tq=fn1615a(n,max.sub.-- av.sub.-- laod)calculating desired torque using;
space="preserve" listing-type="tabular">______________________________________ da.sub.-- tq.sub.-- fmem = [max.sub.-- av.sub.-- tq - tq.sub.-- loss]*fn0etc.sub.-- fmem(% fa) ______________________________________thereby calculating desired torque by determining a net torque by subtracting an engine torque loss from maximum available torque at the fixed throttle condition, such net torque being then multiplied by a calibration function indicating a desired torque percentage, so that the percentage of desired torque with respect to maximum torque is determined as a function of the percentage of a foot angle indicating accelerator position; and sending da-- tq-- fmem to a torque control module, where a number of cylinders to be turned off is determined and spark advance reduction is calculated and implemented.
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Specification