Vehicle travel controller
A running control device of a vehicle executes a normal running mode with an engine coupled to drive wheels, a first inertia running mode with the engine stopped during running and an engine brake force reduced as compared to the normal running mode, and a second inertia running mode with the engine rotating during running and the engine brake force reduced as compared to the normal running mode. A determining portion determines a necessity of a brake negative pressure during the first or second inertia running mode. The necessity of the brake negative pressure is a condition for returning from the first inertia running mode and the second inertia running mode to the normal running mode. An upper limit value of the necessity of the brake negative pressure for returning from the first inertia running mode is smaller than that for returning from the second inertia running mode.
1. A running control device of a vehicle including an engine and a brake booster amplifying a brake force by using a brake negative pressure generated by rotation of the engine, the running control device of a vehicle executing a normal running mode with the engine coupled to drive wheels, a first inertia running mode with the engine stopped during running and an engine brake force reduced as compared to the normal running mode, and a second inertia running mode with the engine kept rotating during running and the engine brake force reduced as compared to the normal running mode, the running control device of a vehicle comprising a determining portion configured to determine a necessity of the brake negative pressure during the first or second inertia running mode, the necessity of the brake negative pressure being included as at least one of conditions for returning from the first inertia running mode and the second inertia running mode to the normal running mode,
the running control device of a vehicle having an upper limit value of the necessity of the brake negative pressure for returning from the first inertia running mode set smaller than an upper limit value of the necessity of the brake negative pressure for returning from the second inertia running mode, wherein
the necessity of the brake negative pressure is a magnitude of a negative pressure required for satisfying an amplification effect of the brake booster at the time of a predetermined brake operation.
2. The inning control device of a vehicle of claim 1 , wherein
the determining portion determines the necessity of the brake negative pressure such that
the necessity of the brake negative pressure is larger as a distance to a preceding vehicle is closer, such that
the necessity of the brake negative pressure is larger as a down-gradient is larger on a road surface where the vehicle is running, or such that
the necessity of the brake negative pressure is larger as a vehicle speed is larger when the vehicle is running.
3. The running control device of a vehicle of claim 1 , wherein
the first inertia running mode is a free-run inertia running mode that is an inertia running mode performed by disconnecting the engine and the drive wheels and stopping the engine during running, and wherein
the second inertia running mode is a neutral inertia running mode that is an inertia running mode performed by disconnecting the engine and the drive wheels and operating the engine in a self-sustaining manner during running.
4. The running control device of a vehicle of claim 1 , wherein
the first inertia running mode is a free-run inertia running mode that is an inertia running mode performed by disconnecting the engine and the drive wheels and stopping the engine during running, and wherein
the second inertia running mode is a cylinder resting inertia running mode performed by stopping a fuel supply to the engine with the engine coupled to the drive wheels and stopping operation of at least one of a piston and intake/exhaust valves in a part of multiple cylinders of the engine.