The Campro engine is the first automotive engine ever developed together with Lotus by the Malaysian carmaker, Proton. The name Campro is short for Cam Profile. This engine powers the Proton Gen-2, the Proton Satria Neo, the Proton Waja Campro, the Proton Persona as well as Proton's future models. The Campro engine is aimed to show Proton's ability to make their own engines that produce good power output and meet newer emission standards.
All Campro engines incorporate with drive-by-wire technology (specifically electronic throttle control) for better response,[1] eliminating the need for friction-generating mechanical linkages and cables. There have been some issues with cracking oil pumps but apparently Proton have introduced a new part recently to solve this problem. A recall has not been announced.
The Campro CPS engine uses a variable valve lift system (Cam Profile Switching system) and a variable length intake manifold (VIM; not to be confused with the stand-alone IAFM used in the 2008 Proton Saga) to boost maximum power and improve the CPS engine's torque curve over the standard DOHC Campro engine.
The engine's Variable-length Intake Manifold (VIM) switches between a long intake manifold at low engine speeds and a short intake manifold at higher engine speeds. Proton is using a longer intake manifold to achieve slower air flow; as they found this promotes better mixing with fuel. The short intake manifold allows more air in faster. This is beneficial at high RPMs[2].
The Cam Profile Switching (CPS) system uses a trilobite camshaft to switch between two different cam profiles. One cam profile provides low valve lift, while the other cam profile has a high valve lift. The low valve lift cam profile is used at low to mid engine speeds to maintain idling quality and reduce emissions, while the high lift cam profile is used when the engine is spinning at mid to high engine speeds improve peak horsepower and torque[2]. Unlike the other similar variable valve timing systems such as the Honda VTEC, the Toyota VVT-i and the Mitsubishi MIVEC which use rocker arm locking pins to change the valve timing, the CPS system uses direct-acting tappets with locking pins to change the valve timing and lift profile.[3]
VIM switches from the long to short runner at 4,800 rpm, while the CPS system switches over at 3,800 rpm (4,400 rpm in the Proton Satria Neo CPS[4]). The result is 125 bhp (93 kW; 127 PS) at 6,500 rpm and 150 N·m (110 ft·lbf) of torque at 4,500 rpm compared to the non-CPS Campro’s 110 bhp (82 kW; 112 PS) at 6,000 rpm and 148 N·m (109 ft·lbf) of torque at 4,000 rpm[2]. Proton claims that there is better response and torque at low engine speeds of between 2000 - 2500 rpm.
The new CPS engine first made its debut in the facelifted Proton GEN2 launched in Thailand[5][6], and made its first Malaysian debut in the Proton Waja Campro 1.6 Premium (CPS)[2]. Besides the 1.6L version, the Campro CPS engine is also available in 1.8L version; however, the bigger 1.8L version has not yet debuted in any of Proton's car (as on 30 April 2008) but rather made its first debut in a Malaysian-made hovercraft.
