Engine start control system for a hybrid vehicle

1. A vehicle comprising:

a powertrain including an engine and an electric machine;

an engine disconnect clutch configured to connect and disconnect the engine to and from the powertrain, respectively;

a drive horizon system configured to generate a powertrain power output profile required to propel the vehicle over a predetermined route based on navigation data, the navigation data including a road grade of the predetermined route, a speed limit of the predetermined route, a road curvature of the predetermined route, traffic conditions of the predetermined route, or weather conditions of the predetermined route; and

a controller programed to,

in response to the electric machine operating to propel the vehicle over the predetermined route while the engine is shutdown and an upcoming increase in the powertrain power output profile to a value that is greater than a threshold, initiate an engine start at a predetermined time period before the upcoming increase in the powertrain power output profile, and

in response to the electric machine operating to propel the vehicle over the predetermined route while the engine is shutdown and an upcoming increase in the powertrain power output profile to a value that is less than the threshold, maintain operating the electric machine to propel the vehicle over the predetermined route with the engine being shutdown.

2. The vehicle of claim 1 further comprising a starter motor configured to turn a crankshaft of the engine to start the engine.

3. The vehicle of claim 2 , wherein the controller is further programmed to operate the starter motor to initiate the engine start at the predetermined time period before the upcoming increase in the powertrain power output profile to the value that is greater than the threshold.

4. The vehicle of claim 1 , wherein the controller is further programmed to increase a pressure on the disconnect clutch to initiate the engine start at the predetermined period of time before the upcoming increase in the powertrain power output profile to the value that is greater than the threshold.

5. A vehicle comprising:

a powertrain having an engine and an electric machine;

an engine disconnect clutch configured to connect and disconnect the engine to and from the powertrain, respectively; and

a controller programmed to,

generate powertrain power output values to propel the vehicle at specified locations along a predetermined route based on navigation data,

in response to the electric machine operating to propel the vehicle over the predetermined route while the engine is shutdown and an upcoming increase in the values that is greater than a threshold, initiate an engine start at a predetermined time period before the upcoming increase in the values, and

increase a pressure on the disconnect clutch to initiate the engine start at the predetermined period of time before the upcoming increase in the values that is greater than the threshold.

6. The vehicle of claim 5 , wherein the navigation data includes static data.

7. The vehicle of claim 6 , wherein the static data includes a road grade of the predetermined route.

8. The vehicle of claim 6 , wherein the static data includes a speed limit of the predetermined route.

9. The vehicle of claim 6 , wherein the static data includes a road curvature of the predetermined route.

10. The vehicle of claim 5 , wherein the navigation data includes dynamic data.

11. The vehicle of claim 10 , wherein the dynamic data includes traffic conditions of the predetermined route.

12. The vehicle of claim 11 , wherein traffic conditions of the predetermined route include a traffic density of the predetermine route.

13. The vehicle of claim 10 , wherein the dynamic data includes weather conditions of the predetermined route.

14. The vehicle of claim 5 further comprising a starter motor configured to turn a crankshaft of the engine to start the engine, and wherein the controller is further programmed to operate the starter motor to initiate the engine start at the predetermined time period before the upcoming increase in the values that is greater than the threshold.

15. A vehicle comprising:

an engine and an electric machine;

an engine disconnect clutch configured to connect and disconnect the engine to and from a power path to a drive wheel, respectively; and

a controller programed to,

generate a power output profile required to propel the vehicle over a predetermined route based on navigation data,

in response to the electric machine operating to propel the vehicle over the predetermined route while the engine is shutdown and an upcoming increase in the power output profile to a value that is greater than a threshold, initiate an engine start at a predetermined time period before the upcoming increase in the power output profile,

in response to the electric machine operating to propel the vehicle over the predetermined route while the engine is shutdown and an upcoming increase in the power output profile to a value that is less than the threshold, maintain operating the electric machine to propel the vehicle over the predetermined route with the engine being shutdown, and

increase a pressure on the disconnect clutch to initiate the engine start at the predetermined period of time before the upcoming increase in the power output profile to the value that is greater than the threshold.

16. The vehicle of claim 15 , wherein the navigation data includes a road grade of the predetermined route, a speed limit of the predetermined route, a road curvature of the predetermined route, and a traffic density of the predetermine route.

17. The vehicle of claim 15 further comprising a starter motor configured to start the engine, and wherein the controller is further programmed to operate the starter motor to initiate the engine start at the predetermined time period before the upcoming increase in the power output profile to the value that is greater than the threshold.