A hybrid vehicle includes an internal combustion engine, an electrical storage device, an electric motor, an exhaust emission control device, and a controller. The internal combustion engine includes a variable valve actuating device. The variable valve actuating device is configured to change an operation characteristic (IN1a, IN2a, IN3a) of an intake valve. The electrical storage device is configured to store electric power. The electric power is generated by using the internal combustion engine. The electric motor is configured to generate a driving force of the hybrid vehicle by using the electric power stored in the electrical storage device. The exhaust emission control device is configured to purify exhaust gas from the internal combustion engine with the use of a catalyst. The controller is configured to execute catalyst warm-up control. The catalyst warm-up control is control for warming up the catalyst of the exhaust emission control device. The catalyst warm-up control includes first control (FIRST WARM-UP CONTROL) and second control (SECOND WARM-UP CONTROL). The first control is control for operating the internal combustion engine at a first operating point (P1). The second control is control for, after the first control is executed, operating the internal combustion engine at a second operating (P2) point irrespective of a driving force that is required to propel the hybrid vehicle. An output of the internal combustion engine at the second operating point (P2) is larger than an output of the internal combustion engine at the first operating

A compression ignition engine, commercial vehicle comprising such an engine, and a method for improving starting behaviour of such an engine. The engine is operable in a normal mode or a cold start mode. In the normal mode, a fuel injection system is controlled to inject a main fuel injection in a single pulse. In the cold start mode, the main fuel injection is split into a first split main and a second split main. The fuel injection system is controlled to inject the first and second split main in two distinct pulses, wherein the first split main is injected at a delayed timing for initiating a diffusion combustion phase in the pressurized combustion chamber, and wherein the second split main is injected during the diffusion combustion phase into the already combusting air-fuel mix.

A method of operating a vehicle including an engine includes suspending operation of the engine during operation of the vehicle including stopping fueling of the engine. The method includes accelerating the engine to a high-speed starting speed with fueling of the engine stopped and a cylinder decompression mechanism activated, the high-speed starting speed being greater than an idle speed of the engine. The method includes resuming operation of the engine including deactivating the cylinder decompression mechanism at the high-speed starting speed and thereafter restarting fueling of the engine.

An apparatus for adjusting power and noise characteristics of an internal combustion engine comprises a wall configured to define an engine cylinder that includes a bore and a compression relief passage. A compression relief valve is configured to selectively adjust fluid flow capacity of the compression relief passage. A manifold is configured to be in fluid communication with the exhaust passage and includes an exhaust bypass valve to permit exhaust to at least partially bypass a noise suppressor. Operational characteristics of the engine can be adjusted along a range that extends from a first set of operational characteristics present when both the compression relief valve and the exhaust bypass valve are in a fully open position to a second set of operational characteristics present when both the compression relief valve and the exhaust bypass valve are in a fully closed position.

A vehicle includes an engine, an exhaust flow passage, an air-fuel ratio sensor, and a control apparatus. The exhaust flow passage is configured to communicate with the engine. The air-fuel ratio sensor is provided in the exhaust flow passage. The control apparatus includes one or more processors, and one or more memories coupled to the one or more processors. The one or more processors are configured to: cause backflow of gas inside the exhaust flow passage while the vehicle is stopped; and diagnose a state of adhesion of oil inside the exhaust flow passage, based on a result of detection performed by the air-fuel ratio sensor in causing the backflow of the gas inside the exhaust flow passage.

A vehicle includes an engine, an exhaust flow passage, an air-fuel ratio sensor, and a control apparatus. The exhaust flow passage is configured to communicate with the engine. The air-fuel ratio sensor is provided in the exhaust flow passage. The control apparatus includes one or more processors, and one or more memories coupled to the one or more processors. The one or more processors are configured to: cause backflow of gas inside the exhaust flow passage while the vehicle is stopped; and diagnose a state of adhesion of oil inside the exhaust flow passage, based on a result of detection performed by the air-fuel ratio sensor in causing the backflow of the gas inside the exhaust flow passage.